Front Matter
 Table of Contents
 Murder at Miskatonic - Passion,...
 Equilibrium-Staged Separations...
 XSEOS: An Open Software for Chemical...
 Lactose Intolerance: Exploring...
 Group Projects in Chemical Engineering...
 On-the-Job Training
 PID Controller Settings Based on...
 Integrating Environmental Management...
 Challenges of Implementing a Joint...
 Back Cover

Chemical engineering education
http://cee.che.ufl.edu/ ( Journal Site )
Full Citation
Permanent Link: http://ufdc.ufl.edu/AA00000383/00175
 Material Information
Title: Chemical engineering education
Alternate Title: CEE
Abbreviated Title: Chem. eng. educ.
Physical Description: v. : ill. ; 22-28 cm.
Language: English
Creator: American Society for Engineering Education -- Chemical Engineering Division
Publisher: Chemical Engineering Division, American Society for Engineering Education
Publication Date: Spring 2008
Frequency: quarterly[1962-]
annual[ former 1960-1961]
Subjects / Keywords: Chemical engineering -- Study and teaching -- Periodicals   ( lcsh )
Genre: serial   ( sobekcm )
periodical   ( marcgt )
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 rights reserved by the source institution and holding location.
Resource Identifier: oclc - 01151209
lccn - 70013732
issn - 0009-2479
sobekcm - AA00000383_00175
Classification: lcc - TP165 .C18
ddc - 660/.2/071
System ID: AA00000383:00175

Table of Contents
    Front Matter
        Front Matter 1
        Front Matter 2
    Table of Contents
        Page 61
    Murder at Miskatonic - Passion, Intrigue, and Material Balances: A Play in Two Acts
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
    Equilibrium-Staged Separations Using Matlab and Mathematica
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
    XSEOS: An Open Software for Chemical Engineering Thermodynamics
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
        Page 80
        Page 81
    Lactose Intolerance: Exploring Reaction Kinetics Governing Lactose Conversion of Dairy Products within the Undergraduate Laboratory
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
    Group Projects in Chemical Engineering Using a Wiki
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
    On-the-Job Training
        Page 96
        Page 97
    PID Controller Settings Based on a Transient Response Experiment
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
    Integrating Environmental Management by Introducing an Environmental Management System in the Student Laboratory
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
    Challenges of Implementing a Joint Industrial-Academic Research Project as Part of a Nontraditional Industrial Ph.D. Dissertation
        Page 112
        Page 113
        Page 114
        Page 115
        Page 116
    Back Cover
        Back Cover
Full Text

Advice to Authors for an Editorial Contribution

to CEE

Chemical Engineering Education publishes editorials, usually invited, on subjects of current relevance to the
community.The topic is normally controversial and the author is encouraged to clearly state his or her opinion
on the issue and the rationale for the stated opinion.

Recent editorial topics include:
Wankat Winter 2003 "Tenure for Teaching?"
Edgar Spring 2003 "ChE Curriculum of the Future: Re-Evaluating the
Process Control Course"
Doraiswamy Summer 2003 "Whither Chemical Engineering Research?"
Woods Winter 2004 "For the Sake of Argument...Who Will Teach the Core
ChemE Courses?"

The editorials are onejournal page (-600 words) in length and should be submitted electronically to cee@che.
ufl.edu. Although they are not reviewed, the editors do provide feedback on occasion. As always, CEE reserves
the right to make editorial changes or to refuse to publish material that the editors consider to be inappropriate.
The deadlines for inclusion in each issue are:

Winter issue October 15
Spring issue January 15
Summer issue April 15
Fall issue July 15

Note that the Fall issue is dedicated to graduate education. Should you have any questions, please contact us
at cee@che.ufl.edu

Standards for Articles

in CEE

Submissions to CEE continue to increase. This
increase indicates that there is a high and increasing
interest in improving chemical engineering education.
CEE will best serve the education of chemical engineers
if its standards remain high.
Educational papersshould be prepared with thesame
care as technical papers; however, the style can be
more informal and some use of thefirst person is often
appropriate. Papers need to reflect knowledge of the
engineering education literature in addition totheap-
propriatetechnical literature.Asan absolute minimum,
authorsshould search theliterature, readanyarticleson
related topics, and cite appropriate papers. Of course,
morethan theabsolute minimum is normallyexpected,
and authors should do a reasonably diligent search of
other relevant engineering education journals such as
the Journal of Engineering Education (http://www.
asee.org/publications/jee/index.cfm), Proceedings of
ASEEAnnual Conferences (http://www.asee.org/confer-
ences/v2search.cfm), Proceedings of ASEE Frontiers
in Education (FIE) Conferences (http://fie.engrng.pitt.
edu/), International Journal of Engineering Educa-
tion, and European Journal of Engineering Education
a largefraction of what the authors intend to cover has
already been covered,theyshouldconsiderreducing the
paper to an Educational Brief or scraping the project
altogether. Papers must be related to theteaching and
learning of chemical engineering-purely technical
papers are rarely published.
Can papersthat have been published in a nonarchival
medium such as the ASEE Proceedings, published as a
Web page, or were presented as a lecture be submitted
to CEE? Since CEE provides a different audience and is
archived, the answer is yes as long as such publication
would not violate copyright agreements. Of course, the
original publication needs to be cited. If large parts of
the paper are identical to the original paper, this over-
lap should be identified (e.g.,"Parts of this paper were
previously published in .. .). Republishing is most
appropriate when the original publication consisted of
preliminary results that can be expanded upon in the
CEE article.The original presentation venueofa lecture
should be acknowledged (e.g.,"presented as a Plenary
Lecture at the International Conference on Engineer-
ing Education 2004 (ICEE04), University of Florida,

Gainesville, FL, Oct. 19, 2004"). Obviously, lectures
need to be recast into the proper format for an article.
All such submissions will undergo the normal edito-
rial and peer-review processes. Articles that have been
published in or are being considered by other archival
journals should not be submitted to CEE.
Although copyright protection in a digital era is
complicated, for the purposes of CEE the following
standards should be followed. First, unless you know
otherwise, assume that every source (even an e-mail
message) has copyright protection. Authors who want
to copy substantial portionsfrom an article (a complete
table orcompletefigure ora substantial portion of the
text), any portion of a song, or any part of a poem are
responsiblefor obtaining permission from the owner
of the copyright. This is often the publisher, not the
original author. Since copyright refers to the form of
the presentation and not the underlying data itself, if
you totally recast the data (e.g., convert a table into a
plot) permission is not required. Of course, whether
or not permission is required, appropriate quotation
procedures should befollowed and the sources must
be appropriately cited. Even when you are the original
author, you must askthe copyright owner for permis-
sion to reuse your own work. As a rule of thumb, if a
copyrightform wasfilled out, you probably transferred
copyright to that publication.
Plagiarism and self-plagiarism (reuse of your own
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citation procedures) of copyrighted material owned by
someone else is illegal. Even if copyright permission is
not an issue, plagiarism and self-plagiarism are viola-
tions of CEE standards. In practical terms this means
that you can't cut and paste material from one of your
articles and reuse it in a new CEE article unless the
original source is cited. If the original source is a CEE
paperandyou are preparing a newCEEpaper,do notcut
and paste any ofthetextto saveyourselftime-rewrite
it. Only parts that are absolutely necessary such as a
table orfigure should be reused, and then the original
source must be clearly identified.
Failure to meet any of the CEE standards is likely
to result in rejection of the paper. Authors who fail to
meetthe standards involving copyright, plagiarism and
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papers to CEE.

Chemical Engineering Education
Department of Chemical Engineering
University of Florida * Gainesville, FL 32611
PHONE and FAX: 352-392-0861
e-mail: cee@che.ufl.edu

Tim Anderson

Phillip C. Wankat

Lynn Heasley

James O. Wilkes, U. Michigan

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John P. O'Connell
University of Virginia

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Rowan University

University of Colorado
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University of Florida
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Princeton University
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University of Texas at Austin
Richard M. Felder
North Carolina State University
H. Scott Fogler
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University of Tennessee, ( ....,,,, .,
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University of Toledo
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University of Michigan
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University of Delaware
Donald R. Woods
McMaster University

Chemical Engineering Education
Volume 42 Number 2 Spring 2008

96 On-the-Job Training
Richard M. Felder

74 XSEOS: An Open Software for ChE Thermodynamics
Marcelo Castier
91 Group Projects in Chemical Engineering Using a Wiki
Jeffrey J. Heys

105 Integrating Environmental Management by Introducing an Environmen-
tal Management System in the Student Laboratory
Maria T Montaids and Antonio E. Palomares

82 Lactose Intolerance: Exploring Reaction Kinetics Governing Lactose
Conversion of Dairy Products Within the Undergraduate Laboratory
Jimmy L. Smart
98 PID Controller Settings Based on a Transient Response Experiment
Carlos M. Silva, Patricia F Lito, Patricia S. Neves, Francisco A. Da Silva

112 Challenges of Implementing a Joint Industrial-Academic Research
Project as Part of a Nontraditional Industrial Ph.D. Dissertation
Jeffrey R. Seay and Mario R. Eden

62 Murder at Miskatonic-Passion, Intrigue, and Material Balances: A Play
in Two Acts
Jake Vestal
69 Equilibrium-Staged Separations Using Matlab and Mathematica
Housam Binous

90 Call for papers

CHEMICAL ENGINEERING EDUCATION (ISSN 0009-2479) is published quarterly by the Chemical Engineering
Division, American Societyfor Engineering Education, and is edited at the University of Florida. Correspondence regarding
editorial matter, circulation, and changes of address should be sent to CEE, Chemical Engineering Department, University
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Vol. 42, No. 2, Spring 2008

MR]!1 -class and home problems


Passion, Intrigue, and Material Balances:

A Play in Two Acts

N.C. State University * Raleigh, NC 27695
Dramatis Personae
Dr. Alexander Verawood: Late and notable professor of engineering at the Miskatonic
University of Arkham, Massachusetts.
Dr. Xavier Verawood: Alexander's younger brother.
Richard Pendleton: Alexander's personal assistant.
Gabriella de Morcef: Graduate student in the laboratory of Alexander.
Thaddeus Hardcastle: Powerful tycoon with ethically questionable business tactics.
Aurora Simonova: Alexander's mistress.
Zelda Verawood: Alexander's wife.
Dr. Errol Curry: Miskatonic engineering professor; colleague of Alexander.
Tommy Benedict: Custodian for the Miskatonic U. Chemistry and Engineering building.
Jake Vestal is a chemical engineering senior
"Thank you Pendleton. Just park here and we'll go in to- at North Carolina State University and plans
.... iI. . it's much too cold for you to wait in the car." to earn a Ph.D. in ChE after he graduates. He
enjoys studying Logic and Game Theory, in
Dr. Xavier Verawood and Richard Pendleton climbed which he is earning a minor from the Math-
ematics Department. Jake is passionately
the stone steps of the Miskatonic University Chemistry and fond of the board game "Go."
Engineering building ; ...-. i,,. After passing ;1r.... 1, the
large wooden doors at the entrance, they approached the

� Copyright ChE Division of ASEE 2008
62 Chemical Engineering Education

The object of this column is to enhance our readers' collections of interesting and novel prob-
lems in chemical engineering. Problems of the type that can be used to motivate the student by
presenting a particular principle in class, or in a new light, or that can be assigned as a novel home
problem, are requested, as well as those that are more traditional in nature and that elucidate dif-
ficult concepts. Manuscripts should not exceed 14 double-spaced pages and should be accompanied
by the originals of any figures or photographs. Please submit them to Professor James O. Wilkes
(e-mail: wilkes@umich.edu), Chemical Engineering Department, University of Michigan, Ann
Arbor, MI 48109-2136.

entrance to the Research Level, where the secretary greeted
them, making a note of their arrival in the log, like this:
"Verawood, Xavier, and Pendleton, Richard: in 8:40 a.m.,
21 Nov. 1932." The pair continued past the desk ;1,r. ,. .1, the
well-lit hall and descended to the basement. Halfway down
the corridor Xavier opened the laboratory door of the great
Dr. Alexander Verawood, his brother and the reason for his
visit, and stepped in.

The room was dominated by a huge copper tank, taller than
Xavier and polished to a bright orange luster. It was feeding
from a collection of tanks that surrounded it as it brooded
in the center of the room. From the top and sides of the ves-
sel sprouted a multitude of thin pipes that stretched out like
tendrils from a vast and carnivorous jungle plant. Each line
snaked its way to one of many contraptions on sturdy tables
arrayed upon the flagstones of the lab 's floor, or to a wall rack
where an amber-colored liquid was subjected to the.. .,nlil. t
of a multitude of delicate glassware and shiny metal, which
looked to Verawood like some kind of glittering alchemy.
The place smelled, strangely, like a bakery next door to
an auto garage, and it resonated with a humming sound and
a 1,.., ,i., pulse like a slow heartbeat. Every now and then
pressure was released from somewhere in great puffs, and a
large mercury thermometer on the wall proclaimed a warm
temperature of 77 "F. The pair was hailed by a voice from
across the room.
Xavier turned to see a very small, dark-haired young woman
whose large brown eyes stood out starkly ,,. .,. ,1i i ,,.- white of
her lab coat. She was wheeling a cart that bore several very
large tanks to a corner of the room. Xavier and Pendleton
helped her wrestle the tanks off the cart and onto the floor,
where they were safely chained to the wall.
"Thank you," said the woman, brushing away a strand of
black hair. "Those empty CO2 tanks were left somehow over
there next to the full ones. It's lucky they were still on the cart;
they're very heavy and quite cumbersome to move around.
Are you here to see anyone? "
Pendleton noticed that a few of the tanks in the lab were
painted a brilliant blue and sported proud labels ~. .iir., "The
Blue Boy: 2ft3, Guaranteed to 3000psi." He remembered how
the Professor, his employer, had once performed a certain
favor for Warrington Industrial, the maker of the Blue Boy
tank, and as a result found himself supplied with gas storage
practically to his heart's content.
"Yes, ma'am, I'm Xavier Verawood, brother of the Profes-
sor, and I think you must already know Richard Pendleton, my
brother's assistant. I arrived from Geo'i ia last night."
"Of course, Dr. Verawood, your brother has told me about
you. Aren't you a professor of Medieval and Renaissance
Literature at Emory? My name is Gabriella de Morcef; I'm
your brother's graduate student. What can I do for you?"

"Well, I did come here to see the Professor, but if it's not
too much of an inconvenience I was rather hoping you could
explain this cyclopean monstrosity to us," Xavier said, mean-
ing the huge copper tank. "It looks terribly interesting, but
I'm afraid I must humbly confess to a deplorable ignorance
of chemistry and mathematics. And, please, call me Xavier: I
still haven't quite ,,ou,,e used to 'professor'or 'doctor'."
At this, Gabriella lit up. "Of course! Follow me to the
incubator: This is where it all starts."
Intrigued, the two men allowed themselves to be swept in
the wake of the tiny scientist, who led them to the monolithic
bronze tank in the center of the room. Opening a slide in the
outer casing of the incubator, Gabriella exposed a view cell
;.l'. .,i 1, which a churning amber liquid could be seen swirl-
ing against the glass.
"It's fortunate that you arrived on a collection day; oth-
erwise you wouldn't have seen the lab in all its splendor,"
she said.
"Now, this yellow liquid that you see ;1,i.. ,i., I the glass is
really an aqueous solution of yeast cells, kept at 37 "C in a
mixture containing one part tryptone and other proteins-
that's milk; well, more or less," she added as an aside, before
ticking off the remaining ingredients. "One part NaC1, some
glucose, and a dash ofMgCl.
"These tanks that you see surrounding the incubator all
contain 02 or CO2. The CO2 feed is part of a buffering sys-
tem we use to keep our yeast cells producing their wonderful
chemicals that this lab is dedicated to studying. Oil,, i ,., i ..,,,
are mixed in with the solution, but they vary with the experi-
ment that is being performed.
"As you must know, yeast cells are able to produce ethyl
alcohol ;il1 . i , fermentation; this is how beer is made. This
lab is really quite like a plant, a brewery if you will, except
we have found that we can coerce our little yeast cells to
produce amazing hydrocarbons that can be modified for other
uses, chiefly for fuel and industrial-lubricant applications.
The trick is a combination of the proper choice of media and
correct treatment of the cellular products. Essentially, we
are using the machinery that already exists within the yeast
cells to make our product! You can surely see how these very
processes might drastically reduce our dependence on oil,
and perhaps even eliminate it."
Here, Gabriella indicated the lines that radiated out from
the incubator.
"On a collection day, the yeast solution, which by now con-
tains our hydrocarbons of interest, is being sent off 1;-. .,., 1
this network of tubes to stations where various components
alter the yeastfeed. In the business, we call this a 'semi-batch'
process. You can see on the wall there one of our distillation
units; that particular component happens to be purifying the
n-octane that the yeast cells have produced. The cells are be-

Vol. 42, No. 2, Spring 2008

"As for the methane/ethane waste, it's piped into that Blue Boy over there on the bench. Every Friday
after he makes dinner the Professor tops it up to 1500 psig, then when he wants, he opens up a little
valve under his desk, allowing fuel to flow from that tank to his office."

ing lysed by a detergent, releasing the n-octane and forming
a slurry of media, octane, and dead cell debris. From there,
the mixture is heated and subjected to fractional distillation;
thus, the octane is readily recovered. Each component that
you see is doing essentially the same ;1,, i. It's either autono-
mously wa , t :i. % ,i ,. , ..,,,. ii, it., or ,,. '- . 'n I,., some important
component of the virgin yeast feed that we might find to be
a useful fuel or lubricant. It's really a very simple process if
you think of it in pieces."
She smiled expectantly. Xavier tried not to let his eyes cross,
but Pendleton simply nodded serenely. Xavier blushed,feeling
like he had to ask .ii,,. l,,i., in order to avoid looking dim.
"Does i,. i,,iit. go to waste?" he blurted.
"Very astute, professor. Yes, the methane and ethane that
we necessarily produce are useless. Stoichiometrically speak-
ing, we produce about three times as much methane as we do
ethane, and we used to just burn it all off to get rid of it. CO2
is also produced; the yeasts respire just as you and I do. That
extra CO,, however, is taken in tanks, on the cart that you
helped me with, to photosynthetic algae that we grow on the
roof in clear containers. There, the algae produce the sugars
that we use in the yeast media in a CO,-rich environment. We
could, of course, be purchasing or using atmospheric CO,,
but why should we when we're producing it ;. liit here in
this room? Further, what we're really trying to do is set up
a ..i ,. i, model of a plant that might someday operate on
a near-closed cycle that couples the 3,.. i % '., i..- i g-molecule
exchange in order to supply us with cheap and virtually infinite
fuels and lubricants. In the realplant, the CO, would probably
just be piped into the algae tanks automatically with the rest
of the yeast products.
"As for the methane/ethane waste, it's piped into that Blue
Boy over there on the bench. Every Friday after he makes
dinner the Professor tops it up to 1500 p-'-.. then when he
wants, he opens up a little valve under his desk, allowing fuel
to flow fom that tank to his office.
"There, he has a clever little burner of his own design that
he managed to coax into ('.,. m.irt,., at 90% efficiency. He's
even constructed a marvelous little carburetor that draws the
perfect amount of oxygen into the flame chamber; I saw it
heat a pint of water up to boiling in only three minutes when
I had coffee with him last week. The secret is that the rector
geometry allows the fuel to combust virtually completely. I
only hate how he uses the,;h,,r. with the door closed, but he
claims that the little bit ofCO2 and water vapor that the burner
produces is good for his office plants-one of his many ec-
centricities, I suppose." She ' i.1,,., "He really is a brilliant

man, hates to waste ita ilr,, i. at all, even ;li ..l,, .1 we do wind
up having to dump what he can't manage to reuse."
"He's been like that since childhood, Miss de Morcef, I can
assure you," said Xavier, glancing at the tank, whose gage
now read 713 psig. "Is he in? I should very much like to see
him; in fact, that's the reason I came to Massachusetts. I stayed
at his house last night, but you know how he gets so involved
in his work that he winds up ,1... / ,i-,,. here."
Gabriella nodded. "His new office is next door to the left. He
took it because it's close to the lab; it's really not much more
than a converted utility closet that was put into this basement
when it was renovated. I would walk you there, but it's never
good to leave a high-pressure process unattended if one can
help it, so you must forgive me. It was nice meeting you."
The two men departed to Dr. Verawood's office, which was
out of the lab and next door, as they had been instructed.
Xavier smelled the freshly painted walls and enjoyed the
clop-clop of his shoes on the floor of the newly renovated
hallway, while Pendleton silently noted the ventilation strips
along the ceiling and floor g-molding. They were probably
explosion-proof he ;i*ir. i, l. andi. ito .ail it mo,., to prevent
the buildup of dangerous gases in the basement.
The pair found a handsome hardwood door bearing the
name "Dr. Alexander Verawood" on a golden strip. Both men
noticed a strange smell that seemed to be leaking out from
the large gap underneath the Professor's door, no doubt put
there in order to facilitate the slipping in ofpapers by students.
Xavier knocked, but received no reply.
"Well Pendleton, he's either enl' o % %'ed in some great work
or asleep. There's no lock on this door; I'm sure he won't
mind if we go wake him up."
"Of course he won't mind, Dr. Verawood; he's been very
excited about your coming for two weeks now."
Xavier turned the knob and pulled the door open. Immedi-
ately he uttered a choked gasp, cut short by the noxious rush
of a malignant vapor, which smelled unmistakably like fuel
gas. Pendleton coughed and sputtered as well, but retained
the presence of mind to slap Xavier 's hand away from the
light switch towards which it was creeping, thereby avoid-
ing the chance of a quick spark followed by an unfortunate
"Ghastly smell, that. What's theprofessor been..." he was
stopped by the expression of horror on Xavier's face. When
Pendleton followed his gaze into the office, he saw what had
upset the young professor.
There, on the floor of his own office, sprawled on the rug
that he and Xavier had brought back from China, was the

Chemical Engineering Education

great Dr. Alexander Verawood. He was cold, pale, and as
dead as the flagstones he lay upon. Pendleton, falling to his
knees from the onslaught of the horrible fumes and the sud-
den dull anguish that gnawed at his stomach, picked up the
Professor 's hand to check for a pulse. As he did so, Xavier
noticed a pad of paper near the Professor 's elbow bearing
a single word:

"Monstrous!" cried Xavier that evening, in his late
brother's study at the Verawood family mansion. He was
reflecting upon the day's events, of how they had moved his
brother's body to the Verawood family vault with the help of
a trustedfamily physician. First, ;,I..-. I1. Xavier had had to
fumble for the supply valve in order to shut off the gas that
was pouring forth from his brother's unlit burner. Luckily, they
had been able to get the body out of the building by placing
it in a black bag on a cart and claiming that it was a delicate
piece of equipment that someone in the physics building had
requested to borrow for a while.
Faraday, the family physician (to whom the Professor's
last note was not mentioned), had performed an autopsy that
afternoon with the conclusion that Verawood had died of a
heart aiiack. I laddeningly, no traces ofpoisons, cuts, bruises,
or any other trauma had been found anywhere on or in the
late Professor 's mortal coil.
"How could this have happened? What callousfiend could
be responsible for such a heinous act! Oh, Pendleton, what
are we to do?"
"Courage, Doctor, courage, there's hope yet. We won't
find your brother 's assassin by useless raving, but by logic.
I must admit ;i... 1i,. it's rather puzzling. Perhaps we should
involve the police?"
"Not on your life, Pendleton, not with that Hardcastle
around. He probably owns every policeman in Massachusetts
by now. The murdering ;1, . ' I'm sure it was him, he's been
hounding my brother since the beginning of the yeast proj-
ect, and we know he was there the weekend of the murder!"
Xavier was shouting.
"That's a circumstantial accusation, and you know it. Sit
down and I'll have Doris bring us some wine and whatever
is left from that roast we ate last night."
Xavier moved from the window to the soft suede chair
beside the bookshelf where his father used to read Goethe
on rainy nights.
"Do you think there's such ;1,,r. as the perfect murder,
Pendleton?" he asked, despondently looking out at the cold
"No. You should know that. .'. .i,,ii. in the real world cor-
responds exactly to its ideal counterpart, ;1. ., I it can get

very close. Perfection only exists in mathematics. No, your
brother 's murderer made at least one mistake, maybe more,
and it's up to us to find it and exploit it."
Doris arrived with the roast and a bottle of Burgundy. The
two men moved to the heavy wooden table near the short wall
of the room, which was still somewhat cluttered by Alexander 's
notes and calculations. After ,. iiir. down thefood and drink,
Doris slipped out, n,. ii., i,. that the two were deeply engaged
in conversation. Xavier took a bite of his dinner.
"That feels better, I think we can get on with it now," he
Pendleton nodded, as Xavier took a solemn breath, then
continued. "Let's start at the beginning. We conferred with
the secretary and checked the log, and decided that only six
associates of my brother were present in the C & E building
between the time he was seen at his evening class on Friday,
and 9:00 Monday morning, when we found him."
Xavier found a scrap sheet ofpaper and a pen, and started

"There were six," agreed Pendleton, "All of whom had
some kind of connection or business with your brother."
This is what Xavier wrote down:
1) Thaddeus Hardcastle 2) Aurora Simonova
3) Zelda Verawood 4) Errol Curry
5) Tommy Benedict 6) Gabriella de Morcef

"Why don't we start with old Thaddeus? "
"Very well. We know from the secretary's log that he
visited the Professor on Friday evening, but did he have a
"A motive!" shouted Xavier. "Of course he had a motive!
This is the baron himself we're talking about! He's always
in the papers, in and out of court for the convenient and
'accidental'deaths involving anyone opposed to his jugger-
naut of an oil empire. He's the only one not affected by this
Depression we're in, Pendleton-everyone needs oil. Only
now, he gets to pay his workers less for the same amount of
labor: more people are willing to strain away on his derricks
and rigs because no one can find jobs. Alex's yeasts would
have ruined his entire industry eventually, and he visited my
brother on the weekend he was murdered!"
Xavier was becoming heated, andPe it, 1, . -, itl. it best
to push along the conversation.
"Friday evening, from 5 to 6. Ample time, I should think.
Let's move on to Miss Simonova."
"Well, I won't pretend I don't know what she was, but I
think you know more than I do about her," admitted Xavier.
"Alexander hardly talked about her in his letters. Look, she

Vol. 42, No. 2, Spring 2008

was at the building from 8:30 to 9:30p.m. on Saturday. Tell
me about Aurora, Pendleton."
"She was rather the climbing type, I came to believe, ,;i.. , 1,
I don't insult your brother's taste. Unfortunately, despite my
personal opinions (which reflect somewhat poorly on Miss
Simonova's character), I can't say much about her save one
important detail: she ;1,. .�, l, t1i,. and Alexander were legally
"What?!" scoffed Xavier. "How is that possible?"
"Apparently she convinced the late Dr. Verawood to enter
into some kind of contract with her that she believed legally
tied the Verawood estate to her name. I think a lawyer of
dubious qualifications and reputation was involved, but the

Xavier found a scrap sheet of paper

and a pen, and started writing.

"There were six," agreed Pendleton. "All of
whom had some kind of connection

or business with your brother."

contract will never stand up in a court of law. You can be
certain that your brother knew this. It is, I think, rather akin
to what is often called the 'Vegas marriage.' The point is
I'm rather convinced that at the time of the murder she truly
believed that she stood to inherit all that was your brother 's
upon his demise. Ironic, isn't it, that someone so adroit in the
arena of social interaction should be so naive when it comes
to even the simplest of legal issues? "

Xavier didn't ask how the old servant knew all this; he didn't
want to put Pendleton in the position of admitting to being a
snoop. Instead, he said:
"Well, the next one is obvious. Alex told me in a letter that
Zelda found out about Aurora and that the i,. ,iihilt: tempest
was cataclysmic."
Pendleton shuddered, remembering. "That's not too far
from the mark. Mrs. Verawood has been 'weuin', increasingly
agitated since that day in August, and the onset of winter
has not lifted her spirits. Before she left here on Friday to
stay at her parent's estate, she had taken to brooding in her
rooms. As you know, she's always been one to hold in her
feelings until they compel her to rashness, and when she left
she seemed elated, as if her melancholy had lifted upon the
making of some decision. And she was there, at the C & E
building, from 8-9 p.m. on Sunday."
Xavier hung his head. "I wish that poor Alex's married life
had worked out, but the truth is that they just weren't made
for each other. Naturally I'd like to cite Zelda's intractably

spoiled attitude; I ;,i..-. it her a i ,.: it termagant when Alex
first met her. That's probably prejudice, ;i1. -,i i,. and my
brother ought not to have behaved as he did in his private
life." He shrugged.
"Dr. Errol Curry," said Pendleton.
"Errol grew up with us, as of course you remember. I can
only recall the keen jealousy hefeltfor my brother, who was
always his better in school, sports, and social relations.
Alex treated him very magnanimously, as far as I know, but
I think that that only seemed to infuriate Errol even more.
Alex wrote to me last month and told me that the department,
like c i.. iil,, . else these days, is having serious financial
problems and that one of the faculty would have to be cut.
I'm sure Errol was afraid for his life. The poor man hasn't
done very well recently, or truthfully, at all, and perhaps he
became rather desperate."
"Though I do remember the jealous admiration with which
he regarded your brother in childhood, I cannot lay claim to
any knowledge about his professional situation. Still, we must
include him in our consideration, for he was present at the
building from 9 a.m. to 12 noon on Saturday, and from 9 a.m.
to 8p.m. on Friday. But who is this Tommy Benedict? "
"He's thejanitor," replied Verawood, ' h. * was scheduled
to work this Saturday from 8p.m. to 11 p.m. in the basement
while no one was around. We know that the labs are locked all
iil;. .i,. 1, the weekend, and he had one of the four keys. Curry
and Miss de Morcefhave the other two, I believe, tied as they
are to the university. Alex, of course, had the fourth.
"That's a sketchy connection," continued Verawood, "But
Benedict certainly warrants consideration on circumstance
alone. Now, you said you had i.., ii,,.il,,. to tell me about
Pendleton steepled his hands and took on a rather ironic
\ y/- dear young Master Verawood, you won't believe what
I am about to tell you," he began, "but our Miss Gabriella de
Morcef has an acute case of hallucinogenic paranoia."
"What?! What does that even mean? Could she have killed
"Not only that, but she might not remember it." Pendleton
waited for the implications to sink in.
"The late Professor received a letter from her mother in
southern France. She is, by the way, the progeny of rather
noble French stock on her father's side, but her mother was an
Italian serving girl with whom her father became completely
enamored during a trip to Italy in his youth. She turned out
to be quite a graceful, intelligent, and virtuous woman who
adapted to her new ,i n ,il,. .,., Ili. 1 i .,,,l, l1,..l ,., everyone
around her, much like her daughter Gabriella.
"Your brother always raved about Gabriella's unsurpassed
creative and analytical prowess, how she saw to the heart

Chemical Engineering Education

of even the most complex problems with a quick and sure
dexterity that rivaled his own.
"That letter from her mother, however, told of an incident
that occurred while Gabriella and the f i,,l 1 .... a .... .i. ,,I ,.
in Nice one June. I think that Gabriella's mother felt that Dr.
Verawood should hear about it. The details are delicate and
not pressingly relevant, but the end result was that Gabriella
had an episode in which she felt that her life was in danger
by unseen beings-beings, apparently, that gibbered to her
in the sounds that a wind-flapped shingle made on the roof
of her family's seaside villa. Luckily her father found her
before she could do any harm, for I'm given to understand
that when he entered Gabriella's room he found to his horror
that her terrified little sister was physically restrained and
in danger of ., -. ,. i i. a mortal injury by Gabriella's hand.
Gabriella remembered i.. ,li,,i. the next morning. Since, the
young woman has been treated with medication, which has
eliminated these violent episodes. What concerns me about
this is that your brother told me once, in passing, that she
feels her medicine curtails her higher and more subtle mental
abilities, and that she does sometimes skip her pills."
Xavier remembered the delicate, brilliant woman from the
lab, so excited by her research and full of potential, and he
felt a shiver well up.
"She was there on Friday from 9 a.m. to 5p.m., and again
Sunday evening from 5p.m. to 12 midnight. When we asked
her this afternoon, she said she spent Sunday in the library and
Friday in the lab, and she doesn't recall seeing the Professor
after his evening lecture. Pendleton, what can we say about
the fact that no one reported the Professor's death at all? If
Hardcastle was the one, then my poor brother lay in his office
for the whole weekend while everyone else was coming in and
out; surely someone must have seen the murder scene?"
"True," replied Pendleton, ;,-. .i, ifll., "True. I think that
we must assume that every suspect that might have entered
the building after the murder either 1) didn't open the door of
the Professor 's office or 2) did open the office door, but didn't
report what he or she found, and it's not really too unlikely
that one or the other situation actually occurred.
"The former is not so hard to believe with Curry, Gabriella,
and Tommy, who are likely to have not sought the profes-
sor out and would not have missed his absence. We can be
certain that Hardcastle saw the Professor alive on Friday,
;1,. .,r. I he may have murdered him at that time. IfHardcastle
is not the murderer, then he simply left when his audience
had concluded.
"As for Aurora and Mrs. Verawood... well ... we can't as-
sume that they entered the Professor 's office just because we
know they were in the building. To have both not murdered
the Professor and to have discovered and not reported the
Professor's demise seems unlikely; therefore we can guess

that if one of these women is a murderess then the other one
probably didn't enter the room."
Pendleton had finished and sat quietly, musing. Xavier's
gaze turned again to the window, i1. .-, .1 11,,. It he lookedfor-
lornly at the dark, flowing Miskatonic under the night sky. The
minutes ticked by on the .. . n,, !fil,. I clock that had stood in
the study since his... .,,, lf, I,,. i 's time. Sighing, Xavier looked
back at Pendleton. Curiously, Pendleton was staring intently
at the suspect list, which had been flipped over to reveal some
of the late Professor's old calculation pages, scribbled on the
paper. "What is it, Pendleton?" whispered Xavier.

"I know a little . do,, il,, about logic and engineering after
all my years in this house. Xavier, the murderer can only be
one person: I know how to find out who killed Dr. Alexander
Verawood, and we can do it without leaving the room."

First, it is necessary to determine the old Professor's cause
of death. We only know that there were no marks or trauma on
his body, that he knew he was being murdered (hence the note),
and that a doctor gave "heart attack" as the cause of death.
Now, we must think back to a few details. The Professor's
office is a converted utility closet located underground; prob-
ably having poor ventilation and no windows. Gabriella, the
lab assistant, wheels a cartload of empty CO2 tanks into place
when the two sleuths enter the laboratory; they help her unload
them to the floor. The door to the Professor's office has no
lock on it, but opens outward.
Now we think back to the empty CO2 tanks that Gabriella
was moving. The were too large to move by hand and there-
fore unlikely to be misplaced by chance, which should set
us thinking that CO,, in very large quantities and in a small
space, is as deadly as any poison.
The scene could have played out something like this: the
Professor, minutes before he was killed, was cooking his
evening meal on the little burner. Feeling a little hot under
the collar, he gets up to stretch his legs, only to find that his
shortness of breath gets worse. After a few minutes, he feels
a pain in his chest and, desiring of fresh air, moves to his
door, turns the handle, and pushes, only to find it blocked!
Wondering what the obstruction could be, the Professor must
have kept pushing with increasing worry as his head began
to swim with lack of air. Sinking to the floor, he must have
seen or heard the CO2 being pumped into his office, decreas-
ing the oxygen content of each of his breaths, and must have
realized, at that moment, that his life was in danger. Before
blacking out, he had time to leave his last note.
It was seemingly the perfect crime: no evidence, no fin-
gerprints, no sign of a struggle, no need for the murderer to
even enter the room. However, there was one more thing the
murderer didn't count on.

Vol. 42, No. 2, Spring 2008

When the oxygen concentration of the room dropped, the
Professor's life was not the only thing to snuff out! Indeed,
the burner's pilot light could no longer continue to burn, but
extinguished, allowing pure fuel gas to gush into the room.
This is what Xavier and Pendleton smelled, and was why
they didn't notice how thin the air was, for they were already
holding their breath.
Now, the fuel gas was comprised of a 3:1 mol methane : mol
ethane mixture and stored in a tank with a capacity of 2 ft3
(56.63 L). Making the reasonable assumption that the Professor's
basement office is at room temperature (77 F, 25 �C) and 1 atm,
we use Yaw's Chemical Properties Handbook to calculate the
heat of combustion at 958.9 kJ/g-mol, making the assumption
that the water product of combustion is in the vapor phase.
Gabriella mentions that the burner is 90% efficient and heats
one pint (0.473 L) water to boiling in 3 min. Therefore, the
flow rate of fuel into the burner must be 0.0574 g-mol/min,
assuming everything at roughly STP, assuming that the heat
capacity of water is a constant 4.187 k.I kg K, and assuming
that the density of water at 25 �C is 1 kg/L.
We also know that the 2 ft3 tank was filled up to 1,500 psig

(10,440 kPa abs) before the Professor started using it, and that
it was at 713 psig (5,020 kPa abs) at 9:00 a.m. on Monday.
So, we have only to find how long the fuel had been escaping,
then count backward to find out when the flame went out.
That's easy: using the Ideal Gas Law at the lab temp, which
we know is 25 �C, we find that the difference between the two
pressures of the tank corresponds to a loss of about 124 g-mol
fuel gas. Now, dividing 124 g-mol by 0.0574 g-mol/min tells
us that the fuel had been escaping from the burner for about
36 hours (2,160 min).
Counting backward from 9:00 a.m. on Monday, that means
that the fuel began escaping at 9:00 p.m. on Saturday. There
were two people present in the building at that time: Tommy
Benedict and Aurora Simonova, but only Tommy had the
keys to the lab (which is locked on the weekends) to get to
the CO2 tanks!
It turns out that the Professor, to supplement his skimpy
funds, was running a distillery as a part of his yeast experi-
ments in the basement. This, of course, was a risky occupation
during Prohibition, and so Tommy, who worked for a local
mob boss, was persuaded to eliminate the competition. 7

Chemical Engineering Education

MR]!1 -class and home problems



National Institute of Applied Sciences and Technology
Unit operations are ubiquitous in any chemical process.
One of their main purposes is to achieve separation
in order to recycle unconverted reactants or reach
product purity specifications. If two phases are brought into
intimate contact, a few components migrate from one phase
to the other in every stage of the unit. Then, the two phases
are separated. When we consider equilibrium-staged separa-
tions, we assume that both phases leaving each stage are in
equilibrium and one is richer in one or more components.
The most common unit operation is distillation. It is used,
for instance, to separate crude petroleum into its various
fractions such as kerosene and gasoline. In the pharmaceuti-
cal industry, liquid-liquid extraction is often employed. For
example, antibiotics in aqueous fermentation are recovered
using organic solvents. Finally, absorption and stripping are
often involved in gas treatment plants-such as units used
to remove acid gases (CO2 and H2S) from natural gas. In the
present paper, we solve two problems while showing how
graphical methods can be used to design the unit operations.

* Tunis, Tunisia
The first problem treats liquid-liquid extraction while the
second problem deals with binary distillation.

Problem Statement
We want to separatem acetic acid from water using isopro-
pyl ether in a single-feed countercurrent extractor. Use the

Housam Binous is a full-time faculty member
at the National Institute of Applied Sciences
and Technology in Tunis. He earned a Diplome
d'ingenieur in biotechnology from the Ecole
des Mines de Paris and a Ph.D. in chemical
engineering from the University of California
at Davis. His research interests include the
application of computers in chemical engi-

� Copyright ChE Division of ASEE 2008

Vol. 42, No. 2, Spring 2008

The object of this column is to enhance our readers' collections of interesting and novel prob-
lems in chemical engineering. Problems of the type that can be used to motivate the student by
presenting a particular principle in class, or in a new light, or that can be assigned as a novel home
problem, are requested, as well as those that are more traditional in nature and that elucidate dif-
ficult concepts. Manuscripts should not exceed 14 double-spaced pages and should be accompanied
by the originals of any figures or photographs. Please submit them to Professor James O. Wilkes
(e-mail: wilkes@umich.edu), Chemical Engineering Department, University of Michigan, Ann
Arbor, MI 48109-2136.

The author brings to the reader's attention that a program to determine
the number of equilibrium stages using the Graphical User Interface (GUI)
of Matlab is available.8' This GUI program, written by Claudio Gelmi,
was inspired by the earlier code of Housam Binous.

Hunter and Nash[21 Graphical approach to compute the number
of equilibrium stages required. Assume equilibrium data, at
1 atm and 25 �C, given by Wankat.J11 Solvent and feed flow
rates are equal to 1,000 kg/hr and 1,475 kg/hr, respectively.
Feed, a binary mixture of water and acetic acid, contains 35
wt % acetic acid. We wish to obtain a raffinate with only 10
wt % acetic acid.

0 20 40 60 80 100
wt. frac. water
Figure 1. Equilibrium diagram for the ternary system
obtained using Mathematica.

To study the separation"1] of acetic acid from water using
isopropyl ether for a single-feed countercurrent extractor, we
will use the graphical method derived by Hunter and Nash[21
and later by Kinney[31 to obtain the number of equilibrium
stages required to achieve a particular raffinate specification.
This separation is usually difficult to realize with distillation
due to the presence of a severe tangent pinch at high composi-
tions of water, which prevent the distillate from being acid-
free. A graphical solution performed by hand calculation has
been presented by Wankat.J11 We will show how one can use
Mathematica and Matlab to solve this problem more easily and
accurately using the graphical approach of Hunter and Nash.[2]
Equilibrium data, at 1 atm and 25 �C, are given by Wankat1ll
and can be used to plot Figure 1 -where the tie lines have been
drawn (obtained using Mathematica). The same figure was
obtained by the author using Matlab. Note that the conjugate
line can be easily constructed using the equilibrium points.
The feed is 1,000 kg/hr of a solution composed of 35 wt %
acetic acid and 65 wt % water. The solvent used to perform
the extraction is pure isopropyl ether with a flow rate equal
to 1,475 kg/hr. We require that the raffinate composition in
acid not exceed 10 wt %. First, we locate the mixing point
and the difference point (see Figure 2 obtained using Matlab).
Then, we step off stages using alternatively the tie lines and
the operating lines until we reach a raffinate composition
lower than 10 wt %. This method is illustrated in Figure 3,
obtained using Matlab. A similar figure was obtained by the
author using Mathematica. We find that
5.35 equilibrium stages are required to
achieve 10 wt % of acid in the raffinate.
Feed The Mathematica notebooks and Matlab
location programs are available from the author
- upon request or from the Mathematica
Information Center[41 and Matlab File
- Exchange Center.[s]

Problem Statement
Consider a binary mixture composed
of benzene and toluene. Assume a con-
stant relative volatility equal to 2.45. Use

4 Figure 2. Mixing and operating
points obtained using Matlab.

Chemical Engineering Education





point -0 60 -40 -20

0 20 40 60 80 100
wt. frac. water

the McCabe and Thiele graphical approach
to compute the number of equilibrium stages
required. Assume feed, bottom, and distillate
mole fractions are equal to 0.5, 0.1, and 0.9
mole % benzene, respectively. Take a reflux
ratio 1.5 times greater than the minimum
reflux ratio.
We want to separate a binary ideal mixture
formed of benzene and toluene. The relative
volatility in this ideal case is the ratio of the
vapor pressures of benzene and toluene. A
straightforward calculation shows that this
mixture's relative volatility varies only be-
tween 2.35 and 2.6 for a benzene mole frac-
tion ranging from 0 to 1. Thus, as a simplify-
ing assumption, we take an average value of
2.45. The feed is a two-phase mixture with a
feed quality equal to 0.85. The distillate, feed,
and bottom mole fractions are 0.9, 0.5, and
0.1, respectively. The reflux ratio is taken to
be 1.514, which is approximately 1.5 times
larger than the minimum reflux ratio. To obtain t
reflux ratio, we require that the two operating li
line, and the equilibrium curve intersect, as sho
4-which was obtained using Mathematica. Th
the McCabe and Thiele Diagram (see Figure 5
obtained using Matlab). A similar figure was ob
author using Mathematica. We conclude that


he minimum
nes, the feed
wn in Figure
ien, we draw
[next page],
stained by the
the required


S rectifying
t 0.6 operating line

S0.4 feed line

S 0.2
operating line

0.0 0.2 0.4 0.6 0.8 1.0

benzene liquid mole fraction (x)

Figure 4. Finding the minimum reflux ratio using Mathematica

Hunter and Nash diagram obtained using Matlab.

number of theoretical plates, to achieve product and bottom
specifications, equals nine. The Mathematica notebooks and
Matlab programs are available from the author upon request
or at the Mathematica Information Center[6] and the Matlab
File Exchange Center." The author brings to the reader's at-
tention that a program to determine the number of equilibrium
stages using the Graphical User Interface (GUI) of Matlab is
available.[8] This GUI program, written by Claudio Gelmi,
was inspired by the earlier code of Housam Binous.

Problem Statement
Use the new dynamic capabilities of Mathematica to
prepare a demonstration where parameters such as relative
volatility, feed composition, and solvent and feed flow rates
... can be manipulated by sliders to study their impact on
the number of equilibrium stages.
The output of Manipulate, anew function available in the
new version of Mathematica (version 6.0), is an interactive
object containing sliders. The output is not just a static
result, it is an interactive program that allows the user to
specify several selected simulation parameters using the
sliders. The program then performs the computation and
displays the result, usually in the form of a plot or a table.
The slider is a control object, which can be dragged by the
user in order to set a specified value of one parameter. The
author has modified his previous program using Math-

Vol. 42, No. 2, Spring 2008

9 0 - - - - - - - ---- - - - - ---- - - - - -!

9 80 -- --------------------------- -----------------------------
I 70 -- --------------. --- --- - - - - ---- ------

g 60 -
S 50--- Operating t e
lines lines


-10 ''-----
-60 -40 -20 0 20 40 60 80 100
wt. frac. water

ematica (version 5.2) to take advantage of this new feature.
Figure 6 shows how the liquid-liquid extraction static simu-
lation has been modified into an interactive program where
one can change the solvent and feed flow rates, the raffinate

1 1 1 1 1 t





.5 0.5-


I 9 7

benzene liquid mole fraction (x)
Figure 5. McCabe and Thiele Diagram obtained using Matlab.

acetic acid composition in feed 0 35
feed flow rate 1000
solvent flow rate 0 - 1600
raffmate specification I 12.22
show difference point Q

3 stages
acetic acid




-100 -50. - 50 10oo a


Figure 6. Liquid-Liquid extraction using the Manipulate command.

specification, and the acetic acid composition in the feed.
Figure 7 presents the simulation where sliders have been set
up for feed quality, feed composition, distillate and bottom
specifications, and relative volatility. These programs are
available, among hundreds of demonstra-
tions made with Manipulate, at the Wolfram
Demonstration Project.[911] In both cases the
- program displays the number of equilib-
rium stages.


Teaching unit operations requires pre-
senting to undergraduate students graphical
methods such as the McCabe and Thiele or
the Hunter and Nash model. These methods
allow for the determination of the number
of equilibrium stages for liquid-liquid
extraction, distillation and absorption,
and stripping problems. With powerful
computer software such as Mathematica
and Matlab, chemical engineering facul-
1 ties can show readily how to compute the
number of equilibrium stages for these
- classic junior- or senior-level problems.
The author uses this opportunity not only
to introduce students to separation science
but also to convince them that Mathematica and
Matlab can be applied to many other interesting
chemical engineering and applied mathematics


In this study, we show how Mathematica and
Matlab can be used to solve problems that previ-
ously required tedious numerical and graphical
techniques. First, we present the extraction of
acetic acid from water using isopropyl ether.
The graphical method, derived by Hunter and
Nash, is used to obtain the number of equilib-
rium stages for a specific raffinate purity. Next,
the McCabe-Thiele method is employed to give
the number of equilibrium stages for a binary
distillation problem. These classic problems
are junior- and senior-level study material at
the National Institute of Applied Sciences in
Tunis. Students excel in these types of problems
despite the fact that it is their first experience
using Mathematica and Matlab.

Chemical Engineering Education

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

0.2 0.4 0.6 0.8 1.0

Figure 7. Distillation using the Manipulate command.

relative I.iii
distillate specification a
bottom specification
feed composition
feed quality --

number of stages = 8

Vol. 42, No. 2, Spring 2008

1. Wankat, PC., Equilibrium Staged Separations, Prentice Hall, Engle-
wood Cliffs, N.J. (1988) (example 18-2, pp. 595 and example 18-3,
pp. 609)
2. Hunter, T.G., and A.W. Nash, J. Soc. Chem. Ind., 53 (1934)
3. Kinney, G.E, Ind. Eng. Chem., 34, 1102 (1942)
5. objectId=13673&objectType=FILE>
7. objectId=4472&objectType=file>
8. objectId=10387&objectType=file>
9. calMethod/>
10. WaterUsingIsopropylEther/>
11. 1

MR! t classroom
---- --- s_____________________________________




United Arab Emirates University * Al-Ain, U.A.E.

Before computers, predictions of physical properties
relied on graphical methods, correlations, and simple
analytical models. Advances in molecular thermody-
namics, statistical mechanics, and computer technology have
changed this scenario forever. Thermodynamic models that
take many details at molecular level into account are now
available for several types of mixtures. Complexity usually
prevents full derivations of these models in undergraduate
classrooms, but it is possible to sketch their major assumptions
and discuss how they translate into model capabilities and
limitations. With this sort of background, students can apply
these models to solve interesting computer-based chemical
engineering thermodynamics problems.
There are different approaches to using these models in un-
dergraduate courses. A possibility is to ask students to program
the models they need, requiring many hours of development
and debugging. Another approach is to use professional soft-
ware such as ASPEN, HYSYS, or Simulis Thermodynamics,
in which students select the components, physical property
package, and type of calculation, and get results immediately.
They may be left, however, with little understanding of the
steps involved in a phase or chemical equilibrium calculation
and there is little or no access to the code-frustrating curious
students. An intermediate approach is to use open software

for use in software like Matlab, Mathcad, or Excel, relieving
students of the burden of writing long programs, yet enabling
them to recombine parts of the code into new applications.
Many recent editions of textbooks on chemical engineer-
ing thermodynamics and related subjects provide computer
programs as supplementary material (e.g., Smith, et al.,[11
Sandler,[2] Elliot and Lira,[3] Koretsky,[41 Kyle,[s] and Cutlip
and Shacham[6]). These programs often run in professional
software such as Matlab, Mathcad, or Excel, or as stand-alone
software, such as the well-designed ThermoSolver71 package
that accompanies Koretsky's book.[41 Another stand-alone
software freely available is the VLE-Java program,'81 which
performs phase equilibrium calculations for binary mixtures

Marcelo Castier obtained his B.Sc. (1981)
and M.Sc. (1985) degrees at the Federal Uni-
versity of Rio de Janeiro (UFRJ), Brazil, and
his Ph.D. (1988) at the Technical University of
Denmark. He joined the United Arab Emirates
University faculty in 2006. Marcelo has super-
vised or co-supervised 20 M.Sc. dissertations
and five D.Sc. tigi and authored more than 60
papers in peer-reviewed journals. His teach-
ing and research focus on thermodynamics
and process design.

� Copyright ChE Division of ASEE 2008

Chemical Engineering Education

using five different thermodynamic models.
An additional aspect, not to be neglected, is cost. Educa-
tional versions of professional software are available and
affordable to many institutions and/or individuals, but this
is not always the case-especially in developing countries.
Availability and ease of use have made Excel a platform of
choice for educational engineering software and, for example,
its use in teaching chemical process design and integration
has been recently discussed.[91 Actually, Excel allows different
levels of programming. Developers can implement their mod-
els in Visual Basic for Applications (VBA) as functions that
users can easily call from the spreadsheet. For example, long
calculations such as those of activity and fugacity coefficients
and residual and excess properties can be programmed in VBA
and made available as spreadsheet functions that students can
use to develop procedures for calculations such as bubble
and dew points and flashes, without extensive knowledge of
programming languages.
Elliot and Lira 31 followed this type of approach and de-
veloped excellent Excel spreadsheets freely available on the
Internet. Some of the newest models, however, are not yet
available in their spreadsheets. Another limitation is that some
of the models are implemented for binary mixtures only or
for mixtures with up to five components. Therefore, even
though the Elliot and Lira spreadsheets are an outstanding
educational tool, improvements are possible.
This work presents a new computational package, XSEOS,
primarily intended for use in undergraduate courses but which
may also be useful for graduate courses and research. XSEOS

Thermodynamic Models and Properties Currently Available in XSEOS
GE models Equations of state
Models Margules 2-, 3-, and 4- suffix* van der Waals
Regular solution theory Redlich-Kwong
Flory-Huggins Soave-Redlich-Kwong (SRK)
Wilson Peng-Robinson
TK-Wilson Stryjek-Vera
NRTL Predictive SRK (PSRK)
UNIQUAC Mattedi-Tavares-Castier
Modified UNIFAC
Properties gE hE sE E P 2P P
RT'RT' R R' )T, ap 3
larlny aKln ln
dnTy a m I.y f1ny
* T i n n o, ap 'n
Sv ,n, , ln T,P,nn

a J /TI ,P,n , - P x x rl,

hR sR c p}
RT' R ' R dT

* The implemented Margules models work for binary mixtures only. All other models
currently available in XSEOS work with any number of components.
Vol. 42, No. 2, Spring 2008

-Excess Gibbs Free Energy Models and Equations of State
-is a freely available program with many traditional and
modern thermodynamic models. Moreover, XSEOS is an
expandable platform with open source code that will hopefully
contribute to the exchange of experiences in the teaching of
chemical engineering thermodynamics.


The underlying concept in XSEOS is that students should
have easy access to calculations using modem thermodynamic
models to become aware of their existence and learn how to
use them. The calculation experience, however, should not be
limited to getting results from ready-to-use programs. Instead,
students should engage in developing calculation procedures
but not in long program development. For example, students
can implement a bubble point algorithm using an Excel
spreadsheet, and then use the functions available in XSEOS to
compute the activity or fugacity coefficients required by their
calculations. The XSEOS add-in does not contain ready-to-use
VBA procedures for chemical equilibrium, flash, dew, and
bubble point calculations, but XSEOS provides the physical
properties required by these calculations. Furthermore, the
XSEOS add-in does not contain VBA functions for ideal gas
and ideal solution properties, as it is simple to program them
in a spreadsheet and their implementation is a good exercise
for students.
One of the major goals of XSEOS is to provide an environ-
ment where students can rapidly develop and test calculation
procedures and compare the results of different models. Because

ease of use was the major goal, the computer
codes are not as efficient as they could have
been if execution speed was the top priority.
Nonetheless, speed of execution was never a
limitation when XSEOS was tested in under-
graduate and graduate courses at the United
Arab Emirates University (UAEU), where
students used the package in laptop computers
to solve classroom and homework problems
and develop course projects.
Table 1 presents the models and properties
currently available in the program. In all
cases, with exception of the Margules model,
users can perform calculations with any
number of components, only constrained by
Excel, the operating system, and computer
limits. The core procedures for all thermo-
dynamic models were automatically written
in VBA using Thermath,t1�1 a program for the
implementation of thermodynamics models
based on Mathematica. They essentially
implement formulas for many physical prop-
erties derived from a given thermodynamic
model. The procedures that implement equa-

tions of state also need a root-finding numerical method to
determine molar volumes in the liquid or vapor phases: the
Toplis, et al.,[11] method was used because it is applicable to
cubic and noncubic equations of state. These procedures are
not used directly from the spreadsheet, as front-end proce-
dures with more user-friendly calling protocols have been
developed manually. The manual distributed with the program
lists the procedures and explains how to use them.

This section presents two sample calculations. In the figures
that support this discussion, cell formats are simple. The sample
spreadsheet distributed with XSEOS uses colors consistently
to indicate cells with specified and calculated values.
Bubble pressures of the mixture methanol(1) +
water(2) at 333.15 K
The objective of this example is to compute the bubble pres-
sure of the mixture methanol(l) + water(2) at 333.15 K for
several liquid phase compositions. Assuming ideal gas phase
behavior, neglecting the Poynting correction and the fugacity
coefficient at saturation, the total pressure (P) is given by:
P = x11P"t + x2,yP2t (1)
where x,, -y, and P,"t represent the mole fraction, activity
coefficient, and vapor pressure of component i. Activity
coefficients will be calculated using the UNIQUAC model.
Figure l(a) shows the spreadsheet before the beginning of
calculations, with entries for the universal gas constant (in
J/mol), temperature, vapor pressures of methanol and water,
and UNIQUAC r, q, and binary interaction parameters (a).
Cell C10, which represents x,, is programmed as 1-B 10 (i.e.,
1-x1) and, whenever the value of x1 changes, the corresponding
x, value is automatically recomputed. XSEOS has a function
named uniquac that takes the universal gas constant, tempera-
ture, mole fractions, and UNIQUAC parameters as inputs to
compute the logarithms of activity coefficients as outputs. This
function, as well as many others in XSEOS, returns more than
one output value. Functions of this type in Excel are called
array functions. To use an array function, the user must mark
the empty spreadsheet cells that will receive the output before

typing the function call. In Fig. l(b), cells D10 and E10 are
marked to receive the values of In y and y2, and the function
call is in preparation. In Fig. l(c) the calling statement of
function uniquac is ready but has not been executed yet. Ex-
ecution occurs by pressing the keys CTRL+SHIFT+ENTER
simultaneously. Figure l(d) shows the results of this action
and Fig. 1(e) shows the set of results for the row. In this figure,
cells F10 and G10 were calculated by taking the exponential
of cells D10 and E10, cell H10 implements Eq. (1), and cells
110 and J10 implement:

x y Pat
Y, - (2)

Having computed the results for the first liquid phase
composition, it is simple to compute for a series of composi-
tions. The value of cell Bli in Fig. l(f) (the value of x1 in
the second point of the composition series) is defined as the
value of cell B10 (the value of x1 in the first point of the
composition series) plus a step size, taken here as 0.25. One
can then mark cells C10 to J10 and drag the Fill Handle (the
small black square that appears in the bottom right corner of
the marked region) to row 11. All the values, from x, to y, are
automatically recalculated. By now marking cells B 11 to J11
and dragging the Fill Handle to lower rows, results from x1
to y, for additional compositions are computed. Figure l(f)
shows the results of these operations that can be used, for
example, to prepare a Pxy diagram using the plotting facili-
ties available in Excel.

Flash calculation by direct minimization
of the Gibbs function
Minimization of the Gibbs function for a system with speci-
fied values of temperature, pressure, and initial amounts of
each component is a fundamental criterion for thermodynamic
equilibrium. In most undergraduate textbooks, however, the
most common numerical approach is to solve the isofugac-
ity equations together with the mass balances, often after
considerable algebraic rearrangement. A flash calculation by
minimization of the Gibbs function is interesting because it
illustrates the direct application of a fundamental criterion in
an actual computation.

I E. ': I E F H I
I methanol(1)+water(21
R T(K)
-- : 1
j r 1 -41 I 1:1
Sq 14-I 14
: a(lJ (J mool) 1:1 - P1sat(kPa) 4- 5i:
7 -":i.; I 0 P2sat (kPa) l 'U.-1

9 x1 x2 Ingamal Ingama2 gamal gama2 P (kPa) y1 y2
10 u I
Figure 1 a-f: Bubble point calculations using the UNIQUAC model. (a) Spreadsheet before the beginning of calculations.

Chemical Engineering Education

S I *: . I E ' *: H
1 methanol(1)+water(2)
2 R T(K)
3 I I-I * 31 1
4 r 14 -I i i :
5 q I - I
6 a(I.j) (Jmol) : I- Pisat (kPa) :4 -,.2
7 :': I P2sat(kPa) I J' : 33
9 1 x2 Ingamal Ingama2 gamal gama2 P (kPa) yl y2
10 ':1 I r. r'
(b) The user must mark the cells for ln-y, and ln-y2 before typing the call of function UNIQUAC.
I E | . I E - I I
1 methanol(1)+water(2)
2 R T(K)
3 1
4 r i - I 1:1
5 q 14 1
6 aQ(.j) (J moo ) - I' Plsat (kPa) ~4 il.
7 "I I C P2sat (kP3) 1
9 xl i2 In2amal Ingama2 gamal gama2 P (kPal yl y2
10 ____ r -in, - ri- r.-r r,: r :: i:- r: f-i
(c) UNIQUAC function call.
E : E F 'H J
1 methanol(,l+water(2)
2 R T(K)
3 - I-I 1f
4 r I -1 1 1 '
5 q I - , 1
6 a(l.j (J mof) II .- Plsat(kPa) -4i.:
7 ' : il . P2sat(kPa) I :
9 A-1 x2 Ingamal Ingama2 gamal gama2 P (kPal yl y2
10 i I ii . - i 1111
(d) Numerical values after the UNIQUAC function call.
1 methanol(1)+water(2)
2 R T(K)
3 -I 114 II-
4 r I 3 II ll 1 '
5 q I-I -1
_6 aI.j) (J mol 11 I- Plsat (kPa) -i -1.'
7 9 :.; I 1: P2sat(kPa) I .'::
9 xl x2 Ingamal Ingama2 gamal gama2 P (kPa) yl y2
10 0 1 0 867 0.000 2.380 1 000 19.953 0 1
(e) Set of results for the specified liquid phase composition.
1 methanol(1)+water(2)
2 R T(K)
3 8.314 333.15
4 r 1.4311 0.92
5 q 1432 1.4
6 a(l I(J/moo 0 -1777 Plsat(kPa) 84562
7 2981 0 P2sat (kPa) 19953
9 xi x2 Ingamal Ingama2 gamal gama2 P (kPa) yl y2
10 0 1 0.867 0.000 2380 1 000 19953 0 1
11 0 25 075 0.324 0.067 1 383 1 069 45.232179 0.6461642 3538358
12 05 05 0.109 0.191 1 115 1210 59.215951 0.7960597 02039403
13 0.75 0.25 0.022 0.331 1.022 1.393 71.776916 0.9031892 0.0968108
14 1 0 0.000 0.478 1.000 1.612 84.562 1 0
Cf) Complete set of results.
Vol. 42, No. 2, Spring 2008 77

The objective of this example is to solve an isothermal n
flash of a ternary mixture of n-hexane(1) + n-octane(2) + n- E
decane(3) using the Peng-Robinson equation of state by direct e
minimization of the Gibbs function. Figure 2(a) presents the C
information required to formulate the problem, i.e., the values a
of critical pressures and temperatures, acentric factors, binary c
interaction parameters (assumed equal to zero), temperature P
and pressure at equilibrium and the global number of moles o
of each substance in the system. The Gibbs function (G) of a p
system with two phases is: S

G = J nlp, = n p -,te (T,P)+RTIn x ) = g
j= 1= J= 1=1 y P (
S2 c (
nl(p '-e (T,P )-RTinP,)+RT nlJn i(xl 1lP) (3) (
1=1 J=- 1=1 tl

where n X, x , , and 4l represent the number of moles,
j lj t
mole fraction, chemical potential, and fugacity coefficient
of component i in phase j. The symbols c, T, and P0 denote
the number of components, the temperature, and a reference
pressure, respectively. The superscripts ig and pure refer to
the ideal gas state and to a pure substance, respectively. From
Eq. (3), it follows that:

- n 1n n (p:g (TP�)-RTlnP�I)
AG 1(2 c Zn *RTlnPc
RT RT iDpu O 0)1

n in( ., P) (4) f
J=l 1=1 o
It can be shown that the minimum of RT given by Eq. (4)
corresponds to the phase equilibrium condition. Figure 2(b)
shows the implementation of Eq. (4) with all the required
intermediate steps. The numbers of moles of each component 1
in the vapor phase (cells B16, C16, and D16) are taken as S
independent variables in the minimization problem, and the r
values in these cells in Figure 2(b) are just initial guesses. The c

1 n-C6(1) n-C8(2) n-C10(3)
2 Tc(K) :U37 : :3 1l31
3 Pc(bar) Il:* I i , l
4 om ega II -'.Il I ." I I) -I: -:'i
5 kij 11 I1: 1 :1. 1:1
6 ij iu u 1 :1 0 1:1
7 I 113 El E I-I I-

9 R (bar.cm3 (mol.K)) 3 1
10 Temperature (K) - 5:
11 Pressure (bar) -1 -
13 Moles n-C6(1) n-C8(2) n-C10(3) Total
14 Global -4 1II J-I L -11J
Figures 2: Flash calculation of a ternary mixture using
the Peng-Robinson equation of state. (a) Spreadsheet before the
beginning of calculations.

lumbers of moles in the liquid phase (cells B15, C15, and
D15) are calculated from the mass balances, i.e., by differ-
cnce with respect to the specified total amounts (cells B 14,
14, and D14). The mole fraction cells, from B19 to D21,
ire computed using the values present in the mole number
ellss. Two array functions, prlnphil and prlnphiv, use the
Peng-Robinson equation of state to compute the logarithms
)f the fugacity coefficients in the liquid and in the vapor
)hases, respectively. Please refer to the first section under
Sample Calculations for details on the use of array functions
n Excel. The arguments in these functions are the universal
gas constant, temperature, pressure, phase mole fractions
either liquid or vapor), and equation of state parameters
cells B2 to D7). The additional cells in the spreadsheet
B28 to D29, B32, and B33) represent the contribution of
he liquid and vapor phases in the evaluation of Eq. (4). Cell
334 contains the cell to be minimized. Excel Solver is used
o minimize cell B34 by modifying the values of cells B 16,
16, and D16, as shown in Fig. 2(b). Figure 2(c) shows the
spreadsheet after problem solution. By comparing Figs. 2(b)
md 2(c), observe that the changes made by Excel Solver in the
apor mole numbers (cells B16, C16, and D16) propagate to
he number of moles in the liquid phase, mole fractions, and all
otherr physical properties. An interesting point to discuss in the
classroom is that cells B28 and B29, C28 and C29, and D28 and
D29 are pairwise equal because they are the natural logarithms
f fugacities, i.e., students can observe the isofugacity criterion
or phase equilibrium appearing naturally from a numerical, as
opposedd to analytical, formulation.

A preliminary version of the program, with different instal-
ation procedure but similar functionality, was used during the
Spring of 2007 in the graduate course of Fluid Phase Equilib-
ia (four students) and in two sections of the undergraduate
;ourse of Chemical Engineering Thermodynamics (about 25
students) at the UAEU. The current version was used in
the only section of Chemical Engineering Thermodynam-
ics (18 students) taught in the Fall of 2007.
Because experience with XSEOS in graduate courses
is limited, the discussion focuses on the undergraduate
course of Chemical Engineering Thermodynamics at the
UAEU. The first half of this course consists of a review
of the first and second laws of thermodynamics followed
by a discussion about free energies, residual and excess
properties, and fugacity calculations. The second half
of the course focuses on formulating and solving phase
equilibrium and chemical equilibrium problems. Students
who take this course are usually familiar with using Excel
to program formulas and prepare plots.
Use of the program consisted of two types of activi-
ties related to phase equilibrium and, to a lesser extent,
chemical equilibrium calculations: (a) instructor-guided
Chemical Engineering Education

classroom solution of problems with each student working
on his/her own laptop computer, and (b) development of a
course project in groups of two or three students. These activi-
ties roughly took place during the final third of the course.
Table 2 (next page) presents some of the projects students
developed using XSEOS. Intrinsic numerical procedures
available in Excel, such as Goal Seek and Solver, were used
in these projects, but instructors and students willing to de-
velop Newton-Raphson-based calculation procedures will
find the analytical derivatives required by many problems
already implemented in the package (Table 1).
Student feedback about the preliminary version of XSEOS
was informal. A formal anonymous survey about the current
version was answered by 16 out of the 18 students who took
the undergraduate Chemical Engineering Thermodynamics
course in the Fall of 2007. Students should "strongly dis-
agree" (1 point), "disagree" (2 points), "be neutral" (3 points),
"agree" (4 points), or "strongly agree" (5 points) with each
of seven statements presented to them.
Table 3 (next page) shows the statements and the cor-
responding average points. The first two statements were
intended to estimate the level of understanding acquired
by using the program. They originated scattered opinions.
Because the survey was anonymous, it was not possible to

13 Moles n-C6(1) n-C8(2) n-C10(3) Total
14 Global 40 30 30 100 000
15 Liquid 17.206 20.436 25.613 63.255
16 Vapor 22.794 9.564 4.387 36745
18 Mole fractions n-C6(1) n-C8(2) n-C10(3)
-- . .............. M o te fre e ,!n ................................................,. .........................................
19 Global 0.400 0.300 0.300
20 Liquid 0.272 0.323 0.405
21 Vapor 0.620 0.260 0.119
23 In phi n-C6(1) n-C8(2) n-C10(3)
24 Liquid 0.743 -0.365 -1 438
25 Vapor -0.082 -0.149 -0.216
27 In x( +In phi() + InP n-C6(1) n-C8(2) n-C10(3)
28 Liquid 0.945 0.009 -0.838
29 Vapor 0.945 0009 -0.838
31 delta G/(R)
32 Liquid -5.009
33 Vapor 17.952
34 Global 12.943
Figure 2 (c). Spreadsheet with the problem solution.

pinpoint the reason, but a possible explanation is that students
who led their project groups developed a deeper understanding
of the methods and calculations. Statement 3 tried to gauge the
reading and use of the pro-

13 Moles n-C6(11 n-C8(2) n-C10(3) Total
14 Global -10 i10 I I3l 1 IlI ll
15 L iq u id I - : II:II: I 'I1 I:II:ll: -. - I.III I 1. 1 .1 ii1:i O
16 Vapor I1_ II 10 000 -00 ii00
18 Mole fractions n-C6(1) n-C8(2) n-C10(3)
19 Global 0.400 0.300 0300
20 Liquid 0 -I 0 333 1 0-I1
21 Vapor 11, . - 1-1 -f.I I 1 I -
23 In phi n-C6(1) n-C8(2) n-C10(3)
24 Liquid 0 44 ::* i - 1 411:1
25 Vapor .0 I : .* IJi *-I IF
27 In x(i) +In phi(i) + InP n-C6(1) n-C8(2) n-C10(3)
28 Liquid 0 I 0 0-10 -1 1 i I
29 Vapor '- - 1:11 -0 J'
31 delta G (RT)
32 Liquid -i. Ii I T -rt " B1M I
33 Vapor ':i--l Ei' , n _ rj, , . il _ , .
34 Global "_-,' -" .
37 ... . ' ., -
40 _
41 iI- r
S14 > ~IN Peng-Robinson /
Figure 2 (b). Spreadsheet with initial guess before the minimization.

gram manual. Interestingly,
students giving high grades
in this statement tended to
give high grades in the first
two statements.
Statements 4 and 5 had to
do with ease of installation
in Excel 2003 and 2007,
respectively. In the Spring
of 2007, all students used
Excel 2003 but, in the Fall,
some students had already
migrated to Excel 2007 and
had installation problems.
Statement 6 was intended
to measure the effectiveness
of the sample calculations
provided in the package.
Statement 7 was intended
to assess the level of confi-
dence for solving new prob-
lems and the results suggest
that students are skeptical of
their ability to do so.
In summary, for all state-
ments, average points
ranked between "neutral"
and "agree." Based on this

Vol. 42, No. 2, Spring 2008

Examples of Assignments and Course Projects Solved Using XSEOS
Assignment/Project Thermodynamic Properties Models
Calculation of octanol + water partition coefficients Activity coefficients at infinite dilution UNIFAC
Vapor-liquid equilibrium of amine + water mixtures Activity coefficients UNIQUAC, NRTL
for carbon dioxide absorption
Properties of refrigerants that may replace CFCs Fugacity coefficients, residual enthalpies Cubic EOS
Compositional segregation of mixtures under gravita- Fugacity coefficients Cubic EOS
tional and centrifugal fields
Vapor liquid equilibrium of chlorine + hydrogen chlo- Fugacity coefficients PSRK EOS
ride and nitrosyl chloride + ethyl acetate mixtures
Chemical equilibrium in multireaction system Fugacity coefficients PSRK EOS

tion procedures, and instructional videos are
available at: mcastier/downloads.htm>.
After installation, all functions of the
thermodynamic package become available.
A spreadsheet that uses these functions in ap-
plications such as bubble points, flash calcula-
tions, chemical equilibrium, energy balances,
and speed of sound is also provided. XSEOS
has open source code and is distributed under
the GNU General Public License, version 3.
Therefore, it is an expandable platform and
will hopefully contribute to the exchange of
experiences in the teaching of thermodynam-
ics. XSEOS runs in Excel, which is part of
the Microsoft Office suite available from
Microsoft resellers.


feedback, the author has prepared movies (available on the
Internet) that illustrate how to perform several types of cal-
culations in XSEOS. This gives students the opportunity to
review the calculation steps when needed. Furthermore, in
future versions of the Chemical Engineering Thermodynamics
course, XSEOS will be used not only for phase and chemical
equilibrium calculations but also during the first half of the
course. The residual and excess functions available in the
package allow the solution of many problems related to the
first and second laws, such as the design of heat exchangers,
turbines, compressors, and expansion valves among many
others. This will give students more time and opportunities
to use and understand the thermodynamic models available
in the program.


XSEOS is an Excel add-in with approximately 20,000
lines of VBA code at the time of its first public release. The
Excel add-in, a sample spreadsheet, a manual with installa-

Areas for collaboration can be broadly organized around
three issues: expandability, usability, and portability.
Given the large number of thermodynamic models avail-
able and their wide range of applications, the set of models
currently available in XSEOS reflects an arbitrary choice
based on the wide use of some models and on the personal
experience of the author with some others.
Many extensions can be envisioned. The most direct is to
include additional models, but there are classes of models
more immediately necessary. Among these are models for
electrolyte solutions, either excess Gibbs free energy (GE)
models or equations of state (EOS), and quantum mechan-
ics-based models, such as COSMO or one of its variations,
that may eventually replace conventional group contribution
models for predictive phase equilibrium calculations. The
creation of interfaces between XSEOS and external parameter
databases for the models already available in XSEOS would
be a useful extension to the package.

Chemical Engineering Education

Opinion Survey of Undergraduate Students of Chemical Engineering
Thermodynamics, Fall 2007, United Arab Emirates University
Point scale: "strongly disagree" (1 point), "disagree" (2 points),
"neutral" pointsts, "agree" pointsts, or "strongly agree" pointst)
Statement Average Points
1. The XSEOS package helped me understand how to perform 34
physical property and equilibrium calculations.
2. I understood the calculations I made using the XSEOS package. 3.7
3. I read or consulted the User's Manual provided with the XSEOS 3.4
4. Installation in Excel 2003 was easy and unproblematic (answer 3
this question only if you used Excel 2003).
5. Installation in Excel 2007 was easy and unproblematic (answer 3.1
this question only if you used Excel 2007).
6. The examples in the Excel spreadsheet are easy to follow. 3.5
7. I would know how to organize the solution of a new problem
in XSEOS, similar but not identical to a problem of the sample 3.2

Examples that illustrate calculations such as the boiling
point of pure substances, bubble points of mixtures, chemi-
cal equilibrium, speed of sound, and residual and excess
properties are provided in the worksheets of the XSEOS
spreadsheet files. User feedback may expand the set of ex-
amples available and contribute to improvements in interface
and documentation.
The use of Excel as a development platform was primar-
ily dictated by convenience because it is widely available as
part of the Microsoft Office suite. The possibility of running
XSEOS in freely available spreadsheets, such as Calc (part
of Openoffice.org), requires porting the VBA code to other
Basic dialects. Free online spreadsheet services, such as
Google's spreadsheet, are currently unable to run XSEOS, but
these services are evolving rapidly and may have the features
required by the package in the future.

An Excel add-in, XSEOS, that implements several excess
Gibbs free energy models and equations of state, has been
developed primarily for undergraduate education, but may
also be useful for graduate education and research. Several
traditional and modern thermodynamic models are avail-
able in the package. Students of the United Arab Emirates
University who used the package could quickly put together
solutions to interesting course projects. XSEOS has open
code and is freely available. This form of distribution will
hopefully encourage other groups to contribute to the project.
The package should be useful for instructors and students of
chemical engineering thermodynamics courses.

The author acknowledges Dr. Silvana Mattedi (Federal
University of Bahia, Brazil) and the students of the Chemical
Engineering Thermodynamics (Spring and Fall, 2007) and
Fluid Phase Equilibria (Spring, 2007) courses at the United
Arab Emirates University for testing the program and sug-
gesting many improvements. The Research Affairs at the UAE
University supported this work (Grant #05-35-07-11/06).

1. Smith, J.M., H.C. van Ness, and M.M. Abbott, Introduction to Chemi-
cal Engineering Thermodynamics, 7th Ed., Mcgraw-Hill, New York
2. Sandler, S.I., ( I...,. . ..i. . 1,, i . ..,,,,.. : Thermodynam-
ics, 4th Ed., Wiley (2006)
3. Elliott, J.R., and C.T. Lira, Introductory Chemical Engineering Ther-
modynamics, Prentice-Hall PTR (1999)
4. Koretsky, M.D., Engineering and Chemical Thermodynamics, Wiley
5. Kyle, B.G., Chemical and Process Thermodynamics, 3rd Ed., Prentice
Hall PTR (1999)
6. Cutlip, M.B., and M. Shacham, Problem Solving in Chemical and
Biochemical Engineering with POLYMATH, TM Excel, and MATLAB�,
2nd Ed., Prentice Hall (2007)
7. Connelly, B., ThermoSolver: An Integrated Educational Thermodynam-
ics Software Program, H.B.S. thesis, Oregon State University (2006)
8. Vaidya, S., , consulted on
Jan. 14, 2008
9. Ferreira, E.C., R. Lima, and R. Salcedo, "Spreadsheets in Chemical
Engineering Education- a Tool in Process Design and Process Integra-
tion, "Int. J. Eng. Ed., 20, 928 (2004)
10. Castier, M., "Automatic Implementation of Thermodynamic Models
Using Computer Algebra," Computers and Chem. Eng., 23, 1229
11. Topliss, R.J., D. Dimitrelis, and J.M. Prausnitz, "Computational Aspects
of Non Cubic Equations of State for Phase Equilibrium Calculations
Effects of Density Dependence Mixing Rules," Computers and Chem.
Eng., 12, 483 (1988) 1

Vol. 42, No. 2, Spring 2008

i] 1= laboratory


Exploring Reaction Kinetics Governing Lactose Conversion

of Dairy Products Within the Undergraduate Laboratory

University of Kentucky * Paducah, KY 42001
Lactose intolerance is a condition suffered by an esti-
mated 50 million Americans. Certain ethnic and racial
populations are more widely affected than others. As
many as 75 percent of all African-American, Jewish, Native
American, and Mexican-American adults, and 90 percent of
Asian-American adults, are lactose intolerant. 1M Some popu-
lations in Africa are completely lactose intolerant, whereas
some northern European populations are unaffected.[2] Why
so? Genetic evidence indicates that lactose intolerance arose
over 5,000 years ago and spread among populations due to
positive selection. Correlations have revealed lactose intoler-
ance is prevalent in geographical areas of extreme climates
and where there have been persistent occurrences of com-
municable diseases affecting cattle.[3]
Lactose, or milk sugar, is a naturally occurring dissacharide
found in dairy products and is normally converted to simpler
sugars in the human digestion process. The lactase enzyme (3-
Galactosidase) hydrolytically cleaves the lactose molecule to
form monosaccharides, galactose, and glucose (see Figure 1).
This enzyme is secreted by cells along the lining of the small
intestine during normal digestion. In some people, this enzyme
is absent or present in reduced concentrations. Interestingly,

most other mammals completely stop producing lactase at
weaning, and are thereafter intolerant of milk. If, during the
human digestion process, lactose is not converted to these
simpler sugars, people may suffer symptoms of bloating,
nausea, cramps, and diarrhea. Hence the term lactose intoler-
ance. Fortunately, it is generally not life-threatening and can
be controlled through proper diet. Lactase-deficient people can
also ingest commercial supplements such as Lactaid and Dairy
Relief with their meal to aid in digestion of dairy products.
This undergraduate laboratory experiment demonstrates the
effect of catalytic action (Dairy Relief) upon skim milk and the
subsequent conversion of lactose to glucose. An inexpensive

Jimmy Smart is an associate professor of
chemical and materials engineering at the
University of Kentucky. He received his B.S.
from Texas A&M and his M.S and Ph.D. from
the University of Texas at Austin, all in chemi-
cal engineering. He has more than 20 years
industrial experience with companies such
as IBM and Ashland Chemical. His research
areas include applications of membranes to
purify water supplies and treatment of hazard-
Sous wastes.

� Copyright ChE Division of ASEE 2008

Chemical Engineering Education

Figure 1. Conversion of lactose to monosaccharides.

blood glucose monitoring meter is used to record changes in
glucose concentration over the course of the reaction. Two
kinetic rate methods are offered to calculate reaction rates;
these are the differential method and initial rate method.
Effects of other reaction variables were studied, including
pH, temperature, catalyst concentration, and catalyst accel-
erations/inhibition. A simple kinetic rate model is applied to
demonstrate development of the Arrhenius expression. Fi-
nally, a more appropriate Michaelis-Menten model is applied
to accurately model the complex enzyme kinetics.

This experiment was primarily developed to be incorporated
into a chemical engineering undergraduate unit operations
laboratory (reactor design). Students could be required to
develop reaction kinetics and use them to design/optimize
a batch reactor to manufacture a lactose-free milk product
based upon economic considerations. On the other hand, more
fundamental portions, such as temperature and pH effects,
could be assigned as part of an undergraduate semester proj-
ect in a lecture class dealing with reactor design.
Learning objectives might include determination
of reaction rates, activation energy, optimum pH
environment, catalyst deactivation temperature,
Michaelis-Menten model parameters, and cata- Equipm

lyst loading effects. The simplicity, portability,
and quick variable response of this experiment
also lend themselves well to K-12 audiences and
other outreach activities. For these activities, it is
recommended one omit the study of temperature
effects (due to the inconvenience of transporting
the control bath) and focus upon effects of pH and
catalyst loading. The more advanced Michaelis-

Vol. 42, No. 2, Spring 2008

Menten model might be appropriate for demonstration within
a chemical engineering graduate lecture class. This experi-
ment also has broad appeal to other disciplines, including bio-
medical engineering and food science curriculums.

Chemicals and Supplies
* Individual instrument test strips for glucose monitoring,
$0.60 ea.
* Skim milk, $0.605/L
* Household distilled white vinegar, 5% acidity, $2/L

* Household ammonia cleaning solution, dilute ammonium
hydroxide, $0.87/L
* pH 4.5 - 10.0 pH test strips (Fisher), $0.09 ea
* Dairy Relief lactase tablet (9000 FCC units), $0.06 ea

1. Milk is a complex food containing over 100,000 different
molecular species. Skim milk contains about 87% water,
3.7 - 5.1% lactose, and 0.75% minerals. It has a density
of 1.03 and a viscosity of 2.1 cP @ 20 'C.'
2. Fill the 1,000 ml glass-jacketed reactor with 490 ml of
skim milk. Turn on the magnetic stirrer to a medium,
reproducible setting (about 300 rpm). Set the temperature
control bath to the desired temperature (between 12 and
38 �C) and wait for reactor temperature equilibration.

3. Initial studies can be conducted using the normal pH of
skim milk, which is about 6.8. If runs will be made to
examine effects of pH upon reaction rate, lower the pH of
the milk with vinegar (about 10 ml for every pH unit) or
raise the pH with ammonia cleaning solution (about 5 ml
for every pH unit).

4. Calibrate the glucose meter according to the manufactur-
er's instructions. Once reactor conditions are at steady-
state, measure the concentration of glucose in the skim
milk (mg glucose/dL). Use a small bore pipette to deposit
a single drop of sample mixture on a test strip. Each test
requires about 60 - 75 seconds for total processing time.

5. Grind up two lactase enzyme tablets with a mortar and

Equipment List
lent Manufacturer Cost
glucose monitoring instrument One Touch Basic (John- $60
son & Johnson, Lifescan
I laboratory temperature- NESLab RTE-100 $1,500
glass-jacketed beaker Ace Glass $120
c stirrer with stirrer bar Fisher $200
- TOTAL $1,880

Blood g]

1000 ml

pestle. Wet the powder with 10 ml distilled water to dis-
solve the powder. When ready to begin a reaction run,
add the catalyst/water mixture to the skim milk.

6. If sampling across long periods of time (differential
method of analysis), sample the reaction mixture twice
and average the results. If using the method of initial
rates, sample reaction mixture consecutively over a 10- to
15-minute time period as there is insufficient time to
repeat samples.

7. To start the reaction at a higher glucose concentration,
dissolve 1.0 g reagent glucose into 20 ml of distilled
water and add it to 480 ml of skim milk. This will raise
the reading of the glucose monitoring meter by about 100
mg/dL. Also, reagent-grade lactose can be added to skim
milk to study the effect of disappearance of reactant,
though starting concentrations of lactose in our milk were
not precisely known (reported to be 3.7 - 5.1%).

The conversion rate of lactose in milk with the use of a
lactase catalyst is a function of several variables, including
lactose substrate concentration, lactase catalyst concentration,
temperature, pH, mixing rate, and ion concentration. The
effect of catalyst concentration upon reaction rate is shown
in Figure 2. As expected, reaction rate is accelerated with
increases in catalyst concentration.

0 1 2 3
elapsed time, min

4 5

The activities of many enzymes vary with pH since the ac-
tive sites of the enzyme contain significant acidic and basic
groups. The influence of pH upon the reaction rate of lactose
conversion to glucose is shown in Figure 3. A reduction in pH
favors an increase in production rate until a pH of 4.5, where
catalyst behavior becomes unstable. It has been reported that
lactase in the Lactaid formulation is effective over the pH
range of 3.5 - 8.5, with an optimum near 8.5.Es5 Classically,
initial rate of this reaction would be expected to vary with a
bell-shaped distribution, with lower rates occurring at low and
high pH and a high median rate at some intermediate pH.E6 7]
Optimum pH for crystalline lactase is reported to be 6.6 - 7.7
at 20 'C.E' In this present investigation, however, reaction
rates of lactase with milk appear to improve with decreasing
pH-down to a pH of 5.0. Evidently, the Dairy Relief lactase
formulation includes buffering agents to allow the lactase to
operate in a more acidic environment, similar to that found
within the stomach. At a pH of 4.5 (as measured by pH paper),
the enzyme initially shows reduced efficiency. Finally after
about 3/4 hour, it begins to behave erratically. Since the pH
of stomach contents is commonly reported to be in the range
of 2 - 4, this would seemingly be a problem for those people
taking lactase to address lactose intolerance issues. The pH
of the distal stomach contents, however, does not fall below
a pH of 5 until some 60 - 75 minutes after the ingestion of a




500 -

- 450 o
o 400 -

, 350
o 300


8 200 -


100 - . ..

0 1 2 3
elaspsed time, hr

4 5 6

Figure 3. Influence of pH upon reaction rate (500 ml milk,
2 tabs catalyst, 22 C, 300 rpm).
Chemical Engineering Education

Figure 2. Effect of catalyst concentration upon reaction
rate (22 C, 300 rpm, 500 ml skim milk).

meal.[91 According to the pH 5 curve of Figure 3, 75 minutes
would provide time for a conservative conversion of about 1/3
of the lactose contained in a glass of milk. The stomach does
not mix at a rate of 300 rpm, however, but it does operate at
the higher temperature of 37 C (310K).

The constructed pH plot (Figure 3) was based upon labora-
tory data collected over several hours. From this data, a dif-
ferential method of analysis, such as graphical or numerical
differentiation, could be used (though not performed here)
to determine the reaction rate law for each set of experimen-
tal conditions. These longer data-collection time periods,
however, are usually not available or practical in a typical
undergraduate laboratory setting. Therefore, as an alternative,
the method of initial rates can be used to investigate reaction
kinetics. For example, Figure 4 illustrates the effect of tem-
perature upon reaction rate. As an assignment, students were
asked to generate data similar to Figure 4 and determine the
rate constants and order of reaction for conversion of lactose
to glucose across various temperatures. Their first approach
(not the correct one) was to treat the reaction as first order,
in the sense, lactose - products. A mole balance on a liquid
phase batch reactor for the appearance of glucose can be


o 285K (12 OC)
350 a 295K (22 �C)
5 303K (30 oC)
v 310K (37 �C)

E 250
C 0
0 225

" 200
0 V
o 175
U) 150
. 125
0 0




-1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
elaspsed time, min
Figure 4. Use of initial rate method to assess effect of
temperature (500 ml milk, 2 tabs catalyst, 300 rpm).

Vol. 42, No. 2, Spring 2008

written as:

dC=r =kC"
dt g

where r is the reaction rate for the appearance of glucose,
k is the specific rate constant, a is the order of reaction, and
C is the concentration of glucose. Upon integrating Eq. (1),
the final result is:

S (lCO)(1- - CO)
S= (1 go (2)
k (1-a)

Using Excel Solver, a nonlinear regression was performed
on Eq. (2) to solve for the specific rate constant and the order
of reaction. The order of reaction was approximately first or-
der (varied between 0.7 - 0.9 across the temperature range of
12 C - 37 C). Using the values of the specific rate constants
as determined from the nonlinear regression, an Arrhenius
plot was constructed and the activation energy for the reaction
was graphically determined to be 39.1 kJ/mole. Assuming
conversion of lactose to glucose to be a single, irreversible
reaction is unjustifiably simple. As it turns out, however (see
below discussion of Michaelis-Menten kinetics), the lumping
together of all reactions and use of the Arrhenius equation is
a fairly good approximation to an otherwise complex reactive

0 1 2 3 4 5 6 7 8 9 10 11
elaspsed time, min
Figure 5. Use of initial rate method to assess impact of
enzyme inhibition (22 C, 500 ml skim milk,
300 rpm, 2 tabs catalyst).

o 150 units galactose oxidase
A pure skim milk
0 0.2 M NaCI
v 0.1 M galactose

Students were asked to generate data similar to Figure 4 and determine
the rate constants and order of reaction for conversion of lactose to glucose across
various temperatures. Their first approach (not the correct one) was to treat the reaction
as first order, in the sense, lactose -products.

network (several reactions occurring with competing values
of specific rate constants).

The surface of an enzyme contains many polar groups that
are influenced by the surrounding ionic environment. It has
been reported that sodium ions have a strong activating ac-
tion on the lactase reaction.[8 9] It is very likely a person might
use significant quantities of table salt as they consume their
hamburger along with a glass of milk. In this investigation,
(see Figure 5, previous page) sodium chloride was not found
to be an activating agent. At 0.2 M NaC1, the salt acted as
a slight inhibiting agent. Using the initial rate method, the
reaction rate with 0.2 M NaC1 was 2.1 X 10-3 mol/L min. as
compared to a rate of 2.4 X 10" mol/L min. with pure skim
milk. At concentrations of 0.05 M NaC1 and 0.05 M MgSO4
(data not shown), there was no measurable change in the
reaction rate. Other strong inhibitors of the lactase reaction
are reported to be (3- phenylthiogalactoside[101 and heavy
metallic ions,[81 though these were not tested. Also, reported
weak inhibitors of the reaction include some of the sugars,
such as melibiose, galactose, glucose, and sucrose. Accord-
ing to Figure 5, galactose was shown to be a strong reaction
inhibitor. When galactose was added to the reaction mixture
(with no enzyme), the reversible reaction was slightly shifted
to the right to produce higher concentrations of glucose-15
mg/dL vs. a routinely measured 9 mg/dL. This may indicate
a reduction in normally available lactose in the initial reac-
tion mixture of skim milk. Once the enzyme was added to
the reaction mixture, the reaction proceeded at a much lower
reaction rate (0.11 X 10 3 mol/L min vs. 2.4 X 10 3 mol/L
min with pure skim milk).
Results with use of a reaction accelerating agent are also
noted in Figure 5. Galactose oxidase converts any available
galactose and drives the conversion of lactose into glucose at
a slightly higher rate (2.9 X 10 - mol/L min vs. 2.4 X 10 -
mol/L min with pure skim milk).

The mechanism for conversion of lactose in milk to the
products of galactose and glucose has been shown to follow
the simple enzymatic reaction:
S+E k S E
S�E+W k2 P+E (3)

where S is the substrate, E is the enzyme, S * E is the sub-
strate-enzyme complex, W is water, and P are the products. By
writing simple rate laws and invoking the pseudo steady-state
hypothesis, whereby the net rate of formation of the substrate-
enzyme complex is assumed to be zero, the Michaelis-Menten
equation can be expressed as:[l, 12]
kI C C
r- a - S (4)
Cs + K
where - rs is the net rate of disappearance of the substrate, kct
= k, C, C is the concentration of the total system enzyme
concentration, Cs is the concentration of the substrate, and
K = (kOat + k ,)/kl.
Interesting aside: Leonor Michaelis (1875-1945) was father
of the permanent hair wave and Maud Menten (1879-1960)
was one of the first women in Canada to earn a medical
The quantity kcat is called the turnover number of the en-
zyme because it represents the maximum number of substrate
molecules converted to products per active site per unit time,
or the number of times the enzyme "turns over" per unit time.
KM, with units of mol/L, is called the Michaelis constant and
measures the attraction of the enzyme for its substrate. KM
is often called the affinity constant. If we let Vma = kcat CEt,
then the Michaelis-Menten equation takes the final familiar
form of:

rs VmxCs (5)
KM + Cs
where Vmx is the maximum rate of reaction for a given total
enzyme concentration, with units of mol/L sec.
According to the basic rate equation of enzyme kinetics
as shown in Eq. (3), there are three rate constants. Each of
these constants will obey the Arrhenius law and there will
be three activation energies associated with each of the reac-
tions. Sometimes, however, the Arrhenius law will follow a
quite complicated enzyme process that involves several rate
constants.[141 The Arrhenius law is reported to be obeyed for
application of lactase to a variety of substrates over the range
of 0 - 37 �C, with activation energies in the range of 12 - 20
kcal/mol.s15l Initially, the reaction rate increases with tem-
perature and then begins to decrease at higher temperatures.
At much higher temperatures, the complicated molecular
structure of the enzyme begins to unfold and lose its catalytic
properties. This is called thermal denaturation.[16] The point of
thermal denaturation for crystalline lactase is reported to be

Chemical Engineering Education

40 'C.E' As a related example, Sizer171 evaluated the thermal
denaturation of the catalase-hydrogen peroxide system. Ac-
cording to Figure 6, the activity of this catalyst follows an
Arrhenius relationship up to about 53 �C and then follows an
inactivation curve at higher temperatures.
Investigators have found the conversion of lactose to glucose
to follow the Michaelis-Menten relationship. This is true when
k << k 1 and there is thermodynamic equilibrium between the
initial free reactants and the enzyme-substrate complex.
Eq. (5) could be inverted and a Lineweaver-Burk plot
constructed to graphically evaluate the slope of the plot as
KM/Vm and the intercept as I/V mx[1118] This is not helpful,
however, as the reaction rate for the disappearance of the
reactant, - r , is not known.
Amore useful method to evaluate the Michaelis parameters
is to substitute Eq. (5) into Eq. (1) and integrate. Note, for
every mole of reactant lactose disappearing, one mole of
glucose is produced. For the appearance of glucose, the final
result upon rearrangement is:
1 C C -C V
SIln C- - -C go - (6)
t Cgo KMt KM



2.1 -

1.9 -

1.7 '

2.9 3.0 3.1 3.2 3.3 3.4
(1/T) x 103, K1

3.5 3.6 3.7

Figure 6. Thermal denaturation of the catalase-hydrogen
peroxide system (from Sizer, I.W, "Temperature Activation and
Inactivation of the Crystalline Catalase-Hydrogen
Peroxide System").171

Vol. 42, No. 2, Spring 2008

Using data from Figure 3 and plotting terms from Eq. (6),
the slope of the line is 1/KM and the intercept is - Vmax / K (see
Figure 7, next page). From this plot, the Michaelis-Menten
constant, KM, assumes different values at different pH levels
(also will vary with temperature), but Vmax is only a function
of enzyme concentration. According to Table 2, the enzyme
is increasingly attracted to the substrate at lower pH (higher
KM), but Vmax is relatively steady across the pH range (enzyme
concentration was not varied).
The Michaelis-Menten constant, K , for lactose substrate
is reported to be 103 moles/L and for maximal velocity, V,m
to be 3 X 103 pm/ml/min/std cone of enzymei101 (9.0 X 10-
mol/L sec for conditions of this investigation). Another in-
vestigator reports Km and Vmax for crystalline lactase acting
on lactose substrate to be 3.85 X 10 mol/L and 1.9 X 105
mol/L sec, respectively, at 20 'C.[15

In the interest of appealing to high school outreach programs
and funding-challenged college undergraduate departments,
an inexpensive means was sought to monitor the reaction
kinetics associated with conversion of lactose to glucose in
milk. The obvious choice to monitor the reaction would
have been to adopt a standard glucose analyzer (Beck-
man, YSI, etc.) commonly found in research and hospital
laboratories. This complete set-up, however, would cost
over $10,000. Other methods considered were based upon
refractive index, freeze point depression, use of a lactose
probe, chromatography,[191 a colorimetric procedure,2201 a
differential pH technique, 211 and various other wet chem-
istry methods. 22 231 Finally, an inexpensive blood glucose
monitoring meter, commonly used by diabetics to measure
glucose levels in blood, was selected as a candidate for
monitoring lactose conversion in milk.
Glucose monitoring meters are portable medical devices
available from several manufacturers for use by diabetics
as a quick, easy, and inexpensive means to monitor blood
glucose levels. The meters are not recommended by the
manufacturer for testing glucose in solutions other than
blood. Currently, two different technologies that govern
the operation of these meters are: (1) electrochemistry
(amperometry), and (2) reflectance photometry. With
reflectance photometry technology, the test strip for the

Graphical Determination of Michaelis-Menten
Parameters at Various pH (22 �C)
pH K,, mol/L V_, mol/L sec
8.2 1.35 X 10 2.26 X 10

6.8 3.46 X 103 2.63 X 10
6.2 4.39 X 10 2.63 X 10
5.0 12.5 X 103 2.88 x 10



meter contains a combination of glucose oxidase catalyst
and a dye mixture. As a drop of blood is placed on the test
strip, glucose and oxygen react in the presence of the catalyst
to produce gluconic acid and hydrogen peroxide. Hydrogen
peroxide, in turn, with mediation by peroxidase, oxidizes a
dye impregnated in the test strip to produce a blue color. The
meter senses the intensity of this blue color, which is propor-
tional to the glucose concentration of the sample. The method
is based upon Trinder's glucose oxidase method and the two
coupled reactions are called Trinder's reaction.[241 Additional
I .lI..Il . Vi:- :- can be consulted for more information about
bioelectrochemical analytical methods.
The Bayer Ascensia Contour glucose meter (electrochem-
istry technology) was tested and found to be unsuitable for
purposes of these experiments. Next, the Lifescan One-Touch
Basic meter (reflectance photometry) was tested. Range of the
meter is 0 - 600 mg glucose/dL (0 - 33.3 mmol/L). Normal
range of glucose concentrations in blood for fasting humans
is 70 - 110 mg/dL. Operation of the meter involves inserting
a coded test strip within the meter and placing a small sample
drop on the strip. After about 60 seconds, the meter provides
a digital readout of glucose concentration. This meter was
responsive when measuring glucose levels in skim milk across
varied temperature and pH ranges, and was selected for use
in this experimental investigation.

The blood glucose monitoring meter is designed to measure
glucose concentrations in blood, but not necessarily glucose
concentrations in milk. A typical meter measurement of raw
skim milk is 9 -10 mg glucose/dL. The actual range of glucose
in nonfat milk as measured by other sophisticated laboratory
instruments has been reported to be 2.2 - 27.0 mg/dL.[27, 28]
Even though our meter measurement was within this range,
it is not known how accurate the meter is at the lower end of
its range (0 - 600 mg/dL). In an effort to check the bias and
accuracy of the glucose monitoring meter over its entire range,
reagent-grade glucose was added to skim milk to make up
various standard concentrations. According to Figure 8, there
is significant deviation between actual concentration of glu-
cose in skim milk and concentrations measured by the meter.
Also, the meter was unable to reproduce concentrations of
glucose in buffered deionized water solutions. When glucose
was added to bovine blood, meter readings were accurate and
linear. As noted above, the glucose monitoring meter measures
glucose concentrations in blood based upon the result of two
reactions with reagents contained on a standardized test strip
(Trinder's reactions). Blood is a very complex mixture of
numerous compounds, including various acid-base buffers to
control its normal pH within the range of 7.3 - 7.4. It is well
documented that Trinder's reactions are subject to bias by
numerous interfering reagents, such as uric acid, cholesterol,
hemoglobin, ascorbic acid, and maltose.[29 30]

Figure 7. Determination of Michaelis-Menten parameters
for various pH (500 ml milk, 22 C,
2 tabs catalyst, 300 rpm).


d 500

~ /

0) 0

-, / ..*" "

E 00 - /

� / / .../"

E o"

0 /I
O *.....o.... skim milk
2 100 -- delonized water
(0 a bovine blood

0 100 200 300 400 500 600 700 800 900 1000
Actual solution concentration, mg glucose/dL
Figure 8. Calibration of glucose monitoring meter
(Lifescan One-Touch Basic Meter).
Chemical Engineering Education

Skim milk is a very complex mixture, containing many
compounds that may interfere with use of Trinder's reac-
tions to analytically quantify concentrations of glucose. It
is believed matrix interference between glucose and skim
milk solutions contributed to nonlinearities in experimental
meter measurements (see Figure 8). Unfortunately, these
were unable to be resolved. Obvious interference were
investigated, including effects of pH (buffered solutions),
solubility, viscosity, red color, and various ion concentrations.
Glucose concentrations in milk could be linearized with the
transform y = -1.553e + 4 + 2022 Ln (x + 2184), where x
is the actual glucose concentration and y is the meter read-
ing. This approach would be acceptable if all other variables
were to remain relatively steady, such as temperature and pH
(which is the case with use of the meter to monitor glucose
levels in human blood). The purpose of the use of this meter,
however, is to evaluate the effects of changes in operating
variables upon reaction rates in milk mixtures. Therefore,
for use as a student exercise, these matrix interference were
ignored. Unfortunately, during the laboratory experiments,
meter reading data does not correspond to true concentrations
of glucose in milk mixtures.

The precision of the meter was found to be satisfactory for
student testing. Error bars based upon results of 10 samples at
various concentrations are shown in Figure 8 to demonstrate
reproducibility. At the lower range, sample mean was 134.1
mg/dL with a sample standard deviation of 8.2. At the upper
range, sample mean was 341.1 mg/dL with a sample standard
deviation of 6.2. Typical precision can be roughly estimated
to be about + 10%. For laboratory runs occurring across long
periods of time, students were required to test each sample
two times and average the results. When using the initial rate
method (occurring across about 10 minutes), there is insuf-
ficient time to repeat samples. Each test requires about 60 to
75 seconds to perform.

An inexpensive glucose monitoring meter has been shown
as an effective tool for measuring relative rates of reaction for
the conversion of lactose to glucose in skim milk. A number
of variable effects can be studied using the meter, but absolute
numbers associated with variable effects cannot be relied upon
because the meter has proven not to be linear across ranges
of glucose in skim milk. Trends can be studied, however, and
the meter serves as a valuable teaching aid for use by under-
graduates in the chemical engineering laboratory.

a reaction order, dimensionless
CEt total system enzyme concentration, mol/volume
C glucose concentration, mg/dL
Cg initial glucose concentration, mg/dL
C, water concentration, mol/volume

Vol. 42, No. 2, Spring 2008

t time, sec
k specific rate constant, time 1, if a = 1
kt turnover number = k2 C,
rg reaction rate for the appearance of glucose, mol/L
- rs reaction rate for the disappearance of the substrate,
mol/L min
Vmax maximum rate of reaction for a given total enzyme
concentration, mol/L sec
KM Michaelis constant (affinity constant), mol/L

1. American Gastroenterological Association,
2. Flatz, G., "The Genetic Polymorphism of Intestinal Lactase Activity in
Adult Humans. "In The Metabolic Basis of Inherited Disease; Scriver,
C.R. (Ed.); 6th Ed, McGraw-Hill, New York (1989)
3. Bloom, G., and PW Sherman, "Dairying Barriers Affect the Distribu-
tion of Lactose Malabsorption, "Evol. and Human Behav., 26, 301e.1
4. Dairy Science and Technology at the University of Guelph (Canada),

5. Conversation with Bill Chapello, McNeil Consumer & Specialty
Pharmaceuticals (March 23, 2006)
6. Tipton, K.E, and H.B.F Dixon, "Chp 5. Effects of pH on Enzymes," in
Contemporary Enzyme Kinetics and Mechanism, ed. Daniel L. Purich,
Academic Press, NY, 97 (1983)
7. Laidler, K.J., and PS. Bunting, The Chemical Kinetics of Enzyme Ac-
tion, 2nd Ed., Clarendon Press, Oxford (1973)
8. Wallenfels, K., "Section 23. P-Galactosidase (Crystalline)," in Methods
in Enzymology, eds. S.P Colowick and N.O. Kaplan, Academic Press
NY, 5, 212 (1955)
9. Omari, T., and G.P Davidson, "Multipoint Measurement of Intragastric
pH in Healthy Preterm Infants, "Archives ofDisease in Childhood Fetal
and Neonatal Edition, 88, 517 (2003)
10. Hestrin, S., and D.S. Feingold, "Section 29. Hexoside Hydrolases,"
Methods in Enzymology, eds. S.P Colowick, and N.O. Kaplan, Aca-
demic Press, NY, 1, 231 (1955)
11. Fogler, S.H., Elements of Chemical Reaction Engineering, 4th Ed.,
Prentice-Hall, New York, 399 (2006)
12. Michaelis, L., and M.L. Menten, "Kinetics of Invertase Action," Bio-
chemische Zeitschrift, 49, 333 (1913)
14. Laidler, K.J., and B.E Peterman, "Chp 6. Temperature Effects in En-
zyme Kinetics," In Contemporary Enzyme Kinetics and Mechanism,
ed. Daniel L. Purich, Academic Press, NY, 149 (1983)
15. Kuby, S.A., and H.A. Lardy, "Purification and Kinetics of P-D-Galac-
tosidase from Escherichia coli, Strain K-12," J. Am. Chem. Soc., 75,
890 (1953)
16. Shuler, M.L., and E Kargi, Bioprocess Engineering Basic Concepts,
2nd Ed, Upper Saddle River, NJ, Academic Press, 77 (1973)
17. Sizer, I.W., "Temperature Activation and Inactivation of the Crystal-
line Catalase-Hydrogen Peroxide System," J. Biol. Chem., 154, 461
18. Aiba, S., A.E. Humphrey and N.E Millis, Biochemical Engineering,
2nd Ed., Academic Press, New York, 95 (1973)
19. Ivany, J.WG., and E.P Heimer, "Quick Paper Chromatography of
Monosaccharides," J. Chem. Ed., 50(8), 562 (1973)
20. Huggett, A., and D.A. Nixon, i .. ..... Determination of Blood
Glucose, Biochem J., 66, 12 (1957)
21. Luzzana, M., D. Agnelliji,, P Cremonesi, and G. Caramenti, "Enzy-
matic Reactions for the Determination of Sugars in Food Samples
Using the Differential pH Technique,"Analyst, 126, 2149 (2001)
22. Wilding, P, "Review of Methods for the Determination of Glucose,"
BUPA Pathol. Lab., London, UK, ed. A.E. Rapport, Qual. Control
Clin. Chem., Trans. 4th Int. Symp., 1971, Publisher: Huber. Bern,

Switzerland, 254 (1972)
23. U.S. Patent RE29498, "Process for the Enzymatic Determination of
Glucose with a Glucose-0 .I .1 i .- ...I .1 Enzyme System,"
Dec. 20, 1977
24. Trinder, P, "Determination of Glucose in Blood Using Glucose Oxidase
With an Alternative Oxygen Acceptor," Ann. Clin. Biochem., 6, 24
25. Brajter-Toth, A., and J.Q. Chambers (eds.), Electroanalytical Methods
for Biological Materials, Marcel Dekker, NY (2002)
26. Barham, D., and P. Trinder, "An Improved Colour Reagent for the
Determination of Blood Glucose by Oxidase System," Analyst, 97,
142 (1972)

27. Katsu, T., X. Zhang, and G. Rechnitz, "Simultaneous Determination of
Lactose and Glucose in Milk Using Two Working Enzyme Electrodes,"
Talanta, 41(6), 843 (1994)
28. Rajendran, V., and J. Irudayarj, "Detection of Glucose, Galactose,
and Lactose in Milk With a Microdialysis-Coupled Flow Injection
Amperometric Sensor, "J. Dairy Sci., 85, 1357 (2002)
29. U.S. Patent 4350762, ......... .. .... Improved Trinder's Reagent and
Dosing Process for Hydrogen Peroxide From Enzymatic Oxidation of
Metabolic Substrata With the Same," Sept. 21, 1982
30. Lott, J.A., and K. Turner, "Evaluation of Trinder's Glucose Oxidase
Method for Measuring Glucose in Serum and Urine," Clin. Chem.,
21/22, 1754(1975) 1

Chemical Engineering Education


for the
Fall 2008 Graduate Education Issue of

Chemical Engineering Education

Each year, CEE publishes a special fall issue devoted to graduate education.
It includes articles on graduate courses and research in addition to ads
describing university graduate programs.

We invite articles on graduate education and research for our
Fall 2008 issue. If you are interested in contributing, please send us your
manuscript as a pdf file, via e-mail, by the deadline below.

Deadline for manuscript submission is May 15.2008.

Respond to: cee@che.ufl.edu

----- --- s___________________________________________



Arizona State University * Tempe, AZ 85287
Group projects are frequently assigned in chemical
engineering courses to achieve a number of differ-
ent objectives. First, we want to improve students'
understanding of group dynamics so that they can work more
effectively in teams."' Second, a group of students can fre-
quently achieve a greater depth of understanding on a given
topic than a single student working alone. Third, grading a
single group project normally requires less time than grad-
ing four (or more) individual projects. There are many other
advantages to group projects for specific courses, but these
three advantages are nearly universal and apply to any course.
There are also a number of disadvantages or perceived disad-
vantages often cited by either the students or the instructor.
First, it is difficult to determine the workload distribution
among the students in the group-making it a challenge to
give individual grades.[2] Second, some groups are unable to
schedule enough meetings when every group member can
be present. Third, the collecting of the individual pieces of a
project into a single coherent document or presentation can
be difficult and frustrating for some groups.
Despite the disadvantages, group projects are an important
and integral part of the educational experience within the

chemical engineering curriculum. Team projects in an indus-
trial setting, however, are changing because geographically
dispersed teams are becoming more common.[3 4] Often, the
team members can be located in two or more different cities
or countries. Of course the team members will meet at im-
portant times during the project, but much of the day-to-day
work will be completed by communicating over the phone
or Internet (e.g., e-mail, instant messenger). At Arizona State
University (ASU), we recently began using a "wiki" for group
projects in the Introduction to Chemical Engineering: Mass
and Energy Balances course to overcome some of the difficul-
ties associated with traditional (paper) group projects and to

Jeffrey J. Heys is an assistant professor at
Arizona State University. He received his B.S.
in chemical engineering in 1996 from Montana
State University, and his M.S. and Ph.D. from
the University of Colorado at Boulder in 1998
and 2001, respectively. His research area is
computational transport and computational
fluid dynamics in biological systems with an
emphasis on fluid-structure interaction and
multiphase flows.

� Copyright ChE Division of ASEE 2008

Vol. 42, No. 2, Spring 2008

give the students experience in working on a group project
where the group members are not necessarily located in the
same physical location.
The term "wiki" is a Hawaiian word meaning "quick," but
the term is used here to refer to a specific type of Web site.
The definition in this case, taken from Wikipedia ( wikipedia.org>), is that a wiki is a Web site that allows visi-
tors to add, remove, and edit content. It is frequently used as
a collaborative technology for organizing information on Web
sites. One of the most commonly cited examples is Wikipedia,
an online encyclopedia where entries can (normally) be edited
by anyone using a modem browser such as Internet Explorer
(from Microsoft), Firefox (from the Mozilla Foundation), or
Opera (from Opera Software). Wikis are used for collaborative
or group projects for two main reasons: (1) they are easily
modified (you do not need to learn HTML programming)
using any modem browser instead of requiring every group
member to use the same software (how many group projects
have been interrupted by incompatible software versions or
operating systems?), and (2) the changes made are imme-
diately available to other group members. A group project
completed using a wiki results in a Web page, and, since it is
a wiki, that Web page can be edited using the same software
that is used to view it.
Depending on the type of wiki used (see the next paragraph),
a wiki can overcome many of the difficulties given above
that are normally associated with group projects. First, the
computer server that hosts the wiki can store every change
to the individual project Web page, and students can be re-
quired to log in to make any changes. This means that when
grading the wiki, the exact contributions made by each and
every student are available to the instructor. This includes
every change made and when the change was made. Second,
editing the project Web page only requires that a student have
Internet access, so the group does not need to meet face-to-
face as frequently to work on the project. Their discussions
and editing can happen online instead. Third, instead of hav-
ing group members produce individual pieces that are glued
together the night before the project is due, the group project
can ideally be produced over time with each member editing
the contributions of others to produce a more coherent final
document. A few other advantages include
* The instructor always has access to the current state of
the group project while it is being completed.
* Group projects from the past are easily available to
later classesfor their reference.
* Students can be required to edit and/or view other
group projects.

There are basically three options when setting up a wiki
for group projects.
(1) Many colleges and universities have servers and

software in placefor!,.. I ,,, a wiki. For example,
at ASU the Web page allows you to
create a wiki for group projects with a simple click of
a button on the Web page. You only need to give the
wiki a name (e.g., CHE 211 Projects) and the students
can then create and edit their own group project Web
pages on that wiki.
(2) There are a number of companies that host free wiki
Web sites (e.g., ).
(3) Install MediaWiki (), which is
the software behind Wikipedia, on your own computer
or Web server. We used a basic desktop computer
(Dell computer with an Intel Xeon processor) running
Linux (Red Hat Enterprise Linux 4), and the installa-
tion of MediaWiki took about one hour. In hindsight,
we recommend running the Ubuntu or Fedora flavors
of Linux because the one small difficulty we encoun-
tered was specific to RHEL.

Options 1 and 2 are clearly simpler and avoid the need for
a continuously running desktop computer with Linux, but
there are also some important advantages to option (3). First,
running your own copy of MediaWiki provides outstand-
ing flexibility in terms of what is possible to include on the
group project page. For example, we used the "math" add-on
extensively because it provides a straightforward method for
displaying complex mathematical equations on the project
Web page using a syntax that is similar to LaTeX (i.e., this is
equivalent to the equation editor in Microsoft Word). Similar
add-ons include displaying chemical reactions and includ-
ing animations or movies. A second advantage to option (3)
is that it provides a fine level of control over access to the
wiki's Web pages. We chose to require a log-in for editing of
the Web pages, but no log-in was required to view the pages.
This means that students can modify the project of any group
they want, but those changes are logged under their name and
can be "undone" at any time. While the advantages to option
(3) listed so far do not require any programming knowledge
whatsoever to implement, the final advantage to option (3) is
that MediaWiki is largely a collection of PHP files that can be
edited to achieve any desired behavior. Just purchase a PHP
book at the local bookstore and any missing feature or any
desired change can be made by the instructor.
The upper part of the "Main Page" for the wiki used in the
Mass and Energy Balances course is shown in Figure 1 (see
Reference 5). At the top of the page is an introduction explain-
ing the goals of the project and a list of important dates for
the project during the semester. Also on the Main Page, but
not shown in Figure 1, are a list of links to the various group
project pages and some instructions on using the wiki. Near
the upper-right corer in Figure 1 is a link to "Log in/create
account." The wiki was set up so that users were required to
log in to edit any of the Web pages, but account creation was
disabled. Accounts were created for all registered students in
the class using a unique ID. By clicking on the "Log in" link,
Chemical Engineering Education

students could enter their unique ID and have a randomly gen-
erated password e-mailed to their registered e-mail address.
Also note the "edit" links near the top of the page and along
the right edge. Clicking on these links allows the entire page
or subsections to be easily edited.

Clicking on an edit link brings up the editing window that
is similar to a normal word processing window. We chose to
require a log-in before the editing of any pages, and the upper
right corer of the page indicates which user is logged in. The
editing process is similar to using any word processor, and the

File Ed< Viw Histry Bookmarks Tods Hlp 'Ijeffheys
ITT* T hCE E E tp/ haodeas asi.edu khe211wkirdex phManPa � - Googe C

ChE Main Page
211 --

n n Introduction [ed
Mi Welcomto eChE 21 WlPro Tmh goals Pofthisrpre a
Sdeep an rfe m en lopedla of te , hnues and example problems in Che211, and
m betterleanng through app on and analyst.
To achie these goas eryon hs mstcontnbute thedeelopment of anew page(i.e., new bpage)hat
at inks here dcuse a topic from this course, Includes the necessary efinionas, and probably indudes an example proibem. Each page must
0 "Relat changes pnmanly de-l."d by group of 2 to 4 i duas. You am a- required to ,it a page d-wlope by another group, I kep
SUplod le things in m
S al - 1. ALL k ed s a recorded and arched adatabamse,nd
2. any attempts o hack the m or wki serve 11 be punished.
Important Dates [edit]
Oct. 18 Topic selected and our name added to that topics tak
Nov. 9 JI team membr mut ha made an ongna con on to t t the "fir st d a of th wlk mus compiled
D2 1 Al editing must sopad the ks wil be ~ raded.

Figure 1. Upper part of the Main page for the
ChE 211-Mass and Energy Balances wiki.

Fi Efit _w Hitory Boomarks loo
Sporis' Rsearch' Compute' Nems' Maqs ASU' Gats' Chander' HeysFamlyPaqe Lbbau Acles Melire mov.qt
2ji� du pi___ 1c

ChE Nume, 1..I I.,-griCn

Comenns -1
I 1r What is it? e

l l evenly acedd merdals. I th endpo nts calculated, hen te Trapezodal (nT 2poin e Newt Cotes formia) and Smpsn's ole (the
3 -port MeMton LoresomuaJcan beappled. Ie l an d ease or, iussan quadrature ns where the tunmccns are inow
amnayi y ad , t n eculaed at y nly spaced intewas B au ating tte unalon at certna abas , Gaussian quadrature st
a3p mates -he integral

S e negratin a Jncon over anmevl I ca e acc pishidby p adding the ntea irto equal pars.

* " e terf I olbmlads can ,deIerndforafunctonor a gin inteaJ by aplyng Lagraie interpotang polyomis.

Trapezoidal Rule

_- _
Figure 2. An example of a group project report on Numerical
Integration. The figure shows less than 10% of the
final project, but it illustrates a typical result.

Vol. 42, No. 2, Spring 2008

buttons above the editing window allow for the insertion of
objects such as mathematical equations, lines, bold face text,
and links to other Web pages. The "discussion" tab, shown
in Figure 1, is a similar window where group members can
discuss their plans with each other and the instructor can leave
comments for the group.

Clicking on the "history" tab in any window brings up a
page showing a detailed list of the changes that have been
made to the Web page. For example, the history tab for the
main page shows that the page has mostly been modified
only by the instructor, .h . , "It also shows, however, a
student changed the name of a project (the only part of the
Project appearing on the main page) and another student
corrected the instructor's spelling and grammar oopss!).


The group projects from our first semester of using
wikis (Fall 2006), can be found at edu/che211/wiki>. We chose to give the students the
option of using one of the suggested project topics or
proposing their own topic, and >90% of the groups chose
one of the suggested topics. The topics loosely fall into
four different categories.

(1) Advanced topics that are not covered in lecture, but
are presented in the textbook (e.g., commercial pro-
cess simulation packages).

(2) Topics covered in class that students frequently strug-
gle to understand, and the goal is to provide future
classes with an additional reference on this topic (e.g.,
recycle streams).

a (3) Topics covered in other courses that may be useful
to the students in Mass and Energy Balances (e.g.,
numerical ; , ti , ii,.,, i

(4) Popular topics related to the course material (e.g.,
future energy sources).

For category (1) projects, the students typically read
the material in the textbook and then obtained some of
the books and articles referenced by the textbook.[6] For
commercial process simulation packages, company Web
sites also provided important information. Category (2)
projects involved the students presenting course material
in a new perspective that they found more intuitive, and
they often included additional example problems. Some
excellent projects resulted from topics in categories (3)
and (4), but the students often recycled material from other
classes, limiting the amount of new learning. This is not
a limitation of using a wiki, but it is a common difficulty
in all types of group projects. Figure 2 shows the very
beginning of the numerical integration group project as
an example. The entire numerical integration project as
well as the other 19 projects competed in Fall 2006 are
available on the Web site given above.

Based on the results of our first semester of using a wiki
for the group project and on feedback from the students, we
offer a couple suggestions for using this format. First, because
students are often unfamiliar with wikis, it is important to set
early milestones or due dates for parts of the project. For ex-
ample, we required students to visit the Web page and get their
password during the first month of the semester, before they
were prepared to choose a topic. We also required each group
to create a nearly blank page containing only their names
early on so they could get a little experience editing a wiki.
To facilitate this project, a sample page was created in class
so that students could see the process for themselves-which
greatly reduced the level of intimidation. A second suggestion
is to provide students with multiple links to documentation
for the use of wikis in general and MediaWiki in particular.
During the Fall of 2007, a group of students at Arizona State
University created a wiki entitled "How to Create a Wiki-
Project," and this wiki, as well as many other examples, can
be found on the ChE 211 site given above.
Two problems were noted when the group projects were
moved to a wiki format. First, the level of plagiarism appeared
to increase because students found it incredibly easy to cut
and paste from existing Web pages. This problem was identi-
fied early in the semester, and in-class warnings appeared to
reduce the level of abuse. Numerous tools are available (e.g.,
Ephorus) that can be used to detect plagiarism with little ef-
fort. Second, some of the students had extensive experience
in using HTML (thanks to , etc....) and this
knowledge allowed them to introduce specialized features to
the Web pages beyond what is possible using the normal "edit-
ing" features. This is not a problem, except those individuals
would dominate the actual editing of the group's Web page
-reducing the instructor's ability to determine individual
contributions. This difficulty was avoided by requiring stu-
dents entering material for other students to note that they
were doing so in the "discussion" area of each page.

c 10


0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 More
Nllmhar nf Fditc

We have found the wiki format to be useful for projects in
a Mass and Energy Balances course, but this does not mean
that this is a useful format for projects in other courses. For
example, the rigorous formatting requirements of senior
laboratory reports, such as flowsheets, equipment diagrams,
and numerous chemical and mathematical formulas, would
make the use of a wiki difficult. Also, if a project report is
more than 10 pages, the wiki format may not be appropriate
because it requires that the person preparing the report be ac-
tively connected to the Internet during the entire time they are
writing. In summary, we tend to prefer using wikis in larger,
undergraduate courses where they can be an interesting and
useful way for groups of students to prepare a report that is
equivalent to 5-10 pages.

One of the advantages to using a wiki is that each contri-
bution by a student is recorded in a database. The individual
changes may be as small as correcting a spelling mistake or
adding a period, and the changes may be as large as adding
numerous paragraphs to the group report. On average, an indi-
vidual change was equivalent to adding one or two sentences.
In the Fall of 2006, there were 67 students enrolled in the ChE
211 course at ASU, and they completed 20 group projects.
On average, projects received about 61 edits each, and the
average student made about 18 edits or individual changes to
his/her group project Web page. The standard deviation for
the average edits per student, however, was 20, indicating
that the students varied greatly in the number of edits made.
In fact, a few students only made two or three edits, but a
few other students made more than 100 edits. Figure 3 is a
histogram showing the number of students making edits over
different ranges.
This data should not be interpreted as an exact measure
of the distribution of work performed by the various group
members because an "edit" could be a large or small change.
(There have been a number of studies that have tried to
examine work distribution among members of a groups,
and studies on improving group performance.7, 8]) There is
some correlation, however, between the number of edits
and the amount of work done, and we were surprised at the
large distribution. Typically, a group of four would have
one or two individuals making 20 or 30 edits and one or
two individuals making less than 10 edits. This observa-
tion encourages more study on the distribution of work in
group projects and ways to measure that distribution. It
also motivates us to more closely monitor the work that
every individual in the class is doing on the group project
throughout the semester so that students can be alerted
when they are not doing their share of the work. We also
plan to increase the percentage of the final grade that is
tied to the individual's contributions to the group project
from about 25% to 40-50%. Historically, we have used the

Chemical Engineering Education

Figure 3. The number of students (frequency) making
different numbers of edits. The average
number of edits made was 18.



smaller percentage because individual contribution was dif-
ficult to measure, but now that the data is available, we plan
to increase the percentage.

Using a wiki as a medium for group projects has advan-
tages and disadvantages over the traditional oral and paper
mediums. The advantages include
* The ability to continually monitor and measure the
work being done by each group and individual student.
* \,,i,, f ...I , 1,1 methods for archiving the projects
and making them available to future classes.

* Providing the students with experience in working as
part of a virtual or Web-based team.

Disadvantages include:
* The need to invest time iii,, up the wiki (especially
if the instructor elects to install MediaWiki).

* Possibly an increased potentialfor plagiarism.

* Afew students are intimidated by the software.

Based on our experience, the advantages were greater than
the disadvantages, and we plan to continue using the wiki. The
only significant change we plan to make is to more closely
monitor the contributions of individual students throughout

the semester so that we can alert students when they are not
contributing sufficiently to the overall group effort.

Thank you to Luke Olson for showing me the potential of
wikis and helping with the installation of MediaWiki.

1. Chen, G.D., C.Y. Wang, and K.L. Ou, "Using Group Communication to
Monitor Web-based Group Learning, "J. Computer Assisted Learning,
19, 410 (2003)
2. Chen, Y., and H. Lou, "Students' Perceptions of Peer Evaluation:
An Expectancy Perspective," J. Education for Business, 31(1), 91
3. Friedman, T.L., The World is Flat: A Brief History of the Twenty-
First Century, 1st Ed., Farrar Straus and Giroux. viii 488, New York
4. Swisher, K., " 'Wiki' May Alter How Employees Work Together," Wall
Street Journal, 224(20), B1-B2 (2004)
5. Heys, J.J., "ChE211 Wiki Project Webpage," (2006) Available from:

6. Felder, R.M., and R.W Rousseau, Elementary Principles of Chemical
Processes, J. Wiley & Sons, New York (2000)
7. Peterson, E., et al., "Collective Efficacy and Aspects of Shared Mental
Models as Predictors of Performance Over Time in Work Groups,"
Group Processes & Intergroup Relations, 3(3), 296 (2000)
8. Yoon, S.W, "Two Group Development Patterns of Virtual LearningTeams,"
The Quarterly Review of Distance Education, 7(3), 297 (2006) 1

Vol. 42, No. 2, Spring 2008

Random Thoughts...


North Carolina State University

Sheila: Good morning, Reggie-great to have you with us.
I'm Sheila Conner, head of Process Engineering.
Reggie: Nice to meet you.
S: I was really hoping you'djoin our group-I saw your
file and you don't see 3.9 GPAs every day, especially
coming from your university.
R: Thanks. I'm looking forward to using what I learned
S: Well, you'll get plenty of chances to do that here. As
they probably explained to you, we get involved in
almost everything that happens in the plant-design-
ing new processes and products, retrofitting, trouble-
shooting, you name it. How does that sound?
R: Um, good, I think. Ijust took plant design last spring,
so I'm probably more up on that than on that other
S: I see-well, anything you're not sure of, just ask
anybody here. As a matter of fact, there's something
we could use your help on over in hydrides...the ef-
ficiency of one of their packed absorption towers has
been falling for the last week and they can't figure
out what's going on. Go over to Building 293 and
ask for Ben Whitman-he'll fill you in, and then see
if you can figure out anything.
R: OK.

R: Excuse me, are you Ben?
Ben: Yeah-what can I do for you?
R: I'm Reginald Bunthorne. Sheila from Process Engi-
neering sent me ... something about an absorption

B: Oh, yeah. Come into the office, kid, and I'll show
you what we got. OK, here's a GC trace on the
off-gas line from about two weeks ago-this peak
is CMPH, and it's down around 2.5 where it's sup-
posed to be. It started to creep up on us last week,
and here's yesterday's trace-the peak is up to 7,
which means we're absorbing a lot less CMPH than
we're supposed to. Unless we can fix this, we're
going to have to take the process off line and break
down the tower to see what's going on, and a lot of
people across the street will be very unhappy if we
do that. Got any ideas for us, kid?
R: Um ... I think we once used the diffusion equation
and Henry's law -or maybe it was Raoult's law-to
analyze a continuous packed absorption tower. I
could try doing that.
B: Say w Ik '
R: Of course I can only do it if the column is isothermal.
It is, isn't it? If it isn't, I think I'd also have to write
a differential energy balance equation, and that's
farther than we ever went in that course. I can give
it a shot, though-you do have Matlab here, don't

� Copyright ChE Division of ASEE 2008
Chemical Engineering Education

Richard M. Felder is Hoechst Celanese
Professor Emeritus of Chemical Engineering
at North Carolina State University. He is co-
author of Elementary Principles of Chemical
Processes (Wiley, 2005) and numerous
articles on chemical process engineering
and engineering and science education,
and regularly presents workshops on ef-
fective college teaching at campuses and
conferences around the world. Many of his
publications can be seen at edu/felder-public>.

B: (Looks suspiciously at Reggie and says nothing)
R: Let's see-I think I'll also need to know the diffusiv-
ity of--what was that, CPMH?- and the Henry's law
solubility. Do you happen to know what they are?
B: Uh, tell you what, kid-we've got a few ideas we
want to try first, so let's hold off on that stuff for
now. I'll check in with Sheila and tell her we'll call
again if we need you.
R: OK, and don't forget the diffusion coefficient.
B: Trust me, I won't forget it.

S: So I hear you had a session with Ben yesterday. How
do you think it went.
R: Fine-I'm surprised I haven't heard back from
S: Hmm. Well, we've got anotherjob over here I'd like
you to take a look at. It's a distillation column we
need to design for a pretty tough separation-think
you can handle it?
R: No problem-I did a couple of them in mass transfer
... I think we also did one in plant design, but one
of my teammates handled that part.
S: Um... yes ... fine. Here's the folder with the design
specs ... let me know if you need anything else.

S: Yes, Reggie-got something for me on that col-
R: I get that you need eight theoretical stages.
S: What?
R: Eight theoretical stages -here's the McCabe-Thiele
S: Uh .. . how'd you do McCabe-Thiele with nine
components in the feed?
R: I just used two components I could look up data for
in Perry's Handbook and used Raoult's law to come
up with an equilibrium curve and then did McCabe-
S: For a multicomponent system with nine highly polar
R: Well, they never really talked about systems like this
in mass transfer-the professor said that equilibrium
separations were trivial and we spent most of the

course solving differential equations for rate-based
processes ... and I tried finding vapor pressure data
for those other feed compounds but they weren't in
Perry, so I just made some simplifying assumptions.
S: Ah, some simplifying assumptions. OK, why don't
you let me have the file back and we'll take it from
here. Let's see-you know any process control?
R: Yeah, we learned how to calculate transfer functions
for linear systems.
S: But real-time control for nonlinear systems?
R: They said they didn't have time to cover that.
S: What about statistical quality control?
R: Um, no-we had a couple of weeks of statistics in the
unit ops lab ... means and standard deviations and
t-tests and that stuff, but they never really explained
what you do with it.
S: Ever size a pump?
R: No-pumps were in the fluids syllabus, but the prof.
took so long on the Navier Stokes equation that we
never got to them.
S: Know anything about separation process synthesis?
R: Um ... not really.
S: Heat exchanger networks?
R: No-we only did single exchangers.
S: Using overall heat transfer coefficients andlog-mean
temperature differences, right?
R: Uh, yes. We were supposed to look at solving more
complex problems using a simulator, but the prof.
said we needed to learn the fundamentals before
getting into black box simulations and I guess we
never got past the fundamentals.
S: Equipment cost estimation?
R: My design teammate did that part.
S: I see ... OK, to tell you the truth, Reggie, I'm not
sure there's a good fit between your skills and the
kind of things we do around here. I'm going to talk
to Human Resources about finding you a more suit-
able position.
R: All right ... but in the meantime, what should I do
while I'm here?
S: Know how to use a coffee maker?
R: Um . . .

Vol. 42, No. 2, Spring 2008

All of the Random Thoughts columns are now available on the World Wide Web at
http://www.ncsu.edu/effective_teaching and at http://che.ufl.edu/~cee/

i] '1 laboratory


Based on a Transient Response Experiment

Universidade de Aveiro, Campus Universitdrio de Santiago * 3810-193 Aveiro, Portugal

Process control and automatic control systems play an
important role in the design and operation of modem
industrial plants, resulting in economical and safe
plant operation. Among other topics in the field, controller
tuning is particularly important because controller settings
severely affect the performance of the closed-loop system. In
addition, accurate settings from experimental dynamic data
are extremely useful when processes are too complex to be
modeled from fundamental principles. [1 Chemical engineer-
ing instruction should emphasize these facts. The unit we
propose to study has a nonadiabiatic plate-heat exchanger,
complex internal geometry, and nonlinear dynamics coupled
and reciprocally interacting with a heater tank without agita-
tion. In this unit, a monitoring-control system ui ng I ab i" :]
has been implemented. Multivariable control examples were
proposed, but the emphasis in this work was toward showing
the new, improved computer interface and the pedagogical
potential of the experimental unit. The PCT23 unit has also
been used as the main tool for developing advanced control
tracking in the controller.[3] In that work, a solution strategy
was developed based on a set of partial differential equations,
reflecting the complexity of the system model. In our case, an
experimental reaction curve combined with tested sintoniza-

tion techniques is considered as a viable method for tuning up
a PID controller. Similar laboratory pilot-scale experiments
have appeared elsewhere in the literature.[4 5] These include
computer-controlled units with a standard shell and pipe heat
exchanger and a steady external heat source.[4] The controlled
temperature is the exit hot stream, and the manipulated vari-

Carlos M. Silva is a professor of chemical engineering in the Department
of Chemistry at the University of Aveiro, Portugal. He received his B.S.
and Ph.D. degrees from the School of Engineering, University of Porto,
Portugal. His research interests are transport phenomena and membrane
and supercritical fluid separation processes.
Patricia F. Lito is a Ph.D. student in the Department of Chemistry at the
University of Aveiro, Portugal. She received her B.S. degree in chemical
engineering from the University of Aveiro. Her main research interest
focuses on mass transfer and membrane separation processes.
Patricia S. Neves is a Ph.D. student in the Department of Chemistry at the
University of Aveiro, Portugal. She received her B.S. degree in chemical
engineering from University of Aveiro. Her main research interest focuses
on biomass valorization and catalytic processes.
Francisco A. Da Silva is a professor of chemical engineering in the Depart-
ment of Chemistry at the University of Aveiro, Portugal. He received his
B.S. and M.Sc. degrees from Simdn Bolivar University, Venezuela, and his
Ph.D. degree from the School of Engineering, University of Porto, Portugal.
His research interests are in modeling and control, parallel computing,
and cyclic separation processes.

� Copyright ChE Division of ASEE 2008

Chemical Engineering Education

able is the cold stream flow rate with additional distu
introduced in the hot stream flow. The system identil
is carried out in the frequency domain by building an,
mental Bode plot diagram. This method has two draw
First, it's complex in that poor students lack understand.
to the frequency domain analysis requirements. Further
frequency response analysis is not practical for system
time constants -in the order of hours as in this labi
unit-because it needs five to six experimental runs
sinusoidal signal to obtain a complete Bode diagram.
experiment, the manipulated variable is the power to a
tank source and the disturbances are introduced in tl
flow stream. The open-loop identification is performed
the classic reaction curve with only a single experiment
with a power step perturbation inside the heater tar
resulting reaction curve is fitted directly in the time
using readily available worksheet program tools.[6] Ot
perimentsE51 focus on a theoretical homework profile, "v
more appropriate for advanced courses without experi
requirements. Undergraduate students in the Departr
Chemistry at the University of Aveiro receive lectt
fundamentals and applications
of process dynamics, simulation,
modeling, and control as part of j
four courses as follows: Instru- PID
mentation and Process Control,
Laboratory EQ4, Chemical Pro- T
cess Modeling and Simulation,
and Advanced Process Control. C a
Computer and PIID si
This paper focuses on the control- controller
ler tuning experiment of Labora-
tory EQ4.
This is a weekly, six-hour labo-
ratory where students are divided
into groups of three. Each experi-
ment lasts two weeks. In the first
week, students carry out the lab
exercise. In the second week, they
do the numerical calculations and
simulations that require compu-
tational support available in the
PC computer laboratory near the
wet laboratory. Assessment is
based on an individual oral quiz
and a report prepared by each ,
group. At the end of semester, a Km
selected group has the opportu- (K)
nity to present a longer report and
an oral presentation. In this final
report, the students can collect
the experimental results from the
other parties and prepare a review
of the accumulated results.

In our opinion, there are two ways to train students to tune
a PID controller: i) through the use of computer simulators
with powerful numerical libraries embedded in commercial
software such as Matlab/Simulink, Mathcad, and Hysys or
other specifically tailored applications; I9] or ii) by direct
experimentation9] -as in this experiment. With this experi-
ment, chemical engineering students have the opportunity to
study a small process unit to determine the PID controller
settings using the Process Reaction Curve Method combined
with Internal Model Control or Ziegler-Nichols tuning rela-
tions. These theoretical parameters are tested via closed-loop
experiments and the results are compared.

Experiments are carried out on PCT23 Process Plant Trainer
equipment shipped by Armfield.m101 It is a very flexible ap-
paratus that integrates a small pasteurization unit, and offers a
wide range of operating possibilities such as manual operation,
data logging with PC, direct digital control, and industrial PID
and PLC. 21 This equipment, schematically shown in Figure 1,
consists of a cold water feed tank, heater tank, plate-heat

Figure 1. Schematic of the experimental equipment.

Figure 2. Block diagram of the feedback control system.

Vol. 42, No. 2, Spring 2008

exchanger, holding tube with insulation, recycling pump, and
feed pump. A PC-based system logs all signals and uses the
Genesis software package where the PID control algorithm
is implemented.E101
The objective of this set-up is to heat the feed water from
temperature Tf to an exit temperature, T = T , using the plate-
heat exchanger and a hot stream from the heater tank at Thl.
Therefore, the control strategy consists of measuring T and
adjusting the power to the electric heater, Q , so that, regard-
less of disturbances, the exit temperature returns to T . The
holding tube is insulated so a pure time delay results; it and
irhh denote the water mass flows of the feed and the heating
circuits, and V is the liquid volume inside the heater tank.

Using the described control strategy, the controlled variable
is T, whose set-point is T =T , and the manipulated variable
is QR. In this experiment, a disturbance is introduced by
changing the cold water feed flow rate, ria, using a peristaltic
pump. Figure 2 (previous page) is the resulting block diagram
of the feedback control system, where: G., GR, G , Gm, and GL
are the transfer functions for controller, electrical resistance
heater, process, thermocouple-transmitter combination, and
load, respectively; Km is the gain that converts the set-point,
T' , to a voltage signal, T',, that is used internally by the
controller; E is the error signal; P'is the controller output;
and T'm is the measured temperature. Apostrophes identify
deviation variables calculated from the original steady state
values, for instance: T'm Tm- Tm,QR R - Q, etc.
In this experiment two different controller tuning techniques

- t -
Figure 3. Step response of a first-order system with
time delay, and the graphical analysisf, "1
required to obtain the parameters for the
Ziegler-Nichols tuning rules.

are tested: i) Process Reaction Curve Method combined with
an Internal Model Control Method (IMC) tuning rule; and
ii) Process Reaction Curve Method combined with Ziegler-
Nichols (ZN) tuning relations.1, "1
The Process Reaction Curve Method is an established
procedure for determining the parameters of an open-loop
transfer function with a single experimental test carried out
with the controller in manual. A step change in the controller
output (AP) is introduced and the measured process response,
reaction curve T(t), is recorded. In this experiment, a first-
order plus time delay model is selected and can be written in
the Laplace or frequency domain as:


Ke -

Eq. (1) includes the transfer functions for the electrical
resistance heater, the process, the thermocouple, and the
temperature transmitter, for a step input of magnitude AP:
P'(s)= AP / s - T'(s)= --- (2)
s(Ts + 1)
Taking the inverse Laplace transform, the time domain
response is:
AT(t)= KAP(1- e ( 0)') (3)
Note the system gain K, the time delay 6, and the time
constant T are the model parameters. Process gain is the ratio
of the change in the steady state value of AT to the size of the
step change AP [from Eq. (3): AT" = AT (t =c) = KAP], and
T may be found using several graphical methods.[' "11 Alterna-
tively, the three parameters may be estimated by nonlinear
There are many methods to select the PID controller set-
tings. The ideal PID controller equation illustrates the three
required parameters (gain K., integral time TI, and derivative
time TD):

P=P�+K, E(t)+ E(t)dt+ (t) (4)
T' dt
For a first-order plus dead time model, the IMC provides
the following tuning relations:11"1

1 2

0 TO
2 2T+ 0

where T is a design controller parameter normally chosen
as 6 < T < T.
Alternatively, controller settings may be determined using
the ZN tuning rules,
K= T, = 2, TD = 0.50, (6)

where 6 and S* = S/AP = K/T are determined by graphical
analysis of the process reaction curve shown in Figure 3.
Chemical Engineering Education

Accordingly: i) process gain K is the ratio of the change in
the steady state value of T divided by the step change AP; ii)
the root of tangent line drawn at inflection point S is the time
delay 6; iii) S is the slope of tangent line; and iv) extending
the tangent at inflection point to the steady state line T =
KAP, the intersection point corresponds to t = 6 +T. 3

The performance of the resultant feedback control 3
system has to be tested and evaluated prior to start-up of
an industrial plant, by studying the dynamic and steady 3
state characteristics of its response to some perturba-
tions. This task is accomplished using two laboratory 3
experiments, one for each set of suggested controller
settings [Eq. (5) or Eq. (6)]. 3


Table 1 shows the operating conditions, useful notes, 3
and necessary data as part of the laboratory controller
tuning experiment in steady state conditions. Super- 3
scripts 'o' and 'co' stand for original and final steady
state conditions, respectively [e.g., Po = P(t = 0) and P = 2
P(t = o)]. The computer interface of the PCT23 Process
Plant Trainer shows the controller output as a percentage.
Experimental procedure is as follows: Tat

a) Initialize experimental set-up and let system reach a
steady state.

b) Carry out an open-loop experiment (controller in manual) to
measure the process reaction curve by introducing a step change


12 313
S 312
10 311
08 309
06 307

04 - '\N t

0 -uU - -00 -0 - -0-

9 8 . . . . . . .
0 1000 2000 3000 4000 5000 6000
ure 4. Process reaction curve for operating conditions shown in
le 2, and first-order plus time delay model fitted to experimen-
data. The expanded area of the first 500s is given in the inset.

Vol. 42, No. 2, Spring 2008

Outline of the Experiment
Step Task Experimental Conditions Register Notes
a Reach steady-state P= 30% T * T�= T (t = ), etc.
mh = 4x103 kg /s * Computer interface shows P in
rmh = 6.2x10 3kg s percentage
b Open-loop experiment To = T� (step a) T(t) * Put controller in manual mode
to measure process reac- Input step in P: * Initial steady-state is the final condi-
tion curve AP = 15% = P= 15% tion of step a

c Wait for steady-state P= 30% T� * There is enough time to optimize
(e.g., same as step a) rh = 4x10 3kg/ s model parameters [Eq.(3)], carry
out graphical analysis (Fig.3), and
S6.2x10 3kg calculate controller settings using
Eqs. (5) and (6)
d Closed-loop experi- T = T� (step c) T(t) * Initial steady state is final condition
ment (controller settings P = 30% of step c
obtained by Internal K", T, T * Set-point is T� from step c
Model Control in step c) Input step in rh: * P varies with time
Amf (4 -2)x10 3kg s

e Reach same steady-state P= 30% T�
of step c ri 4x10 3kg / s
ih = 6.2x10 3kg s

f Closed-loop experi- T = T� (step e) T(t) * Initial steady state is final condition
ment (controller settings P = 30% of step e
obtained from Ziegler K,, T, TD * Set-point is T� from step e (or step c)
- Nichols equations in Input step in rh: * P varies with time
step c) Amf, (4 - 2)x103 kg / s

in the controller output (AP). Plot temperature T vs. time.
c) Operate system to attain a steady state. During this time

period, optimiz
delay model [E


315 A


S 8 0

313 -o oF " X x
x xo g D ^ �o o �o =ooo xjr
o a

312 0 o


t, S
0 500 1000 1500 20 00 3500 4000

Figure 5. Closed-loop responses obtained for the PID controller set-
tings determined by Internal Model Control tuning relations [Eq. (5)],
(xxx); Ziegler-Nichols relations [Eq. (6)], (ooo). Experimental condi-
tions and parameters are shown in Table 2.

in th
in th

Experimental Conditions, Observations, and Calculated Results
Open-loop identification experiment (Table 3, step b)
Experimental conditions:
m, 4 x 10 kg / s, mh 6.2 x103kg / s, T 39�C
Input step in P:
AP :30% -15%
Experimental observations:
T= T(t) shown in Figure 4.
Calculated results from process reaction curve
Model parameters [Eq.(3)]:
K = 0.8476 K/%, 0 = 120 s, T = 717.3 s (from nonlinear fitting AAD =0.073%)
PID controller settings from Internal Model Control Method [Eq.(5)]:
K, = 5.10 %/K, T = 777.3 s, TD = 55.4 s
Experimental parameters (from Figure 4):
- .' I 114 K / s; 0 = 120s, = 730s
PID controller settings from Ziegler-Nichols relations [Eq.(6)]:
K = 7.14 %/K, T = 240.0 s, TD = 60.0 s
Closed-loop experiments (Table 3, steps d and f)
Experimental conditions:
rh = 6.2 x 10kg / s, P 30%, Tp T 39�C
Input step in rm :
Amf, : (4 2)x10 3kg / s
Experimental observations for each set of PID parameters
T = T(t) shown in Figure 5.

After the experimental work proposed, the stu-
dents collected one reaction curve and two closed-
loop experiments with IMC and ZN tuning settings.
Table 2 summarizes the experimental conditions,
observations, and calculated results. The obtained
process reaction curve is presented in Figure 4
(previous page), as well as the results from a first-
order plus dead time model [Eq. (3)]. The results
of using the ZN rules are also shown in Figure 4.
The small deviation (AAD = 0.073%) does show
the excellent fit of the data. Furthermore, students
can also conclude that the process is self-regulat-
ing since its reaction curve is bounded and reaches
a new steady state after a step change at t = 0. It
should be noted that the student must realize the
reaction curve can be inverted, resulting in the
standard diagram (Figure 3).
Figure 5 shows the typical underdampened-load
responses of the closed-loop PID controlled system.

Chemical Engineering Education

:e the parameters of the first-order plus time
q. (3)] using a spreadsheet program and least-
squares method. Plot the resultant correla-
tion on the same plot as the experimental
data. Next, calculate the PID controller
settings using Eq. (5) (IMC). Using the
required graphical analysis of Figure 3,
compute the controller settings using the
ZN tuning rules [Eq. (6)].
d) Perform a closed-loop experiment
with the PID controller settings obtained
in step c) using IMC, introducing a step
perturbation in the feed mass flow. Plot
the temperature T vs. time.
e) Return the system to attain the same
initial steady state (i.e., final condition
of step c).
f) Perform a closed-loop experiment
with the PID controller settings obtained
from the c) ZN approach. Again introduce
the same step perturbation in the feed
mass flow and plot the temperature T vs.
time on the same graph of step d).
NOTE: In order to reduce experimental
time duration, the reaction curve can be
given to students before the laboratory
session. For a reduced two-week labora-
tory session, students can perform the
reaction curve and PID tuning calculation
e first week, and the closed-loop experiments
e second week.

For the same experimental conditions (Table 2), these
results emphasize the effect that different controller
settings have on system response. The ZN tuning rules
result in a faster response (more aggressive). This re-
sponse is due to a combination of higher Ko and lower
TI values:"11 7.14 %/K and 200.0 s (ZN), respectively,
compared to 5.10 %/K and 777.3 s (IMC). Students need
to be aware of this fact. The feedback control system
with IMC parameters exhibits a remarkably sluggish
response, that of the set-point intersected at 7600 s,
compared to ZN at 535 s.
Students should conclude there is no perfect control-
ler tuning method. The goal is to have good preliminary
education that can provide a starting point for additional
field tuning, especially when available process information
is incomplete or inaccurate.1111]

The proposed experiment is mainly oriented toward
system dynamics and controller tuning. Other useful tasks
may be considered by instructors, such as carrying out a
thermal analysis of the system to allow the estimation of
heat losses and global heat transfer coefficients. The same
experiment may be implemented using the industrial PID
and console available in the PCT23 unit. This set-up al-
lows us to change control strategy to a cascade control
At the end of this work students answer a survey, al-
lowing instructors to figure out the benefits and difficul-
ties found during its execution. Following a procedure
suggested by other authors,[12 the set of questions listed
in Table 3 was assessed from 1 (strongly disagree) to 5
(strongly agree). The results suggest that this experimental
work accomplishes the main objectives in general and does
contribute to students' understanding and interest in the field
of process control.

PCT23 Process Plant Trainer equipment provided by
Armfield10�1 is used to teach PID controller tuning. The
experiments introduce and solidify theoretical concepts by
obtaining approximate transfer functions or time domain
models from a process output response to some step input,
and by calculating the PID controller settings from typical
industry-developed tuning rules. They also provide the
means for experimental validation of controller performance.
Students do recognize that there are no unique methods to
estimate satisfactory controller settings and that additional
field tuning may be required.

The authors gratefully acknowledge the financial support

A Proposed Survey for Assessing the Usefulness
of This Experimental Work
The answers for all questions were classified as:
strongly disagree (1 point); disagree (2 points);
somewhat agree (3 points); agree (4 points); strongly agree (5 points).
Results refer to 32 students in 2005-2006.
Question Mean Standa
1. Were the concepts previously ac- 3.29 0.61
quired on process control sufficient to
allow you to carry out this work?
2. Is this experimental work connected 3.29 0.61
with the theory taught in other control
3. Is the available bibliography suf- 4.00 0.68
4. Were you able to do the experimen- 2.29 0.91
tal work without difficulty?
5. Were you able to do the calculations 2.00 0.78
without difficulty?
6. Were you able to interpret and dis- 2.50 0.65
cuss the results without difficulty?
7. Do you think you improved your 3.43 0.51
skills in controller tuning?
8. Did the practical work motivate 3.36 0.50
or increase your enthusiasm about
process control?
9. Did you find the experimental work 3.71 0.83
important for the understanding of
chemical process control?
10. Do you feel stimulated to take 3.43 0.65
future new challenges in the field of

from Programa Operacional "Ciencia, Tecnologia, Inovaqao"
QCA III and FEDER, project POCTI/EQU/46055/2002.

AAD Absolute Average Deviation
IMC Internal Model Control
E = T - T, Error signal
G, GR, G , Gm, GL Transfer functions for controller,
electrical resistance heater, process, thermocouple-
transmitter, and load
K Process gain
K Controller gain
Km =T'- /T'p , gain to express set-point (K) as voltage
signal (V)
m Mass flow, kg/s
P Controller output
PID Proportional-Integral-Derivative

Vol. 42, No. 2, Spring 2008

(Q Power of electrical heater, W
t Time, s

T Temperature, K

V Liquid volume inside heater tank, m3

ZN Ziegler-Nichols

Greek letters
A Deviation relative to initial steady state value;
Step change

T System time constant, s

T1, TD Integral and derivative time, s
6 Time delay, s

o,so Initial and final steady state conditions.

Variable expressed as voltage

Deviation variable
F Feed

H Heating circuit
M Measured value

Sp Set-point

1. Luyben, W.L., Process Modeling, Simulation and Controlfor Chemical
Engineers, 2nd Ed., McGraw-Hill, Singapore (1990)
2. Escribano, I.E, and EX. Ferragud, "Monitorizaci6n y control de una
plant piloto PCT23 con LabVIEW," in Seminario annual de Au-
tomdtica, Electr6nica Industrial e Instrumentaci6n. SAAEI'02, Alcala
de Henares (Spain), Septiembre: 373-376 (2002)
3. Xu, J-X, T-H Lee, and Y. Tan, "Enhancing Trajectory Tracking For a
Class of Process Control Problems Using Iterative Learning," Eng.
Appl. OfArtificial 1..,. // ..... 15, 53-63 (2002)
4. Famularo, J., "A Computer-Controlled Heat Exchange Experiment,"
Chem. Eng. Edu., 21(2) 84 (1987)
5. Reeves, D.E., and EJ. Schork, "Simulation Exercises for an Under-
graduate Digital Process Control Course," Chem. Eng. Educ., 22(3)
6. Partin, L.R., "Opportunities in PC and Mac Numerical Software for
Process Engineering, "AIChE Symp. Series, 91(304) 340 (1995)
7. Hergert, D., "A Closed Loop PID Control Program For Process Con-
trol, " Int. J. Appl. Eng. Ed., 5(1) 83 (1989)
8. Azevedo, S.E, E Oliveira, and C. Cardoso, "TEACON-a Simulator
for Computer-Aided Teaching of Process Control," Comp. Applic. in
Eng. Educ., 1(4) 307 (1997)
9. Young, B.R., J.H. van der Lee, and W.Y. Svrcek, "A Nonlinear, Multi-
Input, Multi-Output Process Control Laboratory Experiment," Chem.
Eng. Educ., 40(1) 36 (2006)
10. Armfield, "Instruction Manual: Process Plant Trainer," PCT23, Issue
7, England (1999)
11. Seborg, D.E., T.E Edgar, and D.A. Mellichamp, Process Dynamics
and Control, 2nd Ed., John Wiley & Sons (2004)
12. Abbas, A., and N. Al-Bastaki, "Onthe Use ofSoftwareTools for ChE Educa-
tion-Students'Evaluations,"( I.... .. i.,,. 36(3)236(2002)

Chemical Engineering Education



By Introducing an Environmental Management System

in the Student Laboratory

Universitat Politicnica de Valencia * Cami de Vera s/n. 46022 Valencia, Spain

The most efficient way to achieve an environmental
and sustainable development culture and prevent pol-
lution from industrial processes is to educate students
by our own example. For this reason, the university must be a
reference for future professionals who are to lead the industrial
processes. These leaders will be chemical engineering students
who, in the near future, will perform engineering tasks. There-
fore knowledge, principles, and basics related to sustainable
development should be introduced within the curriculum.[1, 2]
These principles could be easily introduced in subjects related
to Environmental Science and Technology, which constitutes
a very important aspect of chemical engineering education.
Engineering educators are responsible for achieving this goal,
but in order to do so, the scientific and technological funda-
mentals of Environmental Science should be explained on the
basis of sustainable development. These explanations can be
applied using a tool that is now more common in industry and
a subject in the chemical engineering studies curricula:[3] the
environmental management system.
An environmental management system is defined by the
International Organization for Standardization (ISO) as
"the part of the overall management system that includes
organizational structure, planning activities, responsibilities,
practices, procedures, processes, and resources for develop-
ing, implementing, achieving, reviewing, and maintaining
the environmental policy." Environmental policy is defined
as the "statement by the organization of its intentions and
principles in relation to its overall environmental performance,
which provides a framework for action and for the setting of
environmental objectives and targets."
There are a number of standards upon which one can model
different environmental management systems. The ISO 14001
environmental management system standard is the most
widely recognized framework, and many entities have their
environmental management systems certified as conforming
to ISO 14001.[4] The main features of these systems are:
S A voluntary approach oriented to developing positive
long-term objectives and progressing toward achiev-
ing them, rather than applying stiffpenalties for fail-
ing to comply with many itemized requirements.

Vol. 42, No. 2, Spring 2008

* A continual step-by-step improvement in the environ-
mental performance of enterprises and industries.
* A complete, . ,,1a. *. of the principle of sustainable
* An easy and natural. ,,1 , , .i. with other standards
such as ISO 9000, the Quality Management System.

The first objective of these systems is the same as that of
chemical engineering educators: To enhance a positive attitude
about environmental protection and management. Achieving
this objective will result, on a long-term scale, in more sustain-
able development within society.5, 6] The second objective is
to design elements and implementation steps. Both of these
objectives involve orientation and working familiarity with
environmental management system guidelines. This is not
always easy to achieve for workers and/or students because
they do not usually feel involved.
Further, the selected objectives should be achieved within
the more abstract concept of sustainable development. This
concept demands that the three main aspects of development
-economic, social, and environmental-be considered as

Maria T. Montaies is an associate profes-
sor of chemical engineering at the Technical
University of Valencia (Spain) where she
teaches environmental technology, and ana-
lytical and inorganic chemistry. She received
her B.S. and Ph.D. degrees in industrial
engineering from the Technical University
of Valencia. Her current research activities
include techniques related to pollution and
corrosion prevention.

Antonio E. Palomares is an associate pro-
fessor of chemical engineering at the Techni-
cal University of Valencia (Spain), where he
teaches environmental science and tech-
nology as well as analytical and inorganic
chemistry. He received his B.S. and Ph.D.
degrees in chemistry from the University
of Valencia. His current research activities
include techniques related to prevention of
pollution and environmental catalysis.

� Copyright ChE Division of ASEE 2008

a whole.7'9] Attempting to do so often produces conflicting
interests, and the solution-a successful integration-implies
an essential change from commonly held views on progress
and growth in human society. This integration is not explicitly
included in ISO 14001 systems. For this reason, educators
must provide the knowledge, concepts, and approaches of
sustainable development to students - who will soon contrib-
ute to society's material progress and growth.

Using the environmental management system as a tool, we
introduced the concept of sustainable development in chemi-
cal engineering education within the unit operations laboratory,
which is the facility most similar to an industrial facility. In this
way students become conscious in every session of the fact that
they are participating in an environmental management system
and trying to achieve further objectives related to environment
that will contribute to the sustainable development of society.
Students must be aware of generated hazardous waste and how
adequate management of it is fundamental to avoiding problems
in basic utilities such as drinking water, wastewater, or solid
waste treatment. Students must learn to try to minimize waste
production and the use of reagents while considering the social,
economic, and environmental importance of this minimization.
Students must work according to environmental and security
regulations not only because it is their obligation legally but
because they are conscious of its importance for society. To do
so, students must be supplied with the necessary procedures
and instructions. In this paper we show how the system has
been developed and implemented in the laboratory, what role
students have played, the main problems identified, and how
those problems have been solved.

Academic context
This work was undertaken in the Chemical and Nuclear
Engineering Department of the Technical University of
Valencia. This department teaches many subjects within
engineering studies such as industrial engineering, chemi-
cal engineering, and materials engineering. Many of these
subjects are related to environmental science, including
environmental science and technology, environmental
technology, water pollution, air pollution, solid wastes,
environmental analytical techniques, environmental
management, environmental impacts, radioactive pollu-
tion, and drinking water treatments. These subjects are
scheduled for the later years of a student's studies as they
build upon earlier knowledge to introduce concepts and
techniques related to water pollution, air pollution, and
hazardous wastes, the management of these concepts, and
the main preventive tools used in industry.
The plethora of subjects related to the environment
taught by our department was the basis for our objective
of introducing sustainable-development principles and
objectives throughout the students' academic tasks.

Among the various engineering studies, the Chemical and
Nuclear Engineering Department mainly works with the
Industrial Engineering School. This higher education center
has been certified under the ISO 14001 Environmental Man-
agement System.[101
The principal objective of this system is to improve the
center's activities from an environmental point of view, to
properly treat its wastes (paper, plastics, hazardous wastes,
etc.), to reduce its consumption of raw materials, to create a
positive attitude toward the environment, and to integrate the
principles of sustainable development.
As in all environmental management systems, the people
affected should be integrally involved, including not only
the staff of the center but also the students. Although the
students are the largest part of the Industrial Engineering
School, it has been demonstrated that they do not know what
the environmental management system is, what it implies, or
what their role is within it. Usually their only contribution
to the environmental management system consists of putting
waste in the appropriate container as a rote action, without
being conscious that they are part of a global management
system trying to achieve broader objectives. For this reason,
and because we are responsible for environmental subjects in
engineering studies, it is our duty to involve students in the
environmental management system and to use it to introduce
the principles of sustainable development.

In Spain, the docent responsibilities and student laborato-
ries depend on the various departments within the university.
Based on the implementation of an environmental manage-
ment system in the Industrial Engineering School, the Chemi-






Figure 1. Steps to implement an environmental
management system.[1

Chemical Engineering Education

cal and Nuclear Engineering Department is implementing an 1. Environmental Policy
environmental management system in accordance with the The first step was approving the department's environmental
ISO 14001 specifications. The steps toward implementation policy. This environmental policy is presented in Figure 2.
are contained in Figure 1. Referring these steps to the student's Many points of the environmental policy are directly related
laboratory, we have: to students, and according to it our duty as engineering educa-

Ingenera Quimlca y Nuclear
The Chemical and Nuclear Engineering Department is aware of the need to incorporate the environmental ethics to all
its activities and, in accordance with the Environmental Policy of the Polytechnic University of Valencia, it has decided
to assume that responsibility. The University, and by extension its Departments, have, as a main target, the creation, de-
velopment and transmission of Science, Technology and Culture. They are an instrument for the advance of our society
and for intellectual development, as well as for the promotion of the freedom of thought. Through all this, it is possible
to influence society by introducing improvements in the relation of the human activity with nature and in the manage-
ment of the natural resources.
The Department assumes the contents of the Agenda 21 document from the United Nations. It assumes the responsibil-
ity to generate science, technology and culture, according to solidarity principles with all the contemporary world and
under sustainability criteria in order to extend it towards the future generations.
As part of a Higher Education Institution, the Department tries to raise awareness in all its members, as well as in the
students, for the preservation and improvement of the Environment. It is conscious that through instruction and research
it plays an exceptional role in the transformation of society.
As an instrument to reach these aims, the Chemical and Nuclear Engineering Department is committed to implement an
Environmental Management System: UNE-EN-ISO 14001 and consequently to try to maintain the continuous improve-
ment of its environmental practices. In particular:
1. Analyzing and evaluating the activities developed in the Department, according to the Environmental Management
System, and trying to determine and to diminish the environmental impacts that can be derived from them.
2. Providing an environmental instruction adapted to all the students and workers.
3. Providing to the members of the Department appropriate training and environmental information related to their
4. Fulfilling all the environmental legal requirements, trying to go beyond the prescribed minimums.
5. Rationalizing the consumption of raw materials, resources and energy.
6. Preventing the possible pollution and avoiding, as far as possible, the spills, the emissions and the wastes generated
in the different activities.
7. Managing the wastes generated according to laws.
8. Informing of its objectives to the university community, favoring its participation in the environmental instruction
of the students.
9. Working with the companies, institutions, and people that develop their activity with the department, to help them
and to commend them for improving environmental performances.
To carry out these commitments, challenging environmental objectives will be established. They will be public and, as
far as possible, quantifiable, evaluating continuously the goals.
Annual reviews will be made that will contain a revision of the environmental performances of the department and
these will become public, spreading the expected objectives to all the university community
The Chemical and Nuclear Engineering Department Director

Figure 2. Environmental Policy of the Chemical and Nuclear Engineering Department
of the Technical University of Valencia.
Vol. 42, No. 2, Spring 2008 107

tors is to provide and foment environmental instruction on the
basis of the sustainable development principles adapted to all
students (points two and eight). In the laboratory, students are
the main consumers of raw materials, resources, and energy.
Therefore, according to point five, they must rationalize
the consumption of these resources. They have to prevent
possible pollution and avoid, as best as possible, the spills,
emissions, and wastes generated in different activities (point
six). Finally, according to point seven, they must manage the
wastes properly in accordance with environmental laws. As
faculty, we have to supervise and stimulate them to achieve
these objectives, as well as to not only be cognizant of the
Environmental Policy but also to develop new attitudes and
aptitudes more consistent with the principles of sustainable

2. Environmental Revision
The second step was to analyze the department's envi-
ronmental situation, including how it manages wastes, the
consumption of raw materials, energy, etc. This analysis
unveiled environmentally strong and weak points used to es-
tablish environmental goals to be achieved. In-lab discussion
was used to alert students to these goals and how they relate
to sustainable-development objectives, thereby encouraging
student participation in the continuous improvement process
required by ISO 14001.

3. Environmental Objectives
The third step was to establish objectives to be achieved.
These objectives were related to different activities, but one
of the most important objectives was to involve the students
in the environmental management system in order to develop
the principles of sustainable development.

4, Documents: Procedures and Instructions
The last step was the preparation of a manual with the
necessary procedures and instructions. The most important
in the student's laboratory are the following:

- IQN-P-001: Procedure for the identification of sig-
nificant impacts. This procedure aims to identify and
quantify the impact of laboratory management on the
environment, society, and the economy.

- IQN-P-002: Procedure for the identification and up-
dating of the legal requirements.
- IQN-P-003: Procedure for environmental instruction.
This procedure shows how to develop informative tasks
in the laboratory. This information given to the students
will not only be related to environmental issues, but
also to cooperation and sustainable development.

- IQN-P-004: Procedure for writing and controlling
environmental management system documents.

- IQN-P-005: Procedure for control of the wastes.
This procedure includes classification of the waste
indicating its hazard, the possible risks of inadequate
control of it, and recommendations to reduce expenses
derived from its management.
- IQN-P-006: Procedure for management of raw materi-
als and natural resources. This procedure includes
recommendations for reducing consumption of raw
materials and natural resources, and for reducing
expenses derived from their use.
- IQN-P-007: Procedure for environmental control
of dealers. This procedure encourages dealing with
companies that perform their activities according to
the principles of sustainable development.
- IQN-P-008: Procedure for emergency situations.
- IQN-P-009: Procedure for detecting and correcting
inadequate environmental management system perfor-
mance and implementing future preventive actions.
- IQN-P-010: Procedure for internal and external envi-
ronmental communication.
- IQN-P-011: Procedure for internal audits of the envi-
ronmental management system.
- IQN-P-012: Procedure for revision of the environmen-
tal management system.

- IQN-I-001: Instructions for proper hazardous wastes

- IQN-I-002: Instructions for management of waste

- IQN-I-003: Instructions for management of waste

- IQN-I-004: Instructions for management of used elec-
tronic equipment.

- IQN-I-005: Instructions for hazardous substances
identification in the shopping process.

- IQN-I-006: Instructions for work in the laboratory
according to environmental and sustainable principles.

- IQN-I-007: Instructions for the development of new,
practical, laboratory classes according to environmen-
tal and sustainable principles.

For the students, the most important instructions and proce-
dures presented in the first class are: IQN-P-001, IQN-P-003,
IQN-P-005, IQN-P-006, IQN-P-008, IQN-P-009, IQN-I-001,
IQN-I-002, IQN-I-003, and IQN-I-006. All allow students to
actively participate in the environmental management system
because they mainly relate to: the proper management and
minimization of wastes and reagents; the critical analysis of
the system in relation to sustainable-development principles;
and carrying out adequate sustainable development and en-
vironmental work.

Chemical Engineering Education


The most active student participation is developed in the
laboratory. For this reason we emphasize applying the envi-
ronmental management system to the teaching laboratory.
In this way students are more conscious in every session
that they are participating in an environmental management
system. They learn that the principles that guide this system
can be applied afterward in industry and that these principles
are the same as those from sustainable development. Among
other things, students must try to minimize waste production
and reagent consumption, and be sure to work according to
environmental regulations and the sustainable-development
principles. To achieve these goals, we supply students with
adequate explanations, concrete examples, and the necessary
procedures and instructions.

Two problems identified with applying the environmental
management system to the student laboratory were: 1) the
proper management of varied wastes generated in the chem-
istry laboratory due to the great diversity, and 2) the sequence
of courses. Subjects related to environmental science are
upper-level courses. Experimental subjects, however, are
pursued in the student's laboratory from the first year of the
student's studies. At this level, they only have a general sense
of what an environmental management system is and what
the principles of sustainable development are.
To solve these problems, the following actions were taken:
- Thefirst day in the laboratory, students receive a theo-
retical explanation of the department's environmental
management system. The explanation includes how
the objectives of this system are related to the prin-
ciples of sustainable development, and how students
themselves could apply these principles in society
after finishing their studies. The most important proce-
dures and instructions used in the laboratory are also
explained to the students.
- In each laboratory class, students have to write a re-
port of their results that includes an environmental and
sustainable evaluation of their work. This evaluation
addresses the identification of the reactants used and
the wastes generated. They must evaluate the cost of the
experiment as well as determine the composition of the
wastes and characterize .1-, ,,.i ... . , i,, to environmen-
tal laws. Then, they have to decide if the waste can be
recycled, disposed of down the drain or in the general
garbage, or if it must be collected in specific containers.
To make this work easier, students receive a handout
(shown in Table 1, next page) with an example from a
chemistry laboratory exercise. They also use this page
to gain awareness of the type and quantity of reagents
used and the waste produced. In this way, it is easier
for them to evaluate the work from an environmental
and economic point of view. Additionally, they reference
the bylaws pertaining to water pollutants and proper

hazardous-waste management.
- In each session, students must propose alternatives to
improve the practical laboratory class from the per-
spective of sustainable development. Concretely, they
have to propose alternatives, when it is possible, for
the used reactants by looking for other chemicals with
a lower environmental, economical, and social impact.
They also have to propose alternatives for proper waste
management, and they can even make ., .. * ..
about the entire process. Initially these i... . ... are
more focused on the minimization of wastes, but later
they consider the entire process from an environmental,
social, and economical point of view.
- The last day in the laboratory, students have to discuss
the different alternatives. This is probably the most
active participation from students in the environmental
management system because they usually find new
environmental solutions and make new environmental
,,,l, ... related not only to the generated wastes
but also to the development of the environmental policy,
the inclusion of new facts in the environmental revision,
and the criticism and development of the procedures
and instructions to be more adequate for the practical
laboratory classes. As an example of these proposals,
students have i ,,,. � ... .i, v1iv , Statement 7of the
environment policy by adding the necessity of going
beyond the legal .ii,,,i; ..ii These r,, ,. i.. are
made according to procedure IQN-P-012.

The last two points are the most difficult for students -par-
ticularly for students in the first year of their studies-as it
is much easier for last-year students who have already taken
numerous classes related to Environmental Science and Tech-
nology. In addition, students in last year of their studies are
more interested and active in the practical laboratory classes.
They become more conscious that they are a part of the envi-
ronmental management system and that the application of this
system can contribute to sustainable development.

Nevertheless, the results obtained are very encouraging. In
fact, we have approximately quantified the consumption of
reagents per student and the production of wastes per student
in some experiments carried out in the laboratory, and we
have compared them between the first and the last years of
study. Table 2 (next page) shows an example for the titration
of hydrochloric acid (a typical titration necessary for various
laboratory classes). The results show that, excluding acci-
dents, there is a clear decrease in the consumption of reagents
and the production of wastes in a student's last academic year.
This decrease can be attributed not only to students' greater
experience, but also to their greater awareness.

Therefore, the environmental management system is a
tool that can easily be applied to introduce the principles
of sustainable development in all the aspects of the future
process that will be controlled by the students when they
join the work force.

Vol. 42, No. 2, Spring 2008


It is possible to introduce the concept of sustainable
development in engineering education by implementing
an environmental management system in the students'

In the laboratory, students learn to reduce the consump-
tion of raw materials, resources, and energy; to prevent pol-
lution; to reduce the generation of wastes; and to manage
the wastes generated according to environmental laws.

Also in the laboratory, students learn to propose alternatives
for its management to improve the laboratory work from an
environmental, economical, and social point of view.

Finally, through all these aspects, students are more
conscious of the fact that they are participating in an en-
vironmental management system and that its objectives
and methods can easily be applied to their future jobs with
respect for the principles of sustainable development.

Chemical Engineering Education

Illustrative Form to Be Filled in By Students After Each Practical Laboratory Class
SUBJECT Chemistry laboratory
STUDIES Chemical Engineering YEAR 2nd
CLASS No. 5 Redox titration
OBJECTIVES: Determination of the iron concentration present in a problem solution by means of a redox titration, using
MnO4 and Cr2,O as oxidant agents.
Reagent Mass (g) or Volume (ml) Concentration Comments
Na2C2O4 0.22 g/100 ml 2.201 g/1
H2SO4 10 ml
KMnO, 70 ml 0.1 N
Problem solution (Fe 2, Fe+3) 20 ml
SnC12 In excess
HgC12 10 ml 0.25 M
Zimmerman solution 25 ml (Mn 2, H2SO4, H3PO4)
H3PO4 5 ml
Cr2,O 50 ml
LIQUIDS Mass (g) or Volume (ml) Concentration (ppm) Type
CO2+Mn+2+ H2SO4 140 ml [Mn+2]= 257.9 Hazardous waste
Fe+3+Sn 4+Cl +HgC1,+ 85 ml [Fe 2]=10259.3; [Cl]= 1044.12; Hazardous waste
Zimm.+Mn+2 [Mn+2]=475.2
Fe+3+Sn 4+Cl +HgCl1+H3PO4 80 ml [Fe+2]=10970; [Cl]= 1044.12; Hazardous waste
+HSO4+CrO,0 [Cr+3]=866.6
GASES Mass (g) or Volume (ml) Concentration (ppm) Type

SOLIDS Mass (g) or Volume (ml) Concentration (ppm) Type

Evolution of the Consumption of
Reagents Per Student and the Production of Wastes
Per Student in the Titration of Hydrochloric Acid
Mass (g) or Volume (ml)
2nd academic year 5th academic year
NaCO3 -0.85 g -0.45 g
HC1- 0.1N -100 ml -30 ml
Phenolphthalein -6 droplets -4 droplets
Distilled water -500 ml -300 ml
Mass (g) or Volume (ml)
2nd academic year 5th academic year
Na2CO3 -4.5 g/1 -150 ml -75 ml
HC1 -80 ml -20 ml
NaHCO3 + NaCl -70 ml -60 ml
+ phenolphthalein


1. Hailey, J., "Management Education for Sustainable Development,"
Sustainable Development, 6(1), 40 (1998)
2. Springett, D., and K. Kearins, "Gaining Legitimacy? Sustainable De-
velopment in Business School Curricula," Sustainable Development,
9(4), 213 (2001)
3. Minayev, A.A., V.V. Prisedsky, G.S. Klyagin, V.I. Ignatov, and T.J.
Oliver, "ISO 14000 Environmental Management Systems for Engineer-
ing Students," Global J. of Engineering Education, 3(2), 151 (1999)
4. Baraza, J., and R. Torres, "Analisis Detallado de la Norma ISO 14001,"
Ingenieria Quimica, 32(367), 163 (2000)
5. Strachan, P, I. Sinclair-McKay and D. Lal, "Managing ISO 14001
Implementation in the United Kingdom Continental Shelf (UKCS),"
Corporate Social Responsibility and Environmental Management, 10,

6. Rwelamila, PD., A.A. Talukhaba, andA.B. Ngowi, "Project Procure-
ment Systems in the Attainment of Sustainable Construction, "Sustain-
able Development, 8, 39 (2000)
7. Jischa, M.E, "Sustainable Development: Environmental, Economic,
and Social Aspects," Global J. of Eng. Educ., 2(2), 115 (1998)
8. Giddings, B., B. Hopwood, and G. O' Brien, "Environment, Economy
and Society: Fitting Them Together into Sustainable Development,"
Sustainable Development, 10(4), 187 (2002)
9. Hopwood, B., M. Mellor, and G. O'Brien, "Sustainable Development:
Mapping Different Approaches, " Sustainable Development, 13(1), 38
11. Paez-Sandubete, J.M., and E Carrasco-Fenech, "La Normativa Sobre
Sistemas de Gesti6n Medioambiental: Un Estudio de las Aproximaciones
de la Uni6n Europea y la International Organization for Standardization,"
Revista Mensual de Gestion Ambiental, 1(6), 10 (1999) 1

Vol. 42, No. 2, Spring 2008

i]=ll learning in industry

Challenges of Implementing



As Part of a Nontraditional Industrial Ph.D. Dissertation

Auburn University * Auburn, Alabama 36849
To many people the notion of a distance-education
doctorate in engineering may seem ridiculous enough
by itself, but add the fact that the prospective student
intends to maintain full-time employment as a senior process
engineer with a chemical manufacturing company, and the
ridiculous notion appears to become an impossibility. Indeed,
convincing a university and a corporation, two notoriously in-
flexible institutions, to do as much "outside the box" thinking
as was required for this endeavor was no small task. Despite
the potentially daunting obstacles, however, and through a
unique partnership between Evonik Degussa Corporation in
the United States, Evonik Degussa GmbH in Germany, Au-
burn University, and the University of South Alabama, this
seemingly impossible proposition has become a reality.
This article will describe the conception and organization
of this unique and very nontraditional research project from
the perspective of the student who is close to completing this

SAlso of: Evonik Degussa Corporation, 4301 Degussa Road, Theodore,
AL 36590

Jeffrey Seay is currently a senior process engi-
neer for Evonik Degussa Corporation. He has
more than 11 years of industry experience in
chemical process design and engineering. He
received his B.S. (1996) from Auburn Universi-
ty and M.S. (2004) from the University of South
Alabama. In addition to his industrial experi-
ence, he is currently pursuing a nontraditional
industrial Ph.D. from Auburn University, while
concurrently maintaining his industrial career
in Mobile, Ala., where he resides.

Mario Eden is presently an assistant professor
in the Department of Chemical Engineering
at Auburn University. He received his M.S.
(1999) and Ph.D. (2003) degrees from the
Technical University of Denmark, both in
chemical engineering. His work seeks to
advance the state of the art in process sys-
tems engineering research and education
through innovative and novel systematic
methodologies for integrated process and
product design.

� Copyright ChE Division of ASEE 2008
Chemical Engineering Education


This column provides examples of cases in which students have gained knowledge, insight,
and experience in the practice of chemical engineering while in an industrial setting. Summer
internships and co-op assignments typify such experiences; however, reports of more unusual
cases are also welcome. Description of the analytical tools used and the skills developed during
the project should be emphasized. These examples should stimulate innovative approaches to
bring real-world tools and experiences back to campus for integration into the curriculum. Please
submit manuscripts to Professor W.J. Koros, Chemical Engineering Department, Georgia Institute
of Technology, Atlanta, GA, 30332-0100.

unusual journey. At each step along the way, compromises
from all parties have been required, but in the end an environ-
ment was established whereby everyone stood to gain from
the process. As each step of the process is described, it will
be accompanied by some first-hand lessons learned from the

The real key to making this unlikely dissertation project a
reality was to negotiate a scenario where all parties involved
-the student, the universities, and the company-had some-
thing to gain from a successful collaboration. For the student
the benefit is clear, the chance for achieving the Doctor of
Philosophy degree while maintaining a career. For the uni-
versities, the benefits include exposure to industrially relevant
research and processes and the opportunity to apply theory to
real applications. Additionally, universities can benefit greatly
from the improved intellectual diversity stemming from add-
ing industrial experience to academic research groups. For
the company, the benefits come from the creative thinking
required of the Ph.D. student, which can lead to an increased
potential for innovation. Additional company benefits come
both from the infusion of fresh mindsets into the research and
development process and from establishing a relationship with
the university to identify talented students for future employ-
ment, as well as the opportunity for corporate branding. By
establishing a win-win-win scenario, everyone is motivated
to find a way to ensure a successful outcome.

The research project was originally conceived as a con-
ceptual process-development project for the production of an
industrial chemical from renewable, bio-based feed stocks."1
The original objectives included the development of a con-
ceptual process and an assessment of its economic viability.
In addition, laboratory experiments were to be carried out
to gather the data needed for the process-design activities.
This industrial project in and of itself, however, would not
necessarily have contained sufficient academic rigor for a
Ph.D. dissertation. To address this potential shortcoming, the
original project has been incorporated into the other systems-
engineering research work at Auburn University. In this way,
the project could be given a broader scope, yet the original
goals were preserved by including the industrial application
as a case tudl\ '[1
In nontraditional projects like this one, it is incumbent
upon the research advisor to ensure the resulting dissertation
has sufficient depth. This was accomplished by ensuring
that there was enough flexibility in the scope to allow the
student to follow leads and dive more deeply into avenues of
interest that arose as the project progressed. Because of this,
the project evolved significantly as it moved along. In fact,
the final results were quite different from what was initially

envisioned. This means that care must be taken in choosing
a research topic. The project must have a clear focus, but be
open enough to allow the creativity that is vital to intellectual
development of the student. Particularly projects that include
the development of generally applicable methodologies or
mathematical techniques are good candidates. In this way
the development of the methodology or technique can be
openly published, whereas the results of the application of the
methodology or technique to the specific industrial research
topic can remain proprietary. By framing the research in this
way, the practical outcome desired by the industrial partner
and the scientific contribution desired by the university can
both be accommodated.
With any collaborative research project, the different parties
involved do not necessarily share the same objectives. This
project is no different; therefore it is important to ensure that
the objectives of both the university and the industrial partner
are defined and addressed. The academic objectives are usu-
ally based on a "process of discovery" where scientific merit
is favored over specific results. From the perspective of the
university, the ultimate goal is the advancement of scientific
knowledge on a research subject. The objectives of the cor-
poration, however, usually have a different focus. In industry,
the objectives are usually based on predefined deliverables
with economic viability being considered at each step. From
the perspective of the corporation, the ultimate goal is a posi-
tive return on the research investment. Framing the research
project to incorporate the objectives of both the university and

Figure 1. Stakeholders in the proposed research project.

Vol. 42, No. 2, Spring 2008

the industrial partner is important for successful collaboration.
Developing a clear scope of work with the principle objectives
defined improves the likelihood of satisfying the expectations
of all the research parties.

When defining the scope of the research project, several
organizational challenges had to be addressed to ensure a
successful collaboration. First and foremost is establishing the
need for flexibility from the student, the university, and the
industrial partner. Research is a fluid process and it is nearly
impossible to force the process to fit into a rigid schedule.
From the student, flexibility with regard to work and study
schedules is needed; from the university, flexibility with
regard to residency requirements and in what order the indi-
vidual requirements of the Ph.D. degree are met is needed;
and from the industrial partner, flexibility with regard to work
hours and vacation schedules is tremendously beneficial.
Nearly as important as establishing the need for flexibility is
establishing channels of communication so no one is left out
of the loop. With research partners in two universities and on
two continents, good communication is critical. Determining
a schedule for update meetings and status reports early in the
process can help to ensure that everyone involved is informed
regarding the progress of the research. In order to ensure that
company goals are met, a representative from Evonik Degussa
was included on the research committee.
Another key item considered during the organization of this
project was determining where and how this research fits in
with current research being done at Auburn University. Since
this research was conceived outside the university, organiz-
ing funding for the project could have been a challenge. In
this case, the research is wholly funded by Evonik Degussa.
It may at first glance seem surprising that a company would
be willing to fund such an endeavor solely to benefit an
employee. Since this research was going to be conducted by
Evonik Degussa regardless, however, including it as part of a
Ph.D. dissertation adds tremendous value. Since the industry
researcher and the student are one and the same in this case,
the potential for creative discoveries is greatly improved.
With this arrangement, the student is motivated not only by
career goals, but by the chance to achieve the highest degree
in the field. For others considering a similar path who work
for companies without such a well-developed research his-
tory, however, grant money may also be a potential source
for funding.
Regardless of the source, it is important to accurately
forecast the total cost of the project. By spending the time to
estimate the total cost over the life of the project, the issue of
running out of money before all the academic requirements are
met can be avoided. Some lessons learned from the budgeting
process of this project are listed in Figure 2.
Finally, since this research must fit in with the normal job

Lessons Learned: Budget
* Accurately determine the expected dura-
tion of the research project. The disserta-
tion will include additional elements be-
yond the industrial portion of the research,
so it is important to include these when
estimating the project duration.
* Decide how university tuition and fees will
be paid. Since the research was not con-
ceived at the university, funds for tuition
waivers or stipends may not be available.
* Determine who will be responsible for
travel costs for both the student and aca-
demic advisor. Additional costs for attend-
ing technical conferences and seminars
may also need to be included.

Figure 2. Some lessons learned regarding
the budgeting process.

function of the student, it is important to organize how hours
during the work day will be allocated between the research
project and otherjob functions. This research project has been
organized as an Evonik Degussa engineering project with a
fixed budget to account for research hours spent during the
work week. The original budget was based on allowing ap-
proximately 30% of the week to work on the research project.
Depending on the phase of the project, however, more or less
time was spent as required.
Despite the time allowed during the work week, a significant
amount of the student's own time is required. In this regard,
the effort is similar to the effort required for a traditional
Ph.D. Although the time commitment is significant, a student
with several years in industry can draw on this experience
with regard to both problem solving and time management
in general.
One potential problem is drawing the line between what part
of the research is focused on meeting the goals of the company
and what part is solely focused on meeting academic require-
ments. Clearly, activities such as completing coursework
requirements are solely academic. Since the development of
a Ph.D. candidate requires time to be spent exploring various
avenues of research, it can be difficult to determine what work
is being done to meet the company goals and what work is
being done to meet the additional requirements for academic
rigor demanded by the university. Therefore it is important to
establish research goals and milestones up front so progress
can be easily measured.
In summary, it is important to realize that balancing work,
school, and sanity is not always easy. Any student consider-
ing this path must have advanced time-management skills.
In other words, personal organization is as important as the
Chemical Engineering Education

Lessons Learned: Conflict
* Definition of pre-existing intellectual
property: It is important to establish what
each side already knows with regard to the
proposed research.
* Ownership of any patents that arise from
the research: Patent ownership can be a
huge source of conflict; negotiating an own-
ership and royalty agreement up front may
help to avoid this potential conflict.
* Publication of research findings. Since the
research may contain business-sensitive
information it is important to determine
what can and cannot be published and
who will make this decision.
Figure 3. Some lessons learned regarding
identifying potential sources of conflict.
organization of the project. Without good organization, it
is easy to feel overwhelmed by the demands of school and
career. Understanding of these demands from supervisors
at work and from the academic advisor can help make this
burden manageable.

Even with the most well-organized projects, conflict be-
tween the partners will arise. To help minimize this potential
conflict, it is important to consider where conflict might arise
and take preemptive action to avoid it. One primary source of
potential conflict is over the ownership of intellectual property
generated as a result of the research. In the case of this project,
a thorough research contract has been entered into between
Evonik Degussa and the two universities. In the process of
negotiating these contracts, it became clear that there were
two competing interests regarding intellectual property: The
university does not want to "give away" its innovations, and
the company does not want to pay royalties to use its own
technology. Clearly, addressing intellectual property (IP) is-
sues before they become conflicts is wise. In the case of this
research project, the scope was divided between academic
objectives and industrial objectives to help settle any intel-
lectual property conflicts that may arise. By dividing up the
anticipated intellectual property before it is generated, serious
conflict can be avoided. In addition, all department faculty
members were included in the IP agreement. This allowed
frank and open discussions regarding the research without
compromising confidential research results.
Another potential source of conflict is the duration of the
research project. Because the Ph.D. student must be allowed
time to develop creative solutions to problems and explore
alternate avenues of research, the pace of the project may
be slower than the pace to which industry is accustomed. To
Vol. 42, No. 2, Spring 2008

avoid a possible conflict, it is important to outline a schedule
up front, including milestones and a general timeline. In the
case of this research project, a three-year timeline was pro-
posed to meet the industrial and academic requirements. This
timeline was acceptable to Evonik Degussa, and reasonable
for a Ph.D. student already holding a master's degree. Some
lessons learned regarding identifying potential sources of
conflict are listed in Figure 3.
Conflict is a normal part of business, and this collaborative
research project is no exception. Even though conflict can
not be avoided entirely, brainstorming to look for possible
sources of conflict and addressing them from the onset can
help to streamline the process. Although there is no universal
right way to address potential conflicts, it is well worth the
time to look for and discuss them before any money or time
is invested on collaborative research.

A primary part of the academic experience is publication in
technicaljournals and presentation at conferences. As natural
as this process is in academia, it is often discouraged in indus-
try for reasons of protecting business-sensitive information.
These two conflicting interests can also cause problems for
the industrial Ph.D. student. For this research project, the
importance of publications and technical presentations was
discussed before any work began. The agreement reached
allowed publication and presentation of general research
findings, while specific data was withheld. This agreement
was an acceptable compromise for all sides. As a result of this
agreement, the total scholarly output from this research so far
includes four peer-reviewed publications and 10 technical
presentations at national and international conferences.

Since the requirements for the Doctor of Philosophy degree
include coursework as well as research, being located so far
from campus presents challenges for a prospective student.
Obviously, driving more than 200 miles just to attend class
is not practical. Fortunately in this case, all graduate courses
in engineering at Auburn University are available through
distance education. The distance education option is really
a necessity for a nontraditional student. Another avenue to
explore is transfer credit. Since many universities allow at
least some transfer credit, it may be possible to take some
courses at a nearby university to avoid having to take all
classes via distance education. Auburn University allows up
to 12 hours of transfer credit to count toward the 30 hours of
graded coursework required. In addition to the 30 hours of
traditional graded coursework, Auburn University requires
a further 30 hours of ungraded coursework as well. This
requirement was met by research and dissertation as well as
directed study credit.

Lessons Learned: Final Notes

* Negotiate as much as possible up front.
* Brainstorm early and often to anticipate
potential roadblocks.
* Secure management commitment up
* Be prepared for surprises along the way!

Figure 4. Some final lessons learned regarding the non-
traditional Ph.D. process.

Not only does the geographic distance create challenges
for completing coursework, it can also be an obstacle for the
normal interaction between a student and advisor that is so
critical to the student's development. To help bridge this gap,
it is critical that both the student and the advisor be comfort-
able using long-distance collaboration tools such as e-mail,
video conferencing, instant messaging, and Web-based meet-
ing tools. If used effectively, these tools can create an open
forum for communication and discussion.
Despite advances in technology, the use of long-distance
collaboration tools can never completely take the place of
face-to-face conversations. Because of this, regular visits to
Auburn by the student and to Evonik Degussa by the advisor
are important. Initially, three or four face-to-face meetings
were scheduled to discuss project planning, resolve intel-
lectual property issues, and determine the overall direction
of the research. Once the research work began, two or three
meetings per semester were planned to review the progress
with the other research committee members at Auburn Uni-
versity. Meetings were held both atAuburn and on the Evonik
Degussa plant site. As the research progressed, fewer face-to-
face meetings were required while more extensive use was
made of long-distance collaboration tools.

In order to truly develop as a Ph.D. candidate, participation
in a research group is also important. From the academic side,
this research is folded into the research group of the academic
advisor. This was a tremendous advantage of the partnership
with Auburn University. Since the research project fit well
with other research already being done at Auburn, there has
been ample opportunity to learn from, and contribute to,
other research in this area. Because of this it is important to
spend time interacting with the other students in the research

group, not just the advisor, during scheduled visits to campus.
Interacting with other students can enhance creativity due to
an exchange of ideas from others working on similar projects.
In addition to campus visits, participation in technical confer-
ences and seminars with other members of the research group
is a good way to achieve this interaction.

Integrating industrially relevant research topics into an
academic setting is an important goal for providing balance
to a chemical engineering department. Through collabora-
tion with an industrial partner on an academically interest-
ing and industrially important research topic, this goal can
be achieved. Although this project is unique for all parties
involved, the results of the collaboration have so far been
successful. This experience can serve as a model for other
manufacturing companies looking to bring an academic per-
spective to a research project, and for universities looking to
bring an industry focus to chemical engineering education.
Although many of the points raised in this contribution may
appear obvious when they are put in print, making such a
project work in practice is no trivial matter.
In conclusion, this unique and nontraditional research
project has been a tremendous learning opportunity for both
the student and the advisor. Although sometimes challenging,
the success of this project has been the result of hard work,
careful planning, and good communication along the way.
Based on this experience, some final lessons learned are
listed in Figure 4.

The authors greatly appreciate the support of the Evonik
Degussa GmbH Feed Additives Business Unit for provid-
ing funding and facilities for this research. Additionally, the
authors would like to thank the following people for their
contribution this project: Herbert Riemenschneider, Klaus
Huthmacher, Robert D'Alessandro, Tom Thomas, Christo-
pher Roberts, John Steadman, Christoph Weckbecker, and
Karin Bartels.

1. Seay, J., M. Eden, R. D'Alessandro, and C. Weckbecker, "Sustain-
able Production of Industrial Chemical Products from Bioresources,"
Computer-Aided Chemical Engineering, 21A, W. Marquardt and C.
Pantelides (Eds.) (2006)
2. Seay, J., M. Eden, R. D'Alessandro, T. Thomas, H. Redlingshoefer, C.
Weckbecker, and K. Huthmacher, "Integration of Process Modeling
with Laboratory Experiments in Conceptual Design: Bio-based Glyc-
erol Dehydration Case Study, "Computer-Aided Chemical Engineering,
pp. 485, V. Plesu and PS. Agachi (Eds.) (2007) 1

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