Citation
Chemical engineering education

Material Information

Title:
Chemical engineering education
Alternate Title:
CEE
Abbreviated Title:
Chem. eng. educ.
Creator:
American Society for Engineering Education -- Chemical Engineering Division
Publisher:
Chemical Engineering Division, American Society for Engineering Education
Publication Date:
Frequency:
Quarterly[1962-]
Annual[ FORMER 1960-1961]
quarterly
regular
Language:
English
Physical Description:
v. : ill. ; 22-28 cm.

Subjects

Subjects / Keywords:
Chemical engineering -- Study and teaching -- Periodicals ( lcsh )
Genre:
periodical ( marcgt )
serial ( sobekcm )

Notes

Citation/Reference:
Chemical abstracts
Additional Physical Form:
Also issued online.
Dates or Sequential Designation:
1960-June 1964 ; v. 1, no. 1 (Oct. 1965)-
Numbering Peculiarities:
Publication suspended briefly: issue designated v. 1, no. 4 (June 1966) published Nov. 1967.
General Note:
Title from cover.
General Note:
Place of publication varies: Rochester, N.Y., 1965-1967; Gainesville, Fla., 1968-

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
01151209 ( OCLC )
70013732 ( LCCN )
0009-2479 ( ISSN )
Classification:
TP165 .C18 ( lcc )
660/.2/071 ( ddc )

UFDC Membership

Aggregations:
Chemical Engineering Documents

Downloads

This item has the following downloads:


Full Text




chmica ee education










ACKNOWLEDGMENTS

INDUSTRIAL SPONSORS: T /llowins compu1e0 hase donated

fs a Me tw dap2Oal o CHEMICAL ENGINEERING EDUCATION da~i~w 1973:


C F BRAUN & CO


MONSANTO COMPANY


THE 3M COMPANY


DEPARTMENTAL SPONSORS: A /oawiuf 12.9 depateia kw

co &dewil ia Me Lapef o4 CHEMICAL ENGINEERING EDUCATION in 1973


University of Alabama
University of Akron
University of Alberta
Arizona State University
University of Arizona
University of Arkansas
Auburn University
Brigham Young University
University of British Columbia
Bucknell University
University of Calgary
University of California (Berkeley)
University of California, Davis
University of California (Santa Barbara)
California Institute of Technology
Case-Western Reserve University
City University of New York
Clarkson College of Technology
Clemson University
Cleveland State University
University of Colorado
Colorado School of Mines
Columbia University
University of Connecticut
Cooper Union
Cornell University
University of Delaware
University of Detroit
University of Denver
Drexel University
Ecole Polytech, Canada
University of Florida
Georgia Institute of Technology
University of Houston
Howard University
University of Idaho
University of Illinois (Urbana)
Illinois Institute of Technology
Iowa State University
University of Iowa
University of Kansas
Kansas State University
University of Kentucky


Lamar University
Laval University
Lehigh University
Loughborough University (England)
Louisiana Polytechnic Institute
Louisiana State University
University of Louisville
McGill University
McMaster University
McNeese State University
University of Maine
Manhattan College
University of Maryland
Massachusetts Institute of Technology
University of Massachusetts
University of Michigan
Michigan State University
University of Mississippi
University of Missouri, Columbia
University of Missouri, Rolla
Montana State University
University of Nebraska
Newark College of Engineering
New York University
University of New Mexico
University of New Brunswick
University of New Hampshire
University of New South Wales
New York University
North Carolina State University
University of North Dakota
Northwestern University
University of Notre Dame
Nova Scotia Technical College
Ohio University
Ohio State University
University of Oklahoma
Oklahoma State University
Oregon State University
University of Ottawa
University of Pennsylvania
Pennsylvania State University
University of Pittsburgh


Polytechnic Institute of Brooklyn
Princeton University
University of Puerto Rico
Purdue University
University of Quebec
Queen's University
Rensselaer Polytechnic Institute
University of Rhode Island
Rice University
Rutgers-The State University
University of Rochester
University of Southern California
South Dakota School of Mines
State University of N. Y. at Buffalo
Stevens Institute of Technology
Syracuse University
Technion, Israel
Tennessee Technological University
University of Tennessee
Texas A&I University
University of Texas at Austin
Texas A&M University
University of Toledo
Tri-State College
Tufts University
University of Tulsa
University of Utah
Vanderbilt University
Villanova University
University of Virginia
Virginia Polytechnic Institute
Wayne State University
Washington State University
Washington University
University of Washington
University of Waterloo
West Virginia University
University of Wisconsin
Worcester Polytechnic Institute
University of Wyoming
Yale University
Youngstown State University
University of Windsor


TO OUR READERS: If your department is not a contributor, please ask your
department chairman to write R. B. Bennett, Business Manager, CEE, Depart-
ment of Chemical Engineering, University of Florida, Gainesville, Fla. 32601.
Bulk subscription rates at $4/yr each with a $25.00 minimum for six or
fewer subscriptions. Individual subscriptions are available to ASEE-CED and
AIChE members at $6 yr.









EDITORIAL AND BUSINESS ADDRESS
Department of Chemical Engineering
University of Florida
Gainesville, Florida 32601
US ISSN 0009-2479

Editor: Ray Fahien
Associate Editor: Mack Tyner
Business Manager: R. B. Bennett
(904) 392-0861
(904) 392-0881
Publications Board and Regional
Advertising Representatives:
SOUTH: Charles Littlejohn
Chairman of Publications Board
Clemson University
Homer F. Johnson
University of Tennessee
Vincent W. Uhl
University of Virginia
CENTRAL: Leslie E. Lahti
University of Toledo
Camden A. Coberly
University of Wisconsin
WEST: William H. Corcoran
California Institute of Technology
George F. Meenaghan
Texas Tech University
SOUTHWEST: J. R. Crump
University of Houston
James R. Couper
University of Arkansas
EAST :G. Michael Howard
University of Connecticut
Leon Lapidus
Princeton University
Thomas W. Weber
State University of New York
NORTH: J. J. Martin
University of Michigan
Julius L. Jackson
Wayne State University
Edward B. Stuart
University of Pittsburgh
NORTHWEST: R. W. Moulton
University of Washington
Charles E. Wicks
Oregon State University
PUBLISHERS REPRESENTATIVE
D. R. Coughanowr
Drexel University
UNIVERSITY REPRESENTATIVE
Stuart W. Churchill
University of Pennsylvania
LIBRARY REPRESENTATIVES
UNIVERSITIES: John E. Myers
University of California


SUMMER 1973


Chemical Engineering Education
VOLUME 7, NUMBER 3 SUMMER 1973

Departments
106 The Educator
Professor C. J. Pings
112 Departments of Chemical Engineering
SUNY at Buffalo, J. G. Vermeychuk
and J. A. Bergantz
117 The Classroom
Introduction to ChE Analysis, T.W.F.
Russell and M. M. Denn
142 International Chemical Engineering
A New Traditional Unit Operations
Laboratory Course, Aage
Fredenslund
110 Book Reviews

Special Aai'tawto 9d^dae
122 The Undergraduate ChE Laboratory,
H. S. Fogler, A. T. Perna, and F. H.
Shair
126 Bernoulli's Equation with Friction,
Noel de Nevers
129 The ChE Design Laboratory,
Harry Silla
132 Flow Modeling and Parameter Estima-
tion Using Radiotracers,
R. W. Rousseau, R. P. Gardner, and
R. M. Felder
136 A Computerized Undergraduate Process
Dynamics and Control Laboratory,
R. A. Schmitz
144 An Evolutionary Experiment,
A. Meisen
146 A Forced Convection Demonstration
Using Solid CO, Sublimation,
D. A. Mellichamp and 0. C. Sandall
148 An Integrated Reactor Engineering Lab-
oratory,
R. D. Williams

CHEMICAL ENGINEERING EDUCATION is published quarterly by the Chemical
Engineering Division, American Society for Engineering Education. The publication
is edited at the Chemical Engineering Department, University of Florida. Second-class
postage is paid at Gainesville, Florida, and at DeLeon Springs, Florida. Correspondence
regarding editorial matter, circulation and changes of address should be addressed
to the Editor at Gainesville, Florida 32601. Advertising rates and information are
available from the advertising representatives. Plates and other advertising material
may be sent directly to the printer: E. 0. Painter Printing Co., P. 0. Box 877,
DeLeon Springs, Florida 32028. Subscription rate U.S., Canada, and Mexico is $10 per
year, $6 per year mailed to members of AIChE and of the ChE Division of ASEE,
and $4 per year to ChE faculty in bulk mailing. Write for prices on individual
back copies. Copyright @ 1973. Chemical Engineering Division of American Society
for Engineering Education, Ray Fahien, Editor. The statements and opinions
expressed in this periodical are those of the writers and not necessarily those of the
ChE Division of the ASEE which body assumes no responsibility for them. Defective
copies replaced if notified within 120 days.
The International Organization for Standarization has assigned the code US ISSN
0009-2479 for the identification of this periodical.
105









F educator


ALIAS NEAL PINGS*







JACQUELYN HERSHEY
California Institute of Technology
Pasadena, CA 91109

Once upon a time a university professor
could, with a clear conscience, hew to his schol-
astic specialty and let administrative chips fall
where they might. But at Caltech those days are
long gone. In fact, it's a rare scholar who doesn't
have an administrative assignment outside his
classroom and lab. But "rare" is hardly adequate
to describe a man who takes on three or four.
Take C. J. Pings, professor of chemical en-
gineering and chemical physics, who is also execu-
tive officer for chemical engineering, vice provost,
and dean of graduate studies. Membership in a
clutch of committees and professional societies,
co-editorship of the journal Physics and Chemis-
try of Liquids, and editorship of a new journal
Chemical Engineering Communications round
out his multifaceted and admirable career.
Admirable, that is, except for his troubles
with the FBI. This blot on the escutcheon of
someone who has risen to such heights at his
alma mater-and become a highly respected
scientist elsewhere as well-dates back to 1951
when Neal was a senior at Caltech. Though he
had acquired the name "Cornelius" at birth in
1929 (via his father, his great-grandfather, and
his mother's sister Cornelia), he had adopted
"Neal" for all practical purposes. But the solemn-
ity of a possible job with the Atomic Energy
Commission after graduation led him to inscribe
"Cornelius" on his application. The AEC sent a
standard request for a recommendation to chem-

*Based on an article in Engineering and Science magazine,
October 1972. Published by The California Institute of
Technology.


istry professor Ernest Swift. His crisp reply that
he had never heard of any Cornelius Pings
brought a swarm of FBI agents buzzing around
Neal's hapless head.
"Living under an alias was over," says Neal.
"Before applying for any more jobs, I knew I
had to make the switch from Neal to Cornelius. I
started by going to the Registrar's office to get
my name changed on my transcript-and that's
when I found out my troubles had just begun.
There was no way, I was told, to make the change.
I produced my birth certificate; the Registrar's
staff was not impressed. I admitted that I had
lied about my name when I entered Caltech; they
suggested I get a court order for them to make
the alteration. I think we finally compromised by
putting Cornelius in parentheses on the records."
Cornelius John Pings is a native of Conrad,
Montana, a small rural community on the east
side of the Rockies. His family lived in Montana
because his grandfather had left the family home
in Wisconsin to take out a homestead in the West.
(A generation earlier his great-grandfather had
immigrated to the United States from Germany,
about the same time that his mother's ancestors
arrived from Ireland.) Neal's father struggled
through the Depression years as an electrician
with the Rural Electrification program, and
finally in 1942 went looking for his greener pas-
tures in California.
Those early years of economic insecurity gave
Pings some sturdy opinions about what an educa-
tion is for. The quest for knowledge excited him,
but a strong motivation for getting a college de-
gree was its promise of economic benefits.
Neal entered Caltech planning to become a
nuclear physicist-an ambition that lasted just
one term. But chemistry immediately filled the


CHEMICAL ENGINEERING EDUCATION














Neal had
a headon
verbal collision
with the
dietitian.


-3>


void-perhaps, he suggests, partly because of the
quality of instruction he received. Linus Pauling
and Norman Davidson taught him freshman
chemistry, and Ernest Swift was his instructor
in sophomore year. ("Anyone who survived that
course will testify to its intellectual thorough-
ness.") Howard Lucas, professor or organic
chemistry, taught him most of what he knows
about laboratory techniques.
With visions of going to work eventually for
a chemical or petroleum company, Neal took his
BS in applied chemistry-having financed four
years of college with a combination of scholar-
ships, summer jobs, and student loans. And with
the hope that this eventual job would be one of
substantial technical responsibility in industry,
he persisted through a PhD program in chemical
engineering. It was with some surprise, then,
that in 1955 he found himself turning down some
attractive job offers in industry to go with his
fellow alumnus Dave Mason, then on the staff at
JPL, to set up a new CHE department at Stan-
ford. "I decided to try academic life for one
year," he says, "and I've been at it ever since. So
much for my industrial aspirations. But I often
tell students about myself when they ask me for
career advice. My experience is that flexibility is
an asset."
Neal will testify that a little flexibility can
take a man a long way-to northern Greenland,
for instance. Thanks to his reading a notice
posted on a campus bulletin board, that's where
he spent the summers of 1955, '56, and '57. Grad-
uate student Mark Meier, now a noted authority
on glaciers, was organizing a geology field trip
and recruiting a staff.


"There's a component of engineer in me but I
wanted to go into the hard science aspects of
the liquid state ... Now, the problems are
far from solved, but I think we've made
some progress."

Right then, Neal liked what that job offered-
summer work, distance from Pasadena, outdoor
life, and moderately good pay. It also made good
use of his research background (heat transfer
3-CHEM ENG-10 cent on 12-20 11957 Bill
and thermodynamics), and he is still proud of
three professional papers resulting from the ex-
perience. ("And my children are still young
enough to be impressed when I point to Green-
land on the globe and say, "I was there.' ")
After four years at Stanford, Neal came back
to Caltech in 1959 as associate professor and as
resident associate for Fleming House. Two prob-
lems cropped up soon after he arrived. The first
was overcoming his student-bred reticence at
calling senior faculty members by their first
names. Will Lacey, now professor emeritus, cured
that difficulty with a few well-chosen words.
"You've graduated from calling me Doctor," he
said. "My name is Will!"







He and .
Marjorie
were married
in 1960 ....

i. __-6

r n-



The other problem was that hardy perennial
-complaints about student-house food. As resi-
dent associate, Neal had a headon verbal collision
about it with the dietitian and manager of the
student houses. Marjorie Cheney. His recollec-
tion of the effectiveness of his battle in behalf
of an improved cuisine is hazy.( Marjorie says:
"At first I thought that he would be easier to
cope with than the undergraduates, but .!")
One result was an "honest-to-God campus ro-
mance." He and Marjorie were married in 1960.


SUMMER 1973








Neal made a decision in his first year at Stan-
ford about the general area of research he wanted
to pursue-to understand liquids at the molecular
level. He was struck by the fact that a fairly
sizable body of knowledge existed about gases and
solids, but comparatively little about liquids.
"There's a component of engineer in me," he
says, "but I wanted to go into the hard science
aspects of the liquid state. My experiments have
been designed to lead ultimately to better theory,
which may then be applied to practical problems.
Now, 16 years after I started, the problems are
far from solved, but I think we've made some
progress."
Neal and his research group are currently in-
terested in mixtures. Understanding mixtures by
the brute force of numbers of experiments is
hopeless; there are too many possibilities. The
aim is to develop some rules for utilizing what
is known about simple substances to say how they
will behave when they are combined.
Essentially, the research is divided into three
sub-groups, each involving use of a different
technique and the simplest available systems
(monatomic rare gases such as argon and kryp-
ton, which are liquid at the temperatures and
pressures used in the experiments).
The technique Neal started working with,
which is still the backbone of his research, is that
of X-ray diffraction. Using it, his students are
able to measure the structure of fluids-the aver-
age number of neighboring atoms and their dis-
tance apart.
The second technique is a study of the refrac-
tive index of fluids, chiefly between liquid and gas.
The refractive index is a measurement of how
much a beam of light is bent as it stabs through a
liquid. The amount of bending is indicative of the
electrical environment of local areas of the liquid
and also gives some idea of its density.
The third technique is to use lasers for light-
scattering to study the motion of the molecules in
fluids. This is fairly new, and with it Neal says,
"We can make some very exciting measurements
and get some wholly new information. And we
don't yet have any idea of its full potential."
While the orientation of Neal's research
group is basically experimental, he makes sure
that they keep in touch with theoreticians. "We
try to find experiments to challenge or confirm
the theories we hear about," Neal says. "Then,
from our data, we are able to suggest new
approaches to the theoreticians, and we listen


W '4 Admirable,
except for
his troubles
with the FBI ...






when they suggest what we should be doing in
the laboratory."
Of course, Neal doesn't listen to just the local
theoreticians. He is a regular participant to scien-
tific meetings, including the Gordon conferences.
The Gordon Research Conference on the Physics
and Chemistry of Liquids meets biennially, and
Neal has attended the last seven of them. (He
was chairman of the one in 1969). Attendance is
limited to 120 researchers, carefully chosen for
a good mix between already established and
younger scientists. "Those conferences are a
beautiful experience," Neal says. "For one whole
week you're with your colleagues-theoreticians
and experimentalists-in continuing conversa-
tion. And we correspond over the intervening
months too-asking questions, checking results,
making suggestions. I grumble a lot about meet-
ings, but not about these."
Bringing ability and good nature to his meet-
ings, Neal makes both friends and progress in the
process. Some of his success must surely stem
from his genuine commitment to Caltech and to
higher education. "I want to do what I can to help
both of them thrive, to adapt to changing times,
and to stay ahead of their problems," he says.
Neal has taken some razzing about the num-
ber of jobs and titles he carries, but he doesn't
feel that his case is noteworthy. "A lot of people
around here are carrying administrative tasks
and practicing the trade simultaneously," he says,
"and it's not all that hard. The bureaucracy is
minimal, which makes it possible to get hold of
people and talk things out. Of course, you have to
make choices. I regret losing some of the rapport
I used to have with undergraduates. I missed
teaching last year, so I'm glad to be back at it
now-giving the thermodynamics course.
I suppose there's some ham in me, but to stand


CHEMICAL ENGINEERING EDUCATION









up in front of a class and feel you're conveying
knowledge and maybe affecting attitudes can be
very satisfying. But I won't go into class half
prepared."
Juggling the requirements of his various
posts and his available time also keeps Neal from
getting into the lab to make his own measure-
ments. But he meets with his research group
(smaller in these days of funding difficulties than
it used to be) as often as he can, and he makes
himself available for conferences on individual
problems. The formalities of setting up such
meetings are a little more complex than they once
were, but he feels responsible for keeping track
of what's going on and trying to be helpful.
William Corcoran, professor of chemical engi-
neering and vice president for Institute relations,
who has known him since 1952, puts the matter
succinctly: "Nobody ever gets short changed by
Neal."
The list of Neal's contributions over the years
on many Caltech administrative and faculty com-
mittees is a long one, and his chairmanship of the
Ad Hoc Committee on the Aims and Goals of the
Institute (1969-1970) epitomizes that kind and
degree of service. Rodman Paul, Harkness Pro-
fessor of History, who has known Neal since he
taught him history as an undergraduate, was
also a member of that committee. He recalls that
through all the long months of its deliberations
Neal "displayed tremendous fairness, calmness,
and breadth of understanding. He is a good scien-
tist who deals with human beings in human ways.
When Harold Brown was chosen as president of
the Institute, it was clear that somehow he would
have to be thoroughly briefed. It was Neal more
than anyone else who pointed out that the report
of the Aims and Goals Committee would be ex-
actly what was needed to do the job. So, we
shoved it through with a speed that didn't seem
possible, and gave it to the president. I think
it was the most thorough analysis and appraisal
of Caltech that has ever been made."
Neal says, "Working on that committee con-
vinced me-and others-that an institution like
this doesn't run itself. We're fortunate here that
the faculty is involved in decision making. It was
clear at the time the committee was appointed
that we were heading into a period when we were
going to be subject to severe constraints, that we
were going to have to live by our wits. There
were going to be choices and decisions, and if the
faculty wanted to get in on those, it was going to


Neal's administrative
posts include executive
officer, vice provost,
and dean of graduate
studies.





have to make its views known and some of its
members available for administrative positions.
It's probably not a coincidence that 60 percent of
the committee's members have ended up in ad-
ministration."
Neal's own administrative posts include being
executive officer for chemical engineering, vice
provost, and dean of graduate studies. One reason
he continues as executive officer is that the chemi-
cal engineering faculty is, on the whole, very
young and involved in starting their own research.
"It doesn't make sense to dilute their time with
administration at this point," says Neal. "We're
really victims of our own strategy, because we
have deliberately been recruiting young men-
but it will pay off in the long run."
Most of the day-to-day operations of the grad-
uate office-admission and support of students,
management of the office, direct contact with the
various option representatives, and participation
in national and regional groups concerned with
graduate education-have been turned over to
Associate Dean Stirling Huntley, with Neal being
involved in policy making, budgeting, and work-
ing with the Graduate Studies Committee.
As vice provost, he has specific responsibility
for all new and renewal appointments on the re-
search ladder, for the faculty portion of the Insti-
tute's Affirmative Action Program, for the library
and the Industrial Relations Center, and for in-
terdisciplinary programs. Basically, however, he
sees his task to be relieving the load carried by
Provost Robert Christy. Somewhat ruefully he
points out: "We have to handle questions that
once didn't even arise: How do you try to do as
much, and maybe more, research on less money?
How do you keep a young faculty when you can't
afford to appoint new people?
"There are lots of kinds of jobs around here,
and I like to sample them," says Neal. "I enjoy


SUMMER 1973









feeling useful; I like to free time for others to do
what they want to do. And there's enough of the
competitor in me that I don't mind working at
being successful. Each of my jobs calls on differ-
ent talents, responses, parts of temperament, and
combinations of whatever abilities I have. And
each makes vulnerable different kinds of short-
comings. Research demands analytical thought
processes plus whatever creativity I have, and
that rather severely exposes the limits of my in-
tellect. Supervision of personnel and administra-
tion in general require exercising judgment on
problems dominated by values and the ramifica-
tions of human personality. I often find myself
failing in these situations-either because I try
to find an exact answer to a diffuse problem or, at
the other extreme, I compromise in making a
difficult decision because I give in to a desire to
be liberal or compassionate."
Administrative work is harder than either
teaching or research as far as Neal is concerned
-a fact which, he thinks, may reflect his lack
of training in its techniques. The problem boils
down to persuading other people to do things for
him, and he attacks it by assuming that the people
he deals with are reasonable individuals.
Like many another Caltech professor, Neal
often takes a loaded briefcase home. Even when
he leaves his work at the office, he finds it hard
to take a real break from his duties unless his
family can lure him out of town-preferably to
the mountains or the beach. He feels that he is
overdue for a leave of absence for about six
months at another university. Such breaks in
routine lend perspective. But he expects the ex-
perience will just confirm his conviction that Cal-
tech really is an outstanding place.
He has been investing in that conviction for
a long time. As an undergraduate Neal Pings was
a member of the Beavers, the Board of Control,
the Interhouse Committee, Throop Club, and-
with real devotion-the varsity football team. All
this adds up to top-notch credentials for his elec-
tion to the board of directors of the Alumni Asso-
ciation. He took on this three-year job in 1970
not only because he was interested but because he
had a two-way feeling of responsibility. He be-
lieves the faculty hasn't made adequate use of the
talents of the alumni, and that the alumni could
do a lot more for Caltech. As a man with a foot
in each camp, he thinks he may be able to im-
prove communications between the two groups.


If Neal's services as vice chairman of Pasa-
dena's Community Redevelopment Agency seem
tangential to the academic circle in which he
usually operates, the appearance is only super-
ficial. He's not there as an official representative
of Caltech, but he points out: "I'm concerned
that 20 years from now Caltech will be located in
a city where it's still pleasant to live and to send
children to school. The decisions that are being
made right now will affect that. Faculty members
here have always been involved in national
affairs, but local involvement is just as important.
Caltech can't isolate itself from Pasadena, and
maybe I can be a bridge."
Not even the FBI could find anything wrong
with that.


IM book reviews

Introduction to Chemical Engineering Analysis,
T. W. F. Russell and M. M. Denn, 502 pp., John
Wiley and Sons, Inc., New York, 1972

Do not be misled by the title of the book: this
is not just another textbook for an introductory
stoichiometry course. The fundamental approach
is that of an integrated view of the entire typical
chemical engineering curriculum. The authors
have decided that it is time to use something
other than furnaces and sulfuric acid plants to
form the background for such an introductory
course. Their choice is the fluid-filled vessel, in
many of its ramifications. Real chemistry is used
throughout.
Those familiar with the structure of the chem-
ical engineering curriculum will find that there
are several mini-texts included here. Kinetics,
design, extraction, reactors, energy balances, pro-
cess dynamics, and mixing are all present. The
introduction does a good job of intriguing the
student, and the second and third chapters form
a reasonable introduction to modeling principles.
There is also a chapter on data analysis in the
midst of other topics.
The first law of thermo-energy balances is
covered well. There are accompanying mini-texts
on convective heat transfer, non-isothermal re-
actors, and gas behavior.
Perhaps of more interest to the potential
user is what is not in this book. There is no sepa-
rate treatment of material balance principles.
(Continued on p. 128)


CHEMICAL ENGINEERING EDUCATION







Over half the towns in the United States

are forced to dump their wastewater in our rivers.

The reason is sad.


Money. Literally over half our towns
haven't got enough money to build com-
plete wastewater treatment plants.
And many towns that have complete
plants aren't cleaning the water thoroughly
because the towns have outgrown the
plants. And they can't afford to expand.
So, because of money, towns are forced
into polluting our streams and rivers.
Union Carbide has discovered a new
wastewater system that costs less. Ifs called
the Unox System. Ifs the first substantial
change in wastewater treatment in thirty
years.
Instead of the conventional aeration sys-
tem that cleans water by mixing it with the
air, Unox forces pure oxygen into a series
of closed treatment tanks. This forced oxy-
gen technique cleans wastewater in less


time, less space and reduces the total cost
up to forty percent.
It means a town can boost its wastewater
system by simply adapting the Unox Sys-
tem to the existing system. And towns with
limited means can now afford a complete
system.
A number of cities andindustries through-
out the country have already chosen the
Unox System. And more installations are
being planned.
We've discovered a cheaper way to treat
wastewater because our streams and rivers
can't afford to wait.


BSl
=RB I D


THE DISCOVERY COMPANY
270 Park Ave.. NewYork. N.Y. 10017


For additional information on our activities, write to Union Carbide Corporation, Department of University Relations, 270 Park Avenue, New York, New York 10017. An equal opportunity employer.




























SUNY AT BUFFALO

J. GREGORY VERMEYCHUK and
JOSEPH A. BERGANTZ

In a brief existence spanning but a dozen
years, the Department of Chemical Engineering
at the State University of New York at Buffalo,
which began with a faculty of three and a hand-
ful of students, has rapidly developed into a full-
scale operation with thirteen faculty members
and a sizeable graduate program. Buffalo's ChE
department is the only such department in the
State University of New York. The SUNY system
comprises four major graduate centers, many
four-year Colleges, a multitude of two-year insti-
tutions, and a number of special purpose installa-
tions. The entire system serves approximately
115,000 students, while the graduate center at
Buffalo, including its noted medical school, has
an enrollment of 22,000, distributed among two
major campuses and a collection of other sites
throughout the city and its environs.
On a 1000 acre site to the North of the city,
construction proceeds apace on a totally new, $650
million campus. This, and a number of other fac-
tors, suggest a period of continued growth for
our department.
The Department of Chemical Engineering is
one of six engineering departments in the Faculty
of Engineering and Applied Sciences. FEAS and
six other Faculties constitute the University Cen-
ter at Buffalo. Due to the nature of this form of
organization, students and faculty can work
within the atmosphere of a small engineering


school, yet have the tremendous diversity and
varied human and material resources of a major
university within easy reach.

THE STAFF AND ITS ACTIVITIES
It is a truism that the quality of an academic
department may be gauged by the qualifications
of each faculty member. The staff of our depart-
ment incorporates expertise in all the classical
areas of ChE, and in a number of specialized
areas related to ChE, such as process metallurgy,
environmental and biomedical engineering, and
modern control theory. The faculty maintains an
extensive and productive program of research,
as indicated by approximately 50 journal articles
published during the 1971-72 academic year.
Several books and edited conference proceedings
by faculty have also appeared during the past two
years.
Since our departmental faculty is drawn from
a range of educational backgrounds (three of our
number received the Ph.D. degree in physical
chemistry), joint research projects crossing de-
partmental bounds are inevitable. Many of our
research publications result from collaboration
with cell biologists, mechanical engineers, physi-
cians, geologists and chemists.
In addition to the usual man-to-man research
collaboration, the structure of the University
allows the development of more formal means of
interdisciplinary academic activity. A Center for
Process Metallurgy was formed in 1969 to per-
form research on problems related to the steel
and other metallurgical industries. Two of the
three professors involved in the center, including
the director, are members of the Department of


CHEMICAL ENGINEERING EDUCATION









In ... but a dozen years, the Department which began with a faculty of three has developed
into a full-sized operation with 13 faculty members and a sizeable graduate program.


Chemical Engineering. This Center, in addition
to funding provided by industrial firms, has re-
ceived a grant from the NSF/RANN program for
the investigation of the applications of optimiza-
tion to the steel industry.
Three chemical engineers are members of the
Center for Theoretical Biology, which carries on
investigations in many diverse areas germane to
the biological sciences, and which publishes the
Journal of Theoretical Biology. Two other mem-
bers of our faculty have provided papers pub-
lished in this journal.
Another member of our department founded
and has served as Master of the Rachel Carson
College, an established undergraduate center for
the study of modern technology and its impact on
the environment.
For the area of undergraduate and graduate
teaching, our department is comparably active.
Innovation in teaching has been an important
theme. Two noteworthy new courses appearing in
the present academic year are a lower division
offering in Introduction to Chemical Engineering,
providing a modern approach, and a graduate
course in the Applications of Immobilized
Enzymes.
ChE faculty members also serve as instruct-
ors in FEAS-wide sophomore level courses in
thermodynamics and materials science. These
two courses provide the basic introduction to
these topics for all engineering students within
the University.
The matter of undergraduate advisement
ranks high in importance. Advisement seminars
are presented to all engineering freshmen, and
an extensive advisement brochure assists our
undergraduates in tailoring their individual pro-
grams to specific needs.
Perhaps the best way to provide an in-depth
look at our department is to consider each mem-
ber of our faculty on an individual basis.

JOE BERGANTZ is the man responsible for the crea-
tion of the department and served as our first chairman.
In this position, Joe hired most of the present faculty.
Additionally, he has served as Acting Provost of the
Faculty of Engineering and Applied Sciences. Joe's cur-
rent research interests lie in the investigation of gas-
solid reactions which can be used to purify manufac-
tured gaseous fuels (i.e., resulting from the gasification
of coal) without loss of thermal efficiency.


Joe
Bergantz:
the man
responsible
for creation
of the
department.









DON BRUTVAN, one of the original members of the
department, now holds but a one-eighth-time appoint-
ment, since his prime function lies in University Admin-
istration. Don is Associate Dean of the Division of Con-
tinuing Education which serves some 6500 students, in
both credit-carrying and credit-free programs.
HARRY CULLINAN, our present chairman, joined
the department in 1964. Harry is continuing his experi-
mental program for the determination of selected liquid-
phase diffusion coefficients. This program makes use of
a novel ultracentrifugal equilibrium sedimentation tech-
nique for the determination of the composition deriva-
tives of chemical potential for multicomponent liquid
mixtures. He is also conducting theoretical work to show
how the principles of non-equilibrium thermodynamics
apply to the solution of coupled transport phenomena.
During 1972-73, Harry has been on Sabbatical leave at
the University of Manchester Institute of Science and
Technology, Manchester, England.
PAUL EHRLICH, a physical chemist by training,
teaches both graduate and undergraduate courses in poly-
mer materials, polymerization, and thermodynamics. Paul
has completed experimental measurements and a theoreti-
cal analysis of the volumetric properties of ethane-n-hep-
tane mixtures in the supercritical region, including the vi-
cinity of the critical locus, and plans to extend his work to
other paraffin mixtures. Plans are also underway for new
studies of the observed divergence from classical predic-
tions of thermodynamic and transport properties of ma-
terials at the critical-locus. Paul also has completed an
ESR study of crystallizable, high-molecular weight
polythenylacetylene. This work promises to be of sig-
nificance in the design of improved polymeric semiconduc-
tors and photoconductors.


SUMMER 1973















Bill Gill,
Provost, also
supervises
two post-docs
and nine
graduate
students.







BILL GILL, who joined us in September, 1971, is
Provost of FEAS. The heavy administrative load has not
impeded his program in teaching and research, however,
Bill currently supervises a group of two post-does and
nine graduate students. With R. Sankarasubramanian,
he continues the development of a new solution technique
for convective diffusion problems by generalization of
their original approach to dispersion problems to include
interphase transport and chemical reaction. Bill and
M. Doshi are working on a countercurrent ion exchange
unit and have succeeded in markedly increasing the
efficiency of such units. This work has led to a simple
model which seems to explain the effects of bypassing
quite adequately. He is studying both theoretically and
experimentally the properties of tubular and hollow-fiber
reverse osmosis systems. Experimental work with L.
Derzansky has shown that natural convection in tubu-
lar R. O. systems has a significant bearing on perform-
ance. An analysis of hollow fiber systems has led to
an approach to optimal design which appears to hold
promise. In collaboration with GREG VERMEYCHUK a
study is underway on the oxygenation of liquids in open-
channel turbulent flow. Greg and Bill are preparing an
experimental study of the effectiveness of diffusion
boundary layer withdrawal in the improvement of per-
formance in R. O. systems. Alternating sections of selec-
tive and non selective membranes will be used.
Another physical-chemistry trained member of our
department is BOB GOOD. Bob has recently shown that
certain anomalies in the rate of penetration of a liquid
into a porous body such as a bed of powder, or a capillary,
can be explained with the aid of a generalization of the
Washburn equation for capillary flow. He has discovered
an anisotropic effect in the wetting of stretch-oriented
polymers, and a heat effect in the peeling of a pressure-
sensitive tape. He has developed a general theory of the
contact angles of liquids on solids and has very recently
published a theory that is an important advance in the
understanding of interfacial separation in adhering sys-
tems. He has shown that the adhesion of living cells to
each other in tissues is due to forces that physical
chemists and chemical engineers have been studying for
a number of years, with respect to the stability of emul-
sions and solid-in-liquid dispersions. This last develop-


ment has important consequences in embryology, and in
research on cancer. Bob is also a member of the Center
for Theoretical Biology.
JOHN HOWELL'S research is directed toward many
important problems in the environmental area. He is
currently performing theoretical and experimental in-
vestigations on the effects of wall growth of organisms
in biological reactors. Such effects have been shown to
be of great significance when scale-up of biological re-
actions is to be done. John is currently performing
studies on the use of certain types of biological reactors
for the production of single cell protein to be used as an
animal feed supplement, and for the treatment of indus-
trial wastes. John is offering a new graduate course in
immobilized enzyme technology, and, with the help of
Greg Vermeychuk, produced a totally new selection of
undergraduate advisement materials. John had served
as Master of the Rachel Carson College until recently,
when he left the post in order to devote full time to the
department.
KEN KISER'S research work shows a strong inter-
disciplinary orientation. He collaborates with members
of the Civil and Mechanical departments in the use of
their unique rotating models of Lakes Erie and Ontario
to characterize the spread of material and thermal pol-
lutants in these bodies of water. With members of
Mechanical Engineering and the medical School he seeks
to experimentally determine velocity profiles in the aortae
of living dogs. This work will provide information neces-
sary for the design of better artificial heart valves for
human patients. Ken is also conducting experimental
work on mixing in turbulent jets.
HARMON RAY'S interests in process modelling, optim-
ization and control have led him into many diverse fields.
He has developed rigorous quantitative descriptions for
a number of polymerization systems including copoly-
merization and heterogenous polymerization reactors.
Another major area of interest has been the modelling
and optimization of catalytic reactors experiencing cat-
alyst deactivation, and he has developed several efficient
optimization algorithms for treating these problems.
More recently, Harmon has collaborated with JULIAN
SZEKELY to apply modern optimization and control
techniques to the problems of the steel industry. In order
to acquaint the metals processing industry with these
ideas, Harmon and Julian have (for the past 3 years)
put on a 3-day intensive course entitled "Optimization in
Process Metallurgy" which has been well attended by
industrial people and professors alike. Harmon and
Julian's interest in Optimization, as applied to a number
of fields, have led to their recently published monograph
entitled "Process Optimization" (Wiley 1973). Harmon
has also been active in the field of process dynamics,
estimation and control and has contributed papers in a
number of areas. These include the control of systems
having time delays in the state, control, or measuring
device, as well as the dynamic behavior of chemical re-
actors. Harmon's research efforts in process control were
recognized in 1969 when he was presented the Donald
P. Eckman Award of the American Automatic Control
Council.


CHEMICAL ENGINEERING EDUCATION









JULIAN SZEKELY, Director of the Center for
Process Metallurgy is active both within the field of
Chemical Engineering and Process Metallurgy. He is
one of the pioneers of the application of chemical en-
gineering techniques to metals processing operations.
The co-author of two texts, Rate Phenomena in
Process Metallurgy (with N. Themelis) and Process Op-
timization with Harmon Ray, he has also edited two
volumes, Blast Furnace Technology and The Steel In-
dustry and the Environment.
Julian's research ranges from bubble dynamics, turbu-
lent flow in solidification to gas-solid and solid-solid re-
actions, and scrap-melting kinetics. Julian publishes ex-
tensively in both the chemical engineering and the
metallurgy literature and his work has been recognized
by the "Junior Moulton Medal" (British Institution of
Chemical Engineers, 1964), the D.Sc (Eng) degree (Uni-
versity of London, 1972), The extractive Metallurgy Di-
vision (A.I.M.E.) Science Award (1973) and the Mathew-
son Gold Medal (A.I.M.E.) also in 1973.


Laboratory
in the
center for
Process
Metallurgy.


S K


GREG VERMEYCHUK is extending his work on
suboptimal feedback control of systems described by
partial differential equations. He is developing new com-
putational algorithms and applying them to models of
tubular reactors with the goal of providing more effec-
tive and reliable software packages for direct digital
control installations. It is expected that this work will
extend the range of direct digital control to include more
complex systems of practical importance.
Since joining the department in September, 1971,
Greg has started to branch into other research areas.
He is collaborating with Bill Gill on a combined theoreti-
cal and experimental study of the use of specially de-
signed membranes to improve reverse osmosis systems
for desalination of water and other applications. Greg
will work with Bill in the study of mixing and dispersion
in open channel flows. This work will have great im-
portance in assessing the downstream effects of concen-
trated sources of pollution, such as industrial discharges.
Greg has also developed a new sophomore-level intro-
ductory course in chemical engineering.


TOM WEBER has developed a number of models to
describe the behavior of adsorption beds. For gas-solid
systems, one model accounts for the coupling of the heat
transfer and mass transfer effects. This model was suc-
cessfully tested using a gas mixture of ethane and helium
with activated carbon. More recently, he has turned his
attention to liquid-solid systems because of their potential
importance in waste water treatment. Both pore-and
solid-diffusion models are being explored, as well as the
possible effects of axial dispersion. Tom has collaborated
with Ken Kiser in a recent study of heat transfer in
pulsed laminar flow.
Tom is also interested in process dynamics and control.
He is carrying on some work on multivariable processes
with interactions. As an outgrowth of his teaching in-
terests in control, he has written an undergraduate text-
book, An Introduction to Process Dynamics and Control,
which will be published by Wiley-Interscience in June.
Tom also coordinates credit-free technical courses and
programs in the Division of Continuing Education.
Last, but by no means least, comes our present Acting
Chairman, SOL WELLER. Far from new to administra-
tive matters, Sol has served as Acting Chairman before,
as well as having held research management posts in
industry before joining the Buffalo faculty in 1965.
Sol's study of the supported metal and transition
metal oxide catalysts has shown that the special chemical
properties of surface ions can help to explain their
catalytic behavior and their tendency to sinter. He is
using alumina-deficient mordenite to develop a simple
picture for the catalytic action of zeolites. And he is
applying the Frank-Kamenetskii theory of ignition and
quenching at the surface of catalytic wires as a tool to
optimize activation techniques for metals. As chairman
of a U.N. committee, he is active in establishing inter-
national standard test methods for catalysts. Finally, as
a member of the Center for Theoretical Biology at
Buffalo, he is involved in planning Viking experiments
to search for the existence of life on Mars.

THE UNDERGRADUATE PROGRAM
The undergraduate program in chemical en-
gineering of Buffalo has many unusual features in
addition to the rather standard offerings which
typify such programs. Within a University-wide
framework of thirty-two courses of four credit-
hours each as a requirement for the Baccalaur-
eate degree, we have designed our program to
afford each student the maximum flexibility in
tailoring a program which suits his or her indi-
vidual needs. In addition to standard lower-divi-
sion requirements of mathematics, chemistry, and
physics, there are required faculty-wide courses
in the principal engineering sciences. The courses
in materials and engineering thermodynamics are
often taught by members of our department. The
courses in thermodynamics are worthy of note,
since the Department of Chemistry accepts these


SUMMER 1973







courses as sufficient preparation for the second
course of a two-course sequence in physical chem-
istry. The normal requirement of the first course
is waived for ChE students.
As soon as they are identified, departmental
majors are assigned faculty advisors who help
the student make the most out of his or her elec-
tive courses. Since ChE undergraduates often
enter graduate or professional programs in man-
agement, law, medicine, and other diverse fields,
the needs of different students vary widely.
Certain unique features of our undergraduate
program include the two-semester senior level
course sequence entitled Applied Chemical Engi-
neering, or simply, "ACE." In the ACE sequence,
students are exposed to detailed treatments of
ChE unit operations from a theoretical point of
view, coupled with a series of small design proj-
ects. With modifications, over the years, this
course has been quite successful, especially with
the more practically oriented students. Since the
course requires intensive preparation, it is usually
team-taught by two professors.
Undergraduates interested in environmental
problems have the opportunity to enroll in the
Rachel Carson College, a comprehensive living-
learning unit specializing in technological/en-
vironmental studies.
The students provide valuable feedback on
the degree of success of our teaching efforts in
evaluations conducted each semester by the Office
of the Provost. In such a climate, dedication to
teaching obviously flourishes.
We have had some success in encouraging
women to enter the profession. Of our 1973 senior
class of twenty there are three women.

THE GRADUATE PROGRAM
The department offers courses of study lead-
ing to both the M.S. and Ph.D. degrees in Chemi-
cal Engineering. Of the 50 students in residence
at this time, 20 are formally pursuing Ph.D. re-




f lWeller and
Howell at
informal
faculty
gathering.


Scanning Electron Microscope.
search. Up to June of 1972, 16 Ph.D. and 55 M.S.
degrees have been awarded. Of the Ph.D.'s, 6
have obtained university teaching positions, both
in the U.S. and abroad. The department expects
to award 17 M.S. and Ph.D. degrees in the 1972-
73 academic year.
Graduate research is very active, as detailed
in the section on the activities of the staff. To
speak in general terms, however, our graduate
program offers definite strengths in process
metallurgy, materials (notably polymers) and
environmental studies as well as the more com-
mon aspects of chemical engineering. These
strengths are expected to be developed further
when the department moves to the new North
Campus in 1976-77.
Graduate course offerings are many and
varied. Students are encouraged to take courses
outside the department in order to augment their
research interests and to broaden their back-
ground.
IN SUMMARY
From all that has been presented above, and
from observation of the day-to-day workings of
our faculty and students, one may characterize
the department at Buffalo as young, and prepar-
ing to enter a phase of growth.
The addition of Drs. Gill, Ray, and Vermey-
chuk, all in the past two and one-half years, has
increased the scope of departmental research.
For September 1973, Professor Eli Ruckenstein
will come to Buffalo as Faculty Professor of En-
gineering and Applied Sciences. Professor Ruck-
enstein is already interacting on research prob-
lems with three members of the department, and
will be offering courses within the department


CHEMICAL ENGINEERING EDUCATION










I classroom


INTRODUCTION TO CHE ANALYSIS


T. W. F. RUSSELL and M. M. DENN
University of Deleware
Newark, DE 19711

The transition of chemical engineering educa-
tion during the past two decades from an empiri-
cally based, design oriented curriculum to the so-
called "engineering science" approach has been
neither smooth nor totally successful. Today's
curricula have been justifiably criticized for fail-
ing to teach applications of principles, and the
new trend appears to be a "return to design." A
principle-based curriculum can be oriented to-
wards practical engineering application and pro-
vide the necessary blending of design and engi-
neering science. The resolution lies in imagina-
tive use of the introductory course in chemical
engineering, usually taught at the sophomore
level.
The sophomore course in Industrial Stoichio-
metry has changed little during the era of major
modification of upper-class undergraduate and
graduate curricula. Though "modernized" at
times by introduction of the digital computer to
assist in the solution of large problems, the course
content remains by-an-large the solution of steady
state mass and energy balances for existing pro-
cesses. Skills are haphazardly developed through
many example problems and little attention is
paid to the development of a consistent logical
approach to engineering problem solution. Recent
developments which have greatly improved and
expanded high school and university freshman
courses are ignored. The student's mathematical
skills are not adequately reinforced with practice
in engineering problems and almost no attention
is paid to his improved abilities in elementary
calculus and basic chemistry. In an attempt to
"simplify" problems for the sophomore level many
concepts, particularly in basic thermodynamics,
are introduced incorrectly and a re-learning must
take place in the courses which follow. Con-
siderations of design are never included because
the concept of a rate is usually not introduced.
The type of problem considered has little to do
with the creative aspects of traditional chemical


engineering practice or the extension of chemical
engineering skills to a broader class of problems.
The inadequacy of the traditional sophomore
course is compounded by the lack of continuity
between it and the "engineering science" courses
which immediately follow: There is a difference
in approach, type of problem, and analytical level.
The transition is a difficult one for many students,
and in 1965 the Chemical Engineering Depart-
ment at Delaware initiated a program to study,
modify, and if necessary, reorganize the intro-
ductory course in the curriculum. This study has
resulted in our present "Introduction to Chemical
Engineering Analysis" course, which meets the
following three objectives:
To reinforce, amplify, and apply in an engineering
environment the material covered in basic chemistry,
physics, and mathematics.
To develop the basic skills needed as a sound founda-
tion for upper level courses.
To develop an early appreciation for design by involv-
ing the student in simple but significant chemical
engineering design problems.
Because of the considerable discussion in the
profession about the proper direction for under-
graduate education it seems to us that it is useful
to recount our approach and the evolution of the
course and our thinking. We do this because what
seemed to us and many colleagues to be obvious
remedies for the deficiencies noted above were not
successful at all, and the final course outline
differs considerably in content and tone from our
first attempts. The course in its present form is a
result of some five years experience teaching the
subject to sophomore students in both the regu-
lar and extension programs. Some portions of
the material have also been used with engineers
and chemists who participated in AIChE con-
tinuing education courses at both the national
(Today Series) and local levels. For three years
we taught the course together at the same hour,
each with a section of about twenty-five students.
The material was coordinated on a lecture to
lecture basis and its impact on students was
evaluated after each lecture and again after each
major topic had been covered. Substantial stu-


SUMMER 1973
























T. W. Fraser Russell received the Bachelors and Masters
Degrees at the University of Alberta. He worked as a
research engineer for the Research Council of Alberta
and as a design engineer at Union Carbide Canada be-
fore receiving the PhD ('64) from Delaware. He is on
leave for 1972-73 at ETH Zurich. Professor Russell re-
ceived a University of Delaware Excellence in Teaching
Award in 1968. His primary research interest is on two
phase system analysis and design, and he has a book in
progress in the area. (left)
Morton M. Denn received the Bachelors Degree at Prince-
ton University and the PhD (64) at Minnesota. He has
been at the University of Delaware since 1964 and was a
Guggenheim Fellow in 1971-72. Professor Denn's major
research areas are the fluid mechanics and rheology of
polymeric liquids and optimization and optimal control.

dent feedback has been received, and several
undergraduates and graduate students have
worked with us for extended periods in evalua-
tion and revision. This method of teaching has
allowed us to experiment with various ways of
organizing and presenting the material, and we
feel that we have found a very effective way to
introduce students to chemical engineering.
In the first year, we taught a slightly modified
industrial stoichiometry course, followed by an
applied mathematics course which concentrated
on solutions of various types of differential equa-
tions encountered in chemical engineering. This
latter course replaced the more classical course
in differential equations taught by the mathema-
tics department. It quickly became apparent that
the major problem the student faced was develop-
ing the equations that described a particular sit-
uation. Since he did not feel adequately trained
in this skill, there was a strong tendency to sep-
arate the mathematical description and its be-
havior from the situation which it described.
This had two equally undesirable effects. Some
students concentrated on the mathematical mani-
pulation and thought little about the relationship


Today's curricula have been
justifiably criticized for failing
to teach applications of principles
and the new trend appears
to be a "return to design."

to the physical situation, while others became
confused as to the role of mathematics and tended
to dismiss the material as being an academic
exercise unrelated to physical reality. (This is
not unlike what has happened outside the Uni-
versity in professional practice. It has been our
experience in continuing education activities that
the greatest number of engineers who profess a
need for "more mathematics" are really in need
of a better understanding of model development).
In an attempt to overcome these serious prob-
lems and also to revise what we considered to be
inadequate or incorrect presentation in the stan-
dard stoichiometry course, we decided to restruc-
ture both courses and to concentrate on develop-
ing the skills which would enable the student to
see clearly the relationship between mathematical
description and physical reality. We attempted
to meet this goal the first time we taught the
integrated course by developing mathematical
models for a series of increasingly complex physi-
cal situations. This "case study" approach was
moderately successful and, although it did not


principles No Yes Matihernatical
foll""e"'ited o Enough equations? M
Fully exploited model


Constitutive
relation
Fig. 1. Model development for any physical situation.

CHEMICAL ENGINEERING EDUCATION










meet our goal of developing a systematic pro-
cedure for model development, the students did
develop some facility for seeing the proper role
of mathematics in the study of engineering.
The logic procedure outlined in Fig. 1 was
introduced on the third try at the course. We
emphasized this time the need for experimental
verification of constitutive assumptions, as dis-
tinct from the application of conservation prin-
ciples. This emphasis on the role of experiment
in engineering is, paradoxically, the key to a
student's understanding of the role of mathe-
matics. At this time we oriented the course to-
wards liquid phase reactor performance and con-
centrated on a complete study through design
using a single conservation principle (mass)
before introducing a second. We also found as
we progressed through the third year that it was
necessary to drop some of the mathematical skills
we had stressed so that the more important as-
pects of analysis could be properly covered. We
eliminated material on differential equations with
variable coefficients and reduced our discussion
of the Laplace transform.
An initial review of the third year's classroom
experience produced a course outline similar to
what now exists and pointed out a need for still
more emphasis on the experimental aspects of
engineering and the use of the mathematical de-
scriptions for simple design. Thus we decided once
more to reduce the mathematical content, result-
ing in total elimination of the Laplace transform.
(Students with the need for such mathematical
skills learn them in the senior Process Dynamics
and Control course).
We concentrated in our fourth year on better
organization of the material with respect to the
model development step in analysis and we reor-
ganized, using more experimental data, the
methods by which constitutive relationships were
employed. Our goal was to make sure that all the
relevant material normally covered in the stoichio-
metry course was introduced in a rational and
consistent manner. Since then the emphasis has
been mostly on polishing and minor changes.
The sophomore courses, ChE. 230 and 231,
are taught for two shortened semesters, totaling
twenty-seven weeks. The relationship of these
sophomore courses with other ChE courses at the
University of Delaware is shown in Table 1. Since
our students are not required to take a separate
course in differential equations, but rather study
the subject as part of the chemical engineering


Freshman
Year


TABLE 1 Basic Departmental Course Structure

Introduction to the
art and science of engineering

EG 125
(Introduction to Engineering)
EC 130
(Introduction to Engineering Research)


Sophomore Aquisition of the basic
engineering skill of Analysis--
Year How to proceed from experiment to design


Junior
Year









Senior
Year


ChE 230, 231
(Introduction to Chemical Engineering
Analysis)


The basic phenomena are studied from
an engineering viewpoint
Applied Physical Applied Chemical
engineeringg Sciences Engineering Sciences
ChE 341 ChE 325, 332
(Fluid Mechanics) (Thermodynamics
ChE 342 and Kinctics)
(Hoat and Mass
Transfer)
ChE 345 (Chemical Engineering Lab)


Skills are integrated by studying complex
engineering problems in class, in the labo-
ratory, and by individual thesis.
ChE 432 (Chemical Process Analysis-Design)
ChE 443 (Transfer Operations)
ChE 445 (Chemical Engineering Laboratory)
ChE 473,474 (Senior Thesis)
ChE 401,466,etc. (Electives in Control,
Pollution Abatement, Polymer Processing,
Chemical Economics etc.)


analysis course, a one-semester course employing
a major fraction of our outline is possible. Em-
phasis is on the analysis of liquid phase systems,
for this enables the student to treat meaningful
design problems during his first semester of engi-
neering study. He takes this course concurrently
with the final semester of calculus and two semes-
ters of physical chemistry. The topics covered
follow our book, Introduction to Chemical Engi-
neering Analysis, Wiley, New York, 1972.

INTRODUCTION. We start with a brief description of
three chemical engineering problems, where the emphasis
is on "putting together the pieces." We discuss a typical
chemical process, the manufacture of ethylene glycol; the
operation of an artificial kidney; and the design of a bio-
oxidation reactor for sewage treatment. This introduces
the idea of reactor, separation process, etc. We then turn
to a detailed study of the analysis process, which we
define as follows:

1) Description of a physical situation in mathematical
symbols.


SUMMER 1973









Student response has been excellent ...


2) Manipulation of the mathematical model to deter-
mine expected behavior of the physical situation.
3) Comparison of the model with the true physical
situation.
4) Careful study of the limitations of the mathema-
tical model.
5) Use of the model for equipment design and pre-
diction of performance.
ANALYSIS. Several days are spent discussing the basic
concepts involved in analysis and the total analysis
process is described by means of the simple example of
an emptying tank.
The model development step is illustrated using real data
to develop a relationship between outflow and height of
liquid (the orifice equation). Next the laws of conserva-
tion of mass, energy, and momentum applied to a
well-defined control volume are shown to be the basic
source from which mathematical descriptions are de-
rived. A careful distinction is made between general
conservation principles, universally applicable, and spe-
cific constitutive relations applicable only to certain
situations. The necessity of experimental data for the
development of constitutive relationships is stressed and
dimensional analysis is introduced as one means for
planning this needed experimental program. A series of
logical procedures is developed to show the student how
mathematical descriptions for a physical situation are
developed. The ultimate logic is shown in Figure 1.
NON-REACTING LIQUID SYSTEMS. Model develop-
ment for well-mixed tank-type liquid systems in transient
and steady state isothermal operation is illustrated in
detail, with an experimental check of the perfect mixing
assumption and a critical appraisal of the role of the
density-concentration constitutive equation. The purpose
is to give the student practice in the model development
step of analysis with simple problems, so that he can
clearly see the relationship between the mathematical
description and the physical situation. The simpler aspects
of basic calculus are employed to determine model be-
havior and, as a secondary aim, practice with manipula-
tion of the mathematical description to determine model
behavior is stressed. As one example to meet this latter
aim we exploit the draining tank problem and design a
simple feed back controller. This also shows the student
something about the design aspect of analysis.
REACTION RATE. Reacting, well-stirred single phase
liquid systems are studied next. The reaction rate arises
naturally in the component mass balance and reasonable
phenomenological forms are deduced. Emphasis is on the
use of batch reactor data to determine the validity of
constitutive assumptions for the rate and to find the
values of the parameters. Real batch data are used in all
cases.
REACTOR DESIGN. The steady state model equations for
a well-stirred continuous flow reactor are used for two
design problems. In the first, a reactor is sized to meet
production requirements for a single, irreversible first
order reaction, taking capital and operating costs and


depreciation of the reactor and separation unit into
account. (The economics are obviously simplified). The
other is the problem of sizing a reactor to obtain a
required distribution of mono-,di-, and tri-ethylene glycol
(a process introduced earlier). The sophomores take
this material nicely in stride and take pride in their
ability to use the mathematical descriptions. We intro-
duce the plug flow tubular reactor here for comparison.
MASS TRANSFER RATE. Two-phase, well-stirred sys-
tems are studied to introduce the concept of mass trans-
fer and to further develop modeling skills. The rate of
inter-phase mass transfer arises naturally in the com-
ponent balances and, like the reaction rate, reasonable
phenomenological forms are deduced. Batch data are used
to study the approach to equilibrium. For a continuous
flow process the equilibrium stage is shown to be a good
approximation for typical mass transfer data. Stage
efficiency and reaction in a two-phase system are briefly
examined.
STAGED PROCESSES. Multistage solvent extraction is
studied analytically and graphically (McCabe-Thiele).
Calculations are done for minimum solvent requirements
and numbers of ideal stages. The triangular diagram is
used for single stage calculations. The material nicely
illustrates the use of graphical techniques in the model
behavior step of analysis.
This is roughly the end of our first semester, together
with some mathematical topics as needed, including least
squares fitting to data. The student deals routinely with
dynamical situations as well as the steady state, but he
never requires mathematical concepts not already used
in his calculus course. The interplay between laboratory
experiment (measuring reaction rates, mass transfer co-
efficients, equilibrium constants, etc.), mathematical
modeling, and engineering design calculations is brought
home. This works because there is simply no easier
practical problem in chemical engineering than the sizing
of a liquid phase reactor with uncomplicated chemistry.
The student is motivated to go on to engineering science
courses and learn, for example, why a mass transfer
coefficient is of a given order, or how to estimate one in
the absence of an experiment. Most important, he has
learned a systematic approach to solving problems.
At this point we turn to non-isothermal systems. In
some curricula it might be desirable in a one semester
course to skip some or all of the material on mass trans-
fer processes and include some of the non-isothermal
material. Emphasis is on the operational definition of
thermodynamic quantities and, to avoid the complication
of compressibility, liquid phase systems are studied first.
CONSERVATION OF ENERGY. Internal energy is in-
troduced and the principle of conservation of energy
applied to a flowing system. The square root orifice equa-
tion is derived using the energy balance. Internal energy
and enthalpy are related to temperature by defining the
heat capacity. Partial molar enthalpy is defined and used
to define the heat of solution and the heat capacity of
a mixture. Students are prepared to deal with partial
molar quantities at this level because it comes sufficiently
soon after seeing partial differentiation in the calculus
course.


CHEMICAL ENGINEERING EDUCATION









The student is continually referred back to relevant sections of his calculus and chemistry texts, developing, in
his eyes, a logical continuity between his basic science courses and creative engineering. Physical
chemistry laboratory experiments are often discussed in our classroom.


MIXING AND HEAT TRANSFER. In parallel with the
isothermal system development, we model non-reacting
liquid systems. Consideration of temperature effects in
batch mixing is followed by construction of the enthalpy-
concentration diagram and graphical solution of the same
problems. This is then repeated for steady state con-
tinuous mixing. The analysis of mixing is done rigorously,
using partial molar enthalpies, for otherwise the student
learns incorrect procedures which ensure the wrong
answer when working with multi-phase systems. Heat
transfer between adjacent chambers leads naturally to
the rate of heat transfer and definition of the heat trans-
fer coefficient. Area and flow rate calculations are carried
out for cooling a tank by a jacket and a coil.
REACTING LIQUIDS. Reacting liquid systems are dealt
with after the student has seen how partial molar quanti-
ties are used in the simple mixing situation. The heat of
reaction is defined in terms of the partial molar enthalpy
and the batch reactor equations derived which demon-
strate how to measure it. Calculation of the heat of
reaction from tabular data is discussed. The Arrhenius
temperature dependence of reaction rate is demonstrated
and the transient adiabatic batch reactor equations for a
single reaction are integrated using numerical quadrature.
(This still requires only the calculus course as prepara-
tion.) The energy balance for a continuous flow stirred
reactor is derived. A numerical solution of the steady
state is obtained, and the qualitative behavior of the non-
isothermal reactor is discussed using the Van Heerden
slope argument and phase plane construction via the
method of isoclines. The non-isothermal tubular reactor
is touched upon very briefly. By this point the student is
becoming quite skilled in making his mathematical skills
work for him to understand physical problems.
TRANSIENT REACTOR BEHAVIOR. We include this
material as the practical application for linear differential
equations, which are included in the course. The section
can be omitted without serious loss. The reactor equa-
tions are linearized in the neighborhood of the steady
state to obtain a linear second order system with constant
coefficients. Applications are to the stability of the steady
state, response of a stable system to a feed disturbance,
and proportional feedback control by coolant flow rate
adjustments. Students have no trouble with the notion
of linearization. They have seen a number of examples
in which the physical problem is severely limited in order
to obtain a tractable mathematical model, and they
recognize the virtue and limitation of such a trade-off.
GAS SYSTEMS. To show that analysis skills can be
readily extended we deal with gas systems as a final topic.
Non-reacting and reacting batch systems are re-examined
with the compressibility term retained in the energy
equation. Constitutive equations are introduced for the
ideal gas and several non-ideal gases and the compres-
sibility chart and mixing rules are introduced.


MATHEMATICS. At appropriate times we cover numeri-
cal methods for solving algebraic equations, and, towards
the end of the course, analytical solution of linear, non-
homogeneous differential equations with constant co-
efficients and elementary numerical solution of nonlinear
differential equations.
Student response to the course has been excel-
lent. We feel, with some pride, that this is at least
in part a reflection of the course content and
organization, particularly chemical engineering
courses seem to the student to be a natural out-
growth of the analysis course. There is another
factor, however, which helps considerably. The
student is continually referred back to relevant
sections of his calculus and chemistry texts, de-
veloping, in his eyes, a logical continuity between
his basic science courses and creative engineering.
Physical chemistry laboratory experiments are
often discussed in our classroom. This blending
is in stark contrast to the nearly total discontinu-
ity which existed under the old program.
Colleagues unfamiliar with the details and
student performance often express concern over
the level of material and wonder whether sopho-
mores can really handle it. Our emphatic "yes"
supported by formal AIChE student chapter and
Student Government Association evaluations, is
most easily justified by a related fact. Last year
we introduced a course for non-majors based on
our first semester course. We will discuss that
course in detail at another time, but it is quite
similar in content and level to the first semester
course for chemical engineering majors. We have
had participation from students to biology, chem-
istry, economics, home economics, and secondary
education, among others, some of whom have
studied no chemistry. Registration went from
eight in the first year to thirty-two in the second,
and the course is recommended now by the chem-
istry department for its undergraduate majors.
The students rated the course 4.7 out of a possible
5.0 in the SGA evaluation. It is clear from the
performance of the non-engineers that our engi-
neering procedures for problem solving are appre-
ciated by a much larger portion of the student
body than we originally anticipated. When the
concepts can be grasped by non-majors, it is evi-
dent that the material belongs at the sophomore
level in a Chemical Engineering curriculum.


SUMMER 1973









*1-t16haip


THE UNDERGRADUATE CHE LABORATORY*


H. S. FOGLER', A. J. PERNA2, and
F. H. SHAIR3


The laboratory workshop format consisted of
a number of speakers each discussing a particu-
lar aspect of a laboratory. The papers presented
can be classified in four categories: 1) the phi-
losophy and objectives of the laboratory, 2) com-
puter aided laboratory instruction, 3) types of
laboratories and experiments, and 4) different
approaches and instructional techniques. To
assess the attitudes of laboratory instruction
along with current and future trends in each of
the above categories, a 10-page questionnaire was
prepared and mailed to over 50 chemical enge-
neering departments (primarily those who had
faculty members registered for this workshop) in
the U. S. and Canada and to a significant number
of industrial contacts.

I. PHILOSOPHY AND OBJECTIVES
The major results of the survey were dis-
cussed in the first paper of the session by H. S.
Fogler. The consensus indicated that the most im-
portant goals of the laboratory were to
* Demonstrate or reinforce principles or phenomena
discussed in class,
* Give the students practice in planning and interacting
with the experiment,
* Develop the students' interest in experimentation,
* Develop a proficiency in technical report writing, and
* Expose the student to open-ended experiments of a re-
search or design nature.
Information on the philosophies of the laboratory
at various universities along with ideas about
experiments which impart a sense of learning to
the student and leave him with a sense of accom-
plishment were also summarized in this paper.
The results of one question, when averaged,
showed the following allocation of the student's
time currently spent on a given experiment.

1. The University of Michigan, Ann Arbor, MI 48104.
2. Newark College of Engineering, Newark, NJ 07102.
3. California Institute of Technology, Pasadena, CA
91109.


15% of the time should be spent in preparation for the
experiment
30% should be used for setting up and carrying out the
experiment
25% should be spent on computation and analysis for
the raw data
30% should be used for writing the report on the ex-
periment.
Many felt that too little time was currently
being spent on giving the students practice at
planning and interacting with the experiment to
learn the process of experimentation, i.e., the
technical and managerial skills required to carry
out effective experiments. In the future, it is
hoped that most laboratories will provide the
student with the opportunity to plan meaningful
experiments and experimental programs in which
the outcome is not known or is uncertain and in
which one must allow for contingencies.
Also discussed in the first paper were a few
techniques used at The University of Michigan
to complement the standard laboratory exercises
in order to increase the student's capabilities for
planning effective experiments. In particular, the
use of guided design instruction in the synthesis
of experimental projects at the sophomore level
has proven quite effective. Here, a group of 3-4
students (1) define and develop the need for an
experiment which they would like to perform, (2)
state the constraints on the experimental pro-
gram (3) determine the key or critical measure-
ments to be made, (4) suggest methods of pro-
cessing and analyzing the data, (5) support alter-
nate approaches to various segments of the proj-
ect, (6) suggest possible outcomes and means of
evaluating the effectiveness of the programs.
Each group receives feedback from the instruc-
tor at various stages of the planning and then
gives an oral presentation and defense to the
other groups at the end of the semester.
Methods of implementing the open-ended
approach laboratory were presented by R. Clift
and 0. M. Fuller. They described a ChE Labora-
tory course at McGill, in which a special format
*Report on the Undergraduate Laboratories Workshop at
the ASEE Summer School in Boulder, CO 1972.


CHEMICAL ENGINEERING EDUCATION






















Shair


Fogler


called the Evolutionary Laboratory has been de-
veloped in order to place emphasis on the process
of experimentation itself. The distinctive features
are specialization of the staff for optimal use of
teaching personnel, and the conference period for
rapid feedback and evaluation.
Work on each unit of apparatus is directed by
an experiment controller (EC) who acts both as
technical expert and teacher. The EC has suffi-
cient freedom in planning so that he may, for
example, direct a logically connected sequence of
experiments rather than repetitive exercises. Fol-
lowing each laboratory exercise, the students have
a conference with the EC which consists of an
oral report, a teaching session, and an occasion
for feedback on instructions and apparatus. The
conferences permit flexible planning and evolu-
tionary changes in the exercises. The teaching of
experimentation requires, among other things, a
description of the process in terms of observable
behaviors and a methodology for planning ex-
periments. For this purpose, the McGill program
offers a description in terms of instructional ob-
jectives and an extension of PERT for planning.
In addition to comments on the laboratory
received from industry on the questionnaire, in-
formation was gathered and presented by Drs.
C. C. Zimmerman and D. N. Burdge of Marathon
Oil Company who view the laboratory as a tool
to increase the student's problem solving capabili-
ties through experimentation. They reinforced
earlier presentations suggesting that greater
emphasis be given in the laboratory to problem
definition and analysis and to experimental plan-
ning. This is to help insure that the student or
employee may learn to decide which measure-
ments will be meaningful and not to carry out
unnecessary experiments whose results could have


been obtained by other means, such as a combina-
tion of reasoning and calculation. They encour-
aged greater development of the student com-
munication skills primarily through report writ-
ing but also through oral reports to the instruc-
tor. It is interesting to note that while only 50%
of the universities returning the questionnaire
stated that report writing was a major objective
of the laboratory, every industrial reply suggested
that improvement in the students report writing
should receive major attention.

II. TYPES OF LABORATORIES AND EXPERIMENTS
F. H. Shair reported the survey results con-
cerning the attitudes expressed by ChE faculties
towards the laboratories in chemistry and physics
which are required by students who enroll in the
ChE curriculum. Generally the ChE faculty were
satisfied, but certainly not enthusiastic about the
chemistry laboratories. On the other hand, the
ChE faculty generally expressed moderate dissat-
isfaction with the physics laboratories. Over half
of the persons answering the questionnaire stated
that they believed their required physics labora-
tories to be of little value in aiding their students
in developing important laboratory techniques, in
helping their students to analyze experimental
error and uncertainty, in helping their students
develop report writing, in helping their students
develop oral presentations, and in helping their
students formulate an experimental path aimed
at obtaining desired answers with the least effort.
The merits of the undergraduate laboratories de-
veloped by E. C. Stone and D. W. Skelton at
Caltech discussed in some detail.
Professor Shair also described a ChE inte-
grated concepts and laboratory course which has
been given during the last five years at Caltech.


SUMMER 1973








The fundamentals of ChE are emphasized along
with both oral and written presentations. The
laboratory experience involves open-ended proj-
ects which are also of interest to someone outside
of Caltech. Recent experimental topics involved
the internal combustion engine, the melting of
icebergs, the spreading of oil slicks, the decay of
ozone within buildings, transport across pul-
monary membranes, and transport across artifi-
cial kidney membranes. Students participate in
the planning as well as in the conducting of ex-
periments. Several projects are in some stage of
being published in the open literature. Exams
are given in the form of scenarios. The most im-
portant aspect for course update and improve-
ment involves the recycle of the top 10% of the
class into teaching assistants during the follow-
ing year.
Discussed by A. J. Perna were those results
of the 10-page questionnaire relating to the Unit
Operations Laboratory. A summary of the over
thirty schools responding showed that:
All had either conventional Unit Operations Labora-
tory or a Transport Laboratory;
Laboratory experience ran the gamut from a three
level approach (sophomore-junior-senior) to only
a senior year (majority) course;
Laboratories were primarily hardware rather than
computer oriented;
In general, laboratory experiments were a blend of
pilot plant size and transport size;
Integrated Lab-Theory courses were rare with only
approximately 18% of the schools using this
approach;
All schools have experiments designed to cover the
areas of Heat, Mass and Momentum Transport
in their Unit Operations Laboratory, but some
schools also have incorporated experiments in
kinetics, thermo and process control and dynam-
ics in the lab;
In general the lab improvements have been in the
areas of instrumentation, open-ended experimen-
tation, and reduced workload.
One important factor which came out of the sur-
vey was that the laboratory has become an area
for exposing the students to concepts not taught
in the classroom and that it is an extension of his
learning process and not completely integrated
with the material presented in theory type
courses.
R. D. Williams described a one hour chemical
reaction engineering laboratory currently being
used at The University of Arizona. In this labora-
tory the student is exposed to a number of differ-
ent types of reactors used in homogeneous liquid


Many felt that too little time was spent
on giving students practice at planning and
interacting with the experiment ...



phase reactions, in catalytic heterogeneous re-
actions and in non-catalytic heterogeneous re-
actions. A number of methods of data collection,
ranging from direct sampling and titration or
gas chromatography to direct temperature and
pressure measurements, are illustrated in the
course along with different methods of data an-
alysis. The students could use these reactors to
carry out reactions whose rate laws have been
reported in the literature or to study reactions
whose kinetics have not been reported.
An alternative to the weekly laboratory in the
form of a three-week intensive course was pre-
sented by G. B. Williams and J. H. Hand of The
University of Michigan. In this course, which is
offered at the end of each winter term, the stu-
dent has essentially an entire day to complete the
experiment and write his report. Consequently he
is not under the usual pressure to get the experi-
ment working and finished within as soon a time
as possible in order to rapidly go on to other
course assignments. In the intensive course there
is adequate time to modify and experiment with
the equipment, and also time to profit from rou-
tine difficulties and breakdowns of the equipment.
While the faculty and students are equally en-
thusiastic about conducting the course in this
manner, the only two serious drawbacks appear
to be centered around finding housing for the
students for only three weeks after the end of
the term and the lab's interference with some
summer jobs and summer school.
R. M. Hubbard presented a pilot plant oriented
experiment which students undertake as a final
experiment in the ChE laboratory at the Uni-
versity of Virginia. The experiment is multi-
purpose and forces students to work as a team
to take data, make material balances on a process
as soon as data are obtained, and to experience a
continuous operation such as might be encoun-
tered later in industry. A small operating chemi-
cal plant produces hydrogen and carbon dioxide
from the catalytic decomposition of a vaporized
methanol-water mixture at 300'C and atmos-
pheric pressure. The students operate the plant
in shifts for most of a normal day and acquire
enough data to carry out at least two complete
material balances per shift.


CHEMICAL ENGINEERING EDUCATION









III. COMPUTER AIDED LABORATORY INSTRUCTION
D. E. Seborg described the computer-aided
student laboratory which he and D. G. Fisher
have developed during the last five years at the
University of Alberta. The computing facility in-
cludes an EAI 590 hybrid computing system
plus an IBM 1800 digital computer which oper-
ates in a multi-programmed, time-shared mode
and allows several research workers and student
laboratory groups to have simultaneous, open-
shop access to the real-time and background com-
puting facilities. Typical real-time applications
include control of pilot-plant processes, automa-
tion of analytical instruments, and student
oriented experiments designed to demonstrate
particular hardware and/or software features.
It was stressed that when properly used, the
computer can take over the time consuming
routine tasks and let the student concentrate on
the important, fundamental concepts of the ex-
periment.
R. A. Schmitz described the on-line computing
facility for undergraduate instruction which he
has developed during the last three years at the
University of Illinois. The system utilizes a time-
sharing IBM 1800 computer in conjunction with
an undergraduate process dynamics and control
laboratory. The apparatus connected to the com-
puter constitute simple closed-loop systems for
studies of mathematical modeling and direct digi-
tal control. Students using the system must write
a FORTRAN program to handle the collection of
data, the sending of feedback signals and any
calculations involved in the data processing. The
system also provides for the connection of an EAI
580 analog computer to the digital machine so
that the computer control of complex systems
may be simulated. The facility is being employed
in a required undergraduate course on process
dynamics and control and in an undergraduate
projects course.

IV. DIFFERENT APPROACHES AND INSTRUCTIONAL
TECHNIQUES
An integrated theory-laboratory course ap-
proach was described by R. R. Furgason of the
University of Idaho. The approach is to block
out from four to six hours per week for a sched-
uled three credit course and have the class meet
in a lecture mode for several weeks followed by
one or two weeks of class devoted to laboratory
experimentation. This allows the laboratory to
be utilized whenever appropriate rather than on


An integrated theory-laboratory
course was described .. This allows
the laboratory to be utilized
when appropriate rather than
a fixed schedule.

some fixed schedule. The main advantage is the
excellent coordination between theoretical and ex-
perimental phases of the class with the laboratory
neither leading or lagging the course. The dis-
advantage is primarily logistical in terms of class,
manpower, and scheduling.
The integrated laboratory-lecture approach is
being carried out on a much larger scale at Wor-
cester Polytechnic Institute, where it encom-
passes the entire curriculum. Professor I. Zwiebel
discussed the WPI project approach in which
courses are viewed as elective tools to build the
foundations for completing the students two
major projects, which are the primary require-
ments for graduation along with a competency
examination and a humanities minor. Many proj-
ects are inter-disciplinary in nature and require
a team of students (e.g., a civil engineering-
chemical engineering, etc.) each with his particu-
lar responsibility, working together to obtain a
solution. Special projects, sponsored by a Sloan
Foundation grant, run through about 1 1/3 cal-
endar years during which time the student's time
is divided equally along the following four seg-
ments of the project: preparing a proposal of
the project plans, executing the plans, analyzing
the results, and preparing written and oral re-
ports. The WPI project approach offers a sig-
nificant alternative to the conventional engineer-
ing programs.
J. 0. Maloney and G. M. Kortman of the Uni-
versity of Kansas presented material on two in-
structional laboratory units. The first was con-
cerned with an experiment in unsteady-state-cool-
ing, while the second unit treated the determina-
tion of binary vapor-liquid equilibrium data
using an Othmer still. Especially developed for
inexperienced instructors, each unit contains
sufficient material that the instructor, after read-
ing it and doing the experiment once or twice,
would have adequate control of the experiment
and would be able to estimate the validity of
student results. Each unit provides the following
information: equipment description, experimental
procedure, extensive data, calculations, computer
programs, error analysis, and suggestions for
modification of the experiment to achieve variety.
(Continued on p. 135)


SUMMER 1973










.1ectwe .%emanondataon


BERNOULLI'S EQUATION WITH FRICTION


NOEL DE NEVER
University of Utah
Salt Lake City, UT 84112

This demonstration shows examples of flows
in which inertial effects are greater than fric-
tional effects and the converse. These are ex-
plained in terms of Bernoulli's equation with
friction.

APPARATUS
The apparatus consists of:
1. A one-gallon solvent can, into which a 14" IPS
coupling is soldered near the bottom.
2. A one-foot length of 1/" IPS pipe with five 14"
OD holes drilled in it on 2" centers. These holes are all
aligned on one line in the pipe surface, parallel to the
pipe axis. Both ends of the pipe are threaded.
3. Same as No. 2, except that into each of the five
holes a long piece of /4" OD copper tubing has been
slipped and soft-soldered in place.
4. A piece of 1", rod, 12" long.
5. A 1,4" IPS pipe cap.
6. A short length of rubber tubing.
7. One gallon of water thickened with 1.0 wt%$
Methocel 4000, estimated viscosity 100 to 150 cp.

DESCRIPTION OF DEMONSTRATION
1. The instructor sets the can on the lab bench over
a sink, with part No. 3 inserted in the coupling and the
end of No. 3 covered with the cap (No. 5). He shows it
to the class, describes it to them, and tells them he is
about to fill the can with water. He asks them to predict
which jet from the pieces of tubing will rise the highest.
After taking a poll of the class, he fills the can (using
the rubber hose). The water jet squirts highest from the
tube farthest from the can and successively lower from
the tubes nearer to the can.
2. The instructor then removes the cap from the end
of the pipe, inserts the rod, replaces the cap, and tells
the students that he will again fill the can with water.
He again asks which jet will go highest and records the
results of his poll. He then fills the can with water. This
time the water squirts highest from the tube nearest the
can.
3. The instructor removes the rod from the tube and
tells the students that he is about to fill the can with
the methocel solution. Again he takes an opinion poll on
which jet will go highest. He then pours the solution into
the can. The jet nearest the can squirts highest, but none
of the jets squirts as high as in demonstration No. 2.


4. The instructor then removes part No. 3, rinses the
can, and replaces part No. 3 with the pipe which has only
holes (part No. 2). He tells the class that he is going to
fill the can with water and again quizzes them as to which
jet will go highest. After recording the predictions, he
fills the can with water. This time there is a hump-shaped
distribution of heights, with the highest in the middle.
The streams are very unequal in width, with the stream
nearest the can the thinnest and the far stream the
thickest. The streams are not vertical, as before, but
leave the holes at an angle away from the can, with the
stream nearest the can about 100 from the vertical and
the stream farthest from the can about 30 from the
vertical. It is also observed that each of the streams
uses only part of the hole to exit through, and that part
is the part farthest from the can. The near hole issues a
stream which fills about one fifth of the hole area; this
fraction grows to about three fourths at the far hole.
5. The instructor explains the foregoing experimental
results.

THEORY
For the first three demonstrations with the
fluid rising through the small vertical tubes, the
flow (and, hence, the height to which each jet
rises) depends only on the static pressure at the
base of the vertical tubes. The sharp right-angle
turn which the fluid makes entering these tubes
prevents any of the horizontal momentum of the
fluid from being converted into vertical momen-
tum.
To find the pressures at the base of these
tubes, we apply Bernoulli's equation:

A + gz + = F ()
Here states 1 and 2 are chosen as shown in
Figure 1.

COPPER
TUBES I
Lo I fCAP
FLOW n',{


PIPE


Figure 1.


CHEMICAL ENGINEERING EDUCATION























W t~iS
Noel de Nevers earned his BSChE at Stanford and
his PhD at the University of Michigan, with a year out
in between to be a Fulbright exchange student at the
Technical Institute in Karlsruhe, Germany. He spent five
years with what is now Chervon Research and Chevron
Oilfield Research, before joining the faculty of the Uni-
versity of Utah. He spent Academic 1971-72 on leave,
working for the Office of Air Programs of the Environ-
mental Protection Agency. He is the author of a text-
book on Fluid Mechanics, and editor of a book of readings
and discussions on Technology and Society.

From 1 to 2 there is no change of elevation or any
pump work done on the system, and V, is zero; so
p P V2
2 1 = F (2)
p 2
Substituting for F from the Fanning friction fac-
tor equation (1) and solving,
2

Equation 3 indicates that if 4f L/D is less
than 1, the static pressure at 2 will be greater
than at 1; and, if 4f L/D is greater than 1, the
static pressure at 2 will be less than at 1. Thus,
by adjusting the value of 4f L/D, one can cause
the water to squirt highest from either the far-
thest or nearest tubes.
This analysis is not restricted to the two end
holes. It can be applied to holes n and (n+-1),
yielding
P P V2 V2
n + 1 .n + n 1 s4f L +(4)
P P 2 Dj DI 2
Here V, is always greater than Vn,+i; so, if f 0,
P,,+i is always greater than Pn. Thus, for any
two holes, the relative jet heights are determined
by the value of (1 4f L/D) between them.
In experiments run as described above, with
the can held full of water so that the flow was at
steady state, it was found that, with no rod in
the pipe, the flow rate out of the farthest tube was
1000 cc/min; the Reynolds number in the pipe


just upstream of it was about 104. If we accept
the value of e for galvanized pipe from Perry'
as 0.006 inches, then we can read f=0.012, which
makes 4fL/D equal 0.27. We would expect the
fluid to squirt highest from the farthest tube, as
it does.
In a similar experiment, with the 0.25" OD
rod in place, it was found that the flow rate from
the near tube was about 550 cc/min. By using
the hydraulic diameter, as shown in Perry', we
can calculate the Reynolds number as 2 x 104.
Using the same absolute roughness as before
yields f=0.018 4f L/D = 1.25. This indicates that
the fluid would squirt highest from the nearest
tube, as it does.
Raising the water viscosity has the same effect
as inserting the rod. The flow is laminar, and the
friction factor is proportional to the viscosity.
For the thickened water, the friction factor is
large enough that 4f L/D is greater than one;
and the water squirts highest from the hole near
the can.
The whole subject of flow in this type of mani-
fold has been reviewed by Acrivos et al.2
The fourth demonstration is much more com-
plicated to explain than the first three because
there is no simple, one-dimensional representa-
tion of this flow. If we had placed a pitot-type
tube in each of the holes, with its exit vertical,
we would expect that from each hole the jet
would have risen the same amount if friction
were negligible. This result would have been the
same, even if the various pitot-type tubes were
of different diameters. If, however, we had tilted
the exits of these pitot-type tubes at differing
angles to the vertical, the heights of rise of the
jets would not have been equal because, at their
highest points, the jets would have had varying
kinetic energies in the horizontal direction.
In the fourth demonstration, the fluid forms
its own pitot tubes. The wall thickness of the pipe
is only about one third of the hole diameter, so
the fluid can turn through the hole without losing
all its horizontal momentum. The interesting
thing here is that, the faster the fluid is flowing,
the greater is the angle through which the fluid
must turn to exit; so the fastest-moving fluid
exits nearest the vertical. One may look at this
another way by saying that the fluid builds up a
turning vane for itself, made up of stagnant fluid
trapped in part of the orifice.
This conversion of horizontal to vertical mo-
mentum is not perfect, so the jet nearest the can


SUMMER 1973









does not rise as high as it would if the conversion
were perfect. As we proceed out the pipe, we see
two conflicting effects producing the hump-shaped
distribution:
1. The increasing efficiency of the "turning
vanes" as the velocity falls leads to higher rise;
and
2. As the angle through which the fluid must
turn to exit decreases, the fluid exits more nearly
horizontally and thus does not rise as high.

A VARIATION
For graduate courses, one may insert a 5/16"
thin-wall tubing about 10" long, open at both
ends, into the pipe in place of the rod. In this
case the flow through the tube will be great
enough that the two end jets will both rise higher
than the ones in the middle. This presents an
analysis problem suitable for graduate students.

SOME PRACTICAL CONSIDERATIONS
1. The pipe connections should be finger tight. A
small leak doesn't hurt.
2. In placing the copper tubes in the holes in part
No. 3, little care is needed to align them. After they have
been soft-soldered in place, they can be easily bent into
line by holding the pipe in a vise, inserting a steel rod
in each tube, and tapping it gently into line with a
hammer.
3. To make the pipe without the tubes (part No. 2),
use extreme care to get the holes in one axial line.
4. While running the experiments, tilt the plane of
the orifices a few degrees to one side (by rotating the
pipe) so that the jets fall free of the pipe and do not
interfere with each other.
5. Check the apparatus carefully for burrs. They can
have a pronounced influence.
6. In running the first part of the experiment, it is
well to show that the result is independent of which end
of the pipe is inserted in the can. As long as all the con-
nections are finger tight, the instructor can reverse the
position of the pipe in the can quite quickly.
7. Allow adequate time to make up methocel solu-
tion. Sugar solutions could be substituted, but they are
messy. Any viscous solution will do, but methocel is prob-
ably the cheapest and easiest.

ACKNOWLEDGMENT
This device was used by Dr. J. Q. Cope, former vice
president of the Chevron Chemical Corporation, to teach
young engineers several important lessons. His procedure
was:
1. Describe the apparatus to the new engineer, with-
out mentioning the insertable rod.
2. Ask him from which end of the pipe the jet will
squirt highest.
3. When he answers, goad him into betting that he
is right.
4. Go get the device, inserting the rod if necessary.


5. Demonstrate-and take his money.
The educational qualities of this procedure are ob-
vious.

NOMENCLATURE


diameter
Fanning friction factor.
lost work per pound due to friction
acceleration of gravity
length
mass
pressure
velocity
pump work
elevation
absolute roughness
density


ft

ft-lbf/Ibm
ft/sec2
ft
Ibm
lbf/in2
ft/sec
ft-lbf
ft
ft
lbm/ft3


REFERENCES
1. Perry, J. H., et al. Chemical Engineers' Handbook
(4th Ed.; McGraw-Hill, 1963), p. 5-19 et sec.
2. Acrivos, A., B. D. Babcock, and R. L. Pigford,
'Flow Distributions in Manifolds," Chem. Eng.
Science. 10 (1959), pp. 112-124.


BOOK REVIEW: (Continued from p. 110)

Atom balances, purge and recycle are not dis-
cussed. Although reactors form a central theme;
conversion, yield and extent of reaction are not
used or defined. The enumeration of the number
of equations (mass balances, mass fraction con-
straints) does not appear, for this text does not
deal with multi-unit processes in multicomponent
systems.
The mathematical content is such that a stu-
dent should have finished calculus and differ-
ential equations. Parenthetically, the student is
asked to deal with a large amount of notation to
appreciate the content. Computer methods are not
stressed, although there is material on numerical
methods. Any computer applications would re-
quire a supplementary text. Linear algebra, which
some people refer to as "the language of stoich-
iometry," is not used.
In short, one must compliment the authors on
their attempt to inject vitality and meaning into
the first text in chemical engineering. However,
their approach does not fit well in a so-called
"standard" core curriculum. Perhaps our curricu-
la will adapt: I for one concur with their phi-
losophy. For the present, the book will find use
in peripheral ways, such as refresher courses.

ROBERT H. KADLEC
UNIVERSITY OF MICHIGAN


CHEMICAL ENGINEERING EDUCATION










THE CHE DESIGN LABORATORY


HARRY SILLA
Stevens Institute of Technology
Hoboken, N. J. 07030

A new design program for senior-undergradu-
ate chemical engineers was initiated at Stevens
Institute of Technology in the 1968-69 academic
year. One important feature of the program is
the use of the ChE laboratory as a vehicle for
teaching design. Because of the emphasis on de-
sign, this laboratory is called the ChE design
laboratory. This paper discusses the philosophy
and organization of the laboratory.

PHILOSOPHY AND OBJECTIVES
A recent report* gives the distribution of
chemical engineers according to areas of speciali-
zation. As one would expect, no one category pre-
dominates. For this reason it does not seem rea-
sonable to place the emphasis in design educa-
tion entirely on process design. In order to obtain
a broader and more flexible program in design we
have added the ChE design laboratory to our
course to complement process design. Besides
giving a student who is interested in process de-
sign a broader view, the design laboratory also
gives the student experience in project engineer-
ing and the design of experimental systems for
research and development. Furthermore, one of
the most valuable experiences any young engi-
neer can obtain is to follow a project from its con-
ception through it design stages and finally reduc-
tion to practice. The design laboratory gives the
student this opportunity.
The importance of design in research and de-
velopment needs further discussion. An engineer
working in this area must frequently design his
own apparatus, and he must usually show results
within a year to justify the continuation of a re-
search project. A considerable amount of valuable
research time may be wasted due to errors in the
design of apparatus. There are many unpredict-
able factors in a research project that one cannot
afford to be held back by errors in design. Prob-
ably, some of the recent disenchantment with re-

*Roethel, D. A. H., Counts, C. R., Realignments in the
Chemical Profession Continue, p. 90, Nov. 15, 1971.


search productivity can be traced back to avoid-
able delays caused by poor equipment design. At
any rate, the one way a research engineer can
increase his productivity is by becoming a skilled
designer of equipment. The importance of design
in research and development is generally over-
looked.
ANATOMY OF A PROJECT
Each student is interviewed and assigned a
project according to his interest and ability. The
process begins by having each student make up a
resume of his experience, skills and career ob-
jectives. After the interview the students are
formed into teams which consists of a maximum
of three students. Teams of two students are
optimum, but economics requires that many three-
man teams be formed.
We are willing to undertake many types of
projects. Our only requirements are that the
project is useful; that someone can be found who
is knowledgeable in the area to act as an advisor
for the project; and that the project can be com-
pleted at a reasonable cost. A project may involve
designing a completely new apparatus or design-
ing an improvement or addition to an existing
system. It should be emphasized that an important
objective of the design laboratory is that the stu-
dents develop the skills required to reduce his
design calculations to practice. It is one thing to
make design computations and another thing to
translate these computations into a working sys-
tem. A typical project involves a) definition of
the problem b) design calculations c) evaluation
and purchasing of equipment d) assembling the
apparatus e) testing and trouble shooting f) col-
lecting correlating data g) and writing the final
report.
The student is usually given the objectives
of his project in a general way. To help define the
problem students are required to search the litera-
ture and read several articles to become familiar
with the theory and experimental details.
Since the design laboratory involves many
different projects, much of the information must
be conveyed through personal contact. Thus, the
student is urged to seek information from faculty
members, graduate students and industry. There
are, however, many aspects of apparatus design


SUMMER 1973























Harry Silla obtained his BS degree from City Univer-
sity of New York and his MS and PhD ('70) degrees from
Stevens Institute of Technology. His research interests
include combustion and transport properties of flame
plasmas.
that appear frequently enough to warrant discus-
sing them in lectures; for example the design of
flow systems. In the design laboratory there is no
need to withhold information from the student,
that is, the instructor knows the answer to a par-
ticular problem but withholds the answer to see if
the student can arrive at the same answer. There
are enough real problems to be solved without
creating artificial ones.
After making their design calculations the
students are ready to select standard parts such
as heat exchangers, pumps, valves and instru-
ments to produce a working system. In some cases
special parts must be designed and fabricated.
This requires a knowledge of materials, equipment
and fabrication techniques. Since the students do
not have the necessary experience to fabricate
equipment, they discuss their designs with the
departmental machinist and graduate students
who are working on experimental theses. At this
point the reliability of their design is also con-
sidered. Will the apparatus withstand the temp-
eratures and pressures? Is thermal expansion
considered? Are corrosion-resistant materials se-
lected? Is the apparatus safe?
If the necessary equipment is not available
in the department's stockroom, students are given
equipment catalogs, and they are urged to contact
sales engineers to discuss their problems. This
aspect of the design forces the students to con-
sider not only equipment costs but also the im-
portance of time as a factor in construction of
equipment.
The students are held responsible for the ac-
curacy of their work. It is not possible to check


all the detailed calculations for the many projects
that are being carried out. The laboratory instruc-
tors and graduate-student advisors, however, be-
cause of their greater experience will be able to
tell if a number or design is reasonable and thus
will prevent the student from making any serious
errors. It goes without saying that when the
students construct and test their equipment their
oversights, errors in calculations and planning are
emphasized. When a student obtains 90% on an
examination, he walks away pleased, but in the
design laboratory this frequently is not enough.
To extricate himself from his miscalculations
forces him to be very inventive.

DESIGN PROJECTS
A total of twenty projects are currently under
way. These projects are listed in Table 1. Some
of these projects have been continued from the
previous year. For these latter projects, the stu-
dents begin by reading final reports of last year's
graduates, evaluating their recommendations, and
outlining a program. This feature of continuing
projects adds considerable flexibility to the course,
because all projects are eventually completed.
Many of our projects are directed toward ex-
panding our laboratory facilities. Examples of
this type of project is the design of a Karr sol-
vent extraction column and a batch reactor facil-
ity. These projects will improve our capabilities
to handle more complex problems in the future.
Other projects are to design equipment to col-
lect engineering or physical property data re-
quired for design: for example, measuring heat
transfer coefficients in falling film evaporator or
obtaining vapor-liquid equilibrium data. Admit-
tedly, designing apparatus for measuring physical
property data does not have much glamour, but
this can be just as challenging as designing a dis-
tillation column.
One of our more novel projects is the develop-
ment of a process to extract potential antibiotics
from sea sponges. The objective in this project is
to extract sufficient material for an organic
chemist to determine the structure of biologically
active compounds. These compounds will then be
synthesized by an organic chemist. A similar pro-
ject is to determine the sex attractant dispersed by
a female lobster. The interest in studying the lob-
ster is for aquaculture and commercial trapping.
The students in this group are designing a Karr*
*We are grateful to T. C. Lo of the Hoffman-LaRoche
Co. for his help in the design of the extractor.


CHEMICAL ENGINEERING EDUCATION









TABLE 1-DESIGN LABORATORY PROJECTS
Project and Faculty Advisors
Separations
Extraction of Antibiotics from Sponges, A. K. Bose, J.
Kryschuk, H. Silla
Extraction of Sex Attractant of Lobsters from Sea Water,
A. K. Bose, R. L. Spraggins,b H. Silla
Controlled Cycling Solvent Extraction, H. Silla
Countercurrent Distribution Solvent Extraction, H. Silla
Fluid Bed Drying, H. Silla
Filtration, H. Silla
Polymers
Design of a Stress Relaxometer, C. G. Gogos
Effects of Porosity on the Physical Properties of Poly-
mers, K. C. Valanis
Development of a Hydrophilic Gel for a Gel-Permeation
Chromatograph, J. A. Biesenberger, I. Duvdevani
Instrumentation
Design of a Gel-Permeation Chromatograph, J. A. Biesen-
berger, I. Duvdevani
Reaction Engineering
Internal Recirculation Catalytic Reactor, G. B. DeLancey,
H. Silla
Catalytic Plasma Jet Reactor, M. J. McIntosh
Fluid Bed Combustion for Waste Treatment, H. Silla
Biomedical Engineering
Diagnosis of Lung Damage by Measuring Weight Shifts
in the Upper Body, J. R. Kaime, H. Silla
Ultrasonic Generation of Monodispersed Submicron Par-
ticles for Lung Studies, M. Lippmann', H. Silla

Engineering Properties
Heat Transfer in a Fluid Bed, M. Sacksa, H. Silla
Flow in a Fluid Bed, M. Sacksa, H. Silla
Heat Transfer in a Falling Film Exaporator, H. Silla
Plate Efficiencies of a Sieve Plate Distillation Column,
H. Silla
Transport Phenomena in a Flame Plasma, H. Silla
a. Doctoral student
b. Post-Doctoral Research Associate
c. M.D., College of Medicine and Dentistry of New
Jersey at Newark
d. Ph.D., New York University Medical Center


extraction colum to remove the sex attractant
from sea water.
Each year there are a few students who are in-
terested in biomedical engineering or who intend
to go to medical school. To satisfy this group of
students we have established a working relation-
ship with a local hospital to generate medical
projects. Last year two students designed and
built an automatic blood sampler which is now
being used by the hospital.** There is a need for


Besides giving a student... in process design
a broader view, the design laboratory also gives
the student experience in project engineering
and the design of experimental systems
for research and development.


rapidly locating which lung is damaged because of
accidents or diseases. This is not as simple as it
may appear. The student involved in this project
is investigating the possibility of measuring the
shift in the center of gravity of the individual
during his breathing cycle. During inspiration
the heart shifts in the direction of the damaged
lung, thus causing a shift in the individual's cen-
ter of gravity.
The design of instrumentation is a rich source
of projects and an area where many principles of
chemical engineering can be applied on a minia-
ture scale. Gel-permeation chromatography is an
example of a project of this type. In this project
the students were assigned the problem of rede-
signing an existing chromatograph with the ob-
jective of making a more reliable compact instru-
ment.

CONCLUSIONS

The design laboratory has been enthusiastic-
ally accepted by the students, who have christened
the design laboratory, "The Super Lab." Even
students who have had no prior interest in design
or who have chosen other areas of specialization
have been challenged by the projects. The design
laboratory not only is a challenge to the student,
but to the instructor as well because of the variety
of projects that must be managed, and because
the projects are constantly changing.
The design laboratory is still in the process of
evolving, and many problems will have to be
solved before the laboratory reaches maturity,
nevertheless, the results to date have been grati-
fying. One can see a student arrive in the Fall in
"rough form" and then leave in the Spring as a
much improved engineer. We have reached the
point in the design laboratory where we feel that
many of the design projects are equivalent to
industrial experience. The design laboratory
should play an important role in the undergradu-
ate chemical engineering curriculum.


**We are grateful to Dr. W. Perl of the College of
Medicine and Dentistry of New Jersey at Newark for
his help in the design of the sampler.


SUMMER 1973










FLOW MODELING AND PARAMETER ESTIMATION

USING RADIOTRACERS


R. W. ROUSSEAU, R. P. GARDNER and
R. M. FIELDER
North Carolina State University
Raleigh, North Carolina 27607

A common method of formulating dynamic
models is to introduce a process upset (such as a
tracer injection) and to measure the subsequent
response. There are several important restrictions
on the use of this method: the upset must be
measurable without being dramatic enough to
cause system failure, the production of off-
specification product, or a threat to the safety of
people and/or equipment; in addition, the experi-
menter must have access to the process stream,
either through a control valve or tracer injection
site, and he must have the capability of monitor-
ing the process response. The latter requirement
can be fulfilled in many industrial systems only
if a radioactive isotope is used as a tracer.
In the experiment to be described, a radio-
tracer impulse is injected into a turbulent stream
flowing in a straight pipe, and the count rate at
two downstream points is measured as a function
of time. The results are used to determine dis-
persion model parameters (mean residence time
and effective axial dispersion coefficient) by the
method of moments. The estimated values of the
dispersion coefficient are then compared with
values predicted by a published dimensionless
correlation of Peclet number vs. Reynolds num-
ber.
The educational objectives of the experiment
are to expose the students to the concepts of
process modeling and experimental determination
of model parameters, to lay a basis for subsequent
presentation of material on process dynamics and
the design and scaleup of nonideal process vessels,
and to introduce the topics of tracer technology,
radiosotopes handling and radiation detection,
subjects not usually encountered in the under-
graduate chemical engineering curriculum.
The background material presented to the
class covers fully the problems associated with
radioactive materials, and discusses alternative
tracers such as dyes and electrolytes. It also


briefly reviews problems which have been success-
fully attacked using radioisotopes (many of which
are presented in the work by Gardner and Ely
(1967)), including the determination of flow
rates and flow channel volumes in process units,
blood vessels and rivers and streams, formulation
of models for industrial processes and biological
systems, measurements of diffusion coefficients
and kinetic rate constants, measurements of mix-
ing efficiencies in stirred tanks, determination of
the existence of channelling or bypassing and
stagnant regions in process units, and measure-
ments of currents and dispersion patterns in re-
ceiving waters. We believe that this list, as exten-
sive as it is, represents only a fraction of the
potential applications of radioisotopes to the solu-
tion of problems with which chemical engineers
are likely to be confronted, and that having once
been introduced to radioisotopes in their educa-
tion, engineers will be more likely to think of
them when dealing with such problems.

EXPERIMENTAL
A schematic of the experimental system is shown in
Figure 1. Water is fed to the system from a constant
head tank through a rotameter into a long % inch NPD
galvanized pipe, and from the pipe into a storage tank.


*Detectors


Rotameters


Sewer


Fig. 1. Schematic of Experiment.


Tracer is injected into the pipe through a regular pipe tee
fitted with a rubber septum. Detectors are mounted at
either end of a 20 foot straight section of the pipe down-
stream of the tracer injection point. The storage tank
is used to allow the radioactivity to decay to a negligible
level before the effluent is sewered.


CHEMICAL ENGINEERING EDUCATION




























Ronald W. Rousseau received his BS, MS, and PhD from
Louisiana State University. He has industrial experience
with the Ethyl Corporation and Westvaco, Inc. He has
been at North Carolina State University since 1969; re-
search interests include crystallization, vapor-liquid
equilibria, process modeling and applied polymer chem-
istry. He teaches mass and energy balance calculations,
transport processes and mass transfer operations.
Robin P. Gardner received his BChE and MS from North
Carolina State University and his PhD from Pennsylvania
State University. From 1961-63 he was Scientist in Charge
of Short Courses on Radioisotope Applications in Indus-
try at the Oak Ridge Institute of Nuclear Studies and
later was Assistant Director of the Measurement and
Controls Lab at the Research Triangle Institute. He was
an IAEA Expert at the Institute of Radioactive Research
in Belo Horizonte, Brazil and currently is Professor of
Nuclear and Chemical Engineering at NCSU. (center)
Richard M. Felder did his undergraduate work at the
City College of New York and obtained his PhD from
Princeton. He spent a year at AERE Harwell, England
on a NATO Postdoctoral Fellowship, two years at Brook-
haven National Laboratory, and came to NCSU in 1969.
Recently he has become involved with photochemical re-
actor analysis, radioisotope applications, and applica-
tions of engineering technology to medical and environ-
mental problems. He has served as a consultant to the
government of Brazil on industrial application of radio-
isotopes. (right)

Manganese-56, in the form of an aqueous Mn(NO3)2,
solution, was selected as the tracer because it is a gamma
ray emitter and hence can be detected through metal
walls, and because it has a half-life of only 2.6 hours,
which causes it to decay to negligible levels in less than
24 hours. Geiger-Mueller tubes were the detectors; their
outputs were fed to a Nuclear Chicago rate meter coupled
to a Leeds and Northrup strip chart recorder.
Both single and two-point detection methods were
demonstrated in the experiments, using detectors placed
at distances of 6 and 26 feet from the point of injection.
While it is desirable that the detectors have approxi-
mately the same sensitivity, deviations from this condi-
tion are not serious because of the method of data


analysis. Typical output from a run using both detectors
is shown in Figure 2, which plots the counting rates re-
corded by the first and second detector vs. the time from
injection.




70 -



60 -



-50 -
0


S40 -



S3 -
F-


20 -



10 -



35 30 25 20 15 10 5 0

TIME sec

Fig. 2. Typical Analog Output.

COMPUTATIONAL PROCEDURES

Flow systems in which a measurable but finite
amount of axial mixing occurs are commonly
simulated by two-parameter models, such as axial
dispersion and tanks-in-series models. The para-
meters of these models are simply related to mo-
ments of the system impulse response function,


SUMMER 1973










and may be conveniently estimated from numeri-
cally calculated moments of experimental re-
sponse curves. In contrast, parameter estimation
techniques such as time-domain and frequency-
domain regression require considerable computa-
tional effort, and are consequently less suitable
for inclusion in a junior-level laboratory course.
The quantities needed to estimate the para-
meters of a two-parameter flow model by the
method of moments are


St Ri(t)dt

Ri (t)dt
2o


i = 1,2


(1)


2 (t-pi) 2Ri(t)dt
o. 1 = 1,2 (2)
S Ri(t)dt
where Ri(t) is Lhe counting rate at the ith detec-
tion station, and ui and -i2 are respectively the
mean and variance of this function. The pro-
cedure is to choose a model, derive expressions
for the model parameters in terms of ui and
a-i2, evaluate the latter quantities from the experi-
mental impulse responses and Eqs. (1) and(2)
by numerical quadrature, and use the resulting
values to solve for the model parameters. In the
experiments run so far, hand calculations of the
moments from analog output were required; in
the future, the output from the rate meter will
be punched on paper tape, which will in turn be
used as input to a Simpson's Rule quadrature
subroutine.
The model chosen for illustrative purposes
was the doubly-infinite axial dispersion model.
The assumptions inherent in this model and so-
lutions for the impulse response and its moments
are outlined by Himmelblau and Bischoff (1968)
and Levenspiel (1972). The relations used in the
single-detector measurements are as follows:


- L
S1 = i


i = 1,2


(3)


2
2-+ and Pi = vLi/D (4,5)
i1 Pi
where Li is the distance from the injection point
to the ith detector, v is the mean flow velocity in
the tube, and D is the effective axial dispersion
coefficient. The procedure followed was to calcu-
late ul and o-2 from the experimental Ri data us-
ing Eqs. (1) and (2), then to evaluate the ve-
locity v from Eq. (3), the Peclet number P1 from
Eq. (4), and finally D from Eq. (5). The two-
detector method provides two advantages over


the single detector method: the injection does not
have to be a perfect impulse, and errors in syn-
chronizing the time of injection with the record-
er output are eliminated. The equations for the
two detector method are
L2-L1
21 (6)

2 2
2 -1 2 (7)


v(L2-L1) (8)
D
In this case the velocity v is calculated from the
numerical moments using Eq. (6), the Peclet
number P is calculated from Eq. (7), and D is
calculated from Eq.(8).
Table 1 shows values of flow velocities deter-
mined with a rotameter and calculated as out-
lined above. It is interesting to compare the re-

Table 1-Flow Velocities


Run u(from rotameter) u,


2.01ft/sec
1.53
1.0
1.0


1.77
1.07
0.938


u, u,,
1.88 1.91
1.37 1.4l
0.945 0.9
1.03 -


sults obtained by the one- and two-point tech-
niques: the average error is 16% for the single
detector at 6 feet, 6% for the single detector at
26 feet, and 2% for the two detectors. Figure 3
in a plot of the effective axial dispersion coeffi-
cient vs. the Reynolds number, and shows that
the data fall within the range predicted by a


L
N



L_
u
o
C

(C
Z
o


r-
*


Si
0
Li
a
0i


M ----_I 111111 I I 11111 t'-
80 -
70-
60 -
50 -
>40 -
,30 -

20


10-
9-
al
6-
5 -
4-
3
2 Accepted Experimental Range


) I I IIII I 11 11 I I 1111 l


I 2 3 4 5 6 78910 20 30 40 50bU6fUU90
REYNOLDS NUMBER x IF3
Fig. 3. Dispersion Coefficient as a Function of Reynolds Number.


CHEMICAL ENGINEERING EDUCATION


.^


method of moments are









The educational objectives of the
experiment are to expose the student
to the concepts of process modeling
and experimental determination of
model parameters ...


correlation reprinted by Himmelblau and Bischoff
(1968). Since doing so would not serve any par-
ticular purpose in light of the educational objec-
tives of the experiment, we have not attempted
to confirm the negligibility of adsorption other
than to note the absence of long tails on the im-
pulse response curves.

DISCUSSION
The students are given two 3-hour laboratory
periods to complete the experiment. In the first
period they go through the entire experiment
without actually using the radiotracer. Under this
format they each get a chance to become familiar
with the equipment and injection procedure with-
out the worry of spills or other hazards. Also
during the first 3-hour session they are instructed
in fundamentals of radiation detection, particu-
larly as related to Geiger-Mueller characteristics,
and in radiation safety. In the second 3-hour
period the actual runs are made, but the injec-
tions and tracer handling are not done by the
students, who merely observe. The runs them-
selves are not particularly time-consuming, so
that each student has sufficient time to carry out
the necessary calculations and to seek individual
instruction on any aspect of the experiment.
The participating students appeared to get a
great deal out of the experiment; the only strong
objection was to the necessity of calculating mo-
ments graphically from analog output, a require-
ment which will be eliminated in the future when
digital output equipment becomes available. A
potential problem with an experiment of this sort
being given on a junior level is that the students
may have to accept on faith the utility of much
of what they are doing. This did not appear to
be a matter of concern to the students, however,
possibly due in part to the fact that they had
been introduced to elementary concepts of model-
ing (and in particular to the dynamic response
of a first-order process) in a previous course. The
experiment also served to make related material
subsequently encountered in senior courses on
reactor design and process dynamics and control
a great deal more meaningful to those who par-
ticipated in it.


Once the basic procedure for a stimulus-
response experiment of this type has been estab-
lished, it is a relatively easy matter to study a
variety of flow systems using the same technique.
We are currently making provisions for the fol-
lowing experiments:
1. Flow and dispersion in packed columns.
2. Flow in obstructed tubes
3. Detection of stagnancy and channeling
4. Residence time distribution of stirred tanks in series
5. Variation of RTD with stirring rate in a single stirred
tank-determination of mixing efficiency.
6. Impulse responses of laminar flow systems.
Our present plan is to include one of these ex-
periments (probably the one on the packed col-
umn) in the laboratory course, either in addition
to or instead of the empty tube experiment, and
to use the others as senior projects.D

REFERENCES
Gardner, R. P. and R. L. Ely, Jr., "Radioisotope Measure-
ment and Applications in Engineering," Reinhold Pub-
lishing Co., 1967.
Himmelblau, D. M. and K. B. Bischoff, "Process Analysis
and Simulation," Chapter 4, John Wiley and Sons, Inc.,
1968.
Levenspiel, 0., "Chemical Reaction Engineering," Chapter
9, John Wiley and Sons, Inc., 1972.


LAB WORKSHOP (Continued from p. 125)

D. J. Graves discussed the use of audio-visual
packages in the preparation phase of the labora-
tory experiment. The student prepared modules
used to describe complex pieces of equipment,
measurements points, flow paths, and complex
procedures. At the University of Pennsylvania
the audio-visual modules have reduced laboratory
time and allowed students to continue to work on
project experiments after previous groups have
graduated. Two sample audio-visual modules were
shown to illustrate their use with typical experi-
ments.
The entire proceedings of the laboratory work-
shop are to be published and can be obtained by
sending a check for $10.00 payable to The Uni-
versity of Michigan to Professor H. Scott Fogler,
Department of Chemical Engineering, The Uni-
versity of Michigan, Ann Arbor, Michigan 48104.
The price of the bound proceedings, which will be
available after May 1, 1973, was established by
the ASEE ChE Division in order to minimize any
loss of funds from printing costs.


SUMMER 1973










A COMPUTERIZED UNDERGRADUATE PROCESS

DYNAMICS AND CONTROL LABORATORY

R. A. SCHMITZ
University of Illinois
Urbana, IL 61801


A project to computerize the undergraduate
process dynamics and control laboratory in the
Department of Chemical Engineering at the Uni-
versity of Illinois was begun in 1969. The plan
was to use an existing IBM 1800 computer, which
was operating on a time-sharing basis in the
School of Chemical Sciences, to provide a facility
for computer-aided instruction and for computer-
aided experiments by undergraduate students.
Our motivation for the project was the realization
that a facility of this type would permit more ex-
tensive and more meaningful laboratory studies
of process dynamics, simulation and control than
are possible in conventionally-equipped labora-
tories. We also felt that the hands-on use of an
on-line data acquisition and control system would
be a valuable experience for the students and that
the lecture portion of certain courses would be
greatly improved by the demonstrations and vis-
ual displays made possible by an on-line com-
puter. Similar projects have been undertaken at
a few other chemical engineering departments at
universities in the United States and Canada1'7.
A recent report of the CACHE (Computer Aids
in Chemical Engineering Education) Committees
presents a brief description of these activities.
Certainly at this point in time, the use of a
computerized undergraduate laboratory in ChE
education is a relatively new development. Since
the few facilities that are in existence were estab-
lished quite dependently, each incorporates some
unique features, and publications of their descrip-
tions should be informative and valuable to other
departments which may embark on similar proj-
ects. Many such departments will probably find
themselves in a situation similar to ours at Illinois
at the outset of this project; that is, with an
accessible time-sharing computer of the large or
medium-sized variety and an existing laboratory
equipped with conventional instruments and con-
trollers. While the task of interfacing the labora-
tory and the computer and of developing a soft-
ware system in such cases may be demanding in


Roger A. Schmitz received his BS degree from the
University of Illinois and his PhD from the University
of Minnesota. He joined the ChE faculty at the University
of Illnnois in 1962. His area of specialization is the stabil-
ity and control of chemically reacting systems. He was
awarded a Guggenheim Fellowship in 1968-69 and was the
recipient of the Allan P. Colburn award of the AIChE in
1970.

terms of labor, the investment of dollars in hard-
ware should be minimal. Departments not so for-
tunately situated with regard to an existing com-
puting facility will probably go the route of in-
vesting in a minicomputer.

THE SYSTEM AND ITS OPERATION
The IBM 1800 computer in the School of Chemical
Sciences has 32,000 words of core memory and uses three
disks (500,000 words each) for auxiliary storage. It is
equipped with the usual peripherals including (1) an
analog-to-digital (A/D) converter capable of receiving
signals on a -5 to +5 volt range, (2) a digital-to-analog
(D/A) converter capable of sending voltages on the
range 0 to +5 volts, and (3) a card reader. A description
of the computer system, the monitoring program and
IBM's Time-Sharing Executive (TSX) System has been
published.9
Three thirty-conductor cables connect the computer to
the process control laboratory. These cables actually
branch to nine stations connected in parallel. Four of
these are chemical engineering research laboratories,
another is a terminal in a room housing an EAI 580
analog computer, and the remaining four are in the
process control laboratory. One cable is devoted entirely
to an IBM 1053 output printer which can be connected
at any of the stations.
A user at any station in the process control labora-
tory has access to A/D and D/A channels, a process in-
terrupt switch, digital inputs (two-position switches) and


CHEMICAL ENGINEERING EDUCATION
















PROCESS

( i1( level


Transducers -5 to +5v
Amplifiers t
Drivers

IBM 1053 Printer


Disk-Stored Programs


(2) heat exch Transducers to+5v
(3) pH inCSTR to 5 psiIII- 5v
tog. 1. Schematpsic Diagram of Closed-Loop Systems




Fig. 1. Schematic Diagram of Closed-Loop Systems


digital outputs (lights). Altogether there are eight A/D
and four D/A channels, nine lights, and nine switches.
The switches and lights allow for user inputs to the
stored programs and for user options.
To gain access to the disk-stored programs for the
process control laboratory, the user at any station must
activate the process interrupt switch. This causes the
transfer into core and the execution of an initializing
program which governs the building of the core load
for the process control laboratory. The core load consists
of a supervisory program along with associated sub-
programs and the subroutines used-all initially stored
in disk memory. When core-load building is complete,
execution of the supervisory program begins. It first in-
structs the computer to flash two lights at all stations
in the laboratory repeatedly, waiting for the user to
select, by means of switch settings, a desired subprogram.
As it is presently written, the supervisory program can
accommodate twenty-seven different subprograms each
having a different three-digit code number. To call a
desired subprogram, the user enters the three integers in
the appropriate code number successively in binary form
using the two switches at his experiment station. After
a three-digit code is entered, the supervisory program
branches to the subprogram stored under that code. Upon
completion of the subprogram, control is returned to the
supervisor, lights are again flashed at all stations wait-
ing for another subprogram to be called.
In the usual operation of the laboratory, the initializa-
tion procedures are handled by the instructor or the
laboratory assistant. The student then encounters the sys-
tem and takes over its operation with the supervisory
program being executed; that is, with lights flashing in
wait of a subprogram code to be entered. The students
are responsible for the writing, disk-storing, and de-
bugging of the subprograms. They ordinarily work in
three-man groups, and each group is assigned a sub-
program code number for the course. The subject of
programming will be taken up in more detail in a later
section of this peper.
Only one subprogram can be executed at a time as
the system presently stands. This means that no two
experiments in the control laboratory, both using the
computer, can be carried out simultaneously. We can
make programming modifications to remove this limita-
tion if it becomes necessary to do so.


As mentioned earlier, the computer operates on a
time-sharing basis. For background jobs, that is those
not involving real-time applications, each user's core load
resides in the core and is executed for a short time
before being "swapped" to disk-storage for a period of
time. Our system monitor program presently allots a time
slice of twenty seconds for core residence time. Much of
the computer usage in the process control laboratory
falls into this background category. Those programs,
however, which make use of the real-time clock; that is,
those which call for frequent interrupts for reading and/or
sending analog signals at specified intervals of times, have
priority status and are not swapped from the core. The
computer services these frequent interrupts as a fore-
ground task, returning to background jobs in the interim
periods.

THE LABORATORY
The equipment at each of three of the four
stations in the process control laboratory com-
prises a simple control loop with a single meas-
ured variable and one manipulated variable. One
of these involves the control of the liquid level in
a cylindrical column packed with Plexiglass
spheres; another, the control of temperature of
the effluent water from a tube-and-shell heat ex-
changer; and the third, the control of pH in a
stirred vessel. Each of the three setups, which are
represented schematically in Figure 1, involves
standard measuring and signal transducing de-
vices so as to produce dc voltage signals for the
measured variables on the range -5 to +5 volts
for input to the A/D converter on the computer.
The measurement originates from a process pres-
sure (hydrostatic head) -to-current transducer in
the liquid level system, from a thermocouple in
the heat exchanger and from a submerged pH
electrode assembly in the stirred vessel. The D/A
signal from the computer is converted to a cur-
rent and then to an air pressure signal in the


Fig. 2. Photogaph of Liquid Level Control System.


SUMMER 1973


)/A









range 3 to 15 psi. The pneumatic signal is sent to
a diaphragm control valve, the final control ele-
ment in all three cases. The manipulated variables
are (1) the flow rate of water to the packed
column of the liquid level system, (2) the steam
pressure on the tube side of the heat exchanger
and (3) the flow rate of a hydrochloric acid solu-
tion to the stirred vessel.
The photograph in Figure 2 shows the physi-
cal layout of the liquid level system; the others
are similar. As shown in the photograph, each
station is equipped with a control panel on which
the process signal flow is printed. A close-up view
of the control panel for the liquid level process is
shown in Figure 3. The panel conceals most of the


Fig. 3. Operator's Control Panel for Liquid Level Experiment.
wiring connections and interfacing equipment.
As can be seen in the photograph of Figure 3, the
panel contains a process interrupt switch, two
lights (digital outputs) and two switches (digital
inputs). As is also shown in the photographs,
each of the three systems is equipped with a con-
ventional three-mode analog controller which can
be switched into or out of the loop as desired.
The equipment and the wiring connections for
these systems are intended to be permanent. In
working with these processes, therefore, the stu-
dent in the laboratory does not assemble appara-
tus or make any interface connections.
Typical experiments with the three systems
may involve the formulation and testing of
mathematical models via step response, frequency
response and analog simulation methods, and in-
vestigations of the closed-loop behavior both with
direct digital control and with conventional con-
trol. In all experiments the subprograms called
by the experimenter may contain instructions to
read and store data, send feedback signals, dis-


play experimental results on an oscilloscope,
carry out calculations and print results or data
on the output printer. Further description of the
programming effort required will be given in the
next section.
A fourth apparatus, which makes use of the
computer facility, consists of two different types
of pneumatic control valves and associated signal
converting and conditioning hardware. Experi-
ments with this setup, depicted schematically in
Figure 4, can be carried out using the control
panel at the pH control apparatus. As shown on
the left portion of Figure 4, voltage signals from
the computer may be sent to the valves, separ-
ately or simultaneously, and voltage signals, orig-
inating from displacement transducers attached
to the valve stems, may be sent to the A/D con-
verter on the computer. In the simplest experi-
ments with this system, the objective would be to
study and compare the frequency response of the
two valves. In such instances the subprogram
called by the student would instruct the computer
to send a sinusoidal signal of a specified ampli-
tude and frequency to the valves and to read a
voltage signal which indicates the instantaneous
valve positions. If he so desires, the student may
easily have his subprogram analyze the data and
print information to be used in constructing a
Bode diagram. He may also have results dis-
played on an oscilloscope.
With an analog computer inserted in the sys-
tem, as shown in Figure 4, real-time simulations
involving the simulation of some process on the
analog computer and incorporating real valve
dynamics are feasible. In experiments of this
type, the student may study the effects of non-
ideal valve dynamics in various control loops by
experimenting with simulated feedback systems


Fig. 4. System for Valve Dynamics Experiments and Real-Time
Simulations.

CHEMICAL ENGINEERING EDUCATION










containing ideally simulated valves in one instance
and the real valves in another. It will also be
possible in advanced studies to interconnect the
analog computer, digital computer and any or all
of the laboratory stations to form a complex
multivariable system containing some simulated
components and some real ones. A TR-10 analog
computer is available in the laboratory for some
small scale experiments, and an EAI 580 is
housed at a separate station for more extensive
simulations. For either computer, the linkage
from the patch panel on the analog machine to
the cables from the IBM 1800 is made through
a portable interface panel. The panel provides
access to all D/A and A/D channels to the IBM
1800 and to all nine lights and switches. The
photograph in Figure 5 shows an interconnected
system comprising the TR-10 analog computer,
the IBM 1800, the interface panel and a pneuma-
tic control valve. This system was set up to
demonstrate a real-time simulation of a chemical
reactor under direct digital control.
The fourth station in the process control
laboratory consists simply of a laboratory bench
at which the portable interface panel can be con-
nected to the cables from the computer. The pur-
pose of this station is to provide a versatile gen-
eral-purpose facility at which a variety of bench-
top experiments or demonstrations can be set up
and carried out in a short time, some perhaps on
a one-shot basis. Usually these experiments will
involve studies of the dynamics of individual
components or devices. A simple example is a
study of the dynamics of thermocouples with


Fig. 5. Photograph Showing a System Consisting of a Pneumatic
Control Valve, a Portable Interface Panel to the IBM 1800 Computer
and a TR-10 Analog Computer being used in a Real-Time Simulation
by an Undergraduate Student.


TABLE I. SUBROUTINE DESCRIPTIONS

Subroutine Function
ANDIG Read and print the instantaneous voltage on A/D channels)
specified in arguments in the calling statement.
ANLOG Periodically read A/D channels, send voltages on D/A
channelss, (see options below) and store data.
The sampling period and channel numbers are specified
in arguments in the calling statement.
Options:
(a) data logging, no D/A signals
(b) data logging with proportional D/A signal
for feedback control
(c) data logging with function generation (D/A
voltage) for analog simulations
(d) combination of (b) and (c).
DIGAN Send and hold a voltage on D/A channelss. The
magnitude of the voltage(s) d te chan nel numbers)
are specified arguments.
DISPY Send voltage data stored in INSKEL common arrays
(e.g. stored during real-time operations) for oscilloscope
display (i.e. cycle through the arrays). The arrsa to
be displayed and the variables for the x and y axis are
specified arguments.
FLASH Flash lights and wait for switches (digital inputs) or
process interrupt to be set before proceeding. Light
numbers) and flashing frequency are specified arguments.
PEROD Send sinusoidal voltage on a D/A channel ant log data
from A/D channelss. The frequency and period of the
sine function and the channel numbers are specified
parameters. An option in the subroutine permits the
user to specify some other periodic function (tabulated)
in place of the sine function.
PRIT Print voltage data stored in INSKEL common arrays
(e.g. stored during real-time operations). The arrays
to be tabulated are specified in arguments in the calling
statement.


various types of shielding, the computer being
used to read, store, print and display the thermo-
couple signals versus time.
As previously indicated, an oscilloscope with
an attached Polaroid camera, is available in the
laboratory. Thus, by employing a display subrou-
tine, as described in the following section, a stu-
dent can immediately observe his experimental
data and obtain a photograph for insertion in his
laboratory report.

PROGRAMMING
In order to keep student programming re-
quirements and de-bugging difficulties at a man-
ageable level, we have written a number of basic
programs for the process control laboratory and
have stored them permanently on one of the disks.
In addition to the initializing and supervisory
programs which are transferred into core
memory during initialization procedures, these
include a number of subroutines whose functions
include reading voltages, sending feedback sig-
nals, storing, displaying and printing data and
governing lights and switches. A list of these
routines along with a very brief description of
each is given in Table I. A complete description
of these routines is not essential here, but per-
haps a few comments, in addition to those given
in Table I, on some of them are called for. Each
subroutine is accessible through a standard Fort-
ran call statement that includes a list of argu-


SUMMER 1973








ments. Three of the routines, namely ANLOG,
DISPY and PEROD, handle real-time operations.
Those routines subsequently branch to various
entry points in an assembly language program,
also written by us specifically for the process con-
trol laboratory, which resides permanently in the
core memory initialization. Thus by means of
Fortran calls to these three subroutines, the user
has access to a variety of real-time operations.
The initiation and termination of the real-time
operations of data logging and sending by the
computer in ANLOG and PEROD are handled by
the student at the experiment site by means of
switch settings. For example, when subroutine
ANLOG is entered, a light is flashed (the light
number is specified in the list of arguments).
Periodic voltage readings and sending begin
when the corresponding switch is turned on. The
reading and sending end and the execution of the
next statement in the student's subprogram takes
place when that switch is turned off. In the
meanwhile, the user can call for the storing of
data over intervals of time during which a second
switch (the number of which is also specified in
the argument list) is turned on. The usage of
subroutine PEROD is very similar.
It should be noted that the subroutines in
their present form do not permit the changing of
parameters during the course of real-time opera-
tions. Thus the values of the proportional band,
sampling interval, etc., are specified prior to the
call or in the calling statement of ANLOG and
cannot be changed during the execution of that
subroutine In order to study various values of
these parameters, the student would either have
to call his subprogram repeatedly or have in-
serted his call statement within a loop for repeti-
tive calls.
As mentioned earlier, the student is required
to write the Fortran subprogram to which the
supervisory program branches when a certain
combination of switch settings is entered. Be-
cause of the available subroutines, this pro-
gramming requirement is simple. For example,
the following sequence of statements constitutes
the set of necessary instructions for executing
direct digital control with data logging, followed
by an oscilloscope display and printing of stored
data:
CALL ANLOG (parameters)
CALL DISPY (parameters)
CALL PRINT (parameters).


A study of frequency response would require
the substitution of "CALL PEROD (para-
meters)" in place of the call to ANLOG. Of
course, the student may make his program quite
involved to the extent of providing various ex-
perimental options and of carrying out calcula-
tions with the experimental data if he so desires.
Though the minimal programming require-
ment is quite simple, nearly trivial for some ex-
ercises, we feel that it is an important part of the
student's usage of the system. It gives him a
greater overall appreciation and understanding
of his experimental goals, of our particular sys-
tem and of software aspects associated with on-
line computing in general. Having to write a com-
puter program for his experiment in advance of
the laboratory session forces the student to study
the experiment carefully and to plan his labora-
tory procedure step-by-step. This in itself is a
noteworthy benefit of a computerized laboratory
in which the students are required to program the
experiments.
In the operation of the laboratory, the labora-
tory assistant or instructor assists the students
in disk-storing and de-bugging their subprograms
on the afternoon preceding the scheduled labora-
tory session. Some additional de-bugging is often
required during laboratory meetings. As men-
tioned earlier, the students work in three-man
teams, and therefore programming is a group
effort. Our curriculum contains a required course
in digital computer programming in the fresh-
man or sophomore year. In addition, the students
will have used Fortran programming in carrying
out assignments in a few courses prior to their
enrollment in the process control course.
In our initial or "trial" usage of the sys-
tem (Fall semester, 1972) the students carried
out three computer-aided experiments. We were
able to give adequate programming instruction
in two 90-minute workshop sessions early in
the semester. The sessions included a general
discussion of on-line computing and computing
control in addition to specific instructions and
:exercises on the usage of our system. Each
student was given a laboratory manual which
described the computerized laboratory and con-
tained instructions on the usage of disk-stored
subroutines and on the preparation of the
required subprograms. It also contained sev-
eral example subprograms. The workshop ses-
sions were followed by laboratory demonstra-
tions. We found that the preparatory instruc-


CHEMICAL ENGINEERING EDUCATION









tions so given were quite adequate. The students
were able to proceed from that stage at the level
of independence which we had sought. With some
minor revisions in the manual and subroutine
functions, we plan to introduce several additional
computer-aided experiments for the Fall term,
1973.
CONCLUSION
In this paper we have described briefly our
system for computer-aided experiments in an
undergraduate process dynamics and control lab-
oratory at the University of Illinois. We have
included some description of its usage, but will
elaborate further on the course description and
on the specific laboratory experiments and dem-
onstrations in future publications.
In designing the apparatus and the computer
programs for the system, we placed much value
on retaining basic simplicity so that students, in
an introductory course, would be able to under-
stand the operations of an on-line computing
facility and be able to use it to advantage on a
hands-on basis. We also strived for versatility
so that new experiments could be incorporated
easily and that utilization of the system could be
extended to more advanced topics, to very com-
plex networks and even perhaps to courses on
other subjects, such as applied kinetics.
We also felt that it was important to leave
the programming of experiments to the student,
but we have made available a number of subrou-
tines which make this task relatively simple.
There is a strong temptation for instructors in
such laboratories to program the experiments
completely and reduce the role of the student to
that of executing the programs. While such ex-
periments may be elegantly programmed and
virtually fail-safe, they may also stifle most of
the student's thought input. With the student in-
volvement in programming, even at a very simple
level, a greater appreciation of process-computer
interfacing is imparted, a greater degree of open-
endedness is automatically provided and presum-
ably more thought input, creativity, originality
and interest on the part of the student will be
realized.
Our facility was employed for the first time
in an introductory undergraduate course on pro-
cess dynamics and control in the Fall semester,
1972. Three computer-aided experiments con-
ducted by the students and two demonstrations
carried out by the author of this paper, were


used, and the consensus of opinions of students,
assistants and instructor was that the endeavor
was highly successful. The student interest and
enthusiasm for the laboratory were noticeably
greater than they had been in previous years
when similar experiments were conducted with-
out the aid of the computer. We plan to introduce
several additional experiments and demonstra-
tions for the next offering of the course (Fall,
1973). It will be possible to discuss more defini-
tive results and to present realistic evaluations
after a few more semesters of experience. Hope-
fully, the system we have developed as well as our
experiences in implementation will be helpful to
others embarking on similar projects.

ACKNOWLEDGEMENTS
This project received most of its financial support
through a grant from the National Science Foundation.
Departmental help was provided mainly in the form of
graduate teaching assistants and laboratory instructors.
Most of the electronic interfacing hardware was designed
and built in the electronics shop in the School of Chemi-
cal Sciences. The staff of the School's computer lab pro-
vided help with much of the basic programming. The
author would like to acknowledge particularly the val-
uable assistance of Mrs. Pat Anderson with programming
and the work of Dr. Ming Fang who designed and in-
stalled much of the hardware and apparatus.

BIBLIOGRAPHY
1. Christensen, J. H. and P. M. Vargo, "Education in
Real-Time Computing", Chem Engr. Ed. 5, 30
(1971).
2. Fisher, D. G., "Real-Time Computing in the Uni-
versity", Chem. Engr. Ed., 5, 24 (1971).
3. Westerberg, A. W. and R. C. Eschenbacher, "A
Real-Time Computer Control Facility", Chem. Engr.
Ed., 5, 32 (1971).
4. Wright, J. D., "Education in Computer Control: How
to Make Your Real-Time Clock Tick', Pulp and
Paper Magazine of Canada, 72, 4, 29 (1971).
5. Idier, M. and D. A. Mellichamp, "Computer Moni-
toring and Control of a Process Dynamics Labora-
tory', Paper No. 4b, 71st National Meeting of
AIChE, Dallas, Feb., 1972.
6. Wissler, E. H., "Computer Aided Methods for
Chemical Engineering Laboratories", Paper No. 4a,
71st National Meeting of AIChE, Dallas, Feb., 1972.
7. Moore, C. F., "A General Purpose Data Acquisition
and Control Utility," 7th Annual Conf. on Use
Digital Computers in Process Control, Louisiana
State University, Feb., 1972.
8. Elzy, E., L. B. Evans, R. C. Weaver and A. W.
Westerberg, "Real-Time Digital Computer Systems
in Undergraduate Education, Paper No. 47c, 72nd
National Meeting of AIChE, St. Louis, May, 1972.
9. Secrest, Don, "Time-Sharing Experimental Control
on a Small Computer", I&EC 60, 6, 74, 1968.


SUMMER 1973










international


A NEW TRADITIONAL UNIT OPERATIONS

LABORATORY COURSE


AAGE FREDENSLUND
Instituttet for Kemiteknik
Danmarks Tekiniske Hojskole
2800 Lyngby, Denmark


In 1968 the Department of Chemical Tech-
nology, the Technical University of Denmark,
moved from an old location in central Copenhagen
to a modern, spacious campus north of town.
The department was given adequate funds to de-
velop new laboratory courses, and a new, tradi-
tional unit operations laboratory course is now
completed. It is the purpose of this communica-
tion to describe the course in some detail so that
other chemical engineering departments may
benefit from this experience. The author will
gladly furnish further information regarding de-
tails of the course upon request. Before proceed-
ing further, it is necessary to explain the purpose
of the course.

PURPOSE OF THE COURSE
It is characteristic for the Danish chemical
industry that it consists of many rather small
units. One can therefore not depend on the indus-
try to give chemical engineering graduates a
professional, rounded technical training program.
This, and the fact that the ChE students are sub-
jected to a thorough physics laboratory course
early in the curriculum, indicate that in design-
ing the unit operations laboratory course, one
should emphasize real process equipment rather
than physical phenomena. That is to say that the
course should be based on equipment resembling
process equipment rather than transport phe-
nomena experiments.1
In the foreword of the laboratory manual2
for the course the purpose is stated as follows:

*To give an understanding of and a physical feeling
for the processes and transport phenomena taking
place in large scale chemical processing equipment.


*To show how the principles developed during the
lectures in unit operations may be used in designing
and running processing equipment.
*To furnish insight into how the unit operations used
in the chemical industry work and the limitations of
these.

These purposes have had a large influence on
the design of the equipment for the experiments.
One might say that the course constitutes a
"movement" away from transport phenomena
laboratory type equipment. This does not mean,
however, that transport phenomena type measure-
ments (for example, single film heat transfer
coefficients as opposed to overall coefficients) are
not carried out in the course. Indeed they are,
but the tendency is to perform the measurements
in process equipment so that the students do not
have to extrapolate from model experiments to
real life. It is understood that a similar "move-
ment" is taking place in several ChE departments
in the US.

COURSE CHARACTERISTICS
The course is offered twice a year in three-
week periods during which the students devote
their full attention to the course. The maximum
number of students is 70 per three-week period.
Since this is an introductory course, it was found
best to expose the students to as many different
unit operations as possible. For pedagogic
reasons it was decided to work with small teams
of students (two per team). For these reasons, a
relatively large number of experimental units
was found necessary. It was also found necessary
for the students to work with ready-made experi-
mental units. If the students were to construct
the equipment themselves, many of the course


CHEMICAL ENGINEERING EDUCATION
























Aage Fredenslund received BS, MS, and PhD ('68)
degrees from the University of Wisconsin. He has taught
unit operations, transport phenomena, and ChE thermo-
dynamics at Instituttet for Kemiteknik since 1968. His
research interests include high pressure vapor-liquid
equilibria, PVT properties of mixtures, and multicom-
ponent separations.

objectives could not be achieved. Later on in the
curriculum, the students have a chance of con-
structing their own equipment during (required)
senior thesis work.
Altogether 27 experiments have been designed
and constructed, and these experiments are di-
vided into nine groups, each containing three
similar (but not identical) experiments. The
students must not have more than one experiment
from each group. The experimental units are de-
scribed briefly below.
Before each experiment is to be performed,
the students are briefed as to the operating con-
ditions and the report requirements. A variety of
possibilities, is built into most experiments. It is
found that the students can carry out the experi-
ments with the aid of the laboratory manual2
without much further supervision and that they
find the experiments quite challenging. The cor-
rected reports are, of course, discussed with the
students, who at the end of the course receive a
"pass" or "fail" on the basis of the reports.
The laboratory course is housed in two ad-
jacent localities: an apparatus hall of ceiling
height 7 m, containing a small area with ceiling
height 16 m, for pilot scale experiments and an
ordinary laboratory for bench scale experiments.
Both locations are provided with ample steam,
water, gas, and electrical supply.

EXPERIMENTS
A short abstract is given for each experiment
below. A capital letter in the experiment number


(e.g. 1A) indicates that the experimental unit is
placed in the apparatus hall, and a small letter
(e.g. ib) indicates that the experimental unit is
located in the ordinary laboratory.
1. FLUID FLOW. Flow of water in pipes. Flow of
water in tubing. Flow of air in ducts.
2. FLOW OF FLUIDS THROUGH POROUS MEDIA.
Filtration. Fluidization. Flow through packed columns.
3. EVAPORATION AND CONDENSATION. Evapora-
tion in a vertical tube. Evaporation in a vertical tube.
Condensation.
4. HEAT EXCHANGE. Heat transfer in pipes. Heat
transfer in pipes. Unsteady state heating of water.
5. DISTILLATION. Distillation in a bubble cap
column. Simple and batch distillation. Continuous distil-
lation.
6. ABSORPTION. Absorption in a packed column.
Absorption in a bubble column. Absorption in a sieve tray
column.
7. SIMULTANEOUS HEAT AND MASS TRANSFER.
Drying. The wetted wall column. Air humidification in a
spray tower.
8. EXTRACTION. Extraction in a rotaing disc
column. Extraction in a reciprocating plate column. Ex-
traction in a mixer-settler.
9. OTHER UNIT OPERATIONS. Preparative gas
chromatography. Reverse osmosis. Crushing and grinding.
The experiments do not, of course, cover the whole
field of unit operations. The very important area of crys-
tallization is, for example, omitted. However, they should
ensure that the students come in close, practical contact
with a broad spectrum of chemical processing equip-
ment.
REMARKS
The experience with the course has generally
been good. The students and faculty seem to find
the course an interesting worth-while experience.
As mentioned above, one argument against a
course of this type is that using finished, fixed
experimental units does not leave much room for
student initiative. However, this was recognized
as a danger from the very beginning of the
planning, and attempts have been made to make
the course as interesting and challenging as pos-
sible in other ways. Where possible, large scale
glass equipment is used so that one may visually
observe the phenomena of interest. Adequate in-
strumentation has been provided so that many
tedious measurements are avoided and so that
the students may concentrate on the central prob-
lems (on the other hand, automation is kept to a
minimum as "push-button experiments" are not
desired). In addition, the fact that most of the
experiments are concerned with separation pro-
cesses, a specialty of chemical engineering, stimu-
lates interest.
(Continued on p. 152)


SUMMER 1973










AN EVOLUTIONARY EXPERIMENT


A. MEISEN
The University of British Columbia
Vancouver 8, B.C., Canada


M ANY CHEMICAL ENGINEERS are involved
in the development of industrial processes
which consist of several articulated operational
steps. Since data for such development are fre-
quently lacking and are only obtainable through
experimentation, the engineer must be capable of
devising experimental equipment and procedures.
The usual undergraduate laboratory courses
do not prepare the engineering student well for
such tasks. Most experiments are intended to
demonstrate a single rather than a sequence of
concepts or operations, and their interdependency,
which is so essential for industrial processes, is
not apparent. Since the experimental apparatus
is usually provided, the student is primarily re-
quired to follow an established procedure and
analyse his results. He plays virtually no role in
selecting the experimental equipment and tech-
niques.
Hence, in order to give students some experi-
ence with developing a process, an "Evolutionary
Experiment" was recently introduced into an ex-
isting, Senior laboratory course at UBC. The term
"evolutionary" suggested itself because students
worked on the process in turn and it thus evolved
during the academic year. The present note de-
scribes an Evolutionary Experiment on electro-
winning of copper and emphasizes the organ-
izational rather than technical aspects. This
approach was taken because the latter are thought
to be of less general interest.

ORGANIZATION
The class was divided into groups of three or
four students and each worked on the project for
two days spaced one week apart. Since only a
brief outline of the process was provided and
students were required to investigate all major
aspects in the course of the academic year, the
first group started by making a literature survey.
In addition it formulated a detailed work plan
and documented its findings in a technical report.
Subsequent groups always began by reading
previous reports and determining their specific


Axel Meisen received the BS degree from Imperial
College, the MS from Caltech and the PhD ('70) from
McGill University. His teaching and research interests
include air pollution control, process control, and design
of undergraduate experiments.

objectives commensurate with the general work
schedule. These decisions were discussed and
sometimes modified in a brief meeting with the
laboratory instructor before the groups pro-
ceeded. When experimental equipment had to be
built or modified, this could usually be accom-
plished during the week between laboratory
periods. The work of each group concluded with
writing a technical report and making recom-
mendations to future groups. The very last group
in the academic year prepared a summary report.

THE PROCESS
Due to time limitations, a simple process had
to be chosen and electrowinning of copper from
a leachable ore was selected for the first Evolu-
tionary Experiment in 1970. This process is quite
well understood and consists of three basic opera-
tional steps: ore leaching, purification of the leach
liquor and electrolysis to yield copper. A further
advantage of this process is the production of an
important, final product rather than an inter-
mediate requiring further chemical treatment.
The relevancy of this project was therefore
clearly apparent to the students.
Approximately 300 lbs. of ore were kindly
provided by the Anaconda Company from its
mine in Weed Heights, Nevada. The ore is readily
leachable with dilute sulphuric acid and yields a
liquor sufficiently strong for electrowinning. No


CHEMICAL ENGINEERING EDUCATION









The term "evolutionary" suggested itself because students worked on the
process in turn and it evolved during the year.


special problems of analysis arose since the acid
consumption and copper content of the rock or
leach liquor could be determined by titration and
atomic absorption spectroscopy, respectively.

ACHIEVEMENTS
Based on the literature survey prepared by
the first group, the second group decided that the
leaching operation should be conducted by either
percolating the acid upward or trickling it down-
ward through a fixed bed of ore. The important
variables were thought to be acid concentration
and flow rate. Temperature and rock size could
also be varied but were regarded as less signifi-
cant. The supplied rock was approximately -3
+5 mesh and was used in this form without
further crushing or screening.
The second group designed and assembled a
simple leaching apparatus whose main compon-
ent was a 3 in. ID, 2 ft. long glass column con-
taining the rock. The acid was delivered by a cen-
trifugal pump from a 10 gallon holding tank
through a valve and rotameter to the leaching
column from which it returned to the tank. The
piping, which consisted of polyethylene, was
arranged to permit operation in the percolation
and trickle modes. Samples of leach liquor were
withdrawn from the holding tank to determine
copper content and acidity.
Initial tests showed that the liquor flow rate
could not be kept constant and it was up to the
third group to rectify this problem. Careful ex-
perimentation revealed that small rock particles
became lodged in the valve thus restricting the
flow. After several other attempts which proved
unsuccessful, a by-pass was installed around the
pump. This allowed the valve to be opened more
fully and thereby reduced the chance of blockage.
The subsequent three groups studied the leach-
ing rate as a function of acid concentration, flow
rate and mode of operation. By applying Leven-
spiel's tests1, the results were found to be repre-
sentable by the unreacted-core model with the
major resistance to mass transfer lying in the
leached, outer layer of the rock particles. Hence
varying the flow rate and operational mode did
not significantly affect the leaching rate. The acid
consumption was almost stoichiometric with re-
spect to copper indicating that few other rock
constituents were attacked.


The sixth group was originally scheduled to
investigate purification of the leach liquor neces-
sary for electrolysis. However, since the iron and
particulate content of this liquor were unex-
pectedly low, the group concentrated on design-
ing an electrolytic cell and washing the leached
rock. The latter ensued from the realization that
copper sulphate adhering to the rock constituted
an economic loss and environmental hazard if
discharged. Washing with water was shown to
be complete in less than one hour.
The electrolytic cell consisted of a 3 in. by 5 in.
lead anode and similar copper cathode situated in
a rectangular, plastic tank. The spacing of the
electrodes was variable and the leach liquor was
continuously passed between them by letting it
overflow the anode and discharge through the
bottom of the cell. Poor liquor distribution re-
sulted and the evolution of gas bubbles interfered
with the electrolysis. These problems were re-
solved by the seventh group which modified the
cell by introducing the electrolyte at the bottom
and forcing it to flow upwards between the elec-
trodes. The effects of flow rate, electrode spacing
and current density on copper deposition were in-
vestigated and current efficiencies in excess of
90% were achieved.
The final group prepared a summary report
and indicated areas requiring further work.
Furthermore, it considered the problems asso-
ciated with scale-up of the laboratory data.

STUDENT REACTION
Student response to the Evolutionary Experi-
ment was quite favourable because it provided a
break from the more traditional laboratory work.
They enjoyed the flexibility of the project and the
ability to formulate their own objectives. Since
each group started where the previous one had
left off, the work seemed more original than
usual. Finally, students appreciated the oppor-
tunity to study an industrially significant process
and gain practical experience with developing ex-
perimental equipment.
Since each group worked on a different aspect
of the Evolutionary Experiment, students recog-
nized the necessity for clear and concise technical
reports. Needless to say, they were not overjoyed
by this realization, but it made the task easier.
(Continued on p. 147)


SUMMER 1973










A FORCED CONVECTION DEMONSTRATION

USING SOLID CO2 SUBLIMATION


D. A. MELLICHAMP and 0. C. SANDALL
University of California
Santa Barbara, CA 93106

One of the features of the transport processes
sequence presently taught to chemical engineer-
ing undergraduate students at UCSB is the
weekly laboratory which is used to illustrate
selected principles from the lectures. Experi-
ments performed during the laboratory period
usually take the form of a demonstration where
data are taken to be analyzed by the students in
an assigned home problem. In this way many of
the home problems cover a practical transport
problem involving the analysis of real data.
The department sub-sonic wind tunnel is used
for the majority of these demonstrations. Hence,
in the fluid dynamics course the demonstrations
start with simple air stream velocity measure-
ments, cover the standard demonstrations of
drag on a bluff object, boundary layers, etc. In
the course on heat transport, demonstrations
cover such topics as heat transfer from a cylinder
in transverse air flow.
In the concluding course dealing with an-
alogous mass transport phenomena, the difficul-
ties encountered in designing appropriate demon-
strations are significantly greater. The authors,
in a recent paper', described an experiment de-
veloped by students as a term project which
covers mass transfer from a cylinder in trans-
verse air flow. In this experiment the cylinder is
cast from naphthalene with a liquid nitrogen
quench to obtain a very fine grain structure at
the surface of the cylinder. The low sublimation
rate of naphthalene, even under conditions of
forced convection, requires running times in the
wind tunnel on the order of a full day to achieve
measurable material loss from the cylinder. The
advantage of the naphthalene cylinder experi-
ment, however, is that simple mechanical methods
can be used to measure accurately the rates of
mass transfer. These data can then be compared
to analogous data from heat transfer experi-
ments.


Obviously this experiment requires too much
time to serve as an effective demonstration. Con-
sequently, we have developed a complementary
experiment, utilizing a dry ice cylinder, to furnish
a rapid visual demonstration of mass transfer in
transverse air flow. Solidified carbon dioxide has
a much higher vapor pressure than most common
solids; hence, with a vastly increased driving
force for mass transfer, wind tunnel demonstra-
tions can be run in several minutes. A further
advantage of the use of a dry ice cylinder is that
normally there is enough moisture in the ambient
air which condenses in the vicinity of the cylinder
to provide effective visual evidence of boundary
layer formation and separation, vortexing in the
cylinder wake, and the flow patterns in the vicin-
ity of the rear stagnation point.
The experiment is quite simple to carry out.
A mount (shown in the accompanying figure)
supports the cylinder in the wind tunnel test sec-
tion. The mount is adjusted to hold the cylinder


Figure 1
Dry Ice Cylinder Mounted in Wind Tunnel.

CHEMICAL ENGINEERING EDUCATION























Orville C. Sandall is currently an assistant professor
in Chemical Engineering at the University of California
at Santa Barbara. He obtained his education at the Uni-
versity of Alberta (BSc, MSc) and the University of Cali-
fornia at Berkeley (PhD). His teaching and research in-
terests are in the areas of heat and mass transfer. (left).
Duncan A. Mellichamp is an assistant professor in
Chemical Engineering at the University of California at
Santa Barbara. He received the BChE at Georgia Tech,
studied one year at the Technische Hochschule Stuttgart
(Germany), and obtained the PhD at Purdue University.
His present interests are in the fields of process dynamics
and automatic control. (right).

in compression with dense foam rubber (in our
case, rubber backed carpeting) gaskets used to
insulate the cylinder from the mount and to
maintain the compressive force as the ends of
the cylinder sublime. Preparation of the cylinder
is very simple, if somewhat novel. An ordinary
three pound block of dry ice is set-up in our ma-
chine shop metal lathe. It is quickly turned to
the required diameter by standard machining
techniques and immediately brought to the wind
tunnel for the demonstration.
After mounting the dry ice cylinder in the
wind tunnel the air flow is turned on and is
quickly adjusted to correspond to the desired
Reynolds number. It was found that at prevailing
air relative humidities of approximately 50%, the
streamline patterns of condensed moisture were
clearly visible at air velocities of approximately
50 ft./sec. For the 2-inch diameter cylinders used
in the demonstration, this corresponds to a Rey-
nolds number of about 50,000. At this Reynolds
number the laminar boundary layer separates
before it becomes turbulent, the point of separa-
tion occurring at an angle of about 80 degrees
from the forward stagnation point. The stream-
line patterns clearly show the separation point
and the angle of separation is easily estimated
by the students to be at approximately 80 degrees


The department sub-sonic wind tunnel
is used for demonstrations in fluid
mechanics and heat and mass
transport phenomena.


fro mthe forward stagnation point. The stream-
lines in the downstream turbulent wake are also
clearly visible particularly near the rear stagna-
tion point.
After running the demonstration for about
five minutes the wind tunnel is turned off and the
dry ice cylinder may be inspected. This length of
time is sufficient for a protruding ridge to appear
at the separation point. This ridge indicates the
sharp minimum in the local mass transfer co-
efficient that occurs at the point of boundary
layer separation.

REFERENCE
1. Sandall, 0. C., and Mellichamp, D. A., "A Simple
Forced Convection Experiment", Chemi. Engi. Edu.
Vol. 5, 134-136 (1971).



MEISEN: (Continued from p. 145)

Report writing was further simplified by the fact
that students did not primarily write for the in-
structor but rather for their class-mates whose
technical competence they knew.

CONCLUDING REMARKS
Although it is clear that not all undergraduate
experiments should be replaced by Evolutionary
Experiments, the addition of one or two can con-
siderably enliven a laboratory course. In order to
maintain student interest, the topics should be
frequently changed. The following projects, which
have either been conducted or are planned at
U.B.C., may serve as further examples of Evolu-
tionary Experiments: production of crystalline
copper sulphate from an Arizona ore, extraction
of protein from fish meal, manufacture of fur-
furaldehyde from sawdust and recovery of metals
from scrap tin cans. The latter two projects were
initiated by Dr. K. B. Mathur and Dr. A. P.
Watkinson, respectively.

REFERENCE
1. 0. Levenspiel, Chemical Reaction Engineering,
p. 338, John Wiley and Sons, New York, 1962.


SUMMER 1973











AN INTEGRATED REACTOR ENGINEERING


LABORATORY



R. D. WILLIAMS
University of Arizona
Tucson, AZ 85721


Chemical Engineering is unique among other
engineering specialties in that its basis is in
chemistry. Since this is so and since chemical
rate phenomena are an important part of chem-
istry, the body of knowledge including not only
chemical rate phenomena but also the coupling of
such phenomena with physical processes is worthy
of intensive coverage in the training of chemical
engineers.
Two pressures familiar to academicians in-
volved in curricula review are the pressures from
outside the University (industry) to make the
curriculum more relevant and practical, and pres-
sures from inside the university to make the
curriculum attractive to interested students.
These two pressures are not complementary in
that the former results in the addition of new
experiments or new laboratories and hence tends
to increase the rigor of the curriculum whereas
the latter results in just the opposite.
At the University of Arizona we have at-
tempted to compromise these considerations in
the area of chemical reaction engineering by
integrating as much as possible of relevant prin-
ciples, concepts, and techniques from the theory
course into a one unit laboratory in the semester
following the presentation of the theory. As will
be brought out, the number of items deemed im-
portant for inclusion into the lab necessitates
careful selection of experiments such that each
covers several of these important items. It is in
this sense that the term "integration" is used in
this paper and not in the sense that the theory
and lab have been integrated time-wise. This
paper will first discuss laboratory objectives and
then illustrate their implementation by giving
specific examples of experiments being conducted.

OBJECTIVES
In 1969 we conducted a poll of 152 departments of
chemical. engineering, principally in the United States


and Canada. The response to the poll was high (102/152=
67%) so that meaningful conclusions may be drawn as
to trends across the country. Of the 102 responding de-
partments, 61 stated that they currently had some lab
experience in kinetics and 41 did not. Of those who did,
only 8 had labs completely devoted to the subject and of
those who did not the majority (33/41) anticipated the
addition of such experience in the future.
The responding departments indicated that their most
popular experiments utilized single phase systems in
batch, CSTR, and tubular reactors. Almost as popular was
the heterogeneous catalytic type of reaction conducted
in a differential tubular reactor with analysis by gas
chromatography. From this it may be deduced that the
demonstration of reactor behavior with simple (single
phase) systems is generally of highest priority and that
to illustrate more complex (heterogeneous) systems the
differential reactor is being used, presumably due to its
simplicity, ease of analysis, adaptability and compatibil-
ity with gas chromatography.
The objectives selected for our laboratory are:
*To complement the theory course with practical ex-
perience.
*To provide a variety of experience in reactor types,
types of reacting systems, methods of data collection,
methods of data analysis.
*To provide a laboratory environment in which some
degree of success is assured.
The specific experience areas from the theory
course which were desirable for the laboratory
were:
1. Reactor types.
A. Batch. Homogeneous isothermall, adiabatic).
heterogeneous slurry.
B. Continuous stirred tank.
C. Continuous integral tubular.
D. Continuous differential tubular.
2. Reacting Systems Types.
A. Homogeneous.
B. Heterogeneous catalytic.
C. Heterogeneous noncatalytic.
3. Data Collection Methods.
A. Direct rate monitoring. Titration. Gas chroma-
tography. Optical measurement.
B. Indirect rate monitoring. Temperature meas-
urement. Pressure measurement.
4. Data Analysis Methods
A. Integral method.
B. Differential method.


CHEMICAL ENGINEERING EDUCATION























Richard D. Williams has been at the University of
Arizona since 1968. He studied at Texas Tech University
(BS) and obtained his doctorate in Chemical Engineering
at Princeton University. His current area of specializa-
tion is chemical reaction engineering.

The experiments which have been run using
homogeneous systems are listed below. Each of
these four experiments is run by all the student
groups and collectively they occupy about one-half
to two-thirds of the course:
1. Batch kinetics determination by direct sampling.
2. Prediction and experimental verification of single
and multiple CSTR performance.
3. Prediction and experimental verification of
packed and unpacked tubular behavior.
4. Batch kinetics by an indirect method-the adiaba-
tic reactor.
The heterogeneous experiments which have
been implemented are given below. Each student
group will take one of these experiments as an
independent project for the time remaining at the
end of the semester.
1. Hydrogenation of nitrobenzene on Pd-charcoal in
a slurry reactor, with indirect pressure measure-
ment.
2. Dehydrogenation and dehydration of IPA on Pt--
charcoal in a continuous microreactor, analysis by
gas chromatograph.
3. Noncatalytic TCC catalyst regeneration.
Each of the experiments will now be briefly
discussed giving its advantages to the lab.

EXPERIMENTS-HOMOGENEOUS
The first experiment involves the verification
of a postulated reaction order and determination
of rate constant temperature dependence for a
homogeneous reaction in a batch reactor. To date
we have used the ethyl acetate saponification re-
action. Figure 1 is a schematic of the experi-
mental apparatus which consists of a constant


Fig. 1. Reactor Bench









temperature bath and a three liter glass-stainless
steel reactor. Data is typically collected by direct
sampling and titration. The methods of excess
and/or half-lives may be used but in any case an
integral method is used for data analysis. Our
experience indicates that many students lack
sufficient lab technique to get good results with
this experiment. In accord with our objective of
providing an environment to insure some success
and especially in light of time limitations we are
considering changing this experiment (and the
two to follow) to automate the analytical tech-
nique.
The second experiment has been the experi-
mental study of the transient startup of a CSTR
sequence. Figure 2 illustrates our reactor bench
in more detail. Reactants are contained in two
pressurized 5-gallon polyethelyene carboys and
are passed through coils in the constant temper-
ature bath before being metered into the continu-
ous reactor being studied. The experimental re-
sults may be checked against theory by using
the reaction rate expression developed in Experi-
ment 1. Degrees of non-ideality may be controlled
by changing mixing RPM, reactor baffling and
nearness of inlet and outlet ports.


Fig. 2. Reactor Bench Detail


SUMMER 1973









The third experiment uses the same feed
system as Experiment 1 but in conjunction with
a jacketed glass tubular reactor. In this experi-
ment steady state conversion is obtained as a
function of mean residence time for both an open
tube and with the tube packed with 1/4" glass
Raschig rings. These first three experiments all
conducted on the same reactor bench serve to
give the student a better understanding of how
mixing in a chemical reactor determines reactor
behavior. Other experiments which could be run
on this very adaptable apparatus include resi-
dence time distribution determinations and
demonstration of steady state multiplicity. These
experiments are currently being prepared for
future use.
The last homogeneous experiment run was
chosen for several reasons. It demonstrates the
operation of an adiabatic batch reactor with an
exothermic reaction. Unlike the isothermal ex-
periments which precede it, this experiment re-
quires that an energy balance be made for data
analysis. Further, since the coupled material and
energy balances are nonlinear the integral method
of analysis will not work. Fortunately, the differ-
ential method comes to the rescue and is fairly
accurate since the continuous temperature-time
trace may be easily differentiated. The reaction
used is that between hydrogen peroxide and sod-
ium thiosulfate and unlike the ethyl acetate
saponification reaction it has a nonobvious stoi-
chiometry which may be experimentally deter-
mined. Figure 3 is a schematic of the experi-
mental arrangement.


THERMOCOUPLE
COLD JUNCTION


500 ML BEAKER

MAGNETIC STIRRER


10-2



_d(Tdt
(F- T)


TEMPERATURE
RECORDER


Fig. 3. Apparatus for the Adiabatic Reactor.

In a typical experiment the reactants are
mixed together and the sigmoidal temperature
increase with time is recorded. The temperature
rise will depend on the volume of the reaction
mixture and the amount of limiting reactant
present. If the volume is held constant (at 400 cc
for example) and the initial reactant ratio is


3m
90
80
70
60
AT
(C) 50
40
30
20
10
0


0 1 2 3 4 5
VOUE OF 2 N H202 / VOUM OF 2 M NA2S203


6 7 8


Figc. 4. Temperature Rise as a Function of Initial Reactant Ratio.

varied then the temperature rise will go through
a maximum when the initial reactant ratio is
equal to the stoichiometric ratio. This is shown
in Figure 4 with student data from last year. The
different symbols correspond to different student
groups. From this graph it appears that of the
possible stoichiometrys listed, the appropriate
one is the last equation listed. Theoretically, it
can be shown that if the rate of temperature
change divided by the approach to the final tem-
perature squared is plotted against reciprocal
temperature an Arrhenius plot results (Figure
5). The experimental activation energy found
using student data compares very well with that


3,0 3.1 3.2 3,3 3,4
1000/T (K)-1
Fig. 5 Arrhenius Plot for Na2S2O0-H20, Reaction

CHEMICAL ENGINEERING EDUCATION


2 N2S23 +H202= N62 06 + 2 WH
% NA0.0l0= NA2SA+N2O
3 NA2S03 + 4 = 2 NA2%06 + 2 N'O + 3 H20
&2S203 4 2 + N0~ = 2 6O 4 + 50 H









reported in the literature as shown. Table 1 gives
a more complete list of experimental values ob-
tained from student data compared with litera-
ture values. The agreement is quite good.
TABLE 1 COMPARISON OF STUDENT A.D LITERATURE VALUES


-AH
kcal/mole
VAiB -a2S203


Student 2 142 7
Literature 2 142.5


ko
E liters/mole-
kcal/mole sec

18.7 7.33 x 1011
18.28 .3 b.85 x 1011


EXPERIMENTS-HETEROGENEOUS
The remainder of the experiments utilize
heterogeneous systems and each student group
will work with just one of these for the rest of
the semester.
An apparatus used to study the catalytic de-
composition of isopropyl alcohol (IPA) is shown
in Figure 6. Helium carrier gas is bubbled through


H Fig. 6. Microreactor. IPA dehydrogeneration and dehydration.
the IPA and then passes through a microreactor
containing Pt-charcoal catalyst. The reactor efflu-
ent may be sampled and analyzed by gas chroma-
tograph. IPA will decompose to give either pro-
pylene and water or acetone and hydrogen, de-
pending on reactor conditions, particularly tem-
perature. The temperature of the reactor is main-
tained by a sandbath and sampling is accom-
plished with a multiport sampling valve. This is
an easy experiment to run and demonstrates well
the reaction selectivity dependence on tempera-
ture, the use of a differential reactor for obtain-
ing initial rate data, and the use of a gas chrom-
atograph for analysis. The apparatus is very
flexible in that various different reactions and
catalysts may be used.
Another good example of a heterogeneous sys-
tem is the hydrogenation of nitrobenzene over


Fig. 7. Slurry Reactor. Hydrogenation of Nitrobenzene.
Pd-charcoal catalyst in a slurry reactor such as
depicted in Figure 7. We use a one liter Parr
autoclave with a gas storage volume and mercury
manometer though the experiment can be just
as well studied in glass as reaction pressures are
not high. Nitrobenzene and catalyst are charged
to the reactor before assembly. The air space over
the nitrobenzene is flushed with nitrogen and
then with hydrogen before pressurizing the sys-
tem with hydrogen by reference to the mano-
meter. To initiate the reaction, agitation is begun,
dispersing the hydrogen and catalyst into the
nitrobenzene. Hydrogen pressure is recorded as a
function of time from which reaction rate may


0,15





0.10

LN (P/P)



0.05


0 0 I I I I I I I I I I I
0 10 20 30
TIME (MIN.)
Fig. 8. Pressure ratio verses time and catalyst loading for nitro-
benzene18 hydrogenation.


SUMMER 1973
















0.10 -

Lu (PJ/P)



0.05 CATALYST LOADING -
= S0.5 GRAMS

0.05



0 10 20 :d
TIME (6IN.)
Fig. 9. Pressure ratio verses time and mixing rate for nitrobenzene
hydrogenation.

be calculated. Theoretically the expected behavior
is first order with the effective reaction rate con-
stant being dependent on temperature, agitation
rate, and catylyst loading. Figures 8 and 9 illus-
trate the type of data which is obtained. The first
order behavior is verified and rate constant de-
pendence on catalyst loading and agitation rate is
shown. Figure 10 summarized the results of
Figure 9, giving the reaction rate constant as a
function of mixer RPM. The high RPM asymp-
tote corresponds to chemical reaction rate control
and the low RPM asymptote results from a dif-
fusion controlled regime. Data at temperatures
other than room temperature would allow for the
determination of the activation energy and pre-
exponential factor of the chemical reaction rate
constant. Empirical correlations for catalyst load-


250


200

(MIN.)
150


100


I I


200 500 750 1000 1250 1500


Fig. 1. Effective


rate constant verses mixing rate for nitrobenzene
hydrogenation.


ing and RPM (or mixing power input) are also
possible alternatives.
Other heterogeneous experiments which are
currently under development include the high
temperature, noncatalytic regeneration of coked
Thermofor catalytic cracking catalyst and the
leach recovery of metals (e.g., copper) from their
ores.

ACKNOWLEDGMENT
In developing such a laboratory one should be alert
for experiments which others have developed which have
proven to be successful and which complement the lab-
oratory objective. In this regard, I must acknowledge the
use of ideas of Drs. James B. Anderson at Yale and
Gordon B. Youngquist of Clarkson They have been espe-
cially helpful in suggesting experiments which we have
used successfully.


FREDENSLUND: (From page 143)
The stated course objectives appear to have
been met satisfactorily, although improvements
in the course are still being-and will continue
to be-made. Before starting the design of a
course of this type, the purpose of the course
must be very clear, since the equipment design
may vary a great deal with the objectives. These
objectives are likely to differ somewhat from
department to department.


ACKNOWLEDGEMENTS
The author wishes to thank all colleagues in Lyngby,
Lund, and Trondheim, who have contributed to the de-
velopment of the course.

REFERENCES
1. Crosby, E. J., "Experiments in Transport Phe-
moment", Wiley, New York, 1961.
2. Fredenslund, Aage, "Experiments in Unit Opera-
tions", Den private Ingeniofond, Copenhagen, 1972
(270 pp. in Danish).


CHEMICAL ENGINEERING EDUCATION


CATALYST LOADI N
= 0.5 GRAMS


' I


I I


I I








Hes locked into

childhood by a disease that's

already licked.


What happened was measles. -5- .
Common measles. And what's -
tragic is that it should never have
happened at all.
To most people, measles is
simply a childhood nuisance. But
statistics don't bear them out.
During the height of the mea-
sles season, 10,000 children are
stricken every three days. 60 are
hospitalized, 10 develop inflamma-
tion of the brain, 3 become men-
tally retarded. And one dies.
There's just no excuse for this
disastrous waste. Since 1965, the
measles vaccine developed by Dow
has more than proved its worth. -
And the cost of immunization is.
low compared to the consequences ..
of the disease, the staggering
expenditure in medical care and
the enormous number of school
days missed.
But after several years of dra-
matic decline, measles is now gal-
loping back. Because even the
best preventive is powerless if peo-
ple refuse to use it.
The answer is not more of
our vaccine. There's already plenty
of that. It's community awareness
of the threat measles poses to our
children. And community action to
stop the disease in its tracks.
At Dow, we're concerned with
more than chemistry. We're con-
cerned with life. And despite our
imperfections, we're determined to
share its promise. Wisely.
For a booklet on measles vac-
cination and your children, write to: .77
The Dow Chemical Company, ':-- -
Midland, Michigan 48640. ... '


400,0^










HO


W


TO


MAKE YOUR FUTURE


OUT OF PAPER.


Paper. You might think it's almost
too simple to be interesting. News-
papers, napkins, towels, cups. Simple.
But have you heard about the paper
that's used as the core of high-impact
plastic laminates? Or the pre-lubri-
cated communication paper tape for
data-processing equipment? Or the
specialty papers with complex coat-
ings for keeping packaged foods fresh?
Or the 3-ply paperboard made with
polyethylene film, virgin pulp
and recycled pulp which
together create an
excellent moisture
barrier?
And did you know
about our chemical .
products that are used -


in environmental systems for air and
water purification? Or our specialty
chemicals used to make products in
almost any industry you name?
And about the research involved in
all this? The physical, organic and in-
organic chemistry? The physics, math-
ematics and biology? The mechanical,
chemical and electrical engineering?
At Westvaco, making paper is a
whole lot more than just making paper.
And that's why we're interested
in innovative, naturally
Curious people who
can see the future in
paper the way we do.
With them, we think
we can help shape the
S future for everyone.



Westvaco
299 Park Avenue
New York, N.Y. 10017


An Equal Opportunity Employer




Full Text
xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID E8XKY3F4Y_VDTQ4Q INGEST_TIME 2011-09-21T15:08:39Z PACKAGE AA00000383_00041
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES



PAGE 1

CEE clie ca: l! en gin ee ~ e ifu cation SUMMER 1973 VOL. 7, NO. 3 a heal Pui94 < g OF C w CALTECH ai:: w w z (.'.) z w ai:: 0 u.. >1w 8 (/) z <( u ix w u.. 0 z 0 (/) > 0 (.'.) z ai:: w w z (.'.) z w -' <( u w :c u CHE AT SUNY-BUFFALO SPECIAL LABORATORY ISSUE FOGLER, PERNA, SHAIR: Undergraduate CHE Laboratory SCHMITZ: A Computerized Process Dynamics and Control Lab SILLA: CHE Design Laboratory ROUSSEAU, GARDNER, FELDER: Flow Modeling and Parameter Estimation DE NEVERS: Bernoulli's Equation with Friction FREDENSLUND: A New Traditional Unit Op Lab Course WILLIAMS: An Integrated Reactor Engineering Laboratory MEISEN: An Evolutionary Experiment MELLICHAMP & SANDALL: A Forced Convection Demonstration RUSSELL & DENN .,~ /,a. e1,,c .,ti~

PAGE 2

ACKNOWLEDGMENTS INDUSTRIAL SPONSORS: ~lie c~t luwe JtmdeJ /u,HJd, jM IJw d-upruvd o/J CHEMICAL ENGINEERING EDUCATION JIVUIUj 1973: C F BRAUN & CO MONSANTO COMPANY THE 3M COMPANY DEPART ME NT AL SPONSORS: ~lie /ol,l,omuu; t .29 Jepalliinena luwe /,a. IJw o/J CHEMICAL ENGINEERING EDUCATION i,11, 1973 University of Alabama University of Akron University of Alberta Arizona State University University of Arizona University of Arkansas Auburn University Brigham Young University University of British Columbia Bucknell University University of Calgary University of California (Berkeley) University of California, Davis University of California (Santa Barbara) California Institute of Technology Case-Western Reserve University City University of New York Clarkson College of Technology Clemson University Cleveland State University University of Colorado Colorado School of Mines Columbia University University of Connecticut Cooper Union Cornell University University of Delaware University of Detroit University of Denver Drexel University Ecole Polytech, Canada University of Florida Georgia Institute of Technology University of Houston Howard University University of Idaho University of Illinois (Urbana) Illinois Institute of Technology Iowa State University University of Iowa University of Kansas Kansas State University University of Kentucky Lamar University Laval University Lehigh University Loughborough University (England) Louisiana Polytechnic Institute Louisiana State University University of Louisville McGill University McMaster University McNeese State University University of Maine Manhattan College University of Maryland Massachusetts Institute of Technology University of Massachusetts University of Michigan Michigan State University University of Mississippi University of Missouri, Columbia University of : Missouri, Rolla Montana State University University of Nebraska Newark College of Engineering New York University University of New Mexico University of New Brunswick University of New Hampshire University of New South Wales New York University North Carolina State University University of North Dakota Northwestern University University of Notre Dame Nova Scotia Technical College Ohio University Ohio State University University of Oklahoma Oklahoma State University Oregon State University University of Ottawa University of Pennsylvania Pennsylvania State University University of Pittsburgh Polytechnic Institute of Brooklyn Princeton University University of Puerto Rico Purdue University University of Quebec Queen's University Rensselaer Polytechnic Institute University of Rhode Island Rice University Rutgers-The State University University of Rochester University of Southern California South Dakota School of Mines State University of N. Y. at Buffalo Stevens Institute of Technology Syracuse University Technion, Israel Tennessee Technological University University of Tennessee Texas A&I University University of Texas at Austin Texas A&M University University of Toledo Tri-State College Tufts University University of Tulsa University of Utah Vanderbilt University Villanova University University of Virginia Virginia Polytechnic Institute Wayne State University Washington State University Washington University University of Washington University of Waterloo West Virginia University University of Wisconsin Worcester Polytechnic Institute University of Wyoming Yale University Youngstown State University University of Windsor TO OUR READERS: If your department is not a contributor, please ask your department chairman to write R. B. Bennett, Business Manager, CEE, Depart ment of Chemical Engineering, University of Florida, Gainesville, Fla. 32601. Bulk subscription rates at $4 / yr each with a $25.00 minimum for six or fewer subscriptions. Individual subscriptions are available to ASEE-CED and AIChE members at $6 yr.

PAGE 3

EDITORIAL AND BUSINESS ADDRESS Department of Chemical Engineering University of Florida Gainesville, Florida 32601 US ISSN 0009-24 7 9 Editor: R ay F a h ien Associate Editor: Mack Tyner Business Manager : R B. Bennett (904) 392 086 1 (904) 392-088 1 Publications Board and Regional Advertising Representatives : SOU TH : Charles Littlejohn C h airman of Publications Board C l emso n University Homer F Johnson Univers i ty of Tenllssee Vincent W Uhl Univers i ty of Virgi n ia CEN T RAL: Lesli e E Lahti University of To l edo Camden A. Coberly University of Wisconsin WEST: William H. Corcoran California Institute of Technology George F. M eena ghan T exas Tech University SOU T HWEST: J. R. Crump Univers i ty of Houston James R. Couper University of Arka n sas EAS T :G Micha e l Howa rd University of Connecticut L eon Lapidu s Princeton University Th omas W Weber St a t e U niversity o f N ew Yo rk NORTH : J J. Martin Uni ve rsit y of M i c hi gan Julius L. Jackson Wayne State University Edward B. Stuart University of Pittsburgh NOR TH W EST : R. W. Moulton Uni versity of Wash i ngt o n Charles E. Wicks Oregon State University PUBLIS H ERS RE P RES E NTATIVE D. R C o ughanowr D r e x el U n i versi ty UNIV E RSIT Y REPRESE N T A TI V E S tuart W. Churchill Uni vers i ty of P en n sy l va n ia LIBRARY REPRESENTATIVES UNI V ERSITIES : J ohn E Myers Uni ve rsity of California SUMM ER 1 97 3 Chemical Engineering Education VOLUME 7 NUMBER 3 SUM M ER 1973 Departments 106 The Educator P r o fessor C. J Pings 112 Departments of Chemic a l Engineering SUNY at B uffalo, J. G Vermeychuk and J A. Bergantz 117 The Classroom I ntroduction to ChE Analysis, T.W F. Russell and M M Denn 142 International Chemical Engineering A Ne w Traditional Unit Operat i ons Laboratory Course, Aage Fredenslund 110 Book Reviews Special _al,.o,,_a,to,,,_'I 1 &.due 122 T h e Undergraduate ChE Laboratory, H S. Fogler, A T. Perna, and F. H. Shair 126 Bernoulli's Equation with Friction, Noel de Nevers 129 The ChE Design Laboratory, Harry Silla 132 F l ow Modeling and Parameter Estima tion Using R adiotracers, R. W. Rousseau, R. P. Gardner, and R. M. Feld er 136 A Computerized Undergraduate Process Dynamics and Control Laboratory, R. A. Schmitz 144 An Evo l utionary Experiment, A Meisen 146 A Forced Convection Demonstration Using Solid CO2 Sublimation, D A. Mellichamp and 0. C. Sandall 148 A n Integrated Reactor Engineering Lab oratory, R D. Williams CHEMICAL ENGINEERING EDUCATION is published quarterly by the Chemical E ngineering D ivision. American Society for Engineering Education. The pub1ication is edited at the C h emica l Engineer i ng Department, University of Florida. Second-class postage is paid at Gainesville, Florida, and at DeLeon Spring s, Florida. Correspondence regarding editorial matter, circulation and changes of address should be addressed to the Editor at Gainesville, Florida 32601. Advertising rates and information are available from the advertising representatives Plat es and other advertising material may be sent directly to the printer: E 0 Painter Printing Co P. 0. Box 877 DeLeon Springs, Florida 32028. Subscription rate U.S., Canada, and Mexico is $10 per year, $6 per year mailed to members of AIChE and of the ChE Di vis ion of ASEE, and $4 per year to ChE faculty in bulk mailing. Write for prices on individual back copies. Copyright 197 3 Chemical Engineering Division of American Society for Engineer i ng Education Ray Fabien, Editor. The statements and opinions expressed in this periodical are those of the writers and not necessarily t h ose of the ChE D ivision of the ASEE which body assumes no responsiMlity for them D efective cop i es replaced if notified within 120 days Th e International Organization for Standarization has ass i gned the code US ISSN 0009-2479 for the identific ation of this periodical. 105

PAGE 4

Ci Na educator ALIAS NEAL 'PINGS* JACQUELYN HERSHEY California Institute of Technology Pasadena, CA 91109 Once upon a time a university professor could, with a clear conscience, hew to his schol astic specialty and let administrative chips fall where they might. But at Caltech those days are long gone. In fact, it's a rare scholar who doesn't have an administrative assignment outside his classroom and lab. But "rare" is hardly adequate to describe a man who takes on three or four. Take C. J. Pings, professor of chemical en gineering and chemical physics, who is also execu tive officer for chemical engineering, vice provost, and dean of graduate studies. Membership in a clutch of committees and professional societies, co-editorship of the journal Physics and Chemis try of Liquids, and editorship of a new journal Chemical Engine e ring Communications round out his multifaceted and admirable career. Admirable, that is, except for his troubles with the FBI. This blot on the escutcheon of someone who has risen to such heights at his alma mater-and become a highly respected scientist elsewhere as well-dates back to 1951 when Neal was a senior at Caltech. Though he had acquired the name "Cornelius" at birth in 1929 (via his father, his great-grandfather, and his mother's sister Cornelia), he had adopted "Neal" for all practical purposes. But the solemn ity of a possible job with the Atomic Energy Commission after graduation led him to inscribe "Cornelius" on his application. The AEC sent a standard request for a recommendation to chem'' 'Based on an article in Engineering and Science magazine, October 1972. Published by Th e California Institute of Technology. 106 istry professor Ernest Swift. His crisp reply that he had never heard of any Cornelius Pings brought a swarm of FBI agents buzzing around Neal's hapless head. "Living under an alias was over," says Neal. "Before applying for any more jobs, I knew I had to make the switch from Neal to Cornelius. I started by going to the Registrar's office to get my name changed on my transcript-and that's when I found out my troubles had just begun. There was no way, I was told, to make the change I produced my birth certificate; the Registrar's staff was not impressed. I admitted that I had lied about my name when I entered Caltech; they suggested I get a court order for them to make the alteration. I think we finally compromised by putting Cornelius in parentheses on the records Cornelius John Pings is a native of Conrad, Montana, a small rural community on the east side of the Rockies. His family lived in Montana because his grandfather had left the family home in Wisconsin to take out a homestead in the West. (A generation earlier his great grandfather had immigrated to the United States from Germany, about the same time that his mother's ancestors arrived from Ireland.) Neal's father struggled through the Depression years as an electrician with the Rural Electrification program, and finally in 1942 went looking for his greener pas tures in California. Those early years of economic insecurity gave Pings some sturdy opinions about what an educa tion is for. The quest for knowledge excited him, but a strong motivation for getting a college de gree was its promise of economic benefits. Neal entered Caltech planning to become a nuclear physicist-an ambition that lasted just one term. But chemistry immediately filled the CHEMICAL ENGINEERING EDUCATION

PAGE 5

Neal had a headon verbal collision with the dietitian. J I void-perhaps, he suggests, partly because of the quality of instruction he received. Linus Pauling and Norman Davidson taught him freshman chemistry, and Ernest Swift was his instructor in sophomore year. ("Anyone who survived that course will testify to its intellectual thorough ness.") Howard Lucas, professor or organic chemistry, taught him most of what he knows about laboratory techniques. With visions of going to work eventually for a chemical or petroleum company, Neal took his BS in applied chemistry-having financed four years of college with a combination of scholar ships, summer jobs, and student loans. And with the hope that this eventual job would be one of substantial technical responsibility in industry, he persisted through a PhD program in chemical engineering. It was with some surprise, then, that in 1955 he found himself turning down some attractive job offers in industry to go with his fellow alumnus Dave Mason, then on the staff at JPL, to set up a new CHE department at Stan ford. "I decided to try academic life for one year," he says, "and I've been at it ever since. So much for my industrial aspirations. But I often tell students about myself when they ask me for career advice. My experience is that flexibility is an asset." Neal will testify that a little flexibility can take a man a long way-to northern Greenland, for instance. Thanks to his reading a notice posted on a campus bulletin board, that's where he spent the summers of 1955, '56, and '57 Grad uate student Mark Meier, now a noted authority on glaciers, was organizing a geology field trip and recruiting a staff. SUMMER 1973 "There's a component of engineer in me but I wanted to go into the hard science aspects of the liquid state ... Now, the problems are far from solved, but I think we've made some progress." Right then, Neal liked what that job offered summer work, distance from Pasadena, outdoor life, and moderately good pay. It also made good use of his research background (heat transfer 3-CHEM ENG-10 cent on 12-20 11957 Bill and thermodynamics) and he is still proud of three professional papers resulting from the ex perience. ("And my children are still young enough to be impressed when I point to Green land on the globe and say, "I was there.' ") After four years at Stanford, Neal came back to Caltech in 1959 as associate professor and as resident associate for Fleming House. Two prob lems cropped up soon after he arrived. The first was overcoming his student-bred reticence at calling senior faculty members by their first names. Will Lacey, now professor emeritus, cured that difficulty with a few well-chosen words. "You've graduated from calling me Doctor," he said. "My name is Will!" He and Marjorie were married in 1960 .... c.:....:.._ _, __ -'"'3,-i The other problem was that hardy perennial -complaints about student-house food. As resi~ dent associate, Neal had a headon verbal collision about it w ith the dietitian and manager of the student houses. Marjorie Cheney. His recollec tion of the effectiveness of his battle in behalf of an improved cuisine is hazy. ( Marjorie says: "At first I thought that he would be easier to cope with than the undergraduates, but .. !") One result was an "honest-to-God campus ro mance.'' He and Marjorie were married in 1960. 107

PAGE 6

Neal made a decision in his first year at Stan ford about the general area of research he wanted to pursue-to understand liquids at the molecular level. He was struck by the fact that a fairly sizable body of knowledge existed about gases and solids, but comparatively little about liquids. "There's a component of engineer in me," he says, "but I wanted to go into the hard science aspects of the liquid state. M y experiments have been designed to lead ultimately to better theory which may then be ap plied to practical p rob lem s Now, 16 years after I started, the problems are far from solved, but I think we've made some progress." Neal and his research group are currently in terested in mixtures. Understanding mixtures by the brute force of numbers of experiments is hopeless; there are too many possibilities. The aim is to develop some rules for utilizing what is known about simple substances to say how they will behave when they are combined. Essentially, the research is divided into three sub-groups, e ach involving use of a different technique and the simplest available systems (monatomic rare gases such as argon and kryp ton, which are liquid at the temperatures and pressu res used in the experiments) The technique Neal started working with, which is still the backbone of his research, is that of X-ray diffraction. Using it, his students are able to measure the structure of fluids-the aver age number of neighboring atoms and their dis tance apart. The second technique is a study of the refrac tive index of fluids, chiefly between liquid and gas. The refractive index is a measurement of how much a beam of light is bent as it stabs through a liquid. The amount of bending is indicative of the electrical environment of local areas of the liquid and also gives some ide a of its dens ity. The third technique is to use lasers for light scattering to study the motion of the molecules in fluids. This is fairly new, and with it Neal says, "We c a n make some very exciting measurements and get some wholly new information. And we don't yet have any idea of its full potential." While the orientation of Neal's research group is basically experimental, he makes sure that they keep in touch with theoreticians. "We try to find experiments to challenge or confirm the theories we he ar about," Neal says. "Then, from our data, we are able to suggest new approaches to the theoreticians, and we listen 108 Admirable, except for his troubles with the FBI .. when they suggest what we should be doing in the laboratory." Of course, Neal doesn't listen to just the local theoreticians. He is a regular participant to scien tific meetings, including the Gordon conferences. The Gordon Research Conference on the Physics and Chemistry of Liquids meets b ienniall y, and Neal has attended the last seven of them. (He was chairman of the one in 1969). Attendance is limited to 120 researchers, carefully chosen for a good mix between already established and younger scientists. "Those conferences are a beautiful experience," Neal says. "For one whole week you're with your colleagues -theoreticians and experimentalists-in continuing conversa tion. And we correspond over the intervening months too-asking questions, checking results, making suggestions I grumble a lot about meet ings, but not about these." Bringing ability and good nature to his meet ings, Neal makes both friends and progress in the process. Some of his success must surely stem from his genuine commitment to Caltech and to higher education. "I want to do what I can to help both of them thrive, to adapt to changing times, and to stay ahead of their problems," he says. Neal has taken some razzing about the num ber of jobs and titles he carries, but he doesn't feel that his case is noteworthy. "A lot of people around here are carrying administrative tasks and practicing the trade simultaneously," he says, "and it's not all that hard. The bureaucracy is minimal, which makes it possible to get hold of people and talk things out. Of course, you have to make choices. I regret losing some of the rapport I used to have with undergraduates. I missed teaching last year, so I'm glad to be back at it now-giving the thermodynamics course. I suppose there's some ham in me, but to stand CHEMICAL ENGINEERING EDUCATION

PAGE 7

up in front of a class and feel you're conveying knowledge and maybe affecting attitudes can be very satisfying. But I won't go into class half prepared." Juggling the requirements of his various posts and his available time also keeps Neal from getting into the lab to make his own measure ments. But he meets with his research group (smaller in these days of funding difficulties than it used to be) as often as he can, and he makes himself available for conferences on individual problems. The formalities of setting up such meetings are a little more complex than they once were, but he feels responsible for keeping track of what's going on and trying to be helpful. William Corcoran, professor of chemical engi neering and vice president for Institute relations, who has known him since 1952, puts the matter succinctly: "Nobody ever gets short changed by Neal." The list of Neal's contributions over the years on many Caltech administrative and faculty com mittees is a long one, and his chairmanship of the Ad Hoc Committee on the Aims and Goals of the Institute (1969-1970) epitomizes that kind and degree of service. Rodman Paul, Harkness Pro fessor of History, who has known Neal since he taught him history as an undergraduate, was also a member of that committee. He recalls that through all the long months of its deliberations Neal "displayed tremendous fairness, calmness, and breadth of understanding. He is a good scien tist who deals with human beings in human ways. When Harold Brown was chosen as president of the Institute, it was clear that somehow he would have to be thoroughly briefed. It was Neal more than anyone else who pointed out that the report of the Aims and Goals Committee would be ex actly what was needed to do the job. So, we shoved it through with a speed that didn't seem possible, and gave it to the president. I think it was the most thorough analysis and appraisal of Caltech that has ever been made." Neal says, "Working on that committee con vinced me-and others-that an institution like this doesn't run itself. We're fortunate here that the faculty is involved in decision making. It was clear at the time the committee was appointed that we were heading into a period when we were going to be subject to severe constraints, that we were going to have to live by our wits. There were going to be choices and decisions, and if the faculty wanted to get in on those, it was going to SUMMER 1973 Neal's administrative posts include executive officer, vice provost, and dean of graduate studies. have to make its views known and some of its members available for administrative positions. It's probably not a coincidence that 60 percent of the committee's members have ended up in ad ministration." Neal's own administrative posts include being executive officer for chemical engineering, vice provost, and dean of graduate studies. One reason he continues as executive officer is that the chemi cal engineering faculty is, on the whole, very young and involved in starting their own research. "It doesn't make sense to dilute their time with administration at this point," says Neal. "We're really victims of our own strategy, because we have deliberately been recruiting young men but it will pay off in the long run." Most of the day-to-day operations of the grad uate office-admission and support of students, management of the office, direct contact with the various option representatives, and participation in national and regional groups concerned with graduate education-have been turned over to Associate Dean Stirling Huntley, with Neal being involved in policy making, budgeting, and work ing with the Graduate Studies Committee. As vice provost, he has specific responsibility for all new and renewal appointments on the re search ladder, for the faculty portion of the Insti tute's Affirmative Action Program, for the library and the Industrial Relations Center, and for in terdisciplinary programs. Basically, however, he sees his task to be relieving the load carried by Provost Robert Christy. Somewhat ruefully he points out: "We have to handle questions that once didn't even arise: How do you try to do as much and maybe more, research on less money? How do you keep a young faculty when you can't afford to appoint new people? "There are lots of kinds of jobs around here, and I like to sample them," says Neal. "I enjoy 109

PAGE 8

feeling useful; I like to free time for others to do what they want to do. And there's enough of the competitor in me that I don't mind working at being successful. Each of my jobs calls on differ ent talents, responses, parts of temperament, and combinations of whatever abilities I have. And each makes vulnerable different kinds of short comings. Research demands analytical thought processes plus whatever creativity I have, and that rather severely exposes the limits of my in tellect. Supervision of personnel and administra tion in general require exercising judgment on problems dominated by values and the ramifica tions of human personality. I often find myself failing in these situations-either because I try to find an exact answer to a diffuse problem or, at the other extreme, I compromise in making a difficult decision because I give in to a desire to be liberal or compassionate." Administrative work is harder than either teaching or research as far as Neal is concerned -a fact which, he thinks, may reflect his lack of training in its techniques. The problem boils down to persuading other people to do things for him and he attacks it by assuming that the people he deals with are reasonable individuals. Like many another Caltech professor, Neal often takes a loaded briefcase home Even when he leaves his work at the office, he finds it hard to take a real break from his duties unless his family can lure him out of town-pref er ably to the mountains or the beach He feels that he is overdue for a leave of absence for about six months at another university. Such breaks in routine lend perspective But he expects the ex perience will just confirm his co-wiction that Cal tech really is an outstanding place. He has been investing in that conviction for a long time. As an undergraduate Neal Pings was a member of the Beavers, the Board of Control, the Interhouse Committee, Throop Club, and with real devotion-the varsity football team. All this adds up to top-notch credentials for his elec tion to the board of directors of the Alumni Asso ciation. He took on this three-year job in 1970 not only because he was interested but because he had a two-way feeling of responsibility He be lieves the faculty hasn't made adequate use of the talents of the alumni, and that the alumni could do a lot more for Caltech As a man with a foot in each camp, he thinks he may be able to im prove communications between the two groups. 110 If Neal's services as vice chairman of Pasa dena's Community Redevelopment Agency seem tangential to the academic circle in which he usually operates, the appearance is only super ficial. He's not there as an official representative of Caltech, but he points out: "I'm concerned that 20 years from now Caltech will be located in a city where it's still pleasant to live and to send children to school. The decisions that are being made right now will affect that. Faculty members here have always been involved in national affairs, but local involvement is just as important. Caltech can't isolate itself from Pasadena and maybe I can be a bridge." Not even the FBI could find anything wrong with that. [i) N pll b oo k rev iew s Introduction to Chemical Engineering Analysis, T W. F. Russell and M. M. Denn, 502 pp., John Wiley and Sons, Inc., New York, 1972 Do not be misled by the title of the book: this is not just another textbook for an introductory stoichiometry course. The fundamental approach is that of an integrated view of the entire typical chemical engineering curriculum The authors have decided that it is time to use something other than furnaces and sulfuric acid plants to form the background for such an introductory course. Their choice is the fluid filled vessel, in many of its ramifications. Real chemistry is used throughout. Those familiar with the structure of the chem ical engineering curriculum will find that there are several mini-texts included here. Kinetics, design, extraction, reactors, energy balances, pro cess dynamics, and mixing are all present. The introduction does a good job of intriguing the student, and the second and third chapters form a reasonable introduction to modeling principles There is also a chapter on data analysis in the midst of other topics. The first law of thermo-energy balances is covered well. There are accompanying mini-texts on convective heat transfer, non-isothermal re actors, and gas behavior. Perhaps of more interest to the potential user is what is not in this book. There is no sepa rate treatment of material balance principles. (Continued on p. 128) CHEMICAL ENGINEERING EDUCATION

PAGE 9

Over half the towns in the United States are forced to dump their wastewater in our rivers. The reason is sad. Money. Literally over half our towns haven't got enough money to build com plete wastewater treatment plants. And many towns that have complete plants aren't cleaning the water thoroughl y because the towns have outgrown the plants. And they can't afford to expand. So, because of money, towns are forced into polluting our streams and rivers. Union Carbide has discovered a new wastewater system that costs less. It's called the Unox System It's the first substantial change in wastewater treatment in thirty years Instead of the conventional aeration sys tem that cleans water by mixing it with the air, Unox forces pure oxygen into a series of closed treatment tanks This forc ed oxy gen technique cleans wastewater in les s time, l ess space and reduces the total cost up to forty percent It means a town can boost its wastewater system by simply adapting the Unox Sys tem to the exi s ting syste m. And towns with limited means can now afford a complete system. A number of cities and industries through out the country have already chosen the Unox System. And more installations are being planned. We've discovered a cheaper way to treat wastewater because our streams and rivers can't afford to wait. THE DISCOVERY COMPANY 270 P ark Av e ., New York N Y 1001 7 Fo r a dditi ona l information o n o ur ac tivit ies, w rite t o U n io n Ca rbide Corporation, Dep anmc nt of U ni ve r si ty Re lations, 270 Park Avenue New York New York 10017 A n equal oppo rtunity e mployer.

PAGE 10

SUN'/ A T BUFFALO J. GREGORY VERMEYCHUK and JOSEPH A BERGANTZ In a brief existence spanning but a dozen years, the Department of Chemical Engineering at the State University of New York at Buffalo, which began with a faculty of three and a hand ful of students, has rapidly developed into a full scale operation with thirteen facu l ty members and a sizeable graduate program Buffalo's ChE department is the only such department in the State University of New York. The SUNY system comprises four major graduate centers, many four-year Colleges, a multitude of two year insti tutions, and a number of special purpose installa tions. The entire system serveJ approximately 115,000 students, while the graduate center at Buffalo, including its noted medical school, has an enrollment of 22,000, distributed among two major campuses and a collection of other sites throughout the city and its environs. On a 1000 acre site to the North of the city, construction proceeds apace on a totally new, $650 million campus. This, and a number of other fac tors, suggest a period of continued growth for our department. The Department of Chemical Engineering is one of six engineering departments in the Faculty of Engineering and Applied Sciences. FEAS and six other F ac ulties constitute the University Cen ter at Buffalo Due to the nature of this form of organization, students and faculty can work within the atmosphere of a small engineering 112 school, yet have the tremendous diversity and varied human and material resources of a major university within easy reach. THE STAFF AND I TS ACTIVITIES It is a truism that the quality of an academic department may be gauged by the qualifications of each facu l ty member. The staff of our depart ment incorporates expertise in all the c l assical areas of ChE, and in a number of specialized areas related to ChE, such as process metallurgy, environmental and biomed i cal eng i neering, and modern control theory The facu l ty maintains an extensive and productive program of research, as indicated by approximate l y 50 journal articles published during the 1971 72 academic year. Several books and edited conference proceedings by faculty have a l so appeared during the past two years. Since our departmental faculty is drawn from a range of educational backgrounds (three of our number received the Ph.D. degree in phy:;;ical chemistry), joint research projects crossing de partmental bounds are inevitable. Many of our research publications result from collaboration with cell biologists, mechanical engineers, physi cians, geologists and chemists In addition to the usual man to man research co ll aboration, the structure of the University allows the development of more formal means of interdisciplinary academic activity. A Center for Process Metallurgy was formed in 1969 to per form research on problems related to the steel and other metallurgical industries. Two of the three professors involved in the center, including the director, are members of the Department of CHEMICAL ENGINEERING EDUCATION

PAGE 11

In ... but a dozen years, the Department which began with a faculty of three has developed into a full-sized operation with 13 faculty members and a sizeable graduate program. Chemical Engineering. This Center, in addition to funding provided by industrial firms, has re ceived a grant from the NSF / RANN program for the investigation of the applications of optimiza tion to the steel industry. Three chemical engineers are members of the Center for Theoretical Biology, which carries on investigations in many diverse areas germane to the biological sciences, and which publishes the Journal of Theoretical Biology. Two other mem bers of our faculty have provided papers pub lished in this journal. Another member of our department founded and has served as Master of the Rachel Carson College, an established undergraduate center for the study of modern technology and its impact on the environment. For the area of undergraduate and graduate teaching, our department is comparably active. Innovation in teaching has been an important theme. Two noteworthy new courses appearing in the present academic year are a lower division offering in Introduction to Chemical Engineering providing a modern approach, and a graduate course in the Applications of Immobilized Enzymes. ChE faculty members also serve as instruct ors in FEAS-wide sophomore level courses in thermodynamics and materials scie nce. These two courses provide the basic introduction to these topics for all engineering students within the University. The matter of undergraduate advisement ranks high in importance. Advisement seminars are presented to all engineering freshmen, and an extensive advisement brochure assists our undergraduates in tailoring their individual pro grams to specific needs. Perhaps the best way to provide an in-depth look at our department is to consider each mem ber of our faculty on an individual basis. JOE BERGANTZ is the man responsible for the crea tion of the department and served as our first chairman. In this position, Joe hired most of the present faculty. Additionally, he has served as Acting Provost of the Faculty of Engineering and Applied Sciences. Joe's cur rent research interests lie in the investigation of gas solid reactions which can be used to purify manufac tured gaseous fuels (i.e., resu ltin g from the gasification of coal) without loss of thermal efficiency. SUMMER 1973 Joe Bergantz: the man responsible for creation of the department. DON BRUTV AN, one of the original members of the department, now holds but a one-eighth-time appoint ment, since his prime function lies in University Admin istration. Don is Associate Dean of the Division of Con tinuing Education which serves some 6500 students, in both credit-carrying and credit-free programs HARRY CULLINAN, our present chairman, joined the department in 1964. Harry is continuing his experi mental program for the determination of selected liquid phase diffusion coefficients. This program makes use of a novel ultracentrifugal equilibrium sedimentation tech nique for the determination of the composition deriva tives of chemical potential for multicomponent liquid mixtures. He is also conducting theoretical work to show how the principles of non-equilibrium thermodynamics apply to the solution of coupled transport phenomena. During 1972-73, Harry has been on Sabbatical leav e at the University of Manchester Institute of Science and Technology, Manchester, England. PAUL EHRLICH, a physical chemist by training 1 tea~hes both graduate and undergraduate courses in poly mer materials, polym erization, and thermodynamics. Paul has completed experimental measurements and a theoreti~ cal ruialysis of the volumetric properties of ethane-n-hep tane mixtures in the supercritical region, including the vi cinity of the critical locus, and plans to extend his work to other paraffi n mixtures. Plans are also underway for new studies of the observed divergence from classical predic tions of thermodynamic and transport properties of ma terials at the critical-locus. Paul also has completed an ESR study of crystallizable, high-molecular weight polythenylacetylene. This work promises to be of sig nificance in the design of improved polymeric semiconduc tors and photoconductors. 113

PAGE 12

Bill Gill Provost, also supervises two po s t-doc s and n i n e gr a duate stud e nts BILL GILL, who joined us in September, 1971, is Provost of FEAS. The heavy administrative load has not impeded his program in teaching and research, however, Bill currently supervises a group of two post-docs and nine graduate students. With R. Sankarasubramanian, he continues the development of a new solution technique for convective diffusion problems by generalization of their original approach to dispersion problems to include interphase transport and chemical reaction. Bill and M. Doshi are working on a countercurrent ion exchange unit and have succeeded in markedly increasing the efficiency of such units. This work has led to a simple model which seems to explain the effects of bypassing quite adequately. He is studying both theoretically and experimentally the properties of tubular and hollow-fiber reverse osmosis systems. Experimental work with L. Derzansky has shown that natural convection in tubu lar R. 0. systems has a significant bearing on perform ance. An analysis of hollow fiber systems has led to an approach to optimal design which appears to hold promise. In collaboration with GREG VERMEYCHUK a study is underway on the oxygenation of liquids in open channel turbulent flow. Greg and Bill are preparing an iexperimental study of the effectiveness of diffusion boundary layer withdrawal in the improvement of per formance in R. 0. systems. Alternating sections of selec tive and non selective membranes will be used. Another physical-chemistry trained member of our department is BOB GOOD. Bob has recently shown that certain anomalies in the rate of penetration of a liquid into a porous body such as a bed of powder, or a capillary, can be explained with the aid of a generalization of the Washburn equation for capillary flow. He has discovered an anisotropic effect in the wetting of stretch-oriented polymers, and a heat effect in the peeling of a pressure sensitive tape. He has developed a general theory of the contact angles of liquids on solids and has very recently published a theory that is an important advance in the understanding of interfacial separation in adhering sys tems. He has shown that the adhesion of living cells to each other in tissues is due to forces that physical chemists and chemical engineers have been studying for a number of years, with respect to the stability of emul sions and solid in-liquid dispersions. This last develop114 ment has important consequences in embryology, and in research on cancer. Bob is also a member of the Center for Theoretical Biology. JOHN HOWELL'S research is directed toward many important problems in the environmental area. He is currently performing theoretical and experimental in vestigations on the effects of wall growth of organisms in biological reactors. Such effects have been shown to be of great significance when scale-up of biological re actions is to be done John is currently performing studies on the use of certain types of biological reactors for the production of single cell protein to be used as an animal feed supplement, and for the treatment of indus trial wastes John is offering a new graduate course in immobilized enzyme technology, and, with the help of Greg Vermeychuk, produced a totally new selection of undergraduate advisement materials. John had served as Master of the Rachel Carson College until recently, when he left the post in order to devote full time to the department. KEN KJSER'S research work shows a strong inter disciplinary orientation. He collaborates with members of the Civil and Mechanical departments in the use of their unique rotating models of Lakes Erie and Ontario to characterize the spread of material and thermal pol lutants in these bodies of water. With members of Mechanical Engineering and the medical School he seeks to experimentally determine velocity profiles in the aortae of living dogs. This work will provide information neces sary for the design of better artificial heart valves for human patients. Ken is also conducting experimental work on mixing in turbulent jets. HARMON RA Y'S interests in process modelling, optim ization and control have led him into many diverse fields. He has developed rigorous quantitative descriptions for a number of polymerization systems including copoly merization and heterogenous polymerization reactors. Another major area of interest has been the modelling and optimization of catalytic reactors experiencing cat alyst deactivation and he has developed several efficient optimization algorithms for treating these problems. More recently, Harmon has collaborated with JULIAN SZEKELY to apply modern optimization and control techniques to the problems of the steel industry In order to acquaint the metals processing industry with these ideas, Harmon and Julian have (for the past 3 years) put on a 3-day intensive course entitled "Optimization in Process Metallurgy" which has been well attended by industrial people and professors alike. Harmon and Julian's interest in Optimization, as applied to a number of fields, have led to their recently published monograph entitled "Process Optimization" (Wiley 1973) Harmon has also been active in the field of process dynamics, estimation and control and has contributed papers in a number of areas. These include the control of systems having time delays in the state, control, or measuring device, as well as the dynamic behavior of chemical re actors Harmon's research efforts in process control were recognized in 1969 when he was presented the Donald P. Eckman Award of the American Automatic Control Council. CHEMICAL ENGINEERING EDUCATION

PAGE 13

JULIAN SZEKELY, Director of the Center for Proce ss Metallurgy is active both within the field of Chemical Engineering and Process Metallurgy. He is one of the pioneers o f the application of chemical en gineering techniques to metals processing operations. The co-author of two texts, Rate Phenomena in Process Metallurgy (with N. Themelis) and Process Op timization with Harmon Ray, he has also edited two volumes, Blast Furnace Technology and The Steel In dustry and the Environment. Julian's research ranges from bubble dynamics, turbu lent flow in solidification to gas-solid and solid-solid re actions, and scrap-melting kinetic s Julian publishe s ex tensively in both the c hemical engineering and the metallurgy literature and his work has been recognized by the "Junior Moulton Medal" (British Institution of Chemical Engineers, 1964), the D Sc (Eng) degree (Uni versity of London, 1972), The extractive Metallurgy Di vision (A I.M E.) Science Award (1973) and the Mathew son Gold Medal (A I.M.E ) also in 1973. Laboratory i n the cente r for Process Metallurgy GREG VERMEYCHUK is extending his work on suboptimal feedback control of systems described by partial differential equations. He is developing new com putational algorithms and applying them to models of tubular re actors with the goal of providing more effec tive and reliable software packages for direct digital control installations. It is expected that this work will extend the range of direct digital control to include more complex syste ms of practical importanc e Since joining the department in September, 1971, Greg has started to branch into othe r research areas. He is collaborating with Bill Gill on a combined theoreti cal and experimental study of the use of specially de signed membranes to improve reverse osmosis systems for desalination of water and other applications. Greg will work with Bill in the study of mixing and dispersion in open channel flows. Thi s work will have great im portance in assessing the downstream effects of concen trated sources of pollution, such as industrial discharges. Greg has also developed a new sophomore-level intro ducto ry course in chemical engineering. SUMMER 1973 TOM WEBER has developed a number of models to describe the behavior of adsorption beds. For gas-solid systems, one model accounts for the coupling of the heat transfer and mass transfer effects. This model was suc cessfully tested using a gas mixture of ethane and helium with activated oorbon. More recently, he has turned his attention to liquid-solid systems because of their potential importance in waste water treatment. Both pore-and solid-diffusion models are being explored, as well as the possible effects of axial dispersion. Tom has collaborated with Ken Kiser in a recent study of heat transfer in pulsed laminar flow. Tom is also interested in process dynamics and control. He is carrying on some work on multivariable processes with interactions. As an outgrowth of his teaching in t e rests in control, he has written an undergraduate text book, An Introduction to Process Dynamics and Contr o l, which will be publi s hed by Wiley-Interscience in June. Tom also coordinates credit-free technical courses and programs in the Division of Continuing Education Last, but by no means least, comes our present Acting Chairman, SOL WELLER. Far from new to administra tive matters, Sol has served as Acting Chairman before, as well as having held research management posts in industry before joining the Buffalo faculty in 1965. Sol's study of the supported metal and transition metal oxide catalysts has shown that the special chemical properties of surface ions can help to exp lain their catalytic behavior and their tendency to sinter. He is using alumina-deficient mordenit e to develop a simple picture for the catalytic action of zeolites. And he is applying the Frank-Kamenetskii theory of ignition and quenching at the surface of catalytic wires as a tool to optimize activation techniques for metals. As chairman of a U.N committee, he is active in establishing inter nat io nal standard te st method s for catalysts. Finally, as a member of the Center for Theoretical Biology at Buffalo, he is involved in planning Viking experiments to search for the existence of life on Mars. THE UNDERGRA DU ATE PROGRA M The undergraduate program in chemical en gineering of Buffalo has many unusual features in addition to the rather standard offerings which typify such programs. Within a University-wide framework of thirty-two courses of four credit hours each as a requirement for the Baccalaur eate degree, we have designed our program to afford each student the maximum flexibility in tailoring a program which suits his or her indi vidual needs. In addition to standard lower-divi sion requirements of mathematics, chemistry, and physics, ther~ are required faculty wide courses in the principal engineering sciences. The courses in materials and engineering thermodynamics are often taught by members of our department. The courses in thermodynamics are worthy of note, since the Department of Chemistry accepts these 115

PAGE 14

courses as sufficient preparation for the second course of a two-course sequence in physical chem istry. The normal requirement of the first course is waived for ChE students As soon as they are identified, departmental majors are assigned faculty advisors who help the student make the most out of his or her elec tive courses. Since ChE undergraduates often enter graduate or professional programs in man agement, law, medicine, and other diverse fields, the needs of different students vary widely. Certain unique features of our undergraduate program include the two-semester senior level course sequence entitled Applied Chemical Engi neering, or simply, "ACE." In the ACE sequence, students are exposed to detailed treatments of ChE unit operations from a theoretical point of view, coupled with a series of small design proj ects. With modifications, over the years, this course has been quite successful, especially with the more practically oriented students. Since the course requires intensive preparation, it is usually team-taught by two professors. Undergraduates interested in environmental problems have the opportunity to enroll in the Rachel Carson College, a comprehensive living learning unit specializing in technological / en vironmental studies. The students provide valuable feedback on the degree of success of our teaching efforts in evaluations conducted each semester by the Office of the Provost. In such a climate, dedication to teaching obviously flourishes. We have had some success in encouraging women to enter the profession. Of our 1973 senior class of twenty there are three women. THE GRADUATE PROGRAM The department offers courses of study lead ing to both the M.S. and Ph.D. degrees in Chemi cal Engineering. Of the 50 students in residence at this time, 20 are formally pursuing Ph.D. re116 Weller and Howell at informal faculty gathering. Scanning Electron Microscope. search. Up to June of 1972, 16 Ph.D. and 55 M.S. degrees have been awarded. Of the Ph.D.'s, 6 ~ave obtained university teaching positions, both rn the U.S. and abroad. The department expects to award 17 M.S. and Ph.D. degrees in the 197273 academic year. Graduate research is very active, as detailed in the section on the activities of the staff. To speak in general terms, however, our graduate program offers definite strengths in process metallurgy, materials (notably polymers) and environmental studies as well as the more com mon aspects of chemical engineering. These strengths are expected to be developed further when the department moves to the new North Campus in 1976-77. Graduate course offerings are many and varied Students are encouraged to take courses outside the department in order to augment their research interests and to broaden their back ground. IN SUMMARY From all that has been presented above, and from observation of the day-to-day workings of our faculty and students, one may characterize the department at Buffalo as young, and prepar ing to enter a phase of growth. The addition of Drs. Gill, Ray, and Vermey ~huk, all in the past two and one-half years, has increased the scope of departmental research. For September 1973, Professor Eli Ruckenstein will come to Buffalo as Faculty Professor of En gineering and Applied Sciences. Professor Ruck enstein is already interacting on research prob lems with three members of the department and will be offering courses within the departme~t CHEMICAL ENGINEERING EDUCATION

PAGE 15

[ijn a classroom INTRODUCTION TO CHE ANALYSIS T. W. F. RUSSELL and M. M. DENN U nfoe rsit y of .Delewar e Newark, DE 19711 The transition of chemical engineering educa tion during the past two decades from an empiri cally based, design oriented curriculum to the so called "engineering science" approach has been neither smooth nor totally successful. Today's curricula have been justifiably criticized for fail ing to teach applications of principles, and the new trend appears to be a "return to design." A principle-based curriculum can be oriented to wards practical engineering application and pro vide the necessary blending of design and engi neering science. The resolution lies in imagina tive use of the introductory course in chemical engineering, usually taught at the sophomore level. The sophomore course in Industrial Stoichio metry has changed little during the era of major modification of upper-class undergraduate and graduate curricula. Though "modernized" at times by introduction of the digital computer to assist in the solution of large problems, the course content remains by-an-large the solution of steady state mass and energy balances for existing pro cesses. Skills are haphazardly developed through many example problems and little attention is paid to the development of a consistent logical approach to engineering problem solution. Recent developments which have greatly improved and expanded high school and university freshman courses are ignored. The student's mathematical skills are not adequately reinforced with practice in engineering problems and almost no attention is paid to his improved abilities in elementary calculus and basic chemistry. In an attempt to "simplify" problems for the sophomore level many concepts, particularly in basic thermodynamics, are introduced incorrectly a nd a re-learning must take place in the courses which follow. Con sid er ations of d e sig n ar e n e ve r in c luded because the c o nc ept of a ra te is us u ally not introduced. The type of problem considered has little to do with the creative aspects of traditional chemical SUMMER 1973 engineering practice or the extension of chemical engineering skills to a broader class of problems. : The inadequacy of the traditional sophomore course is compounded by the lack of continuity between it and the "engineering science" courses which immediately follow: There is a difference in approach, type of problem, and analytical level. The transition is a difficult one for many students, and in 1965 the Chemical Engineering Depart ment at Delaware initiated a program to study, modify, and if necessary, reorganize the intro ductory course in the curriculum. This study has resulted in our present "Introduction to Chemical Engineering Analysis" course, which meets the following three objectives: To reinforc e, ampli f y, and appl y in an e nginee r ing e nvironment th e mat e rial cov e r e d in basic chemi s tr y ph y sic s and mathemati cs To develop the basic s k ill s need e d a s a s ound founda tion fo r uppe r l ev el cou r ses. To d e velop an early appreciation for design by involv in g the student in s imple but s i g nificant chemical e n g in ee rin g d es i g n problems. Because of the considerable discussion in the profession about the proper direction for under graduate education it seems to us that it is useful to recount our approach and the evolution of the course and our thinking. We do this because what seemed to us and many colleagues to be obvious remedies for the deficiencies noted above were not successful at all, and the final course outline differs considerably in content and tone from o u r first attempts The course in its present form is a result of some five years experience teaching the subject to sophomore students in both the regu lar and extension programs. Some portions of the material have also been used with engineers and chemists who participated in AIChE con tinuing education courses at both the national (Today Series) and local levels. For three years we taught the course together at the same hour each with a section of about twenty-five students The material was coordinated on a lecture to lecture basis and its impact on students was evaluated after each lecture and again after each major topic had been covered. Substantial stu117

PAGE 16

T. W. Fraser Russell received the Bachelors and Masters Degr ees at the University of Alberta. He worked as a research engineer for the Research Council of Alberta and as a design engineer at Union Carbide Canada be fore 1eceiving the PhD ('64) from Delaware. He is on leave for 1972-73 at ETH Zurich Professor Russell re ceived a University of Delaware Excellence in Teaching A ward in 1968. His primary research interest is on two phase system analysis and design, and he has a book in progress in the area. (left) Morton M Denn received the Bachelors Degree at Prince ton University and the PhD (64) at Minnesota. He has been at the University of Delaware since 1964 and was a Guggenheim Fellow in 1971-72. Professor Denn's major research areas are the fluid mechanics and rhe olo gy of polymeric liquids and optimization and optimal control. dent feedback has been received, and several undergraduates and graduate students have worked with us for extended periods in evalua tion and revision. This method of teaching has allowed us to experiment with various ways of organizing and presenting the material, and we feel that we have found a very effective way to introduce students to chemical engineering. In the first year, we taught a slightly modified industrial stoichiometry course, followed by an applied mathematics course which concentrated on solutions of various types of differential equa tions encountered in chemical engineering. This latter course replaced .the more classical course in differential equations taught by the mathema tics department. It quickly became apparent that the major problem the student faced was develop ing the equations that described a particular sit uation. Since he did not feel adequately trained in this skill, there was a strong tendency to sep arate the mathematical description and its be havior from the situation which it described. This had two equally undesirable effects. Some students concentrated on the mathematical mani pulation and thought little about the relationship 118 Today's curricula have been justifiably criticized for failing to teach applications of principles and the new trend appears to be a "return to design." to the physical situation, while others became confused as to the role of mathematics and tended to dismiss the material as being an academic exercise unrelated to physical reality. (This is not unlike what has happened outside the Uni versity in professional practice. It has been our experience in continuing education activities that the greatest number of engineers who profess a need for "more mathematics" are really in need of a better understanding of model development) In an attempt to overcome these serious prob lems and also to revise what we considered to be inadequate or incorrect presentation in the stan dard stoichiometry course, we decided to restruc ture both courses and to concentrate on develop ing the skills which would enable the student to see clearly the relationship between mathematical description and physical reality. We attempted to meet this goal the first time we taught the integrated course by developing mathematical models for a series of increasingly complex physi cal situations. This "case study" approach was moderately successful and, although it did not Constitutive relation Physical situation Selection of fundamental dependent variables Se le ction of characterizing dependent variables Selection of control volume Application of conservation principles Basic model equations No Yes Mathematical mode l Fig 1. Model development for any physical situation. CHEMICAL ENGINEERING EDUCATION

PAGE 17

meet our goal of developing a systematic pro cedure for model development, the students did develop some facility for seeing the proper role of mathematics in the study of engineering The logic procedure outlined in Fig. 1 was introduced on the third try at the course We emphasized this time the need for experimental verification of constitutive assumptions, as dis tinct from the application of conservation prin ciples. This e m p hasis on the role of experiment in engineering is, paradoxically, the key to a student's understanding of the role of mathe matics. At this time we oriented the course to wards liquid phase reactor performance and con centrated on a complete study through design using a single conservation principle (mass) before introducing a second. We also found as we progressed through the third year that it was necessary to drop some of the mathematical skills we had stressed so that the more important as pects of analysis could be properly covered We eliminated material on differential equations with variable coefficients and reduced our discussion of the Laplace transform An initial review of the third year's classroom experience produced a course outline similar to what now exists and pointed out a need for still more emphasis on the experimental aspects of engineering and the use of the mathematical de scriptions for simple design. Thus we decided once more to reduce the mathematical content, result ing in total elimination of the Laplace transform. ( Students with the need for such mathematical skills learn them in the senior Process Dynamics and Control course). We concentrated in our fourth year on better organization of the material with respect to the model development step in analysis and we reor ganized, using more experimental data, the methods by which constitutive relationships were employed. Our goal was to make sure that all the relevant material normally covered in the stoichio metry course was introduced in a rational and c onsistent manner. Since then the emphasis has been mostly on polishing and minor changes. The sophomore courses, ChE. 230 and 231, are taught for two shortened semesters, totaling twenty-seven weeks. The relationship of these sophomore courses with other ChE courses at the University of Delaware is shown in Table 1. Since our students are not required to take a separate course in differential equations, but rather study the subject as part of the chemical engineering SUMMER 1973 Freshman TABLE l Bas i c Departmental Course St r ucture Introduction to the art and science of engineering EG 1 25 ( Introduction to Eng i neeri n g) EG 130 (Introduction to Engineering Research) Aquisition of the basic engineering skill of Analysis -Hm 1 to proceed from experiment to design ChE 230 231 ( I ntroduction to Chemical Engineering Ana l ysis) The basic phenom e na are s tu d i ed from an engineer i ng v iew p oi nt Applied Physical App li ed Chem i ca l f::ngineering Sciences Enginee r ing Scienc e s ChE 341 ChC 3 2 5 332 (Fluid Mechanics) (The r modyna m ics ChE 34 2 and Kinet i cs ) (Heat and Mass Transfer} ChC 34 5 (Chemical Engineering Lab) Skills are integrated by studying comple x engineering proble~s in c l ass in the l abo ratory antl by individual t h esis ChE 432 (Chemical P r ocess Ana l ysis Design ) ChE 443 (Transfer Operations) ChE 445 (Chemical Engineering Laboratory) ChE 473 474 (Senior Thesis) ChE 401,466 etc. (Electives in Control Pollution Abatement Polymer Processing Chemical Economics etc .) analysis course, a one-semester course employing a major fraction of our outline is possible. Em phasis is on the analysis of liquid phase systems, for this enables the student to treat meaningful design problems during his first semester of engi neering study. He takes this course concurrently with the final semester of calculus and two semes ters of physical chemistry. The topics covered follow our book, I n t roduction to Chemical Engi neering Analysis, Wiley, New York, 1972. INTROD UCT ION We start with a brief description of three chemical engineering problems, where the emphasis is on "putti ng together the pieces." We discuss a typical chemical process, the manufacture of ethy lene glycol; the operation of an artificial kidney; and the design of a bio oxidation reactor for sewage treatment This int ro duces the idea of reactor, separation process, etc. We then turn to a detailed study of the analysis process, which we define as follows: 1) Description of a physical situation in mathematical symbo ls. 119

PAGE 18

Student response has been excellent ... 2) Manipulation of the mathematical model to deter mine expec ted behavior of the physical situation. 3) Compariso n of the model with th e true physical s itu at ion. 4) Carefu l study of the limitations of the mathema tical model. 5) Use of the model for equipment design and prediction of performance. ANALYSIS. Several days are spent discussing the basic c on cepts involved in analysis and the total analysis proce ss is described by means of the simple example of an empty in g tank. The model development step is illustrated using real data to develop a re lation s hip between outflow and height of liquid (the orifice equation). Next the laws of conserva tion of mas s, energy, a nd momentum applied to a well-rlefined control volume are shown to be the basic source from w hich mathematical descriptions are de r ived A careful distinction is made between general conservation principles, universally applicable, and spe cific co n stitutive relations applicable only to certain situations. The necessity of experimental data for the development of constitutive relationships is stressed and dimensional analysis is introduced as one means for planning this needed exper imental program A series of logical procedures is developed to show the student how mathematical descriptions for a physical situation are developed. The ultimate logic is shown in Figure 1. NON-REACTING LIQUID SYSTEMS Model develop ment for well-mixed tank-type liquid systems in transient an d s teady state isothermal operation is illusrated in detail, with an experime ntal check of the perfect mixing assumption and a crit i c al appraisal of the role of the de n sity co n ce ntration constitutive equation. The purpose is to give th e student p ractic e in the mod e l development step of analysis with s impl e problems, so that he can clearl y see the relationship between the mathematical description and the physical situation The simpler aspect s of basic calculus are employed to determine model be havior and, as a seco ndary aim, p r actice with manipula tion of the mathematical description to determine model behavior is s tre sse d As one example to meet this latter aim we exploit the draining tank problem and design a s impl e feed back controller. This also shows the student s om et hing about the design aspect of analysis. REA CT ION RATE. Reacting, well-stirred single phase li quid systems are studied next The reaction rate arises naturally in the c omponent mass balance and reasonable phenomenological forms are deduced. Emphasis is on the use of batch reactor data to determine the validity of constitut iv e assumptions for the 1 ,a te and to find the values of the parameters. Real batch data are used in all cases. REACTOR DESIGN. The s teady state model equations for a well-sti1Ted co ntinuous flow reactor are used for two desig n problems. In the first, a r eactor is sized to meet production requireme nts for a single, irreversible first order 1eaction, taking capital and operating costs and 120 depreciation of the reactor and separation unit into account. (The economics are obviously simplified). The other is the problem of sizing a reactor to obtain a required distribution of mono ,di -, and trie thylene glycol (a process introduced e arlier). The sophomores take this material nicely in stride and take pride in their ability to u se the mathemati ca l descriptions. We intro duce the plug flow tubula r reactor here for comparison. MASS TRANSFER RATE. Two -ph a se, well-stirred sys tems are studied to introduc e the concept of mass trans fer and to further develop modeling sk ill s Th e rate of inter-phase ma ss tran sfe r aris es naturally in the com ponent balances and, like the reaction rate, reasonable phenomenological forms are deduced. Batch data ar e used to study the approach to equilibrium. For a co ntinuous flow proc ess the equilibrium stage is s hown to be a good approximation for typical mass transfer data. Stage efficiency and reaction i n a two-phase sys t em are briefly examined STAGED PROCESSES. Multistage solvent extraction is studied analytically and graphically (McCabe-Thiele). Calculations are done for minimum solvent requirements and numbers of ideal stages. Th e triangula r diagram is used for single stage calculations. The material nicely illustrate s the use of graphical te c hniques in the model b e havior step of analy s i s. This is roughly the e nd of our first semester, together with some math e matical topi cs as needed, including least squares fitting to data. The student deals routi n e ly with dynamical s ituations a s well as the steady sta t e but he never requires mathematical concepts not already used in his calculus course. The interplay b etween laboratory experiment (measuring reaction rates, mass t ra nsfer c efficients, equilibrium constants, etc.), mathematical modeling, and engineering design calculations is brou gh t home This works becaus e ther e i s s imply no easier practical problem in chemical engineering than the siziU:g of a liquid pha se reacto r wi th uncompli cated chemistry. The student is motivated to go on to e n gi ne eri n g scie nce courses and learn, for example, why a mass transfer coefficient is of a given order, o r how to estimate one in the absence of an experiment. Most important, he has l earned a sys tematic approach to solving problems. At this point we turn to non-isothe r mal systems. In s ome curricula it might be desirable in a one semester c ourse to skip s ome or all of the material on mass trans fer proc esses and include some of the non-isothe rm al material. Emphasi s is on the operational definition of thermodynamic qua ntiti es and to avoid the complicatio n of compressibility, liquid phase syste m s are stud ied first. CONSERVATION OF ENERGY. Internal energy is in troduced and the principle of conservation of e n ergy applied to a flowing system The square root orific e equa tion is derived using the energy balanc e. Internal energy and enthalpy are related to temperature by defining the heat capacity. Pa r tial molar enthalpy is defined and u se d to define the heat of solution and the heat capacity of a mixture Students are prepared to deal with partial molar quantities at thi s level because it comes sufficie ntly s oon after seeing partial differentiation in the calculus course. CHEMICAL ENGINEERING EDUCATION

PAGE 19

Th e s t ud ent i s continu a lly r e f e r r e d back to r elevant section s of his c alculus and chemist ry te x ts de v elop i ng i n his eyes, a logical c ontinuity between his basic s ecience courses and creat i ve engineering Phy sic al che m istry l abo r ato ry exp e r im e nts ar e often discussed i n our classroom MIXING AND HEAT TRANSFER. In parallel with the i sothermal system development, we model non-reacting liquid sys tems. Consideration of temperature effects in batch mixing i s followed by construction of the enthalpy concentration diagram and grap hical solution of the same problems. This is then repeated for steady state con tinu o us mixing The analysis of mixing i s done rigorously, usin g partial molar e nthalpies for otherwise the student learn s incorr ec t procedures wh ich ensure the wrong answer when w o rki n g with multi-phase sys tems. Heat transfer between adjacent chambers leads naturally to the rate of heat transfer and definition of the heat trans fer coefficient Area and flow rate calculations are carried out for cooling a tank by a jacket and a coil. REACTING LIQUIDS. Reacting liquid systems are dealt with after the student has seen how partial molar quanti ties are u se d in the si mple mixing situation. The heat of reaction is defined in terms of th e partial molar enthalpy and the batch reactor eq uations derived which demon strate how to measure it. Calculation of the h ea t of reaction from tabular data is di sc u ssed The Arrhenius temperature dependence of reaction rate is demonstrated and the transient adiabati c batch react or equations for a single reaction are integ ra ted using numerical quadrature (This s till requires only the calculus course as prepara tion .) The energy balance for a continuous flow stirred reactor is derived. A numerical so lution of the steady state i s obtained, and the qualitative behavior of the non iso th ermal reactor is discussed using the Van Heerden slope argument and phase plane construction via the method of isoclines. The non-i sothe rmal tubular reactor is touched upon very briefly. By this point the student is becoming quite skilled in making his mathematical skills work for him to understand physical problems TRANSIENT REACTOR BEHAVIOR. We include this mate r ial as the practical application for linear differential equations, which are included in the course. The section can be omitted without seri ous los s The Teactor equa tion s are linearized in the n eig hborhood of the steady state to obtain a linear seco nd order system with constant coefficients. Applications are to th e sta bility of the steady s tat e, response of a stable system to a feed disturbance, and proportional feedback control by coolant flow rate adjustments. Student s have no trouble with the notion of lineari za tion. They have seen a number of examples in which the physical problem is severe ly limited in orde r to obtain a tractable mathematical model, and they recognize the virtue and limitation of such a trade-off. GAS SYSTEMS To show that analysis skills can be readily extended we d ea l with gas systems as a final topic. Non-reacting and reacting batch systems are re-examined w ith the compressibility t erm reta ined in th e energy e quation. Constitutive equations are introduced for the ideal gas and several non-ideal gases and the compres sibility chart and mixing rules are introduced. SUMMER 1973 MATHEMATICS At appropriate times we cover numeri cal methods for solving al gebra ic equations, and, towards the end of the course, analytical solution of linear, non homog e neous differential eq uations with constant co e fficients and elementary numerical solution of nonlinear differential equations. Student response to the course has been excel lent. We feel, with some pride, that this is at least in part a reflection of the course content and organization, particularly chemical engineering courses seem to the student to be a natural out growth of the analysis course. There is another factor, however, which helps considerab l y. The student is continually ref erred back to re l evant sections of his calculus and chemistry texts, de veloping, in his eyes, a logical continu i ty between his basic science courses and creative engineering Physical chemistry laboratory experiments are often discussed in our classroom. This blending is in stark contrast to the nearly total discontinu ity which existed under the old program. Colleagues unfamiliar with the details and student performance often express concern over the level of material and wonder whether sopho mores can really handle it. Our emphat i c "yes" supported by formal AIChE student chapter and Student Government Association evaluations, is most easily justified by a related fact. Last year we introduced a course for non-majors based on our first semester course. We will discuss that course i n detail at another time, but it is qu it e similar i n content and level to the first semester course for chemical engineering majors. We have had participation from students to biology, chem istry, economics, home economics, and seco nd ary ed u catio n among others, some of whom have studied no chemistry. Registration went from eight in the first year to thirty-two in the second, and the course is recommended now by the chem istry department for its undergraduate majors. The st u dents rated the course 4.7 out of a possib l e 5.0 in the SGA evaluation. It is clear from the performance of the non engineers that our engi neering procedures for problem solving are appre ciated by a much larger portion of the student body than we originally anticipated When the concepts can be grasped by non-majors, it is evi dent that the material belongs at the sophomore level in a Chemical Engineering curriculum. 121

PAGE 20

THE UNDERGRADUATE CHE LABORATORY* H. S. FOGLER1, A. J. PERNA2, and F. H. SHAIR 3 The laboratory workshop format consisted of a number of speakers each discussing a particu lar aspect of a laboratory. The papers presented can be classified in four categories: 1) the phi losophy and objectives of the laboratory, 2) com puter aided laboratory instruction, 3) types of laboratories and experiments, and 4) different approaches and instructional techniques. To assess the attitudes of laboratory instruction along with current and future trends in each of the above categories, a 10-page questionnaire was prepared and mailed to over 50 chemical enge neering departments (primarily those who had faculty members registered for this workshop) in the U.S. and Canada and to a significant number of industrial contacts. I. PHILOSOPHY AND OBJECTIVES The major results of the survey were dis cussed in the first paper of the session by H. S. Fogler. The consensus indicated that the most im portant goals of the laboratory were to Demonstrate or reinforce principles or phenomena discussed in class, Giv e th e s tudents practice in planning and interacting w ith the experiment, Develop the students' inter es t in experimentation, Develop a p r oficiency in technical report writing and Expose the student to open-ended experiments of a rese arch or design nature. Information on the philosophies of the laboratory at various universities along with ideas about experiments which impart a sense of learning to the student and leave him with a sense of accom plishment were also summarized in this paper. The results of one question, when averaged, showed the following allocation of the student's time currently spent on a given experiment. 1. The Univer si ty of Michigan, Ann Arbor, MI 48104. 2. N e wark College of Engineering, Newark NJ 07102. 3 California Institut e of Technology Pasadena, CA 91109. 122 15 % of the time s hould be spent in preparation for the experiment 30 % should be used for setting up and carrying out the experiment 25 % s hould be spent on computation and analysis for the rnw data 30 % should be used for writing the report on the ex periment. Many felt that too little time was currently being spent on giving the students practice at planning and interacting with the experiment to learn the process of experimentation, i.e., the technical and managerial skills required to carry out effective experiments. In the future, it is hoped that most laboratories will provide the student with the opportunity to plan meaningful experiments and experimental programs in which the outcome is not known or is uncertain and in which one must allow for contingencies. Also discussed in the first paper were a few techniques used at The University of Michigan to complement the standard laboratory exercises in order to increase the student's capabilities for planning effective experiments. In particular, the use of guided design instruction in the synthesis of experimental projects at the sophomore level has proven quite effective. Here, a group of 3-4 students ( 1) define and develop the need for an experiment which they would like to perform, (2) state the constraints on the experimental pro gram (3) determine the key or critical measure ments to be made, ( 4) suggest methods of pro cessing and analyzing the data, (5) support alter nate approaches to various segments of the proj ect, (6) suggest possible outcomes and means of evaluating the effectiveness of the programs. Each group receives feedback from the instruc tor at various stages of the planning and then gives an oral presentation and defense to the other groups at the end of the semester. Methods of implementing the open-ended approach laboratory were presented by R. Clift and 0. M. Fuller. They described a ChE Labora tory course at McGill, in which a special format ''' Report on the Under gr aduate Laboratories Workshop at the ASEE Summer School in Boulder, CO 1972 CHEMICAL ENGINEERING EDUCATION

PAGE 21

Fogler Perna called the Evolutionary Laboratory has been de veloped in order to place emphasis on the process of experimentation itself. The distinctive features are s pecialization of the staff for optimal use of teaching personnel, and the conference period for rapid feedback and evaluation. Work on each unit of apparatus is directed by an experiment controller (EC) who acts both as technical expert and teacher. The EC has suffi cient freedom in planning so that he may, for example, direct a lo g ically connected sequence of experiments rather than repetitive exercises Fol lowing each laborato ry exercise, the students have a conference wi th the EC which cons ists of an oral report, a teaching sess ion, and an occasion for feedback on instructions and apparatus. The conferences permit flexible plannin g and evolu tionary changes in the exercises. The teaching of experimentation requires, among other things, a description of the proc ess in terms of observable behaviors and a methodolog y for planning ex periments For this purpose, the McGill program offers a desc r iption in terms of instructional ob jectives and an extension of PERT for planning. In addition to comments on the laboratory received from industry on the questionnaire, in formation was gathered and presented by Drs. C. C. Zimmerman and D. N. Burdge of Marathon Oil Company w ho view the laboratory as a tool to increase the student's problem so l vi n g capabili ties through expe rimen tation. They re inforced earlier presentations suggesting that greater emphasis be given in the laborator y to problem definition and anal ysis and to experimental plan ning. This is to help insure that the student or employee may learn to decide wh ich measure ments will be meaningful and not to carry out unnecessar y experiments whose resu lt s could have SUMMER 1973 Shair been obtained by other means, such as a combina tion of reasoning and calculation. They encour aged greater development of the student com munication skills primarily through report writ ing but also through oral reports to the instruc tor. It is interesting to note that while only 50 % of the universities returning the questionnaire stated that report writing was a major objective of the laboratory, every industrial reply suggested that improvement in the students report writing should receive major attention. II. TYPES OF LABO RA TORIES AND EXPERIMENTS F. H. Shair reported the survey results con cerning the attitudes expressed by ChE faculties towards the laboratories in chemistry and physics which are required by students who enroll in the ChE curriculum. Generally the ChE faculty were satisfied, but certainly not enthusiastic about the chemistry laboratories. On the other hand, the ChE faculty generally expressed moderate dissat isfaction with the physics laboratories. Over half of the persons answering the q uestionnaire stated that they believed their required physics labora tories to be of little value in aiding their students in developing important laboratory techniques, in helping their students to analyze experimental error and uncertainty, in helping their students develop report writing, in helping their students develop oral presentations, and in helping their students formulate an experimental path aimed at obtaining desired answers with the least effort. The merits of the undergraduate laboratories de veloped by E. C. Stone and D. W. Skelton at Caltech discussed in some detail. Professor Shair also described a ChE inte grated concepts and laboratory course which has been given during the last five years at Caltech. 123

PAGE 22

The fundament a l s of ChE a r e emphasized alon g with both oral and written presentations. The laboratory experience involves open-ended proj ects which are also of interest to someone outside of Caltech. Recent experimental topics involved the internal combustion engine, the melting of icebergs, the spreading of oil slicks, the dec a y of ozone within buildings, transport acro s s pul monary membranes, and transport across artifi cial kidney membranes. Students participate in the planning as well as in the conducting of ex periments. Several projects are in some stage of being published in the open literature. Exams are given in the form of scenarios. The most im portant aspect for course update and improve ment involves the r ecycle of the top 10 % of the class into teaching assistants du r ing the follo w ing year. Discussed by A. J. Perna were those results of the 10-page questionnaire relating to the Unit Operations Laboratory. A summary of the over thirty schools responding showed that: All had e ith e r c on v entional Unit O p er a tion s Labo r tory or a Transport Laboratory; Labor a tory ex p er i e nc e r an th e g amut from a t hr ee level approa c h ( s ophomo re -juni o rs enio r) to o nl y a senior ye ar ( m a jo r it y) c ou rse; Laboratorie s w ere pr imaril y hardwa re r ath er t han compute r oriented ; In general, laboratory experiments wer e a blend of pilot plant s ize and tran s port s ize; Inte g rated L ab-Th e o ry c our ses we re r a r e w ith only appro x imately 18 % o f th e sc hool s u s in g thi s approach; All schools hav e ex p e rim e nt s d es i g ned to cov e r the a r eas of Heat, Mas s and Mom e ntum T ra n s port in thei r Unit Operation s Laborato r y but s om e s c hool s a l s o hav e inco r porated e x p er im e nt s in kinetics thermo and p r o c e ss control and dynam ic s in th e lab; In g e neral th e lab improvements hav e be e n in th e a r eas of instrum e ntation op e ne nd e d ex p e rim e tation, a nd r e du ce d wo r kload. One important factor which came out of the sur vey was that the laboratory has become an area for exposing the students to concepts not taught in the classroom and that it is an extension of his learning process and not completely integrated with the material presented in theory type courses. R. D. Williams described a one hour chemical reaction engineering laboratory currently being used at The University of Arizona In this labora tory the student is exposed to a number of differ ent types of reactors used in homogeneous liquid 124 Many felt that too little time was spent on giving students practice at planning and interacting with the experiment .. phase reactions, in catalytic heterogeneous re actions and in non-catalytic heterogeneous re actions. A number of methods of data collection, ranging from direct sampling and titration or gas chromatography to direct temperature and pressure measurements, are illustrated in the course along with different methods of data an alysis. The students could use these reactors to carry out reactions whose rate laws have been reported in the literature or to study reactions w hose kinetics have not been reported. An alternative to the weekly laboratory in the form of a three-week intensive course was pre sented by G. B. Williams and J. H. Hand of The University of Michigan. In this course, which is offered at the end of each winter term, the stu dent has essentially an entire day to complete the experiment and write his report. Consequently he is not under the usual pressure to get the experi ment working and finished within as soon a time as possible in order to rapidly go on to other course assignments. In the intensive course there is adequate time to modify and experiment with the equipment, and also time to profit from rou, tine difficulties and breakdowns of the equipment. While the faculty and students are equally en thusiastic about conducting the course in this manner, the only two serious drawbacks appear to be centered around finding housing for the students fo r only three weeks after the end of the term and the lab's interference with some summer jobs and summer school. R. M. Hubbard presented a pilot plant oriented experiment which students undertake as a final experiment in the ChE laboratory at the Uni versity of Virginia. The experiment is multi purpose and forces students to work as a team to take data make material balances on a process as soon as data are obtained, and to experience a continuous operation such as might be encoun tered later in industry. A small operating chemi cal plant produces hydrogen and carbon dioxide from the catalytic decomposition of a vaporized methanol-water mixture at 300 C and atmos pheric pressure. The students operate the plant in shifts for most of a normal day and acquire enough data to carry out at least two complete material balances per shift CHEMICAL ENGINEERING EDUCATION

PAGE 23

Ill. COMPUTER AIDED LABORATORY INSTRUCTION D. E. Seborg described the computer-aided student laboratory which he and D. G. Fisher have developed during the last five years at the University of Alberta. The computing facility in cludes an EAI 590 hybrid computing system plus an IBM 1800 digital computer which oper ates in a multi-programmed, time-shared mode and allows several research workers and student laboratory groups to have simultaneous, open shop access to the real time and background com puting facilities. Typical real-time applications include control of pilot-plant processes, automa tion of analytical instruments, and student oriented experiments designed to demonstrate particular hardware and / or software features It was stressed that when properly used, the computer can take over the time consuming routine tasks and let the student concentrate on the important, fundamental concepts of the ex periment. R. A. Schmitz described the on-line computing facility for undergraduate instruction which he has developed during the last three years at the University of Illinois. The system utilizes a time sharing IBM 1800 computer in conjunction with an undergraduate process dynamics and control laboratory. The apparatus connected to the com puter constitute simple closed-loop systems for studies of mathematical modeling and direct digi tal control. Students using the system must write a FORTRAN program to handle the collection of data, the sending of feedback signals and any calculations involved in the data processing. The system also provides for the connection of an EAI 580 analog computer to the digital machine so that the computer control of complex systems may be simulated. The facility is being employed in a required undergraduate course on process dynamics and control and in an undergraduate projects course. IV. DIFFERENT APPROACHES AND INSTRUCTIONAL TECHNIQUES An integrated theory-laboratory course ap proach was described by R. R. Furgason of the University of Idaho. The approach is to block out from four to six hours per week for a sched uled three credit course and have the class meet in a lecture mode for several weeks followed by one or two weeks of class devoted to laboratory experimentation. This allows the laboratory to be utilized whenever appropriate rather than on SUMMER 1973 An integrated theory-laboratory course was described ... This allows the laboratory to be utilized when appropriate rather than a fixed schedule. some fixed schedule. The main advantage is the excellent coordination between theoretical and ex perimental phases of the class with the laboratory neither leading or lagging the course. The dis advantage is primarily logistical in terms of class, manpower, and scheduling. The integrated laboratory-lecture approach is being carried out on a much larger scale at Wor cester Polytechnic Institute, where it encom passes the entire curriculum. Professor I. Zwiebel discussed the WPI project approach in which courses are viewed as elective tools to build the foundations for completing the students two major projects, which are the primary require ments for graduation along with a competency examination and a humanities minor. Many proj ects are inter-disciplinary in nature and require a team of students ( e.g., a civil engineering chemical engineering, etc.) each with his particu lar responsibility, working together to obtain a solution. Special projects, sponsored by a Sloan Foundation grant, run through about 1 1 / 3 cal endar years during which time the student's time is divided equally along the following four seg ments of the project: preparing a proposal of the project plans executing the plans, analyzing the results, and preparing written and oral re ports. The WPI project approach offers a sig..c nificant alternative to the conventional engineer ing programs. J. 0. Maloney and G. M. Kortman of the Uni versity of Kansas presented material on two in structional laboratory units. The first was con cerned with an experiment in unsteady-state cool ing, while the second unit treated the determina tion of binary vapor-liquid equilibrium data using an Othmer still. Especially developed for inexperienced instructors, each unit contains sufficient material that the instructor, after read ing it and doing the experiment once or twice, would have adequate control of the experiment and would be able to estimate the validity of student results. Each unit provides the following information: equipment description, experimental procedure, extensive data, calculations, computer programs, error analysis, and suggestions for modification of the experiment to achieve variety. (Continued on p. 135) 125

PAGE 24

BERNOULLI'S EQUATION WITH FRICTION NOEL DE NEVERS University of Utah Salt L ake City, UT 84112 This demonstration shows examples of flows in which inertial effects are greater than fric tional effects and the converse These are ex plained in terms of Bernoulli's equation with friction. APPARATUS The apparatus consists of: 1. A one-gallon so lvent can, into which a 1 /4 IPS coupling is so l dered n ear the bottom 2 A one-foot l e n gth of IPS pipe with five OD holes drilled in it on 2" centers. These holes are all aligned on one lin e in the pipe surface, parallel to the pipe axis. Both e nd s of the pipe are threaded. 3. Same as No. 2, except that into each of th e five holes a lon g piece of ~ i OD copper tubing has been slipped and soft-soldered in plac e. 4 A piece of ,'' rod 12" long 5. A 1 /4 11 IPS pipe cap. 6. A s hort length of rubber tubing. 7 One ga llon of water thickened with 1.0 wt % Methocel 4000, estimated viscosity 100 to 150 cp DESCRIPTION OF DEMONSTRATION 1. Th e instructor sets the ca n on the lab bench over a sink, with part No. 3 in serted in the co upling and th e end of No. 3 covered with the cap (No. 5). He shows it to the cla ss describes it to them, and t e lls them he is about to fill the can with water. He asks them to predict which jet from th e pieces of tubing will ri se th e highest. Aft e r taking a poll of the class, he fills the can (using the rubber ho se) The water jet squirts highest from the tube farthest from the can and s ucc ess ively lower from the tubes n earer to the can 2. Th e instructor then removes the cap from the end of the pipe, inserts the rod, replaces the cap, and te ll s th e st udent s that he will again fill the can with water. He a gai n asks wh i ch j e t will go hi g he st and records the res ults of hi s po ll. He then fills th e can with water Thi s time t he water squirts hi ghest from the tube nearest the ca n. 3. Th e instructor removes the rod from the tube and tells the s tudent s that he is about to fill the can with the methocel so lution. Again h e takes an opinion poll on which jet will go highest H e then pours the so l ution into the can The jet nearest the can squirts highest, but none of the jets sq uirts as high as in demonstration No. 2. 126 4. Th e instructor then removes part No. 3, rinses the can, and rep la ces part No. 3 with the pipe which ha s on l y hol es (part No. 2) He tells th e cla ss that he is go in g to fill the can with water and again quizzes them as to which jet will g o highest. After recording the predictions he filh; the can with water. Thi s time there is a humps haped distribution of hei g ht s with the highest in the middle The s treams are very unequal in width, with th e stream near es t the can the thinnest and the far stream the thicke s t. The s treams are not vertical, as before, but l eave the holes at an angle away from the can, with the strea m n earest the can about 10 from the vertical and the stream farthest from the can about 30 from th e vertical. It i s also observed that eac h of the s treams uses only part of the hole to ex it through, and that part is the part farthest from the can. The near ho le issues a stream which fills about one fifth of the hole area ; this fraction g row s to about three fourths at the far hole. 5. Th e instructor exp l ains the foregoing experime ntal results. THEORY For the first three demonstrations with the fluid rising through the small vertical tubes, the flow (and, hence the height to which each jet r ises) depends only on the static pressure at the base of the vertical tubes. The sharp right-angle turn which the fluid makes entering these tubes prevents any of the horizontal momentum of the fluid from being converted into vertical momen tum. To find the pressures at the base of these tubes vve apply Bernoulli s equation: ( p V 2) dW t; + gz + = F p 2 dm (1) Here states 1 and 2 are chosen as shown in Figure 1. FLOW i COPPER i TUBES -CAP c:::::::: :::::] PIPE 3 Figure I CHEMICAL ENGINEERING EDUCATION

PAGE 25

Noel d e Nevers ea rned hi s BSChE at Stanford and hi s PhD at th e Univ ers ity of Michiga n with a year out in b e tw ee n to b e a Fulbright exc han ge st udent at the T ec hni c al In s titute in Karl sr uh e, Germany H e spe nt five ye ar s with what is now Chervon Re searc h and Chevron Oilfi e ld R esea rch, b efore joining th e faculty of the Uni versity of U tah. H e spe nt Academic 1971 72 on leav e, worki n g for the Offi ce of Ai r Pro gT am s of the Environ mental Prote c tion A ge n cy. H e i s th e author of a text book on Fluid Mechanics, and editor of a book of reading s a nd di sc u s sions on Technology a n d Society. From 1 to 2 there is no change of elevation or any pump work done on the system and V 2 is zero; so 2 P2 -Pl Vl --= F (2) p 2 Substitutin g for F from the Fanning friction factor equation (1) and solving, 2 = Pl + l. [1 4f .!,_] (3) p p 2 D Equation 3 indicates that if 4f L / D is less th a n 1, the static pressure at 2 w ill be greater than at 1; and, if 4f L / D is greater than 1, the static pressure at 2 will be less than a t 1. Thus, by adjusting the value of 4f L / D, one can cause the wa ter to squirt highest from eit he r the far thest or nearest tubes. This analysis is not restricted to t he two e nd holes. It can be applied to holes n and (n + l) yielding P P vz [ ] v2 = __!!___ + __!!___ 1 4f .!,_ p p 2 D 2 (4) Here V 11 is always greater than V 11 + 1 ; so, if f = 0, P 11 + 1 is always greater than P 11 Thus, for any two holes the relative jet heights a re determined by the value of (1 4f L / D) between them In experiments run as described above, with the can held full of water so that the flow was at steady state, it was found that, wi th no rod i n the pipe, the flow rate out of the farthest tube was 1000 cc / min; the Reynolds number in the pipe SUMMER 1973 just upstream of it was about 10 4 If w e accep t the value of E for galvanized pipe from Perry 1 as 0.006 inches, then w e ca n read f=0.012, which makes 4fL / D equal 0 27. We would expect the fluid to squirt highest from the farthest tube, as it does. In a similar experiment, with the 0.25" OD rod in place, it was found that the flow rate from the near tube was about 550 cc / min. By using the hydraulic diameter, as shown in P erry' we can calculate the Reynolds number as 2 x 10 4 Using the same absolute roughness as before yields f=:0.018 4f L / D = 1.25. This indicates that the fluid would sq uirt highest from t he nearest tube, as it does Raising the water viscosity has the same effect as inserting the rod The flow is laminar, and the friction factor is proportional to the viscosity. For the thickened water, the friction factor is large enough that 4f L / D is greater than one; and the water squirts highest from the hole ne ar t he can The whole subject of flow in this type of mani fold has been reviewed by Acrivos e t al 2 The fourth demonstration is much more com plicated to explain than the first three because there is no simple, one-dimensional representa tion of this flow. If we had placed a pitot-type tube in each of the holes, with its exit vertical, w e would expect that from each hole the jet would have risen the same amount if friction were negligible. This result would have been the same, even if the various pitot-t y pe tubes were of different diameters If, however, we had tilted the exits of these pitot-type tubes at differing angles to the vertical, the heights of rise of the jets would not have been equal because, at thei r highest points, the jets would have had varying kinetic energies in the horizontal direction In the fourth demonstration, the fluid forms its own pitot tubes. The wall thickness of the pipe is only about one third of the hole diameter, s o the fluid ca n turn thro ug h the hole without losing all its horizontal momentum. The interesting thing here is that, the faster the fluid is flowing, the greater is the angle through which the fluid must turn to exit; so the fastest-moving fluid exi ts nearest the vertical. One may look at this another way by saying that the fluid builds up a turning vane for itself, made up of stagnant fluid trapped in part of the orifice. This conversion of horizontal to vertical mo mentum is not perfect, so the jet nearest the can 127

PAGE 26

does not rise as high as it would if the conversion were perfect. As we proceed out the pipe, we see two conflicting effects producing the hump-shaped distribution: 1. The increasing efficiency of the "turning vanes" as the velocity falls leads to higher rise; and 2. As the angle through which the fluid must turn to exit decreases, the fluid exits more nearly horizontally and thus does not rise as high. A VARIATION For graduate courses, one may inse rt a 5 / 16" thin-wall tubing about 10" long, open at both ends, into the pipe in place of the rod. In this case the flow through the tube will be great enough that the two end jets will both rise higher than the ones in the middle. This presents an analysis problem suitable for graduate students. SOME PRACTICAL CONSIDERATIONS 1. The pipe connections should be finger tight. A small leak doesn't hurt. 2. In placing the co pper tubes in the holes in pal't No 3, littl e care is needed to align them. After they have been s oft-soldered in place, they can be easily bent into line by holding the pipe in a vise, inserting a steel rod in each tube, and tapping it gently into line with a hammer. 3. To make the pipe without the tubes (part No 2), use extreme care to get the holes in one axial line 4. While running the e xperiments, tilt the plane of the o r ifi ces a few degrees to one side (by rotating the pipe) so that the jets fall free of the pipe and do not int er fere with each other 5. Check the apparatus carefully for burrs They can have a pronounced influ e nc e. 6. In running the first pal't of the experiment, it is well to show that the result is independent of which end of the pipe is inserted in the can. As long as all the con nections are finger tight, the instructor can reverse the position of the pipe in the can quite quicKly. 7. Allow aderiuate time to make up methocel solu tion. Sugar solutions could be substituted, but they are messy Any viscous solution will do, but methocel is prob ably the cheapest and easiest. ACKNOWLEDGMENT Thi s device was used by Dr. J. Q. Cope, former vice president of the Chevron Chemical Corporation, to teach young engineers several important l essons. His procedure was: 1. Describe the apparatus to the new e ngine er, with out mentioning the insertable rod. 2. Ask him from which end of the pipe the jet will squirt highest. 3. When he answers, goad him into betting that he is right. 4. Go get the device, inserting the rod if necessary 128 5. Demonstrate-and take his money. The educational qualities of this procedure are ob vious. NOMENCLATURE D diameter ft f Fanning friction factor F lo st work per pound due to friction ft lbf / lbm g acceleration of gravity ft /sec 2 L length ft m mas s lbm p pressure lbf / in 2 V velocity ft / sec w pump work ft-lbf z elevation ft E abso lut e roughness ft p density lbm / ft3 REFERENCES 1. Perry, J. H. et al. C hemical Engineers' Handbook (4th Ed.; McGraw-Hill, 1963), p. 5-19 et sec 2. Acrivos, A., B. D. Babcock, and R. L. Pigford, Flow Distributions in Manifolds," Chem Eng Science. 10 ( 1!)59), pp 112-124. BOOK REVIEW: (Continued from p. 110) Atom balances, purge and recycle are not dis cussed. Although reactors form a central theme; conversion, yield and extent of reaction are not used or defined. The enumeration of the number of equations (mass balances, mass fraction con straints) does not appear, for this text does not deal with multi-unit processes in multicomponent systems. The mathematical content is such that a stu dent should have finished calculus and differ ential equations. Parenthetically, the student is asked to deal with a large amount of notation to appreciate the content. Computer methods are not stressed, although there is material on numerical methods. Any computer applications would re quire a supplementary text. Linear algebra, which some people refer to as "the language of stoich iometry," is not used. In short, one must compliment the authors on their attempt to inject vitality and meaning into the first text in chemical engineering. However their approach does not fit well in a so-called "standard" core curriculum. Perhaps our curricu la will adapt: I for one concur with their phi losophy. For the present, the book will find use in peripheral ways, such as refresher courses. ROBERT H. KADLEC UNIVERSITY OF MICHIGAN CHEMICAL ENGINEERING EDUCATION

PAGE 27

THE CHE DESIGN LABORATORY HARRY SILLA Ste v ens Institute of Te c hnology Hoboke n ,N.J. 07030 A new design program for senior-undergradu ate chemical engineers was initiated at Stevens Institute of Technology in the 1968-69 academic year. One important feature of the program is the use of the ChE laboratory as a vehicle for teaching design. Because of the emphasis on de sign, this laboratory is called the ChE design laboratory. This paper discusses the philosophy and organization of the laboratory. PHILOSOPHY AND OBJECTIVES A recent report gives the distribution of chemical engineers according to areas of speciali zation. As one would expect, no one categor y pre dominates. For this r eason it does not seem rea sonable to place the emphasis in design educa tion entirely on process design. In order to obtain a broader and more flexible program in design we have added the ChE design laboratory to our course to complement process design. Besides giving a student who is interested in process de sign a broader view the design laboratory also gives the student experience in project engineer ing and the design of experimental systems for research and development. Furthermore, one of the most v aluable experiences any young engi neer can obtain is to follow a project from its con ception through it design stages and finally reduc tion to practice. The design laboratory gives the student this opportunity. The importance of design in research and de velopment needs further discussion. An engineer working in this area must frequently design his own apparatus, and he must usually show results within a year to justify the continuation of a re search project. A considerable amount of valuable research time may be wasted due to errors in the design of apparatus. There are many unpredict able factors in a research project that one cannot afford to be held back by errors in design. Prob ably, some of the recent disenchantment with re* Roethel, D A. H., C ounts, C. R R e alignment s in the Chemical Pro f es s ion Continue, p 90, Nov. 15, 1971. SUMMER 1973 search productivity can be traced back to avoid able delays caused by poor equipment design. At an y rate, the one way a research engineer can increase his producti v it y is b y becoming a skilled designer of equipment. The importance of design in research and development is generally over looked. ANATOMY OF A PROJECT Each student is interviewed and assigned a project according to his interest and ability. The process begins by ha v ing each student make up a resume of his experience, skills and career ob jectives. After the interview the students are formed into teams which consists of a maximum of three students. Teams of two students are optimum, but economics requires that many three man teams be formed. We are willing to undertake many types of projects Our only requirements are that the project is useful; that someone can be found who is knowledgeable in the area to act as an advisor for the project; and that the project can be com pleted at a reasonable cost. A project may involve designing a completely new apparatus or design ing an improvement or addition to an existing system. It should be emphasized that an important objective of the design laboratory is that the stu dents develop the skills re q uired to reduce his design calculations to practice. It is one thing to make design computations and another thing to translate these computations into a working sys tem. A typical project involves a) definition of the problem b) design calculations c) evaluation and purchasing of equipment d) assembling the appa r atus e) testing and trouble shooting f) col lecting correlating data g) and writing the final report. The student is usually given the objectives of his project in a general way. To help define the problem students are required to search the litera ture and read several articles to become familiar with the theory and experimental details. Since the design laborator y involves many different projects, much of the information must be conveyed through personal contact. Thus, the student is urged to seek information from faculty members, graduate students and industry. There are, however, man y aspects of apparatus design 129

PAGE 28

Harry Silla obtained his BS degree from City Univer sity of New York and his MS and PhD ('70) degrees from Stevens Institute of Technology. His research interests include co mbustion and transport properties of flame plasmas. that appear frequently enough to warrant discus sing them in lectures ; for example the design of flow systems. In the design laboratory there is no need to withhold information from the student, that is, the instructor knows the answer to a par ticular problem but withholds the answer to see if the student can arrive at the same answer. There are enough real problems to be solved without creating artificial ones. After making their design calculations the students are ready to select standard parts such as heat exchangers, pumps, valves and instru ments to produce a working system In some cases special parts must be designed and fabricated. This requires a knowledge of materials, equipment and fabrication techni ques Since the students do not have the necessary experience to fabricate equipment, they discuss their designs with the departmental machinist and graduate students who are working on experimental theses. At this point the reliability of their design is also con sidered. Will the apparatus withstand the temp eratures and pressures? Is thermal expansion considered? Are corrosion-resistant materials se lected? Is the apparatus safe? If the necessary equipment is not available in the department's stockroom, students are given equipment catalogs, and they are urged to contact sales engineers to discuss their problems. This aspect of the design forces the students to con sider not only equipment costs but also the im portance of time as a factor in construction of equipment. The students are held responsible for the ac curacy of their work. It is not possible to check 130 all the detailed calculations for the many projects that are being carried out. The laboratory instruc tors and graduate-student advisors, however, be cause of their greater experience will be able to tell if a number or design is reasonable and thus will prevent the student from making any serious errors. It goes without saying that when the students construct and test their equipment their oversights, errors in calculations and planning are emphasized. When a student obtains 90 % on an examination, he walks away pleased, but in the design laboratory this frequently is not enough. To extricate himself from his miscalculations forces him to be very inventive. DESIGN PROJECTS A total of twenty projects are currently under way. These projects are listed in Table l. Some of these projects have been continued from the previous year. For these latter projects, the stu dents begin by reading final reports of last year's graduates, evaluating their recommendations, and outlining a program. This feature of continuing projects adds considerable flexibility to the course, because all projects are eventually completed. Many of our projects are directed toward ex panding our laboratory facilities. Examples of this type of project is the design of a Karr sol vent extraction column and a batch reactor facil ity. These projects will improve our capab iliti S to handle more complex problems in the future. Other projects are to design equipment to col lect engineering or physical property data re quired for design: for example, measuring heat transfer coefficients in falling film evaporator or obtaining vapor-liquid equilibrium data. Admit tedly, designing apparatus for measuring physical property data does not have much glamour, but this can be just as challenging as designing a dis tillation column. One of our more novel projects is the develop ment of a process to extract potential antibiotics from sea sponges. The objective in this project is to extract sufficient material for an organic chemist to determine the structure of biologically active compounds. These compounds will then be synthesized by an organic chemist. A similar pro ject is to determine the sex attractant dispersed by a female lobster. The interest in studying the lob ster is for aquaculture and commercial trapping. The students in this group are designing a Karr* We are grateful to T. C. Lo of the Hoffman-LaRoche Co. for his help in the design of the extractor. CHEMICAL ENGINEERING EDUCATION

PAGE 29

TABLE !-DESIGN LABORATORY PROJECTS Project and Faculty Advisors Separations Extraction of Antibiotics from Sponges, A K. Bose, J Kryschuk H. Silla Extraction of Sex Attractant of Lobsters from Sea Water, A. K. Bose, R. L. Spraggins,b H. Silla Controlled Cycling Solvent Extraction, H. Silla Countercurrent Distribution Solvent Extraction, H. Silla Fluid Bed Drying, H. Silla Filtration H Silla Polymers Design of a Stress Relaxometer, C G Gogos Effect s of Porosity on the Physical Properties of Poly mers, K. C. Valanis Development of a Hydrophilic Gel for a Gel -Permeation Chromatograph, J. A Biesenberger, I. Duvdevani Instrumentation Design of a Ge l-Pe rmeation Chromatograph, J. A. Biesen berger, I. Duvdevani Reaction Engineering Internal Recirculation Catalytic Reactor, G. B. DeLancey, H. Silla Catalytic Plasma Jet Reactor, M. J. McIntosh Fluid Bed Combustion for Waste Treatment, H. Silla Biomedical Engineering Diagnosis of Lung Damage by Measuring Weight Shifts in the Upper Body, J. R. Kaim c H. Silla Ultrasonic Generation of Monodispersed Submicron Particles for Lung Studies, M. Lippmann H. Silla Engineering Properties Heat Transfer in a Fluid Bed, M Sacks H. Silla Flow in a Fluid Bed, M. Sacks H. Silla Heat Transfer in a Falling Film Exaporator, H. Silla Plate Efficiencies of a Sieve Plate Distillation Column, H. Silla Transport Phenomena in a Flame Plasma, H. Silla a. Doctoral student b Post-Doctoral Research Associate c. M.D., College of Medicine and Dentistry of New Jersey at Newark d. Ph.D., New York University Medical Center extraction colum to remove the sex attractant from sea water. Each year there are a few students who are in terested in biomedical engineering or who intend to go to medical school. To satisfy this group of students we have established a working relation ship with a local hospital to generate medical projects. Last year two students designed and built an automatic blood sampler which is now being used by the hospital. ** There is a need for SUMMER 1973 Besides giving a student ... in process design a broader view, the design laboratory also gives the student experience in project engineering and the design of experimental systems for research and development. rapidly locating which lung is damaged because of accidents or diseases. This is not as simple as it may appear. The student involved in this project is investigating the possibility of measuring the shift in the center of gravity of the individual during his breathing cycle. During inspiration the heart shifts in the direction of the damaged lung, thus causing a shift in the individual's cen ter of gravity. The design of instrumentation is a rich source of projects and an area where many principles of chemical engineering can be applied on a minia ture scale. Gel-permeation chromatography is an example of a project of this type. In this project the students were assigned the problem of rede signing an existing chromatograph with the ob jective of making a more reliable compact instru ment. CONCLUSIONS The design laboratory has been enthusiastic ally accepted by the students, who have christened the design laboratory, "The Super Lab." Even students who have had no prior interest in design or who have chosen other areas of specialization have been challenged by the projects. The design laboratory not only is a challenge to the student, but to the instructor as well because of the variety of projects that must be managed, and because the projects are constantly changing. The design laboratory is still in the process of evolving, and many problems will have to be solved before the laboratory reaches maturity, nevertheless, the results to date have been grati fying. One can see a student arrive in the Fall in "rough form" and then leave in the Spring as a much improved engineer. We have reached the point in the design laboratory where we feel that many of the design projects are equivalent to industrial experience. The design laboratory should play an important role in the undergradu ate chemical engineering curriculum. ** We are grateful to Dr. W. Perl of the College of Medicine and Dentistry of New Jersey at Newark for his help in the design of the sampler. 131

PAGE 30

FLOW MODELING AND PARAMETER ESTIMATION USING RADIOTRACERS R. W. ROUSSEAU, R. P. GARDNER and R.M.FELDER North Carolina State University Raleigh, North Carolina 27607 A common method of formulating dynamic models is to introduce a process upset (such as a tracer injection) and to measure the subsequent response. There are several important restrictions on the use of this method: the upset must be measurable without being dramatic enough to cause system failure, the production of off specification product, or a threat to the safety of people and / or equipment; in addition, the experi menter must have access to the process stream, either through a control valve or tracer injection site, and he must have the capability of monitor ing the process response. The latter requirement can be fulfilled in many industrial systems only if a radioactive isotope is used as a tracer. In the experiment to be described, a radio tracer impulse is injected into a turbulent stream flowing irt a straight pipe, and the count rate at two downstream points is measured as a function of time. The results are used to determine dis persion model parameters (mean residence time and effective axial dispersion coefficient) by the method of moments. The estimated values of the dispersion coefficient are then compared with values predicted by a published dimensionless correlation of Peclet number vs. Reynolds num ber. The educational objectives of the experiment are to expose the students to the concepts of process modeling and experimental determination of model parameters, to lay a basis for subsequent presentation of material on process dynamics and the design and scaleup of nonideal process vessels, and to introduce the topics of tracer technology, radiosotopes handling and radiation detection, subjects not usually encountered in the under graduate chemical engineering curriculum. The background material presented to the class covers fully the problems associated with radioactive materials, and discusses alternative tracers such as dyes and electrolytes. It also 132 briefly reviews problems which have been success fully attacked using radioisotopes (many of which are presented in the work by Gardner and Ely (1967)), including the determination of flow rates and flow channel volumes in process units blood vessels and rivers and streams, formulation of models for industrial processes and biological systems, measurements of diffusion coefficients and kinetic rate constants, measurements of mix ing efficiencies in stirred tanks, determination of the existence of channelling or bypassing and stagnant regions in process units, and measure ments of currents and dispersion patterns in re ceiving waters. We believe that this list, as exten sive as it is, represents only a fraction of the potential applications of radioisotopes to the solu tion of problems with which chemical engineers are likely to be confronted, and that having once been introduced to radioisotopes in their educa tion, engineers will be more likely to think of them when dealing with such problems. EXPERIMENT AL A s chematic of the experimental s ystem is shown in Figure 1. Water is fed to the system from a constant head tank through a rotameter into a long inch NPD galvanized pipe, and from the pipe into a storage tank. Constant Head Tonk Pump ~ De tectors ~ Injection <:.!_ n "-314" NPD Rotameters l (I Sto.age I) Fig. 1 Schematic of Experiment Sewer Tracer is injected into the pipe through a regular pipe tee fitted with a rubber septum. Detectors are mounted at either end of a 20 foot straight section of the pipe down stream of the tracer injection point. The storage tank is used to allow the radioactivity to decay to a negligible level before the effluent is sewered. CHEMICAL ENGINEERING EDUCATION

PAGE 31

Ronald W. Rousseau received his BS, MS, and PhD from Louisia n a State University. He has industrial experience with the Ethy l Corporation and Westvaco, Inc. He has been at North Carolina State University since 1969; re search in t erests include crystallization, vapor liquid equilibria, process modeling and applied polymer chem istry. He teaches mass and energy balance calculations, t ransport processes and mass transfer operations. Robin P Gardner received his BChE and MS from North Caroli n a State University and his PhD from Pennsylvania State U n iversity. From 1961 63 he was Scientist in Charge of Short Courses on Radioisotope Applications in Indus try at the Oak Ridge Institute of Nuclear Studies and l ater was Assistant Director of the Measurement and Controls Lab at the Research Triangle Institute. He was an IAEA Expert at the Institute of Radioactive Research in Belo Horizonte, Brazil and currently is Professor of Nuc l ear and Chemical Engineering at NCSU. (center) Ric h ard M. Felder did his undergraduate work at the City Co ll ege of New York and obtained his PhD from Princeton He spent a year at AERE Harwell, England o n a NATO Postdoctora l Fellowship, two years at Brook haven National Laboratory, and came to NCSU in 1969 Recent l y he has become involved with photochemical re actor ana l ysis, radioisoto pe applications, and applica tions of engineering technology to medical and environ menta l problems He has served as a consultant to the government of Brazil on industrial application of radio isotopes. (right) Ma n ga n ese-56, i n the form of an aqueous Mn(NO 3 ) 2 solution, was se l ected as the tracer because it is a gamma ray emitter and hence can be detected through metal walls, and because it has a half-life of only 2.6 hours, which causes it to decay to negligible levels in less than 24 h ours Geiger Mue ll er tubes were the detectors; their o ut puts were fed to a Nuclear Chicago rate meter coupled to a Leeds a n d Northrup strip chart recorder. Both sing l e and two-point detection methods were demonstrated in the experiments, using detectors placed at dista n ces of 6 and 26 feet from the point of i n jection. Whi l e i t is desirable that the detectors have approxi mate l y the same sensitivity, deviations from this condi tion are not serious because of the method of data SU MM E R 1 97 3 analysis. Typical output from a run using both detectors is shown in Figure 2, which plots the counting rates re corded by the first and second detector vs. the time from inje c tion 70 60 UI .. 50 0 J e lLI 40 I<( a: (.!) z 30 z :::> 0 (.) 20 1 0 35 30 25 20 1 5 10 5 0 T IME sec Fig 2 Ty p ica l An a log Output COMPUTATIONAL PROCE D URES Flow systems in which a measurable b u t fi n ite a m ount of axial mixing occurs are com m on l y simulated by two-parameter models, such as axial dispersion and tanks in-series models. T he para m eters of these models are simply related to m ments of the system impulse response funct i on, 133

PAGE 32

and may be conveniently estimated from numeri cally calculated moments of experimental re sponse curves. In contrast, parameter estimation techniques such as time-domain and frequency domain regression require considerable computa tional effort, and are consequently less suitable for inclusion in a junior-level laboratory course. The quantities needed to estimate the para meters of a twoparameter flow model by the method of moments are ( tR 1 (t)dt i = [ Ri(t)dt 0 [ (t1 ) 2 R/t)dt 2 0 ai =-(=-R-i-(t-)-dt __ i = 1, 2 (1) i = 1,2 ( 2 ) where Ri (t) is ch :) countiag rate at the i t h detec tion station, and ui and ui 2 are respectively the mean and variance of this function. The pro cedure is to choose a model, derive expressions for the model parameters in terms of ui and u i2 evaluate the latter quantities from the experi mental impulse responses and Eqs. (1) and(2) by numerical quadrature, a nd use the resulting values to solve for the model parameters. In the experiments run so far, hand calculations of t he moments from analog output w ere required; in the future, the output from the rate meter will be punched on paper tape, which will in turn be used as input to a Simpson's Rule quadrature subroutine. The model chosen for illustrative purposes was the doubly-infinite axial dispersion model. The assumptions inherent in this model and so lutions for the impulse response and its moments are outlined by Himmelblau and Bischoff (1968) and Levenspiel (1972). The relations used in the single-detector :measurements are as follows: i = 1,2 (3) 2 a i 2 + 8 a n d p = vL /D ( 4, 5 ) 2 = P. ;z i 1 i 1 i where Li is the distance from the injection point to the i t h detector, v is the mean flow velocity in the tube, and D is the effective axial dispersion coefficient. The procedure followed was to calcu late u i and a2 from the exper i mental Ri data us ing Eqs. (1) and (2), then to evaluate the v locity v from Eq. (3), the Peclet number P i from Eq. (4), and finall y D from Eq. (5). The t w detector method provides two advantages ove r 134 the single detector method: the injection does not have to be a perfect impulse, and errors in syn chronizing the time of injection with the record er output are eliminated. The equations for the b v o detector method are L2-Ll -v= -l 2 2 0 2 0 1 2 2 p (-111) v(L 2 -L 1 ) p =--D(6) (7 ) (8) In this case the velocity v is calculated from the numerical moments using Eq. (6) the Peclet number P is calculated from Eq. (7), and D i s calculated from Eq. (8). Table 1 shows values of flow velocities deter mined with a rotameter and calculated as out lined above. It is interesting to compare the reT a ble 1-Flow Velocitie s Run u(from rotameter) 1 U l 2 1 2.0lft / sec 1.77 1.8 8 1. 93 2 1.5 3 1.07 1. 37 1.49 3 1.0 0. 938 0 .9 45 0 9 9 4 1.0 1.0 3 suits obtained by the oneand two-point tech niques: the average error is 16 % for the single detector at 6 feet, 6 % for the single detector at 26 feet, and 2 % for the two detectors. Figure 3 in a plot of the effective axial dispersion coeffi cient vs. the Reynolds number, and shows that the data fall within the range predicted by a ~40 ,c u30 :: ~20 z 0 en 4 a: LIJ 3; 3 i5 2 Accepted Experimental Range 2 3 4 5 6 78910 20 30 40 5060708090 REYNOLDS NUMBER x 10" 3 Fig. 3. Dispersion Coefficient as a Function of Reynolds Number. CHEMICAL ENGINEERING EDUCATION

PAGE 33

The educational objectives of the experiment are to expose the student to the concepts of process modeling and experimental determination of model parameters ... correlation reprinted by Himmelblau and Bischoff (1968). Since doing so would not serve any par ticular purpose in light of the educational objec tives of the experiment, we have not attempted to confirm the negligibility of ads orption other than to note the absence of long tails on the im pulse response curves. DISCUSSION The students are given two 3-hour laborato ry periods to complete the experiment. In the first period they go throu,gh the entire experiment without actually using the radiotracer. Under this format they each get a chance to become familiar with the equipm e nt and injection procedure with out the worry of spills or other hazards. Also during the first 3-hour session they are instructed in fundamentals of radiation detection, particu larly as related to Geiger-Mueller characteristics, and in radiation safety. In the second 3-hour period the actual runs are made, but the injec tions and tracer handling are not done by the students, who merely observe. The runs them selves are not particularly time-consuming, so that each student has sufficient time to carry out the necessary calculations and to seek individual instruction on any aspect of the experiment. The participating st udent s appeared to get a great deal out of the experiment; the only strong objection was to the necessity of calculating mo ments graphically from analog output, a require ment which will be eliminated in the future when digital output equipment becomes available. A potential problem with an experiment of this sort being given on a junior level is that the students may ha ve to accept on faith the utility o f much of what they are doing. This did not appear to be a matter of concern to the students, however possibly due in part to the fact that they had been introduced to elementary concepts of mod el ing ( and in particul ar to the d yna mic response of a first-order process) in a previous cours e. 'J'he experiment also served to make related material subsequently encountered in senior courses on reactor design and process dynamics and control a great deal more meaningful to those who par ticipated in it. SUMMER 1973 Once the basic procedure for a stimulus response experiment of this type has been estab lished, it is a relatively easy matter to study a variety of flow systems using the same technique. We are currently making provisions for the fol lowing experiments : 1. Flow an d disp ers ion in packed column s 2 F l ow in obstructed tubes 3. Detection of stagnancy and channeling 4. Residence tim e distribution of stirred tanks in series 5. Va r i ation of RTD with st irring rate in a single stirred tank-determination of mixing efficie ncy. 6 Impul se responses of lam inar flow systems. Our pre se nt plan is to include one of these ex periments (probably the one on the packed col umn) in the l aboratory course, either in addition to or instead of the empty tube 2x periment, a nd to use the others as senior projects. REFERENCES Gardner, R. P. and R. L Ely, Jr., "Radioisotope Measure ment and Applications in Engineering," Reinhold Pub li s hin g Co., 1967. Himm e l b l au, D. M. and K. B. Bischoff, "Process Analysis a nd Simulation, C h ap ter 4, John Wiley and Sons Inc ., 1968. Levenspiel, 0., Chem i ca l Reaction Engineering," Chapter 9, John \,Viley and Sons, Inc., 1972. LAB WORKSHOP (Continued from p. 1 2 5} D. J. Graves discussed the use of audio-visual packages in the preparation phase of the labora tory experiment. The student prepared modules used to describe complex pieces of equipment, measurements points, flow paths, and complex procedures. At the University of Pennsylvania the audio-visual modules have reduced laboratory time and allowed students to continue to work on project experiments after previous groups have graduated. Two sample audio-visual modules were shown to illustrate their use with typical experi ments. The entire proceedings of the laboratory work shop are to be published and can be obtained by sending a check for $10.00 payable to The Uni versity of Michigan to Professor H. Scott Fogler, Department of Chemical Engineering, The Uni versity of Michigan Ann Arbor, Michigan 48104. The price of the bound proceedings, which will be available after May 1, 1973 was established by the ASEE ChE Division in order to minimize any loss of funds from printing costs. 135

PAGE 34

A COMPUTERIZED UNDERGRADUATE PROCESS DYNAMICS AND CONTROL LABORATORY R. A. SCHMITZ University of Illinois Urbana, IL 61801 A project to computerize the undergraduate process dynamics and control laboratory in the Department of Chemical Engineering at the Uni versity of Illinois was begun in 1969. The plan was to use an existing IBM 1800 computer, which was operating on a time-sharing basis in the School of Chemical Sciences, to provide a facility for computer-aided instruction and for computer aided experiments by undergraduate students. Our motivation for the project was the realization that a facility of this type wou ld permit more ex tensive and more meaningful laboratory studies of process dynamics, simulation and control than are possible in conventionally-equipped labora tories. We also felt that the hands-on use of an on-line data acquisition and control system would be a valuab le experience for the students and that the lecture portion of certain courses would be greatly improved by the demonstrations and vis ual displays made possible by an on-line com puter. Similar projects have been undertaken at a few other chemical engineering departments at universities in the United States and Canada 1 1 A recent report of the CACHE ( Computer Aids in Chemical Engineering Education) Committee 8 presents a brief description of these activities. Certainly at this point in time, the use of a computerized undergraduate laboratory in ChE education is a relatively new development. Since the few facilities that are in existence were estab lished quite dependently, each incorporates some unique features, and publications of their descrip tions should be informat ive and valuable to other departments which may embark on similar proj ects. Many such departments will probably find themselves in a situation similar to ours at Illinois at the outset of this project; that is, with an accessible time-sharing computer of the large or medium-sized variety and a:n existing laboratory equipped with conventional instruments and con trollers. While the task of interfacing the labora tory and the computer and of developing a soft ware system in such cases may be demanding in 136 Ro ger A. Schmitz r ecei v ed his BS degree fro m the University of Illinoi s and his PhD from the Univer sity of Minnesota. He joined th e C hE faculty at the University of lllnnois in 1962. His area of specia lization is the stab il ity and control of c hemically r e actin g systems H e was awarded a Guggenheim Fellow s hip in 1968-69 and was the recipient of the Allan P. Colburn award of th e AIChE in 1970. terms of labor, the investment of dollars in hard ware should be minimal. Departments not so for tunately situated with regard to an existing com puting facility will probably go the route of in vesting in a minicomputer. THE SYSTEM AND ITS OPERATION The IBM 1800 computer in the School of Chemical Sciences has 32,000 words of core memory and uses three disk s (500,000 words each) for auxiliary storage. It is equipped with the usual p er ipherals including (1) an analog-to-digital (A/D) converter capable of receiving s ignals on a -5 to + 5 vo lt range, (2) a digital-to-analog ( D / A) converter capable of sendi ng voltages on the range O to +5 volts and (3) a car d reader. A description of the computer system, the monitoring program and IBM's Time-Sharing Executive (TSX) System has been published. D Three thirty-conducto r cables connect the computer to the proc ess control laboratory. These cables actually branch to nine stations connected in parallel. Four of these ar e chemical engineering research laboratorie s, another is a te rm inal in a room housing an EAI 580 analog computer, and th e re mainin g four are in the process control labo r atory. On e cable is devoted entirely to an IBM 1053 output printer which can be connected at any of the s tation s A user at any s tation in the process control labora tor y has access to AID and D / A channels, a process in terrupt switch, digital input s ( two-position switches) and CHEMICAL ENGINEERING EDUCATION

PAGE 35

T ronsducers ~~-----'-< >I Amplifiers Drivers -5 to +5v IBM 1053 Printer PROC E SS (l) l iq. level (2) heat exch (3) pH in CSTR Disk -Stored Programs Transducers 0 to +5v 3 tol5 psi A/D I BM 1800 D/A Fi g I. S chematic D i a g r a m o f C los e dL oop S yste ms digital outputs (lights) Altogether there are eight A/D and four D / A channels, nine lights, and nine switches. The switches and lights allow for user inputs to the stored programs and for user options. To gain access to the disk-stored programs :for the proces s control laboratory, the u ser at any station must activate the process interrupt sw itch. This causes the transfer into core and the exec ution of an initializing program which governs the building of the core load for the process control laboratory. The core load consists of a supervisory program along with associated sub programs and the subroutines used-all initial'.y stored in disk memor y When core-load building is complete, execution of the supervisory program begins. It first in structs the computer to flash two lights at all stations in the laboratory repeatedly, waiting for the useito select, by m e ans of switch settings, a desired subprogram. As it is p resent l y written, the s up erv isory program can accommodate twenty-seven different subprograms each having a different three-digit code number. To call a desired subprogram, the user enters the three integers in the appropl'iate code number s ucce ssi vely in binary form using the two sw itches at his experiment station. After a three-digit code is entered, the supervisory program branches to the subprogram stored under that code. Upon completion of the subprogram, control is returned to the supervisor, lights are again flashed at all stations wait ing for another subprogram to be called. In the u sua l operation of the laboratory, the initi aliza tion procedure s are h a ndled by the instructor or the laboratory assistant. The student then encounters the sys t e m and takes over its operation with the supervisory program beingexecuted; that is, with lights flashing in wait of a subprogram code to be entered. The students are responsible for the writing, disk-storing, and d e bugging of the subprograms. They ordinarily work in three-man groups, and each group is assigned a sub program code number for the course. The subject of programming will be taken up in more detail in a later section of this peper Only one subprogram can be executed at a time as the system presently stands. This means that no two experiments in the control laboratory, both using the computer, can be carried out s imultaneous l y V le can make programming modifications to remove this limita tion if it becomes necessary to do so. SUMMER 1973 As mentioned eal'lier, the computel' operates on a time-sharing basis. For background jobs, that is those not involving real -ti me applicat ion s, each user's core load resides in the core and is executed fol' a shol't time befol'e being "swapped" to disk storage for a period of time. Our system monitor program presently allots a time s lice of twenty seconds for core residence time. Muc h of the computer usage in the process co ntrol laboratory falls into this background category. Those programs, however, which make use of the real-time clock; that is, those which ca ll for frequent interrupts for reading and/ or sending analog signals at specified intervals of times, have priority status and are not swapped from the core. The computer services these frequent interrupts as a fore ground task, returning to background jobs in the interim periods. THE L A B O RA TORY The equipment at each of three of the four stations in the process control laboratory com prises a simple control loop with a single meas ured variable and one manipulated variable. One of these involves the control of the liquid level in a cylindrical column packed with Plexiglass spheres; another, the control of temperature of the effluent water from a tube-and-shell heat ex changer; and the third, the control of pH in a stirred vessel. Each of the three setups, which are represented schematically in Figure 1, involves standard measuring and signal transducing de vices so as to produce de voltage signals for the measured variables on the range -5 to +5 volts for input to the A / D converter on the computer. The measurement originates from a process pres sure (hydrostatic head)-to-current transducer in the liquid level system, from a thermocouple in the heat exchanger and from a submerged pH electrode assembly in the stirred vessel. The D / A signal from the computer is converted to a cur rent and then to an air pressure signal in the Fig 2 Photogaph of Liquid Level Control System 137

PAGE 36

range 3 to 15 psi. The pneumatic signal is sent to a diaphragm control valve, the final control ele ment in all three cases. The manipulated variables are (1) the flow rate of water to the packed column of the liquid level system, (2) the steam pressure on the tube side of the heat exchanger and (3) the flow rate of a hydrochloric acid solu tion to the stirred vessel. The photograph in Figure 2 shows the physi cal layout of the liquid level system; the others are similar. As shown in the photograph, each station is equipped with a control panel on which the process signal flow is printed. A close-up view of the control panel for the liquid level process is shown in Figure 3. The panel concea l s most of the fig. 3. Operator's Control Panel for Liquid Level Experiment. wiring connections and interfacing equipment. As can be seen in the photograph of Figure 3, the panel contains a process interrupt switch, two lights ( digital outputs) and two switches ( digital inputs) As is also shown in the photographs, each of the three systems is equipped with a con ventional three-mode analog controller which can be switched into or out of the loop as desired. The equipment and the wiring connections for these systems are intended to be permanent. In working with these processes, therefore, the stu dent in the laboratory does not assemble appara tus or make any interface connections. Typical experiments with the three systems may involve the formulation and testing of mathematical models via step response, frequency response and analog simulation methods, and in vestigations of the closed-loop behavior both with direct digital control and with conventional con trol. In all experiments the subprogra ms called by the experimenter may contain instructions to read and store data, send feedback signals, dis138 play experimental results on an oscilloscope, carry out calculations and print results or data on the output printer. Further description of the programming effort required will be given in the next section. A fourth apparatus, which makes use of the computer facility, consists of two different types of pneumatic control valves and associated signal converting and conditioning hardware. Experi ments with this setup, depicted schematically in Figure 4, can be carried out using the control panel at the pH control apparatus. As shown on the left porton of Figure 4, voltage signals from the computer may be sent to the valves, separ ately or simultaneously, and voltage signals, orig inating from displacement transducers attached to the valve stems, may be sent to the A/D con verter on the computer. In the simplest experi ments with this system, the objective would be to study and compare the frequency response of the two valves. In such instances the subprogram called by the student would instruct the computer to send a sinusoidal signal of a specified ampli tude and frequency to the valves and to read a vo ltage signal which indicates the instantaneous valve positions. If he so desires, the student may easily have his subprogram analyze the data and print information to be used in constructing a Bode diagram. He may also have results dis played on an oscilloscope. With an analog computer inserted in the sys tem, as shown in Figure 4, real-time simulations involving the simulation of some process on the analog computer and incorporating real valve dynamics are feasible. In experiments of this type, the student may study the effects of non ideal valve dynamics in various control loops by experimenting with simulated feedback systems Amplifiers Drivers Control Valves D/A (a) Diaphragm Actuator t----1 (bl Piston Actuator Displacement Transducer s 4 8 VDC/inch IBM 18DO A/D Analog Computer (EAi 580 or TR 10) Process Simulation in Reol Time fig. 4 System for Valve Dynamics Experiments and Real-Time Simulations. CHEMICAL ENGINEERING EDUCATION

PAGE 37

containing ideally simulated valves in one instance and the real valves in another. It will also be possible in advanced studies to interconnect the analog computer, digital computer and any or all of the laboratory stations to form a complex multivariable system containing some simulated components and some real ones A TR-10 analog computer is available in the laboratory for some small scale experiments and an EAI 580 is housed at a separate station for more extensive simulations. For either computer, the linkage from the patch panel on the analog machine to the cables from the IBM 1800 is made through a portable interface panel. The panel provides access to all D / A and A / D channels to the IBM 1800 and to all nine lights and switches. The photograph in Figure 5 shows an interconnected system comprising the TR-10 analog computer, the IBM 1800, the interface panel and a pneuma tic control valve. This system was set up to demonstrate a real-time simulation of a chemical reactor under direct digital control. The fourth station in the process control laboratory consists simply of a laboratory bench at which the portable interface panel can be con nected to the cables from the computer. The pur pose of this station is to provide a versatile gen eral-purpose facility at which a variety of bench top experiments or demonstrations can be set up and carried out in a short time, some perhaps on a one-shot basis. Usually these experiments will involve studies of the dynamics of individual components or devices. A simple example is a study of the dynamics of thermocouples with Fig 5. Photograph Show ing a System Consisting of a Pneumatic Control Valve, a Portable Interface Panel to the IBM 1800 Computer and a TR-IO Analog Computer being used in a Real-Time Simulation by an Undergraduate Student. SUMMER 1973 ANDIG ANLOG DIGAN DISPY FLASH PEROD PRINT TAHLE I. S'J BROUTIKI :: DESCRIPTIONS Function Read and print the instantMeous voltage on A/D channel(s ) specified in arguments in the calling statement. Periodically read A/D channel s send voltages on D/ A channel(s) (see options below) and store data The sampling period and channel numbers are specified in arguments in the calling statement Options: (a) data logging, no D/A signals (b) data logging v1th proportion a l D/A signal :for feedback control (c) data logging with function gener a tion (D/A voltage) for analog simulations ( d) combination or (b) and ( c). Send and holds. voltage on D/A channel(s). The magnitude of the voltage(s) and the channel number(s) are spe cified argum ents Send voltage data stored in INSKEL common arrays (e.g stored during real time operations) for oscilloscope display (i.e cycle through the arrays). The arrays to be displayed and tbe variables for the x and Y axis are specified arguments. Flash lights and va.it for s v itches (digital inputs) or process interrupt to be set before proceeding Light number( s) and flashing frequency are specified a rguments. Send sinusoidal voltag e on a D/A chan nel an\1 log dat a from A/D channel( s) The frequency and period of the sine function and the channel numbers are specified parameters. An optio n in the su broutine p ermi ts the user to specify some other periodic function (tabulated) in place of the sine function Print voltage data stored in INSKEL canmon arreys ( e, g. stored during real tim e operations) The arrays to be tabulated are specified in arguments in the calling statement. various types of shielding, the computer being used to read, store, print and display the thermo couple signals versus time. As previously indicated, an oscilloscope with an attached Polaroid camera, is available in the laboratory. Thus, by employing a display subrou tine as described in the following section, a stu dent can immediately observe his experimental data and obtain a photograph for insertion in his laboratory report. PROGRAMMING In order to keep student programming re quirements and de-bugging difficulties at a man ageable level, we have written a number of basic programs for the process control laboratory and have stored them permanently on one of the disks. In addition to the initializing and supervisory programs which are transferred into core memory during initialization procedures, these include a number of subroutines whose functions include reading voltages, sending feedback sig nals, storing, displaying and printing data and governing lights and switches A list of these routines along with a very brief description of each is given in Table I. A complete description of these routines is not essential here, but per haps a few comments in addition to those given in Table I, on some of them are called for. Each subroutine is accessible through a standard Fort ran call statement that includes a list of argu139

PAGE 38

ments. Three of the routines, namely ANLOG, DISPY and PEROD, handle real -time operations. Those routines subsequently branch to various entry points in an assembly language program, also written by us specifically for the process con trol laboratory, which resides permanently in the core memory initialization. Thus by means of Fortran calls to these three subroutines, the user has access to a variety of real-time operations. The initiation and termination of the rea l-time operations of data logging and sending by the computer in ANLOG and PEROD are handled by the student at the experiment site by means of switch settings For example, when subroutine ANLOG is entered, a light is flashed (the light number is specified in the list of arguments) Periodic voltage readings and sendings begin when the corresponding switch is turned on. The reading and sending end and the execution of the next statement in the student's subprogram takes place when that switch is turned off. In the meanwhile, the user can call for the storing of data over intervals of time during which a second switch (the number of which is also specified in the argument list) is turned on. The usage of subroutine PEROD is very similar. It should be noted that the subroutines in their present form do not permit the changing of parameters during the course of rea l-time opera tions. Thus the values of the proportional band sampling interval, etc., are specified prior to the call or in the calling statement of ANLOG and cannot be changed during the execution of that subroutine In order to study various values of these parameters, the student would either have to call his subprogram repeatedly or have in serted his call statement within a loop for repeti tive calls. As mentioned earlier, the student is required to write the Fortran subprogram to which the supervisory program branches when a certain combination of switch settings is entered. Be cause of the available subroutines, this pro gramming requirement is simple. For example, the following sequence of statements constitutes the set of necessary instructions for execut in g direct digital control with data logging, followed by an oscilloscope display and printing of stored data: 140 CALL ANLOG (parameters) CALL DISPY (parameters) CALL PRINT (parameters). A study of frequency response would require the substitution of "CALL PEROD (para meters)" in place of the call to ANLOG. Of course, the student may make his program quite involved to the extent of providing various ex perimental options and of carrying out calcula tions with the experimental data if he so desires. Though the minimal programming require ment is quite simple, nearly trivial for some ex ercises, we feel that it is an important part of the student's usage of the system. It gives him a greater overall appreciation and understanding of his experimental goals, of our particular sys tem and of software aspects associated with on line computing in general. Having to write a com puter program for his experiment in advance of the laboratory session forces the student to study the experiment carefully and to plan his labora tory procedure step-by-step. This in itself is a noteworthy benefit of a computerized laboratory in which the students are required to program the experiments. In the operation of the laboratory, the labora tory assistant or instructor assists the students in disk-storing and de-bugging their subprograms on the afternoon preceding the scheduled labora tory session. Some additional de-bugging is often required during laboratory meetings. As men tioned earlier, the students work in three-man teams, and therefore programming is a group effort. Our curriculum contains a required course in digital computer programming in the fresh man or sophomore year. In addition, the students will have used Fortran programming in carrying out assignments in a few courses prior to their enrollment in the process control course. In our initial or "trial" usage of the sys tem (Fall semester, 1972) the students carried out three computer-aided experiments. We were able to give adequate programming instruction in two 90-minute workshop sessions early in the semester. The sessions included a general discussion of on-line computing and computing control in addition to specific instructions and : exercises on the usage of our system. Each student was given a laboratory manual which described the computerized laboratory and con tained instructions on the usage of disk-stored subroutines and on the preparation of the required subprograms It also contained sev eral example subprograms. The workshop ses sions were followed by laboratory demonstra tions. We found that the preparatory instrucCHEMICAL ENGINEERING EDUCATION

PAGE 39

tions so given were quite adequate. The students were able to proceed from that stage at the level of independence which we had sought. With some minor revisions in the manual and subroutine functions, we plan to introduce several additional computer-aided experiments for the Fall term, 1973. CONCLUSION In this paper we have described briefly our system for computer-aided experiments in an undergraduate process dynamics and control lab oratory at the University of Illinois. We have included some description of its usage but will elaborate further on the course description and on the specific laboratory experiments and dem onstrations in future publications. In designing the apparatus and the computer programs for the system, we placed much value on retaining basic simplicity so that students, in an introductory course, would be able to under stand the operations of an on-line computing facility and be able to use it to advantage on a hands-on basis. We also strived for versatility so that new experiments could be incorporated easily and that utilization of the system could be extended to more advanced topics, to very com plex networks and even perhaps to courses on other subjects, such as applied kinetics We also felt that it was important to leave the programming of experiments to the student, but we have made available a number of subrou tines which make this task relatively simple. There is a strong temptation for instructors in such laboratories to program the experiments completely and reduce the role of the student to that of executing the programs. While such ex periments may be elegantly programmed and virtually fail-safe, they may also stifle most of the student's thought input. With the student in volvement in programming, even at a very simple level, a greater appreciation of process-computer interfacing is imparted, a greater degree of open endedness is automatically provided and presum ably more thought input creativity, originality and interest on the part of the student will be realized. Our facility was employed for the first time in an introductory undergraduate course on pro cess dynamics and control in the Fall semester, 1972. Three computer-aided experiments con ducted by the students and two demonstrations carried out by the author of this paper, were SUMMER 1973 used, and the concensus of opinions of students, assistants and instructor was that the endeavor was highly successful. The student interest and e nthusiasm for the laborato ry were noticeably greater than they had been in previous years when similar experiments were conducted with out the aid of the computer. We plan to introduce several additional experiments and demonstra tions for the next offering of the course (Fall, 1973) It will be possible to discuss more defini tive results and to present rea listic evaluations after a few more semesters of experience. Hope fully, the system we have developed as well as our experiences in implementation will be helpful to others embarking on similar projects. ACKNOWLEDGEMENTS Thi s project receive d most of its financial s uppo rt throu g h a grant from the National Science Foundation. D epar tmental help was provided mainly in the form of gradua te teaching assis tant s and laboratory instruc t ors. Most of the e l ectron i c interfacing hardwar e was designed and built i n the electronics shop in the School of Chemi ca l Scien c es. The s taff of th e School's computer lab pro vided help with much of the basic programming. The author would lik e to acknowledge particularly the val uabl e ass i sta nc e of Mrs. Pat Anderson with programming and the work of Dr. Ming Fang who designed and in s talled mu ch of th e hardware and apparatus. BIBLIOGRAPHY 1. C h ristense n, J H. and P. M. Vargo, "Education in Real-Time Computing", Chem Engr Ed. 5, 30 (1971). 2. Fisher, D. G., "Real-Time Computing in the Uni versity", Chem. Engr. Ed ., 5, 24 (1971). 3. Westerberg, A W. and R. C. Eschenbacher, "A Real-Time Compute1 Control Facility", Chem. Engr. Ed., 5, 32 (1971). 4 Wright, J D., "Education in Computer Control: How to Make Your Real-Time C lo ck Tick', Pulp and Paper Magazine of Canada, 72, 4, 29 (1971). 5. Idie r, M. and D. A. Mellichamp, "Computer Moni toring and Contro l of a Process Dynamics Labora tory', Paper No. 4b, 71st National Meeting of AIChE, Dallas, Feb., 1972. 6 Wissler, E. H., "Computer Aided Methods for Chemical Engineering Laboratories", Paper No. 4a, 71st National Meeting of AIChE Dallas, Feb., 1972. 7. Moore, C. F "A General Purpose Data Acquisition and Control Utility," 7th Annual Conf on Use Digital Computers in Process Control, Louisiana State University, Feb., 1972. 8. Elzy, E., L. B. Evans, R. C Weaver and A. W. Westerberg, "Real-Time Digital Computer Systems in Undergraduate Education Paper No. 47c, 72nd National Meeting of AIChE, St. Louis, May, 1972. 9 Secrest, Don "Time-Sharing Experimental Control on a Small Computer", I&EC 60, 6, 74, 1968. 141

PAGE 40

cjn:I i nternational A NEW TRADITIONAL UNIT OPERA TIONS LABORATORY COURSE AAGE FRED E NSLUND Instituttet for Kemiteknik Danmarks Tekiniske Hojskole 2800 Lyngby, Denmark In 1968 the Department of Chemical Tech nology, the Technical University of Denmark, moved from an old location in central Copenhagen to a modern, spacious campus north of town. The department was given adequate funds to de velop new laboratory courses, and a new, tradi tional unit operations laboratory course is now completed It is the purpose of this communica tion to describe the course in some detail so that other chem i cal engineering departments may benefit from this experience The author will gladly furnish further information regarding de tails of the course upon request. Before proceed ing further, it is necessary to explain the purpose of the course PURPOSE OF THE COURSE It is characteristic for the Danish chemical industry that it consists of many rather small units. One can therefore not depend on the indus try to give chemical engineering graduates a professional, rounded technical training program. This, and the fact that the ChE students are sub jected to a thorough physics laborato_ry co~rse early in the curriculum, indicate that m design ing the unit operations laboratory course, one should emphasize real process equipment rather than physical phenomena That is to say that the course should be based on equipment resembling process equipment rather than transport phe nomena experiments. 1 In the foreword of the laboratory manual2 for the course the purpose is stated as follows: To give an understanding of and a physical feeling for the processes and transport phenomena taking place in la1ge sca le chemical processing equipment. 142 To show how the principles developed during the lectures in unit operations may be u sed in designing and runnin g processing equipment. To furnish insight into how the unit operations used in the chemical industry work and the limitations of these. These purposes have had a large influence on the design of the equipment for the experiments. One might say that the course constitutes a "movement" away from transport phenomena laboratory type equipment. This does not mean, however, that transport phenomena type measure ments (for example, single film heat transfer coefficients as opposed to overall coefficients) are not carried out in the course. Indeed they are, but the tendency is to perform the measurements in process equipment so that the students do not have to extrapolate from model experiments to real life. It is understood that a similar "move ment" is takin g place in several ChE departments in the US. C OU R SE C HA RA CT E RI S TICS The course is offered twice a year in three week periods during which the students devote their full attention to the course. The maximum number of students is 70 per three-week period. Since this is an introductory course, it was found best to expose the students to as many different unit operations as possible For pedagogic reasons it was decided to work with small teams of students (two per team). For these reasons, a relatively large number of experimental units was found necessary. It was also found necessary for the students to work with ready-made experi mental units. If the students were to construct the equipment themselves many of the course CHEMICAL ENGINEERING EDUCATION

PAGE 41

Aage Fredenslund received BS, MS, and PhD ('68) degrees from the University of Wisconsin. He has taught unit operations, transport phenomena, and ChE thermo dynamics at Instituttet for Kemiteknik since 1968. His research interests include high pressure vapor -li quid equilib1 ia, PVT properties of mixtures, and multicom ponent separations. objectives could not be achieved. Later on in the curriculum, the students have a chance of con structing their own equipment during (required) senior thesis work. Altogether 27 experiments have been designed and constructed, and these experiments are di vided into nine groups, each containing three similar (but not identical) experiments. The students must not have more than one experiment from each group. The experimental units are de scribed briefly below. Before each experiment is to be performed, the students are briefed as to the operating con ditions and the report requirements. A variety of possibilities, is built into most experiments. It is found that the students can carry out the experi ments with the aid of the laboratory manual 2 without much further supervision and that they find the experiments quite challenging. The cor rected reports are, of course, discussed with the students, who at the end of the course receive a "pass" or "fail" on the basis of the reports. The laboratory course is housed in two ad jacent localities: an apparatus hall of ceiling height 7 m, containing a small area with ceiling height 16 m, for pilot scale experiments and an ordinary laboratory for bench scale experiments Both locations are provided with ample steam, water, gas, and electrical supply. EXPERIMENTS A short abstract is given for each experiment below. A capital letter in the experiment number SUMMER 1973 (e.g. lA) indicates that the experimental unit is placed in the apparatus hall, and a small letter (e.g. lb) indicates that the experimental unit is located in the ordinary laboratory. 1. FLUID FLOW. Flow of water in pipes. Flow of water in tubing. Flow of air in ducts. 2. FLOW OF FLUIDS THROUGH POROUS MEDIA. Filtration. Fluidization. Flow through packed columns. 3. EVAPORATION AND CONDENSATION. Evapora tion in a vertical tube. Evaporation in a vertical tube. Co nden sation. 4. HEAT EXCH ANGE Heat transf er in pipes. Heat transfer in pipes. Unsteady state heating of water. 5. DISTILLATION. Distillation in a bubble cap column. Simple and batch distillation. Cont inuous distil lation 6. ABSORPTION. Absorption in a packed column. Absorption in a bubble column. Absorption in a sieve tray col umn 7. SIMULTANEOUS HEAT AND MASS TRANSFER. Drying. The wetted wall co lumn. Air humidification in a s pray tower 8. EXTRACTION. Extraction in a rotaing disc co lumn. Extraction in a reciprocating plate column Ex traction in a mixer-settler 9. OTHER UNIT OPERATIONS. Preparative gas chromatography. Reverse osmosis. Crushing and grinding The experiments do not, of course, cover the whole field of unit operation s. The very important area of crys tallization i s for example, omitted. However, they should ensure that the students come in close, practical contact with a broad s pectrum of chemical processing equip ment. REMARKS The experience with the course has generally been good. The students and faculty seem to find the course an interesting worth-while experience. As mentioned above, one argument against a course of this type is that using finished, fixed experimental units does not leave much room for student initiative. However, this was recognized as a danger from the very beginning of the planning, and attempts have been made to make the course as interesting and challenging as pos sible in other ways. Where possible, large scale glass equipment is used so that one may visually observe the phenomena of interest. Adequate in strumentation has been provided so that many tedious measurements are avoided and so that the students may concentrate on the central prob lems ( on the other hand, automation is kept to a minimum as "push-button experiments" are not desired). In addition the fact that most of the experiments are concerned with separation pro cesses, a specialty of chemical engineering, stimu lates interest. (Continued on p. 152) 143

PAGE 42

AN EVOLUTIONARY EXPERIMENT A. MEISEN The Uni v ers i t y of B ri t i sh Columbia Va n cou ver 8, B C., Can a da M ANY CHEMICAL ENGINEERS are involved in the development of industrial processes which consist of several articulated operational steps. Since data for such development are fre quently lacking and are only obtainable through experimentation, the engineer must be capable of devising experimental equipment and procedures. The usual undergraduate laboratory courses do not prepare the engineering student well for such tasks. Most experiments are intended to demonstrate a single rather than a sequence of concepts or operations, and their interdependency, which is so essential for industrial processes, is not apparent. Since the experimental apparatus is usually provided, the student is primarily re quired to follow an established procedure and analyse hi s results. He plays virtually no role in selecting the e x perimental equipment and tech niques. Hence, in order to give students some experi ence with developing a process, an "Evolutionary Experiment" was recently introduced into an ex isting, Senior laboratory course at UBC. The term "evolutionary suggested itself because students worked on the process in turn and it thus evolved during the academic year. The present note de scribes an Evolutionary Experiment on electro winning of copper and emphasizes the organ izational rather than technical aspects. This approach was taken because the latter are thought to be of less general interest. ORGANIZATION The class was divided into groups of three or four students and each worked on the project for two days spaced one week apart. Since only a brief outline of the process was provided and students were required to investigate all major aspects in the course of the academic year, the first group started by making a literature survey. In addition it formulated a detailed work plan and documented its findings in a technical report. Subsequent groups a lwa y s began by reading previous reports and determining their specific 144 Axel Meisen received the BS degree from Imperial College the MS from Caltech and the PhD ('70) from McGill University. His teaching and research interests include air pollution control, proce s s control, and design of undergraduate experiments. objectives commensurate with the general work schedule These decisions were discussed and sometimes modified in a brief meeting with the laboratory instructor before the groups pro ceeded. When experimental equipment had to be built or modified, this could usually be accom plished during the week between laboratory periods. The work of each group concluded with writing a technical report and making recom mendations to future groups. The very last group in the academi c year prepared a summary report. THE PROCESS Due to time limitations, a simple process had to be chosen and electro winning of copper from a leachable ore was selected for the first Evolu tionary Experiment in 1970. This process is quite well understood and consists of three basic opera tional steps: ore leachin g, purification of the leach liquor and electrolysis to yield copper. A further advantage of this process is the production of an important, final product rather than an inter mediate requiring further chemical treatment. The relevancy of this project was therefore clearly apparent to the students. Approximately 300 lbs. of ore were kindly provided by the Anaconda Company from its mine in Weed Heights, Nevada. The ore is readily leachable with dilute sulphuric acid and yields a liquor sufficiently strong for electrowinning. No CHEMICAL ENGINEERING EDUCATION

PAGE 43

The term "evolutionary" suggested itself because students worked on the process in turn and it evolved during the year. special problems of analysis arose since the acid consumption and copper content of the rock or leach liquor could be determined by titration and atomic absorption spectroscopy, respectively. ACHIEVEMENTS Based on the literature survey prepared by the first group, the second group decided that the leaching operation should be conducted by either percolating the acid upward or trickling it down ward through a fixed bed of ore. The important variables were thought to be acid concentration and flow rate. Temperature and rock size could also be varied but were regarded as less signifi cant. The supplied rock was approximately 3 + 5 mesh and was used in this form without further crushing or screening. The second group designed and assembled a simple leaching apparatus whose main compon ent was a 3 in. ID, 2 ft. long glass column con taining the rock. The acid was delivered by a cen trifugal pump from a 10 gallon holding tank through a valve and rotameter to the leaching column from which it returned to the tank. The piping, which consisted of polyethylene, was arranged to permit operation in the percolation and trickle modes. Samples of leach liquor were withdrawn from the holding tank to determine copper content and acidity. Initial tests showed that the liquor flow rate could not be kept constant and it was up to the third group to rectify this problem. Careful ex perimentation revealed that small rock particles became lodged in the valve thus restricting the flow. After several other attempts which proved unsuccessful, a by-pass was installed around the pump. This allowed the valve to be opened more fully and thereby reduced the chance of blockage. The subsequent three groups studied the leach ing rate as a function of acid concentration, flow rate and mode of operation. By applying Leven spiel's tests1, the results were found to be repre sentable by the unreacted-core model with the major resistance to mass transfer lying in the leached, outer layer of the rock particles. Hence varying the flow rate and operational mode did not significantly affect the leaching rate. The acid consumption was almost stoichiometric with re spect to copper indicating that few other rock constituents were attacked. SUMMER 1973 The sixth group was originally scheduled to investigate purification of the leach liquor neces sary for electrolysis. However, since the iron and particulate content of this liquor were unex pectedly low, the group concentrated on design ing an electrolytic cell and washing the leached rock. The latter ensued from the realization that copper sulphate adhering to the rock constituted an economic loss and environmental hazard if discharged. Washing with water was shown to be complete in less than one hour. The electrolytic cell consisted of a 3 in. by 5 in. lead anode and similar copper cathode situated in a rectangular, plastic tank. The spacing of the electrodes was variable and the leach liquor was continuously passed between them by letting it overflow the anode and discharge through the bottom of the cell. Poor liquor distribution re sulted and the evolution of gas bubbles interfered with the electrolysis. These problems were re solved by the seventh group which modified the cell by introducing the electrolyte at the bottom and forcing it to flow upwards between the elec trodes. The effects of flow rate, electrode spacing and current density on copper deposition were in vestigated and current efficiencies in excess of 90 % were achieved. The final group prepared a summary report and indicated areas requiring further work. Furthermore, it considered the problems asso ciated with scale-up of the laboratory data. STUDENT REACTION Student response to the Evolutionary Experi ment was quite favourable because it provided a break from the more traditional laboratory work. They enjoyed the flexibility of the project and the ability to formulate their own objectives. Since each group started where the previous one had left off, the work seemed more original than usual. Finally, students appreciated the oppor tunity to study an industrially significant process and gain practical experience with developing ex perimental equipment. Since each group worked on a different aspect of the Evolutionary Experiment, students recog nized the necessity for clear and concise technical reports. Needless to say, they were not overjoyed by this realization, but it made the task easier. (Continued on p. 147) 145

PAGE 44

A FORCED CONVECTION DEMONSTRATION USING SOLID CO2 SUBLIMATION D. A. MELLICHAMP and 0. C SANDALL University of California Santa Barbara, CA 93106 One of the features of the transport processes sequence presently taught to chemical engineer ing undergraduate students at UCSB is the weekly laboratory which is used to illustrate selected principles from the lectures. Experi ments performed during the laboratory period usually take the form of a demonstration where data are taken to be analyzed by the students in an assigned home problem. In this way many of the home problems cover a practical transport problem involving the analysis of real data. The department sub-sonic wind tunnel is used for the majority of these demonstrations. Hence, in the fluid dynamics course the demonstrations start with simple air stream velocity measure ments, cover the standard demonstrations of drag on a bluff object, boundary layers, etc. In the course on heat transport, demonstrations cover such topics as heat transfer from a cylinder in transverse air flow. In the concluding course dealing with an alogous mass transport phenomena, the difficul ties encountered in designing appropriate demon strations are significantly greater. The authors, in a recent paper1, described an experiment de veloped by students as a term project which covers mass transfer from a cylinder in trans verse air flow. In this experiment the cylinder is cast from naphthalene with a liquid nitrogen quench to obtain a very fine grain structure at the surface of the cylinder The low sublimation rate of naphthalene, even under conditions of forced convection, requires running times in the wind tunnel on the order of a full day -to achieve measurable material loss from the cylinder. The advantage of the naphthalene cylinder experi ment, however, is that simple mechanical methods can be used to measure accurate l y the rates of mass transfer. These data can then be compared to analogous data from heat transfer experi ments. 146 Obviously this experiment requires too much time to serve as an effective demonstration. Con sequently, we have developed a complementary experiment, utilizing a dry ice cylinder, to furnish a rapid visual demonstration of mass transfer in transverse air flow. Solidified carbon dioxide has a much higher vapor pressure than most common solids; hence, with a vastly increased driving force for mass transfer, wind tunnel demonstra tions can be run in several minutes. A further advantage of the use of a dry ice cylinder is that normally there is enough moisture in the ambient air which condenses in the vicinity of the cylinder to provide effective visual evidence of boundary layer formation and separation, vortexing in the cylinder wake, and the flow patterns in the vicin ity of the rear stagnation point. The experiment is quite simple to carry out. A mount (shown in the accompanying figure) supports the cylinder in the wind tunnel test sec tion The mount is adjusted to hold the cylinder Figure 1 Dry Ice Cylinder Mounted in Wind Tunnel CHEMICAL EN G INEERIN G EDUCATION

PAGE 45

Orville C. Sanda11 is currently an assistant professor in Chemical Engineering at the University of California at Santa Barbara. He obtained his education at the Uni versity of Alberta (BSc, MSc) and the University of Cali fornia at Berkeley (PhD). His teaching and research in terests are in the areas of heat and mass transfer. (left). Duncan A. Mellichamp is an assistant professor in Chemical Engineering at the University of California at Santa Barbara. He received the BChE at Georgia Tech, studied one year at the Technisch e Hochschule Stuttgart (Germany), and obtained the PhD at Purdue University. His present interests are in the fields of process dynamics and automatic control. (right). in compression with dense foam rubber (in our case, rubber backed carpeting) gaskets used to insulate the cylinder from the mount and to maintain the compressive force as the ends of the cylinder sublime. Preparation of the cylinder is very simple, if somewhat novel. An ordinary three pound block of dry ice is set -up in our ma chine shop metal lathe. It is quickly turned to the required diameter by standard machining techniques and immedi ately brought to the wind tunnel for the demonstration. After mounting the dry ice cylinder in the wind tunnel the air flow is turned on and is quickly adjusted to correspond to the desired Reynolds number. It was found that at prevailing air relative humidities of approximately 50 % the streamline patterns of condensed moisture were clearly visib le at air velocities of approximately 50 ft. / sec. For the 2-inch diameter cylinders used in the demonstration, this corresponds to a Rey nolds number of about 50,000. At this Reynolds number the laminar boundary layer separates before it becomes turbulent, the point of separa tion occurring at an angle of about 80 degrees from the forward stagnation point. The stream line patterns clearly show the separation point and the angle of separation is easily estimated by the students to be at approximately 80 degrees SUMMER 1973 The department sub-sonic wind tunnel is used for demonstrations in fluid mechanics and heat and mass transport phenomena fro mthe forward stagnation point. The stream lines in the downstream turbulent wake are also clearly visible particularly near the rear stagna tion point. After running the demonstration for about five minutes the wind tunnel is turned off and the dry ice cylinder may be inspected. This length of time is sufficient for a protruding ridge to appear at the separation point. This ridge indicates the sharp minimum in the local mass transfer co efficient that occurs at the point of boundary layer separation REFERENCE 1. Sandall, 0. C and Mellichamp, D. A., "A Simple Forced Convection Experiment", C hemi. Engi. Edu. Vol. 5, 134-136 (1971) MEISEN: (Continued from p 145) Report writing was further simplified by the fact that students did not primarily write for the in structor but rather for their class-mates whose technical competence they knew. CONCLUDING REMARKS Although it is clear that not all undergraduate experiments should be replaced by Evolutionary Experiments, the addition of one or two can con siderably enliven a laboratory course. In order to maintain student interest, the topics should be frequently changed. The following projects, which have either been conducted or are planned at U.B.C., may serve as further examples of Evolu tionary Experiments: production of crystalline copper sulphate from an Arizona ore, extraction of protein from fish meal, manufacture of fur furaldehyde from sawdust and recovery of metals from scrap tin cans. The latter two projects were initiated by Dr. K. B. Mathur and Dr. A. P. Watkinson, respective ly REFERENCE 1. 0. Levenspiel, Chemical Reaction Engineering, p. 338, John Wiley and Sons, New York, 1962. 147

PAGE 46

AN INTEGRATED REACTOR ENGINEERING LABORATORY R. D. WILLIAMS University of Arizona Tucson, AZ 85721 Chemical Engineering is unique among other engineering specialties in that its basis is in chemistry. Since this is so and since chemical rate phenomena are an important part of chem istry, the body of knowledge including not only chemical rate phenomena but also the coupling of such phenomena with physical processes is worthy of intensive coverage in the training of chemical engineers. Two pressures familiar to academicians in volved in curricula review are the pressures from outside the University (industry) to make the curriculum more relevant and practical, and pres sures from inside the university to make the curriculum attractive to interested students. These two pressures are not complementary in that the former results in the addition of new experiments or new laboratories and hence -~ends to increase the rigor of the curriculum whereas the latter results in just the opposite. At the University of Arizona we have at tempted to compromise these considerations in the area of chemical reaction engineering by integrating as much as possible of relevant prin ciples, concepts, and techniques from the theory course into a one unit laboratory in the semester following the presentation of the theory. As will be brought out, the number of items deemed im portant for inclusion into the lab necessitates careful selection of experiments such that each covers several of these important items. It is in this sense that the term "integration" is used in this paper and not in the sense that the theory and lab have been integrated time-wise. This paper will first discuss laboratory objectives and then illustrate their implementation by giving specific examples of experiments being conducted. OBJECTIVES In 1969 we conducted a poll of 152 departments of c hemical engineering, principally in the United States 148 a nd Canada. The response 1 to the poll was high (102 / 152= 67 % ) so that meaningful conclusions may be drawn as to trends across the country. Of the 102 responding de partment s, 61 s t a ted that they currently had some lab exper i e nce in kinetics and 41 did not. Of those who did, only 8 h ad labs completely devoted to the subject and of those who did not the majority (33 / 41) anticipated the addition of such exper ience in the future The r esp onding departments indicated that their most popular experiments utilized single phase systems in batch, CSTR, and tubular reactors. Almost as popular was the heterogeneous catalytic type of reaction conducted in a diff ere ntial tubular reactor with analysis by gas chromatography. From this it may be deduced that the demonstration of r ea ctor behavior with simple (single phase) systems is generally of highest priority and that to illustrate mo re complex (heterogeneous) systems the differential reactor is being used, presumably due to its simplicity, ease of analysis, adaptability and compatibil ity with gas chromatography. The objectives selected for our laboratory are: To complement the theory course with practical ex perience. To provide a variety of experience in reactor types, typ es of reacting systems, methods of data collection, methods of data analysis. To provide a labo r atory environment in which some degree of success is assured. The specific experience areas from the theory course which were desirable for the laboratory were: 1. Reactor types. A. Batch. Homogeneous (isothermal, adiabatic). h ete rogeneous slurry. B. Continuous s tirred tank. C. Continuous integral tubular. D. Continuous differential tubular 2. Reacting Systems Types. A. Homo ge neous. B. Hete r ogeneous catalytic. C. Heterogeneous noncatalytic. 3. Data Collection Methods. A. Direct mte monitoring. Titration. Gas chroma tog ra phy Optical measurement. B. Indirect rate monitoring. Temperature meas urement. Pressure measurement. 4. Data Analysis Methods A. Integral method. B. Differential m e thod. CHEMICAL ENGINEERING EDUCATION

PAGE 47

Richard D. Williams has been at the University of Arizona since 1968. He studied at Texas Tech University (BS) and obtained his doctorate in Chemical Engineering at Princeton University. His current area of specializa tion is chemical reaction engineering The experiments which have been run using homogeneous systems are listed below. Each of these four experiments is run by all the student groups and collectively they occupy about one-half to two-thirds of the course: 1. Batch kinetics determination by direct sampling. 2. Prediction and experimental verification of single and multiple CSTR performance. 3. Prediction and experimental verification of packed and unpacked tubular behavior 4. Batch kinetics by an indirect m e thod-the adiaba tic reactor. The heterogeneous experiments which have been implemented are given below. Each student group will take one of these experiments as an independent project for the time remaining at the end of the semester. 1. Hydrogenation of nitrobenzene on Pd-charcoal in a slurry reactor, with indirect pressure measure ment. 2. Dehydrogenation and dehydration of IP A on Ptcharcoal in a continuous microreactor, analysis by gas chromatograph. 3. Noncatalytic TCC catalyst regeneration. Each of the experiments will now be briefly discussed giving its advantages to the l a b. EXPERIMENTS-HOMOGENEOUS The first experiment involves the verification of a postulated reaction order and determination of rate constant temperature dependence for a homogeneous reaction in a batch reactor. To date we have used the ethyl acetate saponification re action. Figure 1 is a schematic of the experi mental apparatus which consists of a constant SUMMER 1973 F i g. 1. Reactor Bench temperature bath and a three liter glass-stainless steel re a ctor. Data is typically collected by direct sampling and titration. The methods of excess and / or half-lives may be used but in any case an integral method is used for data analysis. Our experience indicates that many students lack sufficient lab technique to get good results with this experiment. In accord with our objective of providing an environment to insure some success and especially in light of time limitations we are considering changing this experiment (and the two to follow) to automate the analytical tech nique. The second experiment has been the experi mental study of the transient startup of a CSTR sequence. Figure 2 illustrates our reactor bench in more detail. Reactants are contained in -~wo pressurized 5-gallon polyethelyene carboys .':l.nd are passed through coils in the constant temper ature bath before being metered into the continu ous reactor being studied. The experimental re sults may be checked against theory by using the reaction rate expression developed in Experi ment 1. Degrees of non-ideality may be controlled by changing mixing RPM, reactor baffling and nearness of inlet and outlet ports. Fig. 2. Reactor Bench Detail 149

PAGE 48

The third experiment uses the same feed system as Experiment 1 but in conjunction with a jacketed glass tubular r eactor. In this experi m e nt s teady state conversion is obtained as a function of mean residence time for both an open tube and with the tube packed with 1 / 4" glass Raschig rings. These first three experiments all conducted on the same reactor bench serve to give the student a better understanding of how mixing in a chemical reactor determines reactor behavior. Other experiments which could be run on this very adaptable apparatus include resi dence time distribution determinations and demonstration of steady state multiplicity. These experiments are currently being prepared for future use. The last homogeneous experiment run was chosen for several reasons. It demonstrates th e operation of an adiabatic batch reactor with an exothermic reaction. Unlike the isothermal ex periments which precede it, this experiment re quires that an energy balance be made for data analysis Further, since the coupled material and energy balances are nonlinear the integral method of analysis will not work. Fortunately, the differ ential method comes to the rescue and is fairly accurate since the continuous temperature-time trace may be easily differentiated. The reaction used is that between hydrogen peroxide and sod ium thiosulfate and unlike the ethyl acetate saponification reaction it has a nonobvious stoi chiometry which may be experimentally de te mined. Figure 3 is a schematic of the experi mental arrangement. ML BEAKER fig 3. Apparatus for the Adiabatic Reactor In a typical experiment the reactants are mixed together and the sigmoidal temperature increase with time is recorded. The temperature rise will depend on the volume of the reaction mixture and the amount of limiting reactant present. If the volume is held constant (at 400 cc for example) and the initial reactant ratio is 150 /'; T 8J 70 00 c'Cl 50 30 20 JO (!] N.<#3 + I NAM, + 3N.<#3+411t)i= 2~+2rw:tl+311jl N.<#3 + 411t)i+rw:tl 2f+511jl 3N.<#3 + Sllt)i NA:?5,f\;+2f+511f) (!l NAM + 4 f NA:?53% + NAiIJ4 + 4 llfl 'low-~ 2Mf /'low-~ 2MN.<#3 fi{I 4 Temperature Rise as a Function of Initial Reactant Ratio varied then the temperature rise will go through a maximum when the initial reactant ratio is equal to the stoichiometric ratio. This is shown in Figure 4 with student data from last year. The different symbols correspond to different student groups. From this graph it appears that of the possible stoichiometrys listed, the appropriate one is the last equation listed. Theoretically, it can be shown that if the rate of temperature change divided by the approach to the final tem perature squared is plotted against reciprocal temperature an Arrhenius plot results (Figure 5). The experimental activation energy found using student data compares very well with that 1o ~r ~ -~-~-~--,--....--.---.---.--,---, EEXP = 18 .7 KCAL./ G'OLE 102 ~IT= 18,28 0,3 KCAUG'OLE [!I 103 104 3,0 3 .1 3.2 3.3 3 4 lCXXl/T ( O K) 1 CHEMICAL ENGINEERING EDUCATION

PAGE 49

reported in the literature as shown Table 1 gives a more comp lete list of experimental values ob tained from student data compared with litera ture values. The agreement is quite good. TABLE 1 COMPARISON OF STUDENT }\;;D LITERATURE VALU ES kca;: ; ~~le k o E liters / mole V A/ V B ~~a 2S203 k cal /mole sec Student 142 7 18. 7 7 33 X 10 11 Literature 142.S 18 28 .3 6.85 X 10 11 EXPERIMENTS-HETEROGENEOUS The remainder of the experiments utilize heterogeneous systems and each student group will work with just one of these for the rest of the semester. An apparatus used to study the catalytic de composition of isopropyl alcohol (IPA) is shown in Figure 6. Helium carrier gas is bubbled through He IPA Fig. 6 Microreactor IPA dehydrogeneration and dehydration. the IP A and then passes through a microreactor containing Pt-charcoal catalyst. The reactor efflu ent may be sampled and analyzed by gas chroma tograph. IP A will decompose to give either pro pylene and water or acetone and hydrogen de pending on reactor conditions, particularly tem perature. The temperature of the reactor is main tained by a sandbath and sampling is accom plished with a multiport sampling valve. This is an easy experiment to run and demonstrates well the reaction selectivity dependence on tempera ture, the use of a differential reactor for obtain ing initial rate data and the use of a gas chrom atograph for analysis. The apparatus is very flexible in that various different reactions and catalysts may be used. Another good example of a heterogeneous sys tem is the hydrogenation of nitrobenzene over SUMMER 1973 Fig 7. Slurry Reactor Hydrogenation of Nitrobenzene. Pd-charcoal catalyst in a s lu rry reactor such as depicted in Figure 7. We use a one liter Parr autoclave with a gas storage volume and mercury manometer though the experiment can be just as well studied in glass as reaction pressures are not high. Nitrobenzene and catalyst are charged to the reactor before assembly. The air space over the nitrobenzene is flushed with nitrogen and then with hydrogen before pressurizing the sys tem with hydrogen by reference to the mano meter. To initiate the reaction, agitation is begun, dispersing the hydrogen and catalyst into the nitrobenzene. Hydrogen pressure is recorded as a function of time from which reaction rate may 0 15 0 .1 0 LN ( P /Pl 0 05 0. 0 o 10 5aJ RPr1 CA T ALYS T L O ADIN G 0 236IJ GRAMS 0 .5' ))'.) GRAMS 1iJ l, 25llJ GRAMS 20 T lr'c (M I N ) 30 Fig 8 Pressure ratio verses time and catalyst loading for nitro benzene 1 8 hydrogenation. 151

PAGE 50

0,15 0.10 3 10 Ul (PJ P ) 0.05 0,0 10 20 T1ME (rJN,) Fig 9. Pressure ratio verses time and mixing rate for nitrobenzene hydrogenation. be calculated. Theoretically the expected behavior is first order with the effective reaction rate con stant being dependent on temperature, agitation rate, and catylyst loading. Figures 8 : md 9 illus trate the type of data which is obtained. The first order behavior is verified and rate constant de pendence on catalyst loading and agitation rate is shown. Figure 10 summarized the results of Figure 9, giving the reaction rate constant as a function of mixer RPM. The high RPM asymp tote corresponds to chemical reaction rate control and the low RPM asymptote results from a dif fusion controlled regime. Data at temperatures other than room tempe rature would allow for the determination of the activation energy and pre exponential factor of the chemical reaction rate constant. Empirical correlations for catalyst loadFREDENSLUND: (From page 143) The stated course objectives appear to have been met satisfactorily, although improvements in the course are still being-and will continue to be-made. Before starting the design of a course of this type, the purpose of the course must be very clear, since the equipment design may vary a great deal with the objectives. These objectives are likely to differ somewhat from department to department. 152 300 250 200 1/(X ( MIN,) 150 100 50 0 200 500 CATALYST LOADI I-Xi 0 5 GRA"lS 750 l'.Ul 1250 W M 1500 Fig. 1. Effective rate constant verses mixing rate for nitrobenzene hydrogenation ing and RPM (or mixing power input) are also possible alternatives. Other heterogeneous experiments which are currently under development include the high temperature, noncatalytic regeneration of coked Thermofor catalytic cracking catalyst and the leach recovery of metals (e.g. copper) from their ores. ACKNOWLEDGMENT In developin g such a laboratory one should be alert for experiments which others have developed which have proven to be successful and which complement the lab oratory objective. In thi s 1egard, I must acknowledge the use of ideas of Dr s. James B Ander so n at Yale and Gordon B. Youngquist of Clarkson They have been espe cially helpful in suggesting experiments which we hav e used s uc cessf ully. ACKNOWLEDGEMENTS Th e author w i s he s to thank all c olleagues in Lyngby Lund, and Trondh e im, who h ave co ntribut e d to the d e velopment of the course. REFERENCES 1. C rosby E. J. "Ex p er im e nts in Tran sport Phe moment" Wi ley, N ew York, 1961. 2 Fr ede nslund, Aage, "Experiments i n Unit Opera tion s" Den p r ivat e Ing e niofond, Copenhagen, 1972 (27 0 pp. in Dani s h ) CHEMICAL ENGINEERING EDUCATION

PAGE 51

Hes locked into childhood by a disease thatS already licked. What happened was measles Common measles. And what s tragic is that it should never have happened at all. To most people, measles is simply a childhood nuisance But statistics don t bear them our. During the height of the me sles season, 10,000 children are stricken every three days. 60 a re hospitalized 10 develop inflamma tion of the brain, 3 become men tally retarded And one dies. There 's just no excuse for chi s disastrous waste Since 1965, the measles vaccine developed by Dow has more than proved its worth. And the cost of immunizati o n is low compared to the consequences of the disease, the staggering expenditure in medical care a nd the enormous number of school days missed But after several years of dra matic decline, measles is now ga loping back Because even the best preventive is powerless if peo ple refuse to use it The answer is nor more of our vaccine. There s already plenty of that. It s community awareness of the threat measles poses to our children. And community action ro stop the disease in its tracks. At Dow, we re concerned with more than chemistry We re con cerned with life And despite our imperfections, we re determined ro share its promise Wisely For a booklet on measles vac cination and your children, write co : The Dow Chemical Company, Midland, Michigan 48640. .. J

PAGE 52

HOWTO MAKE YOUR FUTURE OUT OF PAPER. Paper. You might think it's almost too simple to be interesting: News papers, napkins, towels, cups. Simple. But have you heard about the paper that's used as the core of high-impact plastic laminates? Or the pre-lubri cated communication paper tape for data-processing equipment? Or the specialty papers with complex coat ings for keeping packaged foods fresh? Or the 3-ply paperboard made with polyethylene film, virgin pulp and recycled pulp which together create an excellent moisture barrier? And did you know about our chemical products that are used in environmental systems for air and water purification? Or our specialty chemicals used to make products in almost any industry you name? And about the research involved in all this? The physical, organic and in organic chemistry? The physics, math ematics and biology? The mechanical, chemical and electrical engineering? At Westvaco, making paper is a whole lot more than just making paper. And that's why we're interested in innovative, naturally curious people who can see the future in paper the way we do. With them, we think we can help shape the future for everyone. Westvaco 299ParkAvenue New York, N Y.10017 An Equal Opportunity Employer