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:
serial ( sobekcm )
periodical ( marcgt )

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

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WE ENCOURAGE JOB HOPPING.
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learn more and you learn faster.


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* know, the stronger we are. Now-you want to
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for a copy of our Career Guide. SUN OIL
COMPANY, Human Resources Dept. CED.
1608 Walnut Street, Philadelphia, Pa. 19103.


An Equal Opportunity Employer M/F









EDITORIAL AND BUSINESS ADDRESS
Department of Chemical Engineering
University of Florida
Gainesville, Florida 32611

Editor: Ray Fahien
Associate Editor: Mack Tyner
Business Manager: R. B. Bennett
(904) 392-0881

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University of California, Santa Barbara


Chemical Engineering Education
VOLUME IX NUMBER 1 WINTER 1975



FEATURES

40 4wa4d .etede 197
Biotechnology-An Old Solution to
New Problems, E. Gaden


DEPARTMENTS
2 The Educator
Bruce Finlayson of U. of Washington

4 Departments of Chemical Engineering
University of Waterloo

32 Classroom
An Introductory Design Course for
Engineering Freshmen, G. Younquist

8 Views and Opinions
Some Comments on ChE Laboratory
Courses, J. M. Douglas

31 Book Review

31 News

Laboratory
10 Flow Curve Determination for Non-
Newtonian Fluids,
W. Walawender and T. Chen

16 Teaching Process Synthesis, K. Overholser,
C. Woltz and T. Godbold

22 Preliminary Appraisal of a Self Paced
Laboratory, H. Rase

24 Reporting Precision of Experiments
K. Hall, D. Kirwan and 0. Updike

28 Some Simple Experiments for First Year
Students, A. Gerrard


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 32611. 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 1975. 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.


FALL 1974









educator :


OF UNIVERSITY OF WASHINGTON

OF UNIVERSITY OF WASHINGTON


Bruce has developed an enviable reputation as a
teacher.

C. A. SLEICHER
University of Washington
Seattle, Washington 98195

N OW IT CAN BE REVEALED. There really
is an Okie-from-Muskogee in our midst!
Bruce Finlayson-musician, hiker, sailor, skier,
plumber, carpenter, committee chairman, hus-
band, father, chemical engineer, talented research-
er, dedicated teacher-grew up in Muskogee,
went to high school in Muskogee, played in the
Muskogee High School band. Indeed, his interest
in the band (He was a drummer), was to alter
the course of his life. From high school he went to
Rice University, joined the band, and there met
a lovely lyre player, Pat Hills. That in turn led to
Mark, aged 10; Catherine, aged 8; Chris, aged 6;
and numerous other manifestations, great and
small.
Bruce worked his way through Rice by
scholarships, by playing in a dance band, and by
waiting on the training table. He also worked
summers, and on employment applications de-
scribed his occupation as "unemployed waiter."
The relation between this description and the


summer jobs he took is obscure; he sold pots and
pans, was a gas station attendant, and taught
goat lassoing on a dude ranch. Now, it is comfort-
ing to think that this last experience stimulated
his interest in the noble profession of teaching,
but to tell the truth it was quite irrelevant. In
reality his interest in teaching developed by acci-
dent. We return to the band and Pat.

A FATEFUL YEAR

AT RICE, BRUCE WAS in the N.R.O.T.C.,
which forbade getting married before getting
a commission at the end of a five-year program.
That proved too long for Bruce and Pat, so he
was commissioned after four years, took an im-
mediate leave of absence from the Navy, got
married, and stayed at Rice to complete a Master's
degree program in his fifth year. That year proved
to be a fateful one; while working on his thesis
on nucleate boiling, he became interested in teach-
ing and research and decided once again to post-
pone his Navy duty and continue graduate study
instead. The next year he enrolled in the graduate
program at the University of Minnesota, where he
worked on a Ph.D. program under Professor L. E.
(Skip) Scriven, a demanding but stimulating ex-
perience. His studies of the essential differences
between true variational principles and quasi and
ad hoc ones were published in a series of papers
with Skip Scriven. This led to a unity of viewing
approximation methods for solving differential


The bulk of his research is in
applied math but he is committed to
studies that have application, and many
of his students do experimental work.
His studies of variational and
approximate methods were collected in a
book which appeared in 1972 amid
numerous favorable reviews.


CHEMICAL ENGINEERING EDUCATION









January 1974. Some of his current research
centers on extending some of the ideas in the book
to more than one dimension. Bruce believes that
the method of orthogonal collocation on finite ele-
ments may greatly reduce the machine computa-
tion time required for two- and three-dimensional,
non-linear problems, and he has begun to test out
these ideas in the field of petroleum reservoir
calculations.


TEACHING REPUTATION
T HOUGH WIDELY RECOGNIZED for his
research, Bruce has developed an enviable
reputation as a teacher. He enjoys teaching and
acquires a sense of excitement as each quarter
approaches and new classes begin. He keeps his
office door open; there is no buffer between him
and students. The students in turn regard him
not only as a helpful teacher but a stimulating,
innovative one as well. Together with Professor
Norman Sather, he has developed self-paced ma-
terial for the teaching of mass and energy


S* Bruce bicycles to work
-rain or shine.







equations of fluid mechanics and heat and mass
transfer which Bruce then applied to an investiga-
tion of the motion of certain fluids having a non-
symmetric stress tensor. After completing his
graduate studies at Minnesota, he embarked on a
two-year period of duty with the Navy in Wash-
ington, D. C.
In 1967 Bruce and his growing family moved
to Seattle, where Bruce joined the Chemical En-
gineering Department at the University of Wash-
ington. In the seven short years he has been here,
he has developed a research program that has
achieved national and international repute. The
bulk of his research is in applied mathematics,
but he is committed to studies that have applica-
tion, and in consequence many of his students do
experimental work. His current experimental
work is on the effects of magnetic fields on liquid
crystals and on flow properties in radial flow re-
actors. In the applied mathematics area he began
to apply approximate methods to model chemical
reactors, axial dispersion in packed beds, and
catalytic mufflers. This work made use of the
method of orthogonal collocation, some of it
applied to three-dimensional, transient situations,
and recently he was asked to write a review paper
on orthogonal collocation in chemical reaction
engineering (Cat. Rev.-Sci.-Eng., 10, 69-138,
1974).
Bruce's studies of variational and approximate
methods were collected (and extended) in a book,
"The Method of Weighted Residuals and Varia-
tional Principles," which appeared in 1972 amid
numerous favorable reviews. One result of the
publication of the book was an invitation to be
an invited speaker at the International Sym-
posium of Finite Element Methods in Flow Prob-
lems, held at University of Swansea, Wales in


Bruce enjoys backpacking with his family in the
Cascade and Olympic Mountains.

balances and chemical thermodynamics, which
are the first two courses in the under-graduate
chemical engineering curriculum. The students
find these courses to be a unique and valuable
learning experience. Students particularly like
the personal assistance given to those who need
it and the healthy exchange of ideas that occurs
as students develop their own approaches to a
problem.

(Continued on page 23.)


WINTER 1975








[9j department


WATERLOO


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M. MOO-YOUNG
University of Waterloo
Waterloo, Ontario, Canada
THE UNIVERSITY OF WATERLOO came
into being in 1957, and after some birth
pains, announced its intention to be the first
Canadian university to undertake cooperative
education in engineering and other professional
programs. Significantly, the first building con-
structed was the Chemistry and Chemical
Enginering building. Because the concept of co-
operative engineering education was new in
Canada (although old and well tested in Europe
and the U. S. A.), the faculty members first at-
tracted to the new-born institution were a group
devoted to educational innovation. Indeed, the first
Chairman of Chemical Engineering, T. L. (Ted)


Batke, went on a few years later to become Aca-
demic Vice-President of the University, in which
post he served during its early development.
The unprecedented growth of the University
in its first decade was due almost entirely to the
immense success of the cooperative programs and
to their complete acceptance and support by
Canadian industry. By 1970 the University of
Waterloo had the largest undergraduate engineer-
ing school in Canada, and the second largest
graduate school. In emulation of our success, two
other Canadian Universities have since started
cooperative engineering programs.
The growth in engineering at Waterloo was
paralleled by the growth in applied mathematics
and computer science, in which cooperative pro-
grams were also initiated. A large part of the


CHEMICAL ENGINEERING EDUCATION


4
V4



is


II


*ANA&.










The unprecedented growth of the university was due almost entirely to the immense success of the
cooperative programs and to their acceptance and support by Canadian industry. By 1970 we had the largest
undergraduate engineering school in Canada, and the second largest graduate school.


strength of the University is still founded in these
two areas, with about 50 % of the total enrollment
of 13,000 students being in them.

GROWTH AND PLANNING
G IVEN A NEW ENGINEERING school sup-
ported with soaring enrollment and generous
government aid, the atmosphere of the early days
was "Gung-ho!" and the Department grew to its
present form and size in barely 14 years.
In 1962 Batke left the Department to serve as
Vice-President of the University and L. E. (Lou)
Bodnar became acting Chairman. In 1964 D. S.
(Don) Scott was appointed Chairman. The rapid
growth at this time meant that some long-range
objectives needed to be formulated. The basic
organization into discipline-oriented and industry-
oriented areas (described later) was set up and
future growth was directed towards developing
excellence in them.
During this period some Departmental "sacred
cows" in educational philosophy also evolved: no
more than two courses per semester as an average
teaching load; no more than about 20 contact
hours per week for undergraduates; no teaching
or research area should be started or maintained
unless at least 3 full-time faculty members were
primarily devoted to it; about 10% of the teach-
ing salary budget for visiting professors; student
representation on all curriculum-related com-
mittees. Our basic organization remains the same
today but with some modifications including the
introduction of essential business-oriented and en-
vironmental courses.
In 1970, K. F. (Ken) O'Driscoll came from
S. U. N. Y. (Buffalo) to assume the Chairman's
post. At about this time, in common with the
general North American scene, the University
entered a period of more limited growth. "Ma-
turity" has crept up on the Department and life
is more stable now. The pursuit of excellence in
teaching and research is a long task and as we
enter maturity, we feel that we are well on the
way. Our family has become large, probably the
largest of the 19 Canadian ChE families. The


present level of activity includes 400 under-
graduates and 80 postgraduates, including post-
doctorals, and 28 full-time faculty members.

UNDERGRADUATE PROGRAMS
At Waterloo, the undergraduate programs are
designed to teach students that responsible
engineers are involved not only with the tradition-
al role of providing material needs but also with
the quality of life which is affected by the creation
of their processes and products. Since chemical
engineers can contribute to the solutions of cur-
rent world problems in health, nutrition and pollu-
tion, relevant course material has been built into
the programs and the curriculum is constantly
under revision to meet changing needs.


Prof. Turner (right) with specially designed equipment for measuring
thermal properties discussed in his recent book.

A basic education appropriate for a variety
of careers is stressed. Our graduates may go di-
rectly into jobs, continue with further studies in
Science or Engineering, or as many have done,
enter other professions such as Medicine and Law.
In the early years, chemistry, physics and mathe-
matics form the usual foundation. Later, subjects
such as economic analysis, design, and entre-
;preneurship enable the student to reach a
practical appreciation of his earlier studies.


WINTER 1975








Specialization is available through six options:
(1) Biochemical and Food Engineering (2) Ex-
tractive and Process Metallurgy (3) Pollution
Control Engineering (4) Polymer Science and
Engineering (5) Transport Processes (6) Mathe-
matical Analysis and Control.
At present about one-quarter of the curricu-
lum consists of elective courses, both technical and
non-technical. Three of the technical electives are
selected from one of the six options.
Student-faculty contact outside of lectures is
facilitated by frequent get-togethers organized
-__W1,.' .&. _,3 '7 ...= -LW t_ _-_ -I


View of Engineering Complex (floor space 477,035 sq. ft.), ChE
Dept is T-shaped section in foreground (floor space 124,626 sq. ft.).
by the Chem. Eng. Club, the Waterloo student-
chapter of the C. S. Ch. E. Each class has a class-
professor who looks after the general well-being
of each student. Class professors handle academic
as well as non-academic problems, usually by
referral services, e.g. Counselling, Health Services,
course-tutors, banks. This particular student-
professor relationship is especially helpful to the
first-year students. Another, probably unique
feature is the final-year study-room which is
"home" in the department for all seniors. Each
has his own desk and facilities are available for
coffee, magazines, calculators, etc.

CO-OPERATIVE EDUCATION
T HE PREPARATION FOR AN engineering
career normally involves formal academic
studies followed by practical experience. The co-
operative education system at Waterloo provides
an integrated pattern of both academic study and
practical experience for the undergraduate. The
degree program covers almost 5 calendar years,
comprising eight 4-month terms of academic
training, alternating with six 4-month terms of
practical training which brings a student into di-
rect contact with the engineering profession.


The cooperative system provides the student
engineer with a career perspective and the op-
portunity to secure financial assistance. Work-
term jobs are found and supervised by the Uni-
versity Co-ordination Department, which ar-
ranges on-campus interviews and maintains a
staff throughout the country to arrange on-site
details with the over 700 participating companies
and agencies. Undoubtedly, the success of this
program is largely due to the efficient organiza-
tion of our Co-ordination Department.
GRADUATE AND RESEARCH PROGRAMS
THE DEPARTMENT OFFERS postgraduate
programs leading to the M.A.Sc. and Ph.D.
degrees. The minimum credit requirements for
the M.A.Sc. are 4 courses and a research thesis,
or 8 courses and a design project; for the Ph.D.,
4 courses and a research thesis. As with other
Canadian programs, these requirements represent
a compromise between the British and American
formats.
While the undergraduate programs are all
based on the co-operative education system, al-
most all the postgraduate programs are not. How-
ever, special arrangements are made for part-time
and off-campus studies, which are encouraged for
the continuing education of engineers. At present,
in addition to on-campus evening lectures, off-
campus classes are given in two locations: Sarnia,
Canada's largest chemical industrial complex;
and Sheridan Park, the largest industrial research
community in Ontario.
Research at Waterloo is currently organized
into five groups. Faculty members associate with
these groups voluntarily; some members belong to
more than one group and occasionally some change
their group affiliation as interests change. The


Prof. Fahidy (left) tutors on the finer points of computer applications.


CHEMICAL ENGINEERING EDUCATION




























Prof. Moo-Young (center) and research assistants with fermentor
which helped to bring biochemical engineering fame to Waterloo.

groups exist to co-ordinate course offerings and
to optimize the use of equipment, space and
graduate-recruiting facilities. The current areas
of research are shown below.

BIOCHEMICAL AND FOOD ENGINEERING GROUP
Mass transfer, heat transfer, mixing, cell-growth and
enzyme kinetics in biotechnology. Design of fermentation,
food processing and waste treatment facilities. Hydro-
carbon and cellulose fermentations, food rheology, micro-
bial proteins, immobilized enzymes, manure utilization.
(Moo-Young, Robinson, Scharer, Silveston, O'Driscoll)

EXTRACTIVE AND PROCESS METALLURGY GROUP
Pyrometallurgical, hydrometallurgical and electrometal-
lurgical processes. Solvent extraction, ion exchange, leach-
ing, inorganic chemistry, theoretical high temperature
metallurgy. (Byerley, Enns, Rempel, Spink, Wynnyckyj,
Fahidy, Scott)

POLYMER SCIENCE AND ENGINEERING GROUP
Diffusion through modified membranes, radiation graft
polymerization, emulsion polymerization, stress relaxation
in elastomers, adhesion, polymer compatibility, kinetics
and thermodynamics of polymerization reactions. (Burns,
Huang, O'Driscoll, van der Hoff, Macdonald)

MATHEMATICAL ANALYSIS AND CONTROL GROUP
Simulation, process control, applied statistics, computer
control, process analysis and dynamics, operations re-
search, optimal design and control of chemical plants.
(Chang, Fahidy, Gall, Mueller, Reilly, Rhodes, Heatley)

TRANSPORT PHENOMENA AND KINETICS GROUP
Heat and mass transfer in multiphase systems. Con-
current flow transport processes, boundary layer theory,
turbulence at mobile interfaces, frequency response


methods, diffusion. Reaction rates in inorganic and organic
systems, selectivity studies in catalysis, diluent gas effects.
(Batke, Bodnar, Dullien, Ford, Hudgins, Macdonald, Pei,
Rhodes, Scott, Silveston, Turner, Moo-Young, Robinson)
In addition to the above five groups, there is a
nascent Environmental Engineering group which
presently draws on the relevant expertise of the
other groups. As with the undergraduate pro-
grams, the department is organized to move rapid-
ly with the restructuring of its research groups
as dictated by student need and faculty expertise.
It should be also noted that interdisciplinary pro-
grams are available with such departments as
Chemistry, Biology and Management Science.
Research laboratories covering over 50,000 sq.
ft. of space are housed in a modern, air-condition-
ed building. The wide range and diversity of
equipment have never failed to impress visiting
ChE faculty. One recently tried to see it all in
one day with the result that he found himself
"completely dehydrated" at the end of a gruelling
tour.
A departmental Reading Room, a glass-blow-
ing shop, machine-shops and an electronics-shop


The programs teach students that
responsible engineers are involved not
only with the traditional role of providing
material needs but also with the quality of life


further extend the research facilities. The Uni-
versity Computer Centre also contributes greatly
to the departmental research facilities.

FACULTY PROFILES

THE OVERALL QUALITY of a department
is determined to a large extent by its faculty
members. Ours have a diversity of cultural and
education backgrounds that we treasure. Faculty
Ph.D's are from 19 different universities repre-
senting 5 different countries. As quoted in the
report of the "Advisory Committee on Academic
Planning," Council of Ontario Universities, Sept.
1974, "This is certainly an extremely important
factor in enriching the collective way of thought
and methods of training students in the depart-
ment There is a large group of very produc-
tive people (in research) and there is an excellent
spirit of cooperation among the staff, providing a
stimulating milieu for students." To give an idea
(Continued on page 39.)


WINTER 1975









views and opinions


ChE LAB: A NEW LOOK


J. M. DOUGLAS
University of Massachusetts
Amherst, Massachusetts 01002

T HERE HAS BEEN A considerable amount of
discussion of chemical engineering laboratory
courses taking place at national AIChE meetings
for the last several years. The multiple, educa-
tional purposes of these courses have been de-
scribed in some detail, and included in these goals
are: to familiarize the student with chemical
processing equipment, to help the student gain
proficiency with instruments and measurement
methodology, to teach students how to deal with
experimental errors, to allow students to practice
technical report writing, etc. Another major goal,
not included in the abbreviated list above, is to
show that the experimental data agree with the
theory that the student has learned in his courses.
In actual fact, however, very few of the experi-
ments do agree with the theory, and so the student
is required to find reasons for the discrepancies
and to discuss his reasoning in his laboratory re-
port. At this point, students normally engage in
an exercise, which I call "creative B. S." They
demonstrate an imaginative capacity far exceed-
ing even the wildest science fiction authors, in
order to find some justification of why the equip-
ment did not work properly. Although I think it
is always worthwhile to find ways to excite the
imaginations of students, I am somewhat worried
that we are doing this in the wrong context.
In addition, it seems to me that it is a
dangerous pedogogical practice to have students
carry out an experiment to verify a theory. If they
are not successful in their attempt, they can easily
draw the conclusion that the experiment (reality)
is no good, while the theory (an abstraction) is
correct. Thus the theory becomes a better de-
scription of reality than the experiment, which
becomes unreal. Obviously, faculty would not
agree with this conclusion, nor am I certain that
students accept it either; but perhaps much of
the dislike students often have for laboratory
courses is caused by this hidden conflict.


Editor's Note: The following pages deal with
the chemical engineering laboratory. We begin
this special laboratory issue with a provocative
article that suggests a new approach to
our laboratory courses.

A better approach to laboratory experimentation
might be to ask students to develop a theory to describe
the behavior of a particular piece of laboratory appara-
tus. With this approach they would need to know not
only the results of the simple theory discussed in their
courses, but also to have a good understanding of the
assumptions behind that theory. Then, when the simple
theory fails to predict the observed behavior, the students
would have to determine which one, or more, of the
assumptions were not valid and to modify these assump-
tions in an attempt to develop a more realistic model. In
this way, they would evolve a workable theory.
Although this approach is more time con-
suming than a traditional experiment and is much
more difficult (it requires a great deal more
thought on the part of the student) it should
give them an improved understanding of the re-
lationship between theory and practice. In
particular, some clever students may recognize
that there are alternate approaches to the prob-
lem; some groups may attempt to redesign the
equipment so that the assumptions for the simple
theory are satisfied, others may develop a set of
correlations to provide correction factors for the
simple theory so that it agrees with the observed
data, and others may develop more sophisticated
theoretical models. Thus, the class would learn
that there are no unique solutions to engineering
problems, they would gain additional insight into
the differences between interpolation and extra-
polation, and they would have a better apprecia-
tion for the real world they will encounter when
they leave the university.
As an alternate approach to resolving the discrepancy
between experimental observations and simple theories,
the student could be asked to develop a trouble-shooting
procedure for a particular piece of equipment. That is,
he would be assigned a task of devising a way of im-
proving the performance of the system (assuming that
the simple theory predicts a better performance than
that exhibited by the equipment) or to determine why


CHEMICAL ENGINEERING EDUCATION


I ChE "I









the existing equipment fails to meet the designed specifi-
cations (where the design is based on simple theory).
Problems of this type will be more time consuming than
conventional experiments but they have the advantage of
exposing students to some engineering concepts that are
not normally treated in the curriculum, such as the time
and cost required to make additional measurements or to
modify existing equipment, the use of intuition rather than
theory to design flow distributors and other apparatus,
the difficulty of communicating your ideas clearly to
technicians, etc.

SOLVING ENGINEERING PROBLEMS
ANOTHER GOAL THAT APPEARS to be
lacking in laboratory courses is the idea of
solving engineering problems experimentally.
Most of the effort in chemical engineering curricu-
la is directed toward analysis, and we describe
successively more sophisticated theories for solv-
ing selected engineering problems. Laboratory
courses are used to demonstrate the validity of
these theories, more or less, and the design
course is used to introduce the ideas of synthesis,
as well as to integrate the previous courses in
analysis. Depending on the individual who teaches
the design course, I'm certain that there is some
discussion of how to select the "right" tool to
solve a particular problem, although none of the
design texts that I am familiar with treat this
topic. Moreover, I doubt if there are many design
courses that are so closely integrated with a
laboratory course that students ever gain much
feeling for how to decide whether to take an ex-
perimental or theoretical approach to solve a
particular problem.
One method we might use to help students
understand the limitation of simple theories, the
relationship between theory and practice, and the
relative effort associated with both experimenta-
tion and analysis, is to orient at least some of the
laboratory course more toward the solution of
engineering problems. For example, we could ask
students to develop correlations for head losses in
pipe fittings, pump efficiencies, film heat-transfer
coefficients, etc. for a non-Newtonian fluid. It
should be easy to find examples where Newtonian
data are available in the literature, but the cor-
responding results for a power-law fluid, for
example, are lacking. Moreover, it should be re-
latively simple to convince students of the poten-
tial applicability of the results, so that perhaps
they will become better motivated towards ex-
perimentation. Of course, before taking data with
a non-Newtonian fluid, it would seem reasonable


to attempt to reproduce the reported results for
Newtonian fluids (which would mean that we
would carry out many of the normal fluid
mechanics and/or heat transfer experiments in
a context where they were a means to an end,
rather than an end in themselves). In addition, a
focus on non-Newtonian fluids might make it
possible to develop a better integration between
lecture and laboratory courses by deriving the ap-
propriate solutions for simple flow configurations
and demonstrating the extension of dimensional
analysis for complex systems in the lecture for
the systems that will be studied in the laboratory.
Still another concept that is probably best presented
in a laboratory context is that most engineering problems
must be approached in an iterative fashion, that it is
necessary to know the answer to a problem, at least ap-
proximately in order to formulate the problem. Thus if
we recognize that we will be forced to solve real engineer-
ing problems more than once, (in contrast to text book
problems), we want to start with very simple, even though
crude, predictive methods, and then proceed to more
sophisticated algorithms as long as there is an economic
incentive. As a simple although possibly painful, illustra-
tion of the importance of this "engineering method," we
could ask students to develop a statistical experimental
design for a batch reaction system where they have
difficulty in finding any published information on the
approximate half-life or reaction rate period. Indeed, an
assignment of this type might provide an interesting
"academic" experiment of how much engineering intuition
students gain from an engineering education.




..It is a dangerous pedogogical practice
to have students carry out an experiment to
verify a theory. If they are unsuccessful, they
can easily conclude that the experiment (reality)
is no good, while the theory (an
abstraction) is correct.




CONCLUSION

In conclusion, perhaps I should admit that it is always
easy for a poor experimentalist like myself to criticize the
efforts of others. Also, I recognize that the program I am
proposing calls for more sophistication on the part of
the student than our traditional laboratory courses. How-
ever, perhaps a portion of the class would respond more
favorably to an open-ended laboratory such as I suggest,
and the remainder of the students could do the convention-
al experiments. Another advantage of the laboratory is
that it may produce some data which prove to be useful
to the profession, and thereby encourage more contact
between the university and industry. []


WINTER 1975









[0 0 laboratory


FLOW CURVE DETERMINATION

FOR NON-NEWTONIAN FLUIDS


WALTER P. WALAWENDER
and T. Y. CHEN
Kansas State University
Manhattan, Kansas 66506

T HIS REPORT DESCRIBES a student labora-
tory experiment for the determination of the
flow curve of a non-Newtonian fluid using a
capillary viscometer with continuously varying
pressure head. The experiment exposes the
student to the concepts of non-Newtonian flow
analysis, as well as non-linear parameter estima-
tion techniques. Computer aided data analysis is
included as part of the experiment.

APPARATUS AND PROCEDURE
The viscometer is shown schematically in Fig.
1. It is a modification of one described some years


ago by Cerny [1]. The instrument consists pri-
marily of a precision bore capillary A and a 50
c.c. buret B. The capillary A is placed horizontally
with one end inserted into a rubber stopper which
is sealed to the collecting flask F and the other end
connected to the buret B by means of a piece of
tygon tubing. The pinch clamp C is a convenience
for filling the viscometer. The flask F has a side-
arm which is extended with a piece of tubing
to the atmosphere. The buret B is jacketed by a
2-inch diameter glass tube. The water bath is
kept at a desired temperature by a regulator G.
The regulator unit contains a pump which is used
for circulation of water through the jacket. This
arrangement assures constant temperature for
the measurements.
In operation, the buret, connecting tubing and
capillary are filled with the test fluid and the
clamp C put in place. Care should be taken to
avoid trapping bubbles in the line. Generally the
buret is filled well above the top graduation. If
the test fluid is not at the bath temperature, about
10 minutes should be allowed to bring it up to
bath temperature before starting a run. A run is
started by opening clamp C, permitting the fluid
in the buret to flow through the capillary. A stop-
watch with a split hand feature is used to time
the descent of the meniscus in the buret at selected
graduations (i.e. 0, 5, 10, 15, .). The times
corresponding to the selected graduations are re-
corded. Readings can be taken until the meniscus
passes the last graduation on the buret or until
the descent of the meniscus is too slow to be
measurable. A minimum of three sets of gradua-
tion (x) versus time data are taken for a given
sample. An average of the three sets is used for
data analysis.

SUPPORTING DATA

T HE LENGTH OF THE capillary is measured
directly. The capillary radius is determined
by filling it with mercury, weighing the thread of
mercury, and calculating the radius from the


CHEMICAL ENGINEERING EDUCATION


Fig. I Schematic diagram of the apparatus.



















"''


A lm .....,

Walter P. Walawender is an Assistant Professor of Chemical
Engineering at Kansas State University. He received his under-
graduate training in Chemistry at Utica College and his M.S. and
Ph.D. degrees in Chemical Engineering from Syracuse University.
His current research interests include modeling of blood flow in
the microcirculation and gasification of agricultural wastes. He
teaches a variety of courses at both the graduate and undergradu-
ate level.
Te Yu Chen received his bachelor's degree from National Taiwan
University and his master's degree from Kansas State University,
both in Chemical Engineering. He is a graduate research assistant at
KSU. His current research areas are fluidization and the gasification
of agricultural wastes.


volume of the thread. The volume is given by V =
(mass of Hg) (density of Hg at measurement
temperature). The radius then follows from R =
(V/ 7rL)1/2. A minimum of three determinations
are recommended.
The buret cross section is determined by
measuring the distance between terminal gradua-
tions (i.e. ho hso) and dividing the buret volume
by this result.

A = 50/ (h0 h50)
A relation between the buret graduations and
the height of the meniscus relative to the capillary
outlet is also required for data analysis. Noting
the buret graduation as x and the measured
distance between the last buret graduation and
the capillary outlet as (hso he), the following
expression can be written
h=50-x xh
h = 50 A- x + (h50 h
(1)
This gives the height of the meniscus relative to
the capillary as a function of the buret graduation
reading x.
The test fluid density, if unknown, is deter-
mined at the bath temperature with the aid of a
pycnometer.


THEORETICAL

T HE FLOW SITUATION of the present vis-
cometer is very similar to that of a problem
presented by Bird et al. [2]. Hence a quasi steady-
state approach is used for the theoretical analysis.
The theoretical development for Newtonian flow
in this viscometer has been discussed by Cerny
[1] and is outlined below. This will be followed by
the analysis for non-Newtonian flow. The flow of
a Newtonian fluid in a capillary tube is described
by the Poiseuille, equation,
AP = 8n LQ
tRuf
(2)
This expression relates the pressure drop AP
across the capillary (of radius R and length L) to
the volume rate of flow Q and the coefficient of
viscosity 7T. For the viscometer the pressure drop
at any moment is also given by
AP = pgh
(3)
where h is the height of liquid column in the
buret relative to the capillary, p the fluid density
and g the acceleration of gravity. The volume rate
of flow at any moment can be expressed as
dh
Q -A dt
(4)
where A is the cross sectional, area of the buret.



The experiment exposes the student to the
concepts of non-Newtonian flow analysis as well
as non-linear parameter estimation techniques.
Computer aided data analysis is included
as part of the experiment.



The combination of equations (2), (3) and (4),
followed by integration results in an expression
relating h and t
(5)

n h t + C = t +C = mt+ C
8LAn n

where


B =-
8LA


and m= -Bp
and m =


Thus a plot of logoh versus t should be linear.
The viscosity of a Newtonian fluid can be evaluat-
ed from the slope (m) provided that the instru-


WINTER 1975








mental dimensions and the fluid density are
known.
In the case of a non-Newtonian fluid, the "vis-
cosity" is not constant and varies with the rate of
flow or more properly the rate of shear. The log
h versus t plot gives a curve with m varying from
point to point. This variation can be utilized to
relate the wall shear rate yw to the wall shear
stress Tw from which a flow curve T, versus yw
can be constructed. An approach similar to that
developed by Krieger and Maron [3] is employed.


The experiment described in this
report provides for student exposure
to non-Newtonian flow as well as
computer aided data analysis.
Several types of fluids can be employed
to illustrate types of flow behavior.


First, an effective fluidity is defined, v
reference to equation (2) as
= 1 -8LQ
e e TR4AP


where -e is the effective viscosity. From the
pressions in equation (5) it can be seen tha
is given by
m-
e Bp

Under conditions of steady, laminar flow
a time-independent fluid through a cylinder
tube, it can be readily shown [4, 5] that


Q3 = :
'irR TW


2
rw T f (t) dr


where
RAP ; f(T) = y
w 2L
(9,
Combination of equations (6), (8), and
gives

= 4 W T2 f(T) dT
e R T r
W W

(
Differentiation of equation (11) with respect


vith


tv using Leibnitz's rule and rearrangement of the
result gives
T d In e
w w
(12)
The terms in 0, and r7, in equation (12) are re-
placed by equations (7) and (9) so that after
some algebais manipulation equation (12) be-
comes
-W m ( 1 dm
T Bp (1 + dt
w 4m
(13)
Equation (13), coupled with equation (9), is
used to determine the flow curve of a non-New-
tonian fluid.

DATA ANALYSIS
T HE AVERAGE OF the x versus time data is
first converted into h versus t with the aid
of equation (1). Equations (3) and (9) give the
wall shear stress
w 2pgh
w 2L


(6) (14)
ex- which can be readily evaluated. To evaluate the
t e wall shear rate from equation (13) values for m
and dm/dt are required. This information can
be obtained from the h versus t data with the aid
of a non-linear parameter estimation technique
(Bard's method [6]). Bard's method is in the form
of a computer program provided by IBM. The user
of must supply the mathematical model, initial
ical guesses and the bounds on the parameters, and
the experimental data. The outputs include the
estimated parameter values and the deviation of
computed values from observed data values. From
the deviation one can judge how well the proposed
(8) model fits the data points.
From the data examined, it appears that the
h versus t data can be described by a function of
the form


10)
(9)





11)
t to


h = h exp {-kt + (a + b t)c}
(15)
where
ho = h value when t equals to zero
(measured)
k, a, b, c = parameters to be estimated
The parameters a, b and c in equation (15) result
from the non-linearity of a In h versus plot. For
the initial guesses of the parameters, k can be


CHEMICAL ENGINEERING EDUCATION










taken as the negative value of the slope of a line
fitting the first few points of the In h versus t
plot. An initial guess for the parameter c is taken
as 2. The parameters a and b can then be
estimated as the intercept and the slope of the
least-square-fit line of a V8 versus t plot, respec-
tively, with 8 defined by*
6 = In h In h + kt
O
(16)
Only a rough estimation for these parameters is
sufficient and this can be easily done on a pro-
grammable desk calculator, or available computer
program such as the IBM scientific subroutines
package.
Both upper and lower bounds must be supplied
in the input. The determination of these bounds
is somewhat arbitrary. The bounds as suggested
from this study are the following,

1) k: initial guess x (1.00 0.30)

2) a: 0 < jai < 0.1 (17a)

3) b: 0 < b < 0.01 (17b)
(17c)
4) c: 1 < c < 5 (17d)
where the upper bounds of |ai and b are arbi-
trarily chosen as one order of magnitude greater
than the values ordinarily encountered.
The parameters estimated by the computer
program can be used to analytically evaluate mn
and dm/dt. From equation (15),

m d I- h -k + cb(a +bt)c-
m dt
(18)
From equation (18), dm/dt results,
dm 2 c-2
d- = c(c-1) b (a + bt)
(19)
For the special case of slight curvature of the In
h versus t data one can generally obtain a satis-
factory description of the data by setting c = 2.
This reduces the computer time required and
eliminates one parameter from the parameter esti-
mation. Substitution of equations (18) and (19)
into equation (13) gives an expression for
yw/rw in terms of the parameters. The evaluation
of m, dm/dt, rw, and yw /rw can be done on the
computer with a slight addition to the original
Bard's program. In this way, the flow curve in-


*It is apparent that 8 represents the deviation of a In
h versus t plot from linearity. This deviation usually is
a quadratic function of t. Accordingly, equation (15) was
formulated.


fable 1. Results for thl trust fluid


Tim., L ". I,
(sec) (cm)


In exp'1


heI'd (dn
(-m) (dyne/cm2) (-ee-1)


4.0342 56.54
4.0153 55.45
3.9762 53.31
1.9155 51.15
1.8932 'I 49.06
46.91
44.9mi
42.70
40.55
3J.h4 2 .0'2 .14 38.42
34.19
32.08
31.01
1. 59, .00)7 .,)8 21 .91
2'.87
27.82
26,795
25.66
3.2(144 .017 .1 2' .6
23.56
22.51
20.41
:.961 .l .13 19.35
18.30
17.25
16.20
15.07
2.6405 .h41 .3 14.05
12.97
11.90
10.84
9.76
2.1645 .143 .38 8.67
7.58


formation, r and y, is obtained directly as com-
puter output. A print-out of the program can be
obtained by writing the authors.


AN EXAMPLE OF THE METHOD

PRESSURE FLOW DATA (in the form of h
versus t) for a non-Newtonian fluid are used
to illustrate the procedure. The fitted h versus t
curve is then compared with experimental values.
The best fit parameters are then employed for the
determination of the flow curve for the fluid. For
this example, it was assumed that c = 2.
Reference is made to Table 1. Column 2 gives
the h values converted from raw data of x versus
t by equation (1). Column 3 presents In h values
which are used for the initial guess of k. A least
square fit of these data in the form of In hexpi
versus t is made with a programmable Wang cal-
culator. The result for this case gives a slope of
-0.0024819. Hence the initial guess of k is taken
as 0.0024819. Values of 6 are then calculated as


1 .a1. 2. Vales For varies ODaramleters


initial guesss
lower bound
upper bound
estimated parameter


0. 0024819 -0.031137 0.00049889
0.001737 -0.1 0.
0.0032263 0 0.01
0.0024855 -0.025336 0.00054924


WINTER 1975









indicated by equation (16). The values of 8 and
V8 are tabulated in columns 4 and 5. The V8
data are used for the initial guesses of parameters
a and b. The (V8 versus t) data are fitted by least
squares with the aid of a programmable calcula-
tor. The resulting intercept and slope give the
initial guesses of a and b, respectively. These
values are presented in Table 2. Bounds for para-
meters calculated by the program are also shown
in Table 2. These parameter values are used in
the program to calculate h values by equation
(15). The resulting h values are presented in
column 6 of Table 1. A comparison between the
best fit curve and the experimental data is given
in Fig. 2. As can be seen from the figure the fitted


55










35-








o. 0 rFitted curve
o Doto Points






100 200 300 400 500 600 700 800 900
Time, sec
Fig.2. A typical fitted curve for h vs.t data.

curve describes the experimental points very well.
The error in hcnad, as can be seen in Table 1, never
exceeds 1%.
Next T,- and w,., as given by,
S Rpgh -i + 1 din
T = ; and Y = T {i +
w 2L w w Bp 4m2 dt
(15, 13)
are evaluated, using the estimated parameters.
Here h, m and dm/dt are given in terms of the
parameters by equations (15), (18) and (19).


The results are shown in column 7 and 8 of Table
1 as well as in figure 3. As shown in Fig. 3. the
shear rate range from a single determination
covers about one cycle. The flow curve of non-unit
slope indicates the non-Newtonian behavior of the
test-fluid.


2000


50O
Tw sec'I

Fig.3. The flow curve.


STUDENT RESULTS

SEVERAL STUDENTS conducted the experiment with
a 0.05% (wt) solution of CMC in water. The
capillary employed was 19.88 cm long and had an inside
diameter of 0.1020 cm. Reproducibility of the raw data
(x vs t) was quite good with agreement within '/2% on
the total flow time of approximately 750 seconds. For this
fluid, the parameter c could not be taken as 2 and was
estimated along with the other parameters. A typical h
versus t curve is shown in Fig. 4. As can be seen the
agreement is quite good. A typical flow curve is shown
in Fig. 5. For the CMC sample employed, one can observe
the trend towards the "zero shear" limiting viscosity by
replotting the data in the form of 7 versus y
(77 = T/y).










.0

filled curve "
0 dot. 0oi.
o---


F 4 H vst cmrve


CHEMICAL ENGINEERING EDUCATION










SUMMARY
N SUMMARY THE experiment described in
this report provides for student exposure to
non-Newtonian flow as well as computer aided
data analysis. Several types of fluids can be em-
ployed to illustrate the various types of flow be-
havior. In utilizing this experiment it is suggested
that several diameters of capillary be available in
order to ensure reasonable experiment length
(total flow time) as well as to provide for greater
variation in shear rate. ]l


10-


ow curve for c'
Fig 5. Flow curve for CMC solution.


ACKNOWLEDGMENT
This work was supported in part by a


Kansas Heart Association #KR-72-10. This support is
gratefully acknowledged. The efforts of the junior
Chemical Engineering students (1973-74) in testing the
experiment are greatly appreciated.

LITERATURE CITED
1. Cerny, L. C., Am. J. Phys., 29, 708, 1961.
2. Bird, R. B., Stewart, W. E., and Lightfoot, E. N.,
Transport Phenomena, p. 237, problem 7.M, John
Wiley & Sons, Inc., New York, 1960.
3. Maron, S. H., Krieger, I. M., and Sisko, A. W., J. Appl.
Phys., 25, 971, No. 8, 1954.
4. Skelland, A. H. P., Non-Newtonian Flow and Heat
Transfer, John Wiley & Sons, Inc., New York, 1967.
5. Wilkinson, W. L., Non-Newtonian Fluids, Pergamon
Press, London, 1960.
6. Bard, Y., "Non-linear Parameter Estimation and Pro-
gramming," IBM New York Scientific Center, De-
cember 1967.


APPENDIX
A printout of the computer program is avail-
able. It consists of seven decks; a main program
and six subroutines. Definitions of the variables
o' ',ooo added are given in the comment statements.
Names of the other subroutines are given to show
the entire structure of the program. For details of
the entire technique, reference can be made to
grant from Bard's original manual [6].


ARE YOU APPLICATIONS ORIENTED?


At Fluor Engineers and Constructors, Inc. our 4
billion dollar plus backlog offers all kinds of practical
applications opportunities for chemical engineers to
help provide solutions to the energy problem.
At Fluor Engineers and Constructors, Inc. we de-
sign and build facilities for the hydrocarbon processing
industry-oil refineries, gas processing plants, and
petrochemical installations. We are very active in
liquefied natural gas, methyl fuel, coal conversion, and
nuclear fuel processing.


If you want to find out about opportunities, loca-
tions you can work in (world wide) and why Fluor is
the best place to apply what you have learned, meet
with the Fluor recruiter when he comes to your campus
or contact the College Relations Department directly.

Fluor Engineers and Constructors, Inc.
1001 East Ball Road
Anaheim, CA 92805


W FLEU OR ENGINEERS AND
Nf FLUORiXCONSTRUCTORS, INC.


WINTER 1975


J











TEACHING PROCESS SYNTHESIS --

The Integration of Plant Design and Senior Laboratory


K. A. OVERHOLSER, C. C. WOLTZ, and
T. M. GODBOLD
Vanderbilt University
Nashville, Tennessee 37235

T HE CURRENT ATTEMPT at Vanderbilt
University is to organize our undergraduate
chemical engineering curriculum around process
synthesis and design, rather than around trans-
port phenomena or the traditional unit operations
sequence. The students acquire a firm foundation
in the engineering sciences of mechanics, thermo-
dynamics, and the transport and electrical phe-
nomena, but the emphasis in the ChE core
courses is on design, beginning with flow sheet
generation in the sophomore "stoichiometry"
course and culminating in the senior plant design
project. Such an approach requires a careful
effort to develop problems and case studies, but
we feel that the effort is justified by a closer ap-
proximation to modern ChE practice.
Until recently, the laboratory courses have
not contributed directly to this curriculum. They
have tended to emphasize the understanding of
physical principles, report writing, team work,
and the development of planning and reasoning
abilities, but they have done so through a series
of self-contained experiments which were all too
often unrealistically well defined.
Nevertheless, a second-semester senior de-
velops a curious enthusiasm for his ChE labora-
tory work. He sniffs the air, realizes what may be
expected of him in a few months, and begins to
approach his laboratory work in mature and pro-
ductive fashion.


We saw an opportunity to combine the phe-
nomenon of senior lab motivation with our design
emphasis. It seemed particularly appropriate to
seek the close involvement of industry. This paper
describes our first serious attempt to combine
laboratory work, industrial contact, and "plant de-
sign" into one five-semester hour course. We as-
signed, with the help of chemical engineers and
chemists in local practice, a semester-long process
design for which data might be unavailable. The
students had to decide what information to obtain
in the laboratory, perform the appropriate experi-
ments, complete their process design, and report
to their industrial and faculty advisors. Because
many other schools are moving toward a design-
oriented curriculum, we felt that our experience
might supply some insight into the advantages
and disadvantages of an integrated laboratory-
design approach.

COURSE OBJECTIVES
W HEN TIE COMBINED course was in the
planning stages, we identified five objec-
tives:
First, we hoped that the students could gain
some confidence in their ability as engineers. In
order for this objective to be realized, we would
have to pick a difficult project with a good chance
of successful completion. If the class could com-
plete such an assignment, they would justifiably
feel a sense of accomplishment and pride. It was
important that the assignment not be totally
artificial, but be as realistic as possible.
Second, we wanted the students to see the real


The integration of plant design and lab was sol successful that we see no reason to return to our old
system We enthusiastically recommend the joint lab design approach. If you try it, you might
consider four points which we feel to be of paramount importance. The cooperation of an accessible
industry is essential; a suitable problem must ibe chosen; a great deal of advance planning is
necessary; consider your equipment constraints' in advance planning is necessary. Consider your
equipment constraints in advance.


CHEMICAL ENGINEERING EDUCATION









utility of engineering experimentation. Instead of
requiring the students to spend one afternoon a
week verifying physical laws or measuring proper-
ties, they would be expected to resort to labora-
tory work only when the data required for the
plant design could not be obtained from alternate
sources. They would have to decide what informa-
tion was needed. They would have to design the
experiments.
Our third goal involved the development of the
managerial skills required to efficiently carry out
a long, complex project. It is important for young


.4 .


engineers to learn how to organize and communi-
cate among themselves.
Next, we hoped that the lab would help give
a physical feel for the plant design project. Most
of us, when assigned an engineering job, have at
least seen the materials and processes with which
we are asked to work. This is rarely the case in
a senior design project.
Finally, we hope to develop contact between
the students and practicing chemists and chemical
engineers, contact based on technical matters of
joint interest. Seniors want this contact; too often
they get it only in job recruitment situations.

THE PROBLEM
T HE PROBLEM WAS PRESENTED to the
students at the first plant design session and
during the first lab period in the following form:
"Design a plant to produce 100 million pounds of
polyester melt from the raw materials DMT and
ethylene glycol. The plant is to be located on a
1000 acre spread on the Cumberland River near
Nashville, Tennessee."
The process to be used was basically that of the
DuPont Old Hickory Plant. This facility produces
Dacron (polyethylene terephthalate) from nitric


K. A. Overholser, the laboratory instructor in this project, re-
ceived his Ph.D. in chemical engineering from the University of
Wisconsin and was a N.A.T.O. postdoctoral research fellow at Im-
perial College, London. His research activities include hemorheology
and combustion physics. (Left)
C. C. Woltz was the student project leader. He is now a gradu-
ate student in chemical engineering at Vanderbilt. (Left above)
T. M. Godbold, instructor for the Plant Design course, received
his B.S. and M.S. from the University of South Carolina and his
Ph.D. from North Carolina State University. He has industrial ex-
perience with DuPont and Celanese and has been a consultant for
several companies. His areas of interest include process control and
diffusional operations. (Right above)


acid, xylene, methanol, and ethylene glycol. Para-
xylene and nitric acid react to form terephthalic
acid which is then combined with methanol to
form dimethyl terephthalate (DMT). The DMT is
fed to transesterification reactors where it is com-
bined with ethylene glycol to form methanol and
ester monomer (bis-hydroxyethyl terephthalate,
or BHET). The monomer is polymerized under
vacuum, yielding ethylene glycol for recycle; the
resulting highly viscous polyester melt is spun
and packaged.
Some initial ground rules were stated:

The entire ChE faculty will answer all questions to
which they know the answers and will supply any fac-
tual information to which they have ready access. The
students were encouraged to make use of all of the
faculty as consultants.
The DuPont staff will help and answer questions within
proprietary limitations.
Any of the ChE lab and computer facilities may be
used at any time, subject to our safety rules.
The library and the patent files should be used as ex-
tensively as time allows. Don't take data in the lab if
you can find it (and trust it) elsewhere.
Data and information discovered by anyone will be
made available to the class as a whole.


WINTER 1975


Tfail' '4"'








* Each student must design his own plant, although stu-
dents may work together until all laboratory data re-
quired are obtained.

The class was given a supply of raw DMT by
DuPont. The firm also supplied a small quantify
of recrystallized BHET for quality comparisons
and determination of physical properties.
The ChE Program supplied antifreeze from
which the class could obtain ethylene glycol if
they so chose.



a second-semester senior develops a
curious enthusiasm for laboratory work.
He sniffs the air, realizes what may
be expected of him in a few months,
and begins to approach his lab work
in mature and productive fashion.


From this point until the end of the semester
the class was on its own in the design and lab
project, receiving only occasional unrequested
advice from the faculty.

CLASS MEETINGS
T HE PLANT DESIGN PORTION was offered
for three semester credit hours. In the frst
third of the course (while the lab was getting
started), the students reviewed and practiced
equipment sizing and design decisions on several
case studies. Although the class had had a course
in Engineering Economy, methods of economic
analysis and optimization were briefly reviewed
and expanded to meet the anticipated needs of the
Plant Design. The primary texts for this course
were Perry's Handbook [1] and Peters and Tim-
merhaus [2]. During the latter half of the
semester, the class did not meet formally, but stu-
dents were strongly encouraged to meet with the
design professor once a week to discuss design
problems and report their progress. This weekly
meeting provided an opportunity to discuss design
and lab progress as well as exchange information.
The Laboratory portion met once a week from
8 a.m. to noon. All lab work was devoted to the
design project. Each session began with coffee,
donuts, and a report meeting, after which, the
students would begin experiments, library re-
search, or planning. It was often necessary to
work additional hours outside of this period. The


students had obtained much of the physical
property data that they needed about six weeks
before the end of the semester. The overall
process flow sheet was fixed by discussion at this
time and the students began sizing equipment for
their design. Laboratory data on the kinetics for
the process was completed about three weeks be-
fore the end of the semester. At that time, the lab
stopped meeting formally.


CHAOS AND ORDER
T HE FIRST TWO LAB meetings were, predict-
ably, mixtures of order and chaos. The prob-
lem was laid before the class, a temporary discus-
sion chairman was appointed, and the group was
left on their own to lay plans.
After an hour or so, the group decided to go
to the laboratory and get started (they planned
to measure the melting point of DMT). At this
point the laboratory instructor established an ap-
parently arbitrary rule:
* Even though this is a lab course, no one may go to the
lab for the first two weeks.
(Note that intervention was essential at this
point-left entirely to their own devices in the
initial planning stages, the class might well have
embarked on a course which would surely have
led to failure in the end.) The students were thus
forced back on the track, and they finally got
around to posing such questions as "what do we
need to know in order to design this plant?" and
"How can we find the information we require?"
The discussion proceeded relatively smoothly
through the next four hours. The instructors did
not participate, except to supply factual informa-
tion as requested, but did assign a new discussion
leader every forty minutes. By the end of the day,
after much backing and filling, it had been decided
that the following information would be sought:
* Kinetic and thermodynamic equilibrium data for the
reaction of DMT and ethylene glycol over a range of
different temperatures, initial concentrations, and
catalyst concentrations.
* Kinetic data for the polymerization step.
* Information on the nature of polymerizers and stirring
mechanisms.
* Information on possible catalysts for the DMT/glycol
reaction so that a suitable catalyst might be selected.
* Physical properties (viscosity, melting and boiling
points, thermal conductivity, specific gravity) and
thermodynamic data (heats of fusion, vaporization,
solution, and reaction) for all components and mix-
tures involved.


CHEMICAL ENGINEERING EDUCATION








* Heat transfer coefficients for the process streams.
* Methods for analyzing the samples from reactor ex-
periments.
* Phase equilibrium data for the glycol-methanol-DMT
system.
* Costs of raw materials, utilities, transportation, etc.
* Information on appropriate safety precautions against
burns, fires, and dust explosions (these and other haz-
ards were identified at the outset by the instructors
and by the industrial advisors).
The class split into three groups, each group
taking responsibility for obtaining some of the
data in the above list. The Kinetics group was
responsible for identifying and gathering all in-
formation necessary for the specification and de-
sign of the transesterification reactor. The Sepa-
rations group took responsibility for all labora-
tory separations (e.g., separating ethylene glycol
from antifreeze) and for obtaining information
relevant to the process separations. The third
group was responsible for obtaining all physical
properties which might be needed to estimate heat-
transfer coefficients and friction factors. They
were also charged with devising laboratory
analytical procedures and with analyzing samples
generated by the other two groups. This third
group was called FHA (flow, heat transfer, and
analysis) group.
The lab instructor picked a team leader for
each group based on past performance and on
performance during the initial discussion 'period.
One student was charged with the responsibility
of coordinating the three groups, acting as liaison
between students and faculty, and setting up a
timetable to insure that all data would be obtained
before the end of the semester.
The organizational structure is shown in
Figure 1.

REPORTING SYSTEM
EFFECTIVE COMMUNICATION was par-
ticularly important in this project. It was es-



It was necessary for the instructors
to guide the group away from a
proposed semi-infinite series of
univariant experiments. To avoid excessive
experimentation, the group chose to plan
their work using an incomplete
factorial method.


COURSE ORGANIZATION
Figure I

sential, for example, that the necessary experi-
mental equipment and supplies for a week's work
be set up beforehand. The project and group lead-
ers had to anticipate their needs and communi-
cate them to the lab instructor and shop tech-
nician. Since each student had to design his own
plant in the end, it was essential that he under-
stand where the data were coming from and
learn how the other groups were solving their
problems.
To accommodate these communications needs,
a reporting system was set up. Once a week, each
group member would submit a short written re-
port of last week's results and this week's plans to
his group leader, who would read them, add a
cover report of his own, and pass them on to the
student project leader. The project leader met
with the lab professor each Friday afternoon to
discuss reports and problems and to compare
progress to the timetable. Group leaders and
group members were often asked to attend these
Friday meetings.
In addition to the written reports, short oral
reports were given by representatives of each
group at the beginning of each lab period.

LABORATORY WORK
Kinetics Group
Based on a preliminary library investigation
and on a limited acquaintance with the DuPont
process, the Kinetics group identified three


WINTER 1975








variables upon which production rate might de-
pend and set ranges over which they would take
data on the reaction of DMT and glycol to form
BHET. These ranges were:
Reactor temperature: 180-200 C
Manganese acetate catalyst
concentration: 175-275 ppm
Reactor feed mole ratio:
4:1 to 6:1 mole glycol/mole DMT
Time was not available to investigate the effect
of pressure and different catalysts.
It was necessary for the instructors to guide
the group away from a proposed semi-infinite
series of univarient experiments. To avoid ex-
cessive experimentation, the group chose to plan
their work using an incomplete factorial method.
The reaction was carried out in two electrically-heated,
stirred, batch reactors at constant pressure. The concen-
tration of BHET as a function of time was determined by
condensing the methanol and measuring its volume as it
was evolved. The reactor system was quite complicated
and plagued with problems such as non-isothermal ope-
ration, loss of methanol and boil over of ethylene glycol.
The students also got bogged down a few times in the
kinetic analysis of their data.
The kinetics group finally obtained thirteen sets of
smooth concentration-time data. Their library search,
meanwhile, had turned up one appropriate study of the
kinetics of their reaction [3]. The reaction rate equation
proposed in the reference, however, was found inadequate
for conversion levels above 85%; it was necessary for the
students to fit their own rate expression. They proposed
a model involving a monosubstituted intermediate. The
model was found to fit the data quite well, even at high
conversions. A computer program was written to integrate
the set of differential equations. Given molar feed ratio,
catalyst concentration, reactor temperature, and physical
properties, the program predicted per cent conversion
and rate of BHET production. It was invaluable in later
repetitive attempts to seek optimal plant design.
An energy balance around the reactor re-
vealed that the heat of the transesterification step
was approximately 115 Kcal/mole DMT. This
value along with the kinetics computer programs
and some qualitative information on similar re-
actors as found in the literature, was all that the
students felt was needed to design the ester ex-
change reactor.
Since the necessary equipment was unavail-
able, the polymerization reaction could not be
studied in the laboratory. Fortunately, the stu-
dents found a paper [4] and a patent [5] with the
essential information.

Separations Group
This group had no difficulty obtaining the


ethylene glycol from antifreeze, and they rather
quickly located vapor-liquid equilibrium data for
the methanol-glycol system [6]. A series of glass-
ware experiments revealed that the presence of
DMT should have little effect on the design cal-
culations for the separation of methanol and gly-
col. Since their work was finished early, the Sepa-
rations group spent the rest of the semester help-
ing the other two groups.

FHA Group

The most important task of this group was
to obtain enough information to enable the class
to size the heat exchange equipment and pipes and
pumps. They realized from the start that the job
was most efficiently accomplished not by designing
and building special devices for measuring heat-
transfer coefficients, friction factors, etc., but in-
stead to measure or find physical properties
(particularly for mixtures) and use presently
design correlations.
The physical properties of the glycol were easy
to find, the properties of molten DMT a bit less
so. It was necessary to measure many of the pro-
perties of BHET and almost all of the properties
of glycol/DMT/BHET mixtures over the relevant
temperature and concentration ranges as specified
by the Kinetics group. Melting points, densities,
heat capacities, and viscosities were measured.
Interesting experimental problems resulted from
the relatively high (2500 C) temperature involved.
All three groups were successful in obtaining



The students saw a finished piece
of work; they performed in a mature,
professional fashion; and they demonstrated a
strong sense of accomplishment and pride
after their presentation to industry .



the data needed in the design project before the
end of the term. The data, along with useful cor-
relations found in the literature, were compiled
by the group leaders and distributed to the class.

FINAL REPORTS

EACH STUDENT SUBMITTED a formal,
written design report at the end of the
semester. Although some ideas (and all raw data)
were common to the reports, the students did not


CHEMICAL ENGINEERING EDUCATION









work together on equipment design. They were
allowed to discuss their ideas on data require-
ments and the overall process flow sheet. When it
was agreed that all the essential data were avail-
able, each student worked independently.
Both the lab and the design courses culminated in a
seminar presented jointly to representatives from DuPont
and to the Vanderbilt ChE faculty and students. Class
representatives spoke for five minutes each on aspects
of the laboratory or plant design; the talks were arranged
so that the presentation would proceed smoothly and
logically from problem statement and organization
through experimentation and design to economic evalua-
tion and optimization. The formal presentation was fol-
lowed by an informal luncheon discussion between the
student participants and their industrial advisors.

EVALUATION

T HE JOINT PROJECT WAS successful from
the standpoints of students, industry, and
faculty. The two courses complimented each other
appropriately, and all of our objectives were met,
at least to some degree. The students were able
to see the results of a finished piece of work. They
did well; they performed in a mature, professional
fashion. They demonstrated a strong sense of ac-
complishment and pride after their oral presen-
tation to industry. Our goals were accomplished
with a minimum of artificial rules, imitation
engineering or pressure and guidance from the
faculty. There were problems:
* Students from one group had a difficult time fully under-
standing what was being done in the other groups, or
occasionally even by a different member of their own
group. In order to gather data as rapidly as possible,
specialization was the order of the day. For instance,
one student would analyze samples for a month while
another group would run the reactor. While this may
be efficient it is not a desirable situation since the man
analyzing the samples would not have a good feel for
the kinetics.
Although our industrial consultants were always ready
to help, the students failed to take full advantage of
the situation; student industry interaction could have
been better.
The weekly reports were often poor; insufficient feed-
back was provided.

FUTURE PLANS
T HE INTEGRATION OF plant design and
laboratory was so successful that we see no
reason to return to our old system.
We are working on a new project for next
year, again involving local industry. This time,
we will arrange for the student groups to visit


The two courses complimented each
other appropriately, and all of our objectives
were met, at least to some degree.



the plant regularly and discuss their problems
with the practicing engineers and scientists. The
final report will be presented at the plant site.
Financial support from industry seems in the
offing.

REQUIREMENTS FOR SUCCESS

WE ENTHUSIASTICALLY recommend the
joint lab design approach. If you try it, you
might consider four points which we feel to be of
paramount importance:
* The cooperation of an accessible industry is essential.
The company should be willing to help provide ideas,
materials, and (within proprietary limits) information.
* A suitable problem must be chosen. If it is too old, all
the necessary information will be readily available in
the literature. If it is too new, it may be too "secret."
* A great deal of advance planning is necessary. The
faculty members in charge must familiarize themselves
with the process and with its problems. They must de-
velop a feel for the feasibility of the assignment.
Consider your equipment constraints in advance. The
project is unlikely to succeed if the students have to
wait for orders, shipments, and deliveries.

ACKNOWLEDGMENTS

T HE COOPERATION OF E. I. duPont deNe-
mours and Co., Old Hickory, Tennessee, is
gratefully acknowledged, particularly the help of
Mr. A. B. Alexander and Miss Martha Andrews.
Joint efforts of this sort make a real contribution
to the future of the profession.
Much of the equipment used in this project
was provided by the Olin Foundation.

REFERENCES
1. Perry, R. H., and Chilton, C. H. (eds), "Chemical
Engineer's Handbook" (5th Ed.), McGraw-Hill, 1973.
2. Peters, M. S., and Timmerhaus, K. D., "Plant Design
and Economics for Chemical Engineers (2nd Ed.),
McGraw-Hill, 1968.
3. Tomita, K., and Ida, H., Polymer, 14, 55 (1973).
4. Tomita, K., Polymer, 14, 50 (1973).
5. U. S. Patent 3,174,830 by A. Watzl et al. (to Vereinigte
Glanzstaff-Fabriken A. G.) (March 23, 1965).
6. Baker, T. S., Fisher, G. T., and Roth, J. A., J. ChE
Data, 9, 11 (1964).


WINTER 1975











PRELIMINARY APPRAISAL

OF A SELF-PACED LABORATORY


HOWARD F. RASE
University of Texas
Austin, Texas 78712


T HE SELF-PACED CONCEPT in education
has received the greatest attention in
standard courses which have traditionally been
taught by the lecture method. In the continuing
debate on the value of the self-paced approach
the most convincing disadvantages cited are the
lack of regular instructor contact and of group
interaction. Although these deficiencies can
theoretically be eliminated, they seldom are be-
cause the system inherently operates more smooth-
ly, but not necessarily for the student's good,
when such aspects are minimized. It has been in-
teresting, therefore, to discover that a self-paced
laboratory can combine the advantages of self-
paced instruction without the major disadvant-
ages, while at the same time making the labora-
tory an interesting and challenging experience.

THE TRADITIONAL ChE LAB
T HE TRADITIONAL LABORATORY in
chemical engineering usually involves a
number of set experiments which are repeated
each semester. These normally include experi-
ments in unit operations and other areas such as
reaction kinetics. In many cases the laboratory
has been made more interesting by adding special
projects which are never assigned more than once
and which are similar to technical service or de-
velopment problems soon to be encountered by
the young engineer in industry.* Invariably,
however, experiments and reporting periods are



The results of this effort were
astoundingly gratifying. The students
worked enthusiastically, with a level of
skill which indicated hours of planning and
thought seldom found in an undergraduate lab.


Howard F. Rase is the W. A. Cunningham Professor of Chemical
Engineering at the University of Texas. He was a process engineer
with Foster Wheeler Corporation and Dow Chemical Company before
joining the faculty at The University of Texas at Austin in 1952. He
has served as Chairman from 1963-1968. His researches are in catalysis
and process design in which areas he has written over fifty (50)
articles and three books.


scheduled so that the course is completed just be-
fore the final examination period as are typical
lecture courses. There is no incentive for working
harder and smarter in order to finish earlier.
This aspect of the laboratory experience bears
little resemblance to real-life situations where
time pressures are often great and where indeed
the professional is self-paced.

THE SELF-PACED LAB
W E DECIDED TO ATTEMPT a self-paced
laboratory based on the premise that since
the course requires a set number of experiments
and a major special project, students will find it
more stimulating to be allowed to complete the
course as rapidly as possible. Students were as-
signed the required set experiments along with a
special project at the beginning of the course. A
special lecture was given on organizing and exe-
cuting experiments, and methods for solving
technical-service and development type problems

*Chem. Engr., page 66, Sept. 8, 1969.


CHEMICAL ENGINEERING EDUCATION









TABLE 1
TYPICAL SET EXPERIMENTS
1. Batch reactor study of ethyl acetate spaonification
2. Batch distillation of selected binaries and scale-up
3. Operation of pilot-scale forced circulation evaporator
4. Study of major characteristics of fluidized beds
5. Operation of a tubular reactor


characterized by the special projects were de-
scribed. Typical set experiments and special
products used in the laboratory are summarized
in Tables 1 and 2.


TABLE 2
TYPICAL SPECIAL PROJECTS
1. Study of the mechanism of plugging in fixed beds
2. Osmotic drying of fruit
3. Optimum continuous production conditions for
compression molding
4. Purification of biuret
5. Purification of glycerine still bottoms
6. Removal of 4 ppm of chlorinated hydrocarbons
from air
7. Optimizing precoat and body-feed ratio of filteraid
in the filtration of a viscous mixture of alkylene
oxides



It has been interesting to discover that a
self paced lab can combine the advantages
of self paced instruction without the
major disadvantages, while making
the laboratory an interesting
and challenging experience.



RESULTS
T HE RESULTS OF THIS effort were astound-
ing and gratifying. The students worked en-
thusiastically and with a level of skill which in-
dicated hours of planning and thought seldom ob-
served in an undergraduate laboratory. The
healthy competition which was fostered by a
general desire to finish at a suggested early time
or earlier had several desirable side effects.
* It fostered a great deal of interest in all the projects
on the part of each group such that students learned
more and gained broader range conceptual insights on
problem solving.
* Because of the high level of interest and the strong de-
sire to complete the work, both the professor and his
teaching assistant were drawn into more frequent one-


on-one tutorial opportunities. The students were much
more strongly interested in probing meanings and
methods.
Innovation was much more prevalent in this atmosphere
created by the time pressure. Students were not only
innovative technically but also in their planning and
time management. The common loss of time experienced
in starting and stopping work soon prompted several
groups to schedule longer but fewer work periods. Other
groups found that two set experiments could be done
at the same time when one required long periods to
equilibriate. These highly desirable attributes seldom
flower in the traditional laboratory.


CONCLUSIONS

A SELF-PACED SENIOR laboratory in chemi-
cal engineering has many advantages as a
teaching tool for the development of competent
professionals. A successful course of this type re-
quires a great deal of planning by the professor,
procurement officer, and departmental mechanic
and electronic technician. Delays caused by the
establishment itself can be damaging to the zeal
of the young but eager learner. El



ChE Educator: FINLAYSON
(Continued from page 3.)

OUTSIDE INTERESTS

L IKE MANY WHO come to live in the Pacific
Northwest, Bruce and his family have grown
to love the out-of-doors. He bicycles to work, rain
or shine. Now that his children are old enough
(> 5), he and his family of three children and
one foster child have backpacked together in both
the Cascade and Olympic mountains. In the winter
all six members of the family take to skiing. Bruce
has also continued his interest in music, though
drums have given ground to the guitar. He and
Pat also enjoy attending the Seattle Symphony
concerts and plays, and for other relaxation
Bruce will occasionally read a mystery.

In addition to his dedication to his family, re-
search, and teaching Bruce is an integral part of
the Department and of the College of Engineer-
ing. He has been chairman of many committees
and now represents the College on the Faculty
Senate. All of us on the faculty are pleased and
proud to have Bruce among us. The future holds
great promise for him. D


WINTER 1975









REPORTING PRECISION OF EXPERIMENTAL DATA


KENNETH R. HALL
Texas A & M University
College Station, Texas 77843
DONALD J. KIRWAN and OTIS L. UPDIKE
University of Virginia
Charlottesville, Virginia 22901


SIMPLE CONCEPTS OFTEN receive the com-
ment, "but everyone knows that!" Un-
fortunately, everyone seldom includes all persons.
In particular, we feel this generalization applies
to one of the basic responsibilities of the scientific
community-reporting the precision of experi-
mental data. Many times in theses, dissertations
and even in technical papers this straightforward,
mathematically obvious exercise is either ignored
or applied improperly.
The concept of precision is precisely defined
and is a statistical quantity not to be confused
(though it frequently is) with the equally precise
concept of accuracy. Precision is a measure of
the experimental reproducibility, that is, of the
random errors associated with the apparatus and
operator. The accuracy is a measure of the abso-
lute quality of the data, that is, how closely the
data approximate the true values of the ob-
servables. We can calculate precision by standard
statistical techniques (and approximations), but
we must estimate accuracy based upon knowledge
of the apparatus, calibration against known
standards, and confidence in its operation.
The standard deviation is the preferred repre-
sentation of precision and is defined as the square
root of the variance of the data. For example, if z
is an observable, its variance is the expected value
of the square of the deviation between the ob-
served quantity and its expected value:

var (z) = <(z )2>


Assume we are collecting data which meet the
usually-satisfied continuity requirements allowing
z to be approximated by a Taylor series
truncated to first order,

z <> ( ) (x. )
i xx x i i


where the xi are the independent variables deter-
mining z. To obtain an estimate of the standard
deviation, square each side of equation (2) :


2
1 x


+ ( -z (x-) (x.-)
jli i i


(x. )
1 1


then take the expected value of the result (as-
suming the derivatives are exact) :

var(z) (--)x var(xi)
i 2ci 9i

S 1 1


j>i
(4)
The standard deviation of z, ao-, is simply the
square root of equation (4).
Unfortunately, we rarely have even an esti-
mate of cov (xi, xi). Fortunately, we seldom need
one. The covariance represents a correlation, or
interdependence, between the subject variables
(in this case xi, x,). The observables are usually
measured independently, therefore the covariance
is zero and the variance of z reduces to

var (z) (- --) var (x.)
ax x. -
1 1 1


Using equation (5) requires knowledge of z
as a function of the xi and of the variances of
the xi. The data themselves satisfy the first re-
quirement, although a more convenient situation
would be to have a mathematical function
z = z (x,, x, .) which can be differentiated. The


CHEMICAL ENGINEERING EDUCATION








variances of the xi are seldom available, but can
be replaced with estimated errors of the x1, E2i.
The equation for estimating the standard devia-
tion then becomes



1 x
(6)

An attractive and valid geometric model for
the additivity of variances results from consider-
ing z as uncertainly located in n-space, with the
uncertainty arising from the errors in the n in-
dependent variables, which combine orthogonally
if each independent variable acts along its own
coordinate of the space. (Correlations, in this
model, correspond to non-orthogonality of the
error-component vectors.)
Reviewing the assumptions involved in equa-
tion (6) :

* z can be approximated by a first-order
Taylor expansion;
errors in the independent variables, xi, are not
correlated;
variances of the independent variables may be
approximated by their apparent experimental
errors, Ei.
(Along with the third assumption, we caution
that there are occasional cases where badly
skewed or bimodal error distributions make
simple addition of the variances, or second mo-
ments, inadequate.)
A common and less defensible technique for
assigning precision to data is to use the deriva-
tives themselves as weighting factors. Assuming
z = z(xX, x2 .),

dz = (Z.-) dx.

(7)

dz is assumed to be o-z and the dxi are all replaced
with e1. Of course, the partial derivatives and
E, can be negative; so the absolute values are
commonly used:


Tz E <(xz)
1 X.
1


1i


(8)
Equation (8) is often said to provide the "maxi-
mum error estimate." This statement has no valid
theoretical basis; a defensible worst-case error
estimate would actually be 3o-z from equation (6).
Furthermore, when absolute values are used,
physical significance becomes obscure, and geo-
metrical significance is destroyed. Effectively,
equation (8) contains all the assumptions of equa-
tion (6) plus one more-that the square root of
a sum is the sum of the square roots. This latter
assumption is not generally valid-

V4 9 16 29 = 5.4
2+3+4 = 9
Now consider some examples, the first involv-
ing the precision in measuring liquid composi-
tion by interferometry. Kirwan (1967) provides
the difference between interface composition and
that of the bulk liquid


y0 ( n)


where AN is the fringe shift at the interface, Xo
is the wavelength of the light, t is the thickness
of the optical wedge and n is the refractive index.
Kirwan also reports that the percentage errors in
AN, Xo, t and (Dn/Dy)T are respectively 20%,
<0.1,% 10% and 5%. In this case (when all ob-
servables appear as multiples in the equation), it
is convenient to divide both sides of equation (6)
by the dependent variable:

L E j ( 12 jo.5

(10)
Now percentage errors can be substituted direct-
ly, yielding o-y/Y = 0.23. From equation (8), the
value would be o-,/Y 0.35.
A second example involves a PvT experiment.
For illustration, assume a van der Waals gas with
the properties T =- 356.37K, P, = 3.700 MPa,
a = 1.000 X 10-6, b 1.000 X 10-4 and the gas


WINTER 1975


Many times, in theses dissertations and even technical papers, this straightforward
exercise (of reporting precision) is either ignored or applied improperly.










Otis L. Updike, Professor of Chemical and of Biomedical Engineer-
ing at the University of Virginia, received the B. Ch. E. from Virginia
and the Ph.D (1944) from the University of Illinois; he also has held
an NSF Science Faculty Fellowship at Caltech. In industry, chiefly with
Westvaco Chemical (now part of FMC) and Oak Ridge National
Laboratory, he worked in process development, design, and systems
process control. With interests, and system identification in both
the process and the biomedical fields, he is a member of AIChE, BmES,
ISA, IEEE, SCS, AAMI, and ASEE.


Kenneth R. Hall received his B. S. from Tulsa University, M. S.
from U. of California at Berkeley and Ph.D. from the University of


constant, R = 8.3143 X 10-6 MPa m3/mol K. We
desire the precision in determining the volume at
360.82K and 100.OMPa. The following equation
is applicable:
RT a
v-b
Note that the observables do not appear as simple
multiples, so an equation similar to equation (10)
does not exist. Using ET = 0.01K and e, = 0.01
MPa (both reasonable values for these measure-
ments), equation (6) estimates o- = 1.3 X 10-9,
or 0.0011, while equation (8) produces o-,=1.7 X
10- on 0.0015%. These precisions are reasonable
because the gas is in a low compressibility region.
Our third example concerns measurement of
oxygen concentration with the Westinghouse con-
centration-cell sensor (Updike, Dammann, and
Bowers, 1968). The response of this device is
Nernstian, and may be described by the relation
SE = In frf
nF f02
(12)
where AE is the cell output voltage; R and F are
the gas constant and Faraday's constant; T is
absolute temperature of the zirconia electrolyte;
n is the number of electrons transferred in the
electrode reaction; and f is the fugacity of oxygen
in reference and sample stream, as indicated by
the subscripts. Equation (14) can be rearranged
conveniently, with substitutions for the fugacities,
to the form

2 ( sap 'samp nFiE
Y02 Yref Pref I\ fef RT

13)
= Yref a e
(13a)
where Psm5 and Pref are total pressures in the
sample and reference regions; 4samr and Oref are


Oklahoma. He held a NATO Post-doctoral fellowship in Belgium and
had industrial experience with Chemshare, Inc. and Amoco Produc-
tion Research. He taught at the University of Virginia for a number
of years and is currently on the Chemical Engineering Faculty at
Texas A & M University. His primary research interest is in the thermo-
dynamic properties of fluids.

Donald J. Kirwan received his B. S. degree from Illinois Institute
of Technology and the M. S. and Ph.D. degrees from the University
of Delaware, all in Chemical Engineering. He worked at the Mon-
santo Company in St. Louis for three years prior to joining the
faculty of the University of Virginia. His research interests are in
the areas of mass transfer, crystallization and enzyme engineering.


the corresponding fugacity coefficients; and a, P3
and y are introduced for convenience as shown in
form (13a).
For the factors in equation (13a), the un-
certainties are estimated as
e,- = 0.001, e, = 0.002, eC = 0.001, EAE
rJf
= 0.0001 V, and Er = 3K (at 1123K).
(The pressure and fugacity ratios are handled
as single variables because errors in these terms
are, by design compensating.) The expression for
the estimated standard deviation results from
differentiation of equation (13) and substitution
in equation (6) ; the derivatives are conveniently
developed from the concise form 13a). Substitu-
tion of these derivatives into equation (6) yields

-0 )20 + --, + 1 + 1 f F-. 1

(14)
Thus, at yo., = 0.500, and AE = 0.0210 volts
r -6i '5
y- (5.7 + 1.0 + 0.3 + 4.3 + 1.3)x 10 = 0.0035
This third example shows several points:
(a) the exponential factor does not allow the
simple combination of percentage errors which
was possible in the first case; (b) the independent
variables contribute unequally to the overall un-
certainty, and equation (6) displays clearly the
minor contribution of uncertainties in /j (the
fugacity ratio) ; (c) with more error contributors,
the ratio between the more defensible estimate of
equation (6) and that of equation (8) has in-
creased; (d) expected correlations were handled
by using ratios of variables in factors a and (3;
and (e) because of the exponential form, the
error level changes with y0o and y,.ef-arguing for
care in the choice of the reference gas concentra-
tion when this sensor is used.
(Continued on page 30.)


CHEMICAL ENGINEERING EDUCATION









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The fire fighter that looks
out of place is the pair of paja-
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up to size 6X must be made
flame-retardant.
And these pajamas are made
of 100% Dynel modacrylic, a


flame-retardant fiber created by
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When exposed to fire, properly
constructed fabric of Dynel
does a very sensible thing. It
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And if a flame should reach
it, it extinguishes itself as soon
as the flame is removed.
Dynel has a lot more going
for it. It's soft, non-allergenic,
durable, colorfast, mothproof.
So you're likely to find this
versatile fiber in all sorts of


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tents, paint rollers.
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An Equal Opportunity Employer










SOME SIMPLE EXPERIMENTS


FOR FIRST YEAR STUDENTS


A. M. GERRARD
Teesside Polytechnic
Middlesbrough
Cleveland County, England


F IRST YEAR STUDENTS of the Polytechnic's
sandwich (co-operative) BSc in Chemical
Engineering are taught transport phenomena
[1, 2] and some elements of process design. This
early introduction to Chemical Engineering
fundamentals allows them to make a real contri-
bution when they join industry for four months
of project work after completing one academic
year of study. This situation has led to the de-
velopment of some simple experiments to suggest
to the embryo engineer that some parallels do
exist between the, at first, apparently dissimilar
processes of heat, mass and momentum transfer.
These experiments are carried out in the first few
weeks of the term, often before the subjects are
handled formally in class.
The common link we chose was the simple first
order differential equation:


dx= ky (1)
indeed all the three systems to be studied can be
modelled by this equation.

CAPILLARY FLOW

In the first experiment, the rate of drainage
of a Newtonian fluid through a capillary is
measured against time. The vertical reservoir is
filled with water, say, and allowed to drain, the
height of the interface being measured at given
time intervals. A mass balance over the system
coupled with hydrodynamic considerations yields
the well known expression:


dL = -Kt, where K = 12d P(
dt 128ZAi (2)
Integration then gives:

H = Ho exp (-Kt) (3)
which is the required model of the system.
To obtain the previous expressions the student
must know the Hagen-Poiseuille equation and


TABLE 1


SUMMARY OF EXPERIMENTS


Drainage through
Experiment Capillary


Cooling of Glycerol


Dissolution of
benzoic acid


Momentum transfer
Transient mass
balance and steady
state force balance
Laminar flow

Allowance for
entry effects


Heat transfer
Transient heat
balance

Natural convection

Allowance for
variation in heat
transfer coefficient


Mass transfer
Transient mass
balance

Whitman's film
theory
Effect of agitator
speed on mass
transfer


Use of log-linear graph paper, normalized plots and curve
sketching from the basic model.
Treat results using regression analysis.


CHEMICAL ENGINEERING EDUCATION


Subject
Method of
Modelling


Underlying
Theory
Extension of
basic
experiment
Handling of
Results










A A



H


/ d



FIGURE 1. Flow through a capillary

hence have an understanding of laminar flow to-
gether with the definitions and use of viscosity,
shear stress and strain in order that the equation
can be derived. As soon as the model has been
formulated the student is asked to sketch the H-t
curve, noting that it will tend to an asymptote as
t- oo. It is also worthwhile demonstrating that
the curve has no maximum or minimum by the
classical calculus approach. These points are
generally brought out in an extended 'viva' during
the laboratory session. The students, working in
pairs, have already produced a short planning re-
port prior to their carrying out the experiment;
this ensures that they are well prepared for the
cross-examination which follows!
As soon as the experiment is concluded, the
results can be compared with the theoretical pre-
dictions. Thus, the predicted and experimentally
determined values of K can be computed, the
latter being facilitated by the use of semi-log
paper. Then a discussion of errors can be made,
indeed the log (H/Ho) against t curve can be cal-
culated using regression analysis [3], the more
able student can also introduce here the idea of
entry effects and attempt to make some allowance
for them. If 'the essence of science is prediction'
then this experiment is a fine example.


the system. Many student's first attempt at this
involves defining the system over which the tran-
sient mass balance is to be carried out as the solid
benzoic acid plus the water-this approach does
not allow much progress to be made-hence em-
phasizing the care needed in choosing control
volumes! The simplest differential model is, of
course:
V dc
dt = KLA (Cs-) (4)
its integration being straight forward, again
semi-logarithmic paper allows a straight line
representation of the experimental data. The dis-
cussion of errors centres around the importance
of the area of the cylinder and the solution volume
changing slightly throughout the proceedings, A
useful-and often neglected-check on the titra-
tions is the measurement of the overall weight
loss of the benzoic acid block. As before, the basic
experiment can be extended, this time by investi-
gating the influence of agitator speed N on the
mass transfer coefficient, K, where:

L 0 6 (5)

to demonstrate this conveniently the student is
introduced to the use of log-log paper, perhaps
for the first time.

COOLING
T HIS TRIO OF EXPERIMENTS is completed
with a study of heat transfer. A lagged beak-
er full of a hot non-volatile liquid, glycerol say, is


DISSOLUTION


T HE NEXT EXPERIMENT introduces some
simple ideas in mass transfer. A cylinder of
some sparingly soluble solid is dissolved in an ap-
propriate fluid in a stirred flask. (We use benzoic
acid in water, the solution being sampled at
regular intervals, say 5cc every 15 minutes, and
titrated against 0.01 N caustic soda). Some
familiarity with Whitman's theory of interphase
mass transfer is needed prior to the modelling of


Mr. Gerrard graduated in Chemical Engineering from Edinburgh
University and then worked in the Research and Development De-
partment of Cadbury-Schweppes. Since joining his present post his
technical interests have included particulate technology, process
economics and optimisation together with the development of the
undergraduate laboratories.


WINTER 1975









allowed to cool in a draught proof perspex case,
the principal mode of heat loss being natural con-
vection. The temperature of the fluid and the sur-
roundings are noted for an hour or two. Again
a transient (heat) balance yields the desired
model:--
-MCp dF = hA (0-0a) (6)
dt
whose integrated form can be represented by a
straight line on log-linear graph paper. An exten-
sion of the basic theory which allows for the de-
pendence of heat transfer coefficient with
temperature difference where:
0.25 (7)
h (0-0a) (7)
can also be made.
All of the experiments can be repeated using
different initial heights, concentrations and
temperatures respectively. The results then for,
say, all the fluid flow experiments lie on the same
line if the normalized ordinate (H/Ho) is used.
Indeed if the normalized abscissa (Kt) is also
used then the results from different diameter
capillary experiments also can be reduced to a
one line representation. This dimensionless
plotting is yet another important concept for the
student to grasp.

CONCLUSION
W E HAVE FOUND THAT these three inex-
pensive and simple experiments have aided
our student's comprehension of, and belief in, the
analogous behaviour of the various forms of trans-
port phenomena. Equally importantly, the writing
of full engineering reports on their findings pro-
vides useful training prior to their early in-
dustrial baptism. Perhaps as a postscript we can
also mention two further experiments which are
given to our first year men which again are
governed by:
dy ky
ky
dx (8)
these being the transient mass balance over a
stirred tank containing acid diluted with water
and a rig on the rates of batch sieving.
ACKNOWLEDGMENT
The author is happy to acknowledge the help-
ful comments of his colleague C.J. Liddle in the
development of the experiments described above.

NOTATION
A Area
C', C (Saturation), concentration
Cp Specific heat


d
g
Ho, H
h
K, k
KI.
1

M
N
t
V
a i, 0
P
/3


Capillary diameter
Acceleration due to gravity
(Original), height
Heat transfer coefficient
Constants
Mass transfer coefficient
length of capillary
Mass
Rotational speed
Time
Volume
(Ambient, initial), temperature
Density
Viscosity


REFERENCES
1. Bird R. B., Steward W. E., Lightfoot E. N., "Trans-
port Phenomena," J. Wiley, 1960.
2. Welty J. R., Wicks E. C., Wilson R. E., "Funda-
mentals of Momentum, Heat and Mass Transfer,"
J. Wiley, 1969.
3. Chemical Engineering Laboratory Manual, Teesside
Polytechnic, September 1973.

PRECISION: Hall et al.
(Continued from page 26.)
Equation (8) approximates o-r as greater
than the more valid estimate of equation (6). The
difference depends on the number of error-con-
tributing independent variables and on the deriva-
tive-weighted contributions of each. For the
common case where three or four factors each
contribute comparably to the overall variance, the
linearly-additive equation (8) produces estimates
not more than twice the orthogonally-additive
estimate of equation (6) ; for only one major con-
tributor, results are essentially the same. Since
the calculation required is only negligibly greater,
the theoretically defensible equation (6) should
always be used.
We hasten to add that nothing new is present-
ed here. Equation (6) is available in many
references, for example Mickley, Sherwood and
Reed (1957) ; but we find that an overwhelming
majority of students-and even colleagues!- use
equation (8). This communication is an attempt
to advocate the more rigorous, well documented,
largely neglected approach. -
REFERENCES
Kirwan, D. J., "Crystallization Kinetics of Pure and Binary
Melts," Ph.D. Dissertation, University of Delaware
(1967).
Mickley, H.S., T.K. Sherwood, and C.E. Reed, "Applied
Mathematics in Chemical Engineering," 2nd ed., Mc-
Graw-Hill (1957).
Updike, O.L., J.F., Dammann, and D.L. Bowers, "Per-
formance of a Fast-Response Respiratory Oxygen
Sensor," Proc. Rocky Mtn. Bioeng. Sympos. (Denver,
1968), 109-116.


CHEMICAL ENGINEERING EDUCATION









Pral J1news


SM





In Memorium
JACOB JORNE
Wayne State University
Detroit, Michigan 48202
W ITH THE SUDDEN DEATH of Professor Julius
L. Jackson on July 5, 1974 the scientific
community lost a productive, stimulating and
wonderful colleague. Dr. Jackson was buried in
the special memorial plot at the Weitzmann In-
stitute of Sciences, Rehovot, Israel, where he was
a visiting scientist for the summer. Dr. Jackson
served from 1969 to 1974 as the Chairman of the
Department of Chemical Engineering and
Material Sciences, Wayne State University, a
post he resigned this June in order to devote more
time to teaching and research. He recently served
as a member of the Publications Board of CEE.
He is survived by his wife, three sons and a
daughter.
Professor Jackson was born on 9 November,
1924, in New York City and received degrees in
Physics at Brooklyn College, Princeton, and New
York University, where he earned his Ph.D. in
1950. He served as a visiting professor at the
State University of Iowa prior to joining the
Applied Physics Laboratory of the John Hopkins
University as a research physicist in 1951. He
also served at the Office of Naval Research and in
1956 he became a research physicist at the Nation-
al Bureau of Standards where he worked in the
Free Radicals Program and in the Statistical
Physics Section. In 1961 he joined Howard Uni-
versity as Professor of Physics.


A memorial Festschrift is being prepared, a
memorial lecture series will be held at Wayne
State University, and a fund for the education of
his children has been established. Contributions
to any of these should be sent to Julius Jackson
Memorial Fund, Wayne Fund, Detroit, Michi-
gan 48202. Jacob Jorne, Wayne State University,
Detroit, Mich.



s"I book reviews

Polymer Materials Science, by Jerold M. Schultz,
Prentice-Hall, Inc., Englewood Cliffs, N. J. 1974.
Reviewed by A. T. DiBenedetto, U. of Connecticut;
Storrs, Conn.

p OLYMER MATERIALS SCIENCE is a text-
book for senior level or first year graduate
students majoring in chemical engineering,
physics or materials science. It presupposes a
good background in physical chemistry, crystal-
lography, solid mechanics and mathematics. The
text is divided into three sections. The first four
chapters cover the science of polymer crystals
in a rather unique way, emphasizing the experi-
mental techniques of characterizing polymer
crystals and the interpretation of such measure-
ments. The second section is a very brief two
chapters on polymerization and molecular weight
distribution, included to describe the character of
polymeric chains. The third section is a loosely
connected set of five chapters on the properties
of polymeric materials. Some of the material in
these latter chapters are analytic descriptions of
the relationships between structure and proper-
ties (e. g. rubber elasticity) while the rest is by
necessity more qualitative (e. g. the mechanics
of semi-crystalline polymers).
Like most polymer texts that have been
written in recent years, it reflects a point of view
by the author of what should be in an introduc-
tory course in polymeric materials. Those who
feel that students should be exposed first to the
technology of polymers will not want to use this
book as a text. There is no information here on
plastics fabrication and end use. Those who feel
that polymer synthesis and the control of proper-
ties through chemical reaction kinetics deserves
at least equal time with structure-property rela-
tions, also will not want to use this book as a text.
(Continued on page 48.)


WINTER 1975








fi classroom


AN INTRODUCTORY DESIGN COURSE

FOR ENGINEERING FRESHMEN


GORDON R. YOUNGQUIST
Clarkson College of Technology
Potsdam, New York 13676

INTRODUCING BEGINNING ENGINEERING
students to the profession in a meaningful way
has long been a problem. At Clarkson College of
Technology a variety of techniques have been
tried, many meeting with a singular lack of real
success. The methods used have ranged from in-
formal orientation sessions to design to nothing
at all. The long range effects of these attempts
are difficult to measure, but one can be reasonably
certain that the engineering profession loses a
significant number of potentially productive mem-
bers when capable students are "turned off" by
their first exposures to engineering in college.
During the 1969-70 academic year, Clarkson's
Engineering School faculty completed a major
revision of its undergraduate curricula. These
curricula provide for a common Freshman pro-
gram for all engineering students including a two
course sequence (3 semester credits each) in
engineering taught jointly by faculty from each
department. The first of these, titled "Introduc-
tion to Engineering," is devoted primarily to de-
veloping skills in engineering graphics and digital
computing as a means of solving engineering prob-
lems. Some orientation to engineering and its
major branches is provided by lectures on topics
related to engineering design, the engineering
profession, or the relationship of engineering to
society. The second course, titled "Introduction to
Complex Design," is much more loosely structured
than the first. Depending on the faculty involved,
the course has been conducted in a wide variety of
ways but generally involving a design project of
one sort or another. Typically, near the end of the
first course engineering faculty members submit
project descriptions to the students who are asked
to indicate their preferences. Students are then
assigned to sections for the second course, taking
into account preferences and number limitations
imposed by the nature of the project.


What follows will describe the methods that I
used in teaching a section of "Introduction to
Complex Design" each of the past two years.
Centered about the design of a chemical plant, the
course content and organization will be given in
some detail and some measure of the students'
response as well as my reactions to the course will
be provided. Hopefully the information provided
will be of some value to those teaching or planning
a Freshman engineering course.

COURSE OBJECTIVES
I MUST CONFESS THAT I went into the
course the first time with some trepidation. It
never has been entirely clear to me just what
such a Freshman engineering course should con-
sist of. Broadly, the engineering school agreed
that the course should provide an introduction to
the engineering profession through a design ex-
perience. However, no specific guidelines as to
content or structure existed. Moreover, I had
never taught Freshmen and therefore had
relatively little insight into the kinds of problems
they could handle.


Gordon Youngquist received his BS from the University of Min-
nesota and his MS and PhD from the University of Illinois. Since
1962 he has been at Clarkson College of Technology where his
teaching and research interests are in reactor analysis, crystallization
and porous media.


CHEMICAL ENGINEERING EDUCATION









I felt that the course should somehow intro-
duce the student to a variety of engineering ac-
tivities, hopefully in such a way as to motivate
him to continue in engineering and to provide in-
sight into his future course of study and career.
More specifically, the following objectives
evolved:*

1. To provide experience at defining problems.
Nearly all of the problems students do have been
defined for them by someone else. Consider typical
textbook problems in science or engineering, for
example. A student's candid response to some prob-
lems he was confronted with in this course: "How
can I give an answer when I don't know what the
question is?"
2. To provide some introduction to the various aspects
of engineering design.
Emphasis was placed on the distinction and inter-
relationships between process design and equipment
design and also the important role of economics.
3. To provide experience at working with and for others
on a long term problem of broad scope.
Most of the work that students have done at this
point has been on short, well-defined problems that
they have completed by themselves. They have had
little experience at planning work on a long term
problem which requires the joint efforts of several
individuals.
4. To provide some experience at decision making.
Few engineering problems have but one solution!
5. To provide a means of applying accumulated back-
ground to completely new problems.
6. To provide experience at technical report presenta-
tion, both written and oral.
7. To provide experience at evaluating the work of
others.

COURSE IMPLEMENTATION

TO ACHIEVE THESE OBJECTIVES, I de-
cided to have the class do a chemical plant
design using a format not unlike the one often
used for our Senior design course. Table I pro-
vides general information about the staffing and
structure of the course. The first four weeks of
the course were devoted to relatively short, in-
troductory problems The next eight weeks were
spent on the design of a chemical plant. The final
two weeks were devoted to evaluation of written
design reports by the students themselves and to
oral presentations by the students. The class met
twice each week for two periods each day using
two adjoining classrooms. These were standard
classrooms with movable chairs, each accommo-
*Evolved is a most accurate description here. Some of
these I had in mind before the course started. Others
developed as the course progressed.


dating about 50 students. In 1972, I had six and
in 1973, eight teaching assistants working with
me. The assistants, all undergraduate chemical
engineers, were allowed 1 academic credit and



Students who took the course had, early
in their course of study, a broad range of
experience and exposure to engineering
that our typical student has never had in the past.



given a very modest stipend for their participa-
tion in the course.
The initial four week period served to orient
the student's thinking toward the solution of
engineering problems and to develop certain prob-
lem solving skills that they would need later in
the semester. Typically, the first half hour or 45
minutes of the class was devoted to lecture-dis-
cussion of a problem. During the remainder of
the class period, the students divided into 5 or 6
man groups to pursue the problem further

TABLE 1

STAFFING AND STRUCTURE

Instructor: G.R. Youngquist, Associate Professor of
Chemical Engineering.
Assistants: One undergraduate assistant for each 6
students. These were juniors or seniors
in Chemical Engineering.
Students: All were Freshmen. In 1972, 34 students
and in 1973, 42 students, took the course.
Of these about 2/3 were intending to be
Chemical Engineers, a few were intending
to be Civil or Mechanical Engineers, and
the rest were undecided at this point.
Classrooms: Used two adjoining standard classrooms.
Schedule: Class met two days per week, each day for
two 50 minute class periods.
Overall The semester was fourteen weeks long,
format: divided as follows:
4 weeks-Introductory problems covering
some principles of material and
energy balances. Some lectures,
some group activity, some in-
dividual activity.
8 weeks-Plant design project by student
groups of 5 to 6 culminating a
written design report.
1 week Student evaluation of written de-
sign reports
1 week Oral presentations of designs;
award made for best presenta-
tion.


WINTER 1975










Clarksen's curricula has a two semester common freshman program taught jointly by faculty
from each department the first is devoted to orientation to engineering,
engineering graphics and digital computing the second involves
a design project of some sort.


through discussion and analysis. Three or four
groups worked in each classroom to avoid con-
gestion. One assistant was assigned to each group
to answer questions, to stimulate discussion if
necessary, and to provide general guidance. I
circulated from group to group to provide addi-
tional assistance. In some cases, this activity cul-
minated in a homework assignment to be sub-
mitted by individual students.
The basic subject areas introduced during this
time were only two: energy conservation and
mass conservation. Generally I started with an
ill-defined problem and worked towards a well-
defined problem which could be made quantitative.
For example, on the first day of class I asked
the students to "design a system which could be
used to heat 10,000 gallons of a solvent from am-
bient temperature to 100C." The problem state-
ment was made deliberately vague to cause them
to ask a large number of questions, the answers
to which would serve to define the problem. The
students worked on the problem in groups,
making up a list of such questions, and also de-
veloping a number of alternative ways that could
be used. All of the groups considered batch-wise
steam heating as an alternative, placing the sol-
vent in a tank with an internal heating coil. For
the next class period, I restated the problem pro-
viding answers to many of the questions they had
posed. We then looked at quantitative aspects of
the problem, asking in particular how one might
determine the required size of the steam coil. This
led naturally to a discussion of the factors which
influence the rate of heat transfer. The notions
of the temperature driving force and the overall
heat transfer coefficient were introduced. From
these, we developed an unsteady state energy
balance for the system making use of the defini-
tion of the derivative to arrive at an appropriate
differential equation. Then, for a group activity
I asked them to solve the differential equation and
to calculate the required heat transfer area. Al-
though they had no prior exposure to differential
equations, they quickly caught on to separation
of variables and recognized how to solve the re-


sult either analytically or numerically. Following
this, I introduced the log-mean temperature
difference, albeit in the context of a batch system.
Subsequently, I asked the students how the heat
exchange system might be made continuous. Of
course, they first suggested using the tank of the
batch system with continuous flow. We discussed
the merits of this suggestion and with a little bit
of prodding they soon arrived at the concepts of
double pipe and tube and shell exchangers. I
brought a small tube and shell exchanger to class
for their inspection. The students found this heat
exchange problem very satisfying. Among other
things, it was easy for them to visualize; they
could use their intuitive skills readily; they saw
how the mathematics they were studying could
be applied to a practical problem; and it revealed
the broad implications of batch versus continuous
systems. Above all, they got some feel for the im-
portance of defining a problem and using what
they already know to solve a problem they had
never seen before.
From here, we went on to look at a couple
of elementary mass balance problems involving
chemical reactions, then to combined mass and
energy balances (adiabatic flame temperatures,
e.g.), ending the four week period with a qualita-
tive discussion of rates of chemical reactions and
the characteristics of various types of chemical
reactors.
At times when they were struggling with the
definition of a problem, the students were quite
frustrated. In this respect, I tried to emphasize
strongly that adequately defining a problem often
is the most difficult part of finding a solution. I
was continually amazed at the students' ability to
use intuitive reasoning-much better than seniors,
I often felt. They were adept at generating sound
ideas, both for processes and equipment, and were
especially sensitive to the economic implications
of their ideas. The latter I found especially
pleasing, the importance of money in design arose
quite spontaneously throughout.


CHEMICAL ENGINEERING EDUCATION










ON TO PLANT DESIGN

T HE NEXT EIGHT WEEKS of the semester
were devoted to the design of a chemical
plant. At the beginning of this period, I asked
the class to divide themselves into 5 or 6 man
engineering "companies," each selecting their
own chief engineer. One teaching assistant was
assigned permanently to each company as a
technical consultant. Half of the companies, each
doing its own design, designed a plant for the wet
oxidation of sludge from a waste treatment plant
while the other half designed a plant for convert-
ing the sludge to oil. Table 2 shows the letter
which was used as the problem assignment. These
two processes were selected because of their
obvious relevance, because a reasonable amount of
background information was available, and be-
cause the problems were sufficiently broad in
scope that the interests of potential Civil and
Mechanical as well as Chemical Engineers could
be served. Furthermore, I have some related re-

TABLE 2
DESIGN PROBLEM STATEMENT
Integral Chemical Company
209 Peyton Hall
Potsdam, New York 13676
February 6. 1973
Consultants, Inc.
342 Snell Hall
Potsdam, New York 13676
Gentlemen:
Our chemical processing facility in Potsdam has a
waste treatment plant which produces 300,000 gallons of
effluent per day. The effluent is about 3% by weight solids
(the rest is water) and the solids are 75% organic. The
composition of the organic material can be represented
by the empirical formula C11sH1700oN17P.
At present we are dewatering the effluent by vacuum
filtration to 25% solids and the solids are incinerated
using fuel oil as an auxiliary fuel. The residual ash is
landfilled. This process costs us about $20 per ton of dry
solids. The filtration step has been no end of trouble to us,
however, since to be efficient incineration requires rather
close regulation of the water content and our filters have
been difficult to control. In addition, both the State and
Federal Environmental Protection Agencies are putting
pressure on us to reduce both particulate and chemical
emissions from our incinerator stacks.
As a result, we have been looking for alternatives to
incineration for disposal of our wastes. Two such methods
which have come to our attention recently and which
appear potentially attractive for our purposes are: 1) wet
oxidation (i.e., the Zimpro process) and 2) conversion of
the wastes to oil.
Some of the possible advantages we see for these
processes are the following. In the wet oxidation process,


the organic may be more or less completely oxidized to
carbon dioxide and water in the presence of liquid water
and air. With liquid water present fly ash is no problem
and many of the oxidation products will form water
soluble salts. Filtration of the effluent possibly may be
unnecessary. Also, it might be possible to generate elec-
trical power by expanding the high pressure, high
temperature gases which result from the process through
a turbine.
In conversion to oil, the organic are reacted in the
presence of carbon monoxide and liquid water to produce
fuel oil. This oil may be especially valuable to us in light
of recent shortages. As with the wet oxidation process,
the emissions problems attendant to incineration should
be largely checked.
On the negative side, with either of these processes
we will still have to meet the local pollution standards
for both our off gases and our waste water. The residual
insoluble solids will likely have to be separated and land-
filled. In addition, since both processes require moderate
reactor pressures and temperatures, capital costs for
plant installation may be high.
Since these processes do look reasonably attractive to
us, we would like your firm to do a plant design for one
of them. This design should provide us with the basis
for determining the advisability of proceeding to the final
design and construction stage. As a minimum it should
include reasonably complete process and equipment speci-
fications along with your best estimates of capital and
operating costs. We require that your final design report
be submitted to us by April 19, 1973. You should also be
prepared to make an oral presentation to our staff on
May 1, 1973.
Very truly yours,
I. N. Tegral, President

search interests and the two processes are quite
similar so I would not spread myself too thin in
terms of background. At the outset, I provided
each of the groups with a few pertinent papers
about each process. Each group organized its
activities as it saw fit. I asked for very brief week-
ly activity reports from each company and two
progress reports in addition to a final written
design report, but beyond this imposed no specific
structure. No formal lectures were given during
the project period. I did expect the students to
show up for each scheduled class, so that they



The course should provide an introduction
to the engineering profession through a
design experience and motivate
the student to continue in engineering
and to provide insight into his future
course of study and career.


WINTER 1975








could consult with the assistants, myself and each
other. Most of the companies stumbled around
for two to three weeks trying to get themselves
organized effectively and, subsequently, trying to
define the problem. I did not interfere with this,
except to make suggestions when asked. It took
the students a while to recognize the value of a
process flowsheet, but once this was done they
were off and running. To assist the companies in
getting started with the necessary material and
energy balance calculations, I made up two lec-
tures on cassette tapes. This proved quite effective.
In addition, I regularly brought to class references
such as Perry's Handbook, Popper's Handbook
for Cost Estimation, Handbook of Chemistry and
Physics, and Peters and Timmerhaus Plant De-
sign and Economics. Especially towards the end
of the project, these were used heavily. The stu-
dents often had considerable difficulty in using
library sources, primarily because most of the
potentially useful texts were written in language
that was too advanced.
The companies organized themselves in a
variety of ways, but I am certain that all came
away from the design project with a good ap-
preciation of the difficulties of working with and
for people in a situation where crossflow of in-
formation is vital. In most cases, the company
engineers became "experts" in different aspects
of the process, sharing their knowledge in dis-


The competitive spirit which pervaded during
this time was tremendous companies
went all out to make good presentations .
Students were able to ask penetrating
questions and discussions following
were very spirited.


cussions both in and out of class. The assistants
were quite effective in working with the
companies, developing good rapport with their
groups. As in the first four weeks, I circulated
from company to company during-class meetings
providing guidance wherever it was most needed.
At the start of the design project, most of the
students were a bit overwhelmed, feeling that a
plant design was more than they could handle.
By the end, most were surprised and pleased at
how far they had progressed. (Frankly, so
was I!). Their final written reports were sub-
mitted on time, were remarkably complete, and


generally of high quality. The reports reflected
some technical naivete, as you might expect, but
I felt showed considerable imagination and
creativity in treating some genuinely complex
engineering problems.

FINAL REPORTS
ON THE DAY THAT the final reports were
submitted, I asked each student to evaluate
the members of his company, without identifying
himself. An evaluation form was provided for
this purpose. Many of the students commented
later that they did not like this peer evaluation,
but I felt that they responded conscientiously. At
this same time, I also requested a course evalua-
tion by written response to four questions. The
results were very interesting and will be present-
ed later.
In class during the week following submission
of the final reports, each company read and
evaluated the written reports of two other
companies. Identifying features of the reports
were removed so that the companies did not know
whose report they were evaluating. The students
took this seriously and did a good job of construc-
tive criticism. I believe they found this activity
very revealing, for it demonstrated the importance
of good written communication and also gave
them the opportunity to see in detail what ap-
proaches other students took in solving the design
problems.
The final week was devoted to presentation
of oral reports on their design work. Four judges
(a faculty member, a graduate student, a senior,
and a freshman not involved with this section of
the course) were asked to evaluate the presenta-
tion and an award was made for the best report.
The competitive spirit which pervaded during
this time was tremendous, and the companies
went all out to make good presentations. Because
they all had worked on substantially the same
design problem, the students were able to ask
penetrating questions and the discussions which
followed each presentation were very spirited.
For the most part, I tried to play down the
importance of grades in the course. No examina-
tions were given. A few homework assignments
at the beginning of the course were collected and
graded, but these were not considered at all in
determining final grades. Final written reports
and oral reports were given a letter grade, but
these were considered as collective grades for the


CHEMICAL ENGINEERING EDUCATION









company. To determine grades for individuals,
I relied on 1) the peer evaluation mentioned
above, 2) evaluations by the assistants, and 3)
my personal evaluations as they developed over
the semester. Generally I looked for such qualities
as leadership, creativity, analytical ability, re-
liability, cooperation and effort by the students.
Since both the assistants and I worked closely


Students found their design project challenging
and realistic engineering they liked
the relatively flexible and informal
organization of the course. They
discovered engineering can be a lot
of work and that information gathering
is a significant part of that work.


with the students, it was relatively easy to deter-
mine which students knew the various aspects of
the problems, which were leaders, and so on. The
three evaluations cited above were remarkably
consistent, and I have full confidence that the
grades assigned were fair and justified. Con-
sidering the nature of the course, a pass-fail
grading system may have been more appropriate.

COURSE EVALUATION

EVALUATING A COURSE is never very easy.
The standard evaluation forms that one often
uses for lecture courses are inappropriate for a
course of this type, so I decided to ask the students
for written responses to four questions. These
were:
1) What aspects of the course did you like
the best? 2) What aspects of the course did you
like the least? 3) What are your chief criticisms
of the course? Do you have any suggestions for
improving it? 4) Has the course encouraged you
to continue in engineering or discouraged you
from doing so? Why?
The students responded conscientiously with
some very candid, meaningful, and interesting
comments. These are too lengthy to reproduce
here, but interested readers may obtain copies
typed exactly as they were written by contacting
the author directly. Table 3 briefly summarizes
the responses. It is clear that the students found
their design project to be challenging and realistic
engineering from their vantage point and that
they liked the relatively flexible and informal
organization of the course. They discovered that


TABLE 3
SUMMARY OF COURSE EVALUATION
No. of
responses
1972 1973


What aspects of the course did you
like the best?
1. Work on a realistic engineering
problem; opportunity to see the
work of an engineer.
2. Work in small groups; learning
how to work with others.
3. Informal class organization; flexible
scheduling of work; freedom to
work independently.
4. Challenging, relevant, different. 1
interesting design problem.

What aspects of the course did you
like the least?
1. Materials or information hard to
find, or interpret; design problem
too sophisticated.
2. Design problem too much work;
work not shared equally by
company members.
3. Course organization; location; 1
scheduling
4. Difficulty in getting started on
design problem.

What are your chief criticisms of the course?
Any suggestions for improving it?
1. Give a better idea of what is expected
early; provide more information
immediately.
2. Provide more reference materials
written at our level; give additional
lectures; better assistants.
3. Do shorter project, simpler project.
4. Arrange field trips.
5. Make scheduling more flexible; do not
require class meetings.

Has the course encouraged you to continue in
engineering or discouraged you from doing
so? Why?
1. Encouraged me.
2. Discouraged me.
3. Neither.


9 13


9 8

9 14


0 10




8 10


3 10


.0 6

3 5


22 30
4 1
4 8


engineering can be a lot of work and that infor-
mation gathering is a significant portion of that
work. Many suggested that I provide more infor-
mation through additional lectures and materials,
but this seems directly related to inexperience at
defining problems and organizing work effort.
Others suggested that the design problem was
too advanced for their background, but judging
from what they were able to achieve I do not feel
that this was the case. Significantly, only a small


WINTER 1975








fraction (5 of 69) indicated that the course had
discouraged them from continuing in engineering.
Some of these made comments like "Now that I
have seen what engineering may be like, I have
decided it is not for me."
On the whole, I feel that the course was highly
successful. The course was exciting and challeng-
ing to teach and I enjoyed it immensely. The
response of students was quite gratifying. It
seems clear that much of what I tried to build into
the course met with reasonable success. Whether
any long term benefits will accrue remains to be
seen. Certainly the students who took the course
have had very early in their course of study a
broad range of experience and exposure to en-
gineering that our typical student has never had
in the past. Several of the assistants commented
that they wished they had had such a course as
freshmen, indicating that it would have given
them much insight into their subsequent courses.
At the beginning of the semester, at least the
first time I taught it, the course consumed a great
deal of my time. This was due partly to my in-
experience with the course, but partly due to the
fact that all of the planning and course develop-


ment had to be done by the instructor. I found
no suitable text to use as a guide or to provide
problems. (The course just might be pretty sterile
if there were!) Moreover, the course needs to be
very flexible if it is to respond to the needs and
interests of the students. Towards the end of the
semester, especially as the design projects got well
under way, little time was required beyond that
spent in class. Teaching the course the second
time was much easier. I made some minor modi-
fications, but used essentially the same material
and format as the previous year. This, plus the
fact that I then knew how the students would
react, reduced my time commitment to a mini-
mum.
Provided assistants are available, I believe that the
course could be run in this fashion with as many as 50
students per section. For group projects, there should be
no more than 6 students per group. However, as the class
size increases one does risk destroying the informal and
personal atmosphere of the course. This could defeat the
purposes of the course. Also, larger class size probably
would mean a greater diversity of interests among the
students. This makes it more difficult to select projects
consistent with their interests. In any case, the instructor
should limit the spectrum of design problems going simul-
taneously in the course to avoid spreading himself too
thin in terms of his own interests and background. []


CACHE

COMPUTER

PROBLEMS


$50 PRIZE FOR EACH
PUBLISHED PROBLEM


CHEMICAL ENGINEERING EDUCATION, in cooperation with the CACHE (Computer Aides to Chemical
Engineering) Corporation, is initiating the publication of proven computer-based homework problems as
a regular feature of this journal.
Problems submitted for publication should be documented according to the published "Standards for
CACHE Computer Programs" (September 1971). That document is available now through the CACHE
representative in your department or from the CACHE Computer Problems Editor. Because of space
limitations, problems should normally be limited to twelve pages total; either typed double-spaced or
actual computer listings. A problem exceeding this limit will be considered. For such a problem the article
will have to be extracted from the complete problem description. The procedure to distribute the total
documentation may involve distribution at the cost of reproduction by the author.
Before a problem is accepted for publication it will pass through the following review steps:
1) Selection from among all the contributions of interesting problems by the CACHE Computer Problem
Advisory Board
2) Documentation review (with revisions if necessary) to guarantee adherence to the "Standards for
CACHE Computer Programs"
3) Program testing by running it on a minimum of three different computer systems.
Problems should be submitted to:
Dr. Gary Powers
Carnegie-Mellon University
Pittsburgh, Penn. 15213


CHEMICAL ENGINEERING EDUCATION










ChE Department: WATERLOO
(Continued from page 7.)

of the personality of the Waterloo department,
some accomplishments and hobbies of the faculty
are noted below:

T. L. Batke, Ph.D. (Toronto) is a past vice-president of
the University and was the first department chairman. He
has recently been cross-appointed to the Philosophy De-
partment where he teaches a graduate course. L. E.
Bodnar, Ph.D. (Master) is a past acting chairman, an
outstanding amateur photographer and an authority on
weaving. C. M. Burns, Ph.D. (Brooklyn Polytech. Inst.)
has a wide range of interest in polymers and as editor
for several years developed the CSChE Research Directory
into an important survey of research activity in Canada.
J. J. Byerly, Ph.D. (U.B.C.) is co-inventor of a patented
process to control water pollution by certain metallic com-
pounds. K. S. Chang, Ph.D. (Northwestern) is a consistent-
ly highly-rated teacher and is an accomplished amateur
magician, two attributes which prove valuable in his work
on control theory. F. A. Dullien, Ph.D. (U.B.C.) is an
active consultant to industry; his work on porous media
has found extensive applications. K. Enns, Ph.D. (Toronto)
is co-inventor with John Byerley of the water pollution
control process, and holder of a law degree. T. Z. Fahidy,
Ph.D. (Illinois) is an associate editor of Can. J. Chem.
Eng. also manages to come up with a minimum of one
joke per day. J. D. Ford, Ph. D. (Toronto) established our
Unit Operations lab. C. E. Gall, Ph. D. (Minnesota) man-
ages to bridge the two cultures of applied math and
theatre. He appeared in the Stratford Shakespearian
festival for a season and has worked in a T.V. drama
series (in a white lab coat!). A. H. Heatley, Ph.D.
(Toronto) is semi-retired, but is still active enough to
have purchased a small computer for his continuing work
on numerical methods of solving differential equations.
R. Y. M. Huang, Ph.D. (Toronto) works on polymers, has
served as President of the University Faculty Association,
and was the leading force in the University's annual
Hagey Lectures which brings to the campus such figures
as Fred Hoyle and George Wald for several days of dis-
cussion. R. R. Hudgins, Ph. D. (Princeton) is our current
associate chairman (undergraduate studies) and, when
not studying catalysis, plays the harpsicord, organ or
piano. I. F. Macdonald, Ph.D. (Wisconsin) has interests
that range from blood to polymers. M. Moo-Young, Ph.D.
(London) is the 1973 ERCO award winner for "distinguish-
ed contribution to ChE. in Canada," an associate editor of
"Advances in Biochemical Engineering," an active con-
sultant and, as a professional folksinger, has been record-
ed in live-concert on an album (Capitol-Dominion). G. S.
Mueller, Ph.D. (Manchester) is a University Residence
Tutor, coordinator of the Canadian Government-sponsored
aid-program to the University of Havana, and plays his
self-built organ. K. F. O'Driscoll, Ph. D. (Princeton) is
our present chairman, co-inventor of a patented process
for a soft-contact lens material; author of "Nature and
Chemistry of High Polymers" (Reinhold), co-editor of
Reviews in Macromolecular Chemistry, and has his own
company, (Polymeric Enzymes, Inc.). D. C. T. Pei, Ph.D.


(McGill) is a past associate chairman, and is currently
on sabbatical helping to establish a ChE curriculum in
Singapore. E. Rhodes, Ph.D. (Manchester) is our current
associate chairman (Graduate Studies), has developed a
successful format for our annual departmental visits by
high-school students, is co-editor of a two-phase flow
volume (Plenum). P. M. Reilly, Ph.D. (London) is winner
of a 1973 OCUFA "Outstanding Teacher" award. G. L.
Rempel, Ph.D. (U.B.C.) is very active in putting Chemistry
for all 800 first-year engineering students on a firm basis.
C. W. Robinson, Ph.D. (Berkeley is interested in PSI
teaching methods and has prepared a PSI manual for
mass transfer. J. M. Scharer, Ph.D. (Pennsylvania) has
interests in microbiology and nature in general. D. S.
Scott, Ph.D. (Illinois) is a past chairman, a past acting
Dean, the 1972 president of C.S.Ch.E., a Centennial Medal
winner, an active consultant, and co-editor of a two-phase
flow volume. D. R. Spink, Ph.D. (Iowa State) has been
a School Board member and still skates hard in the grad
students hockey games. P. L. Silveston, Ph.D. (Munich)
is an accomplished flyer and has his own consulting firm.
G. A. Turner, Ph.D. (Manchester) is author of "Heat and
Concentration Waves" (Academic Press). B. M. E. van
der Hoff, Ir. (Delft) is an associate editor of J. of Macro-
molecular Chemistry, who recently returned from a
sabbatical in Nigeria where he established research and
teaching in polymer Technology. J. R. Wynnyckyj, Ph.D.
(Toronto) is an active consultant, is interested in the role
of minority ethnic groups in Canada.


Location of University of Waterloo.


UNIVERSITY AND LOCATION

FOUNDED IN 1957, the University was the first of
several "new universities" in Canada. Today, it is
co-educational and multi-faculty with both conventional
and co-operative programs. The campus occupies 1,000
acres of landscaped grounds and is rated as one of Canada's
most beautiful.
The university is situated in the Regional Municipality
of Waterloo. Because Waterloo city is part of the larger
twin-city of Kitchener (overall population: 165,000) it is
often not shown on maps. Toronto is 60 miles to the
northeast, and Niagara Falls is 80 miles to the southeast.
The maps shows the spot! D


WINTER 1975










/1974 4wa'd iec&te


BIOTECHNOLOGY An Old Solution
To New Problems


ELMER L. GADEN, JR.
Columbia University,
New York, NY 10027


INTRODUCTION
M AN'S ESSENTIAL MATERIAL needs are
commonly said to be "food, clothing, and
shelter." In the parlance of an industrial civiliza-
tion a better statement might be (1) food, (2)
energy resources, and (3) material resources.
Food and energy resources can be considered to
be consumed immediately if we ignore processing,
transportation, and storage lags; material re-
sources, are those which are converted into
durable or semidurable goods.
The needs of pre-industrial man were satis-
fied in large measure by renewable resources.
Food supplies were completely renewable, al-
though somewhat uncertain. Although coal was
known to the Romans, its use was limited before
the 18th century; useful energy was obtained
mainly from water, wind, and wood. Non-renew-
able resources were exploited substantially only
in the fabrication of utensils, weapons, and struc-
tures, and even here recycling was significant.
Many a European farm house and villa in-
corporates carefully chiseled stones from Roman
walls and roads.
One consequence of the industrial revolution
was a rapid increase in dependence on non-renew-
able resources. Iron, and then steel, replaced
wood in structures, machinery, vehicles, and
ships; fossil fuels, coal, then oil and gas, became



One consequence of the industrial revolu-
tion was a rapid increase in dependence on
non-renewable resources. Iron, then steel
replaced wood in structures, machinery, vehicles
and ships; fossil fuels, coal, then oil and gas
became primary sources of energy.


-HYDROPOWE .------
0 __NUCLEAR
ENERGY



NATURAL GAS


PETROLEUM \-
NATURAL-GA
FUEL WOOD COAL LI UIDS

O -s



'1850 1875 1900 1925 15 1975 000
FIGURE I


the primary sources of energy. The rapidity of
this change is evident from the familiar data of
Figure 1 (1), indicating the energy sources em-
ployed in the United States since 1800.
Technological man has dramatically increased
this dependence on non-renewable resources.
Over the last thirty years the seeming abundance
of low-cost petroleum and natural gas give birth
to and sustained a burgeoning petrochemical in-
dustry. Through it a significant component of our
material as well as energy needs became de-
pendent on hydrocarbons. Synthetic polymers
have replaced cellulosic substances, wood, paper,
and cotton, in a host of applications while many
industrial chemicals, once prepared from renew-
able raw materials, are now synthesized from
petrochemical intermediates. Ethanol is the classic
example. In 1939 about 85% of the industrial
(non-beverage) alcohol produced in this country
was manufactured by the fermentation, most of
it from molasses and cereal grains. By 1960
ethylene had replaced these raw materials almost
completely.
Parallel with, and in part related to this shift


CHEMICAL ENGINEERING EDUCATION











At a point like this, one expects a clarion call for the development of new technology
but I believe that much can be accomplished with technology already at hand .
also that biotechnology-deliberate exploitation of the potential for chemical change
inherent in living cells-can contribute significantly to this effort.


in our resource base we have witnessed a signifi-
cant and accelerating deterioration of the physical
environment. The factors contributing to this
decay have been discussed many times but one
is directly related to the shift from wood to fossil
fuels. This is a massive, environmental carbon
imbalance. Carbon, fixed by photosynthesis and
subsequently converted to coal, oil, and gas over
millions of years, is being rapidly returned to the
atmosphere through the combustion of fossil
fuels. We do not know whether the consequences
of this imbalance will be as serious-even
dangerous- as some suggest but I would certain-
ly rest easier if carbon dioxide production were
better balanced by current photosynthetic activi-
ty (Figure 2).
We are now confronted with several vital and
interconnected problems arising from our great




CO2 + 120


-. Solar energy


CELLULOSE SUCROSE STARCH


> GLUCOSE---


ETHANOL


PROTEIN


FUEL ->-F
Thermal
energy

CO2 + H20


30D
Metabolic
energy


THE ECOLOGICAL CARBNN BALANCE
FIGURE 2


dependence on non-renewable resources:
* Petroleum and natural gas are in short supply and
expensive. Availability may be increased for a time but
the real cost will not decline. Furthermore, the en-
vironmental cost of substantially increased supplies
may be catastrophic, e.g. shale oil.
* Our agriculture has become intensive and productive
but at great cost, especially in terms of energy from
fossil fuels.
* The accumulation of wastes from this technological
structure has reached staggering proportions, especial-
ly in and around urban centers. Traditional methods
of disposal either consume large amounts of energy
or are environmentally unacceptable.

Most important, we now recognize that tech-
nological man has reached the point where his
needs for food, energy, and durable goods are
complex and interactive. The choices which can
be made in satisfying them are highly constrained
and often competitive. This is illustrated, albeit
in grossly simplified terms, by the schemes pre-
sented in Figures 3 and 4. They summarize the
various relationships, existant or potential, be-
tween the production of food proteins, energy for
transportation and power generation, and petro-
chemicals. In fact Figures 2 and 3 should be one
but such a presentation, even in the simple terms
employed here, would be excessively complicated.
I have therefore divided the total problem into
those elements which are pertinent to food protein
production (Figure 3) and those which provide
energy for power and transportation and feed-
stocks for petrochemical manufacture (Figure 4).
The significant points to be noted with respect
to Figure 3 are:
Cereal grains comprise the primary protein source for
most of the world's population. Increased productivity
can be achieved but only at the cost of relatively greater
expenditures of fossil fuels, Heichel [2] has pointed out
that modern agriculture derives practically all of its
"cultural" (other than solar) energy from fossil fuels
or other sources which replace labor. Increases of 10-
to 50-fold in the cultural energy employed have only
doubled or tripled the yield of digestible food energy.
Major sources of protein for animal feeding are cereal
grains, soy bean and fish meal. In addition, molasses,
supplemented with nitrogen and phosphorus, has be-
come a popular component of livestock feeds during the


WINTER 1975


I









* N AT' ~-.-'Wi'I I


- ET g'C::


- LSH 1


FIGURE 3. Food Relationships

past two decades. In 1946 less than one-third of
molasses consumed in the United States was used
livestock feeding. U. S. molasses consumption todd
more than double that in 1946 and over 80% of
used for liquid animal feeds. This escalation in den
coupled with shortages of soybean and fish meal,
resulted in a three-fold increase in molasses prices
the last two years.
* Microbial protein is another potential contribute
both animal and human diets. Virtually all of the m
bial protein produced so far has been derived
molasses, primarily cane and beet. It is also techni
possible to produce microbial protein from met
(very low yields) or methanol,. from paraffins, and
ethanol. Commercial production from both alcohols
in fact, been announced [3, 4].
* Molasses was the dominant raw material for eth
production prior to 1940. As we have seen, ferm
tion alcohol has subsequently been replaced al
completely by the ethylene-based product.
* Waste or virgin cellulose offers another potential
material for the production of either microbial
tein or ethanol.

With respect to Figure 4 it should be noted thf

* Electric power generation in the United States is
rently dependent upon coal, natural gas, petroleum,
hydropower almost exclusively. Methanol is a pote
fuel, either directly or following reconversion to
thane.
* Methane may also be produced by the anaerobic di
tion of cellulose and other solid wastes. Prolysi
such materials can also give oil and gas fractions
to be suitable as burner fuels.
* Transportation is almost totally dependent
petroleum. Here we face a growing conflict beti
petrochemical needs and increased demands for
matic components in gasoline to compensate for
reduction in performance occasioned by the elimina
of lead.
* Ethanol is another potential fuel for internal com
tion engines. As we have seen, it can be produced f
a wide variety of saccharides including the glu
generated by cellulose hydrolysis,


cur-
and
ntial
me-

iges-
s of
said

upon
veen
aro-
the
Ltion

bus-
rom
cose


METHANE
anaero.bic digestion
CELLULOSE p. Tolys s

STALUCORCHSE

STARCH


--METKENOL
POWER
GENERTOF
OIL/GAS

I _-


ETHYLENE ---ETHANOL- -
PETROLEUM -- TRANSPORTATION
-,-GAS ILS -- -- DIESEL FUEL
00RE0U0ED CRUDE----FUEL OIL

SFIGUntr e rw mEneriagy Relationships

FIGURE 4. Energy Relationships


CHEMICAL ENGINEERING EDUCATION


.. No matter what time scale one accepts for the
continued availability of our fossil fuel resources,
it is apparent that we must redress the imbalance
of recent decades and move toward a greater de-
pendence on renewable resources. This must be
done in a manner which maximizes benefits by
coupling material and energy generated in one
sector as closely and efficiently as possible with
material and energy needs elsewhere. Szego and
Kemp [5] and Klass [6] have recently presented
T. EI. provocative analyses of the technical and
economic aspects of renewable fuel resources.
These proposals are based on direct combustion
of wood (Szego and Kemp) and anaerobic diges-
tion to methane (Klass).
the There is no question that such a trend will
I for have immense social impact. It will therefore be
ay is necessary to achieve a finer degree of integrated
it is technical, economic, and social projection and
and,
has planning than we have ever achieved before.
over At a point like this one expects a clarion call
for the development of new technology but I be-
*r to lieve that much can be accomplished with tech-
icro- nology already at hand. I also believe that bio-
from technology-deliberate exploitation of the poten-
cally tial for chemical change inherent in living cells-
hane
from can contribute significantly to this effort. I pro-
has pose to support these contentions by examining a
specific proposal-the production of ethanol for
hanol use as an internal combustion engine fuel. I am
enta- not going to argue for this proposal-although it
most would be false for me not to confess an attraction

raw for the prospect. Rather I want to use it to il-
pro- lustrate the opportunities which have been creat-
ed by the sudden and, I believe permanent, rise in
at: the real, relative cost of petroleum.
Before we look at this specific case, however,


FIS --









a few points about biotechnology and its potential
role in the utilization of renewable resources are
in order.

BIOTECHNOLOGY
I HAVE ALREADY ALLUDED to the special
role which I expect biotechnology to play in in-
creasing our dependence on renewable resources.
Now I want to briefly outline the basis for that
belief. Biotechnology can best be defined as the
exploitation, under reasonably controlled condi-
tions, of the potential for chemical change in-
herent in biological systems. Important applica-
tions include (1) isolation, purification, and modi-
fication of biologically active materials, (2) the
use of individual enzymes and complete enzyme
systems to effect chemical transformations, and
(3) the use of populations of whole cells for the
same purpose (fermentation, biological waste
treatment, etc.).
As tools for generating chemical change,
biological systems are powerful but often circum-
scribed [7]. They can catalyze a wide variety of
chemical reactions, organic and inorganic, includ-
ing oxidation, reduction, hydrolysis, substitutions,
group transfers, etc. [8]. Products can be ob-
tained through both endergonic (AG=- +) and
exergonic (AG -) reactions, thanks to the
unique energy transfer and coupling mechanisms
found in living cells.
A considerable spectrum of raw materials is
available for biological processes. In the realm of
organic reactions these are referred to as "carbon
sources." The traditional-and still the most wide-
ly used-carbon sources in biotechnology are the
carbohydrates, especially starch and sugars. Re-
actions involving the exergonic degradation of
sugars to products, alcohol production from glu-
cose for example, are common. In other cases the
energy obtained from sugar oxidation is coupled
to energy-demanding processes (endergonic) to
permit biosynthesis of complex structures, cell
protein for example.
Recently hydrocarbons have become the focus
of considerable interest as potential carbon
sources for biotechnology. They supply much
more energy per unit mass and yields of cell pro-
tein are correspondingly higher. On the other
hand they introduce many problems for which
satisfactory solutions are available, but expensive.
In addition, recent rises in the costs of hydro-
carbon raw materials have cast a pall over this
whole matter.


Cellulose is another carbon source of potential
value. Biological degradation of cellulose is an
obvious and dominant feature of the natural
world. But it is also a painfully slow process in
nature. Generations of biologists have sought
organisms and conditions which will achieve more
rapid degradation of cellulose but success has not
come easily. The great advantage of the carbo-
hydrates-starch, cellulose, and the lower saccha-
rides derived from them-is, of course, their po-
tential renewability. Cultivation of carbohydrate
producing plants represents the conversion-ad-
mittedly at low efficiency-of solar energy to
available chemical energy.


biotechnology is relatively simple.
Inherent in the use of biological systems
is the employment of only moderate
temperatures and pressures. Equipment is
therefore relatively inexpensive and
process plants are not so
capital-intensive.


Another aspect of biotechnology which has
been overlooked is that it is relatively simple. In-
herent in the use of biological systems is the em-
ployment of only moderate temperatures and
pressures. Equipment is therefore relatively in-
expensive and process plants are not so capital-
intensive as are those employed in the petro-
chemical area. Another point which follows from
these observations is that plants employing bio-
logical processes are less sensitive to scale-factors.
It is therefore possible to build several smaller
units at a cost not much greater than one large
unit.

CHEMURGY AND BIOTECHNOLOGY

T HE CONTINUED AGRICULTURAL sur-
pluses of the 1920's and 30's led to the de-
velopment of the "chemurgic" movement [9].
Chemurgy included a number of specific pro-
posals whose general objectives were to channel
farm surpluses into the chemical industry for con-
version to non-food products. Specific aims of the
movement were:
to discover new uses for established farm crops
to develop new crops for acreage producing surpluses
of established crops
to make use of agricultural residues and wastes from
industries consuming agricultural materials


WINTER 1975









Biotechnology was a key element in the overall
chemurgic concept because biological processes
offered some of the most promising avenues for
utilizing agricultural materials. One of these was
the proposal to hydrolyze starch from cereal
grains to glucose and then ferment the glucose
to ethanol for use as a motor fuel. We will look
at this more closely in the next section.
The great hopes of the chemurgic movement
came to naught because:
* increased needs for food crops during and after World
War II largely eliminated low-cost surpluses and led
to a steady rise in the prices of commodity grains.
* rapid development of the petrochemical industry, based
on low-cost hydrocarbon feedstocks, offered direct com-
petition in many of the areas which seemed most at-
tractive for chemurgic development. The example of
ethyl alcohol, cited earlier, is typical.
Recently the chemurgic concept has been trotted
out, dusted off, and presented anew [10]. Its pitch
has been changed, however. The raw materials of
interests are no longer the cereal grains but
rather the wastes and by-products generated by
an industrialized agriculture and the society
which it feeds.

FUELS FROM CELLULOSE

CELLULOSE, AS WOOD, is man's oldest fuel.
It was not replaced by coal until the 19th


century (Figure 1) and it is still the primary fuel
for large segments of the world's population. The
various natural woods exhibit somewhat higher
heats of combustion that pure cellulose because of
the oils and other materials which they contain
but the differences are not significant. Wood is,
of course, unsatisfactory for metallurgical ope-
rations because combustion temperatures are too
low. It was therefore necessary, before coal be-
came available, to convert wood to charcoal.
The great advantage offered by cellulose as a
fuel is its renewability. This is the key to the pro-
posal by Szego and Kemp [5] for "energy planta-
tions." Substantial use of cellulose as a fuel would
permit a more favorable environmental carbon
balance, as we have seen (Figure 2). Carbon
dioxide returned to the atmosphere would be
equivalent to that removed. On the other hand
cellulose cannot be used as a fuel for one of tech-
nological man's most prized possessions, the in-
ternal combustion engine. If renewable fuel re-
sources are to be seriously considered, effective
means must be found to convert them to useful
liquid or gaseous forms.
The various proposals which have been made
for the employment of cellulose as a fuel fall into
four main categories (Table 1). These are:

* direct combustion
* pyrolysis to combustible oil and gas fractions


TABLE 1


Comparison Of Cellulose-Based Fuels


Direct combustion
of cellulose

Pyrolysis to oil
and gas fractions

Anerobic digestion
to methane


Conversion to
ethanol
(Gasoline)


Heat of
combustion
3.5 kcal/gm


12.4 kcal/gm


7.1 kcal/gm


Energy
efficiency (a)
100%


35% (11)


65% (11)


50%


11.2- 11.3
kcal/gm


Notes
(a) Energy efficiency refers to the fraction of the energy available in
final fuel.
(b) Other than CO and CO,


Limitations
External combustion
only: conventional
burners.
External combustion only:
conventional burners.

External combustion-
conventional/Internal
combustion-high-
pressure storage.
Internal combustion:
conventional design.


Pollution (b
Particulate


9


None


None


Hydrocarbons,
SO,

the original cellulose which is available in the


CHEMICAL ENGINEERING EDUCATION










I am convinced that most current assessments of the future potential for various fuels
is unrealistic because they are based upon established ratios between energy
and other costs Ethanol is the only reasonable candidate fuel for internal
combustion engines which can be derived from renewable resources.


* anaerobic digestion to methane
* conversion to ethanol

Direct combustion of cellulose, usually in mix-
tures with other wastes, is already widespread.
The use of wood wastes and shredded garbage in
steam generating units are the most common
examples. Pyrolysis schemes are still largely in
the development stage but methane from the di-
gestion of sludge and similar organic wastes has
long been used as a fuel in waste treatment plants
and sometimes in the surrounding community.
The fourth possibility, hydrolysis of cellulose
to ethanol, is the only one which offers a liquid
compatible with contemporary internal combus-
tion engines. Alcohols, methanol and ethanol al-
most exclusively, enjoy a long history of use as
internal combustion engine fuels. They were used
experimentally in the early development of these
engines when petroleum-based fuels were less
readily available and have been widely employed
when petroleum was in critical supply (Germany
during the first World War; Eastern Europe after
it).

ETHANOL AS A MOTOR FUEL

T HERE IS ABUNDANT experience with
ethanol as a motor fuel. It offers several ad-
vantages over, and suffers from some disadvant-
ages in comparison with, gasoline. The most ob-
vious disadvantage is its lower energy content
(heating value) per unit weight (Table 1). This
means that a larger volume and weight of fuel
must be carried for the same vehicle range. Fuel
lines, pump, etc., will also have to be larger to
deliver the same fuel energy to the engine. Etha-
nol also exhibits a higher heat of vaporization
which means that more heat must be supplied to
the intake manifold of a carburetted engine. This
is usually waste heat from the engine, however,
and therefore represents no thermal penalty to
the engine.
On the other hand, ethanol has a high octane rating
(RON = 106). It should therefore be possible to design
an Otto cycle engine for alcohol with a higher compression
ratio, and hence higher thermal efficiency, than can be


realized with gasoline. With the removal of lead, it has
already become necessary to increase the aromatic content
of gasoline in order to maintain current octane ratings.
This has placed an additional demand on already pre-
carious supplies of petrochemical feedstocks. Indeed, the
question is widely asked whether we can afford to burn
such precious commodities. Alcohol also offers substantial
advantages over gasoline with respect to air pollution
control. It contains no sulfur, leads to no unburned hydro-
carbon, and the lower engine temperatures involved reduce
NO. formation.
So far, alcohol has been used almost exclusive-
ly in engines which were designed for gasoline.
The development of smaller, higher compression
engines for light-duty personal vehicles, com-
muter buses, smaller carriers, etc., is an especially
attractive concept. Such an engine could exploit
the unique advantages of ethanol as a fuel and
could find immediate application in captive
market services-urban transit, delivery fleets,
etc.


POWER ALCOHOL
SpOWER ALCOHOL" HAS had a checkered
record in ordinary times [12, 13]. During
the 20's and 30's many European countries either
made the supplementation of gasoline with al-
cohol (10-15% was typical) mandatory or pro-
vided tax incentives to encourage it. These pro-
grams reflected both the general agricultural de-
pression affecting much of the world during this
period and the availability of surplus alcohols-
from excess wine production, for example-in
some countries.
Although these alcohol-supplemented fuels
were satisfactory in a technical sense, the overall
programs were less so. It has been claimed [14]
that the essential difficulty was the instability of
alcohol supplies. Since surpluses were the basis,
the supply of alcohol for incorporation in fuel
varied greatly and government regulations were
changed frequently. This necessitated equally fre-
quent engine adjustments followed by increasing-
ly negative consumer reaction.
Willkie and Kolachov [14], in a provocative
argument for an extensive, carefully planned


WINTER 1975








alcohol program, urged the use of pure (190-proof
or 90%) alcohol, rather than blends. They argued
that "captive" markets existed, farm tractors
for example, which could support such a program
and that the use of pure alcohol rather than
blends would eliminate the greatest short-coming
of the earlier program. Willkie and Kolachov's
proposal was published on the very eve of
America's entry into the second World War. It
represented the culmination of one of the


We must recognize the vital importance
of developing renewable resource bases for our
energy needs.


strongest arguments in the "chemurgy" program
of the 1930's, conversion of grain surpluses to
power alcohol. The exigencies of a war economy,
however, overwhelmed it. Grain surpluses disap-
peared as we were called upon to feed our allies
during the war and much of western Europe after
it. There was considerable production of alcohol
from grain during the war but this was needed
to supply increased industrial requirements and
to replace the imported molasses previously used.
Since 1945 the United States has helped to
supply the food needs of nations which had pre-
viously been cereal grain exporters but whose
population growth had outstripped their own
productive resources. The grain surpluses of
earlier decades steadily dwindled away until, in
the 1970's, we encountered shortages, for export
at least, and rapidly increasing prices. Even in
this unfavorable climate, the possibility of pro-
ducing alcohol from starch for motor fuel use has
been resurrected [15, 16]. In 1971 the Nebraska
Legislature took the first positive step with pas-
sage of a law [17] providing for an allowance
of 3-cents per gallon on the state motor fuel tax
when fermentation ethanol is added to lead-free
motor fuels. As the specter of fuel shortages be-
came more real, pressure for the use of gasoholl,"
a 90% gasoline-10% alcohol blend increased.
One Nebraska legislator suggested last year [17]
that should gasoline prices rise to 65-70 cents per
gallon, alcohol would become competitive.
At the same time that these predictions were being
offered, however, the violent shifts in the world's grain
markets experienced over the last year were just coming
into play. These dim the prospects for grain-based ethanol
for motor fuel just as petroleum price increases favor it.
Once again we see at work the increasingly close inter-


actions between food and energy production previously
outlined in Figures 3 and 4.

ALCOHOL FROM CELLULOSE
T HE HYDROLYSIS OF cellulose to glucose by
various agents has held the interest of gene-
rations of applied scientists. Acid saccharifica-
tion processes were described early in the 19th
century and were successfully employed in
Europe, especially Germany [18]. Much of the
glucose produced was then fermented to ethanol.
Alcohol has also been produced commercially from
the sugars in waste sulfite liquors and other
similar materials [18]. Acid hydrolysis of cellu-
lose is an expensive, relatively low-yield process,
however, and the advantages of enzymatic pro-
cesses were recognized early. Unfortunately, satis-
factory cellulase preparations were not available.
More recently, however, the technology of cellu-
lase preparation and its application has developed
rapidly [19, 20]. Yields of glucose from waste
cellulose of 50% and greater have been reported
[21]. Cost estimates for the enzymatic production
of glucose from cellulose vary widely, however,
because of still unresolved questions about the
amount of pretreatment necessary. Using a range
of glucose costs covering most of the predictions
made so far, plus past experience with ethanol
fermentation costs, it is possible to estimate costs
for ethanol production from cellulose (Table 2).
These estimates include a rough credit for the
protein-rich "distillers solubles" which are pro-
duced as a by-product but they do not include any
credit for the elimination of solid wastes, mixed
municipal refuse (MMR) for example, which
may be applicable.
One should properly ask, "How much alcohol
could be produced in this way and what impact,
if any, would this have on the nation's fuel
needs?" At this point the only answer to this
question must be a crude estimate. We are said to
produce about 200-million tons of MMR per year
in the United States and these solid wastes are
about half cellulose. Assuming demonstrated
yields for glucose from waste cellulose and ethanol
from glucose, these wastes could yield 25-million
tons of ethanol, or about 8-billion gallons (190-
proof), per year. This is equivalent to 0.58 x 15'"
BTU/year. Current U.S. gasoline consumption is
about 100-billion gallons or 11.5 x 10"5 BTU per
year. Conversion of all our MMR to ethanol would
therefore provide only 5% of the energy now con-
sumed in gasoline engines. Even so, this fraction


CHEMICAL ENGINEERING EDUCATION










TABLE 2 Cost of Ethanol From Cellulose


Raw material
$1.38


0.69


0.14


Conversion
$0.15 0.30(1)
(0.10 0.15) (2)
0.15 0.30
(0.10 0.15)
0.15 0.30
(0.10 0.15)


(1) Higher estimate based on past experience in production of ethanol from waste sulfite liquor; lower estimate by
author.
(2) Figures in parentheses reflect higher credits for conversion by-products utilized in animal feeds.


is not significant, especially if the use of fuel al-
cohol were concentrated in captive services for
urban areas. These services--street level trans-
portation, delivery vans, refuse trucks, etc.-are
major contributors to urban air pollution and the
employment of ethanol as a fuel would be par-
ticularly advantageous in reducing emissions.

SUMMARY AND CONCLUSIONS

A NUMBER OF ARGUMENTS have been put
forward in this discussion and I will con-
clude by summarizing what I believe to be the
most important of these:

* We must recognize the vital importance of developing
renewable resource bases for our energy needs.
* Ethanol is the only reasonable candidate fuel for in-
ternal combustion engines which may be derived from
renewable resources. While it is unlikely that ethanol
can supply a substantial portion of the total national
requirement for such fuels, it could contribute sig-
nificantly to captive market needs in urban areas.
* Finally, I am convinced that most current assessments
of the future potential for various fuels are unrealistic
because they are based on established ratios between
energy and other costs. The problem is not simply a
matter of providing inflationary allowances in cost pro-
jections. It is a question of the essential relationship
between the future cost of energy from conventional
sources and the other costs involved in fuel production.
Energy intensive technologies, e.g. shale oil, coal con-
version, etc., will suffer increasing penalties as the
relative cost of energy rises and projections based on
past energy cost experience are bound to be in
error. []

REFERENCES

1. Cook, E., "The flow of energy in an industrialized
society," Scientific American, September 1971.
2. Heichel, G. H., Comparative Efficiency of Energy
Use in Crop Production, Bull. 739, Connecticut State
Agricultural Experiment Station, New Haven (No-
vember, 1973).


3. Rozenzweig, M., and Ushio, S., "Protein from
methanol," Chem. Engr., January 7, 1974, p. 62.
4. Chem. Engr. News., April 22, 1974, p. 29.
5. Szego, G. C., and Kemp, C. C., "Energy forests and
fuel plantations," Chemtech, 275 (May, 1973).
6. Klass, D. L., "A perpetual methane economy-is it
possible?," Chemtech, 161 (March, 1974).
7. Rainbow, C., and Rose, A. H., Biochemistry of In-
dustrial Microorganisms, Academic Press, London
(1963).
8. Stodola, F. H., Chemical Transformations by Micro-
organisms, Wiley, N. Y. (1958).
9. Herrick, H. T., "New and better uses for our crops,"
in Crops in Peace and War; the Yearbook of Agri-
culture, 1950-1951, p. 6-9, U. S. Government Printing
Office, Washington (1951).
10. Davis, J. C., "Chemurgy's second coming," Chem.
Engr., p. 90, April 29, 1974.
11. Klass, D. L., and Ghosh, S., "Fuel gas from organic
wastes," Chemtech, 689 (November, 1973).
12. Jacobs, P. B., and Newton, H. P., Motor Fuels from
Farm Products, USDA Misc. Pub. No. 327, Washing-
ton, D. C. (December, 1938).
13. Hilbert, G. E., Alcohol from Agricultural Sources as a
Potential Motor Fuel, USDA Publication AIC-233
(Rev.), Washington, D. C. (February, 1950).
14. Willkie, H. F., and Kolachov, P. J., Food for Thought,
Indiana Farm Bureau, Indianapolis, Ind. (1942).
15. Miller, D. L., "Industrial alcohol from wheat, Sixth
National Wheat Utilization Conference, Oakland,
California, November 5-7, 1969.
16. Miller, D. L., "Fuel alcohol from wheat," Seventh
National Wheat Utilization Conference, Manhattan,
Kansas, November 3-5, 1971.
17. Chemical Week, p. 24, April 4, 1973.
18. Prescott, S. C., and Dunn, C. G., Industrial Micro-
biology, 3rd Ed., McGraw-Hill, N. Y. (1959).
19. Hajny, G. J., and Reese, E. T., Cellulases and their
Applications, Advances in Chemistry Series, No. 95,
American Chemical Society, Washington, D. C.
(1969).
20. Ghose, T. K., and Kostick, J. A., Biotech. Bioengr.,
12, 921 (1970).
21. Brandt, D., Hontz, L., and Mandels, M., AIChE Sym-
posium Series No. 69, 127 (1973).


WINTER 1975


Glucose cost
$0.10/lb


0.05/lb


0.01/lb


Total
$1.53 1.68
(1.48 1.53)
0.84 0.99
(0.79 0.84)
0.29 0.44
(0.24 0.29)









BOOK REVIEW: Schultz
(Continued from page 31.)
There is one chapter devoted to polymerization,
but it would not satisfy most people who include
such material in an introductory course.
There is a uniqueness in the first four chapters,
however, that will appeal to materials science
specialists, especially those who are interested in
interdisciplinary approaches to materials science.
After an introductory description of the shape,
configurations and conformations of polymer
molecules, Professor Schultz embarks on a clear
and carefully written exposition on polymer
crystal structure. He introduces the reader to the
morphology of single crystals through the tech-
niques of microscopy. He discusses the principles
of electron microscopy and electron diffraction
and then interprets pictures of polymer crystals
in a very readable manner. He repeats the process
using data from optical microscopes, dark field
methods and polarized light techniques. This
seems to be a particularly appealing way to intro-
duce the subject matter. The physical structure
of polymer crystals is complex indeed, and the
interpretation of microscope pictures is usually
a very frustrating experience for those who are
inexperienced in the subtleties of microscopy.
Professor Schultz tries to interpret through
words and supplementary sketches what is not
evident to the untrained eye. The study of poly-
meric crystals through small angle X-ray
scattering and study of the details of molecular
arrangement through NMR and infra-red tech-
niques are also covered in the second chapter. He
includes a few exercises for the students and
presents an extensive bibliography that will be
very useful to a researcher in the field. The third
chapter starts with a qualitative description of
crystals formed from the melt, with a clear ex-
planation of why they are different from those
formed from a dilute solution. This is followed by
a description of spherulite morphology on morph-
ology. An up-to-date bibliography is again in-
cluded. The fourth chapter is devoted to a de-
finition of degree of crystallinity in terms of the
variety of experimental techniques used for its
measurement.
It is not until Chapter 9 that Professor
Schultz completes his exposition on crystallinity
by including a very good chapter on crystallization
kinetics and mechanisms.
Chapters 1 to 4 and 9 constitute one of the


better introductory discussions of polymer crystal
structure. I wish these 265 or so pages had con-
stituted a smaller, less expensive book that could
have been purchased as a supplement to a more
general text in polymer engineering. The material
in the remaining six chapters is presented clear-
ly and the quality is commensurate with the other
introductory textbooks in the field, but the sub-
jects are only loosely connected, show less depth
and are considerably less original in the mode of
presentation. The trouble is that everyone has
his own ideas about how to present the remaining
material in a classroom situation and there is not
enough material in these chapters to supplement
in-depth lectures. Whereas the material on
crystallization is so well done that most instruc-
tors will defer to Professor Schultz's approach,
the remaining material is too sketchy for self
study and too weak to compete with each person's
own ideas. In Chapter 7, for example, the average
student will become lost in a maze of equations
describing rubber elasticity, without developing
much appreciation of the properties of rubber.
He would be better advised to read a standard
treatise on rubber elasticity for the kind of in-
formation that is presented here in abstracted
form. After the section on rubber elasticity, con-
tinuum mechanics is introduced in order to explain
the effects of fillers. This is just too much material
for the average student to handle alone. The
average instructor with a serious interest in this
material will not introduce it in such a superficial
manner, while the instructor with a more qualita-
tive interest will not wish to introduce so many
abstract quantities. The degree of superficiality
leads to misinterpretation in several places. For
example, the presentation of data on the effect
of fillers on glassy polymers (Figure 7.16) and
the development of the Kerner equation are inter-
laced with discussions of the effects of fillers on
elastomers without clarifying the important
differences between rubbery and glassy matrices.
Similar comments can be made about the short
sections on viscosity and fracture, the brief
chapter on time-dependent properties and the
surveys of Chapters 10 and 11.
All things considered, I found this to be a very good
text for an introductory course that emphasizes correla-
tions between structure and properties. Also, if one is
planning to do research in the area of polymer crystal
structure, this book gives an excellent introduction to
the field. I certainly would buy a copy for my own book-
shelf and I have no hesitation in recommending it to my
students and colleagues. ]


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z 0 < u => 0 w C) z ex w w z C) z w ex 0 LI. w u 0 V) z j w u. 0 z 0 V) > 0 C) z ex w w z C) z w _, <( u w :i::: u VOLUME IX NUMBER l WINTER 197 5 SPECIAL LABORATORY ISSUE A New Look . . DOUGLAS Design with Senior Lab . OVERHOLSER WOLTZ, GODBO L D Non-Newtonian Fluids WALAWENDER & CHEN SelfPaced Lab . . . RASE Precision of Data HALL, KIRWAN UPDIKE First Year Experiments . . GERRARD Also A Freshman Design Course University of Washington's BRUCE FINLAYSON CHE AT WATERLOO 1974 ./I~ .feci@,e GADEN: Biotechnology YOUNGQUI S T An Old Solution for New Problems

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WE ENCOURAGE JOB HOPPING. In fact at Sun Oil we ve just adopted a new system that promotes it. Internal Placement System. Here s how it works Say you re in Production and you decide to take a crack at Marketing. Next opening in Marketing we 'll tell you You can apply and be considered. First. You have freedom to experiment and move around at Sun You learn more and you learn faster. :& .. .. ~ .. Why do we encourage job hopping? Because we happen to believe our most valuable corporate assets are our people The more our people know the stronger we are. Now-you want to know more? Ask your Placement Director when ,;, a Sun Oil recruiter will be on campus Or write ~for a copy of our Career Guide. SUN OIL COMPANY Human Resources Dept. CED. 1608 Walnut Street Philadelphia Pa. 19103. An Equal Oppo r t u n it y E mployer M F

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EDITORIAL AND BUSINESS ADDRESS Department of Chemical Engineering University of Florida Gainesville, Florida 32611 Editor: Ray Fahien Associate Editor: Mack Tyner Business Manager: R. B. Bennett (904) 392-0881 Editorial and Business Assistant : Bonnie Neelands (904) 392-0861 Publications Board and Regional Advertising Representatives: SOUTH: Charles Littlejohn Chairman of Publications Board Clemson University Hom er F. Johnson University of T e nnessee Vincent W. Uhl University of Virginia CENTRAL: L eslie E. Lahti University of Toledo Camden A. Coberly University of Wisconsin WEST: William H. Corcoran California Institute of Technology G e orge F. Meenaghan Texas Tech University SOUTHWEST: J. R. Crump University of Houston Jam es R. Couper University of Arkansas EAST:G. Michael Howard University of Connecticut L e on Lapidus Princeton University Thomas W. Weber State University of New York NORTH: J. J. Martin University of Michigan 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, Santa Barbara FALL -1974 Chemical Engineering Education VOLUME IX NUMBER l WINTER 1975 FEATURES 40 ./IUJalUi ./!edw,,e 197 J/. Biotechnology-An Old Solution to New Problems, E. Gaden DEPARTMENTS 2 The Educator Bruce Finlayson of U. of Washington 4 Departments of Chemical Engineering University of Waterloo 32 Classroom An Int roductory Design Course for Engineering Freshmen G. Younquist 8 Views and Opinions Some Comments on ChE Laboratory Courses, J. M. Douglas 31 Book Review 31 News Laboratory 10 Flow Curve Determination for Non Newtonian Fluids, W. Walawender and T. Chen 16 Teaching Process Synthesis, K. O v erholser, C. Wolt z and T. Godbold 22 Preliminary Appraisal of a Self Paced Laboratory, H. Rase 24 Re-porting Precision of Experiments K. Hall, D. Kirwan and 0. Updike 28 Some Simple Experiments for First Year Students A. Gerrard 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 Ga i nesville, F lorida 326 11. Advertising rates and information are available from the advertising representatives. Plates and other advertising material may be sent directly to the printer: E. O. 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 1975. Chemical Engineering Divi s ion of American Society for Engineering Education, Ray Fabien, Editor. The statements and opinions expresse d in this periodical are those of the writers and not necessarily those of the ChE Division of the ASEE which body assumes no responsiMlity for them. Defective copi es replaced if notified within 120 days. The International Or ga niz atio n for Standarization has assigned the code US ISSN 0009-2479 for the identification of this periodical. 1

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[! ;j a educator BIUtc,e tl);,ntu,~on OF UNIVERSITY OF WASHINGTON Bruce has developed an enviable reputation as a teacher C. A. SLEICHER Uni ve rsit y of Washington Seattle, W ctsh in gton 98195 N OW IT CAN BE REVEALED. There really is an Okie-from-Muskogee in our midst! Bruce Finlayson-musician, hiker, sailor, skier, plumber, carpenter, committee chairman, hus band, father, chemical engineer, talented research er dedicated teacher grew up in Muskogee, w;nt to high school in Muskogee, played in the Muskogee High School band. Indeed, his interest in the band (He was a drummer), was to alter the course of his life. From high school he went to Rice University, joined the band, and there met a lovely lyre player, Pat Hill s. That in turn led to Mark, aged 10; Catherine, aged 8; Chris, aged 6; and numerous other manifestations, great and small. Bruce worked his way through Rice by seholarships, by playing in a dance band, and by ~~ iting on the training table. He also worked summers, and on employment applications de scribed his occupation as "unemployed waiter." The re lation b et ween this description and the 2 summer jobs he took is obscure; he sold pots and pans, was a gas station attendant, and taught goat lassoing on a dude ranch. Now, it is comfort ing to think that this last experience stimulated his interest in the noble profession of teaching, but to tell the truth it was quite irrelevant. In reality his interest in teaching developed by acci dent. We return to the band and Pat. A FATEFUL YEAR A T RICE, BRUCE WAS in the N.R.O.T.C., which forbade getting married before getting a commission at the end of a five-year program. That proved too long for Bruce and Pat, so he was commissioned after four years, took an im mediate leave of absence from the Navy, got married, and stayed at Rice to complete a Master's degree program in his fifth year. That year proved to be a fateful one; while working on his thesis on nucleate boiling, he became interested in teach ing and research and decided once again to post pone his Navy duty and continue graduate study i.nstead The next y ear he enrolled in the graduate program at the University of Minnesota where he worked on a Ph.D. program under Professor L E. (Skip) Scriven, a demanding but stimulating ex perience. His studies of the essential differences between true variational principles and quasi and ad ho c ones were published in a series of papers with Skip Scriven. This led to a unity of viewing approximation methods for solving differential The bulk of his research is in applied math but he is committed to studies that have application, and many of his students do e x perimental work . His studies of variational and appro x imate methods were collected in a book which appeared in 1972 amid numerous favorable reviews. CH EMI CAL ENGINEERING EDUCATION

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Bruce bicycles to work -rain or shine. equations of fluid mechanics and heat and mass transfer which Bruce then applied to an investiga tion of the motion of certain fluids having a non symmetric stress tensor. After completing his graduate studies at Minnesota, he embarked on a two-year period of duty with the Navy ii). Wash ington, D. C. In 1967 Bruce and his growing family moved to Seattle, where Bruce joined the Chemical En gineering Department at the University of Wash ington. In the seven short years he has been here, he has developed a research program that has achieved national and international repute The bulk of his research is in applied mathematics, but he is committed to studies that have applica tion, and in consequence many of his students do experimental work. His current experimental work is on the effects of magnetic fields on liquid crystals and on flow properties in radial fiow re actors In the applied mathematics area he began to apply approximate methods to model chemical reactors, axial dispersion in packed beds, and catalytic mufflers. This work made use of the method of orthogonal collocation, some of it applied to three-dimensional, transient situations, and recently he was asked to write a review paper on orthogonal collocation in chemical reaction engineering (Cat R ev S ci .-E n g. 10 69-138, 1974). Bruce's studies of variational and approximate methods were collected (and extended) in a book, "The Method of Weighted Residuals and Varia tional Principles," w hich appeared in 1972 amid numerous favorable reviews One result of the publication of the book was an invitation to be an invited speaker at the International Sym posium of Finite Element Methods in Flow Prob lems, held at University of Swansea, Wales in WINTER 1975 January 1974. Some of his current research centers on extending some of the ideas in the book to more than one dimension. Bruce believes that the method of orthogonal collocation on finite ele ments may greatly reduce the machine computa tion time required for twoand three-dimensional, non-linear problems, and he has begun to test out these ideas in the field of petroleum reservoir c alculations. TEACHING REPUTATION T HOUGH WIDELY RECOGNIZED for his research, Bruce has developed an enviable reputation as a teacher. He enjoys teaching and acquires a sense of excitement as each quarter approaches and new classes begin. He keeps his office door open; there is no buff er between him and students. The students in turn regard him not only as a helpful teacher but a stimulating, innovative one as well. Together with Professor Norman Satl:!_er, he has de v eloped self-paced ma terial for the teaching of mass and energy Bruce enjoys backpacking with his family in the Cascade and Olympic Mountains balances and chemical thermodynamics, which are the first two courses in the under-gradu~te chemical engineering curriculum The students find these courses to be a unique and valuable learning experience. Students particularly like the personal assistance given to those who need it and the healthy exchange of ideas that occurs as students develop their own approaches to a problem. (Continued on page 23.) 3

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[eJ ;j Ii department WATERLOO M. MOO-YOUNG Universi t y of Wate r loo Waterl oo Ontario, Canada THE UNIVERSITY OF WATERLOO came into being in 1957, and after some birth pains, a nnounced its intention to be the first Cana dian university to undertake cooperative ed ucation in engineering and other professional p r og r ams. Significantly, the first building con s tructed was the Chemistry and Chemical Enginering building. Because the concept of co ope rative engineering education was new in Ca nada (although old and well tested in Europe a nd the U. S. A.), the faculty members first at tracted to the new-born institution were a group devoted to educational innovation. Indeed, the first C hairman of Chemical Engineering, T. L. (Ted) 4 Batke, went on a few years later to become Aca demic Vice President of the University, in which post he served during its early development The unprecedented growth of the University in its first decade was due almost entirel y to the immense success of the cooperative programs and to their complete acceptance and suppo r t by Canadian industry. By 1970 the University of Water l oo had the largest undergraduate engineer ing schoo l in Canada, and the second largest graduate schoo l. In emulation of our success, two other Canadian Universities have since started cooperative engineering programs. The growth in engineering at Waterloo was paralleled by the growth in applied mathematics and computer science, in which cooperative pro grams were also initiated A large part of the CHEMICAL ENGINEERING EDUCATION

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The unprecedented growth of the university was due almost entirely to the immense success of the cooperative programs and to their acceptance and sup port by Canadian ind ustry By 1970 we had the largest undergraduate engineering school in Canada, and the second largest graduate school. strength of the University is still founded in these two areas, with about 50 % of the total enrollment of 13,000 students being in them. GROWTH AND PLANNING GIVEN A NEW ENGINEERING school supported with soaring enrollment and generous government aid, the atmosphere of the early days was "Gung-ho !" and the Department grew to its present form and size in barely 14 years. In 1962 Batke left the Department to serve as Vice -P resident of the University and L. E. (Lou) Bodnar became acting Chairman. In 1964 D. S. (Don) Scott was appointed Chairman The rapid growth at this time meant that some long-range objectives needed to be formulated. The basic organization into discipline-oriented and industry oriented areas ( described later) was set up and future growth was directed towards developing excellence in them. During this period some Departmental "sacred cows" in educational philosophy also evolved: no more than two courses per semester as an average teaching load; no more than about 20 contact hours per week for undergraduates; no teaching or research area should be started or maintained unless at least 3 full-time faculty members were primarily devoted to it; about 10 % of the teach ing salary budget for visiting professors; student representation on all curriculum-related com mittees. Our basic organization remains the same today but with some modifications including the introduction of essential business -o riented and en vironmental courses In 1970, K. F. (Ken) O'Driscoll came from S. U N. Y. (Buffalo) to assume the Chairman's post. At about this time, in common with the general North American scene, the University entered a period of more limited growth. "Ma turity" has crept up on the Department and life is more stable now. The pursuit of excellence in teaching and research is a long task and as we enter maturity we feel that we are well on the way. Our family has become large, probably the largest of the 19 Canadian ChE families. The WINTER 1975 present level of activity includes 400 under graduates and 80 postgraduates, including post doctorals, and 28 full-time faculty members. UNDERGRADUATE PROGRAMS At Waterloo, the undergraduate programs are designed to teach students that responsible engineers are involved not only with the tradition al role of providing material needs but also w ith the quality of life which is affected by the creation of their processes and products. Since chemical engineers can contribute to the solutions of c ur rent world problems in health, nutrition and pollu tion, relevant course material has been built into the programs and the curriculum is c onstantl y under revision to meet changing needs. Prof. Turner (right) with specially designed equipment for measuring thermal properties discussed in his recent book A basic education appropriate for a variety of careers is stressed. Our graduates may go di rectly into jobs, continue with further studies in Science or Engineering, or as many have done enter other professions such as Medicine and La w In the early years, chemistry, physics and mathe matics form the usual foundation. Later, subje c ts such as economic analysis, design, and entre ; preneurship enable the student to reach a practical appreciation of his earlier s tudi es. 5

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Specialization is available through six options: ( 1) Biochemical and Food Engineering ( 2) Ex tractive and Process Metallurgy (3) Pollution Control Engineering ( 4) Polymer Science and Engineerin g ( 5) Transport Processes ( 6) Mathe matical Analysis and Control. At present about one-quarter of the curricu lum consists of elective courses, both technical and non-technical. Three of the technical electives are selected from one of the six options. Student-faculty contact outside of lectures is facilitated by frequent get-togethers organized View of Engineering Complex (floor space 477,035 sq ft ), ChE Dept is T-shaped section in foreground (floor space 124,626 sq ft ) by the Chem. Eng. Club, the Waterloo student chapter of the C S. Ch. E. Each class has a class professor who looks after the general well-being of each student. Class professors handle academic as well as non-academic problems, usually by referral services, e.g. Counselling, Health Services, course-tutors, banks. This particular student professor relationship is especially helpful to the first-year students. Another, probably unique feature is the final-year study-room which is "home" in the department for all seniors Each has his own desk and facilities are available for coffee, magazines, calculators, etc. CO-OPERATIVE EDUCATION T HE PREPARATION FOR AN engineering career normally involves formal academic studies followed by practical experience The co operative education system at Waterloo provides an integrated pattern of both academic study and practical experience for the undergraduate. The degree program covers almost 5 calendar years, co mprising eight 4 -month terms of academic training, alternating with six 4-month terms of practical training which brings a student into di rect contact with the engineering profession. 6 The cooperative system provides the student engineer with a career perspective and the op portunity to secure financial assistance. Work term jobs are found and supervised by the Uni versity Co-ord ination Department, which ar ranges on-campus interviews and maintains a staff throughout the country to arrange on-site details with the over 700 participating companies and agencies. Undoubtedly, the success of this program is largely due to the efficient organiza tion of our Co-ordination Department. GRADUATE AND RESEARCH PROGRAMS THE DEPARTMENT OFFERS postgraduate programs leading to the M.A Sc. and Ph.D. degrees. The minimum credit requirements for the M.A.Sc. are 4 courses and a research thesis, or 8 courses and a design project; for the Ph.D., 4 courses and a research thesis. As with other Canadian programs, these requirements represent a compromise between the British and American formats. While the undergraduate programs are all based on the co-operative education system, al most all the postgraduate programs are not. How ever, special arrangements are made for part-time and off-campus studies, which are ,, mcouraged for the continuing education of engineers. At present, in addition to on-campus evening lectures, off campus classes are given in two locations: Sarnia, Canada's largest chemical industrial complex; and Sheridan Park, the largest industrial research c ommunity in Ontario. Research at Waterloo is currently organized into five groups. Faculty members associate with these groups voluntari l y; some members belong to more than one group and occasionally some change their group affiliation as interests change. The Prof. Fahidy (left) tutors on the finer points of computer applications. CHEMICAL ENGINEERING EDUCATION

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Prof. Moo-Young (center) and research assistants with fermentor which helped to bring biochemical engineering fame to Waterloo. groups exist to co-ordinate course offerings and to optimize the use of equipment, space and graduate-recruiting facilities. The current areas of research are shown below. BIOCHEMICAL AND FOOD ENGINEERING GROUP Mass transfer, heat transfer, mixing, cell-growth and enzyme kinetics in biotechnology. Design of fermentation, food processing and waste treatment facilities. Hydro carbon and cellulose fermentations, food rheology, micro bial proteins, immobilized enzymes, manure utilization. (Moo-Young, Robinson, Scharer, Silveston, O'Driscoll) EXTRACTIVE AND PROCESS METALLURGY GROUP Pyrometallurgical, hydrometallurgical and electrometal lurgical processes. Solvent extraction, ion exchange, leach ing, inorganic chemistry, theoretical high temperature metallurgy. (Byerley, Enns, Rempel, Spink, Wynnyckyj, Fahidy, Scott) POLYMER SCIENCE AND ENGINEERING GROUP Diffusion through modified membranes, radiation graft polymerization, emulsion polymerization, stress relaxation in elastomers, adhesion, polymer compatibility, kinetics and thermodynamics of polymerization reactions. (Burns, Huang, O'Driscoll, van der Hoff, Macdonald) MATHEMATICAL ANALYSIS AND CONTROL GROUP Simulation, process control, applied statistics, computer control, process analysis and dynamics, operations re search, optimal design and control of chemical plants. (Chang, Fahidy, Gall, Mueller, Reilly, Rhodes, Heatley) TRANSPORT PHENOMENA AND KINETICS GROUP Heat and mass transfer in multiphase systems. Con current flow transport processes, boundary layer theory, turbulence at mobile interfaces, frequency response WINTER 1975 methods, diffusion. Reaction rates in inorganic and organic systems, selectivity studies in catalysis, diluent gas effects. (Batke, Bodnar Dullien, Ford, Hudgins, Macdonald, Pei, Rhodes, Scott, Silveston, Turner, Moo-Young, Robinson) In addition to the above five groups, there is a nascent Environmental Engineering group which presently draws on the relevant ex pertise of the other groups. As with the undergraduate pro grams, the department is organized to move rapid ly with the restructuring of its research groups as dictated by student need and faculty exper tise. It should be also noted that interdisciplinary pro grams are available with such departments as Chemistry, Biology a nd Management Science. Research laboratories covering over 50,000 sq. ft. of space are housed in a modern, air-condition ed building. The w ide range and diversity of equipment have never failed to impress visiting ChE faculty. One recently tried to see it all in one day with the result that he found himself "completely dehydrated" at the end of a gruelling tour. A departmental Reading Room, a glass-blow ing shop, machine-shops and an electronics-shop The programs teach students that responsible engineers are inv olved not only with the traditional role o-f providing material needs but also with the quality of life further extend the research facilities. The Uni versity Computer Centre also contributes greatly to the departmental research facilities. FACULTY PROFILES THE OVERALL QUALITY of a department is determined to a large extent by its faculty members. Ours have a diversity of cultural and education backgrounds that we treasure. Faculty Ph.D's are from 19 different universities repre senting 5 different countries. As quote d in the report of the "Advisory Committee on Academic Planning," Council of Ontario Universities, Sept. 1974, "This is c ertainl y an extremely important factor in enriching the collective way of thought and methods of training students in the depart ment ... There is a large group of very produc tive people (in research) and there is an excellent spirit of cooperation among the staff, providing a stimulating milieu for students." To give an idea (Continued on pa ge 39.) 7

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_ iib:lviews and opinions ChE LAB: A NEW LOOK J.M. DOUGLAS University of Massachusetts Amherst, Massachusetts 01002 T HERE HAS BEEN A considerable amount of discussion of chemical engineering laboratory courses taking place at national AIChE meetings for the last several years. The multiple, educa tional purposes of these courses have been de scribed in some detail, and included in these goals are: to familiarize the student with chemical processing equipment, to help the student gain proficiency with instruments and measurement methodology, to teach students how to deal with experimental errors, to allow students to practice technical report writing, etc. Another major goal, not included in the abbreviated list above, is to show that the experimental data agree with the theory that the student has learned in his courses. In actual fact, however, very few of the experi ments do agree with the theory, and so the student is required to find reasons for the discrepancies and to discuss his reasoning in his laboratory re port. At this point, students normally engage in an exercise, which I call "creative B. S." They demonstrate an imaginative capacity far exceed ing even the wildest science fiction authors, in order to find some justification of why the equip ment did not work properly. Although I think it is always worthwhile to find ways to excite the imaginations of students, I am somewhat worried that we are doing this in the wrong context. In addition it seems to me that it is a dangerous pedogogical practice to have students carry out an experiment to verify a theory. If they are not successful in their attempt, they can easily draw the conclusion that the experiment (reality) is no good, while the theory ( an abstraction) is correct. Thus the theory becomes a better de scription of reality than the experiment, which becomes unreal. Obviously, faculty would not agree with this conclusion, nor am I certain that students accept it either; but perhaps much of the dislike students often have for laboratory courses is caused by this hidden conflict. 8 Editor's Note : The following pages deal with the chemical engineering laboratory We begin this special laboratory issue with a provocative article that suggests a new approach to our laboratory courses. A better approach to laborator y experimentation might be to ask students to develop a theory to describe the behavior of a particular piece of laboratory appara tus With this approach they would need to know not only the results of the simple theory discussed in their courses, but also to have a good understanding of the assumptions behind that theory. Then, when the simple theory fails to predict the observed behavior, the students would have to determine which one, or more of the assumptions were not valid and to modify these assump tions in an attempt to develop a more realistic model. In this way they would evolve a workable theory. Although this approach is more time con suming than a traditional experiment and is much more difficult (it requires a great deal more thought on the part of the student) it should give them an improved understanding of the re lationship between theory and practice. In particular, some clever students may recognize that there are alternate approaches to the prob lem; some groups may attempt to redesign the equipment so that the assumptions for the simple theory are satisfied, others may develop a set of correlations to provide correction factors for the simple theory so that it agrees with the observed data, and others may develop more sophisticated theoretical models. Thus, the class would learn that there are no unique solutions to engineering problems, they would gain additional insight into the differences between interpolation and extra polation, and they w ould have a better apprecia tion for the real world they will encounter when they leave the university. As an alternate approach to resolving the discrepancy between experimental observations and simple theories, the student could be asked to develop a trouble-shooting procedure for a particular piece of equipment. That is, he would be assigned a task of devising a way of im proving the performance of the syste m (assu min g that the simple theory predicts a better performance than that exhibited by the equipment) or to determine why CHEMICAL ENGINEERING EDUCATION

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the existing equipment fails to meet the designed specifi cations (where the design is based on simple theory). Problems of this type will be more time consuming than conventional experiments but they have the advantage of exposing students to some engineering concepts that are not normally treated in the curriculum, such as the time and cost required to make additional measurements or to modify existing equipment, the use of intuition rather than theory to design flow distributors and other apparatus the difficulty of communicating your ideas clearly to technicians, etc. SOL V ING ENGINEERING PROBLEMS ANOTHER GOAL THAT APPEARS to be lacking in laboratory courses is the idea of solving engineering problems experimentally. Most of the effort in chemical engineering curricu la is directed toward analysis, and we describe successively more sophisticated theories for solv ing selected engineering problems. Laboratory courses are used to demonstrate the validity of these theories, more or less, and the design course is used to introduce the ideas of synthesis, as well as to integrate the previous courses in analysis. Depending on the individual who teaches the design course, I'm certain that there is some discussion of how to select the "right" tool to solve a particular problem, although none of the design texts that I am familiar with treat this topic. Moreover, I doubt if there are many design courses that are so closely integrated with a laboratory course that students ever gain much feeling for how to decide whether to take an ex perimental or theoretical approach to solve a particular problem. One method we might use to help students understand the limitation of simple theories, the relationship between theory and practice, and the relative effort associated with both experimenta tion and analysis, is to orient at least some of the laboratory course more toward the solution of engineering problems. For example, we could ask students to develop correlations for head losses in pipe fittings, pump efficiencies, film heat-transfer coefficients, etc. for a non-Newtonian fluid. It should be easy to find examples where Newtonian data are available in the literature, but the cor responding results for a power-law fluid, for example, are lacking. Moreover, it shol<:l be re latively simple to convince students of the poten tial applicability of the results, so that perhaps they will become better motivated towards ex perimentation. Of course, before taking data with a non-Newtonian fluid, it would &eem reasonable WINTER 1975 to attempt to reproduce the reported results for Newtonian fluids (which would mean that we would carry out many of the normal fluid mechanics and / or heat transfer experiments in a context where they were a means to an end, rather than an end in themselves). In addition, a focus on non-Newtonian fluids might make it possible to develop a better integration betweei1 lecture and laboratory courses by deriving the ap propriate solutions for simple flow configurations and demonstrating the extension of dimensional analysis for complex systems in the lecture for the systems that will be studied in the laboratory. Still another concept that is probably best presented in a laboratory context is that most engineering problems must be approached in an iterative fashion, that it is necessary to know the answer to a problem, at least ap proximately in order to formulate the problem. Thus if we recognize that we will be forced to solve real engineer ing problems more than once, (in contrast to text book problems), we want to start with very simple, even though crude, predictive methods, and then proceed to more sophisticated algorithms as long as there is an economic incentive. As a simple although possibly painful, illustra tion of the importance of this "engineering method," we could ask students to develop a statistical experimental design for a batch reaction system where they have difficulty in finding any published information on the approximate half-life or reaction rate period. Indeed, an assignment of this type might provide an interesting "academic" experiment of how much engineering intuition students gain from an engineering education .. It is a dangerous pedogogical practice to have students carry out an experiment to verify a theory. If they are unsuccessfu l they can easily conclude that the experiment (rea l ity) is no good while the theory (an abstraction) is correct. CONCLUSION In conclusion, perhaps I should admit that it is always easy for a poor experimentalist like myself to criticize the efforts of others. Also, I recognize that the program I a m proposing calls for more sophistication on the part bf the student than our traditional laboratory courses. How ever, perhaps a portion of the class would respond more favorably to an open-ended laboratory such as I suggest, and the remainder of the students could do the convention al experiments. Another advantage of the laboratory is that' it may produce some data which prove to be useful to the profession, and thereby encourage more contact between the university and industry. O 9

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[iJ n a laboratory FLOW CURVE DETERMINATION FOR NON-NEWTON I AN FLUIDS WALTER P. WALAWENDER and T. Y. CHEN Kansas State Uni ver sity Manhattan, Kansas 66506 T HIS REPORT DESCRIBES a student laboratory experiment for the determination of the flow curve of a non Newtonian fluid using a capillary viscometer with continuously varying pressure head. The experiment exposes the student to the concepts of non-Newtonian flow analysis, as well as non linear parameter estima tion techniques. Computer aided data analysis is included as part of the experiment. APPARATUS AND PROCEDURE The viscometer is shown schematically in Fig. 1. It is a modification of one described some years BURET JACKET TEW E l!:.\TURE ( REGULATOR R I NG STANO COLL E CTrNG FLASK WA T ER M n+ F i o I Sche ma tic d i a o ram a f the a p par atus 10 THERMOMETER ago by Cerny [l]. The instrument consists pri mar i ly of a precision bore capillary A and a 50 c c buret B. The capillary A is placed horizontally with one end inserted into a rubber stopper which is sealed to the collecting flask F and the other end connected to the buret B by means of a piece of tygon tubing. The pinch clamp C is a convenience for filling the viscometer. The flask F has a side arm which is extended ~ with a piece of tubing to the atmosphere The buret B is jacketed by a 2..: i nch dia m eter glass tube. The water bath is kept at a desired temperature by a regulator G. The regu l ator unit contains a pump which is used for circulation of water through the jacket. This arrangement assures constant temperature for the measurements. In operation, the buret, connecting tubing and cap ill ary are filled with the test fluid and the clamp C put in place. Care should be taken to avoid trapping bubbles in the line. Generally the buret is filled well above the top graduation. If the test fluid is not at the bath temperature, about 10 minutes should be allowed to bring it up to bath temperature before starting a run. A run is started by opening clamp C, permitting the fluid in the buret to flow through the capillary. A stop watch with a split hand feature is used to time the descent of the meniscus in the buret at selected graduations (i.e. 0, 5, 10, 15, ... ) The times corresponding to the selected graduations are re corded. Readings can be taken until the meniscus passes the last graduation on the buret or until the descent of the meniscus is too slow to be measurable. A minimum of three sets of gradua tion (x) versus time data are taken for a given sample. An average of the three sets is used for data analysis. SUPPOR TI NG DA TA T HE LENGTH OF THE capillary is measured directly. The capillary radius is determined by filling it with mercury, weighing the thread of mercury, and calculating the radius from the C HEMI C AL ENGINEERING EDUCATION

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Walter P. Walawender is an Assistant Professor of Chemical Engineering at Kansas State University He received his under graduate training in Chemistry at Utica College and his M.S. and Ph D degrees in Chemical Engineering from Syracuse Universit y. His current res e arch interests include modeling of blood flow i n the microcirculation and gasifkation of agricultural wastes H e teaches a v ariet y of courses at both the graduate and undergradu ate level. Te Yu Chen r ec e i ved his bachelor's degree from National Taiwan University a nd his master's degree from Kansas State Univ ersi ty, both in Chemical Engineering He is a graduate research assistant at KSU His current research ar e as are fluidi z ation and the gasification of agricultural wastes volume of the thread. The volume is given by V = (mass of Hg) -:(density of Hg at measurement temperature). The radius then follows from R = (V / 1rL) 1 1 2 A minimum of three determinations are recommended. The buret cross section is determined by measuring the distance between terminal gradua tions (i.e. h 0 h 5 o ) and dividing the buret volume by this result. A= SO/ (ho hso) A relation between the buret graduations and the height of the meniscus relative to the capillary outlet is also required for data analysis. Noting the buret graduation as x and the measured distance between the last buret graduation and the capillary outlet as (h 5 o h 0 ), the following expression can be written h = _5_0_-_ x A (1) This gives the height of the meniscus relative to the capillary as a function of the buret graduation reading x. The test fluid density, if unknown, is deter mined at the bath temperature with the aid of a pycnometer WINTER 1975 THEORETICAL THE FLOW SITUATION of the present viscometer is very similar to that of a problem presented by Bird et al. [2]. Hence a quasi steady state approach is used for the theoretical analysis. The theoretical development for Newtonian flow in this viscometer has been discussed by Cerny [1] and is outlined below. This will be followed by the analysis for non-Newtonian flow. The flow of a Newtonian fluid in a capillary tube is described by the Poiseuille, equation, L\ P = 11 R lf (2) This expression relates the pressure drop 6 P across the capillary (of radius Rand length L) to the volume rate of flow Q and the coefficient of viscosity 'Y/ For the viscometer the pressure drop at any moment is also given by L\ P = p g h (3) where h is the height of liquid colu mn in the buret relative to the capillary, p the fluid density and g the acceleration of gravity. The volume rate of flow at any moment can be expressed as dh Q = A dt (4) where A is the cross sectional area of the bur et. The experiment exposes the student to the concepts of non-Newtonian flow analysis as well as non-linear parameter estimation techniques. Computer aided data analysis is included as part of the I experiment. The combination of equations (2), (3) and (4), followed by integration results in an expression re l ating h and t ln h = 71 R 4 P8 t + C 8LATJ where ~ B BLA and m = TJ (5) mt+ C Thus a plot of log 10 h versus t shou ld be linear. The viscosity of a Newtonian fluid can be evaluat ed from the slope (m) provided that the instru, 11

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mental dimensions and the fluid density are known. In the case of a non-Newtonian fluid, the "vis cosity" is not constant and varies with the rate of flow or more properly the rate of shear. The log h versus t plot gives a curve with m varying from point to point. This variation can be utilized to relate the wall shear rate 'Y w to the wall shear stress r w from which a flow curve Tw versus 'Yw can be constructed. An approach similar to that developed by Krieger and Maron [3] is employed. The experiment described in this report provides for student exposure to non-Newtonian flow as well as computer aided data analysis. Several types of fluids can be employed to illustrate types of flow behavior First, an effective fluidity is defined, with reference to equation (2) as 1 :, e 11 e (6) where Y/ e is the effective viscosity. From the ex pressions in equation (5) it can be seen that is given by m cjJ e = :3 p (7) Under conditions of steady, laminar flow of a time-independent fluid through a cylinclrical tube, it can be readily shown [4, 5] that T 2 lo w T f( -r ) d -r (8) where Rl\ P T =W 21 f ( -r ) y (9, 10) Combination of equations (6), (8), and (9) gives (11) Differentiation of equation (11) with respect to 12 T w using Leibnitz's rule and rearrangement of the result gives t w T w A, (1 + 1 'l' e 4 d ln e. d ln -r J w (12) The terms in


PAGE 15

taken as the negative value of the slope of a line fitting tne first few points of the In h versus t plot. An initial guess for the parameter c is taken as 2. The parameters a and b can then be estimated as the intercept and the slope of the least-square-fit line of a v 8 versus t plot, respec tively, with 8 defined by o = ln h ln h + kt 0 (16) Only a rough estimation for these parameters is sufficient and this can be easily done on a pro grammable desk calculator, or available computer program such as the IBM scientific subroutines package. Both upper and lower bounds must be supplied in the input. The determination of these bounds is somewhat arbitrary. The bounds as suggested from this study are the following, 1~ k: initi a l g u es s x (1.00 0. 3 0) 2) 3) a: b: 0 < i a l < 0.1 0 < b < 0.01 4) c : 1 < C < 5 (17a) (17b) (17c) (17d) where the upper bounds of \ a \ and b are arbi trarily chosen as one order of magnitude greater than the values ordinarily encountered. The parameters estimated by the c omputer program can be used to analytically evaluate m and dm/dt. From equation (15), d l~ h ( c 1 m = -= k + c b a +bt) dt From equation (18), dm / dt results, dm dt 2 c2 = c(c-1) b ( a + bt) (18) (19) For the special case of slight curvature of the In h versus t data one can generally obtain a satis factory description of the data by setting c = 2. This reduces the computer time required and eliminates one parameter from the parameter esti mation. Substitution of equations (18) and (19) into equation (13) gives an expression for Yw / rw in terms of the parameters. The evaluation of m, dm / dt, T w and Y wlrw can be done on the computer with a slight addition to the original Bard's program. In this way, the flow curve in,:, u is apparent that 8 repr ese nt s th e d e viation of a In h versus t plot from linearity. Thi s deviation usually i s a quadratic function of t. Accordingly, equation (15) was formulated. WINTER 1975 Table l. Resu lt s for th1c: test f l uid Tim"' t h .ln h exp' 1 ,12 h cal
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indicated by equation (16). The values of 8 and / f; are tabulated in columns 4 and 5. The \/ 8 data are used for the initial guesses of parameters a and b. The ('/8 versus t) data are fitted by least squares with the aid of a programmable calcula tor. The resulting intercept and slope give the initial guesses of a and b, respectively. These values are presented in Table 2. Bounds for para meters calculated by the program are also shown in Table 2. These parameter values are used in the program to calculate h values by equation (15). The resulting h values are presented in column 6 of Table 1. A comparison between the best fit curve and the experimental data is given in Fig 2. As can be seen from the figure the fitted ,. 1 0 filled C urv e 0 Data Points 7 0 100 200 300 400 500 600 7 00 800 900 Tlme,,ec Fig 2 A typical fitted curve for h "' t data curve describes the experimental points very well. The error in h cnld, as can be seen in Table 1 never exceeds 1 % Next T w and 'Yw, as given by, T -~ w 21 and y = -in { l + _l_ dm} w T w Bp 4 m 2 dt (15, 13) are evaluated, using the estimated parameters. Here h, m and dm / dt are given in terms of the parameters by equations (15), (18) and (19). 14 The results are shown in column 7 and 8 of Table 1 as well as in figure 3. As shown in Fig. 3. the shear rate range from a single determination covers about one cycle. The fl.ow curv e of non-unit slope indicates the non-Newtonian behavior of the test-fluid. 100,--------------------, / line of unit slope / // 0. data points / / IIO / / / / .. E u > C >'O / ..... / / / / / / ID / IOO !!00 IOOO 2000 1w, sec1 Fig 3 The flow curve STUDENT RESULTS S EVERAL STUDENTS c onducted the experiment with a 0.05 % (wt) so lution of CMC in water. The ca pillary employed was 19.88 cm long and had an inside diameter of 0.1020 cm. Reproducibility of the raw data (x vs t) was quite g ood with agreement within % on the total flow time of approximately 750 seconds. For this fluid, the parameter c cou ld not be taken as 2 and was estimated along with the other parameters. A typical h versus t curve is sh own in Fig. 4. As can be seen the agreement i s quite good. A typical flow curve is shown in Fig. 5. For the CMC sample employed, one can observe the trend towards the "zero s hear limiting viscosity by replotting the data in the form of 'Y/ versus y ('Y/ = 7 / y) fi ll ed curve GI da t a l)Jinb !c, --,------,.!""'S------,,_ ___.,, ""--~ ,., T i me s e c """' Fig 4 H vs t. CHEMICAL ENGINEERING EDUCATION

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SUMMARY JN SUMMARY THE experiment described in this report provides for student exp o sure to non-Newtonian flow as well as computer aided data analysis. Several types of fluids can be em ployed to illustrate the various types of flow be havior. In utilizing this experiment it is suggested that several diameters of capillary be available in order to ensure reasonable experiment length (total flow time) as well as to provide for greater variation in shear rate. .f 10 .. .. .. .. ... ~oo ~ _..__._--'-~ ~ -'-'--~ = ~---'--....,__.__~~~~ ,~= r secFig 5 Flow curve for CMC solution ACKNOWLEDGMENT This work was supported in part by a grant from Ka n sas Heart Association #K R-72-10 This support is grate full y acknowledged. The efforts of the junior C hemical Engineering stu dent s (1973-7 4) in testing the experiment are greatly appreciated. LITERATURE CITED 1. Cerny, L. C Am. J. Phy s ., 29, 708, 1961. 2 Bird, R. B., Stewart, W. E., and Lightfoot, E. N ., Transport Phenomena, p. 237, problem 7.M, John Wil ey & Sons, Inc. New York, 1960. 3 Maron, S. H., Krieger, I. M and Si sko, A. W., J. Appl. Phy s., 25, 971, No 8, 1954. 4. Skelland, A. H. P. Non-Newtonian Flow and Heat Transfer, John Wiley & Sons, Inc., New York, 1967. 5 Wilkinson, W. L., Non-Newtonian Fluids, Pergamon Press, London, 1960. 6 Bard, Y., "Non-linear Parameter Estimation and Pro gramming," IBM New York Scientific Center, De cember 1967 APPENDIX A printout of the computer program is avail able. It consists of seven decks ; a main program and six subroutines. Definitions of the variables added are given in the comment statements. Names of the other subroutines are given to show the entire structure of the program. For details of the entire technique, reference can be made to Bard's original manual [6]. ARE YOU APPLICATIONS ORIENTED? At Fluor Engineers and Constructors, Inc. our 4 billion dollar plus backlog offers all kinds of practical applications opportunities for chemical engineers to help provide solutions to the energy problem. At Fluor Engineers and Constructors, Inc. we de sign and build facilities for the hydrocarbon processing industry-oil refineries, gas processing plants, and petrochemical installations. We are very active in liquefied natural gas methyl fuel, coal conversion, and nuclear fuel processing. If you want to find out about opportunities, loca tions you can work in (world wide) and why Fluor is the best place to apply what you have learned, meet with the Fluor recruiter when he comes to your campus or contact the College Relations Department directly. Fluor Engineers and Constructors, Inc. 1 001 East Ba II Road Anaheim, CA 92805 ,'( FLUOR ENGINEERS ANO t CONSTRUCTORS, INC. WINTER 1975 15

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TEACHING PROCESS SYNTHESIS -The Integration of Plant Design and Senior Laboratory K. A. OVERHOLSER, C. C. WOLTZ, and T. M. GODBOLD Vanderbilt University Nash vi lle, Tenn essee 37235 THE CURRENT ATTEMPT at Vander~ilt University is to organize our undergrad1ate chemical engineering curriculum around process synthesis and design, rather than around tr t ns port phenomena or the tradi!ional unit operatt~ns sequence. The students acqmre a firm founda p on in the engineering sciences of mechanics, thermo dynamics, and the transport and electrical phe nomena, but the emphasis in the ChE b ore courses is on design, beginning with flow sheet generation in the sophomore "stoichiometry" course and culminating in the senior plant de f ign project. Such an approach requires a caireful effort to develop problems and case studies, / but we feel that the effort is justified by a closen ap proximation to modern ChE practice. Until recently, the laboratory courses have I not contributed directly to this curriculum. rhey have tended to emphasize the understandin f of physical principles, report writing, team work, and the development of planning and reas 3 ning abilities, but they have done so through a s~ries of self-contained experiments which were a]l too often unrealistically well defined. Nevertheless, a second-semester senio ~ de velops a curious enthusiasm for his ChE la p ora tor y work. He sniffs the air, realizes what may be expected of him in a few months, and begips to approach his laboratory work in mature and pro ductive fashion. We saw an opportunity to combine the phe nomenon of senior lab motivation with our design emphasis. It seemed particularly appropriate to seek the close involvement of industry. This paper describes our first serious attempt to combine laboratory work, industrial contact, and "plant de sign" into one five-semester hour course. We as signed, with the help of chemical engineers and chemists in local practice, a semester -lon g process design for which data might be unavailable. The students had to decide what information to obtain in the laboratory, perform the appropriate experi ments, complete their process design, and report to their industrial and faculty advisors. Because many other schools are moving toward a design oriented curriculum, we felt that our experience might supply some insight into the advantages and disadvantages of an integrated laboratory design approach. COURSE OBJECTIVES W HEN ':I'E COMBINED course was in the plannii'.i.g stages, we identified five objec tives: First, we hoped that the students could gain some confidence in their ability as engineers. In order for this objective to be realized, we would have to pick a difficult project with a good chance of successful completion. If the class could com plete such an assignment, they would justifiably feel a sense of accomplishment and pride. It was important that the assignment not be totally artificial, but be as realistic as possible. Second, we wanted the students to see the real The integration of plant design and lab was so j successful t~at we see no reason to return to our old system We enthusiastically recommend tre joint lab design approach. If you try it, you might consider four points which we feel to be of p l aramount importance The cooperation of an accessible industry is essential; a suitable problem must be chosen; a great deal of advance planning is necessary; consider your equipment constraints 1 in advance planning is necessary. Consider your equipment constraints in advance. 16 CHEMICAL ENGINEERING EDUCATION

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utility of engineering experimentation. Instead of requiring the students to spend one afternoon a week verifying physical laws or measuring proper ties, they would be expected to resort to labora tory work only when the data required for the plant design could not be obtained from alternate sources. They would have to decide what informa tion was needed. They would have to design the experiments. Our third goal involved the development of the managerial skills required to efficiently carry out a long, complex project. It is important for young engineers to learn how to organize and communi cate among themselves. Next, we hoped that the lab would help give a physical feel for the plant design project. Most of us, when assigned an engineering job, have at least seen the materials and processes with which we are asked to work. This is rare ly the case in a senior design project. Finally, we hope to develop contact between the students and practicing chemists and chemical engineers, contact based on technical matters of joint interest. Seniors want this contact; too often they get it only in job recruitment situations. THE PROBLEM T HE PROBLEM WAS PRESENTED to the students at the first plant design session and during the first lab period in the following form: Design a plant to produce 100 million pounds of polyester melt from the raw materials DMT and ethylene glycol. The plant is to be located on a 1000 acre spread on the C umberland River near Nash ville, Tennessee." The process to be used was basically that of the DuPont Old Hickory Plant. This facility produces Dacron (polyethylene terephthalate) from nitric WINTER 1975 K. A Overholser, the laboratory instructor in this project, re ce ived his Ph D. in chemical engineering from the University of Wisconsin and was a N.A T.0. postdoctoral research fellow at Im perial College, London His research activities include hemorheology and combustion physics. {Left ) C. C. Woltz was the student project leader. He i s now a gradu ate student in chemical engineering at Vanderbilt. (Left above ) T. M. Godbold instructor for the Plant Design course, received his B .S. and M.S. from the University of South Carolina and his Ph.D. from North Carolina State Uni ve rsity He has industrial ex perience with DuPont and Celanese and has been a consultant for several companies. His areas of interest include process control and diffusional operations. (Right above) acid, xylene, methanol, and ethylene glycol. Para xylene and nitric acid react to form terephthalic acid which is then combined with methanol to form dimethyl terephthalate (DMT). The DMT is fed to transesterification reactors where it is com bined with ethylene glycol to form methanol and ester monomer (bis-hydroxyethyl terephthalate, or BRET). The monomer is polymerized under vacuum, yielding ethylene glycol for recycle; th~ resulting highly viscous polyester melt is spun and packaged Some initial ground rules were stated: The entire ChE faculty will answer all questions to which they know the answers and will supply any fac tual information to which they have ready access. The students were encouraged to make use of all of the faculty as consultants. The DuPont staff will help and answer questions within proprietary limitations. Any of the ChE lab and computer facilities may be used at any time, subject to our safety rules. The library and the patent files should be used as ex tensively as time allows. Don 't take data jn the lab if you can find it (and trust it) else, v here. Data and information discovered by anyone will be made available to the class as a whole. 17

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Each student must design his own plant, although st~ dents may work together until all laboratory data r quired are obtained. The class was given a supply of raw DMT by DuPont. The firm also supplied a small quantity of recrystallized BRET for quality comparisohs and determination of physical properties. The ChE Program supplied antifreeze fr9m which the class could obtain ethylene glycol if they so chose. ... a second-semester senior develops a curious enthusiasm for .. laboratory work. He sniffs the air, realizes what may be expected of him in a few months, and begins to approach his lab work in mature and productive fashion. From this point until the end of the semester the class was on its own in the design and 1ab project, receiving only occasional unrequested advice from the faculty. CLASS MEETINGS THE PLANT DESIGN PORTION was offered for three semester credit hours. In the 1rst third of the course (while the lab was geting started), the students reviewed and practced equipment sizing and design decisions on sev ral ~ase st~dies .. Although the class had had a co~rse m Engmeermg Economy, methods of econo;mic analysis and optimization were briefly reviewed and expan?ed to meet _the anticipated needs of / the Plant Design. The primary texts for this co1rse were Perry's Handbook [1] and Peters and 1 im merhaus [2]. During the latter half of the semester, the class did not meet formally, but tu den_ts were strongly encouraged to meet with / the design professor once a week to discuss derign problems and report their progress. This weekly meeting prov ided an opportunity to discuss d1 I ign and lab progress as well as exchange informa ion. The Laboratory portion met once a week rom 8 a.m; to noon. All lab work was devoted t~ the design project. Each session began with c ffee, donuts, and a report meeting, after which the students would begin experiments, librar~ re search, or planning. It was often necessarr to work additional hours outside of this period. I The 18 students had obtained much of the physical property data that they needed about six weeks before the end of the semester. The overall process flow sheet was fixed by discussion at this time and the students began sizing equipment for their design. Laboratory data on the kinetics for the process was completed about three weeks be fore the end of the semester. At that time, the lab stopped meeting formally. CHAOS AND ORDER THE FIRST TWO LAB meetings were, predictably, mixtures of order and chaos. The problem was laid before the class, a temporary discus sion chairman was appointed, and the group was left on their own to lay plans. After an hour or so, the group decided to go to the laboratory and get started (they planned to measure the melting point of DMT). At this point the laboratory instructor established an ap parently arbitrary rule: Even though thi s is a lab course, no one ma y go to the lab for the first two weeks. (Note that intervention was essential at this point-left entirely to their own devices in the initial planning stages, the class might well have embarked on a course which would surely have led to failure in the end.) The students were thus forced back on the track, and they finally got around to posing such questions as "what do we need to know in order to design this plant?" and "How can we find the information we require?" The discussion proceeded relatively smoothly through the next four hours. The instructors did not participate, except to supply factual informa tion as requested, but did assign a new discussion leadei' every forty minutes. By the end of the day, after much backing and filling, it had been decided that the following information would be sought: Kinetic and thermodynamic equilibrium data for the r~action of DMT and ethylene glycol over a range of different temperatures, initial concentrations, and catalyst co ncentrations. Kinetic data for the polymerization step. lnf~rmation on the nature of polymerizers and stirring mechanisms Infor~ation on possible catalysts for the DMT / glycol reaction so that a suitable catalyst might be selected. Ph!sical properties (viscosity, melting and boiling pomts, thermal conductivity, specific gravity) and thermodynamic data (heats of fusion, vaporization solution, and reaction) for all components and mix~ tures involved. CHEMICAL ENGINEERING EDUCATION

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Heat transfer coefficients for the process strea m s. Methods for analyzing the sa mple s from reactor ex periment s Phase equilibrium data for the g l ycol -methanol-DMT syste m. Costs of raw materials utilities, transportati on etc. Information on appropriate safety precautions against burns, fires and dust explosions (these and other haz ards were identified at the outset by the instructors and by the industrial advisors). The c lass split into three groups, each group taking responsibility for obtaining some of the data in the above list. The Kinetics group was responsible for identifying and gathering all in formation necessary for the specification and de sign of the transesterification reactor. The Sepa rat ion s group took responsibility for all labora tory separations ( e.g., separating ethylene glycol from antifreeze) and for obtaining information relevant to the process separations The third group was responsible for obtaining all physical properties which might be needed to ~stimate heat transfer coefficients and friction factor_s. They were also charged with devising laboratory analytical procedures and with analyzing samples generated by the other two groups. This third group was called FHA (flow, heat transfer, and analysis) group. The lab instructor picked a team leader for each group based on past performance and on performance during the initial discussion period. One student was charged with the respo nsibility of coordinating the three groups, acting as liaison between students and faculty, and setting up a timetable to insure that all data wou ld be obtained before the end of the semester. The organizational structure is shown in Figure 1. REPORTING SYSTEM E FFE CTIVE COMMUNICATION was par ticularly important in this project. It was esIt was ~ecessary for the instructors to guide the group away from a proposed semi-infinite series of univariant experiments. To avoid excessive experimentation, the group chose to plan their work using an incomplete factorial method WJN'.l'ER 1975 s INDUSTRIAL LABORATORY DESIGN CONSU LTANTS PROFESSOR ,___ PROFESSOR (KAO) I '------I KINETICS GROUP LEADER 2 E N GINEERS PROJECT LEADER (CCW) SEPAR ATI ONS GROUP LEADER 2 ENGINEERS COURSE ORGANIZATION Figure I (TMG) I I F. H A GROUP LEADER 2 ENGINEERS sential, for example, that the necessary experi mental equipment and sup plie s for a week's work be set up beforehand. The project and group lead ers had to anticipate their needs and communi cate them to the lab instructor and shop tech nician. Since each student had to design his own plant in the end, it was essential that he under stand where the data were coming from and learn how the other gro ups were solving their problems. To accommodate these communications needs, a reporting system was set up. Once a week, each group member would submit a short written re port of last week's results and this week's plans to his group leader, who would read them, add a cover report of his own, and pass them on to the student project leader. The project leader met with the lab professor each Friday afternoon to discuss reports and problems and to compare progress to the timetable Group leaders and group members were often asked to attend these Friday meetings. In addition to the written reports, short oral reports were given by representat ives of each group at the beginning of each lab period. LABO~ATORY WORK Kinetics Group Based on a preliminary library investigation and on a limited acquaintance with the DuPont proce ss, the Kinetics group identified three 19

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variables upon which production rate might de pend and set ranges over which they would take data on the reaction of DMT and glycol to form BHET. These ranges were: Reactor temperature: 180-200 C Manganese acetate catalyst concentration: 175-275 ppm Reactor feed mole ratio: 4 :1 to 6 :1 mole glycol/mole DMT Time was not available to investigate the effect of pressure and different catalysts. It was necessary for the instructors to guide the group away from a proposed semi-infinite series of univarient experiments. To avoid ex cessive experimentation, the group chose to plan their work using an incomplete factorial method. The reaction was carried out in two electrically-heated, stirred, batch reactors at constant pressure. The concen tration of BHET as a function of time was determined by condensing the methanol and measuring its volume as it was evolved The reactor system was quite complicated and plagued with problems such as non-isothermal ope ration, lo ss of methanol and boil over of ethylene glycol. The students also got bogged down a few times in the kinetic analysis of their data. The kinetics group finally obtained thirteen sets of smooth concentration-time data. Their library search, meanwhile. had turned up one appropriate study of the kinetics of their reaction [ 3 ] The reaction rate equation proposed in the reference, however, was found inadequate for conversion levels above 85%; it was necessary for the students to fit their own rate expression. They proposed a model involving a monosubstituted intermediate. The model was found to fit the data quite well, even at high conversions. A computer program was written to integrate the set of differential equations. Given molar feed ratio, catalyst concentration, reactor temperature, and physical properties the program predicted per cent conversion and rate of BHET production. It was invaluable in later repetitive attempts to seek optimal plant design. An energy balance around the reactor re vealed that the heat of the transesterification step was approximately 115 Kcal / mole DMT. This value along with the kinetics computer programs and some qualitative information on similar re actors as found in the literature, was all that the students felt was needed to design the ester ex change reactor. Since the necessary equipment was unavail able, the polymerization reaction could not be studied in the laboratory. Fortunately, the stu dents found a paper [4] and a patent [5] with the essential information. Separations Group This group had no difficulty obtaining the 20 ethylene glycoi from antifreeze, and they rather quickly located vapor-liquid equilibrium data for the methanol-glycol system [6]. A series of glass ware experiments revealed that the presence of DMT should have little effect on the design cal culations for the separation of methanol and gly col. Since their work was finished early, the Sepa rations group spent the rest of the semester help ing the other two groups. FHA Group The most important task of this group was to obtain enough information to enable the class to size the heat exchange equipment and pipes and pumps. They realized from the start that the job was most efficiently accomplished not by designing and building special devices for measuring heat transfer coefficients, friction factors, etc., but in stead to measure or find physical properties (particularly for mixtures) and use presently design correlations. The physical properties of the glycol were easy to find, the properties of molten DMT a bit less so. It was necessary to measure many of the pro perties of BHET and almost all of the properties of glycol / DMT / BHET mixtures over the relevant temperature and concentration ranges as specified by the Kinetics group. Melting points, densities, heat capacities, and viscosities were measured. Interesting experimental problems resulted from the relatively high (250 C) temperature involved. All three groups were successful in obtaining The students ... saw a finished piece of work; they performed in a mature, professional fashion; and they demonstrated a strong sense of accomplishment and pride after their presentation to industry .. the data needed in the design project before the end of the term. The data, along with useful cor relations found in the literature, were compiled by the group leaders and distributed to the class. FINAL REPORTS EACH STUDENT SUBMITTED a formal, written design report at the end of the semester. Although some ideas (and all raw data) were common to the reports, the students did not CHEMICAL ENGINEERING EDUCATION

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work together on equipment design. They were allowed to discuss their ideas on data require ments and the overall process flow sheet. When it was agreed that all the essential data were avail able, each student worked independently. Both the Jab and the design courses culmi n ated in a seminar presented jointly to representatives from DuPont and to the Vanderbilt ChE faculty and students. Class representatives spoke for five minutes each on aspects of the laboratory or plant design; the talks were arranged so that the presentation would proceed smoothly and logically from problem statement and organization through experimentation and design to economic evalua tion and optimization. The formal presentation was fol lowed by an informal luncheon discussion between the student participants and their industrial advisors. EVA L UAT I ON THE JOINT PROJECT WAS successful from the standpoints of students, industry, and faculty. The two courses complimented each other appropriately, and all of our objectives were met, at least to some degree The students were able to see the results of a finished piece of work. They did well; they performed in a mature, professional fashion. They demonstrated a strong sense of ac complishment and pride after their oral presen tation to industry. Our goals were accomplished with a minimum of artificial rules, imitation engineering or pressure and guidance from the faculty. There were problems: Students from one group had a difficult time fully under standing what was being done in the other groups, or occasio n ally even by a different member of t h eir own group. In order to gather data as rapidly as possible, specialization was the order of the day For instance, one student would analyze samples for a month while another group would run the reactor While this may be efficient it is not a desirable situation since the man analyzing the samples would not have a good feel for the kinetics. Although our industrial consultants were always ready to help, the students failed to take full advantage of the situation; student industry interaction could have been better. The weekly reports were often poor; insufficient feed back was provided. F UTU RE P L AN S THE INTEGRATION OF plant design and laboratory was so successful that we see no reason to return to our old system. We are working on a new project for next year, again involving local industry. This time, we will arrange for the student groups to visit WINTER 1975 The two courses complimented each other appropriately, and all of our objectives were met, at least to some degree. the plant regularly and discuss their problems with the practicing engineers and scientists. The final report will be presented at the plant site. Financial support from industry seems in the offing. RE QUIREMEN T S F O R SUCC E SS WE ENTHUSIASTICALLY recommend the joint lab design approach. If you try it, you might consider four points which we feel to be of paramount importance : The cooperation of an accessible industry is essential. The company should be willing to help provide ideas, materials, and (within proprietary limits) information, A suitable problem must be chosen. If it is too old, all the necessary information will be readily available in the literature. If it is too new, it may be too "secret." A great deal of advance planning is necessary. The faculty members in charge must familiarize themselves with the process and with its problems. They must de velop a feel for the feasibility of the assignment Consider your equipment constraints in advance The project is unlikely to succeed if the students have to wait for orders, shipments, and deliveries. A CKNOW L EDGMEN TS THE COOPERATION OF E. I. duPont deN~mours and Co., Old Hickory, Tennessee, is gratefully acknowledged, particularly the help of Mr. A. B. Alexander and Miss Martha Andrews. Joint efforts of this sort make a real contribution to the future of the profession. Much of the equipment used in this project was provided by the Olin Foundation. RE F ERENCES 1. Pen-y, R. H., and Chilton, C. H. (eds), Ch e mical Engineer's Handbook" ( 5 th Ed.), McGraw-Hill, 1973. 2. Peters, M. S and Timm e rhaus, K. D., "Plant Design and Economics for Chemical Engine e rs (2nd Ed.), McGraw-Hill, 1968. 3 Tomita, K., and Ida, H., P o l y m er, 1 4 5 5 (197 3 ). 4. Tomita, K., Polym e r, 14, 5 0 (197 3 ). 5. U.S Patent 3,174,830 by A. Watzl et a l (to Vereinigte Glanzstaff-Fabrik e n A. G.) (March 2 3 1965) 6. Baker, T. S., Fisher, G. T., and Roth, J. A J. ChE Dctta, 9 1 11 (1964). "'-" 21

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PRELIMINARY APPRAISAL OF A SELF-PACED LABORATORY HOW ARD F. RASE University of Texas Austin, Texas 78712 THE SELF-PACED CONCEPT in education has received the greatest attention in standard courses which have traditionally been taught by the lecture method. In the co ntinuing debate on the value of the self-paced approach the most convincing disadvantages cited are the lack of regular instructor contact and of group interaction Although these deficiencies ca n theoretically be eliminated, they seldom are be cause the system inherently operates more smooth ly, but not necessarily for the student's good, when such aspects are minimized It has been in teresting, therefore, to discover that a self-paced laboratory can combine the advantages of self paced instruction without the major disadvant ages, while at the same time making the labora tory an interesting and challenging experience. THE TRADITIONAL ChE LAB THE TRADITIONAL LABORATORY in chemical engineering usually involves a number of set experiments which are repeated each semester. These normally include experi ments in unit operations and other areas such as reaction kinetics. In many cases the laboratory has been made more interesting by adding special projects which are never assigned more than once and which are similar to technical service or de velopment problems soon to be encountered by the young engineer in industry. Invariably however, experiments and reporting periods are The results of this effort were astoundingly gratifying. The students worked enthusiastically, with a level of skill which indicated hours of planning and thought seldom found in an undergraduate lab 22 Howard F Rase is the W. A Cunn in aham Professor of Chemical Engineering at th e University of T exas. He was a process engineer with Foster Wheeler Corporation and Dow Chemical Company before joining th e faculty at Th e Uni ve rsit y of T exas at Austin i n 1952. H e has served as Chairman from 1963 1968. Hi s researches are in catalysis and process design in w hi ch areas he has written over fift y (50 ) articles and thre e books. scheduled so that the course is completed just be fore the final examination period as are typical lecture courses. There is no in cent i ve for working harder and s marte r in order to finish earlier. This aspect of the laboratory experience bears little resemblance to real -life si tuations where time pressures are often great and where indeed the profe ssional is self -p aced THE SELF PACED LAB WE DE C IDED TO ATTEMPT a self -pa ced laborato ry based on the premise that since the course requires a set num ber of experi ments and a major special project, students will find it mo re stimulating to be a llo wed to complete the course as rapid l y as possible. Students were as signed the required set experiments along with a special project at the beginning of the course. A special lectu re was given on organizing and exe cuting experiments, and methods for solving technical-service and development type problems Chem. Engr., page 66, Sept 8, 1969 CHEMICAL ENGINEERING EDUCATION

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TABLE 1 TYPICAL SET EXPERIMENTS 1. Batch reactor study of ethyl acetate spaonification 2. Batch distillation of selected binaries and scale-up 3. Operation of pilot-scale forced circulation evaporator 4. Study of major characteristics of fluidized beds 5. Operation of a tubular reactor characterized by the special projects were de scribed. Typical set experiments and special products used in the laboratory are summarized in Tables 1 and 2. TABLE 2 TYPICAL SPECIAL PROJECTS 1. Study of the mechanism of plugging in fixed beds 2. Osmotic drying of fruit 3. Optimum continuous production conditions for compression molding 4. Purification of biuret 5. Purification of glycerine still bottoms 6. Removal of 4 ppm of chlorinated hydrocarbons from air 7. Optimizing precoat and body-feed ratio of filteraid in the filtration of a viscous mixture of alkylene oxides It has been interesting to discover that a self pated lab can combine the advantages of self paced instruction Without the major disadvantages, while ... making the laboratory an interesting and challenging experience. RESULTS T HE RESULTS OF THIS effort were astound ing and gratifying. The students worked en thusiastically and with a level of skill which in dicated hours of planning and thought seldom ob served in an undergraduate laboratory. The healthy competition which was fostered by a general desire to finish at a suggested early time or earlier had several desirable side effects. It fostered a great deal of interest in all the projects on the part of each group su,l!h that students learned more and gained broader range conceptual insights on problem solving. Because of the high level of interest and the strong de sire to complete the work, both the professor and his teaching assistant were drawn into more frequent oneWINTER 1975 on-one tutorial opportunities. The students were much more strongly interested in probing meanings and methods. Innovation was much more prevalent in this atmosphere created by the time pressure. Students were not only innovative technically but also in their planning and time management. The common loss of time experienced in starting and stopping work soon prompted several groups to schedule longer but fewer work periods. Other groups found that two set experiments could be done at the same time when one required long periods to equilibriate. These highly desirable attributes seldom flower in the traditional laboratory. CONCLUSIONS A SELF-PACED SENIOR laboratory in chemical engineering has many advantages as a teaching tool for the development of competent professionals A successful course of this type re quires a great deal of planning by the professor, procurement officer, and departmental mechanic and electronic technician. Delays caused by the establishment itself can be damaging to the zeal of the young but eager learner. ChE Educator: FINLAYSON (Continued from page 3.) OUTSIDE INTERESTS L IKE MANY WHO come to live in the Pacific Northwest, Bruce and his family have grown to love the out-of-doors. He bicycles to work, rain or shine. Now that his children are old enough ( > '--' 5), he and his family of three children and one foster child have backpacked together in both the Cascade and Olympic mountains. In the winter all six members of the family take to skiing. Bruce has also continued his interest in music, though drums have given ground to the guitar. He and Pat also enjoy attending the Seattle Symphony concerts and plays, and for other relaxation Bruce will occasionally read a mystery In addition to his dedication to his family, re search, and teaching Bruce is an integral part of the Department and of the College of Engineer ing. He has been chairman of many committees and now represents the College on the Faculty Senate. All of us on the faculty are pleased and proud to have Bruce among us. The future holds great promise for him. 23

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REPORTING PRECISION OF EXPERIMENT AL DAT A KENNETH R. HALL Texas A & M University College Station, Texas 77843 DONALD J. KIRWAN and OTIS L. UPDIKE University of Virginia Charlottes vi lle, Virginia 22901 S IMPLE CONCEPTS OFTEN receive the com ment, "but everyone knows that!" Un fortunately, everyone seldom includes all persons. In particular, we feel this generalization applies to one of the basic responsibilities of the scientific community-reporting the precision of experi mental data. Many times in theses, dissertations and even in technical papers this straightforward, mathematically obvious exercise is either ignored or applied improperly. The concept of precision is precisely defined and is a statistical quantity not to be confused (though it frequently is) with the equally precise concept of accuracy. Precision is a measure of the experimental reproducibility, that is, of the random errors associated with the apparatus and operator. The accuracy is a measure of the abso lute quality of the data, that is, how closely the data approximate the true values of the ob servables. We can calculate precision by standard statistical techniques (and approximations), but we must estimate accuracy based upon knowledge of the apparatus, calibration against known standards, and confidence in its operation. The standard deviation is the preferred repre sentation of precision and is defined as the square root of the variance of the data. For example, if z is an observable, its variance is the expected value of the square of the deviation between the ob served qqantity and its expected value: var (z) = < (z < z > ) 2 > (1) Assume we are collecting data which meet the usually-satisfied continuity requirements allowing z -:< z > to be approximated by a Taylor series trurrcat~d to first order, z < z > "' i:: i ( ~ 2 ) (x. < x > ) o :K_L xi 1. 1. (2) 24 where the X; are the independent variables deter mining z. To obtain an estimate of the standard deviation, square ,:iach side of equation (2) : a z 2 (z < z > ) 2 l (--) (x. < x. > ) 1. a x. 1. 1. 1. X. 1. + 2 (~)(~)(x.< x. > )(x.< x. > ) a x a x. 1. l. l. 1. 1. l. l. J > l. (3) then take the expected value of the result (as suming the derivatives are exact) : 2 var(z) <=' l (~) var(x.) 1. ax X. 1. 1. l. (4) The standard deviation of z,
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variances of the xi are seldom available, but can be replaced with estimated errors of the X;, e2;. The equation for estimating the standard devia tion then becomes a -.:! (I z (~/ cl x. l X. l 2 ] 0 5 E: l (6) An attractive and valid geometric model for the additivity of variances results from consider ing z as uncertainly located in n-space, with the uncertainty arising from the errors in the n in dependent variables, which combine orthogonally if each independent variable acts along its own coordinate of the space. ( Correlations, in this model correspond to non-orthogonality of the error-component vectors.) Reviewing the assumptions involved in equa tion (6) : z can be approximated by a first-order Taylor expansion; errors in the independent variables, xi, are not correlated; variances of the independent variables may be approximated by their apparent experimental errors, Ej. (Along with the third assumption, we caution that there are occasional cases where badly skewed or bimodal error distributions make simple addition of the variances, or second mo ments, inadequate.) A common and less defensible technique for assigning precision to data is to use the deriva tives themselves as weighting factors. Assuming Z = Z(X1, X 2 .... ) dz = l: (~) l ci X. X. l l dx. l (7) dz is assumed to be az and the dx; are all replaced with E j. Of course, the partial derivatives and E; can be negative; so the absolute values are commonly used : tr' <'! l: I(~) E: I Z d X. l l l X. l (8) Equation (8) is often said to provide the "maxi mum error estimate." This statement has no valid theoretical basis ; a defensible worst-case error estimate would actually be 3az from equation (6). Furthermore, when absolute values are used, physical significance becomes obscure, and geo metrical significance is destroyed. Effectively, equation (8) contains all the assumptions of equa tion (6) plus one more-that the square root of a sum is the sum of the square roots. This latter assumption is not generally valid'V 4 +; + 16 = ~ 5.4 2+3 + 4 =9 Now consider some examples, the first involv ing the precision in measuring liquid composi tion by interferometry. Kirwan ( 1967) provides the difference between interface compos ition and that of the bulk liquid :,~ A 1 y = y y = __ o (___i!l_) ~ o sx; 2 t d y l (9) where ,0, N is the fringe shift at the interface, A 0 is the wavelength of the light, t is the thickness of the optical wedge and n is the refractive index. Kirwan also reports that the percentage errors in ,0, N, A 0 t and ( a n / aYh are respectively 20 % < 0.1, % 10 % and 5 % In this case (when all ob servables appear as multiples in the equation), it is convenient to divide both sides of equation ( 6) by the dependent variable: (10) Now percentage errors can be substituted direct ly, yielding ay/ Y = 0.23. From equation (8), the value would be a,./ Y = 0.35. A second example involves a PvT experiment For illustration, assume a van der Waals gas with the properties T c = 356 .37K, P c = 3.700 MPa, ci = 1.000 X 10 -s b = 1.000 X 10 4 and the gas Many times, in theses dissertations and even technical papers, this straightforward exercise (of reporting precision) is either ignored or applied improperly. WINTER 1975 25

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Otis L. Updike, Professor of Chemical and of B iomedical Engineer ing at the University of Virg in ia received the B Ch E from Virginia and the Ph D ( 19 44) from the University of Illinoi s; he also has held an NSF Science Faculty Fello wship at Ca lt ech. In industry, chiefly with Westvaco Chemical (now part of FMC) and Oak Ridge National Laboratory, he worked in process development, design, and systems process control. With inter ests, and system identification in both the process and the biomedical fields, he is a member of AIChE BmES ISA IEEE SCS, AAMI and ASEE. Kenneth R. Hall received his B S. from Tulsa University M S. from U of California at B erkeley and Ph.D. from the University of constant, R = 8.3143 X 10 -u MPa m "/ mol K. We desire t he precision in determining the volume at .360 82K and 100.0MPa. The following equation is applicable: P= JIT_ -~ v-b V Note that the observables do not appear as simple multiples, so an equation similar to equation (10) does not exis t. Using E T = O.0lK and et> = 0.01 MPa (both reasonable va lues for these measure ments), equation (6) estimates u, = 1.3 X 10 9, or 0 .0011 while equation (8) produces u,=1.7 X 10 u, on 0 0015 % These precisions are reasonable because the gas is in a low compressibility region. Our third example concerns measurement of oxygen concentration with the Westinghouse con centration cell sensor (Updike, Dammann, and Bowers, 1968). The response of this device is N ernstian, and may be described by the relation 6E = ..ll..ln ~ w_ nF t 02 (12) where 6 E is the ce ll output vo lt age; R and F are the gas constant and Faraday's constant; T is absolute temperature of the zirconia electrolyte; n is the number of e lectrons transferred in t he electrode reaction; and f is the fugacity of oxygen in reference and sample stream, as indicated by the subscripts Equation (14) can be rearranged conveniently, with substitutions for the fugacities, to the form / ~ ) (~) (e n;~E ) \ ref ~ r ef y6E/T = Yref a e 13) (13a) where P samp a nd P,. er are total pressures in the samp le and reference regions; sn mv and r er are 26 Oklahoma He held a NATO Post doctoral fellowship in Belg ium and had indus tr ial expe rienc e with Chemshare, In c. and Amoco Produc tion Research. He taught at the Universit y of V i rginia for a number of years and is currently on the Chemical Engineering Faculty at Texas A & M University. His primary resear c h interest is in the thermo dynamic properties of fluids Donald J. Kirwan received his B. S. degree from Illinois Institut e of Technology and th e M S and Ph.D degrees from the University of Delaware, all in Chemical Engineering He worked at the Mon santo Company in St. Louis for three yea rs prior to jo ining the faculty of the Universit y of Virginia His research interests are in the areas of mass transfer crystallization and enzyme engineering the corresponding fugacity c oefficients; and a, {3 and y are introduced for convenience as shown in form (13a) For the factors in e quation (13a), the un certainties are estimated as E .r = 0.001, E = 0.002, E /3 = 0 001, E A E 1' f Ll = 0.0001 V, and E-r = 3K (at 1123K). (The pressure and fugacity ratios are handled as single variables because errors in these terms are, by design compensating.) The expression for the estimated standard deviation results from differentiation of equation ( 13) and substitution in equation (6) ; the derivatives are conveniently developed from the concise form 13a). Substitu tion of these derivatives into equation (6) yields (14) Thus, at y 00 = 0.500, and 6 E = 0.0210 volts 0 r 5 7 c s y 02 = (5.7 + 1.0 + 0 3 + 4.J + l.3)x 10 j = 0 0035 This third example shows several points: (a) the exponential factor does not allow the simple combination of percentage errors which was possible in the first case; (b) the independent variables contribute unequally to the overall un certainty, and equation (6) displays clearly the minor contribution of uncertainties in f3 (the fugacity ratio); (c) w ith more error contributors, the ratio between the more defensible estimate of equation (6) and that of equa tion (8) has : in creased; ( d) expected c orrelations were handled by using ratios of variables in factors a and f3; and ( e) because of the exponential form the error level changes with y 02 and Yrer-arguing for care in the choice of the reference gas concentra tion when this sensor is used. (Continued on page 30 ) CHEMICAL ENGINEERING EPUCA'l'ION

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One of the best fire fighters in your town is a pa ir of pajamas Every town, big or small, needs experienced fire fighters The ones you see here in full battle gear belong to Engine Company No. 1 of Free port, New York. The fire fighter that looks out of place is the pair of paja mas on the child You see, by law all sleepwear up to size 6X must be made flame-retardant. And these pajamas are made of 100% Dynel modacrylic, a flame-retardant fiber created by Union Carbide. When exposed tofire,properly constructed fabric of Dynel does a very sensib l e thing It shrinks from it. And if a flame should reach it, it extinguishes itself as soon as the flame is removed. Dynel has a lot more going for it. It s soft, non-allergenic, durable, colorfast, moth proof So you're likely to find this versatile fiber in all sorts of things.Wigs, draperies, carpets, tents, paint rollers. But we doubt that there will ever be a better use for Dynel than helping protect young chil dren against a very old enemy. Fire : I Today, something we do will touch your life. An Equ a l Opportunity Employer

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SOME SIMPLE EXPERIMENTS FOR FIRST YEAR STUDENTS A.M.GERRARD T eesside Pol ytechnic Middlesbrough Cle ve land County, England F IRST YEAR STUDENTS of the Polytechnic's sandwich (co-operative) BSc in Chemical Engineering are taught transport phenomena [l, 2] and some elements of process design. This early introduction to Chemical Engineering fundamentals allows them to make a real c ontri bution when they join industry for four months of project work after c ompleting one academic year of study. This situation has led to the de velopment of some simple experiments to suggest to the embryo engineer that some parallels do exist between the, at first, apparently dissimilar processes of heat, mass and momentum transfer. These experiments are carried out in the first few weeks of the term, often before the subjects are handled formally in class. The common link we chose was the simple first order differential equation: = k y (1) dx indeed all the three systems to be studied can be modelled by this equation CAPILLARY FLOW In the first experiment, the rate of drainage of a Newtonian fluid through a capillary is measured against time. The vertical reservoir is filled with water, say, and allowed to drain, the height of the interface being measured at given time intervals. A mass balance over the system coupled with hydrodynamic considerations yields the well known expression : dH = Kt dt 11 d 4 pg where K lZS A Integration then gives: ( 2) H = Ho exp (Kt) (3) which is the required model of the system. To obtain the previous expressions the student must know the Hagen-Poiseuille equation and TABLE 1 SUMMARY OF EXPERIMENTS Experiment Subject Method of Modelling Underlying Theory Extension of basic experiment Handling of Results 28 Drainage through Capillary Momentum transfer Transient mass balance and steady state force balance Laminar flow Allowance for entry effects Cooling of Glycerol Heat transfer Transient heat balance Natural convection Allowance for variation in heat transfer coefficient Use of Jog-linear graph paper, normalized plots and curve s ketching from the basic model. Treat results using regression analysis. Dissolution of benzoic acid Mass transfer Transient mass balance Whitman's film theory Effect of agitator spee d on mass transfer CHEMICAL ENGINEERING EDUCATION

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ii\ ( A [) H e f( -4, d 1 ,,.. .R., 'FIGURE 1 F l ow through a capillary hence have an understanding of laminar flow to gether with the definitions and use of viscosity, shear stress and strain in order that the equation can be derived. As soon as the model has been formulated the student is asked to sketch the H t curve, noting that it will tend to an asymptote as t oo It is also worthwhile demonstrating that the curve has no maximum or minimum by the classical calculus approach. These points are genera ll y brought out in an extended 'viva' during the laboratory session. The students, working in pairs, have already produced a short planning re port prior to their carrying out the experiment; this ensures that they are well prepared for the cross-examination which follows! As soon as the experiment is concluded, the results can be compared with the theoretical pre dictions. Thus, the predicted and experimentally determined values of K can be computed, the latter being facilitated by the use of semi-log paper. Then a discussion of errors can be made, indeed the log (H / Ho) against t curve can be cal culated using regression analysis [3], the more able student can also introduce here the idea of entry effects and attempt to make some allowance for them. If 'the essence of science is prediction' then this experiment is a fine example. DISSOLUTION T HE NEXT EXPERIMENT introduces some simple ideas in mass transfer. A cylinder of some sparingly soluble solid is dissolved in an ap propriate fluid in a stirred flask. (We use benzoic acid in water, the solution being samp l ed at regular intervals, say 5cc every 15 minutes, and titrated against 0.01 N caustic soda). Some familiarity with Whitman's theory of interphase mass transfer is needed prior to the modelling of WINTER 1975 the system. Many student's first attempt at this involves defining the system over which the tran sient mass balance is to be carried out as the solid benzoic acid plus the water-this approach does not allow much progress to be made hence -::!m phasizing the care needed in choosing control volumes! The simplest differential model is, of course : V dC = K A ( C -' C) dt 1, s ( 4 ) its integration being straight forward, again semi logarithmic paper allows a straight line representation of the experimental data. The dis cussion of errors centres around the importance of the area of the cylinder and the solution volume changing slightly throughout the proceedings, A useful-and often neglected-check on the titra tions is the measurement of the overall weight loss of the benzoic acid block. As before, the basic experiment can be extended, this time by investi gating the influence of agitator speed N on the mass transfer coefficient, Kr where : 0 6 u. N" (5 ) to demonstrate this conveniently the student is introduced to the use of log-log paper, perhaps for the first time. COOLING T HIS TRIO OF EXPERIMENTS is e ompleted with a study of heat transfer. A lagged beak er full of a hot non-volatile liquid, glycerol say, is Mr Gerrard graduated in Chemical Engin e ering from Edinburgh University and then worked in the Research and Development D e partment of Cadbury-Schweppes Since joining his present post his technical interests have i ncluded particulate t e chnology process e conomics and optimisation togeth e r with the development of the undergraduate laboratories 29

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allowed to cool in a draught proof perspex case, the principal mode of heat loss being natural con vection. The temperature of the fluid and the sur roundings are noted for an hour or two. Again a transient (heat) balance yields the desired model: -Mcp d 0 = hA ( ll 0 a) (6) dt whose integrated form can be represented by a straight line on log-linear graph paper. An exten sion of the basic theory which allows for the de pendence of heat transfer coefficient with temperature difference where: 0 25 h a ( 0 0 a) can also be made. (7) All of the experiments can be repeated using different initial heights, concentrations and temperatures respectively. The results then for, say, all the fluid flow experiments lie on the same line if the normalized ordinate (H / Ho) is used. Indeed if the normalized abscissa (Kt) is also used -;; hen the results from different diameter capillary experiments also can be reduced to a one line representation. This dimensionless plotting is yet another important concept for the student to grasp. CONCLUSION WE HA VE FOUND THAT these three inexpensive and simple experiments have aided our student's comprehension of, and belief in, the analogous behaviour of the various forms of trans port phenomena. Equally importantly, the writing of full engineering reports on their :findings pro vides useful training prior to their early in dustrial baptism Perhaps as a postscript we can also mention two further experiments which are given to our first year men which again are governed by : dy ky dx (8) these being the transient mass balance over a stirred tank containing acid diluted with water and a rig on the rates of batch sieving. ACKNOWLEDGMENT The author is happy to acknowledge the help ful comments of his colleague C.J. Liddle in the development of the experiments described ab ove. NOTATION A Area C 6 C (Saturation), concentration Cp Sp ec ific heat 30 d g H 0 H h Capillary diameter Acceleration due to gravity (Original), h eig ht Heat transfer coefficient Constants K, k Kr, Mass trans fer coefficient l ength of cap illar y I M N t V Mass Rotational speed Time Volume 0n, 0i, 0 p (Ambient, initial), temperature Density Viscosity REFERENCES 1. Bird R. B., Steward W. E., Lightfoot E. N., "Trans port Phenomena," J. Wiley, 1960. 2. Welty J. R., Wicks E. C., Wilson R. E., "Fu nda mentals of Momentum, Heat and Mass Transfer," J. Wiley, 1969. 3 Chemical Engine er ing Laboratory Manual, Teesside Polyt ec hni c, September 1973. PRECISION: Hall et al. (Continued from page 26.) Equation (8) approximates CT z as greater than the more valid estimate of equation (6). The difference depends on the number of error-con tributing independent variables and on the deriva tive-weighted co ntributions of each. For the common case where three or four factors eac h contribute comparably to the overall variance, the linearly-additive equation (8) produces estimates not more than twice the orthogonally-additive estimate of equation (6) ; for only one major con tributor, results are essentially the same. Since the calculation required is only negligibly greater, the theoretically defensible equation ( 6) should always be used. We hasten to add that nothing new is present ed here. Equation (6) is available in many references, for exa mple Mickley, Sherwood and Reed ( 1957) ; but we :find that an overwhelming majority of students-and even co lleagues!use 2quation ( 8) This co mmunication is an attempt to advocate the more rigorous, well documented, largely neglected approach. REFERENCES Kirwan, D. J., "Crystallization Kinetics of Pure and Binary M e lts," Ph.D. Dissertation, University of Delaware (1967). Mickley, H.S., T .K. Sherwood, : md C.E. Reed, "Applied Mathematics in Chemica l Engineering," 2nd e d., Mc Graw-Hill ( 19 5 7). Updike, O.L., J.F., Dammann, and D.L. Bowers, "Per formance of a Fast-Response Respiratory Oxygen Sensor," .Proc. Rocky Mtn. Bioenr;. Sympos. (Denver, 1968), 109-116. CHEMICAL ENGINEERING EDUCATION

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[j;jI news In Memorium JACOB JORNE Wayne State University D e t roit, Michigan 48202 W ITH THE SUDDEN DEATH of Professor Julius L. Jackson on July 5, 1974 the scientific community lost a productive, stimulating and wonderful colleague. Dr. Jackson was buried in the special memorial plot at the Weitzmann In stitute of Sciences, Rehovot, Israel, where he was a visiting scientist for the summer. Dr. Jackson served from 1969 to 1974 as the Chairman of the Department of Chemical Engineering and Material Sciences, Wayne State University, a post he resigned this June in order to devote more time to teaching and research. He recently served as a member of the Publications Board of CEE He is survived by his wife, three sons and a daughter. Professor Jackson was born on 9 November, 1924, in New York City and received degrees in Physics at Brooklyn College, Princeton, and New York University, where he earned his Ph.D. in 1950. He served as a visiting professor at the State University of Iowa prior to joining the Applied Physics Laboratory of the John Hopkins University as a research physicist in 1951. He also served at the Office of Naval Research and in 1956 he became a research physicist at the Nation al Bureau of Standards where he worked in the Free Radicals Program and in the Statistical Physics Section. In 1961 he joined Howard Uni versity as Professor of Physics. WINTER 1975 A memorial Festschrift is being prepared, a memorial lecture series will be held at Wayne State University, and a fund for the education of his chi ldren has been established. Contributions to any of these should be sent to Julius Jackson Memorial Fund, Wayne Fund, Detroit, Michi gan 48202. Jacob J orne, Wayne State University, Detroit, Mich. [i) ;j a book reviews Polym er M citerials Science, by Jerold M. Schultz, Prentice-Hall, Inc., Englewood Cliffs, N. J. 1974. Reviewed by A T. DiBenedetto, U. of Connecticut; Storrs, Conn. p OLYMER MATERIALS SCIENCE is a textbook for senior level or first year graduate students majoring in chemical engineering, physics or materials science. It presupposes a good background in physical chemistry, crystal lography solid mechanics and mathematics. The text is divided into three sections. The first four chapters cover the science of polymer crystals in a rather unique way, emphasizing the experi mental techniques of characterizing polymer crystals and the interpretation of such measure ments. The second section is a very brief two chapters on polymerization and molecular weight distribution, included to describe the character of polymeric chains. The third section is a loosely connected set of five chapters on the properties of polymeric materials. Some of the material in these latter chapters are analytic descriptions of the relationships between structure and proper ties (e. g. rubber elasticity) while the rest is by necessity more qualitative (e. g. the mechanics of semi-crystalline polymers) Like most polymer texts that have been written in recent years, it reflects a point of view by the author of what should be in an introduc tory course in polymeric materials. Those who feel that st ud ents should be exposed first to the technology of polymers will not want to use this book as a text. There is no information here on plastics fabrication and end use. Those who feel that polymer synthesis and the control of proper ties through chemical reaction kinetics deserves at least equal time with structure-property rela tions, also will not want to use this book as a text. (Continued on page 48.) 31

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(i)n a classroom AN INTRODUCTORY DESIGN COURSE FOR ENGINEERING FRESHMEN GORDON R. YOUNGQUIST Clarkson College of T ec hnolog y Potsdam, New York 13676 INTRODU CING BEGINNING ENGINEERING students to the profession in a meaningful way has long been a problem. At Clarkson College of Technology a var iety of techniques have been tried, many meeting with a singu l ar lack of real success. The methods used have ranged from in formal orientation sessions to design to nothing at all. The long range effects of these attempts are difficult to measure, but one can be reasonably certain that the engineering profession loses a significant number of potentially productive mem bers when capable students are "turned off" by their first exposures to engineering in college. During the 1969-70 academic year, Clarkson's Engineering School faculty completed a major revision of its undergraduate curricula. These curricula provide for a common Freshman pro gram for all engineering students including a two course sequence (3 semester credits each) in engineering taught jointly by faculty from each department. The first of these, titled "Introduc tion to Engineering," is devoted primarily to de veloping skills in engineering graphics and digital computing as a means of solving engineering prob lems. Some orientation to engineering and its major branches is provided by lectures on topics related to engineering design, the engineering profession, or the relationship of engineering to society. The second course, titled "Introduction to Complex Design," is much more loosely structured than the first. Depending on the faculty involved the course has been conducted in a wide variety of ways but generally involving a design project of one sort or another. Typically, near the end of the first course engineering faculty members submit project descriptions to the students who are asked to indicate their preferences. Students are then assigned to sections for the second course, taking into account preferences and number limitations imposed by the nature of the project. 32 What follows will describe the methods that I used in teaching a section of "Introduction to Co mplex Design" each of the past two years. Centered about the design of a chemical plant, the course content and organization will be given in some detail and some measure of the students' response as well as my reactions to the course will be provided. Hopefully the information provided will be of some value to those teaching or planning a Freshman engineering course. COURSE OBJECTIVES J MUST CONFESS THAT I went into the course the first time with some trepidation. It never has been entirely clear to me just what such a Freshman engineering course should con sist of. Broadly, the engineering school agreed that the course should provide an introduction to the engineering profession through a design ex perience. However, no specific guidelines as to content or structure existed. Moreover, I had never taught Freshmen and therefore had relatively little insight into the kinds of problems they could handle. Gordon Youngquist rece ived his BS from the Uni ve rsity of Min nesota and his MS and PhD from the University of Illinois. Since 1962 he has been at Clarkson College of Technolog y where his teaching and research interests are in r eactor analysis, crystallization and porous media. CHEMICAL ENGINEERING EDUCATION

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I felt that the course should somehow intro duce the student to a variety of engineering ac tivities, hopefully in such a way as to motivate him to continue in engineering and to provide in sight into his future course of study and career. More specifically, the following objectives evolved:* 1. To provide experience at defining problems. Nearly all of the problems students do have been defined for them by someone else Consider typical textbook problems in science or engineering, for examp le. A student's candid response to some prob lems he was confronted with in this course: "How can I give an answer when I don't know what the question is?" 2. To provide some introduction to the various aspects of engineering design. Emphasis was placed on the distinction and inter relationships between process design and equipment design and also the important role of economics. 3. To provide experience at working with and for others on a long term ,roblem of broad scope. Most of the work that students have done at this point has been on short, well-defined problems that they have completed by themselves. They have had little experience at planning work on a long term problem which requires the joint efforts of several individuals. 4. To provide some experience at decision making. Few engineering problems have but one solution! 5. To provide a means of applying accumulated back ground to c ompletely new problems. 6. To provide experience at technical report presenta tion, both written and o ral. 7. To provide experience at evaluating the work of others. COURSE IMPLEMENTATION T O ACHIEVE THESE OBJECTIVES, I de cided to have the class do a chemical plant design using a format not unlike the one often used for our Senior design course. Table I pro vid~s general information about the staffing and structure of the course The first four weeks of the course were devoted to relatively short, in troductory problems The next eight weeks were spent on the design of a chemical plant. The final two weeks were devoted to evaluation of written design reports by the students themselves and to oral presentations by the students. The class met twice each week for two periods each day using two adjoining classrooms. These were standard classrooms with movable chairs, each accommo*Evolved is a mo st accurate description here. Some of these I had in mind before the course started. Others developed as the course progressed. WINTER 1975 dating about 50 students. In 1972, I had six and in 1973, eight teaching assistants working with me. The assistants, all undergraduate chemical engineers, were allowed 1 academic credit and Students w ho took the course had, early in their course of study, a broad range of experience and exposure to engineering that our typical student has never had in the past. given a very modest stipend for their participa tion in the course. The initial four week period served to orient the student's thinking toward the solution of eng ineering problems and to develop certa in prob lem solving skills that they would need later in the semester. Typically, the first half hour or 45 minutes of the class was devoted to lecture-dis cussion of a problem. During the remainder of the class period, the students divided into 5 or 6 man groups to pursue the problem further TABLE 1 STAFFING AND STRUCTURE Instructor: Assistants: Students: C lassroom s: Schedule: Overall format: G.R. Youngquist, Associate Professor of Chemica l Engineering. One undergraduate assistant for eac h 5 students. These were juniors or seniors in Chemical Engineering. All were Freshmen. In 1972, 34 s tudents and in 1973, 42 students, took the course. Of these about 2 / 3 were intending to be Chemical Engineers, a few were intending to be Civil or Mechanical Engineers, and the rest were undecided at this point. Used two adjoining standard classrooms. C l ass met two days per week, each day for two 50 minute class periods. The semester was fourteen weeks long, divided as follows: 4 weeks-Introductory problems cover ing some principles of material and energy balances. Some lectures, some group activity, some in dividual activity. 8 weeks-Plant design project by student groups of 5 to 6 cu lminating a written design report. 1 weekStudent evaluation of written de sign reports 1 weekOral presentations of designs; award made for best presenta tion. 33

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Clarksen's curricula has a two semester common freshman program taught jointly by faculty from each department ... the first is devoted to orientation to engineering, engineering graphics and digital computing ... the second involves a design project of some sort. through discussion and analysis. Three or four groups worked in each classroom to avoid con gestion. One assistant was assigned to each group to answer questions, to stimulate discussion if necessary; and to provide general guidance. I circulated from group to group to provide addi tional assistance. In some cases, this activity cul minated in a homework assignment to be sub mitted by individual students. The basic subject areas introduced during this time were only two : energy conservation and mass conservation. Generally I started with an ill-defined problem and worked towards a well defined problem which could be made quantitative. For example, on the first day of class I asked the students to "design a system which could be used to heat 10,000 gallons of a solvent from am bient temperature to l00 C." The problem state ment was made deliberately vague to cause them to ask a large number of questions, the answers to which would serve to define the problem. The students worked on the problem in groups, making up a list of such questions, and also de veloping a number of alternative ways that could be used. All of the groups considered batch-wise steam heating as an alternative, placing the sol vent in a tank with an internal heating coil. For the next class period, I restated the problem pro viding answers to many of the questions they had posed. We then looked at quantitative aspects of the problem, asking in particular how one might determine the required size of the steam coil. This led naturally to a discussion of the factors which influence the rate of heat transfer. The notions of the temperature driving force and the overall heat transfer coefficient were introduced. From these, we developed an unsteady state energy balance for the system making use of the defini tion of the derivative to arrive at an appropriate differential equation. Then, for a group activity I asked them to solve the differential equation and to calculate the required heat transfer area. Al though they had no prior exposure to differential equations, they quickly caught on to separation of variables and recognized how to solve the re34 suit either analytically or numerically. Following this, I introduced the log-mean temperature difference, albeit in the context of a batch system. Subsequently, I asked the students how the heat exchange system might be made continuous. Of course, they first suggested using the tank of the batch system with continuous flow. We discussed the merits of this suggestion and with a little bit of prodding they soon arrived at the concepts of double pipe and tube and shell exchangers. I brought a small tube and shell exchanger to class for their inspection. The students found this heat exchange problem very satisfying. Among other things, it was easy for them to visualize; they could use their intuitive skills readily; they saw how the mathematics they were studying could be applied to a practical problem; and it revealed the broad implications of batch versus continuous systems. Above all, they got some feel for the im portance of defining a problem and using what they already know to solve a problem they had never seen before. From here, we went on to look at a couple of elementary mass balance problems involving chemical reactions, then to combined mass and energy balances (adiabatic flame temperatures, e g.), ending the four week period with a qualita tive discussion of rates of chemical reactions and the characteristics of various types of chemical reactors. At times when they were struggling with the definition of a problem, the students were quite frustrated. In this respect, I tried to emphasize strongly that adequately defining a problem often is the most difficult part of finding a solution. I was continually amazed at the students' ability to use intuitive reasoning-much better than seniors, I often felt. They were adept at generating sound ideas, both for processes and equipment, and were especially sensitive to the economic implications of their ideas. The latter I found especially pleasing, the importance of money in design arose quite spontaneously throughout. CHEMICAL ENGINEERING EDUCATION

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ON TO PLANT DESIGN THE NEXT EIGHT WEEKS of the semester were devoted to the design of a chemical plant At the beginning of this period, I asked the class to divide themselves into 5 or 6 man engineering "companies," each selecting their own chief engineer. One teaching assistant was assigned permanently to each company as a technical consultant. Half of the companies, each doing its own design, designed a plant for the wet oxidation of sludge from a waste treatment plant while the other half designed a plant for convert ing the sludge to oil. Table 2 shows the letter which was used as the problem assignment. These two processes were selected because of their obvious relevance, because a reasonable amount of background information was available, and be cause the problems w ere sufficiently broad in scope that the interests of potential Civil and Mechanical as well as Chemical Engineers could be served Furthermore, I have some related reTABLE 2 DESIGN PROBLEM STATEMENT Integral Chemical Company 209 Peyton Hall Potsdam, New York 13676 February 6. 1973 --------~,onsultants, Inc. 342 Snell Hall Potsdam, New York 13676 Gentlemen: Our chemical proce ss ing facility in Potsdam has a waste treatment plant which produces 300,000 gallons of effluent per day. The effluent is about 3 % by weight solids (the rest is water) and the solids are 75 % organic. The composition of the organic material can be represented by the empirical formula C 11 8 H 1 70 0 51 N 17 P. A t present we are dewatering the effluent by vacuum filtration to 25 % solids and the solids are incinerated using fuel oil as an auxiliary fuel. The residual ash is landfilled. This proces s costs us about $20 per ton of dry solids. The filtration step has been no end of trouble to us however, since to be efficient incineration requires rather clo se regulation of the water content and our filters have tieen difficult to control. In addition, both the State and Federal Environmental Protection Agencies are putting pressure on us to reduce both particulate and chemical emissions from our incinerator stac ks. As a result we have been looking for alternatives to incineration for disposal of our wastes. Two such method s which have come to our attention recently and which appear potentially attractive for our purpose s are: 1) wet oxidation (i.e., the Zimpro proces s) and 2) conversion of the wastes to oil. Some of the possible advantage s we see for these proces ses are the following In the wet oxidation proces s, WINTER 1975 the organics may be more or less completely oxidized to carbon dioxide and water in the presence of liquid water and air. With liquid water present fly ash is no problem and many of the oxidation products will form water s oluble salts. Filtration of the effluent possibly may be unnecessary. Also, it might be possible to generate elec trical power by expanding the high pressure, high temperature gases which result from the process through a turbine. In conversion to oil, the organics are reacted in the presence of carbon monoxide and liquid water to produce fuel oil. This oil may be especially valuable to us in light o f rei : ent shortages. As with the wet oxidation process the emissions problems attendant to incineration should be largely checked. On the negati ve side, with either of these processes we will still have to meet the local pollution standards for both our off gases and our waste water. The residual insoluble solids will likely have to be s eparated and land filled. In addition, s ince both processes require moderate reactor pressure s and temperature s, capital costs for plant installation may be high. Since these processes do look reasonably attractive to u s, we would like your firm to do a plant design for one of them. This design should provide us with the basis for determinin g the advisability of proceeding to the final design and con s truction stage. As a minimum it sho uld include reasonably complete process and equipment speci fications along with your best estimates of capital and operating costs. We require that your final design report be submitted to us by April 19, 1973. You should also be prepared to make an oral presentation to our staff on May 1 1973. Very truly yours I. N. Tegral, President search interests and the two processes are quite similar so I would not spread myself too thin in terms of background. At the outset, I provided each of the groups with a few pertinent papers about each process. Each group organized its activities as it saw fit. I asked for very brief week ly activity reports from each company and two progress reports in addition to a final written design report, but beyond this imposed no specific structure No formal lectures were given during the project period. I did expect the students to s how up for each scheduled class, so that they The course should provide an introduction to the engineering profession through a design experience and motivate the student to continue in engineering and to provide insight into his future course of study and career 35

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could consult with the assistants, myself and each other Most of the companies stumbled around for two to three weeks trying to get themselves organized effectively and, subsequently, trying to define the problem. I did not interfere with this, except to make suggestions when asked. It took the students a while to recognize the value of a process flowsheet, but once this was done they were off and running. To assist the companies in getting started with the necessary material and energy balance calculations, I made up two lec tures on cassette tapes. This proved quite effective. In addition, I regularly brought to class references such as Perry's Handbook, Popper's Handbook for Cost Estimation, Handbook of Chemistry and Physics, and Peters and Timmerhaus Plant De sign and Economics. Especially towards the end of the project, these were used heavily. The stu dents often had considerable difficulty in using library sources, primarily because most of the potentially useful texts were written in language that was too advanced The companies organized themselves in a variety of ways, but I am certain that all came away from the design project with a good ap preciation of the difficulties of working with and for people in a situation where crossflow of in formation is vital. In most cases, the company engineers became "experts" in different aspects of the process, sharing their knowledge in disT he competitive spirit which pervaded during t h is time was tremendous .. companies went a l l out to make good presentations S t udents were able to ask penetrating ques t ions and discussions following were very spirited. cussions both in and out of class. The assistants were quite effective in working with the companies, developing good rapport with their groups As in the first four weeks, I circulated from comp~n;v to company during~lass meetings providing guidance wherever it was most needed. At the start of the design project, most of the students were a bit overwhelmed, feeling that a plant design was more than they could handle. By the end, most were surprised and pleased at how far they had progressed. ( Frankly, so was I ) Their final written reports were sub mitted on time, were remarkably complete, and 36 generally of high quality. The reports reflected some technical naivete, as you might expect, but I felt showed considerable imagination and creativity in treating some genuinely complex engineering problems. FI N A L REPOR TS Q N THE DAY THAT the final reports were submitted, I asked each student to evaluate the members of his company, without identifying himself An evaluation form was provided for this purpose. Many of the students commented later that they did not like this peer evaluation, but I felt that they responded conscientiously. At this same time, I also requested a course evalua tion by written response to four questions. The results were very interesting and will be present G d later. In class during the week following submission of the final reports, each company read and evaluated the written reports of two other companies Identifying features of the reports were removed so that the companies did not know whose report they were evaluating. The students took this seriously and did a good job of construc tive criticism I believe they found this activity very revealing, for it demonstrated the importance of good written communication and also gave them the opportunity to see in detail what ap proaches other students took in solving the design problems. The final week was devoted to presentation of oral reports on their design work. Four judges (a faculty member, a graduate student, a senior, and a freshman not involved with this section of the course) were asked to evaluate the presenta tion and an award was made for the best report. The competitive spirit which pervaded during this time was tremendous, and the companies went all out to make good presentations. Because they all had worked on substantially the same design problem, the students were able to ask penetrating questions and the discussions which followed each presentation were very spirited. For the most part, I tried to play down the importance of grades in the course. No examina tions were given. A few homework assignments at the beginning of the course were collected and graded, but these were not considered at all in determining final grades. Final written reports and oral reports were given a letter grade, but these were considered as collective grades for the C HEMICAL ENGINEERING EDUCATION

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company. To determine grades for individuaJs, I relied on 1) the peer evaluation mentioned above, 2) evaluations by the assistants, and 3) my personal evaluations as they developed over the semester Generally I looked for such qualities as leadership, creativity analytical ability, re liability, cooperation and effort by the students. Since both the assistants and I worked closely Students found their design project challenging and realistic engineering ... they liked the re l a ti vely flex i ble and informal organization of the course. They discovered engineering can be a lot of wo r k and that information gathering is a significant part of that work. with the students, it was relatively easy to deter mine which students knew the various aspects of the problems, which were leaders, and so on. The three evaluations cited above were remarkably consistent, and I have full confidence that the grades assigned were fair and justified. Con sidering the nature of the course, a pass-fail grading system may have been more appropriate. COURSE EVAL U ATIO N E VALUATING A COURSE is never very easy. The standard evaluation forms that one often uses for lecture courses are inappropriate for a course of this type, so I decided to ask the students for written responses to four questions. These were: 1) What aspects of the course did you like the best? 2) What aspects of the course did you like the least? 3) What are your chief criticisms of the course? Do you have any suggestions for improving it? 4) Has the course encouraged you to continue in engineering or discouraged you from doing so? Why? The students responded conscientiously with some very candid, meaningful, and interesting comments. These are too lengthy to reproduce here, but interested readers may obtain copies typed exactly as they were written by contacting the author directly. Table 3 briefly summarizes the responses. It is clear that the students found their design project to be challenging and realistic engineering from their vantage point and that they liked the relatively flexible and informal organization of the course. They discovered that WINTER 1975 TABLE 3 SUMMARY OF COURSE EVALUATION No. of responses 1972 1973 What aspects of the course did you like t h e best? 1. Work on a realistic engineering problem; opportunity to see the work of an e ngineer. 2. Work in small groups; learning how to work with others 3. Informal class organization; flexible scheduling of work; freedom to work independently. 4. Challenging, relevant, different. interesting design problem. W h at aspects of the course did you Ji ke the least? 1. Materials or information ha r d to find, or interpret; design problem too sophisticated. 2. De sig n problem too much work; work not shared equally by company members 3. Course organization; location; sc heduling 4. Difficulty in getting started on design problem. What are your chief criticisms of the course? Any suggestions for improving it? 9 9 9 10 8 3 10 3 1. Give a better idea of what is expected 5 ear ly; provide more information immediately. 2. Provide mor e reference material s 6 written at our level; give additional lectures; better assistants. 3. Do s horter project, simpler project. 5 4. Arrange field trips. 2 5. Make scheduling more flexible ; do not 3 r eq uire class meeting s. Has the course encouraged you to continue in engineeri n g or discouraged you from doing s o? Why? 1. Encouraged me. 22 2. Discouraged :m e. 4 3 Neither 4 13 8 14 10 10 10 6 5 8 9 3 5 2 30 1 8 engineering can be a lot of work and that infor mation gathering is a significant portion of that work. Many suggested that I provide more infor mation through additional lectures and materials but this seems directly related to inexperience at defining problems and organizing work effort. Others suggested that the design problem was too advanced for their background, but judging from what they were able to achieve I do not feel that this was the case. Significantly, only a small 37

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fraction (5 of 69) indicated that the course had discouraged them from continuing in engineering. Some of these made comments like "Now that I have seen what engineering may be like, I have decided it is not for me." On the whole, I feel that the course was highly successful. The course was exciting and challeng ing to teach and I enjoyed it immensely. The response of students was quite gratifying. It seems clear that much of what I tried to build into the course met with reasonable success. Whether any long term benefits will accrue remains to be seen. Certainly the students who took the course have had very early in their course of study a broad range of experience and exposure to en gineering that our typical student has never had in the past. Several of the assistants commented that they wished they had had such a course as freshmen, indicating that it would have given them much insight into their subsequent courses. At the beginning of the semester, at least the first time I taught it, the course consumed a great deal of my time. This was due partly to my in experience with the course, but partly due to the fact that all of the planning and course developCACHE COMPUTER PROBLEMS ment had to be done by the instructor. I found no suitable text to use as a guide or to provide problems. (The course just might be pretty sterile if there were!) Moreover, the course needs to be very flexible if it is to respond to the needs and interests of the students. Towards the end of the semester, especially as the design projects got well under way, little time was required beyond that spent in class Teaching the course the second time was much easier. I made some minor modi fications, but used essentially the same material and format as the previous year. This, plus the fact that I then knew how the students would react, reduced my time commitment to a mini mum. Provided assistants are available, I believe that the course could be run in this fashion with as many as 50 students p~r section. For group projects, there should be no more than 6 students per group. However, as the class size increases one does risk destroying the informal and personal atmosphere of the course. This could defeat the purposes of the course. Also, larger class size probably would mean a greater diversity of interests among the students. This makes it more difficult to select projects consistent with their interests. In any case, the instructor should limit the spectrum of design problems going simul taneously in the course to avoid spreading himself too thin in terms of his own interests and background. O $50 PRIZE FOR EACH PUBLISHED PROBLEM CHEMICAL ENGINEERING EDUCATION, in cooperation with the CACHE (Computer Aides to Chemical Engineering) Corporation, is initiating the publication of proven computer-based homework problems as a regular feature of this journal. 38 Problems submitted for publication should be documented according to the published "Standards for CACHE Computer Programs" (September 1971). That document is available now through the CACHE representative in your department or from the CACHE Computer Problems Editor Because of space limitations, problems should normally be limited to twelve pages total; either typed double-spaced or actual computer listings. A problem exceeding this I imit will be considered. For such a problem the article will have to be extracted from the complete problem description The procedure to distribute the total documentation may involve distribution at the cost of reproduction by the author Before a problem is accepted for publication it will pass through the following review steps : l) Selection from among all the contributions of interesting problems by the CACHE Computer Problem Advisory Board 2) Documentation review (with revisions if necessary) to guarantee adherence to the Standards for CACHE Computer Programs" 3) Program testing by running it on a minimum of three different computer systems. Problems should be submitted to: Dr. Gary Powers Carnegie-Mellon University Pittsburgh, Penn 15213 CHEMICAL ENGINEERING EDUCATION

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ChE Department: WATERLOO (Continued from page 7.) of the personality of the Waterloo department, some accomplishments and hobbies of the faculty are noted below: T. L. Batke, Ph.D. (Toronto) is a past vice-president of the University and was the first department chairman. He has recently been cross-appointed to the Philosophy De partment where he teaches a graduate course. L. E. Bodnar, Ph.D. (Master) is a past acting chairman, an outstanding amateur photographer and an authority on weaving. C. M. Burns, Ph.D. (Brooklyn Polytech. Inst.) has a wide range of interest in polymers and as editor for several years developed the CSChE Research Directory into an important survey of research activity in Canada J. J. Byerly Ph.D. (U.B.C.) is co-inventor of a patented process to control water pollution by certain metallic com pounds. K. S. Chang, Ph.D. (Northwestern) is a consistent ly highly-rated teacher and is an accomplished amateur magician, two attributes which prove valuable in his work on control theory. F A. Dullien, Ph.D. (U.B.C.) is an active consultant to industry; his work on porous media has found extensive applications. K. Enns, Ph.D. (Toronto) is co-inventor with John Byerley of the water pollution control process, and holder of a law degree. T. Z. Fahidy, Ph.D (Illinois) is an associate editor of Can. J. Chern. Eng. also manages to come up with a minimum of one joke per day. J. D. Ford, Ph. D. (Toronto) established our Unit Operations lab. C. E. Gall, Ph. D. (Minnesota) man ages to bridge the two cultures of applied math and theatre. He appeared in the Stratford Shakespearian festival for a season and has worked in a T.V. drama series (in a white lab coat!). A. H. Heatley, Ph.D. (Toronto) is semi -retired, but is still active enough to have purchased a small computer for his continuing work on numerical methods of solving differential equations. R. Y. M. Huang, Ph.D. (Toronto) works on polymers, has served as President of the University Faculty Association, and was the leading force in the University's annual Hagey Lectures which brings to the campus such figures as Fred Hoyle and George Wald for several days of dis cuss ion. R. R. Hudgins, Ph. D. (Princeton) is our current associate chairman (undergraduate studies) and, when not studying catalysis, plays the -harpsicord, organ or piano. I. F. Macdonald, Ph.D. (Wisconsin) has interests that range from blood to polymers. M. Moo-Young, Ph.D. (London) is the 1973 ERCO award winner for "distinguish ed contribution to ChE. in Canada," an associate editor of "Advances in Biochemical Engineering," an active con su ltant and, as a professional folksinger, has been record ed in live-concert on an album (Capitol-Dominion). G. S. Mueller, Ph.D. (Manchester) is a University Residence Tutor, coordinator of the Canadian Government-sponsored aid-program to the University of Havana, and plays his self-built organ. K. F. O'Driscoll, Ph. D. (Princeton) is our present chairman, co-inventor of a patented process for a soft-contact lens material; author of "Nature and Chemistry of High Polymers" (Reinhold), co -editor of Reviews in Macromolecular Chemistry, and has his own company, (Polymeric Enzymes, Inc.). D. C, T. Pei, Ph.D. WINTER 1975 (McGill) is a past associate chairman, and is cun-ently on sabbatical helping to establish a ChE curriculum in Singapore. E. Rhodes, Ph.D. (Manchester) is our current associate chairman (Graduate Studies), has developed a successful format for our annual depa1tmental visits by high-school students, is co-editor of a two-phase flow volume (Plenum). P. M. Reilly, P h.D. (London) is winner of a 1973 OCUF A "Outstanding Teacher" award. G. L. Rempel, Ph.D. (U.B.C.) is very active in putting Chemistry for all 800 first-year engineering students on a firm basis. C. W. Robinson Ph.D. (Berkeley is interested in PSI teaching methods and has prepared a PSI manual for mass transfer. J. M. Scharer, Ph.D. (Pennsylvania) has interests in microbiology and nature in general. D. S. Scott, Ph.D. (Illinois) is a past chairman, a past acting Dean, the 1972 president of C.S.Ch.E., a Centennial Medal winner, an active consultant, and co-editor of a two-phase flow volume. D. R. Spink, Ph.D. (Iowa State) has been a School Board member and still skates hard in the grad students hockey games. P. L. Silveston, Ph.D. (Munich) is an accomplished flyer and has his own consulting firm. G A. Turner, Ph.D. (Manchester) is author of "Heat and Concentration Waves" (Academic Press). B. M. E. van der Hoff, Ir. (Delft) is an associate editor of J. of Macro molecular Chemistry, who recently returned from a sabbatical in Nigeria where he established research and teaching in polymer Technology. J. R. Wynnyckyj, Ph.D. (Toronto) is an active consultant, is interested in the role of minority ethnic groups in Canada Location of University of Waterloo. UNIVERSITY AND LOCATION F OUNDED IN 1957, the University was the first of several new universities" in Canada. Today, it is co-educational and multi-faculty with both conventional and co-operative programs. The campus occupies 1,000 acres of landscaped grounds and is rated as one of Canada's most beautiful. The university is s ituated in the Regional Municipality of Waterloo. Because Waterloo city is part of the larger twin-city of Kitchener (overall population: 165,000) it is often not s hown on maps. Toronto is 60 miles to the northeast and Niagara Falls i s 80 miles to the southeast. The maps shows the spot! D 39

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BIOTECHNOLOGY An Old Solution To New Problems ELMER L. GADEN, JR. Columbia University, New Yo rk, NY 10027 INTRODUCTION MAN'S ESSENTIAL MATERIAL needs are commonly said to be "food, clothing, and shelter." In the parlance of an industrial civiliza tion a better statement might be (1) food, (2) energy resources, and ( 3) material resources. Food and energy resources can be considered to be consumed immediately if we ignore processing, transportation, and storage lags ; material re sources, are those which are converted into durable or semidurable goods. The needs of pre-industrial man were satis fied in large measure by renewable resources. Food supp lie s were completely renewable, al though somewhat uncertain. Although coal was known to the Romans, its use was limited before the 18th century; useful ene r gy was obtained mainly from water, wind, and wood Non-renew able resources were exploited substantially only in the fabrication of utensils, weapons, and struc tures, and even here recycling was significant. Many a European farm house and villa in corporates carefully chiseled stones from Roman walls and roads. One consequence of the industrial revolution was a rapid increase in dependence on non-renew able resources. Iron, and then steel, replaced wood in structures, machinery, vehicles, and ships; fossil fuels, coal, then oil and gas, became One consequence of the industrial revolution was a rapid increase in dependence on non-renewable resources. Iron, then steel replaced wood in structures, machinery, vehicles and ships; fossil fuels, coal then oil and gas became primary sources of energy. 40 .u 70 1----41----+-----l-l,--+-->,---+----"""I ... c 60 1-------i-+-----+--+----+---.+-------t .u i 50 1-------i----\c-----+---+--++----+----',----t H 40 1------i-----+---+---~ ... ,5 30 COL 1------i--+-+---+---+--'<---+------t FIGURE 1 the primary sources of energy The rapidity of this change i s evident from the familiar data of Figure 1 ( 1) indicating the energy sources em ployed in the United States since 1800. Technological man has dramatically increased this dependence on non-renewable resources. Over the last thirty years the seeming abundance of low-co s t petroleum and natural gas give birth to and sustained a burgeoning petrochemical in dustry Through it a significant component of our material as well as energy needs became de pendent o n hydrocarbons Synthetic polymers have replaced cellulosic substances, wood, paper, and cotton, in a host of applications while many industrial chemicals, once prepared from renew able raw materials, are now synthesi zed from petrochemical intermediates. Ethanol is the classic example. In 1939 about 85 % of the industrial (non-beverage) alcohol p r oduced in this country was manufactured by the fermentation, most of it from molasses and cereal grains. By 1960 ethylene had replaced these raw materials almost co mpletely. Par a llel with, and in part related to this shift CHEMICAL ENGINEERING EDUCATION

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At a point like this, one expects a clarion call for the development of new technology but I believe that much can be accomplished with technology already at hand .. also that biotechnology-deliberate exploitation of the potential for chemical change inherent in living cells-can contribute signficantly to this effort in our resource base we have witnessed a signifi cant and accelerating deterioration of the physical environment. The factors contributing to this decay have been discussed many times but one is directly related to the shift from wood to fossil fuels. This is a massive, environmental carbon imbalance Carbon, fixed by photosynthesis and subsequently converted to coal, oil, and gas over millions of years, is being rapidly returned to the atmosphere through the combustion of fossil fuels. We do not know whether the consequences of this imbalance will be as serious-even dangerousas some suggest but I would certain ly rest easier if carbon dioxide production were better balanced by c urrent photosynthetic activi ty (Figure 2). We are now confronted with several vital and interconnected problems arising from our great J ..., So l a r energy t l t CELLULOSE S UCROSE S T ARCH l >---> GLUCOSE --<. l J __ 7 V y ETHANO L PROTrN FU Y EL -< J L >FOOD T!:_e.::_ m.':_l ___ I I -_ ~1 = ?~12:-se n er gy '------r --~ e n ergy t THE ECO L OGICAL CARB U ,i BALANCE FIGURE 2 WINTER 1975 dependence on non-renewable resources: Petroleum and natural gas are in short supply and expensive. Availability may be increased for a time but the real cost will not decline. Furthermore, the en vironmental cost of substantially increased supplies may be catastrophic, e g. shale oil. Our agriculture has become intensive and productive but at great cost, especially in terms of energy from fossil fuels. The accumulation of waste s from this technological structure has reached staggering proportions, especial ly in and around urban center s. Traditional methods of disposal either consume large amounts of energy or are environmentally unacceptable. Most important, we now recognize that tech nological man has reached the point where his needs for food, energy, and durable goods are complex and interactive The choices which can be made in satisfying them are highly constrained and often competitive. This is illustrated, albeit in grossly simplified terms by the schemes pre sented in Figures 3 and 4. They summarize the various relationships, existant or potential, be tween the production of food proteins, energy for transportation and power generation, and petro chemicals. In fact Figures 2 and 3 should be one but such a presentation, even in the simple terms employed here, would be excessively complicated. I have therefore divided the total problem into those elements which are pertinent to food protein production (Figure 3) and those which provide energy for power and transportation and feed stocks for petrochemical manufacture (Figure 4). The significant points to be noted with respect to Figure 3 are : Cereal grains comprise the primary protein source for most of the world's population. Increased productivity can be achieved but only at the cost of relatively greater expenditures of fossil fuels, Heichel ( 2 ] has pointed out that modern agriculture derives practically all of its "cultural" (other than solar) energy from fossil fuels or other sources which replace labor Increases of IO to 50-fold in the cultural energy employed have only doubled or tripled the yield of digestible food energy. Major sources of protein for animal feeding are cereal grains, soy bean and fish meal. In addition, molasses, supplemented with nitrogen and phosphorus, has be come a popular component of livestock feeds during the 41

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L El L[Lo JS E-, F GLlCOSE "OLAS~1s-~--------r:-!1 ~ ar, 2.:!!~C'.r!11l FIGURE 3 Food Relationships past two decades. In 1946 less than one-third of the molasses consumed in the United States was used for livestock feeding. U. S. molasses consumption today is more than double that in 1946 and over 80% of it is used for liquid animal feeds. This escalation in demand, coupled with shortages of soybean and fish meal, has resulted in a three-fold increase in molasses prices over the last two years. Microbial protein is another potential contributor to both animal and human diets. Virtually all of the micro bial protein produced so far has been derived from molasses, primarily cane and beet. It is also technically possible to produce microbial protein from methane (very low yields) or methanol, from paraffins, and from ethanol. Commercial production from both alcohols has in fact, been announced [3, 4 ] Molasses was the dominant raw material for ethanol production prior to 1940. As we have seen, fermenta tion alcohol has subsequently been replaced almost completely by the ethylene based product. Waste or virgin cellulose offers another potential raw material for the production of either microbial pro tein or ethanol. With respect to Figure 4 it should be noted that: Electric power generation in the United States is cur rently dependent upon coal, natural gas, petroleum, and hydropower almost exclusively. Methanol is a potential fuel, either directly or following reconversion to me thane. Methane may also be produced by the anaerobic diges tion of cellulose and other solid wastes. Prolysis of such materials can also give oil and gas fractions said to be suitable as burner fuels. Transportation is almost totally dependent upon petroleum. Here we face a growing conflict between petrochemical needs and increased demands for aro matic components in gasoline to compensate for the reduction in performance occasioned by the elimination of lead Ethanol is another potential fuel for internal combus tion engines. As we have seen, it can be produced from a wide variety of saccharides including the glucose generated by cellulose hydrolysis, 42 No matter what time scale one accepts for the continued availability of our fossil fuel resources, it is apparent that we must redress the imbalance of recent decades and move toward a greater de pendence on renewable resources. This must be done in a manner which maximizes benefits by coupling material and energy generated in one sector as closely and efficiently as possible with material and energy needs elsewhere. Szego and Kemp [5] and Klass [6] have recently presented provacative analyses of the technical and economic aspects of renewable fuel resources. These proposals are based on direct combustion of wood ( Szego and Kemp) and anaerobic diges tion to methane (Klass) There is no question that such a trend will have immense social impact. It will therefore be necessary to achieve a finer degree of integrated technical, economic, and social projection and planning than we have ever achieved before. At a point like this one expects a clarion call for the development of new technology but I be lieve that much can be accomplished with tech nology already at hand. I also believe that bio technology-deliberate exploitation of the poten tial for chemical change inherent in living cells can contribute significantly to this effort. I pro pose to support these contentions by examining a specific proposal-the production of ethanol for use as an internal combustion engine fuel. I am not going to argue for this proposal-although it would be false for me not to confess an attraction for the prospect. Rather I want to use it to il lustrate the opportunities which have been creat ed by the sudden and, I believe permanent, rise in the real, relative c ost of petroleum. Before we look at this specific case, however, HlTHANE CMETH AN OL 1 CELWLOS naecob!c l dig e,ti on E -pyrolysis OIL/GAS FGLllCOSE ---i ST A RCH __J PETRO LEl ETll\1.ENE ~ETHANOL -E""'m, --GAS~L11;E 'M GAS O l LS -OlESEL FUEL Rf.DU CED C R UD E -FUEL O lL Primary :!!:_ I ~ lnt"el,.J 1 ?diate r;iw ma~erials ,_ FIGURE 4. Energ y Relationships > P OWER GENERATlOi'J ,-... CHEMIC A LS i TRA NSPOKTATlON CHEMICAL ENGINEERING EDUCATION _J

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a few points about biotechnology and its potential role in the utilization of renewable resources are in order. BIOTECHNOLOGY J HAVE ALREADY ALLUDED to the special role which I expect biotechnology to play in in creasing our dependence on renewable resources. Now I want to briefly outline the basis for that belief. Biote chnology can best be defined as the exploitation, under reasonably controlled condi tions, of the potential for chemical change in herent in biological systems. Importan t applica tions include ( 1) isolation, purification, and modi fication of bio logically active materials, (2) the use of individual enzymes and complete enzyme systems to effect chemical transformatio ns, and ( 3) the use of populations of who le cells for the same purpose (fermentation, biological waste treatment, etc.). As tools for generating chemical change, biological systems are powerful but often circum scribed [7]. They can catalyze a wide variety of chemical reactions, organic and inorganic, includ ing oxidation, reduction, hydrolysis, substitutions, group transfers, etc. [8] Products can be ob tained through both endel'gonic ( L', G= +) and exergonic ( L', G = -) reactions, thanks to the unique energy transfer and coupling mechanisms found in living cells. A considerable spectrum of raw materials is available for biological processes. In the realm of organic reactions these are referred to as "carbon sources." The traditional-and still the most wide ly used-carbon sources in biotechnology are the carbohydrates, especially starch and sugars. Re actions involving the exergonic degradation of sugars to products, alcohol production from glu cose for example, are common. In other cases the energy obtained from sugar oxidation is coupled to energy-demanding processes (endergonic) to permit biosynthesis of complex structures, cell protein for example. Recently hydrocarbons have become the focus of considerable interest as potential carbon sources for biotechnology. They supply much more energy per unit mass and yields of cell pro tein are correspondingly higher. On the other hand they introduce many problems for which satisfactory so lutions are available, but expensive. In addition, recent rises in the costs of hydro carbon raw materials have cast a pall over this whole matter. WINTER 1975 Cellulose is another carbon source of potential value Biological degradation of cellulose is an obvious and dominant feature of the natural wor ld. But it is also a painfully s lo w process in nature. Generations of biologists have sought organisms and conditions which will achieve more rapid degradation of cellulose but success has not come easily. The great advantage of the carbo hydrates-starch, cellulose, and the lower saccha rides derived from them-is, of course, their po tential renewability. Cultivation of carbohydrate producing plants represents the conversion-ad mittedly at low efficiency-of solar energy to available chemical energy. biotechnology is relatively simple. Inherent in the use of biological systems is the employment of only moderate temperatures and pressures Equipment is therefore relatively inexpensive and process plants are not so capital-intensive. Another aspect of biotechnology which has been overlooked is that it is relatively simp le. In herent in the use of biological systems is the em ployment of only moderate temperatures and pressures. Equipment is therefore relatively in expensive and process plants are not so capi tal intensive as are those employed in the petro c hemical area Another point which follows from these observations is that plants employing bio logical processes are less sensitive to scale -factor s. It is therefore possible to build several smaller units at a cost not much greater than one large unit. CHEMURGY AND BIOTECHNOLOGY THE CONTINUED AGRICULTURAL surpluses of the 1920's and 30's led to the de velopment of the "chemurgic" movement [9]. Che murgy included a number of specific pro posals whose general objectives were to channel farm surpluses into the chemical industry for con version to non-food products. Specific aims of the movement were : to discover new u ses for established farm crops to develop new crops for acreage producing sur plu ses of established crops to make use of agricultural residues and wastes from industries consuming agricultural materials 43

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Biotechnology was a key element in the overall chemurgic concept because biological processes offered some of the most promising avenues for utilizing agricultural materials One of these was the proposal to hydrolyze starch from cereal grains to glucose and then ferment the glucose to ethanol for use as a motor fuel. We will look at this more closely in the next section The great hopes of the chemurgic movement came to naught because: increased needs for food crops during and after World War II largely eliminated low-cost surpluses and led to a steady rise in the prices of commodity grains. rapid development of the petrochemical industry, based on low cost hydrocarbon feedstocks, offered direct com petition in many of the areas which seemed most at tract i ve for chemurgic development. The example of ethyl alcohol, cited earlier, is typical. Recently the chemurgic concept has been trotted out, dusted off, and presented anew [10] Its pitch has been changed, however. The raw materials of interests are no longer the cereal grains but rather the wastes and by-products generated by an industrialized agriculture and the society which it feeds. FUE L S FRO M C EL LULOSE C ELLULOSE, AS WOOD, is man's oldest fuel. It was not replaced by coal until the 19th century (Figure 1) and it is still the primary fuel for large segments of the world's population. The various natural woods exhibit somewhat higher heats of combustion that pure cellulose because of the oils and other materials which they contain but the differences are not significant. Wood is, of course, unsatisfactory for metallurgical ope rations because combustion temperatures are too low. It was therefore necessary, before coal be came available, to convert wood to charcoal. The great advantage offered by cellulose as a fuel is its renewability. This is the key to the pro posal by Szego and Kemp [5] for "energy planta tions Substantial use of cellulose as a fuel would permit a more favorable environmental carbon balance, as we have seen (Figure 2) Carbon dioxide returned to the atmosphere would be equivalent to that removed. On the other hand cellulose cannot be used as a fuel for one of tech no l ogical man's most prized possessions, the in ternal combustion engine. If renewable fuel re sources are to be seriously considered, effective means must be found to convert them to useful liquid or gaseous forms The various proposals which have been made for the employment of cellulose as a fuel fall into four main categories (Table 1). These are: direct combustion pyrolysis to combustible oil and gas fractions TABLE 1 Comparison Of Cellulose-Based Fuels Direct combustion of cellulose Pyrolysis to oil and gas fractions Anerobic digestion to methane Conversion to e thanol (Gasoline) Note s Heat of combustion 3.5 kcal/gm 12 4 kcal/ gm 7.1 kca l/ gm 11.2 11.3 kca l/ gm Energy efficiency < l 100 % 3 5 % (ll) 65 % ( 11 ) 50 % Limitations E x ternal combustion only: conventional burners. External combustion only : c onventional burn e rs. External combu s tion conventional/Internal combustion-high pressure storage Internal combustion: c onventional design. Pollution <" ) Particulate None Non e Hydrocarbons, SO X (a) Energy efficiency refers to the fraction of the energy available in th e ori g inal cellulos e whi c h is available in the final fuel. (b) Other than CO and CO 2 44 CHEMICAL ENGINEERING EDUCATION

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I am convinced that most current assessments of the future potential for various fuels is unrealistic because they are based upon estab l ished ratios between energy and other costs ... Ethanol is the only reasonable candidate fuel for internal combustion engines which can be derived from renewable resources. anaerobic digestion to methane conversion to ethanol Direct combustion of cellulose, usually in mix tures with other wastes, is already widespread. The use of wood wastes and shredded garbage in steam generating units are the most common examples Pyrolysis schemes are still largely in the development stage but methane from the di gestion of sludge and similar organic wastes has long been used as a fuel in waste treatment plants and sometimes in the surrounding c ommunity. The fourth possibility hydrolysis of c ellulose to ethanol, is the only one which offers a liquid compatible with contemporary internal combus tion engines Alcohols, methanol and ethanol al most exclusively, enjo y a long history of use as internal c ombustion engine fuels They were used experimentally in the early development of these engines when petroleum-based fuels were less readily available and have been widely employed when petroleum was in critical supply ( German y during the first World War ; Eastern Europe after it). ETHAN OL AS A MOTOR FUEL THERE IS ABUNDANT experience with ethanol as a motor fuel. It offers several ad vantages over, and suffers from some disadvant ages in comparison with, gasoline. The most ob vious disadvantage is its lower energy content (heating value) per unit weight (Table 1). This means that a larger volume and weight of fuel must be carried for the same vehicle range. Fuel lines, pump, etc., will also have to be larger to deliver the same fuel energy to the engine. Etha nol also exhibits a higher heat of vaporization which means that more heat must be supplied to the intake manifold of a carburetted engine This is usually waste heat from the engine however, and therefore represents no thermal penalty to the engine. On the other hand, ethanol has a high octane rating (RON = 106). It should therefore be possible to design an Otto cycle engine for alcohol with a higher compression ratio, and hence higher thermal efficiency than can be WINTER 1975 realized with gasoline. With the removal of lead, it has already become necessary to increase the aromatic content of gasoline in order to maintain current octane ratings This has placed an additional demand on already pre carious supplies of petrochemical feedstocks. Indeed, the question is widely asked whether we can afford to burn such precious commodities. Alcohol also offers substantial advantages over gasoline with respect to air pollution control. It contains no sulfur, leads to no unburned hydro carbon, and the lower engine temperatures involved reduce NO formation So far, alcohol has been used almost exclusive ly in engines which were designed for gasoline. The development of smaller higher compression engines for light-dut y personal vehicles, c om muter buses, smaller carriers, etc., is an especially attractive concept Such an engine could exploit the unique advantages of ethanol as a fuel and could find immediate application in captive market services-urban transit, delivery fleets, etc. POWER ALCOHOL ~~POWER ALCOHOL" HAS had a checkered record in ordinary times [12, 13] During the 20's and 30's many European countries either made the supplementation of gasoline with al cohol (10-15 % was t y pical) mandatory or pro vided tax incentives to encourage it These pro grams reflected both the general agricultural de pression affecting much of the w orld during this period and the a vailability of surplus alcohols from excess wine production, for example-in some countries. Although these alcohol-supplemented fuels were satisfactory in a technical sense, the overall programs were less so. It has been claimed [14] that the essential difficulty was the instability of alcohol s upplies. Since surpluses were the basis, the supply of alcohol for incorporation in fuel varied greatly and government regulations were changed frequently. This necessitated equally fre quent engine adjustments followed by increasing ly negative consumer reaction Willkie and Kolachov [14], in a provocative argument for an extensive, carefully planned 45

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alcohol program, urged the use of pure (190-proof or 90 % ) alcohol, rather than blends. They argued that "captive" markets existed, farm tractors for example, which could support such a program and that the use of pure alcohol rather than blends wou ld eliminate the greatest short-coming of the earlier program. Willkie and Kolachov's proposal was published on the very eve of America's entry into the second World War. It represented the culmination of one of the We must recognize the vital importance of developing renewable resource bases for our energy needs strongest arguments in the "chemurgy" program of the 1930's, conversion of grain surpluses to power alcohol. The exigencies of a war economy, however, overwhelmed it. Grain surpluses disap peared as we were called upon to feed our allies during the war and much of west ern Europe after it. There was considerable production of alcohol from grain during the war but this was needed to supply increased industrial requirements and to rep la ce the imported molasses previously used. Since 1945 the United States has helped to supp ly the food needs of nations which had pre viously been cereal grain exporters but whose population growth had outstripped their own productive resources. The grain surpluses of earlier decades steadily dwindled away until, in the 1970's, we encountered shortages, for export at least, and rapidly increasing prices. Even in this unfavorable climate, the possibility of pro ducing alcohol from starch for motor fuel use has been resurrected [15, 16]. In 1971 the Nebraska Legislature took the first positive step w ith pas sage of a law [17] providing for an allowance of 3-cents per gallon on the state motor fuel tax when fermentation ethanol is added to lead-free motor fuels. As the specter of fuel shortages be came more real, pressure for the use of "gasohol," a 90 % gasoline-10 % alcohol blend increased. One Nebraska legislator suggested last year [17] that should gasoline prices rise to 65-70 cents per gallon, alcohol would become c ompetitive. At the same time that these predictions were being offered, however, the viole nt s hifts in the world's grain markets experienced over the last year were just corning into play. These dim the prospects for grain -ba sed ethanol for motor fuel just as petroleum price increases favor it. Once again we see at work the increasingly close inter 46 actions between food and energy production previously outlined in Figures 3 and 4. ALCOHOL FROM CELLULOSE THE HYDROLYSIS OF cellulose to glucose by various agents has held the interest of gene rations of applied scientists. Acid saccharifica tion processes were described early in the 19th century and were successfully employed in Europe, especially Germany [18 ] Much of the glucose produced was then fermented to ethanol. Alcohol has also been produced commercially from the sugars in waste sulfite liquors and other similar materials [18]. Acid hydrolysis of cellu lose is an expensive, relatively low-yield process, however, and the advantages of enzymatic pro cesses were recognized early. Unfortunately satis factory cellulase preparations were not available. More recently, however, the technology of c ellu lase preparation and its application has developed rapidly [19, 20]. Yields of glucose from waste cellu los e of 50 % and greater have been reported [21] Cost estimates for the enzymatic production of glucose from cellulose vary widely, however, because of still unresolved q uestions about the amount of pretreatment necessary. Using a range of glucose costs covering most of the predictions made so far, plus past experience with ethanol fermentation costs, it is possible to estimate costs for ethanol production from cellulose (Table 2). These estimates include a rough credit for the protein-rich "distillers solubles" which are pro duced as a by-product but they do not include any credit for the elimination of solid wastes, mixed municipal refuse (MMR) for example, which may be applicable. One should properly ask, "How much alcohol could be produced in this way and what impact, if any, would this have on the nation's fuel needs?" At this point the only answer to this question must be a crude estimate. We are said to produce about 200-million tons of MMR per year in the United States and these solid wastes are about half cellulose Assuming demonstrated yields for glucose from waste cellulose and ethanol from glucose, these wastes could yield 25-million tons of ethanol, or about 8-billion gallons (190proof), per year. This is equivalent to 0.58 x 15 m BTU / year. Current U.S. gasoline consumption is about 100-billion gallons or 11.5 x 10 15 BTU per year. Conversion of all our MMR to ethanol would therefore provide only 5 % of the energy now con sumed in gasoline engines. Even so this fraction CHEMICAL ENGINEERING EDUCATION

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TABLE 2 Cost of Ethanol From Cellulose Glucose cost Raw material C onversion Total $0.10 / lb $1.38 $0.15 0.30 ( 1 ) $1.53 1.68 (0.10 0.15) (2) (1.48 1.53) 0 .05 / lb 0.69 0 .1 5 0.30 0.84 0.99 (0.10 0.15) (0 79 0.84) 0.01 / lb 0 14 0 15 0.30 0.29 0.44 ( 0.10 0.15) (0.24 0 29) (1) High e r estimate based on past experience in production of et hanol from waste su lfit e liquor; low er esti mat e by author. (2) Figur es in parantheses refle ct higher credits for conversion by-products utilized in animal feeds is not significant, especially if the use of fuel al cohol were concentrated in captive services for urban areas These services-street level trans portation, delivery vans, refuse trucks, etc.-are major contributors to urban air pollution and the employment of ethanol as a fuel would be par ticularly advantageous in reducing emissions. SUM MAR Y A N D CO N CLU SIO NS A NUMBER OF ARGUMENTS have been put forward in this discussion and I will con clude by summarizing what I believe to be the most important of these: We must recognize the vital importance of developing renewable resource bases for our energy needs. Ethanol is the only reasonable candidate fuel for in ternal combustion engines which may be derived from renewable resources. While it is unlikely that ethanol can supply a substantial portion of the total national requirement for such fuels, it could contribute sig nificantly to captive market needs in urban areas. Finally, I am convinced that most current assessments of the future potential for various fuels are unrealistic because they are based on established ratios between energy and other costs. The problem is not simply a matter of providing inflationary allowances in cost pro jections It is a question of the essential relationship between the future cost of energy from conventional sources and the other costs involved in fuel production. Energy intensive technologies, e.g. shale oil, coal con version, etc., will suffer increasing penaltie s as the relative cost of energy rises and projection s based on past energy cost experience are bound to be in error. D REF E RE NC ES 1. Cook, E., "The flow of e nergy in an industrialized socie ty," Scientifi c American September 1971. 2. Heichel, G. H., Comparative Efficiency of Energy Use in Crop Production, Bull. 739, Connecticut State Agricultural Experiment Station, New Haven (No vember, 1973). WINTER 1975 3. Rozenzweig, M., and Ushio, S., "Protein from methanol," Chem. Engr., January 7, 1974, p. 62. 4. ---, Chem. Engr. News., April 22, 1974, p. 29. 5. Szego, G. C., and Kemp, C C., "Energy forests and fuel plantation s, C h e m tech, 275 (May, 1973). 6. Klass, D. L., "A perpetual methane ec onomy-is it possible?," Chemtech, 161 (March, 1974). 7. Rainbow, C., and Rose, A. H. Bio c hemistry of In dustrial Microorgani s ms, Academic Press, London (1963) 8. Stodola, F. H., Chemical T ransformations by Micro organisms, Wiley, N. Y. (1958) 9. H erric k, H T ., "New and better uses for our crops," in Crop s in Peace and War ; the Y ear book of Agri cu ltur e 1950-1951, p. 6 9, U. S. Government P rin ting Office, Washington (1951). 10 Davis, J. C., "Chemurgy's second co ming," Chem. Engr., !). 90, April 29, 1974. 11. Klass D. L., and Ghosh, S., "Fuel gas from organic wastes," Chemtech, 689 (November, 1973). 12. Jacobs, P B., and Newton, H. P., Motor Fuels from Farm Products, USDA Misc. Pub. No. 327, Washing ton, D. C (December, 1938). 13. Hilbert, G. E., Alcohol from Agri c ultural Sources as a Potential Motor Fu e l, USDA Publication AIC-233 (Rev.), Washington, D. C. (February, 1950). 14. Willkie, H F and Kolachov, P. J ., Food for Thought, Indiana Farm Bureau, Indianapolis, Ind. (1942). 15. Miller, D L. "Industrial alcohol from wheat, Sixth National Wheat Utilization Conference, Oakland, California, November 5-7, 1969. 16. Miller, D. L., "Fuel alcohol from wheat," Seventh National Wheat Utilization Conference, Manhattan, Kansas, November 3-5, 1971. 17. ---, Chemical Week, p. 24, April 4, 1973. 18. Prescott, S. C ., and Dunn, C. G., I ndustrial Micro biology, 3rd Ed ., McGraw-Hill, N. Y. (1959) 19. Hajny, G. J., and Reese, E. T. C e llulas es and their Applications, Advan ces in Chemistry Series, No. 95, American Chemical Society Washington, D. C. (1969). 20. Ghose, T K., and Ko s tick J. A., Biotech. Bioengr., 1 2 921 (1970) 21. Brandt, D., Hontz, L ., and Mandels, M., AIChE Sym posium Series No. 69, 127 ( 197 3 ). 47

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BOOK REVIEW: Schultz (Continued from page 31.) There is one chapter devoted to polymerization, but it would not satisfy most people who include such material in an introductory course. There is a uniqueness in the first four chapters, however, that will appeal to materials science specialists, especially those who are interested in interdisciplinary approaches to materials science. After an introductory description of the shape, configurations and conformations of polymer molecules, Professor Schultz embarks on a clear and carefully written exposition on polymer crystal structure. He introduces the reader to the morph o logy of single crystals through the tech niques of microscopy. He discusses the principles of electron microscopy and electron diffraction and then interprets pictures of polymer crystals in a very readable manner. He repeats the process using data from optical microscopes, dark field methods and polarized light techniques. This seems to be a particularly appealing way to intro duce the subject matter. The physical structure of polymer crystals is complex indeed, and the interpretation of microscope pictures is usually a very frustrating experience for those who are inexperienced in the subtleties of microscopy. Professor Schultz tries to interpret through words and supplementary sketches what is not evident to the untrained eye. The study of poly meric crystals through small angle X-ray scattering and study of the details of molecular arrangement through NMR and infra-red tech niques are also covered in the second chapter. He includes a few exercises for the students and presents an extensive bibliography that will be very useful to a researcher in the field. The third chapter starts with a qualitative description of crystals formed from the melt, with a clear ex planation of why they are different from those formed from a dilute solution. This is followed by a description of spherulite morphology on morph ology. An up-to-date bibliography is again in cluded. The fourth chapter is devoted to a de finition of degree of crystallinity in terms of the variety of experimental techniques used for its measurement. It is not until Chapter 9 that Professor Schultz completes his exposition on crystallinity by including a very good chapter on crystallization kinetics and mechanisms. Chapters 1 to 4 and 9 constitute one of the 48 better introductory discussions of polymer crystal structure. I wish these 265 or so pages had con stituted a smaller, less expensive book that could have been purchased as a supplement to a more general text in polymer engineering. The material in the remaining six chapters is presented clear ly and the quality is commensurate with the other introductory textbooks in the field, but the sub jects are only loosely connected, show less depth and are considerably less original in the mode of presentation. The trouble is that everyone has his own ideas about how to present the remaining material in a classroom situation and there is not enough material in these chapters to supplement in-depth lectures. Whereas the material on crystallization is so well done that most instruc tors will defer to Professor Schultz's approach, the remaining material is too sketchy for self study and too weak to compete with each person's own ideas. In Chapter 7, for example, the average student will become lost in a maze of equations describing rubber elasticity without developing much appreciation of the properties of rubber. He would be better advised to read a standard treatise on rubber elasticity for the kind of in formation that is presented here in abstracted form. After the section on rubber elasticity, con tinuum mechanics is introduced in order to explain the effects of fillers. This is just too much material for the average student to handle alone. The average instructor with a serious interest in this material will not introduce it in such a superficial manner, while the instructor with a more qualita tive interest will not wish to introduce so many abstract quantities. The degree of superficiality leads to misinterpretation in several places. For example, the presentation of data on the effect of fillers on glassy polymers (Figure 7.16) and the development of the Kerner equation are inter laced with discussions of the effects of fillers on elastomers without clarifying the important differences between rubbery and glassy matrices. Similar comments can be made about the short sections on viscosity and fracture, the brief chapter on time-dependent properties and the surveys of Chapters 10 and 11. All things considered, I found this to be a very good text for an introductory course that emphasizes correla tions between structure and properties. Also, if one is planning to do research in the area of polymer crystal structure, this book gives an excellent introduction to the field. I certainly would buy a copy for my own book shelf and I have no hesitation in recommending it to my students and colleagues. D CHEMICAL ENGINEERING EDUCATION

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