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| James J. Carberry of Notre... | |
| University of California-Berke... | |
| The project approach to chemical... | |
| Test to measure the ability of... | |
| The theory of diffusion and reaction:... | |
| Indirect measurement of reaction... | |
| Interface phenomena for engine... | |
| Book reviews | |
| Waterloo program for high... | |
| A junior course in chemical engineering... | |
| Acknowledgement | |
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Front Cover
Front Cover 1 Front Cover 2 Table of Contents Page 1 James J. Carberry of Notre Dame Page 2 Page 3 Page 4 Page 5 University of California-Berkeley Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 The project approach to chemical engineering education under the WPI plan Page 12 Page 13 Page 14 Page 15 Test to measure the ability of ChE graduates in the practical application of ChE principles Page 16 Page 17 Page 18 Page 19 The theory of diffusion and reaction: A chemical engineering symphony Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Indirect measurement of reaction rate Page 28 Page 29 Page 30 Page 31 Interface phenomena for engineers Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Book reviews Page 41 Page 42 Page 43 Waterloo program for high schools Page 44 Page 45 Page 46 Page 47 A junior course in chemical engineering computations Page 48 Page 49 Page 50 Page 51 Acknowledgement Page 52 Back Cover Back Cover 1 Back Cover 2 |
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f 9 73 4wa4d 24d.,wu Waterloo Program for High Schools A Junior Course in ChE Computations Indirect Measurement of Reaction Rate The Project Approach to ChE Education Test to Measure the Ability of Seniors in the Practical Application of ChE Principles An Undergraduate Course in Interfacial Phenomena We're looking for people who are looking for the good life. The good life involves a lot of the things we've always taken for granted. Like the availability of enough food to feed an ever-growing population. A cure for disease. Thick forests. A clean environment. And the time to relax and enjoy it all. Except now we're going to have to stop looking at life through a tunnel and find ways to protect all forms of it-from our homes to the farthest corner of the earth. Because life is fragile. And its protection is a major concern at Dow. So we're looking for people with scientific, engineering, manufac- turing and marketing backgrounds who'll direct their precious talents, enthusiasm and ideas to the development of Dow products and systems for the good life. And we'll provide a dignified, motivational environment to work and grow. If you or someone you know loves life and wants to live it wisely, get in touch with us. Recruiting and College Relations, P.O. Box 1713, Midland, Michigan 48640. 'Trademark of The Dow Chemical Company DOW CHEMICAL U.S.A. Trad* EDITORIAL AND BUSINESS ADDRESS Department of Chemical Engineering University of Florida Gainesville, Florida 32611 Editor: Ray Fahien Associate Editor: Mack Tyner Business Manager: R. B. Bennett (904) 392-0881 Editorial and Business Assis;ant: Bonnie Neelands (904) 392-0861 Publications Board and Regional Advertising Representatives: SOUTH: Charles Littlejohn Chairman of Publications Board Clemson University Homer F. Johnson University of Tennessee Vincent W. Uhl University of Virginia CENTRAL: Leslie E. Lahti University of Toledo Camden A. Coberly University of Wisconsin WEST: William H. Corcoran California Institute of Technology George F. Meenaghan Texas Tech University SOUTHWEST: J. R. Crump University of Houston James R. Couper University of Arkansas EAST:G. Michael Howard University of Connecticut Leon Lapidus Princeton University Thomas W. Weber State University of New York NORTH: J. J. Martin University of Michigan Julius L. Jackson Wayne State University Edward B. Stuart University of Pittsburgh NORTHWEST: R. W. Moulton University of Washington Charles E. Wicks Oregon State University PUBLISHERS REPRESENTATIVE D. R. Coughanowr Drexel University UNIVERSITY REPRESENTATIVE Stuart W. Churchill University of Pennsylvania LIBRARY REPRESENTATIVES UNIVERSITIES: John E. Myers University of California, Santa Barbara Chemical Engineering Education VOLUME 8 NUMBER 1 WINTER 1974 FEATURES .20 4wcad .Peclie -f'973 The Theory of Diffusion and Reaction-A Chemical Engineering Symphony Rutherford Aris 44 Waterloo Program for High Schools E. Rhodes 48 A Junior Course in Chemical Engineering Computations, E. M. Rosen DEPARTMENTS 2 The Educator James J. Carberry of Notre Dame 6 Departments of Chemical Engineering University of California-Berkeley 12 Curriculum Project Approach to Chemical Engineeering Education Under the WPI Plan W. Kranich, I. Zwiebel, and Y. Ma 28 Laboratory Indirect Measurement of Reaction Rate R. D. Williams 32 Classroom Interface Phenomena for Engineers D. O. Shah 16 Views and Opinions Test to Measure the Ability of ChE Gradu- ates in the Practical Application of ChE Principles, E. C. Oden 41 Book Review CHEMICAL ENGINEERING EDUCATION is published quarterly by the Chemical Engineering Division, American Society for Engineering Education. The publication is edited at the Chemical Engineering Department, University of Florida. Second-class postage is paid at Gainesville, Florida, and at DeLeon Springs, Florida. Correspondence regarding editorial matter, circulation and changes of address should be addressed to the Editor at Gainesville, Florida 32601. Advertising rates and information are available from the advertising representatives. Plates and other advertising material may be sent directly to the printer: E. O. Painter Printing Co., P. O. Box 877, DeLeon Springs, Florida 32028. Subscription rate U.S., Canada, and Mexico is $10 per year, $6 per year mailed to members of AIChE and of the ChE Division of ASEE, and $4 per year to ChE faculty in bulk mailing. Write for prices on individual back copies. Copyright ( 1974. Chemical Engineering Division of American Society for Engineering Education, Ray Fahien, Editor. The statements and opinions expressed in this periodical are those of the writers and not necessarily those of the ChE Division of the ASEE which body assumes no responsibility for them. Defective copies replaced if notified within 120 days. The International Organization for Standarization has assigned the code US ISSN 0009-2479 for the identification of this periodical. WINTER 1974 Educator Jame J. Ga44e 4 OF NOTRE DAME Prepared by the Faculty of the Department of Chemical Engineering etW E ARE LIKE DWARFS seated on the shoulders of giants; we see more things than the ancients and things more distant, but this is due neither to the sharpness of our own sight, nor to the greatness of our own stature, but because we are raised and borne aloft on that giant mass." So wrote Bernard of Chartres in the 12th century. Jim Carberry is rather fond of that quotation. How else could he have risen, in the words of his friend Rutherford Aris, "from the low tables of Morries to the high table of Trinity, Cambridge."* BROOKLYN BEGINNINGS A NATIVE OF BROOKLYN, Jim managed to graduate from the famed Brooklyn Technical High School at which site he achieved absolute mediocrity as a single-wing halfback. "Brooklyn Tech" recalls Carberry "was somewhat more than absolutely competitive." Several classmates in- vented radar some eleven months prior to Great Britain's discovery of that toy. Carberry's qualifi- cations impressed President F. D. Roosevelt, who immediately appointed him an Apprentice Seaman in the U. S. Navy. Japanese intelligence learned of this and thus they assaulted Midway with supreme confidence. As Jim was at that moment interned at Torpedomen's School at Great Lakes, Illinois, the Japanese lost the Battle of Midway. Appropriately inspired by the quality of life aboard a U. S. Navy Light Cruiser, Carberry sur- rendered unconditionally in 1946 and, armed with the G. I. Bill, enrolled as a chemical engineering major at Notre Dame. He notes "there is nothing quite like sea duty amidst grunting 'deck apes' to inspire the lowliest of citizens to seek the highest "Citation in U of Minn. "Semisesquibiennial Wet Test Meter Award." Carberry was first and last recipient of this noble award. Now we must get on with our task-applied Chemistry. of goals-outside the Navy." At Notre Dame, he struggled with chemical engineering, played quar- terback in its intramural tackle football program (said John Lujack, "a quarterback should hide the ball, but in Carberry's case, it hides him"), helped classmate Leon Hart win the Heisman Trophy; while Leon tutored Jim in Physics I through IV. Somewhat less than inspired by the traditional chemical engineering program ("I haven't been confronted with a plate and frame filter press since I burned my copy of Walker, Lewis, and McAdams at a cocktail party in 1949"), Jim minored in English Literature and, informally, Italian opera. "I was destined, I believed, to be a Literary-Musical critic for the now deceased Brooklyn Eagle-but John Treacy saved literature and music by introducing me to chemical kinetics in my senior year. My medieval mind prompts me to envision my ultimate paper "Nth-Order Adia- batic Reaction in a Plate & Frame Filter Press." INDUSTRIAL CONTACTS IM JOINED THE EXPLOSIVES Department of the du Pont Company in 1951 as a process engineer, at which post (Eastern Laboratory, Gibbstown) he labored happily under the mentor- ship of Bill Kirst, Bob Cavanaugh, Win Johnson, and John Vyverberg. Johnson, a former student of B. F. Dodge encouraged Jim to seek a Ph.D. at Yale. At Yale Jim worked under R. H. Bretton on CHEMICAL ENGINEERING EDUCATION axial dispersion in fixed beds, talked endlessly with Jon Olson (now at University of Delaware) on topics ranging from Aquinas to Zeus, presented numerous impromptu seminars at Smith and Vas- sar Colleges, confounded B. F. Dodge by attending Barny's 8 a.m. class clad in p.j.'s, and worshipped R. Harding Bliss. "He, Harding, was a gentleman and a scholar." He feels he learned much from that Yale faculty-a logical consequence of his student days at Notre Dame under Treacy and Wilhelm, (then of the chemical engineering fac- ulty) and Burton and Hamill of Notre Dame's Chemistry Department. "One likes to think that the Professor-Student relationship be mutually re- spectful yet informal, as it was between Wilhelm, Treacy (of Notre Dame), Dodge, Bliss, Bretton, Walker (of Yale) and me." Jim returned to the Engineering Department of the du Pont Company as a research engineer at the Engineering Research Laboratory (ERL), a site famed by Chilton, Colburn, Drew, Pigford, Marshall, etc. Tom Chilton directed Carberry into catalysis: du Pont sent Jim to Johns Hopkins to take Paul Emmett's cosmic course "Catalysis" in 1959-60. "Between Paul's course and numerous discussions with Sir Hugh Taylor, I felt as would an altar-boy at the feet of Augustine and Aquinas." The four years at ERL proved most stimulating to Carberry. His mentors Von Wett- berg, Rush, and Roberts, he notes "were most tolerant and therefore encouraging." His col- leagues at ERL were most stimulating-humble Steve Whitaker, placid Forest Mixon. Marty Wendel shared his office and taught him all man- ner of things about wit and numerical analysis (namely there is a synergism there somewhere). In moments of scientific-technological terror, a fellow Brooklynite, Sheldon Isakoff, reminded Jim that "the sun never sets on Sheepshead Bay, Brooklyn." RETURN TO ACADEMIA TAKING THE CLOTH, as it were, Jim re- turned to Notre Dame in 1961 as Assistant Professor of Chemical Engineering. Dr. J. T. Banchero of Michigan had then assumed the Chairmanship of Chemical Engineering at Notre Dame and immediately set about the task of de- veloping a graduate program in chemical engi- neering. Notre Dame's president, Father Hes- burgh and then Dean of Engineering, Harry Saxe and later Norman Gay encouraged and sustained developments which created the chemical engi- neering Ph.D. program. "That indeed was a most fruitful period of maturation for our department. Without the energetic support of Father Hes- burgh, Deans Saxe and Gay, Banky, Jim Kohn, and that wise man, Ernest Thiele, naught would . . he . . helpedd Leon Hart win the Heisman trophy. have been reaped. We were, of course, not eligible for the first Cartter Report rating since we had not granted a chemical engineering Ph.D. prior to '59. Yet in the second, our first, evaluation, we were judged as "Good"-a judgment both en- couraging and challenging. I attribute this to the wise vitality of our administration, faculty, staff and students." "Since those formative years, we've retained excellent people in Luks (Minn.) and Verhoff and Smith (Mich.). One can only hope that the present Engineering College administration will be cogni- zant of whose shoulders sustain us now." "I was destined to be a literary- musical critic for the now deceased Brooklyn Eagle-but John Treacy saved literature and music by introducing me to chemical kinetics in my senior year. My medieval mind prompts me to envision my ultimate paper " 'Nth-Order Adiabatic Reaction in a Plate and Frame Filter Press'." WINTER 1974 In his twelve years at Notre Dame, Jim has directed research in Chemical Reaction Engineer- ing and Heterogeneous Catalysis. The now-uni- versally employed "swirling basket catalytic re- actor" or "Carberry Reactor," which Jim prefers to term the "Notre Dame CSTCR" was conceived and developed in 1964. The key experimental work was carried out by then Ph.D. candidate Dan Tajbl (now at Mobil Oil) who came to Notre Dame from Northwestern "a year before Ara made a move equally beneficial to Notre Dame" as Jim puts it. ACCLAIM AND ALLEGIANCE N 1965-66, CARBERRY was awarded an NSF Senior Postdoctoral Fellowship at Cambridge University, England where he thrived upon dia- logues with Danckwerts, Pearson, Davidson, Turner, Bridgwater, et al. Between "teas" he man- aged to lecture at various posts between Warsaw and Haifa. Thus it was that he, the devotee of Verdi and Puccini, found Italy. "It is asserted that I am of Anglo-Irish derivation. So be it with re- spect to my blood chemistry, but I do declare that my heart is Italian," declares Giacomo Carberri. This Spring (1974) Commendatori Carberri will again be in Italy as a Senior Fulbright Scholar at the University of Rome. In 1968, Jim received the Yale Engineering Association Award for Advancement of Basic and Applied Sciences, and he fondly hopes that in 1974 he will once again be recipient of the Interhall Football Coach Trophy at Notre Dame. For the "ole" Brooklyn Tech scrub halfback has been coaching intramural eleven man contact ("col- lision") football on the Notre Dame campus for over a decade. Says he, "oh, for the pre-Ara days when I could boast as being the only winning foot- ball coach on campus. But, alas, no threat to Ara am I." Off-season, Carberry preoccupies himself with research in surface catalysis in association with his solid-state physicist colleague George Kuczyn- "It is asserted that I am of Anglo-Irish derivation. So be it with respect to blood chemistry. But I do declare that my heart is Italian. i ~t: fl " I*r* J *r Ik' Carberry and his daughters. ski and teaching both graduate and ("most im- portantly") undergraduate Reaction Engineering. He is now co-editor of Catalysis Reviews and a member of the U.S.-Soviet Working Group on Catalysis. He harbors rather firm views regarding the future of Chemical Engineering and society in general. A Stevensonian Democrat, in typical eclectic fashion, Carberry is a devoted admirer of William F. Buckley, Jr. and his National Review. Given his studied dedication to Aquinas, Dante, and Maritain, the seeming paradox may be il- lusionary. He believes in civilized society, which signifies civilized discourse amongst civilized men, phrased in civilized form and spirit. "I am the enemy of the 'you know' generation, who are poised before bronze calves, mesmerized by a cacophony, miscoined by morons and idiotic sooth- sayers as meaningful, relevent, and true because it feels right." Explaining how he views chemical engineer- ing, Carberry relates "Olaf Hougen put it all in perspective-our roots reside in chemistry-at a particular stage the Hougen's, McAdam's, etc. put order into transport processes. Now we must get on with our true task-applied chemistry. This may well mean divorce with respect to general engineering. Che sara', sara'. Remember those shoulders which sustain us all." D CHEMICAL ENGINEERING EDUCATION �~ L .' Find out if the chemistry's right. At Du Pont, the best chemistry is people chemistry. Anything can be achieved if you have the right people and they talk to each other. So we look at you as much as at your grades. We look for compatibility as much as talent. And that goes for engineers and chemists as well as business students. If you want to find out what fields An Equal Opportunity Employer M/F have openings, what states you can work in and more, meet with the Du Pont recruiter when he comes to your campus. Or if you've already graduated and have experience, write Du Pont direct, Room N-13400, Wilmington, Del. 19898. And as you know by now, we're equally interested in women and men of any color. The chemistry is what counts. WINTER 1974 iFJ department BERKELEY C. JUDSON KING, THEODORE VERMEULEN and JOHN M. PRAUSNITZ UnlirersitU of California Berkeley, California THE CHEMICAL ENGINEERING Department at the University of California's charter campus celebrated its 25th anniversary in 1971-72. Starting strong but small just after World War II, with both The M.S. and the Ph.D. programs pre- ceding establishment of the B.S. degree, the de- partment has grown to he one of the largest units among U.S. universities. Today there is a faculty of 20 full-time professors, a graduate student body numbering about 130, and 30 to 40 seniors gradu- ating annually. The number of Ph.D.'s graduating in 1971-72 was 22, and in the same year there were 20 M.S. graduates. Several distinctive features characterize Berk- eley chemical engineering-beyond its relatively recent genesis and its physical location in the Athens of the West. One characteristic is its close affiliation with chemistry; in fact, the Depart- ments of Chemical Engineering and Chemistry make up the College of Chemistry at Berkeley, one of very few such college structures. As another feature, Berkeley's department devotes a larger fraction of its effort to the graduate program than is possible in most schools. The M.S. shares center- stage with the Ph.D., and both degrees require a thesis. To a great extent graduate education is built around individual tutorial instruction, car- ried on for the most part through joint student- faculty research and design. The spectrum of top- ics of interest and investigation represented in the department is extremely wide, ranging from ap- plied to fundamental. Chemical process design and engineering are emphasized equally with basic engineering science. DEPARTMENTAL HISTORY At Berkeley, chemical engineering by that name began in the 1940's but had been anticipated Berkeley's Campanile dominates the campus skyline and overlooks San Francisco Bay-an Ivory Tower but not an academic refuge. from the time the University was founded in 1868. Frederick Cottrell, Cal's first true chemical engi- neer, invented electrostatic precipitation here around 1906. In 1912, Gilbert N. Lewis, as in- coming Dean of the College of Chemistry, insti- tuted a chemical technology major, subsequently directed by Merle Randall. As of 1942 an inter- departmental Graduate Group offered the M.S. degree in chemical engineering. September 1946 marked the start of formal undergraduate instruc- tion, offered in the College of Chemistry with complementary work in the College of Engineer- ing. Philip Schutz, the program's first unofficial chairman, LeRoy Bromley and Charles Wilke formed the charter group. Succumbing soon to a tragic illness, Schutz was replaced by Theodore Vermeulen. This group was then joined by Donald Hanson and Charles Tobias in 1947, completing CHEMICAL ENGINEERING EDUCATION the initial staff. The new program rapidly gained recognition, achieving formal approval of the Ph.D. program (1947) and B.S. program (1948), changing the departmental name to Chemistry and Chemical Engineering (1949), creating the sub-departmental Division (1952), creating a sep- arate Department (1957), renovating and fully occupying Gilman Hall (1963), and subsequently expanding into a major portion of Lewis Hall (1965). FACULTY GROWTH W ILKE SUCCEEDED Vermeulen as Chair- man in 1953, and led a rapid expansion in numbers of graduate students and faculty, to serve the fast-growing needs of the State of Cali- fornia. Eugene Petersen (1953) and John Praus- nitz (1955) were the next of the present profes- sorial staff to arrive, and were followed by David Lyon who had been with the Low Temperature Laboratory of the College, Alan Foss (1961), Simon Goren (1962), Edward Grens (1963), Jud- son King (1963), John Newman (1963), Robert Merrill (1964), Michael Williams (1965), Robert Pigford (1966), Scott Lynn (1967), Alexis Bell (1967), Mitchel Shen (1969), and Lee Donaghey (1970). Thomas Sherwood, after two previous visiting appointments here, transferred perma- nently from M.I.T. in 1970. In 1963, Hanson suc- ceeded Wilke as Chairman, followed by Tobias (1967-72) and King (1972-present). Activities of the department are extended and supported by a number of other professionally active engineers, including Lecturers E. Morse Blue, Gerhard Klein, Arthur Morgan, Rolf Muller, Charles Oldershaw, and Otto Redlich. David Templeton, dean of the College of Chemistry, and Douglas Fuerstenau, Chairman of Materials Sci- ence and Engineering in the College of Engineer- ing, participate often. Enrichment of the depart- ment's work also comes from strong ties with the Lawrence Berkeley Laboratory and the Sea Water Conversion Laboratory. Students and faculty meet at the coffee hour preceding the de- partment's weekly Colloquium. Visiting professors have included Shinichi Aiba (To- kyo), Chandler Barkelew (Shell), Thomas Baron (Shell), Andre Bellemans (University of Brussels), Thomas Chilton (DuPont), Lewis Etherington (Esso), Ulrich Franck (Karl- sruhe), Robert Finn (Cornell), Robert Greenkorn (Pur- due), Norbert Ibl (ETH Zurich), Lewis Iscol (Chevron), Robert Johnk (San Jose State), Adriaan Klinkenberg (Royal Dutch), Herman Mark (Brooklyn Poly), John Ornea (Shell), Giuseppe Parravano (Michigan), Henrick Van Ness (Rensselaer), and Fumitake Yoshida (Kyoto). The work of the department has been sup- ported generously by the State of California, Fed- eral agencies and several research foundations. Present industrial donors include the DuPont Company, General Electric Company, Shell Oil, Standard Oil of California, Exxon Companies, Union Carbide Corporation, Stauffer Chemical Corporation, Dow Chemical USA, Gulf Oil, Mobil Oil, and Union Oil. Many members of the faculty have received awards from AIChE, ACS, ASEE or the Electro- chemical Society. In addition, three are members of the National Academy of Sciences and two are members of the National Academy of Engineer- ing. BERKELEY PHILOSOPHY A STRONG TENET of the Berkeley faculty is that education in chemical engineering en- Several distinctive features characterize Berkeley chemical engineering-its close affiliation with chemistry .. . it devotes a large fraction of its effort to the graduate program ... and it puts the M.S. and the Ph.D. on center stage requiring theses for both degrees. WINTER 1974 ables a graduate to undertake any of an ex- tremely wide and steadily expanding range of endeavors. This is reflected in the broad scope of research and technical interests represented in the department, by the wide variety of courses and seminars, and by the diverse occupations filled by past graduates of the department: process engi- neers, electrochemical engineers, systems engi- neers, food engineers, biochemical engineers, ex- tractive metallurgists, pharmaceutical-device en- gineers, environmental engineers, nuclear engi- neers, experts in pure sciences, and managers of technical enterprises. The program at Berkeley is designed to give the student extensive competence and understanding, with abilities to develop fur- ther knowledge and insight with minimal difficulty in whatever specialized area he may enter. In 1970, option areas were made available in the undergraduate program, offering supplementary study in chemistry, applied physics, systems anal- ysis and applied mathematics, materials and mole- cular engineering, space systems, earth-ocean- atmospheric sciences, environmental balance, ap- plied biology, food resources and processing, busi- ness enterprise, or science education. Research and project engineering are the pri- mary vehicles for tutorial instruction, which aims at developing the student's self-reliance, initiative, and technical maturity. The underlying principle is that a student learns best the things he does himself rather than those he hears second-hand. "Research" is interpreted in a broad sense. In recent years many theses have dealt with process synthesis, development, and design. The common thread of exploration in all these areas, as well as for research on more fundamental problems, is Mysteries of catalysis are the focal point for research by professor Eugene Petersen and graduate student Daniel Kahn. "Research" is interpreted in a broad sense . .. In recent years many theses have dealt with process synthesis, development and design. that the student undertakes a truly original prob- lem-something clearly new, for which the answer has not already been determined. The depart- ment's attention to chemical process engineering as well as to fundamentals is reflected in several problem-oriented graduate courses, and in its focus upon chemical process engineering (to- gether with transport phenomena and physico- chemical principles) in the comprehensive pre- liminary examination for Ph.D. candidates. Emphasis upon developing the student's ability to work on his own is also reflected in the definitive Ph.D. oral qualifying examination. Here the student presents and defends a self-generated "proposition" for a significant re- search advance or process improvement. The proposition cannot be related to his thesis research; it is conceived on his own without faculty help, although advance criticisms may be made by his qualifying committee chairman. This examination provides a profoundly maturing experience, and when completed gives the student greatly increased self-confidence and independence of mind for further engi- neering studies which culminate his doctoral thesis. The Berkeley Ph.D. program has proved to be a major supply of teachers for other universities. A recent count shows that 39 U.S. professors have received a Ph.D. in chemical engineering from Berkeley, most of them within the last 10 years. These include: Richard Alkire (Illinois), Byron Anshus (Delaware), Douglas Bennion (UCLA), John Berg (Washington), Robert Blanks (Michigan State), David Bonner (Texas Tech), Ray Bowen (Wisconsin), Robert Chambers (Tu- lane), Thomas Chapman (Wisconsin), Winston Cheh (Co- lumbia), Peter Clark (Virginia Poly), Milton Davis (South Carolina), John Duffin (Naval Postgraduate School), Charles Eckert (Illinois), John Friedly (Rochester), Joe Goddard (Michigan), Earl Gose (UI Chicago Circle), Rob- ert Gunn (Wyoming), James Han (Michigan), Gordon Harris (Tulane), Thomas Hicks (UCLA), Jacob Jorne (Wayne State), William Krantz (Colorado), Robert Madix (Stanford), Thomas Massaro (Wisconsin), Robert Mer- edith (Oregon State), Reid Mil'er (Wyoming), Alan Myers (Pennsylvania), John O'Connell (Florida), John Powers (Michigan), Clayton Radke (Penn State), Peter Rony (Virginia Poly), Orville Sandall (UC, Santa Barbara), Fred Shair (Caltech), Lloyd Spielman (Harvard), Darsh Wasan (Illinois Institute of Technology), Henry Weinberg (Caltech), Douglass Wilde (Stanford), and William Wilcox (Southern California). CHEMICAL ENGINEERING EDUCATION A corresponding list of Ph.D. graduates teach- ing at foreign universities would number another 15-20. Also a significant number of Cal's B.S. and M.S. graduates are serving on university faculties. These include, among others: Philip Becker (Penn State), Robert Brodkey (Ohio State), Sunny Chan (Caltech), Bruce Gates (Delaware), K. R. Hall (Virginia), George Homsy (Stanford), Marc LeMaguer (Alberta), Octave Levenspiel (Oregon State), R. L. Merson (UC Davis), Zuhair Munir (UC Davis), Ken Nobe (UCLA), Channing Robertson (Stanford), Robert Sani (Illinois), L. E. Scriven (Minnesota), J. D. Seader (Utah), Oktay Sinanoglu (Yale) and Steven Whitaker (UC Davis). Graduate student Daniel Kahn deals with the mysteries of catalysis in his research at Berkeley. The department encourages its own bachelors to take their graduate work at other schools, based upon the principle that students should experience more than one approach to subject matter and to problem-solving techniques. RESEARCH PROGRAMS BERKELEY'S RESEARCH activity and cap- ability encompass an ever-evolving range, as twenty full-time faculty and four of the part-tim- ers in chemical engineering continually reassess the needs and opportunities for significant innova- tive work. The fields of research listed in the ac- companying table include few surprises, as they almost all show a substantial relevance to eventual practical applications in physical preparation, sep- aration, or chemical reaction, with respect to sys- tems of multicomponent and or multiphase char- acter. Of the ten main areas, the first five are fields where Berkeley has an exceptional intensity of effort, compared with the general average, and the second five can be considered as nearly uni- versal. What "master concepts" underlie this research activity? The goal already cited-intellectual growth by the student into the status of a fully independent professional-is implemented by a number of operational principles, proven by time and applied with flexibility. First, when the interests of different staff members overlap or coincide, collaboration between them often oc- curs. Second, the student's growth is measured by ever-in- creasing control over the research he (or she) conducts. A Ph.D. student in his first year typically does about 20% of the innovation and 80% of the physical and mental work involved in his research project, the faculty super- visor providing the remainder directly or indirectly. In his last year, the student does 80% of the innovation and 95% of the physical and mental work. A student engaged in research will typically spend two to four hours each week with his faculty supervisor. However in the period when the dissertation is being written, reviewed, and re- vised, many additional hours of intense discussion occur. Third, graduate students consult widely with faculty members other than their immediate research supervisor, with enough opportunity to learn from all of them. They are expected in due time to become more expert than their mentors. Fourth, although of course the professors are expected to provide the largest primary input into the communica- tion chain, graduate students are likely to learn even more from one another than they learn directly from the faculty. Fifth, the program emphasizes breadth as well as depth. Graduate students attend a variety of courses and seminars, including those in neighboring departments, and frequently carry out a second brief research project with a faculty member other than their thesis advisor. Sixth, the student normally is spurred to complete his master's degree within 12 to 24 months, or his doctorate in 36 to 54 months, on the basis that graduate study is preparation for a career and not a career in itself. WIDER AFIELD Although the campus is most often identified by its 310-foot Campanile, Berkeley is no ivory tower but a bustling reflection of the world at large. Its scenic setting overlooking San Francisco The department's attention to chemical process engineering as well as to fundamentals is reflected in several problem-oriented graduate courses, and in its focus upon chemical process engineering. WINTER 1974 Bay provides a multitude of recreational and so- cial opportunities for students and faculty. Be- sides the proximity of supportive industry and government laboratories, there are all the cultural attractions befitting this major urban center, as well as opportunities for hiking and mountaineer- ing in the Sierra Nevada, sailing in the Bay, other participatory and spectator sports of all kinds, and finally a living laboratory of sociological, po- litical, and philosophical "ferment" for which Berkeley has attracted international attention. D RESEARCH ACTIVITIES AT BERKELEY Process Development, Design, and Optimization Calculation Techniques and General Strategy. Systematic procedures for synthesis, arrangement, and improvement of processes. Computation strategies to define optimum designs. Computer-implemented simulation of large proc- ess systems and their individual components. (Foss, Grens, King). Process Engineering and Conceptual Design. Development and analysis of case problems for instruction. Desalination of sea water by processes involving evaporation, ion ex- change, reverse osmosis, freezing and/or foam fractiona- tion. Waste utilization through microbial processes and other techniques. Hydrogenation and extraction of coal and oil shale. Electro-refining of metals. Cryogenic separa- tion, including isotope recovery. (Bromley, Grens, King, Klein, Lynn, Lyon, Sherwood, Tobias, Vermeulen, Wilke). Pollution Control. Recovery of solvents from vent gases by adsorption. Catalytic treatment of automobile-exhaust components. Removal of SOx and NO, from stack gases. Water pollution abatement by solvent extraction, foaming, coalescence, process modification and other approaches. Radioactive waste disposal. (Bell, Bromley, Goren, King, Klein, Lynn, Petersen, Pigford, Prausnitz, Sherwood, Vermeulen). Biochemical, Food and Biomedical Applications Techniques for dense culture of bacterial cells, with ap- plications to fermentation processes, vaccine production and solid-waste utilization. Reactions involving immob- ilized enzymes. Food processing by freeze-drying, freeze- concentration, and other dehydration methods. Polymers for biomedical applications, including synthesis by glow discharge. Fluid dynamics, structure, and susceptibility to damage of blood under flow conditions. (Bell, King, Shen, Wilke, Williams). Polymeric and Inorganic Materials Polymer Systems. Measurement and theory of viscoelastic- ity of solutions, melts, and multiphase polymer systems. Thermodynamics of block copolymers and polymer solu- tions. Polymerization kinetics. (Merrill, Prausnitz, Shen, Vermeulen, Williams). Inorganic Solids. Determination of solid-surface lattice structure, composition, and reactivity. Crystal growth. Of the ten main areas, the first five are fields where Berkeley has an exceptional intensity of effort, compared with the average, and the second five can be considered nearly universal. Optical, electronic, and elastic properties of solids. Thin- film production and epitaxial growth. (Donaghey, Merrill). Cryogenic Engineering P-V-T behavior, separations, and heat exchange in the liquefaction of air, hydrogen, and helium. Adiabatic de- magnetization with large-volume magnetic fields. Physical properties of fluids and solids at high pressure and low temperature. Low-temperature mechanical and dielectric relaxation and other physical properties of polymers. (Lyon, Prausnitz, Shen). Electrochemical Engineering Development and Design of Electrolytic Cells. Electrode processes-geometry, current distribution, limiting cur- rents, gas evolution. Electro-chemical shaping and finish- ing of metals. Production of surfaces and fibers by elec- trolysis. (Lynn, Merrill, Muller, Tobias). Energy Storage and Conversion. Batteries and fuel cells. Electrolysis in nonaqueous ionizing solvents. (Grens, Tobias). General. Electrostatic gas-solid and liquid-solid separations. Continuous electrophoresis or electrochromatography in liquids. Electronic and ionic transport in inorganic solids. Corona- and glow-discharge devices for measurement of solid-aerosol areas and size distributions. (Bell, Donaghey, Hanson, Tobias, Vermeulen, Wilke). Chemical Process Dynamics and Control Control-systems development for industrial-scale re- action and separation systems. Dynamic models for large scale systems including fixed-bed reactors and distillation systems. Response mode-based synthesis methods for con- trol system configurations. (Foss, Grens). Kinetics and Catalysis Heterogeneous Catalysis. Molecular-scale gas-solid be- havior over extreme pressure ranges. Chromatographic reactors. Reactor dynamics and particle configuration. Process applications. (Bell, Merrill, Petersen). Simultaneous Heat Transfer, Mass Transfer, and Chemical Reaction. Combustion. Particle deflagration. Reactor engi- neering. Kinetics of phase transitions. Photochemical re- actor design. Plasma chemistry. Homogeneous catalysis. Kinetics and mass transfer in microbial growth. (Bell, Donaghey, Grens, Merrill, Petersen, Pigford, Sherwood, Vermeulen, Wilke). (Continued on page 41.) CHEMICAL ENGINEERING EDUCATION WE ENCOURAGE JOB HOPPING. In fact at Sun Oil we've just adopted a new system that promotes it. * Internal Placement System. * Here's how it works. Say you're in Production and you decide to take a crack at Marketing. Next opening in Marketing we'll tell you. You can apply and be considered. First. You have freedom to experiment and move around at Sun. You learn more and you learn faster. * Why do we encourage job hopping? Because we happen to believe our most valuable corporate assets are our people. The more our people know, the stronger we are. * Now-you want to know more? Ask your Placement Director when a Sun Oil recruiter will be on campus. Or write for a copy of our Career Guide. SUN OIL COMPANY, Human Resources Dept. CED. 1608 Walnut Street, Philadelphia, Pa. 19103. An E l Opportunity EOC r M An Equnl Opportunity Employer M/F curriculum THE PROJECT APPROACH TO CHEMICAL ENGINEERING EDUCATION UNDER THE WPI PLAN W. L. KRANICH, I. ZWIEBEL, and Y. H. MA Worcester Polytechnic Institute Worcester, Massachusetts 01609 FOR MANY YEARS the faculty and students at Worcester Polytechnic Institute have been aware of the great educational value of inde- pendent projects. This awareness has been fos- tered by National Science Foundation Undergrad- uate Research Participation grants, senior theses (optional in many departments), use of under- graduates as assistants and participants in sup- ported graduate research projects, and special programs such as the Clean Air Car race. Projects have, in fact, become the cornerstone of the newly developed educational innovation, the WPI Plan. Unlike the usual experiments in education where one variable is altered at a time, this is a total commitment with changes in just about every aspect of the college. The central theme of the program is that the student is pre- pared for his professional life by an educational program which emphasizes his independence and develops confidence and self-reliance through a strong element of self-education. There is no formal curriculum and the criteria for graduation are intended to demonstrate the student's com- petence to enter his or her chosen profession. The basic criteria are given in Table 1. Table 1 GRADUATION REQUIREMENTS UNDER THE WPI PLAN 1. Satisfactory completion of an independent project in the major field 2. Satisfactory completion of an independent project which relates society and technology 3. Successful performance on an examination which tests the competency of the student to enter his profession 4. Demonstration of sufficient competence in a secondary field Students entering as freshmen during the first two years of operation were permitted to choose either this program or traditional departmental requirements (curriculum, minimum grade-point average, minimum credits). During the second year more than 95% of the entering freshmen elected the WPI Plan. This encouraged the faculty to eliminate the traditional option one year earlier than planned. As a result, during the current year the entire freshman class entered under the new program. In addition to the new graduation require- ments there are other innovative features of the Plan. During each of four or five seven-week terms the student concentrates on three subject areas (rather than studying five or six subjects for a 14-week semester). In the planning of a student's program the key roles are played by the student himself and by his academic advisor. De- partments provide a home base for the faculty, but need not be of central importance to the stu- dent. So long as the student can find an advisor willing to work with him in his desired area, and that advisor can assemble a faculty committee willing to examine the student's competence, there are no constraints on the major area of the stu- dent. While we expect that for the next several years at least, most students will choose to major in the conventional fields of science and engineer- ing, we expect to find some who will want a major in such areas as biomedical engineering with an The central theme ... is that the student is prepared for his professional life by an educational program which emphasizes his independence and develops confidence and self-reliance through . .. self education. There is no formal curriculum. CHEMICAL ENGINEERING EDUCATION emphasis on the chemical point of view, or man- agement engineering with concentration on the management of chemical plants. Naturally it will be one function of the advisor to discourage the student from too narrow specialization, but in the end it will be the student's choice. PROJECT ORIENTED PROGRAM INDEPENDENT PROJECTS are at the heart of the new program. The projects may be car- ried out in groups or individually, as research or independent study. Up to about 25'/ of a stu- dent's activities at WPI will be taken up by such projects; some will be chosen to meet the degree requirements (i.e., qualifying type), while some will be exploratory or preparatory to the qualify- ing projects. They may be executed on campus or at an off-campus site, but still under full faculty supervision. Past experience shows that in chem- ical engineering, far more than half of these proj- ects will be of experimental, research or develop- ment type as contrasted to design projects. While there has been considerable experience at WPI in project work of the on-campus, senior- thesis type, until recently we had little operating know-how on group projects, particularly those concerned with off-campus, real-world problems of government and industry. The chemical engi- neering department has participated in two major pilot projects of this type-one the Environ- mental Systems Study Program (ESSP) spon- sored by the Sloan Foundation and the Environ- mental Protection Agency, and the other an off- campus internship center at the U.S. Army Natick Laboratories in Natick, Mass. One of the authors of this paper (I. Zwiebel) was instrumental in developing the former program and another Y. H. Ma received his bachelor's degree from National Taiwan Uni- versity, his master's degree from Notre Dame and his doctorate from M.I.T. (in 1967) all in Chemical Engineering. He has taught at WPI since 1967. His research areas include diffusion in porous solids and mathematical simulation. (left) W. L. Kranich received his B.S. in Chemical Engineering from the University of Pennsylvania and his PhD. (in 1944) from Cornell Uni- versity. He taught at Princeton University before coming to Worcester Polytechnic Institute in 1948, and has been Head of the Chemical En- gineering Department since 1958. His current research interests are in reactions on molecular sieve zeolite catalysts and process development. (left below) I. Zwiebel did his undergraduate work in Chemical Engineering at the University of Michigan and his graduate study at Yale, where he received his doctorate in 1961. He has had industrial experience with duPont and Esso, and has been on the WPI faculty since 1964. His research efforts are concentrated in the fields of adsorption and ap- plied mathematics. (right below) author (Y. H. Ma) played the key role in the de- velopment of the latter and serves as Internship Center Director. PROJECT EXAMPLES N THE REMAINDER of this paper we present examples of student projects of the research type-associated with on-going sponsored re- search at WPI-and of the group, off-campus type under the ESSP program and the Natick Internship Center. Both underclassmen and seniors have success- fully joined teams of graduate students and car- ried out individual projects on a solid waste con- version program sponsored by EPA. The overall effort is concerned with conversion of cellulosic and other organic wastes to useful oil by hydro- genation. One undergraduate studied the effects of some of the process variables. Another devel- oped an analytical technique for characterizing the product. A third, using computer-aided design techniques, developed a flow sheet and preliminary cost data for a projected large scale application. WINTER 1974 A NASA-sponsored research program for long-duration space flight is concerned with con- version of human wastes into edible sugars via formose synthesis. One undergraduate looked into the effect of different catalysts. Another studied the fermentation of formose sugars with the objective of protein generation. A third at- tempted to explain and characterize the observed instabilities of the continuous stirred tank reactor in which the formose synthesis occurred. The educational value of undergraduate proj- ects cannot always be measured in terms of posi- tive research results. In one instance an under- graduate study of the bonding between absorbate species and adsorbent sites (associated with an EPA-sponsored air pollution control project) was not very productive. Infra-red absorption spec- troscopic techniques with KBr pellets containing varying amounts of the absorbent were used. The observed results were inconclusive. While the in- terpretation of I.R. spectra is a very complicated skill, the student in consultation with a faculty member of the chemistry department did a very fine job analyzing his meager spectra. However, the student exhibited a case of stubbornness. In the literature, only a very few instances were gas- solid interactions successfully investigated by KBr absorption techniques-most researchers prefer the reflectance methods. The student refused to Past experience shows that in chemical engineering far more than half of these projects will be of experimental, research or development type as contrasted to design projects. try out this technique, stubbornly insisting that a way shall be found to use the pellet technique. At the end, in light of the absence of results, he had to concede that research should not be a sledge- hammer operation. The student enjoyed his ex- periments and was satisfied by his experiences; he went on to graduate school to pursue a career in biochemical engineering. A more successful example of a research proj- ect is illustrated by a sophomore, who tried en- gineering research because he never had exposure to large scale facilities. He was facing a choice between a career in chemistry or chemical engi- neering. We teamed him up with a Ph.D. candi- date who was studying the dynamics of adsorption in fixed bed columns. This sophomore was to be in charge of the desorption experiments which had to be carried out before the next adsorption could be run. In part emulating the graduate student, the sophomore developed a comprehensive experi- mental schedule for the desorption runs, devoted many night-time hours to gather the data, ana- lyzed his results, and developed sufficient results to warrant publication. In this case the learning and direction were very positive. He was gradu- ally, through participation, introduced to chemical engineering. He has since graduated at the top of his class and gone on to graduate school in chem- ical engineering. PROJECTS CONTRIBUTE TO SOLUTIONS THE ENVIRONMENTAL SYSTEMS Study Program, sponsored by the Alfred P. Sloan Foundation, was designed to develop team inter- disciplinary projects in conjunction with indus- trial governmental sponsors. The intent was not to teach the subjects of the other disciplines rep- resented on the team to the chemical engineers, or vice versa; it was hoped that students would learn to communicate with specialists from other areas. It was expected that each person working in his own field could contribute to the combined solu- tion of complex real problems. We have had twelve such projects in the past two years. An ex- ample in which the chemical engineering contribu- tion was quite significant was the Salem Harbor Project. Salem Harbor power generating plant is lo- cated in the immediate vicinity of resort towns and is frequently influenced by local meteorolog- ical phenomena, i.e., strong but short range winds off the ocean. The growth of the plant has in recent years created an environmental concern. The environmental influences during transient peak-load operation of the plant were to be evalu- ated. First the concepts of transient operations had to be brought across to the students. Then, fa- miliarization with the power plant process had to be covered. This brought into focus the stoichio- metric calculations. Initial instinct was to measure SO, emissions. However, the student team quickly realized that SO, emissions are directly proportional to fuel feed rate, and in no way do they represent unique pollution problems during the transient opera- tions. CHEMICAL ENGINEERING EDUCATION While ... most students will choose to major in the conventional fields of science and engineering, we expect to find some who will want a major in such areas as biomedical engineering with an emphasis on the chemical point of view, or management engineering with concentration on the management of chemical plants. Next, they zeroed in on NO, measurements. The various analytical procedures were evaluated; sampling and remote analyses were compared with continuous instrumental techniques. They selected instruments, chose sampling locations, and ran preliminary measurements under steady state operating conditions. Then the variation of NO, concentration with operating load was ob- served. A plot of air-to-fuel ratio versus time revealed that during the transient phase the plant operates in a fuel-rich regime. This prompted a switch to the measurement of CO, unburned hydrocarbons, and particulates. The final in-depth design will focus upon im- proved precipitator operating conditions, the in- stallation of some sort of scrubbing device to re- move the NO, which is in excess of emission standards, the establishment of an operating pol- icy which will maintain reasonably uniform con- ditions in the combustion chamber, and the re- placement of existing (old) control devices with equipment that will quickly respond to the pri- mary variables. The systems design will consider the power generation facilities of the entire plant, consisting of four units, and the entire New England Power System, and will attempt to establish a control policy so as not to burden the vicinity of the Salem area. Also the development of a regional simulation program, starting with one of EPA's air quality display models, is planned. In industrially sponsored projects the lack of effective communications between the involved personnel may create some problems. Occasion- ally, the liaison-advisors assigned to work with the students are not involved in the project de- velopment stages. Then, if the educational objec- tives are not clearly specified, some of these super- visors may view the presence of the students with suspicion. In one instance when this happened, one meeting with the involved principals on an ESSP project was sufficient to re-establish a fav- orable environment to continue the project. In an- other instance, however, on a project dealing with a sensitive water pollution problem, comments were made to the students by an uninformed engi- neer insinuating that the students were planted for espionage purposes. Rather than wasting the students' time while potentially extensive negotia- tions were being held to clear up a misunderstand- ing, we decided to terminate the project. The stu- dents were assigned to another problem. One of the unique features of the Plan is the establishment of Internship Centers where WPI students can go for off-campus project experience. The WPI Internship Center is different from the commonly known cooperative program. While the industrial experience gained by the students through the co-op programs is undeniable, it must he recognized that one of the chief purposes is to extend financial aid to the student. The Colleges involved have little or no control of the students' on-site activity. On the other hand, the WPI In- ternship Center emphasizes the educational merit of the programs which are closely related to the student's technological interest. The students work on problems of their own choice at the off- campus Internship Center in cooperation with site personnel and under the overall supervision of WPI faculty as site directors. CONTACT WITH GOVERNMENT RESEARCH N INTERNSHIP CENTER was established at the U.S. Army Natick Laboratories which accommodated six groups of students for the year 1971-72. The number of students in each group ranged from one to three. All were chemical en- gineering majors except one group of two mre- chanical engineers. Two typical projects are de- scribed in the following: (Continued on page 10.) WINTER 1974 views and opinions Test to Measure the Ability of ChE Seniors In the Practical Application Of ChE Principles E. C. ODEN Mississippi State University State College, Mississippi The following test was first given to our plant design students. It was meant to be part of a rou- tine test toward the end of the semester in the practical application of ChE principles to the lay- out of a typical process flowsheet. When I re- viewed the answers to the problem, it was very discouraging to have to accept the fact that our students had made so very many unexpected mis- takes. It caused me to wonder how ChE seniors in other schools compared with ours in the prac- tical application of chemical engineering princi- ples. It occurred to me to ask other schools to give this same test, if their professors would cooperate. Copies of the same test were submitted to sev- eral schools having ChE departments in hopes of making comparisons of our students with theirs. The professors were promised that I would not use school names or student names, if the test scores were analyzed and published. Thus, no effort is made to compare schools or individual students in this publication. The test presented below was given to the schools that agreed to the proposal. OPEN BOOK PORTION OF TEST Complete the process flowsheet that has been started having been given the following data: Compound A has physical properties comparable to isobutane. Compound B has properties compar- able to hexane. The compound B is unsaturated but when combined with A and I.1, IIi ii "n over a nickel complex catalyst, a saturated compound AB is formed with traces of methane and about 2( tar based on total weight of A + B fed. Reactions may be represented: A(4 moles) + B(I mole)-> AB unsaturated + A(excess) AB unsaturated + H.(4 moles)-> AB saturated + 3 moles H. + 2% tar The tar boils at about 450�F and 35 to 40 psia. The reaction is exothermic having about 100,- 000 Btu lb mole of AB formed. Compound AB has properties equivalent to decade. Assume impurities in the hydrogen should not build up above 10'/ before being bled off and there is a constant supply of make up hydrogen avail- able as well as A + B. Assume product AB is to be 95'/; or greater purity. Showi approximate temperatures, pres- sures and approximate compositions directly on vessels on the flow'sheet you complete. Take ad- vantage of utilities produced where possible. Re- flux ratios on tower or towers may be taken as 1 /1. Approximately 100 students took the test, in- cluding all schools. The names of schools and names of students are not given to avoid em- barassing any schools or students. The test results are summarized below. This was given as an open book test and equi- librium data or other needed data were available. SUMMARY OF ANSWERS 1. 23% of the students used a pump to take the 25 psia gas from the holder and charge to the reactor at 700 psia. 2. Of those that used compressors to move the gas from My analysis of the results reveals a very serious weakness on our part as professors in teaching our students to think. CHEMICAL ENGINEERING EDUCATION pllb FEEDSTOCKS REACTOR DISENGAGING EQUIPMENT FRACTIONATOR - . t 17r% H I%CO4 25PSIA IOOIA 100-F FINISHED STREAMS GAS FUEL 400 PSIA 140'F o00 PSIA STEAM \ C -.FI, A q> SUPPORT CONDENS TE ~'Q - OENC --- 11- 00F COILS L SOO-F b660 PSIA 650 PSIA 22. 60% failed to place any type product coolers on prod- uct lines to storage vessels. 23. 90% failed to show any temperature or pressures rec- ommended for storage vessels. 24. Only three students took into consideration that it would be better to store the tar at elevated tempera- ture. 25. Only about 10% of the students established the correct design basis for the feed to the reactor-the moles H., should be in the ratio 9 moles per 1 mole of the sum of the inerts-10% inerts in the total Hydrogen feed. 26. Obviously, with the knowledge of the simple mistakes made as mentioned, it would be too much to expect them to know how to process the #1 column overhead in a manner to obtain the proper recycle compositions. Some students did select the correct type reboilers and similar considerations. Process Flowsheet. TEACHING OUR STUDENTS TO THINK 25 psia to 700 psia, 69% failed to use a knockout drum ahead of the compressor. 3. 24% of the students used compressors to take liquid "A" at 100 psia and discharge to reactor at 700 psia. (Note: Equilibrium temperature and pressure relation- ships of "A" and "B" could have been consulted, if in doubt, as to being a liquid or a gas.) 4. 36% of the students used no pump to take liquid "A" at 100 psia to reactor at 700 psia. 5. 28% of the students used compressors for moving liquid "B" at 20 psia to reactor at 700 psia. 6. 26% took liquid "B" at 20 psia directly to reactor at 700 psia without any power mover. 7. 20% used no preheater of any type to go from the vessels as indicated to reactor at 10000F. 8. 12% vaporized liquids then compressed to 700 psia with a compressor. 9. 46% preheated with 6000F steam only to reach 10000F feed temperature entering the reactor. 10. 80% failed to recycle steam condensate to reactor. 11. 68% showed no recycle H., from flash vessel to reactor. 12. 82% showed no recycle of product "A". 13. Of those that did recycle hydrogen, only 10% took advantage of the pressure of gas off the flash vessel and returned it to one of the higher pressure stages of the compressor. 14. 80% failed to quote any temperature or pressure what- ever as requested on the first tower. 15. 60% failed to show any reflux for tower #1. 16. 40% failed to take bottoms from tower #1 to tower #2. 17. 30% failed to use any reflux on tower #2. 18. Of those that had correct feed to the tower #2, 60% failed to select pressure and corresponding temperature correctly on reflux drum to #2. 19. 80% failed to give proper temperature and pressure for top of tower #2. 20. 42% failed to provide a reboiler of any type for tower #2. 21. 70% failed to use correct transfer equipment for tower #2 products where correct feed to tower was used. There were many other mistakes, too numer- ous to mention collectively, but it was extremely revealing just how little our students have learned to think. It was not a surprise to learn that many Some of this weakness at our school may have started when we dropped the teaching of inorganic and organic technology. would make mistakes on several of the above items, but the percentage that made these type mistakes and the grade point average (based on quality point averages in engineering courses) of some of the students that made mistakes was alarming. Professors will likely be surprised to learn their students will not do any better if they give this or a similar examination. It is believed other professors will have just as big a disappoint- ment in the results as those of us that cooperated on this test, especially if they will not drill them on these specific type problems prior to giving the test. My analysis of the results reveals a very seri- ous weakness on our part as professors in teach- ing our students to think. It has uncovered a weak- ness in our teaching procedures or curriculum that I think is in need of correcting, if at all possible. Just where and how to undertake to do this, in the best possible manner, is the so-called "$64 question". Some of this weakness at our school WINTER 1974 may have started when we dropped the teaching of inorganic and organic technology. Any courses where flowsheets of various processes were rather thoroughly discussed emphasizing reasons for the various pieces of equipment, operating conditions, catalyst, etc., served to help the students apply engineering principles. PROCESS FLOWSHEET DISCUSSION TWO OR THREE PROCESS flowsheets involv- ing various types of equipment are discussed in my plant design course. Then the students are required to lay out a process flowsheet. Appar- ently, they are able to find their particular process flowsheets illustrated fairly completely in the lit- erature, but they do not receive enough practice in thinking out the reasons why all the specific equipment is used. There are many items that the students should have thoroughly fixed in their minds before they undertake a course in plant design. Some of these items are: * Pumps are used to move liquids and compressors are only used to move gases. * It costs a great deal more to elevate the pressure to some higher pressure by a compressor than it does a like weight of liquid by a pump. * One does not vaporize material and then use a com- pressor to elevate it to some higher compression level if it can be elevated to the higher compression level first by a pump, then heated to the desired conditions to con- vert it to a vapor. * One does not heat something to a higher temperature than the heating medium being used. * Compounds having lower boiling points go out the top of an ordinary fractionator and the higher boiling com- pounds go out the bottom. * All ordinary fractionating towers have a lower tempera- ture and pressure at the top than at the bottom. * All ordinary fractionating columns must have reflux and reboilers. These and many other statements that could be listed should be fixed in the students' minds before starting plant design. I have tried to analyze why this weakness ex- ists with our present day students. Just about all graduates of 20 to 30 years ago were required to take courses in organic and inorganic technology. In those courses taught to me, process flowsheets were discussed thoroughly in class and students were required to give reasons why the type of equipment used was needed; why specific operat- ing conditions were best, based on kinetic and thermodynamic relationships; the likely poisons for catalyst, considering the chemical reactions that were likely to occur, etc. These courses have been dropped as required courses and in many curricula are not even offered. At least, I think those courses taught me to think and learn to apply fundamental chemical engineering princi- ples. This causes me to wonder if we have not made a mistake in eliminating these courses. The other possibility is to utilize flowsheets in teaching some of the fundamental chemical engineering principles in such courses as mass and energy balances, unit operations, mass transfer phenom- ena, thermodynamics, kinetics, and plant design. NOT ENOUGH PRACTICAL APPLICATION IT HAS BEEN OBSERVED that the students are keen at memorizing fundamental principles, laws, rules, and derivations of equations, but when asked questions where these are to be used or could be applied to think out an answer or a solu- tion, the students seem to fail to recognize the source of help. There appears to be too much em- phasis placed on derivations of equations, theo- rems, etc., and not enough practical application. Perhaps the lack of industrial experience of fac- ulty members or the tendency of faculty members to teach undergraduates like they were taught graduate courses, where derivations of equations were stressed, may have something to do with the weakness of students in the application of engi- neering principles. At any rate, this test has convinced me that our ChE curricula have one serious weakness in the fact that so many of our graduates cannot do a better job of applying chemical engineering principles. O E. C. Oden is a graduate of the University of Alabama and Brook- lyn Polytechnic (M.S. '38) and has done graduate work at Cornell and the University of Michigan. He has many years experience in the chemical and petroleum industries and is presently teaching plant de- sign. CHEMICAL ENGINEERING EDUCATION |f i |'~, , t L '"""P I .I 0 ', ' , - L l, * t I - I I WI S - - w - - -t ' 1^- -� I -� S �* �� * I - jJ - * * - . < - I. t r j I I.I i,' - i i' - .~ Ir.: . ^ ii ' '* .. * > a mifr* 4 '\p 384 i. I - i '- iffff L- if . .. . i ; - * -' - s , . -. ...-. '- i. i 3' ' P - 'i,', ii if - - . - _. - ac. .L ,' c ""*-.*y - y;'-~- .. ...... .. 4" )7L * i ' ". i -i (jiC��4' i,- Ce' dl, ' if ' - if-i.. .'. t if . p - , if . j T-c S' * ' o . ,* /* f f < jf / i 4i I'. 1 :s " '. I: f* 21 * *V'if.^ l ^ ^ "^a 1� .... -. i1 1 - S. ... . . . . . .. C^lucitet 7T ^- *- f Si i f-, __ 7} -a 1 --..- ... r t f ! t :K:--- .-Il *ifi I, Is fb.l ^K I 'i f i ' _ . i ' -- , j ... . t 4 . If i. . -.--- -, - ; . � 7;Lif: f; : . A;' J" , j. 2�iff a if C ' jf 8? i r / - ^i i A if" 12. 1d i i if . tr *<' - fifu i i - (*r ,* t. i t' * r :v * jifj*^ . -*- - , if.. *� * if i . ( . f-- - ?.; f ' : ; - - -.^, ^ , . L. . i ..-.-. . .: ^. ^ .. FI L' .. 4 - t -' -- ^�A _ ~' ** " t f . ' " - _.-^ ' ----- 7 -]- ^4.iift i i f_ . _ . _M~T -.'L. if.. 't if'ifL, : i , . . \ . . . . - - {rfsr.I J ,I f if-" - 1 . w ; L if^ " _ . i.. Z 4 " i i- i � 1 ^/ I.' I5-i � - It', -I�--L - .4. i , 4if r 4 " - ... 7 i !. 'ifI .itfi 1/C--i 4t.4- K--- 4.,' 1. -$It i a if,; .4 S* I . I *I * t d I, t- t--t- --~:. ..t , 1973 4Awcad Leckti4e THE THEORY OF DIFFUSION AND REACTION A Chemical Engineering Symphony RUTHERFORD ARIS University of Minnesota Minneapolis, Mn. 55455 ALTHOUGH CHEMICAL ENGINEERS have been far from alone in their work towards a comprehensive theory of diffusion and reaction, their contributions have been so substantial and significant that it is only stretching the truth a little to claim the subject for our discipline. To claim that it is a symphony, an articulated and developed structure shot through with certain themes, held together by the relationships of its movements and breathing an inner life of its own -that is a claim of another sort. Yet, at the risk of being regarded as a shade fanciful or a mite precious, I will persist in offering the analogy for if, as Galileo held, "The book of nature is written in the language of mathematics" and if, in mathe- matics, structure is of the essence then we must always be concerned for structure. Indeed some have gone so far as to claim that a knowledge of structure is the "only articulate or communicable knowledge that we can attain". Be that as it may, the emphasis on structure needs no justification to a society devoted to engineering education. But structures are not enjoyed entirely in isolation and it is tempting to employ that bright gift of our mediaeval brethren, the art of analogical think- ing, to enliven this enjoyment. Nor am I alone in this predilection for I have heard one of the great men of our profession, R. B. Bird, subtitle his seminar "A sonata on rheology and kinetic theory". Like all analogies, its tempo and timbre must be carefully controlled, but with this under- stood the orchestra can be allowed its head at least until we land in the ditch with a fine flourish of mixed metaphors. I would like to begin by delineating the main outlines of the subject as I see it and to go on to some comments on its history which may serve to clothe the bare bones of abstraction with a few sinews and a little flesh. THE STRUCTURE OF THE SUBJECT The theory of diffusion and reaction in perme- able catalysts may be divided into four move- ments. The first, an allegro in sonata form, states and develops the partial differential equations from which all must depend. It is followed by a slow movement in sonata-rondo form, definitely andante for it deals with the steady-state solution of these equations and equally pedestrian, though important, matters. The tempo picks up a little (allegretto) in the third movement, a minuet and trio concerned with the question of uniqueness and its bearing on stability. This theme carries over to the fourth movement, a set of variations on the question of stability and transient behavior-presto vivace. The distinction between the first half of the subject and the second is a clear one and the dif- ficulties they present are those encountered by the great lexicographer. For if the results on steady state are, as Dr. Johnson said of the English tongue, "Copious without order", the newer de- velopments on uniqueness and stability are cer- tainly energetick without rules". Indeed it will be some years before a comprehensive account of these developments can be given. CHEMICAL ENGINEERING EDUCATION . . if Galileo held, "The book of nature is written in the language of mathematics" and if, in mathematics structure is of the essence, then we must always be concerned for structure. The theory of diffusion and reaction in permeable catalysts may be divided into four movements-allegro, andante, allegretto, and presto vivace. "I r t 7 - ',co - z ~-~~ p~.l~� I1k _ 1 1o., "SPL. I JV I , xtlo' e. v PI-1, 0 , o- , I Tnii8 oio t THE TWO SUBJECTS OF the first movement may be introduced without delay for they are the partial differential equations governing the concentrations and temperature in the catalytic region f and the appropriate boundary conditions to be applied on Dl. To take a case of fundamental importance for the exposition, an irreversible re- action whose rate R (u,v) depends on the concen- tration, u, of a single reactant and on the temper- ature, v, will give rise to the equations -= 2u - 2R(u,v) (1) 1 = V2v + B22R(u,v) (2) aT where T is the time (made dimensionless by the characteristic diffusion time), V- the Laplacian operator in the dimensionless space variables of the particle, P, the Prater temperature rise, _ , the Lewis number and 4 the Thiele modulus or ratio of the diffusion time to the reaction time. The concentration and temperature have been made dimensionless by dividing them by the con- centration and temperature far from Dn. Hence the boundary conditions are 1 al 1 3v S- u = 1and -+ v = 1 (3) v an 1 In "� ) WINTER 1974 /L and v being the Biot numbers for heat and mass transfer to aD. The basic equations are thus seen to be a pair of parabolic, quasi-linear partial dif- ferential equations with Robin boundary condi- tions. The exposition continues by showing the de- tails of the reduction of the equations to this form and with the generalizations and specializations. The generalizations would include the forms of the equations when there are more chemical compon- ents, more than one reaction or for the case of volume change. The specializations include the isothermal case (for which v is fixed) and the Dirichlet problem (for which 1/ and v tend to in- finity). The exposition of these two subjects con- cludes with the definition of the characteristic functional of the solution, the effectiveness factor, = I R(u,v)dV (4) In the development section the physico-chem- ical basis of the equations may be examined. They rest of course on the principles of the con- servation of mass and energy, but the constitutive relationships that go into these are based on the laws of diffusion and of reaction and on certain models and idealizations of the actual structures. Thus the concept of an effective diffusivity in a porous medium needs to be developed on the basis of the best available understanding of the struc- ture of these materials. In the recapitulation the justification for using a homogeneous model must be discussed. The catalytic reaction actually occurs at discrete sites on the walls of a network of pores and it is there that the transformation of matter and exchange of energy take place. The degree to which these are minuscule events happening very close to- gether and uniformly dispersed throughout the particle is the degree to which an homogeneous set of equations will be justified. The case of a zeo- litic catalyst, where a small proportion of sieves is sparsely distributed through an inert medium, calls the homogeneous model in question. Here also the circumstances in which the equations can he reduced to a single equation and the forms taken by the resulting nonlinearity may be con- sidered. The final transmogrification of the steady-state theme is to the question of multiple reactions. For first order reaction systems there are immediate analogies with the simplest theme of a single first-order reaction. IF 1C _xlutrL oK4 t ciqatto5 J.- ct f -(auy '. - -S<,, : , Lt~v uL. , ,,,,r,- subject, the steady-state solution, appears in four forms of increasing development and com- plexity. The basic features are found in its first exposition in the context of a first-order, iso- thermal reaction (A1). Here the distinction be- tween the Dirichlet and Robin problems, the ef- fects of particle shape and the asymptotic be- havior can be readily appreciated and these are themes that recur. After a section (B') on varia- tional methods, whose validity though rooted in the linear situation yet reaches out to monotone non-linearities, we come to isothermal kinetics not of the first order (A'). This embraces the p"' order reaction, Langmuir-Hinshelwood kinetics and such added features as surface diffusion and electrostatic effects. The possibility of unsym- metrical solutions, which arises as soon as there is more than one stable solution, and the utility of singular perturbation analysis provide a bridging section to A:, the discussion of the non-isothermal case. Here the question of uniqueness really comes to the fore and the problem of computing the ef- fectiveness factor is an important one. It is there- fore appropriate to consider the approximations and applicable numerical methods (B2). These have a certain affinity with variational methods though this connection is not to be over-empha- sised. The final transmogrification of the steady-state theme is to the question of multiple reactions. For first order reaction systems there are immediate analogies with the simplest theme of a single first- order reaction. For in the one case we have D u - ku (5) dr2 with u u, at r = a and this leads to the solu- tion u (r) = ucoshd (r 'a) /cosh4 and the effective- ness factor 77 = (tanh ), where 2 = a'k D. In the case of multiple reactions we have 2 d2u D K u (6) dr2 where D and K are matrices and u a vector of con- centrations that is specified as u = u, at r = � a. Let (1) be the matrix defined by ( = a-'D K and an effectiveness matrix H be defined by setting HKu. equal to the actual rate of reaction in the presence of diffusion. Then it can be shown that D-1H K = ()tanh(l (7) in close analogy to (b21 reactant. (tanh(f for the single R .tsno ticcutt p u tidclu4Ce f I. .t. Ev\p''e 0 LC't . rcs 1i0rnr on f rk e i' t ....ie. i'u''es iif ito;'u v n.r t rtCA. ' T HE THIRD MOVEMENT takes us into the question of uniqueness and the preliminary considerations of stability. The general feature of problems in diffusion and reaction is that for suf- ficiently small and sufficiently large systems the solution is unique. It is only for systems of inter- mediate size that multiple solutions can exist and then only if the kinetics are sufficiently nonlinear. Thus we can discern three groups of parameters: the kinetic group, such as the Prater temperature CHEMICAL ENGINEERING EDUCATION p/, the Arrhenius number y and the order of reac- tion, p, as in the expression for a p"'-order irre- versible reaction R (u,v) = uPexpy (v-l) /v; (8) the transfer group, namely the Biot numbers, It and v, and the parameters of the internal dif- fusion; finally there is the Thiele modulus which measures the size of the system in terms of the relative characteristic rates of reaction and dif- fusion and thus links the chemical and physical features of the problem. We can thus ask for suf- ficient conditions on the parameters of one class which will ensure uniqueness when the parameters of another class lie in a given range. For example if p and v are infinite (Dirichlet problem) we can ask for conditions on p, p, y such that the solution is unique for all values of b. Luss has shown that the monotonicity of R (1-w, 1+pw) /w is sufficient for this. Jackson has extended this to the Robin problem by showing that the monotonicity of R(1-w-w, l+3w+a/3w) /w (a = v/I) with re- spect to both w and w is a sufficient condition. Such conditions as these are "safe" but how prox- imate they may be to the exact condition has to be determined computationally; for example, Luss' condition for a first order reaction in a slab is ex- traordinarily close to the exact results. Since uniqueness is to be expected for suffi- ciently large and sufficiently small values of the Thiele modulus (say, 4 > "4), < it),it is also of interest to try and obtain estimates of these so- called bifurcation values. In particular we would like a lower bound for I,, and an upper for 4)" so that the region of multiplicity would be effectively delimited. Luss has obtained the former but the results on the latter are still only partial. In the third movement it is appropriate also to raise the quasistatic questions of stability. Thus, it is often possible to give sufficient conditions for instability from an examination of the steady- state equations or to use Liapounov methods of the second kind which though involving the tran- sient equations do not require anything approach- ing a solution of them. Jackson has given a very elegant geometrical interpretation to the analysis of stability which shows that for the Dirichlet problem only the maximal and minimal solutions can be stable. Specifically, he divides the -q,o curve up into segments at the points where dd/d4 be- comes infinite. A segment such that (d '/d4) -+ - sx at either or both of its ends must corre- spond to unstable steady states. (. Un iitt . co a vaost' t' LI,,, i cY J "' .".t"1 ,,,Ls + C.i4 , I' l t'u 1 -1 L;. rpnLI-n. Co'(7C-C >I ^X et's' f l^ Dfl50> 'A. THE FOURTH MOVEMENT is a set of varia- tions on the themes of stability and transient behavior. The key phrase is the introduction of the Lewis number whose value has no influence on the steady state as such but is critical in determining its stability. In particular there is evidence from many directions that a sufficiently small value of the Lewis number, the ratio of the material and the thermal diffusivities, will often render the steady-state unstable even when it is unique. This can give rise to limit cycles in which the concen- tration and temperature at each point oscillate and waves of concentration and temperature wax and receed within the particle. Cyclic operation, as a means of improving selectivity, has been delib- erately cultivated in the work of Horn and Bailey and a recent investigation of Cresswell and El- nashie has shown that the influence of adsorption capacity may have to be considered. Because the exact treatment of the parabolic equations is difficult various methods of approxi- mation have been considered. These consist in some process of lumping or replacing the para- bolic equations by sets of ordinary differential equations. This can be quite a crude analogy with the stirred tank obtained from the first term of a modal analysis or collocation method or a more precise development in a series of equations cap- able of giving as accurate a result as may be wished. Even the simplest of approximations be- trays the same general features but the danger of an approximation of this sort is that its validity is almost unpredictable and at best one can hope to find qualitative and comparative results. The equations governing reaction on the surface of a catalytic wire are already in lumped form and this WINTER 1974 . .a symphony or any work of art may be completed and stands for better or worse, a whole to be praised and performed or disparaged and neglected. But the score of an area of natural philosophy cannot be so ended, but must constantly be revised and rewritten for each performance. allows them to be discussed rather fully. In par- ticular it is found that even when conditions around the wire are independent of position there can be periodic solutions to the equation. How- ever only the uniform state is stable. It is quite otherwise in the case of other solu- tions of the diffusion and reaction equations which lack the symmetry of the problem. The class of solutions discovered by Pismen, Kharkats, Marek, Jackson, Horn and others contains unsymmetrical members whose stability has been established with great care by Aronson and Peletier. Jackson and Patel have shown that the full diagram for the effectiveness factor as a function of Thiele mod- ulus should contains branches corresponding to unsymmetrical solutions. Not only can unsym- metrical solutions be stable, but the symmetrical or uniform state may actually be unstable. Such is the case in certain models of morphogenesis that have developed from Turing's work and in a model of chemotaxis considered by Keller and Segel. In the work of Nicolis and his colleagues it further appears that certain regions of a non-uniform steady state may become unstable and limit cycle behavior may be confined. The sophisticated use of group theory by Scriven and Gmitro to find solu- tions of varying degrees of symmetry has yet to be published, but this is another variation that adds colour and life to the finale. Here the analogy certainly breaks down. For a symphony or any work of art may be completed and stands for better or worse, a whole, to be praised and performed or disparaged and ne- glected. But the score of an area of natural philos- ophy cannot be so ended, but must constantly be revised and rewritten for each performance. At least they have in common that, whether it bring relief or rapture, all such performances must be brought to a close. P1a4094m Notae REFLECTIONS ON HISTORY AND DEVELOPMENT PROPHETIC AS WAS Mikhailo Vasilyevich Lomonosov's remark in 1745-"I saw not only from other authors, but am convinced by my own art, that chemical experiments combined with physical show peculiar effects" [1]-it is straining its context a little to apply it specifically to the question of diffusion and reaction. Yet it has in- terest as a dictum of the father of physical chem- istry and an indication of the opinions far ahead of his time. After his boisterous student days in Marburg (1736-39 reading physics under Chris- tian Wolf) and Freiburg (1739-40 reading metal- lurgy under Henckel), Lomonosov arrived back in St. Petersburg on July 8, 1741, just three days after Euler left for Berlin. He had had a hectic journey what with raising the money for it and escaping temporary impressment in the Prussian hussars and his early years at the Academy of Sciences were so disturbed by his own turbulence and that of his times that he does not seem to have had time to write to the wife whom he had left behind in Marburg. Indeed he had barely made his peace with his colleagues in 1744 when, having made contact with him on her own initiative, she finally joined him in St. Petersburg. The chair of chemistry at the Russian Academy of Sciences had never adequately been filled for the first incumbent had injured himself fatally by tumbling out of his carriage in a drunken state when returning from a symposium only five months after he had arrived and for the next seventeen years it was held by a botanist who spent ten of them exploring Siberia. Lomonosov petitioned Elizabeth to be made pro- fessor of chemistry and, after he had written a satisfactory dissertation on metallurgy, an ukase on his promotion was published on July 25, 1745. With his promotion the petition for the building of a chemical laboratory, which he had been re- newing year by year since 1742, was finally granted and it is from this proposal that Frank- Kamenetskii takes the quotation. CHEMICAL ENGINEERING EDUCATION � L But it was his insistence on the combination of physical and chemical methods that gives him the claim to be one of the founders of physical chem- istry. In his "Elementa Chymiae Mathematicae" (begun in 1741 but never completed) he conceives chemistry as a science of clearly defined chemical elements unified by mathematical methods and in- corporated in a physical system based upon an atomic theory. Ten years later in a "Speech on the Uses of Chemistry" [2,3] he speaks of the relation- ships between mathematics, physics, and chem- istry "Eyes are useless to the man who wishes to see the interior of an object yet lacks a hand to open it. Hands are useless to the man who has no eyes to observe the objects once they have been disclosed. Chemistry may correctly be called the hands, and Mathematics the eyes of Physics. But as surely as each demands aid from the other, just as surely, notwithstanding, they often divert human minds into different paths. The Chemist, who sees in every ex- periment different and frequently unexpected phenomena and products and is thereby allured to gain a speedy ad- vantage, laughs at the Mathematician as being involved only in certain vain cogitations about points and lines. The Mathematician, on the other hand, convinced of his proposi- tions by exact proofs and evolving unknown properties of quantities through incontestable and uninterrupted deduc- tions, scorns the Chemist as occupied only with practice and lost in many chaotic experiments; being himself ac- customed to clean paper and shining geometric instru- ments, he abhors the smoke and dust of Chemistry. And thus up to this time these two sisters, closely associated for the common good, have for the most part given birth to sons of such different opinions. This is the reason why the complete study of Chemistry has not yet been com- bined with a profound knowledge of Mathematics." If Lomonosov belongs to the prehistory of the exact analysis of the problem of diffusion and re- action, its early history and subsequent develop- ment are bound up with some of the great names of chemical engineering with those of DamkBhler and Wicke in Germany, of Zeldowitsch and Frank- Kamenetskii in Russian and of Thiele, Weisz and Amundson in this country. Moreover we have some useful historical accounts in the recollections of Thiele [4] and the Murphree Award Address of Weisz [5]. Indeed it was commonly thought that the exact analysis flowered almost simultaneously in Germany, Russia and the U.S.A. in the late 1930's in the work of DamkBhler, Zeldowitsch and Thiele until a paper of Ferencz Jiittner was dis- covered (as I understand it, by R. L. Gorring of Mobil). This 1909 paper appears to have been al- most totally overlooked for more than sixty years and was certainly unknown to the three who in- dependently arrived at some of its results thirty years later. Jiittner (b. Feb. 28, 1878 Dr. phil. 1901, Breslau) was a natural philosopher who published papers on thermodynamics, the theory of matter and relativity besides the three on chem- ical kinetics which we shall take note of. He is listed in Poggendorf as "Lehrer, Gymnas Brieg Schliesen, 1902", and was evidently a member of the "Schlesischen Gesellschaft fur vaterlandische Kultur" for he read one of these papers to its Mathematical Section on the 4th of May, 1909. In his paper on "Reaktionskinetik und Dif- fusion" [6] Jiittner considers a general reaction nA, nA + . . . n'A', + n'.,A' + . . . and ... it was commonly thought that the exact analysis flowered almost simultaneously in Germany, Russia and the U. S. A. in the late 1930's in the work of Damkohler, Zaldowitsch and Thiele until a paper of Ferencz Juttner was discovered. assumes mass action kinetics, setting up the time dependent equations for an arbitrary region and different diffusion coefficients for each species. In the stationary state and one space dimension he recognizes that certain combinations of any two concentrations will be at most linear functions of position and in the symmetric case will be con- stant. The equations can thus be reduced to a single equation of the form 2 de g(x,c) dx where g is a polynomial of degree (n, + n, + . .) or (n', +n', + . . .), whichever is the greater. In the symmetrical case, when g is a function of con- centration alone, Jtittner showed that the equation could be solved by an implicit function given in terms of an integral, while in the case of a re- versible first order reaction he gives the explicit solution in terms of hyperbolic functions. In the general case he refers to the "new and important researches of Painlev6 on algebraic differential equations of the second order" that had appeared in Acta Mathematica in 1902, but he again treats the reversible first order reaction in detail giving the solution under general boundary conditions. For the second order reaction he gives a series solution and remarks that the implicit solution for irreversible nth order dissociation gives elliptic functions for n = 2 and 3. In discussing the tran- sient case Jiittner gives a formal expansion of (Continued on page 36.) WINTER 1974 ENGINEERING ENVIRONMENTAL SYSTEMS ENGINEERING LINVIL G. RICH, Clemson University. McGraw- Hill Series in Water Resources and Environ- mental Engineering. 1973, 405 pages (tent.), $16.50 (tent.) In this quantitative introduction to the subject, Professor Rich uses a systems approach, in which the focus is on the system as a whole and how its components interact. Although water environment is considered in greatest detail, also included are air pollution and its control, solid waste manage- ment and radiological health. The mathematics of systems analysis and computer solutions is used extensively. THERMODYNAMICS, Second Edition JACK P. HOLMAN, Southern Methodist Univers- ity. 1974, 608 pages (tent.), $14.50 (tent.). Solu- tions Manual. Six audio-tutorial cassette tapes with an accompanying student workbook, $50.00 (tent.) All standard thermodynamics topics can be cov- ered from either the classical or statistical view- point or from any desired integration of the two with this book. This revision includes a sixty per cent expansion of classical thermodynamics and applications, and many new examples and prob- lems worked in both fps and SI units have been added. MOMENTUM, HEAT AND MASS TRANSFER, Second Edition C. 0. BENNETT, University of Connecticut, Storrs and J. E. MYERS, University of Cali- fornia, Santa Barbara. 1974, 604 pages (tent.), $16.50 (tent.). Solutions Manual Combining a rigorous approach to fundamentals with an extended treatment of practical problems, this revision treats principles of transport phe- nomena as applied to simple geometries and then extends the discussion to analyze practical areas such as flow in pipes and equipment, filtration, heat exchangers and evaporators, gas absorption, liquid-liquid extraction and distillation. THE INTERPRETATION AND USE OF RATE DATA STUART W. CHURCHILL, University of Penn- sylvania. 1974, 512 pages (tent.), $17.50 (tent.) Here is a completely new treatment of rate proc- esses in which a generalized structure is used, greatly simplifying and reducing the number of concepts needed to study bulk transfer, mo- mentum transfer, heat transfer and chemical re- lations. Emphasis is on the relationship between design and uncertainties in measurement, and these concepts are reinforced with over 300 prob- lems based on raw experimental data from the literature. SOLIDIFICATION PROCESSING MERTON C. FLEMINGS, Massachusetts Insti- tute of Technology. 1974, 580 pages (tent.), $19.50 (tent.) Here is the only significant book in the field in ten years. Building on the foundations of heat flow, mass transport and interface kinetics, the author presents the fundamentals and relates them to practice. Among the processes considered are crystal growing, shape casting, ingot casting, growth of composites and splat cooling. INTRODUCTION TO METALLURGICAL THERMODYNAMICS DAVID R. GASKELL, University of Pennsyl- vania. 1973, 550 pages, $19.50 Treating in depth the thermodynamics of high temperature systems encountered in metallurgy, this book demonstrates the thermodynamic method through an extensive illustration pro- gram, using as examples real systems which have been carefully selected to illustrate the principles involved. The text introduces basic laws and nec- essary thermodynamic functions and makes appli- cations that are numerous and thoughtful. McGraw-Hill Book Company CHEMICAL ENGINEERING EDUCATION MEANS McGRAW-HILL MASS TRANSFER THOMAS K. SHERWOOD, ROBERT L. PIG- FORD, CHARLES R. WILKE, all of the Uni- versity of California at Berkeley. 1974, 512 pages (tent.), $18.50 (tent.) Compared with the 1952 version, Absorption and Extraction, this volume is substantially more so- phisticated, providing a much broader coverage of mass transfer. Emphasis is on the practical aspects and real problems that demand an under- standing of theory. Yet theoretical derivations are minimized by explicit citation of over 1100 con- temporary references. SCIENTIFIC STREAM POLLUTION ANALYSIS NELSON LEONARD NEMEROW, Syracuse University. 1974, 380 pages (tent.), $16.50 (tent.) A careful balance of the hydrological, chemical and mathematical concepts involved in the evalu- ation of stream quality is achieved in this com- prehensive description of the analysis of water pollution. Practice problems are presented to dem- onstrate the difficulties surrounding stream anal- ysis, and computation techniques for deoxygena- tion and reaeration rates are described and ana- lyzed, as are all factors affecting oxygen concen- tration to give and overall oxygen sag curve in a stream. AIR POLLUTION H. C. PERKINS, University of Arizona. 1974, 480 pages (tent.), $16.50 (tent.). Solutions Man- ual To date, this is the only truly engineering-oriented text on the subject that draws on the student's background in analyzing and solving problems in air pollution. The treatment is sufficiently detailed to enable chemical, mechanical and sanitary engi- neering students to solve a variety of problems, and many applications-type problems are included. ENVIRONMENTAL PROTECTION EMIL T. Chanlett, University of North Carolina at Chapel Hill. 1973, 569 pages, $15.50 ENVIRONMENTAL PROTECTION is man-cen- tered. This book describes the rationale for the management and protection of our land, air, water and energy resources, and examines the conse- quences of mismanagement at three levels: 1) effects on health, 2) effects on comfort, conveni- ence, efficiency and esthetics and 3) effects on the balance of ecosystems and of renewable resources. CONSERVATION OF MASS AND ENERGY JOHN C. WHITWELL and RICHARD K. TONER, both of Princeton University. 1973, 512 pages, $14.95. Solutions Manual Unique in chemical engineering literature is this treatment of degrees of freedom for material and energy balances. Either chemical or physical proc- essing elements are handled in a unified manner. The authors have included the first law of thermo- dynamics, unsteady state mass and energy bal- ances and all physical chemistry required. The modular organization of the material offers the instructor a wide choice for his particular syl- labus. EXPERIMENTAL METHODS FOR ENGINEERS, Second Edition JACK P. HOLMAN, Southern Methodist Uni- versity. 1971, 448 pages, $14.50. Solutions Manual A broad treatment of instrumentation and anal- ysis of experimental data is offered in this re- vision, which contains more information on ex- periment planning and the importance of feed- back during experiments, emphasizing the anal- ysis of uncertainties in planning experiments and instrumentation. A variety of numerical examples, problems and methods are included. Prices subject to change without notice. 1221 Avenue of the Americas, New York, N.Y. 10020 WINTER 1974 Nth l laboratory INDIRECT MEASUREMENT OF REACTION RATE R. D. WILLIAMS University of Arizona Tucson, Arizona s This paper describes an experiment which can be used to study the kinetics of chemical reactions which are accompanied by measurable heat ef- fects. An indirect method of data collection takes advantage of the fact that the rate of reaction is proportional to the rate of energy release or ab- sorption. Laboratory experiments in chemical engineer- ing curricula should be carefully selected accord- ing to the laboratory objective. Experiments which demonstrate several points are especially effective in the curriculum squeeze of today. At the University of Arizona the undergradu- ate kinetics laboratory is used to give the student practical experience in the more important points covered theoretically in the lecture course the semester before. The first three experiments of the lab are con- cerned with a demonstration of the differences in behavior of batch, continuous stirred and tubular reactors. The integral method of analysis is used in conjunction with isothermal batch kinetic data in order to determine the kinetics of the saponifi- cation reaction between ethyl acetate and sodium hydroxide. These kinetics are then used to predict behavior of the two continuous reactor types and these predictions are experimentally checked. The wet chemical method of data collection in these three experiments is tedious and by the end of the third the student is convinced that all kinetic de- terminations must be equally frustrating. The fourth experiment was chosen in part for its comparative experimental simplicity. But more than this several important points from the theory course are well illustrated. These are enumerated below. * An indirect data collection method is illustrated. * An energy balance is required in addition to the material balance. * The data cannot be conveniently analyzed by the integral method whereas the differential method can be used. * Not only the kinetics, but also the stoichiometry and heat of reaction may be very simply determined. Dick Williams received his undergraduate degree at Texas Tech University and his graduate degrees at Princeton University, all in Chemical Engineering. He has been at the University of Arizona since 1968 where his research has been involved primarily with chemical reaction engineering. Current research projects include design of a system to reduce automobile pollutants while increasing fuel economy and a study of hydrometallurgical leach recovery of minerals from their ores with emphasis on characterization of the underlying mecha- nisms involved. This fourth experiment involves the deter- mination, in an adiabatic-batch reactor, of the kinetics of the exothermic reaction between hy- drogen peroxide and sodium thiosulfate. Glasser and Williams' have demonstrated a slightly more general technique using the acetic anhydride hy- drolysis reaction. The former reaction has the pedagogical advantage of a non-obvious stoichio- metry which can be experimentally determined. Several possible reactions between hydrogen per- oxide and sodium thiosulfate are listed in Table 1. CHEMICAL ENGINEERING EDUCATION Root and Schmitz' utilized this reaction in dem- onstrating reactor instability in an adiabatic loop reactor. Their analysis did not require a detailed knowledge of the kinetics. Cohen and Spencer: have calorimetrically studied this system to obtain the kinetic details. An indirect method of data collection takes advantage of the fact that the rate of reaction is proportional to the rate of energy release or absorption. that the maximum occurs near a reactant ratio of two implying that the major reaction occurring is VI in Table 1. A check on this result can be made by calculating the theoretical heat of reaction and comparing this value with values obtained from the experimental data using Equation 1. These re- sults are given in Table 2. HRH pC 'T RA 0 FIuURE I: [/PICAL TEMPERATURE - TIME TRACE. EXPERIMENTAL The experimental apparatus consists of a 500 ml beaker, a magnetic stirrer, and a thermo- couple-strip chart recorder arrangement. Volumes of two molar solutions of each of the reactants are mixed in the beaker and the temperature is re- corded as the reaction progresses. An s-shaped curve such as shown in Figure 1 is obtained. If the total reaction mixture volume is held constant while varying the relative amounts of each re- actant, then the temperature rise will go through a maximum when the reactants are mixed in their stoichiometric ratio. A graph of AT versus initial concentration ratio will exhibit this behavior. A typical result is shown in Figure 2. It can be seen TABLE 2: Comparison of Student and Literature Vlues kcaI/ole Na S23 kcal /moe iters/iole-see student i terature Sef. 3 7.33 X 1011 6.35 X 10 THEORETICAL The kinetic data can be analyzed in light of the theoretical temperature-time relationship. The material and energy balances for an adiabatic, constant volume batch reactor are given below. dal dt A SdT pC - (-H ) R p dt R (3) (3) These are subject to the initial conditions, a(O) = ao; T(O) = To. Equation 2 can be divided by Equation 3 in order to eliminate the nonlinear rate term. Inte- gration of this result gives a relationship between reactant concentration and temperature. WINTER 1974 A 11 KJ , 7C a=a (T-T) S HR A Assuming the reaction to be irreversible and first order with respect to each reactant the ki- netic rate expression becomes, R=kab .. the exothermic reaction between hydrogen peroxide and sodium thiosulfate has the pedagogical advantage of a non-obvious stoichiometry which can be experimentally determined. where B b = b + B ( a - a ) A or when reactants are initially present in the stoichiometric ratio, b B b =--a. ). Assuming Arrhenius temperature dependence for k, Equations 4, 5 and 7 can be inserted into Equa- tion 3 to give a single nonlinear ordinary differ- ential equation giving the temperature-time de- pendence, dT (T 2 dt Y (Tf - T) e-E/R T e g 3 , I I I I , I 1 3.0 3,1 3,2 3,3 ",4 This suggests that a plot of log (dT/dt 2) versus (Tf- T) 1/T should give a straight line of slope -E/R, if the assumptions made with regard to the rate ex- pression are correct. The pre-exponential factor can then be calculated from Equation 8. The temperature derivative is easy to determine in this experiment since a continuous temperature- time trace is obtained. Typical student results are plotted in Figure 3. As was the case in Figure 2 these data are from experiments run by several different groups on different days. Values of E and k,, from Figure 3 are given in Table 2. D REFERENCES 1. Glasser, David and Williams, Don F., "The Study of Liquid-Phase Kinetics Using Temperature as a Meas- ured Variable," I&E.C. Fund., 10, 516 (1971). 2. Root, R. B. and Schmitz, R. A. "An Experimental Study of Steady State Multiplicity in a Loop Reactor", AIChE J., 15, 670 (1969). :3. Cohen, W. C. and Spencer, J. L., "Determination of Chemical Kinetics by Calorimetry," Chei. Engr. Prog., 58, 40 (1962). a,b C, E AH, k lko R R, t T AT v P NOMENCLATURE reactant concentrations, moles/liter solution mean heat capacity, calories/gm-�K activation energy, kcal/mole heat of reaction for a given stoichiometry, kcal/ mole reaction rate constant, liter/mole-sec pre-exponential factor, liter/mole-sec reaction rate for a given stoichiometry, mole/liter- sec gas constant, calories/ mole- K time, sec temperature, �K temperature rise, �K Greek Letters a constant stoichiometric coefficient solution density, gm/liter Subscripts A,B denote different reactant species O denotes an initial condition f denotes a final value CHEMICAL ENGINEERING EDUCATION FIGURE j: ACTIATIJN ENER' o 0 !T/ : T- T2 Basic Principles and Calculations in Chemical Engineering 3rd Edition, 1974 David M. Himmelblau University of Texas, Austin NEW-the Third Edition of Basic Princi- ples and Calculations in Chemical En- gineering gives your students an aid to solving a variety of practical problems in- volving material and energy balances. More than that, it guides your students into forming generalized patterns of attack in problem-solving which can be success- fully used in connection with unfamiliar types of problems. The chapters have been organized into a review of fundamental terms, an explana- tion of how to make material and energy balances, and a review of certain aspects of applied physical chemistry. An Informa- tion Flow Chart appears in each chapter and shows how the topics discussed relate to the objective of being able to success- fully solve problems involving material and energy balances. In Basic Principles and Calculations in Chemical Engineering, Professor Himmel- blau strives to acquaint your students with a sufficient number of fundamental concepts so that they can continue their training in chemical engineering, and start finding solutions to new types of problems of their own. See why over 40 departments of Chemical Engineering adopted this book: D Organization leads the student from easy to more difficult material. E Includes an abundance of examples to represent every principle discussed. D Provides a widevarietyof problemsthat can be assigned without repitition. D Emphasizes some of the more meaningful problems in chemical engi- neering today. 0 Provides answers to nearly 25% of the problems. Teaching and Learning aids: D Completely worked-out example problems illustrate the principles involved. D A large number of illustrations are pro- vided to amplify the text. D Graphs and tables furnish sources of data for the example and homework prob- lems. D ASolutionsManual isavailable which contains detailed solutions to all of the homework problems together with typical examinations and course outlines. January 1974, 544 pp., cloth $15.95 For further information please write: Robert Jordan, Dept. CJ-740, College Division, rMeW classroom 4IM 2ndeur&a%9*da Cowue INTERFACIAL PHENOMENA FOR ENGINEERS A Bridge Between Engineering and Life Sciences DINESH O. SHAH University of Florida Gainesville, Florida D DURING RECENT YEARS it has become in- creasingly evident that the principles and techniques of chemistry and physics of surfaces are of considerable importance in chemical engi- neering. Theoretical and experimental research in this area have appeared in the chemical engineer- ing journals under the general title of "Interfacial Phenomena." Therefore, it is not surprising that many chemical engineering departments have in- cluded in their curriculum courses on interfacial phenomena or surface and colloid chemistry. In the winter of 1972 I was asked to present three lectures on the principles and techniques of sur- face chemistry to undergraduate students in chem- ical engineering as a part of the course on "Ma- terials of Chemical Engineering." I presented an introduction to surface tension, interfacial ten- sion, miscibility of liquids, foams, emulsions and wettability of surfaces. Surprisingly, about 15 undergraduate chemical engineering students sub- mitted a petition to the department requesting that an undergraduate course on interfacial phe- nomena be offered. At the suggestion of the de- partment, I formulated a course to be given be- ginning the spring quarter of 1972. My main objective in teaching this course was not to make every student an expert in surface and colloid science. Rather, the course would offer them a better understanding and apprecia- tion of the principles and applications of surface- active molecules, the properties of surfactant solu- tions at various interfaces, and also a number of applications such as foams, emulsions, lubrication and flotation of minerals. Among the textbooks available, I suggested Physical Chemistry of Sur- faces by A. W. Adamson. Interfacial Phenomena by J. T. Davis and E. K. Rideal was suggested as a reference book. However, it is important to men- tion that these books were not appreciated by most of the students. The fact that most of the material presented to the class was derived from a number of research papers, review articles, and other specialized books, contributed to their poor ap- preciation of these books. The course was de- signed for 3 credit hours and was taught three lectures per week. Instead of giving numerical examples as homework problems, I decided to pro- vide them a number of reprints related to the topics being discussed in the class as required reading material. TOPIC OUTLINE The following is a brief outline of the topics followed during the quarter. 1. Introduction: surface-active molecules and five major interfaces; i.e., gas liquid, liquid/liq- uid solid liquid, solid/solid, solid/gas. 2. Properties of surfactant solutions: surface tension, CMC, Gibb's adsorption isotherms, sur- face excess concentration, solubilization, pH near a charged surface (i.e., surface pH vs. bulk pH), effect of salts, chain length, temperature and ad- ditives on CMC; cylindrical and lamellar liquid- crystalline structures of surfactants. 3. Spreading of a liquid on another liquid: spreading coefficient, effect of surfactants on spreading of oils, interfacial instability and inter- facial tension, surface pressure, Marangoni effect. 4. Spreading of liquids on solids: work of co- hesion and adhesion, contact angle and wettabil- ity, critical surface tension of solids. 5. Insoluble Monolayers: surface pressure-area curves, cross-sectional area of molecules, effect of temperature on phase-transitions in monolayers, CHEMICAL ENGINEERING EDUCATION Dr. Shah received his undergraduate training at the University of Bombay and his doctoral degree in biophysics from Columbia Univers- ity in 1965. He spent a year at NASA Ames Research Laboratory in California working on chemical evolution and the origin of life, and surface chemical aspects of the origin of membranes. Later he moved to the Biological Oceanography Division of Columbia University and worked on dispersion of oil spills, retardation of evaporation and wave damping by thin films of surface active agents and on surface chem- ical aspects of sea water. Since 1970, he has been at the University of Florida with a joint appointment in Anesthesiology, Biophysics and Chemical Engineering Departments. Dr. Shah has published in the areas of biological and model membranes, chemical evolution and the origin of membranes, foams, microemulsions, boundary lubrication and sur- face chemical aspects of vision, and anesthesia. He received the "Ex- cellence in Teaching Award" of the University of Florida for 1972-73. reactions in monolayers, surface potential, sur- face radioactivity, surface absorption spectra measurements, surface viscosity and two-dimen- sional Newtonian and Non-Newtonian liquids, equation of state for monolayers, electrical double layer and Gouy potential, effect of pH and salts on monolayers, surface pk vs. bulk pk for mono- layers, mixed monolayers and molecular associa- tions in 1:1, 1:2 and 1:3 molecular ratios. Mono- layers of biological lipids and the correlations with membrane phenomena. 6. Foams: stability of soap bubbles, rate of drainage, surface viscosity and molecular pack- ing, foam stabilizing and antifoaming agents, foam fractionation and other applications. 7. Macro- and Microemulsions: oil-water-sur- factant systems, effect of structure, concentration and chain length of surfactant on emulsion prop- erties, HLB values, spontaneous emulsification, phase-inversion, emulsion rheology and stability, various applications of emulsions. 8. Flotation of Minerals: collectors, brothers, activators, and depressors, selective flotation, ab- sorption of collectors on minerals, contact angle and flotability, use of oppositely charged collec- tors, ion-flotation. 9. Friction and Lubrication: Boundary and hydrodynamic lubrication, coefficient of friction, scuff load, percent metallic contact, wear rate, biolubrication, synovial fluid, structure of lubri- cant additives. 10. Gas/Solid Interface: Physical and chemical adsorption, catalysis, various types of adsorption isotherms, monolayer-multilayer adsorption and capillary condensation, pore volume, hysteresis. 11. Artificial Organs: Nonthrombogenic sur- faces, blood-clotting, Heparin, biomaterials, trans- plants and implants, biological and model mem- branes, surface chemical aspects of lungs and cornea. EXPLANATION BY DEMONSTRATION On several occasions, I gave experimental dem- onstrations to make concepts clear and interest- ing. For example, two dimensional liquid and solid monolayers of stearic acid, respectively, on subsolutions of NaC1 and CaCL. were distin- guished by sprinkling talc particles and blowing air toward the particles. For monolayers in the liquid state, the particles move freely in the sur- face, whereas for solid monolayers, the particles do not move at all. In another experiment on the use of a wetting agent for wettability of surfaces, I dipped a polished teflon bar into aqueous KMnO, solution, and pulled it out. The teflon rod re- mained white because water did not wet the teflon. However, upon adding a few drops of soaps or detergents, when the same process was re- peated the teflon became pink when removed from the KMnO, solution, suggesting that soap mole- cules caused water to wet the teflon surface. Many such demonstrations on foams and emulsions made students appreciate the importance of sur- face chemistry in many engineering applications. There were two examinations, one mid-term examination and a comprehensive final examina- tion. Here again, instead of giving numerical ex- The course would offer... a better understanding and appreciation of the principles and applications of surface-active molecules, the properties of surfactant solutions at various interfaces and a number of applications ... WINTER 1974 S.. it was successful in giving a bird's eye view of a number of applications of surface chemistry in chemical engineering . . . and . .. balancing mathematically oriented courses, such as transport phenomena, process control, and kinetics, with a descriptive and application oriented course. amples to solve, I submitted extensive multiple choice questions during both of these examina- tions. Each of the questions tested their thorough understanding of the principle involved rather than any memorization of equations. The ques- tions were phrased in such a way that the possi- bility of guessing the answer was minimized. I should mention that often students took as much as two and one-half hours to answer 20 multiple choice questions. A few of these questions are mentioned as follows: 1. The contact angles of equimolar solutions of hexanoic acid (C-,-COOH) and decanoic acid (C,,-COOH) on a copper plate were found to be respectively and . (0�, 700, 110") 2. An off-shore oil spill decreases the surface tension of air sea interface to 40 dynes/cm. What should be the spreading pressure (-) of a surface- active agent to push the oil spill away from the shore line? 3. The surface viscosity of monolayers of ste- aric acid (CICOOH) cis, oleic acid (Cs-CH=CH -C,-COOH) and elaidic acid (Cs-CH=CH- C,-COOH) trans were measured at a surface pressure 10 dynes/cm. The surface viscosities were found to be respectively , and centipoises. (3.7 x 10-1, 4.1 x 10-4, 9.7 x 10-4) 4. For two sliding surfaces the coefficient of friction was 0.02 and 0.07, respectively, at the load of 1,000 gm and 2,500 gm. Is this hydrody- namic or boundary lubrication? 5. The palmitic acid monolayers were studied at 25'C, 35'C, and 45�C. The average area per molecule at a surface pressure 10 dynes 'cm were found to be respectively, and A2 molecule. (28, 21, 35) The numbers in parenthesis were not correct values, but simply indicated the trend or ordering of values. The first question is based on the effect of chain length on adsorption of surfactant on a solid surface. The second is based on the Marangoni effect; i.e., the surface flow occurs from a high surface pressure region to a low sur- face pressure region. The third question is based on the effect of cis or trans double bonds on the area molecule or molecular packing and hence on the surface viscosity of monolayers. The fourth is based on the definition of hydrodynamic and boundary lubrication from the variation of co- efficient of friction with load. The fifth question illustrates the effect of temperature on the aver- age area per molecule in monolayers. STUDENT AND TEACHER EVALUATION A MONG THE 15 STUDENTS who took this course, 12 made more than 85' points on both comprehensive examinations. This was par- ticularly satisfying because more than 60 ques- tions were asked from the materials presented throughout the course. The students were also asked to prepare a term paper on a topic in the general area of interfacial phenomena to be sub- mitted at the end of the quarter. The process of preparing a detailed term paper exposed the stu- dents to most of the available sources of informa- tion in the area of interfacial phenomena. The quality of the term paper was taken into account in giving the final grade for the course. I would like to add a note regarding the evalu- ation of this course by the students in the class. Again, to my great surprise, this undergraduate course on interfacial phenomena brought me the Excellence in Teaching A'ward sponsored by the Standard Oil of Indiana Foundation. The follow- ing are a few comments made by students in the teacher's evaluation forms about this course. "Find a better textbook. . . It would be hard to make improvement in such an excellent course... I enjoyed it very much. Best course I ever had in chemical engineering. . . Excellent course and teacher; need better textbook... This is the most interesting course I have ever taken. . . One of the most interesting, well taught courses I have ever had. Greatly increased my interest and knowl- edge. . ." CHEMICAL ENGINEERING EDUCATION The course, because of its extreme breadth, could not go into great depth in many of the topics discussed. However, it was successful in giving a bird's eye view of a number of applications of surface chemistry in chemical engineering. This course was successful in balancing a number of mathematically oriented courses, such as trans- port phenomena, process control, and kinetics, with a descriptive and application-oriented course. The course provided a brief introduction of de- tergents, foams, emulsions, lubrications, and other biomedical areas to chemical engineering students. I also repeated this course in the spring of 1973 with very similar responses by the students who took it. However, this time I used Surface Chem- istry by L. I. Osipow (R. E. Krieger Publishing Company, Huntington, New York) as a textbook, which was better received by the students than the previous two books. I believe a course on interfacial phenomena would be a very desirable part of the undergradu- ate chemical engineering curriculum, and would contribute greatly in exposing the students to the real systems which chemical engineers are more likely to encounter in their professional careers. D Ilew &CC O eate... CACHE COMPUTER PROBLEMS CHEMICAL ENGINEERING EDUCATION, in cooperation with the CACHE (Computer Aides to Chemical Engineering Education) commit- tee, is initiating the publication of proven com- puter-based homework problems as a regular feature of this journal. Problems should be appropriate for use in an undergraduate or first year graduate chemical engineering course. Problems should be documented according to the published "Standards for CACHE Compu- ter Programs" (September 1971). That docu- ment is available now through the CACHE representative in your department or from the CACHE Computer Problems Editor. Because of space limitations, problems should normally be limited to twelve pages total; either typed double-space pages or actual computer listings. Please submit 5 copies of all contributions to Dr. Art Westerburg, C.C.P. Editor Department of Chemical Engineering University of Florida Gainesville. Fla. 32611 WINTER 1974 - I �I � � I I � r I I THEORY OF DIFFUSION & REACTION (Continued from page 25.) The concept of the effectiveness factor does not emerge from this work. The idea of a meaningful fudge factor is peculiarly characteristic of the engineer's need to wrap up the theory in an effective and practical parameter, the physically significant functional of an underlying function. the solution for first order reversible reaction and comments on a reduction to Fourier's equa- tion when the reaction is irreversible. He con- cludes with a correct formulation of the non-iso- thermal problem in which the diffusion coefficients are functions of temperature, remarking "Man erkennt, wie ausserordentlich gross die Schwierig- keiten fur eine theoretische Behandlung der Gleichung sind". All in all it is a remarkable paper coming in the early summer of the classical period of kinetic studies and formulating, and where pos- sible solving, equations that were not again taken up until nearly thirty years later. It is interesting to note that the concept of the effectiveness factor does not emerge from this early work. The idea of a meaningful fudge factor is peculiarly char- acteristic of the engineer's need to wrap up the theory in an effective and practical parameter, the physically significant functional of an underlying function.* When the biochemists examined the question of diffusional hindrance with immobilized enzymes their approach was not that of using a multiplicative effectiveness factor but of modify- ing the Michaelis constant for the reaction. Jiittner's paper was followed by another in which he enlarged on the topic of Painlev6's tran- scendents [7] and a third on the general integrals of "ordinary chemical kinetics" [8], which need not concern us in the context of diffusion. Painlev6 had been concerned to find out how transcendental functions were generated by differential equations of the form y" = R (y',y,x) where R is rational in y', algebraic in y and ana- *The concept of the effectiveness factor for these equa- tions probably arose first for the problem of convection from a thin fin. Indeed many of the solutions available for this problem (see, e.g. [1001) can be reinterpreted in terms of first order reaction and diffusion. lytic in x [9]. In particular he found five canonical forms, the first two of which, y" 6y- + x, y" = 2y2 + xy + a would be applicable to isothermal diffusion and second or third order reaction in the slab. Jiittner's paper is concerned with the conditions under which the equations for a second order re- action may be reduced to Painlev6's canonical form, and the essence of his result is that the quadratic terms in concentration and position must form a perfect square. This is always the case for the symmetrical solution but, in contrast to most writers since his time, Jiittner was con- cerned to have scope for general boundary condi- tions and hence allowed for the possibility of un- symmetrical solutions. Thiele [4] notes that a German patent of 1899 has an implicit reference to the possibility of dif- fusion limitation in catalysis and that there are two experimental papers reporting the effect of catalyst particle size [10,11]. In one of these Juli- ard acknowledged that this result "s'explique par le fait que chaque grain constitute un system poreux pr6sentant une surface interne incompara- blement plus grande que sa surface apparante" but he was not able to assess this quantitatively. Wicke and Brotz in 1949 [12] were the first to use two sizes of catalyst and to compare their per- formance in the light of the theory that had by then been developed. FOUR DIMENSIONLESS GROUPS AT THE OUTSET OF his great series of papers on the influence of flow, diffusion and heat conduction on the yield of reactors [13,14,15,16,17] Damk6hler recognized the importance of four di- mensionless groups. The second of these is the ratio of the chemical rate to the diffusion rate and, though this is presented in the context of the tubular reactor, it was obvious that this would also be the key parameter in the study of the cata- lyst pellet. Indeed in his comprehensive article for the Eucken-Jacob handbook "Der Chemie-Ingen- ieur", Damkdhler [181 expresses the condition for there to be no diffusion limitation in the form 2 4v.W transport time Z_ <. p reaction time 2D p dc. P J This ratio, in which p and d, are the length and diameter of the pore, D, the diffusion coefficient within it and vjW c, ratio of a mean reaction rate to a mean concentration, is clearly of the same CHEMICAL ENGINEERING EDUCATION form as his parameter II for the tubular reactor and the criterion is a valid one. However Dam- k6hler does not appear to have published the solu- tion to the full problem* which, in all cases except that of first order reaction, would be needed to re- late the means W and cj to observable concentra- tions. Zeldowitsch came to "the theory of reactions on powders and porous substances", as he called his 1939 paper, by way of studies on adsorption and heterogeneous catalysis [19,20,21]. He recog- nized that the porous catalyst would present an intermediate region of internal diffusion limita- tion between the conditions of small reaction rate when transfer processes would be unimportant and the conditions under which mass transfer to the external surface would control. Without actu- ally solving the differential equations he saw that the depth of penetration would be proportional to V\(D/kS), where D = diffusion coefficient, k = rate constant por unit area, S = internal area per unit volume, and hence the actual reaction rate to V (DkS). He observed that an estimate of the activation energy from data in this region would give half the true value and that an n"t order dis- sociation would appear to be of order (n +1)/2. [22] Thiele [23] considered a straight pore of length At the outset of his great series of papers on the influence of flow, diffusion and heat conduction on the yield of reactors . . . Damkohler recognized the importance of four dimensionless groups. 2ZP opening to a concentration c of the reactant at either end. The concentration c (x) at a distance x from the centre would then satisfy D d2c- = kSc" dx- for the nt" order reaction in a slab or D d (x2 d) kScn 2 dx dx x for the sphere. He obtained the solution for first *The solutions are closely related to those given for a chain reaction in slab, cylinder and sphere earlier in Dam- kdhler's article (p. 375). order reaction in slab and sphere, for second order reaction in the slab and went on to consider the effect of volume change with first order reaction. The solutions and hence the mean reaction rates were functions of the parameter ep VkS/D. This parameter is proportional to the square root of Damk6hler's X, and is the ratio of �p to Zel- dowitsch's penetration depth. The name "Thiele modulus" for this parameter has gained currency and the attribution is not unjust since Dam- k6hler's II was defined in the context of the tub- ular reaction and the mention of X,, though prior to Thiele's work, is a passing one. Thiele presented the solution in the form of plots of the effective- ness factor versus this modulus and it is this con- cept of the effectiveness factor, or ratio of the actual reaction rate to the rate that would obtain if diffusion were infinitely rapid, that has proved so useful. By definition the effectiveness factor has the value 1 when the Thiele modulus is zero and its asymptotic properties as the modulus becomes large are of interest. It may be noted that Thiele assumed that the concentration of the reactant at the pore mouth would be known whereas Zel- dowitsch, though not obtaining any solution of the differential equation, recognized that this concen- tration might be governed by external mass trans- fer limitations. DIFFUSION IN POROUS BODIES AT THE SAME TIME as these developments were taking place the whole question of dif- fusion in porous bodies was being opened up by the work of Wicke [24,25] and Wicke and Kallen- bach [26], who developed the notion of an effective diffusion coefficient, recognized that surface dif- fusion could have an important role and did many of the pioneer determinations. Mention should also be made of the work of Wagner of Darmstadt both for its general influence on the work in Germany and for his papers [27,28], the last of which discusses the question of multiplicity of steady states. Damk6hler had also been concerned with the temperature rise within a catalyst par- ticle and showed that this could not exceed (-AH) D,.c. 'vX, where AH is the heat of reaction, D, the effective diffusivity, c, the surface concen- tration of the reactant with stoichiometry coef- ficient v and X, the effective thermal conductivity of the pellet. His demonstration for a sphere, re- peated later by Wheeler [29], was generalized for any shape by Prater [30], who found that the max- WINTER 1974 . "diffusion and chemical transformation" are interdisciplinary considerations. In fact until recently the physiologists' contributions have been almost entirely overlooked by the engineer and vice-versa. imum possible temperature rise for the dehydro- genation of cyclohexane was some 53 C, consid- erably in excess of the highest figure of 3�C among Damkohler's examples. Aside from these references to the internal temperature the non-isothermal equations received little attention until the late 50's, as Wheeler's two reviews [31,29] and the incorporation of the problem in its isothermal form into the pioneer text of Hougen and Watson [32] show. Schilson, working under Amundson's direction, showed how to solve the equations both for single and complex reactions, but the method of iteration that they used did not lend itsel to calculating a large num- ber of particular cases and they did not calculate effectiveness factor curves, though they were the first to report effectiveness factors greater than 1. When their work was published [33] it appeared only a short time before two papers giving effec- tiveness factor curves, but using the positive ex- ponential approximation to the Arrhenius temper- ature dependence [34,35] and a perturbation solu- tion by Tinkler and Pigford [36]. A year later the comprehensive calculations of Weisz and Hicks [37], which used the Arrhenius temperature de- pendence of the rate constant, appeared. The independent and almost simultaneous ef- floresence of interest in a particular aspect of the problem was to occur again in the mid-60's when Bischoff [38], Petersen [39] and Aris [40] all called attention to a normalization of the Thiele modulus made possible by the implicit form of the solution for the slab. Aris [41] had earlier (1957) given a normalization with respect to shape and this al- lowed the solutions for all problems with Dirichlet boundary conditions to be presented as effective- ness factor versus Thiele modulus curves with the same asymptotes at both zero and infinity. The same insensitivity to shape was discovered inde- pendently by Roughton in a physiological context [42] but both were ignorant of the fact that Wheeler had stated a similar result without proof as early as 1951 [31]. In the last decade the subject has broken wide open and a rough count of the number of papers published per year has jumped from an average of 3 in the 50's to 12 in the first half of the 60's to 35, 48, 59, 80, 70, 82, 60, 78 for the years 1965 to 1972. Aside from filling in some of the gaps in the steady- state picture the most stimulating activity has been on the question of the uniqueness of the steady state solution, its stability and the form of the transient solution that may arise. The mono- graph of Gavalas [431 was a pioneering effort in this direction but many other names distinguished in chemical engineering circles-Amundson [44], Denn [45], Hlava6ek and Marek [46], Horn and Bailey [471, Jackson [48,49], Lapidus [50], Levich [51], Luss [52,53], McGreavy [54], Schmitz [55], Varma [56], Villadsen [57], Wei [58], are to be found. Mathematicians, such as Cohen and Keller [59], Aronson and Peletier [60], Fujita [61], Kastenberg [62], Sattinger [63,64] to mention but a handful. Meanwhile results on the steady state solution have continued to accumulate and have been obtained and examined by Bischoff [65], Butt [66], Carberry [67], Chu [68], Finlayson [69], Gunn [70], McGreavy and Cresswell [71], Petersen [72], Ray [73], Rony [74], Satterfield [75], Smith [76], Stewart [77], and Ostergaard [78] and many others. Nothing approaching a comprehensive overview can be attempted here but it is hoped that some sort of picture emerges from the ac- count that I have endeavoured to give elsewhere [79]. But this story has been told from a chemical engineering viewpoint and, as Weisz has pointed out [5], "diffusion and chemical transformation" are interdisciplinary considerations. In fact until recently the physiologists contributions have been almost entirely overlooked by the engineer and vice-versa. Yet as early as 1928 Hill and Roughton were considering the absorbtion of oxygen into tissue [80-82] and Roughton's 1932 paper contains solutions of the diffusion reaction equations more detailed than any the chemical engineers were to derive for many years. PATTERN AND RHYTHM M ORE RECENTLY THE pioneering paper of During [831 on morphogenesis has borne fruit CHEMICAL ENGINEERING EDUCATION in the effort to show how pattern and rhythm may arise from the interaction of diffusion and reac- tion as for example in Scriven's work with Othmer [84,85] or with Gmitro [86]. Nicolis [87] has given an excellent review of the work of the Brussels school on dissipative structures and limit cycles [88]. These indeed show some similarities of be- haviour to the limit cycles found in non-isothermal catalyst particles [89] hut depend for their ex- istence on an autocatalytic step in an isothermal reaction scheme. Allied to this is the current in- terest in the Belousov-Zhabotinskii reaction [90- 93] and other forms of diffusion wave. The simpl- est wavelike solution of the diffusion equation arising in the one-dimensional propagation of an isothermal autocatalytic reaction c �2c D + Kc(1 - c) 3x arose as a problem in genetics [94] and was con- sidered in 1937 by no lesser mathematicians than Petrovsky and Kolmogoroff. The development of this theory has been couched in terms of combus- tion theory [95,96]. Another biological problem that has had a significant input is the stability theory of chemotaxis [97,98,99] in which it is found that a uniform distribution of organisms is unstable and that their aggregation may be ac- counted for as a transient tending toward a stable non-uniform steady-state. This by no means exhausts the contributions and interactions with biological problems, but hopefully it will suffice to make us aware of the need to pay attention to what our colleagues in other branches of natural philosophy are con- cerned with. D REFERENCES 1. Quoted by D. A. Frank-Kamenetskii in Diffusion and heat transfer in chemical kinetics. 2nd ed, revised and enlarged. Plenum Press. New York. 1969. 2. Lomonosov, M. V. Collected Works. Published by the Academy of Sciences St. Petersburg, 1891-1935. 3. Menshutkin, B. N. Russia's Lomonosov. Princeton University Press. Princeton, N. J. 1952. 4. Thiele, E. W. Amer. Scientist. 55, 176 (1967). 5. Weisz, P. B. Science 179, 433 (1973). 6. Jiittner, F. Z. f. phys. Chem. 65, 595 (1909). 7. - . Z. f. Math. u. Phys. 58, 385 (1910). 8. --. Z. f. phys. Chem. 77, 375 (1911). 9. Painleve, P. Acta Mathematica 25, 1 (1902). 10. Juliard, A. Bull. Soc. Chim. Belges. 46, 549 (1938). 11. Larson, A. T. and Tour, R. S. Chem. Met. Eng. 26, 647 (1922). 12. Wicke, E. and Brotz, W. Chem. Ing. Tech. 21, 219 (1949). 13. Damkohler, G. Z. Elektrochem. 42. 846 (1936). 14. - . Ibid. 43, 1 (1937). 15. - . Ibid. 43, 8 (1937). 16. - . Ibid. 44, 240 (1938). 17. -- and Delcker, G. Ibid. 44, 193, 228 (1938). 18. Damkohler, G. in Der Chemieingenieur (Ed. A. Eucken and M. Jacob). Bd. 3 Teil. 1. Leipzig (1937). 19. Zeldowitsch, Y. B. Acta Physicochim. URSS 1, 449 (1934). 20. . Ibid. 1, 1961 (1934). 21. . Ibid. 8, 527 (1938). 22. . Ibid. 10, 583 (1939). 23. Thiele, E. W. Ind. Eng. Chem. 31, 916 (1939). 24. Wicke, E. Kolloid Z. 86, 167, 296 (1939). 25. . Ibid. 93, 129 (1940). 26. -- and Kallenbach, R. Ibid. 97, 135 (1941). 27. Wagner, C. Z. Phys. Chem. A193, 1 (1943). 28. - . Die Chem. Technik. 18, 1, 28 (1945). 29. Wheeler, A. in Catalysis (Ed. P. H. Emmett) 2 Rein- hold Pub. Co. New York. (1955). 30. Prater, C. D. Chem. Engng. Sci. 8, 284 (1958). 31. Wheeler, A. Adv. in Catalysis. 3, 249 (1951). 32. Hougen, O. A. and Watson, K. M. Chemical Process Principles. John Wiley, New York (1947). 33. Amundson, N. R. and Schilson, R. E. Chem. Engng. Sci. 13, 226, 237 (1961). 34. Carberry, J. J. AIChE. J. 7, 350 (1961). 35. Tinkler, J. D. and Metzner, A. B. Ind. Eng. Chem. 53, 663 (1961). 36. -- and Pigford, R. L. Chem. Engng. Sci. 15, 326 (1961). 37. Weisz, P. B. and Hicks, J. S. Chem. Engng. Sci. 17, 265 (1962). 38. Bischoff, K. B. AIChE. J. 11, 351 (1965). 39. Petersen, E. E. Chem. Engng. Sci. 20, 587 (1965). 40. Aris, R. Ind. Eng. Chem. Fundamentals. 4, 227 (1965). 41. - . Chem. Engng. Sci. 6, 262 (1957). 42. Roughton, F. J. W. Progr. Biophys. Mol. Biol. 9, 55 (1959). 43. Gavalas, G. R. Nonlinear differential equations of chemically reacting systems. Springer Verlag. Hei- delberg (1968). 44. Amundson, N. R. and Luss, D. Chem. Engng. Sci. 22, 253 (1967). 45. Denn, M. M. Chem. Eng. J. 4, 105 (1973). 46. Hlava6ek, V. and Marek, M. Coll. Czech. Chem. Comm. 33, 506 47. Horn, F. J. M. and Bailey, T. E. Ber. Bunsengesell- schaft 73, 274 (1969). 48. Jackson, R. Chem. Engng. Sci. 28, 1355 (1973). 49. - , Horn, F. J. M., Martel, E. and Patell, C. Chem. Eng. J. 1, 79 (1970). 50. Lapidus, L. and Berger, A. J. AIChE. J. 14, 558 (1968). 51. Levich, V. G., Kharkats, Y. I. and Pismen, L. M. Doklady Chem. Tech. 170-1, 209 (1966). 52. Luss, D. Chem. Engng. Sci. 23, 1249 (1968). 53. -- and Lee, J. C. M. AIChE. J. 16, 620 (1970). 54. McGreavy, C. and Thornton, J. M. Chem. Eng. J. 1, 296 (1970). 55. Schmitz, R. A. and Winegardner, D. K. AIChE. J., 14, 301 (1968). WINTER 1974 56. Amundson, N. R. and Varma, A. Chem. Engng. Sci. 27. 907 (1972). 57. Villadsen, J. and Michelsen, M. L. Chem. Engng. Sci. 27, 751 (1972). 58. Wei, J. Chem. Engng. Sci. 20, 729 (1965). 59. Cohen, D. S. and Keller, H. B. J. Math. Mech. 16, 1361 (1967). 60. Aronson, D. G. and Peletier, L. Arch. Rat. Mech. Anal. 53, 000 (1974). 61. Fujita, H. Amer. Math. Monthly 76, 132 (1969). 62. Kastenberg, W. E. J. Math. Anal. Applies. 29, 29!) (1970). 63. Sattinger, D. L. Ibid. 24, 241 (1968). 64. - . Indiana U. Math. J. 21, 979 (1972). 65. Bischoff, K. B. Chem. Engng. Sci. 22, 525 (1967). 66. Butt, J. B. Chem. Engng. Sci. 25, 801 (1970). 67. Carberry, J. J. Catalysis Reviews 3, 61 (1969). 68. Chu, C. and Chon, K. J. Cat. 17, 71 (1970). 69. Finlayson, B. A. The method of weighted residuals and variational principles. Academic Press. New York (1970). 70. Gunn, D. J. Chem. Engng. Sci. 22, 1439 (1967). 71. McGreavy, C. and Cresswell, D. L. Ibid. 24, 608 (1969). 72. Petersen, E. E. Ibid. 23, 94 (1968). 73. Ray, W. H. Ibid. 27, 489 (1972). 74. Rony, P. R. Ibid 23, 1021 (1968). 75. Satterfield, C. N. Mass transfer in heterogeneous catalysis. M.I.T. Press. Cambridge, Mass. (1970). 76. Smith, J. M. and Suzuki, M. AIChE. J. 18, 326 (1972). 77. Stewart, W. E. and Villadsen, J., Chem. Engng. Sci. 22, 1483 (1967). 78. (Astergaard, K. Proc. Int. Cong. on Catalysis. Amster- dam (1964). 79. Aris, R. The mathematical theory of diffusion and reaction in permeable catalysts. Clarendon Press. Ox- ford. 1974. 80. Roughton, F. J. W. Proc. Roy. Soc. Bill, 1 (1932). 81. - . Ibid. Bl40, 203 (1952). 82. Hill, A. V. Ibid. B104, 39 (1928). 83. Turning, A. M. Phil. Trans. Roy. Soc. B237, 37 (1952). 84. Scriven, L. E. and Othmer, H. G. Ind. Eng. Chem. Fundamentals. 8, 302 (1969). 85. - . J. Theor. Biol. 32, 507 (1971). 86. Scriven, L. E. and Gmitro, J. I. in Intracellular trans- port. (Ed. K. B. Warren) Academic Press. New York (1966). 87. Nicolis, G. Adv. in Chem. Phys. 19, 209 (1971). 88. - and Herschkowitz-Kaufman, M. J. Chem. Phys. 56, 1890 (1972). 89. Hlava6ek, V. and Marek, M. Proc. IV Eur. Symp. on Chem. Reac. Engng. Brussels Sept. 1968. Pergamon Press. Oxford (1971). 90. Zhabotinskii, A. M. Biofizika 9, 306 (1964). 91. Franck, G. M. Oscillatory processes in biological and chemical systems. (In Russian). Pub. House Nauka. Moscow (1967). 92. Zhabotinskii, A. M., Zaikin, A. N., Korzukhin, M. D. and Kreitser, G. P. Kim. i Kat 12, 584 (1971). 93. Scriven, L. E., DeSimone, J. A. and Beil, D. L. Science 179, 000 (1973). 94. Kolmogovoff, A., Petrovsky, I. and Piscounoff, N. Bull. de l'Univ. d'Etat a Moscou. Al, 6 (1937). 95. Zelenyak, T. I. Diff. Eqns. 2, 98 (1966). 96. - . Ibid. 3, 19 (1967). 97. Segel, L. A. and Keller, E. F. Nature 227, 1363 (1970). 98. - . J. Theor. Biol. 26, 339 (1970). 99. - . J. Theor. Biol. 30, 225, 235 (1971). 100. Kern, D. Q. and Kraus, A. D., Extended Surface heat transfer McGraw Hill, New York 1972. THE PROJECT APPROACH TO CHEMICAL ENGINEERING-WPI PLAN (Continued from page 15.) * Engineering Studies on an Enzymatic Process for Con- verting Cellulose to Sugars. This process was developed by scientists in the U.S. Army Natick Laboratories. How- ever, no engineering studies had been performed to obtain data necessary for design purposes. Two groups of Chem- ical Engineering students (one group of three sophomores and one group of two seniors) worked on the project to obtain some data which would be useful in the design of a process to convert cellulosic wastes to useful food. Students worked closely with the Natick Laboratory scientists under the direct supervision of the WPI Center Director. They performed experimental studies to obtain rate data in a batch process. They also studied the effects of mechanical stirring, particle size of the ground waste and grinding time on the reactivity of the enzymatic re- actions. In addition to performing experimental work, students also were required to have some specific background in mathematics, biology and engineering for successful analy- sis of their data. They obtained some of this background from their course work, but had to learn a major portion of the material on their own in order to satisfy their specific needs. While close supervision was maintained in the Center, the students were provided with the opportunity to try out some new ideas. For example, one group tried to use ultrasonic equipment to treat the suspension of shredded newspaper and to test its reactivity. Both groups performed very well in their work. The sophomore group wrote an excellent report detailing their findings and their interpretation of the experimental re- sults. The work performed by the senior group was re- ported in the student paper session of the ACS meeting in Boston, Mass. * Determination of the Effects of Gymnema Sylvestre on the Taste Receptors in Hamsters. This project, which is entirely different from the usual chemical engineering projects, involved one sophomore. She worked closely with a scientist from the U.S. Army Laboratories. As this is a highly specialized field outside that of chemical engineer- ing, a major portion of the supervision was provided by the Army personnel. However, the Center Director still maintained his control of the project by regularly dis- cussing her progress with her. The final evaluation of her report was done by the Director in consultation with the Army personnel. Hamsters were used as test subjects in this case. The student had to spend a large portion of her time under CHEMICAL ENGINEERING EDUCATION close supervision getting familiar with the testing pro- cedures and the handling of the animals. These were done in a closely supervised manner. After two years' experience, we find the operation of the Center very encouraging. Excellent cooperation has been provided by Natick Laboratories personnel. They have highly praised our students in terms of their working habits as well as their intelligence. The experience was viewed by the students as very valuable. As the WPI Plan moves into full operation at the upperclass level, project work is expected to consume about half of the total time of the faculty devoted to undergraduate education. The experi- ences to date in involving chemical engineering students in a wide variety of activities suggest that the transition, though not simple, will be suc- cessful. D CHEMICAL ENGINEERING AT BERKELEY (Continued from page 10) Thermodynamics Experimental and statistical thermodynamic analysis of fluid mixtures. Liquid crystalline behavior and other phase equilibria. Interfacial phenomena. Equations of state based on molecular properties. Electrolyte dissociation and ac- tivity-coefficient behavior. Adsorbed state of diatomic molecules. (Bromley, Lyon, Newman, Pigford, Prausnitz, Redlich). Transport Phenomena Fluid Mechanics. Laminar-flow systems. Rheology of poly- meric systems. Flow of molten alloys. Mechanics of sus- pended particles. Properties of liquid films. Wave propaga- tion in dispersive media. Mixing and dispersion phenomena in liquids. Drag reduction. (Donaghey, Goren, Newman, Shen, Vermeulen, Wilke, Williams). Heat Transfer. Nucleate boiling. Promotion of dropwise condensation. Boiling enhancement by additives. Direct- contact heat transfer between immiscible liquids. Thermal conduction of solids. (Bromley, Donaghey, Goren, King, Lyon, Wilke, Williams). Mass-Transfer Fundamentals. Transport properties of con- centrated electrolytes. Absorption with chemical reaction. Atmospheric spread of pollutants. (Grens, Newman, Pig- ford, Vermeulen). Separations and Mass Transfer Gas-liquid mass transfer and accompanying interfacial effects. Computation methods for distillation, extraction, and absorption. Separations of fine-particle systems. Ab- sorption and ion exchange. Oscillatory processes. Foam fractionation. Membrane separations. Separations by freez- ing. (Goren, Grens, Hanson, King, Klein, Lynn, Merrill, Pigford, Sherwood, Vermeulen, Wilke). S book reviews Chemical Engineering Thermodynamics: The Study of Energy, Entropy and Equilibrium, R. E. Balzhiser, M. R. Samuels, and J. D. Eliassen, 696 pp. Prentice-Hall, Inc., (1972). Reviewed by T.S. Storvick. University of Missouri-Columbia The significant flux of thermodynamics text- books into the technical literature suggests that there is a general dissatisfaction between authors of these books and those who use them. This book appears to have been conceived in this atmosphere. The evolution of thermodynamics textbooks indicates that they must now contain the classical material and some new elements: * It must be written for readers from more than one discipline. * The particle theory matter must be used in the logical development of the subject. * The use of electronic computers must be demon- strated. * Thermodynamics of irreversible processes must be introduced. The authors have written for Mechanical and Chemical Engineering students( the title is un- fortunate in this sense), they have used combi- natorial and probability arguments to introduce the entropy function, provided computer codes for several of the calculations in the worked ex- amples and concluded with a short chapter in- troducing irreversible thermodynamics. To this reviewer, the relationship that exists between the authors of thermodynamics textbooks and their readers is similar to that of a chef and the clientele of his restaurant. The basic ingredi- ents are always the same but the menu, the di- vision into courses, the spicing and flavoring, and the service and atmosphere are all designed to enhance the practical experience of eating. A satisfactory relationship is established when there is a match between cuisine and palate. It is the same with textbooks. Most undergraduate engineering students should learn to use classical thermodynamics in their first course on the subtect. This book is written for that audience and the authors provide over 90 worked examples and 225 exercises for the student. Some of the exercises will require considerable time to complete. The text is clearly written, the illustrations are generally useful and WINTER 1974 there appears to be very few troublesome typo- graphical errors. The order of presentation is conventional in nearly all respects (except for the introduction of of the entrophy function discussed below). The thermodynamic functions are introduced in the early chapters, the sections on work producing cycles and fluid flow are expanded to accommodate the needs of the mechanical engineering student. The final 215 pages are devoted to physical and chemical equilibrium of mixtures. A 20 page intro- duction to the currently important electrochemical processes is also included. There are some features of the book that may be related to matters of "taste" that this reviewer feels should be discussed in more detail. The mathematical structure of classical thermody- namics is disarmingly simple to undergraduate students who have completed much of their for- mal work in mathematics. Their concurrent ex- perience with dynamical mechanical systems and the rate processes that are described by more complex mathematical formalism adds to this confusion. The authors never clearly state what experiments establish the relationship of internal energy, volume and composition to the equilibrium state of a system. The mathematical form of the internal energy function as it passes through successive equilibrium states as work is done by the system and heat is added to it is left implicit. This may cause the student more trouble as he seeks to find the relationships between physical systems and the thermodynamic func- tions. It is an open question whether statistical ther- modynamics should be taught to undergraduate engineering students in their first thermody- namics course. The authors use the mathematics of permutations and combinations to compute the number of distinguishable configurations of a mascroscopic thermodynamic system. They then compute the probability pi that a particular con- figuration will be found and say, after Boltzmann, that the entropy of that configuration is given by Si = k in Pi. The equilibrium state is then proclaimed to be the one with the maximum probability, pi,..nx (and therefore the maximum entrophy S,) consistent with the constraining conditions that there be N particles in volume V with total energy E. None of the statistical thermodynamics formalism is developed and therefore, all of the real compu- national power of statistical thermodynamics is lost. The Carnot cycle is used to establish the relationship between reversible heat flow, the thermodynamic temperature and the entrophy. It is never clearly established that the total en- trophy change for all spontaneous processes must be positive and that this is the criteria for all the equilibrium considerations used in later chapters. This presentation does not appear to be a useful way to introduce the entropy function and it can- not be called an introduction to statistical ther- modynamics. One can ask, would it not have been better to use the postulatory approach of Cullen? (Thermodynamics, H. B. Cullen, John Wiley, New York, 1960, p. 24-25). This approach es- tablishes the central role of the state function in the mathematical formalism of thermodynamics. It then yields the processes ( work and heat flows, mass flows, etc.) by differentiation of the state functions. On page 52, the authors have listed nearly all of the necessary equations to implement this approach. It is still necessary to make the identifications between the mathematical func- tions and the physical systems that an engineer must make. But, as the authors say, "The utility of the entropy concept depends on relating it to the changes with which we as engineers are involved. Since our concerns are generally macro- scopic in nature, it is necessary to associate en- tropy with marcoscopic phenomena, such as heat and work, so that it can be used in the analysis of processes involving these energy flows and interconversions" (page 129). Since the authors follow the phenomenological approach everywhere in their book except for the introduction of the entropy function in Chapter 3, the postulatory approach would be consistent with the presenta- tion they have made. It is also true that the macro- scopic descriptions of statistical thermodynamics must be inferred from macroscopic experience whether it is taught before or after a course in applied macroscopic thermodynamics. There are some specific comments about the presentation that should also be made. The au- thors have chosen to use the general energy bal- ance for an open system to introduce the relation- ships between heat and work and the other terms in that balance. The discussion that fol- lows does not establish the important and startling mathematical fact that a conservative or state function, or exact differential of the internal energy written in terms of the physical parame- CHEMICAL ENGINEERING EDUCATION ters (for instance, temperature, volume, and com- position) is always equal to the heat added to and the work done by the system! Both the heat and work terms are path dependent functions. Once this has been established and is clearly under- stood by the student, the addition of potential and kinetic energy terms to obtain the general energy balance should cause little difficulty because the students have studied Newtonial mechanics. The treatment of the entropy function pro- ceeds by writing an entropy balance. It is in- ferred, but never clearly shown or stated that the entropy is a state function of the same thermo- dynamic coordinates as the internal energy. The authors use the "lost work" term to account for irreversibilities in a process and therefore do not state the powerful mathematical relationship for all spontaneous processes. f ] = dSTota 0 Subsystems T rev ota The authors then write (page 161) ". .. the third basic equation of thermodynamics (the energy balance and the entropy balance are the other two) dU = ds - P dV syst syst syst syst syst This is not a third basic equation but rather the combined first and second law equations. The authors incorrectly state (page 362) that c n nidGi = 0 i=-i is the Gibbs-Duhem equation rather than the previous equation C SnidG = VdP - SdT. i=l The development of the procedures to compute the fugacity coefficient (page 373) does not ex- plicitly state that the integration must proceed on an isotherm (although the original partial deriva- tive that is integrated is clearly marked as taken at constant temperature). Further ". . . to elim- inate computational difficulties in the limit P*-O0, we subtract the equation P In(P/P*) = 1 dP from P* /P) P* P* In f/P = -T dP." RT P P* This is a mathematical problem and the inte- grand in this final equation still appears to di- verge at P->P*'-,O even with the reassuring statement "we anticipate no further problems arising in the limit P*--O because the right-hand side remains bounded as P becomes small." This statement could have been made explicit by sub- stituting the compressibility factor z/p = V/RT and using L'Hopital's rule to obtain ,i0. ( Z 1 (- Lim where B(T) is the second virial coefficient, a well defined experimental quantity. This proce- dure not only provides a satisfactory mathemati- cal answer to the problem but provides an analytical method for making the extrapolation. It is clearly much easier to criticize a book than to write one. The authors have presented their method for presenting thermodynamics to engineering students. They have found this treat- ment to be successful and this success can only be judged by allowing students to read the book. Their tastes and appetites are nearly always dif- ferent than those who grew up a decade or two ago. DEPARTMENT CHAIRMEN If you have not renewed your departmental sub- scription to CEE for 1974, please write R. B. Ben- nett, Business Manager, CEE, Department of Chemical Enginering, University of Florida, Gainesville, Florida 32611. BULK SUBSCRIPTION RATES: $4/yr. each, with a $25.00 minimum for six or fewer sub- scriptions. ASEE-CED & AIChE MEMBERS INDIVIDUAL SUBSCRIPTIONS are available at $6/yr. (Regular rate $10/yr.) WINTER 1974 WATERLOO PROGRAM FOR HIGH SCHOOLS E. RHODES University of Waterloo Waterloo, Ontario "W HAT'S THE DIFFERENCE between SChemistry and Chemical Engineering?" That's a question often asked by high school stu- dents (and teachers and guidance counselors) when they are seeking out a career with a chem- istry bias. We have even been asked the question by students who have already chosen to study chemical engineering. The question is no doubt symptomatic of the lack of communication be- tween schools and chemical engineering depart- ments which, to my mind, has arisen because traditionally we could attract all the students we wished to enroll and we were definitely blas6 about recruiting. Times have changed however, and now departments are worried about falling enrolments and the solid decline in the overall number of stu- dents wishing to study engineering in general and chemical engineering in particular. We must com- municate with the schools and somehow we must get across to students and teachers the attractive- ness of chemical engineering as a study discipline and career opportunity. In return we need to be educated in the changing patterns of high school curricula so that we are flexible and agile enough to adjust our courses to accommodate the needs and abilities of the new Freshmen. How can we open up this line of communication. No doubt there are many ways tried by many departments across North America and the world. The Waterloo programme was inspired by my sabbatical experience at the University of Queens- land, Australia, where I was called upon to take part in the Chemical Engineering High School Day Programme. This kind of educational pro- gramme is aimed at challenging small numbers of interested students to seriously learn about chemical engineering and consider the profession as a career opportunity. In our High School Pro- gramme we do not invite busload after busload of uninterested students to the campus and deliver a pep talk, a movie, and a donut in the hope of catching a few. Instead, we send out a limited number of invitations to those students who have We must communicate with the schools and somehow we must get across to students and teachers the attractiveness of chemical engineering as a study discipline and career opportunity. a curiosity (be it mild or strong) about chemical engineering. On a typical High School Day we can entertain about 33 students from outside the university. To these we add 11 of our own volunteer first-year undergraduates, several professors and some graduate student demonstrators. Small groups consisting of three high school students and one undergraduate, tackle four experiments selected from a total offering of eleven. Each experiment takes about one hour to complete and the students have to do the work themselves, although Profes- sors are close at hand to introduce the basic prin- ciples of the experiments and answer questions. The experiments have been developed by the Pro- fessors of the department and strongly reflect their own interests, thus illustrating the breadth of the Waterloo degree programme and the scope of Chemical Engineering. EXPERIMENTS TO CHALLENGE HIGH SCHOOL STUDENTS 1. Expansion of the Kitchener waste treatment plant (P.L. Silveston). The object of the experiment is to illustrate what goes into process design and how one sets about it. The experiment gives the student a brief introduction to pollution control, computers and computer-aided design. In the explanation of the experiment (we have a High School Programme Manual) the concept of a process system is ex- plained by reference to the present Kitchener (Ontario) Sewage Treatment Plant. It is then shown how the plant can be simulated by use of a digital computer programme. At this stage the CHEMICAL ENGINEERING EDUCATION existing programme is handed over to the students and they are requested to find out: * If the present plant is capable of handling 95' of the Biological Oxygen Demand and Sus- pended Solids expected in 1985; * What will be the effect of adding cylindrical tanks in the settlers or rows of square tanks to the aerators; * What will be the cost to expand the city of Kitchener Plant to meet the 95'/; target. 2. Enzyme Catalysis (J.M. Scharer)*. Intended to illustrate the involvement of bio- chemical applications of chemical engineering, the student is asked to determine the Michaelis- Menten constant for a particular enzyme reaction and the maximum reaction rate for a given enzyme concentration. The reaction studied is k k H20 + E > X - 2O +1/2 2 + E k in which E represents catalase, and X an en- zyme-HO, complex. The catalase is synthesized by use of bacteria such as E. coli, B. subtilis, S. Faecalis and S. Aureus, while the evolution of oxygen indicates the presence of the enzyme. Hav- ing determined the two constants from the system the students are asked: * To explain why most aerobic organisms can synthesize catalase; * How a change in enzyme concentration would affect the experimental results. 3. Analog Computation in Chemical Engineering (K.S. Chang). A short presentation is given to the students in which the general purpose analog computer is described as an orderly collection of amplifiers, potentiometers, resistors, capacities etc. The patch board is introduced and the students are asked to patch up the circuit to be used for generating the 4 sin t and 4 cos t functions. The signals are dis- played on an oscilloscope and an X-Y recorder. Among other questions, the students are asked: * Why the signals produced by the circuit are 4 sin t and 4 cos t. * To develop a circuit diagram which would gen- erate 4 sin(lOt) and 4 cos(lOt). :Gorber, D.M. and Scharer, J., CEE 5 (2), 141 (1971). 4. An Advanced Analog Computation Problem (T.Z. Fahidy). Following on from experiment (3) the stu- dents investigate the oscillatory behaviour of the Van der Pol Equation. Having done this the stu- dents then go on to: o Sketch the shape of the limit cycle at various potentiometer settings and describe the findings. * Discuss the practical use (if any) of such an electronic circuit. 5. Elastomers-A Fourth State of Matter? (B.M.E. Van der Hoff). After a general introduction to the concept of viscoelasticity and the chemistry of rubber, the students use an Instron tester to investigate the properties of natural rubber and polyvinylchloride softened by the addition of oil. For example an elastic band is elongated in the machine and the force acting on the band is measured against time at constant elongation. The sample is then heated We sent out a limited number of invitations to those students who have a curiosity about chemical engineering. and the experiment repeated. Hysteresis is meas- ured in the form of a force-elongation curve. Typ- ical questions asked of the students are: * What is the value of the initial modulus at small elongation and the modulus just before break? o Why is the area of the hysteresis loop larger for the polyvinylchloride than for the natural rub- her? " Why does a sample not return to its original length? 6. Experiments Demonstrating some Industrial Electro- Chemical Processes (K. Enns). The objects of this experiment are to demon- strate a) the electrowinning of copper, b) electro- etching and c) brass electroplating. It is explained that all electrochemical processes found in extrac- tive metallurgical, metals refining and finishing industries involve cells containing anodes and cathodes. The students find out by experimenta- tion the amount of copper won per kilowatt hour and calculate the energy cost per ton of copper. Then by building a cell using graphite for the anode and a partially covered copper sheet for the cathode, electroetching is discovered, and the WINTER 1974 amount of copper removed during the etching process is calculated. Finally another cell using a sheet steel cathode and a brass anode is built to enable the plating of the steel. Cu-Zn-cyanide solu- tion is used in this experiment. Typical of the questions posed to the students at the end of this session are: * Why is brass plated from a Cu-Zn cyanide solu- tion ? * Why not plate brass from a much less poisonous CuSO,-ZnSO, solution? 7. Waste Water Renovation by Ion Exchange and Ad- sorption (K. Enns). This experiment is designed to demonstrate the demineralization of water by cation anion ex- change and colour removal by adsorption. A "waste water" sample is renovated firstly by ex- changing all positively charged ions in the waste by H+ using a cation exchanger. After testing for metals by atomic absorption, the solution is treated with an anion exchanger and then ac- tivated charcoal. By now the original murky solu- tion is quite clean. The students are asked typ- ically: * Is it economically feasible to use ion exchangers to treat concentrated solutions? * Can you suggest a reason why ion exchangers generally prefer (are selective for) bivalent and trivalent species over univalent species? 8. Determination of Lead in Gasoline by Polarographic Analysis (K. Enns). Here the students find out what is meant by the polarographic method of analysis and deter- mine the concentration of lead in a typical sample of gasoline. The significance of the typical 'S' shaped polarogram is explained and the students firstly calibrate a machine by making up a known sample containing lead nitrate, and secondly, in- vestigate the unknown gasoline sample previously extracted into an aqueous solution. Typical ques- tions to round off the session are: * In what form is lead usually present in gasoline? * Why can't we carry out polarographic analysis directly on the gasoline sample? 9. Determination of a Chemical Reaction Rate Constant By Thermal Analysis (K. Enns). By a simple thermal analysis method the re- action rate constant of the catalyzed reaction be- tween n-butanol and phenyl isocyanate is deter- mined. The principles of heat of reaction and re- action kinetics are explained, and the students after being presented with an adiabatic reactor (thermos flask), magnetic stirrer, thermometer and automatic delivery syringe are put to work. The students are asked typically: * Is it reasonable to assume that the thermos flask approximates an adiabatic reaction? * Is the rate constant data obtained in this way useful? Or is it just an academic exercise? 1C. Measurement of Liquid Flow (J. D. Ford). It is explained that an important problem fre- quently encountered by engineers is that of meas- uring the rate of flow of a liquid. Whether it is the flow of a river or the flow of water into a kitchen sink, a few simple principles enable such measurements to be accurately made. The students are asked to investigate the use of an orifice for One student presented the enzyme experiment in the form of a series of cartoons of whale-like bugs gobbling up molecules and burping up the new ones all over the place. measuring the flow from a large variable head tank. The students discover the relationship be- tween mean velocity in the orifice and head of fluid and are finally asked the following: * A one pound ball falls to the ground from a height of 2 ft. At what velocity does it hit the ground ? o Considering the above question is related to our graph of log (velocity) versus log (head), what is the theoretical value of the exponent n in the relationship (velocity) a (head)". 11. Flow Through Porous Media (F.A.L. Dullien). In part one of the experiment the students are set the task of measuring the permeability of a porous material consisting of a packed bed of glass beads or sand by establishing the relationship be- tween pressure drop and flow rate across the sample. In the second part of the experiment the students observe the phenomenon of dispersion by use of a dye tracer injected into the flow of a packed bed. Typical questions are: CHEMICAL ENGINEERING EDUCATION * What is the permeability of a non-porous sub- stance? * What factors may influence dispersion in porous media? BULL SESSION When each group has completed four experi- ments it must prepare a two minute verbal report on the final experiment. This report is presented at the closing session of the day. Half an hour is allotted for report preparation and the usual vis- ual aid materials are provided for the assistance of the students. The reports have been remarkable for several reasons. For example, the students have been seen to respond amazingly well to the challenge and have quickly learned the principles on which the experiments are based. Secondly, it has been worth noting how interesting and often amusing the students have made their two-minute presentations. One student presented the enzyme experiment in the form of a series of cartoons of whale-like bugs gobbling up molecules and burp- ing out new ones all over the place. Each group having made one report, the whole programme of eleven experiments is covered and the final half hour is devoted to informal open dis- cussion. It has been our experience that at this stage, most of the barrier of shyness has been broken down and everyone is anxious to get a word in. Our own undergraduates make a big con- tribution to the discussion. Marilyn was a very glamorous first-year chemical engineer in 1971 and she came to all our High School Days in flam- ing hot pants. When one High School threw out the question "What was it really like to be a chem- ical engineering student?", it was answered by Marilyn with a very eye-catching gesture and one word "Fabulous." Despite the fact that from then on, the Professors thought Marilyn was our best advertisement, she left us at the end of the year for academic reasons, a very sad departure for one and all. EFFECTIVENESS OF THE PROGRAMME So far the only method of measuring the ef- fectiveness of the programme has been to ask the students for their opinions at the end of the day and to observe the reactions of both students and professors in the laboratory and in the culminat- ing group discussion. Nearly all the students responding to a ques- tionnarie say the programme is suitable for One fellow suggested we insert a steak dinner into the program and another felt the program would be helpful for his school teachers. Grades 12 and 13 High School Students but not for Grade 11. Most of the experiments were judged to be correct level of difficulty, although most problems were caused by the analog com- puter experiments and least difficulty was experi- enced in the waste water treatment and fluid flow experiments. Many students would have liked an extra day to do all the experiments and most felt they had learned a lot. Several students indicated that the opportunity for discussion was a very im- portant factor contributing to the success of the programme. One fellow suggested we insert a steak dinner into the programme and another felt that it would be very beneficial for his school teachers. This last comment prompted us to invite the local School Teachers' Federation to include an evening of working in our laboratories on their Professional Development Programme. One such evening has now been held with enormous suc- cess. The format was the same for the teachers as it was for the students and the closing discussion provided a real opportunity for the exchange of ideas on education. It has been mentioned that first year under- graduates were also used in the programme. Their reaction has also been very positive and we are considering offering the programme to all the Freshmen during registration week. Its purpose here will be to break down the barriers between Faculty and students almost before they have time to be erected, and to motivate the students by pro- viding them with a broad view of the department at the very beginning of their university career. Does our programme answer the question "What is the difference etc .... "At least it il- lustrates the breadth of interest of chemical engi- neering, which we believe is one of its most at- tractive features. It also provides a forum where all kinds of people by working together, find com- municating questions, answers and ideas to be very easy. The High School Programme Manual can be obtained by writing to Professor E. Rhodes, Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada. Please enclose a cheque for $2.00 to cover the printing and post- age costs. The cheque should be made payable to Chemical Engineering, University of Waterloo. ] WINTER 1974 A JUNIOR COURSE IN CHEMICAL ENGINEERING COMPUTATIONS E. M. ROSEN Monsanto Co. St. Louis, Missouri - N THE SPRING of 1973 the author was asked to develop a three unit course in chemical en- gineering computations based on the text "Ma- terial and Energy Balance Computations" by E. J. Henley and E. M. Rosen.1 This was to be the sec- ond semester course in the two semester Elements of Chemical Engineering sequence for third year chemical engineering students at Washington University, St. Louis. It was a listed prerequisite for the senior Systems Analysis and Design course. Typically at this stage, students have had a course in thermodynamics, and a course in the use of mathematics and the methods of engineer- ing in the analysis of chemical and physical proc- esses. In addition, they have had a course in basic chemical process principles including stoichio- metry, ideal gas law and gas mixtures, vapor pressure, solubilities and energy balances. Only those interested (about 1 3 to 1 2 of the stu- dents) had taken the optional one unit digital computer programming course. In general, the student had not used the computer as an integral part of his previous course work. The traditional unit operations courses covering such topics as distillation, absorption and heat transfer were no longer offered, though a two semester junior se- quence in transport phenomena was a listed re- quirement. The basic approach to the material in the text has been described previously.' Major emphasis was given to the machine methods chapters in the text, chapters 5, 8 and 9. Table 1 gives the general outline of the course and the number of sessions devoted to each topic. Each session was scheduled for 75 minutes twice a week in the evening hours. Almost one third of the course was devoted to graphical methods in distillation and absorption. This was done in part to fill the lack of exposure to the unit operations. Outside reading:'- was used in support of this portion of the course in addition to the use of a secondary text." Edward M. Rosen received his BS and MS from the Illinois Institute of Technology and his PhD from the University of Illinois. Currently he is a Science Fellow and Manager, Systems Technology at the Monsanto Co. where he has been since 1959, except for a postdoctoral academic leave at Stanford University in 1962-3. With E. J. Henley, he is co-author of the text "Material and Energy Balance Computations". (John Wiley, 1969) CONDUCT OF THE COURSE THE COURSE WAS A traditional lecture type with homework (which was not graded) as- signed from the text or specially designed and handed out. In addition the class was divided into teams of three persons each for the purpose of doing the five computer problems that were as- signed and which formed 20''4 of the course grade. The reason for the teams was two-fold: * Some members of the class did not know FdRTRAN programming. * It was desired to hold the computing bill down. Eight one hour exams, of which only the highest six were counted, (60%' of grade) were given, plus a final (20% of grade). The comparatively large number of exams was designed to prevent members of the class from falling behind and to provide them a means of gaining new insights to the topic areas. The number of exams received little class criticism though not grading the home- work (though it was always discussed) appar- ently gave the students little motivation for doing it. CHEMICAL ENGINEERING EDUCATION THE COMPUTER PROBLEMS T HOUGH THE COMPUTER problems were intended to be a major portion of the course they were weighted comparatively lightly since knowledge of FORTRAN was not a course pre- requisite. It was intended that every member of each team would participate equally in the com- puter problem analysis and that those members knowledgeable in coding would teach the un- knowledgeable ones. This, it was felt, closely TABLE 1-COURSE OUTLINE Session Numbers Topics Part A. Chemical Process Calculations 1-2 Course Conduct 3 4-5 6-7 8-9 10 11-12 Part B. Distillation 13-14 15-16 17 18-19 Part C. Plant Simu 20 21 22-23 24 25 26 WINTER 1974 Review of General Energy and Ma- terial Balance Equations Matrices and Vectors Independence, Orthogonalization and Rank. Solution of Linear Equations and Material Balances The One Dimensional Nonlinear Equa- tion and Flash Calculations Chemical Reactions and Their Inde- pendence. The Extent of Reaction. Chemical Equilibrium Energy Balances: Adiabatic Flash and Adiabatic Flame Temperatures. and Absorption Binary Distillation-The McCabe- Thiele Method. Minimum Stages and Minimum Re- flux. Analytical Shortcut Methods. Multicomponent Methods-Tridiagonal Equations Absorption-Graphical and Analytical Methods nation Streams and Building Blocks The Split Fraction Concept Partitioning and Tearing Equations. The Convergence Block Concept Direct Substitution and Wegstein's Method Information Feedback Comprehensive Flow Sheet Calcula- tions The intent was for the student to formulate the problem, code the main program but let the subroutine do the tedious work of computation. paralleled the environment found in industrial organizations. Each member of the team was re- quired to hand in a problem analysis though only one computer output per team was required. How- ever, this did not turn out satisfactorily, since the knowledgeable FORTRAN students spent a dis- proportionate amount of time coding and debug- ging the computer problems while the others spent comparatively little time. At the start of the course source decks for the four FORTRAN subroutines listed in the rear of the text' were handed out to each team. (This was necessary since only the WAT IV com- piler which required all source coding could sup- ply adequate turnaround). The four subroutines supplied to each team were: GSMT GELG ROOT BSOLVE Gram Schmidt Orthogonalization Simultaneous Linear Equation Solver One dimensional Root Finder Simultaneous Nonlinear Equation Solver The intent was for the student to formulate the problem, code the main program but let the sub- routine do the tedious routine work of computa- tion. The five problems were either formulated by the author or adapted from the recently released CACHE committee volume of computer programs on Stoichiometry." Table 2 lists the titles of the problems for the course and the subroutines which were to be used. COURSE EVALUATION A TOTAL OF ELEVEN students enrolled in the course and were asked to fill out a ques- tionnaire at the conclusion of the course. The questionnaire asked the student to rate each of the computer problems for instructive value and interest. Other questions relating to the useful- ness of the computer problems and course organ- ization were then asked. Finally the student's re- sponse to specific topics was queried. Table 3 lists the raw responses of the class to the question- naire. Overall the course elicited a broad range of rather strong responses. Students with an ade- quate computer background appeared to respond favorably while those without the background appeared to be much less satisfied. There appears little question that a prerequisite for the course should be coding proficiency in F(bRTRAN by all participants. Efforts were made continuously to relate the numerical methods portion of the course to direct application. REFERENCES TABLE 2-COMPUTER PROBLEMS Problem Description 1. A. Inconsistent and Incomplete Material Balances' B. Linear Material Balances' 2. Flash Vaporization 3. Simultaneous Gas Phase Equilibrium Reactions 4. Theoretical Maximum Flame Temperature' 5. Recycle Calculations Using Split Fractions Use of Subroutine GSMT GELG ROOT BS4LVE ROOT GELG 1. Taken from Reference (6), p. 85, 147. 2. Adapted from (6), p. 198. 3. Copies of the problems may be obtained from the author on request. The use of teams seems to be little justified. Students complained that only one person on the team did all the work and were not sufficiently credited for their effort. There seemed little basic difficulty with the level of the course material in the text though some complaints were recorded about its clarity in places. Efforts were made continuously to relate the numerical methods portion of the course to direct applications though it should be noted that the text separates these functions for ease of refer- ence and development. This meant considerable jumping around in the text and required care- fully planned reading assignments. Rather strong interest was displayed in the unit operations section of the course as evidenced by the desire for more time to be spent in this area. No time was spent on heat transfer calcula- tions and this would certainly be an area for course expansion. Whether or not the course was best separated into its three distinct parts or could better be integrated into a single topic called process simulation is unclear at this time. D 1. Henley, E. J. and Rosen, E. M. MATERIAL AND ENERGY BALANCE COMPUTATIONS John Wiley (New York), 1969. 2. Rosen, E. M. and Henley, E. J. "The New Stoichio- metry" Chem. Eng. Ed., Summer 1968. 3. Smith, B. D. DESIGN OF EQUILIBRIUM STAGE PROCESSES McGraw Hill, 1963. 4. Van Winkle, M. DISTILLATION McGraw Hill, 1967. 5. Henley, E. J. and Staffin, H. K. STAGEWISE PROCESS DESIGN John Wiley, 1963. 6. Henley, E. J., Editor, COMPUTER PROGRAMS FOR CHEM- ICAL ENGINEERING EDUCATION-STOICIIIOMETRY Sept. 1972. TABLE 3-RESPONSE TO QUESTIONNAIRE Questions 1-5: Computer Problems Material Equi- Max. Split Balance Flash librium Temp. Fraction Very Instructive Instructive Adequately Instructive Not Instructive Very Interesting Interesting Fairly Interesting Dull, Dull 1 3 2 1 8 5 6 5 3 2 3 2 1 4 5 6 1 3 4 3 2 4 6 3 1 1 1 6. The computer problems Added substantially to the course. 4 Added to the course 4 Added marginally to the course 3 Detracted from the course 7. Supplying the subprograms Was very useful and did not detract from the problems 10 Was useful but made the problems less instructive - Marginally useful 1 Was a poor idea CHEMICAL ENGINEERING EDUCATION I � � _I III 8. The course was Well organized Fairly well organized Adequately organized Poorly organized 9. Topic A. Phase equilibrium B. Inconsistent material balances C. Chemical reactions D. Distillation E. Absorption F. One dimensional equation solving G. Multi-dimensional equation solving H. Plant simulation I. Matrices and vectors J. Energy balances K. Independence and orthogonalization Should be Ex- Re- anded duced 3 2 1 About Right 8 7 5 5 1 Dropped 1 4 6 4 2 7 5 1 1 6 1 5 CHEMICAL ENGINEERING 0 DIVISION ACTIVITIES 3M COMPANY INCREASES LECTURESHIP AWARD GRANT The 3M Company has increased its annual grant in support of the Chemical Engineering Di- vision Lectureship Award from $1500 to $2500. The additional $100 will cover an honorium and expenses to allow the awardee to present his lec- ture and visit on the campus of three institutions to be selected by the Chemical Engineering Di- vision. The increased funding is effective begin- ning with the 1974 award. The suggestion for the new visitation program was made by Prof. L. E. Scriven of the University of Minnesota, a former award winner and trans- mitted to 3M by Prof. Leonard Baker when he served as Division Chairman. Announcement of the increased support was made by W. W. Burton of 3M to Dr. George Burnet of Iowa State Uni- versity, who participated in the discussion with 3M and was instrumental in obtaining the orig- inal grant from that company. [JIUI lyIlHIIllt^ Parsons is a Good Place to Work! There is no limit to the opportunities offered by Parsons-high salaries, good benefits, ad- vancement, professional freedom-and a work environment unequalled anywhere. Parsons is expanding its operations. Our new world headquarters will be completed in the summer of 1974. This $20 million, 400,000 square-foot facility was designed specifically for our business. It is located in a suburban area near the Rose Bowl in Pasadena, Cali- fornia, close to some of the country's famous universities in case you want to further your academic career-with Parsons' tuition aid plan. Parsons is one of the leaders in the engineer- ing design and construction of petroleum re- fineries, metallurgical plants and chemical plants. We have prepared a booklet describing the advantages of working for Parsons-for your copy of "Parsons is a Good Place to Work," write to Personnel Manager, The Ralph M. Parsons Company ENGINEERS/CONSTRUCTORS 617 West Seventh Street, Jl Los Angeles, Ca. 90017 AN EQUAL OPPORTUNITY EMPLOYER WINTER 1974 ACKNOWLEDGMENTS INDUSTRIAL SPONSORS: The ollowina companies donated a d jo4 dhe d"uppfoa o CHEMICAL ENGINEERING EDUCATION d$uing 1973: C F BRAUN & CO MONSANTO COMPANY THE 3M COMPANY DEPARTMENTAL SPONSORS: h14e joUowain 129 depi.atmen.t coat'&dlte at tie dapp(at o& CHEMICAL ENGINEERING EDUCATION in 1973 University of Alabama University of Akron University of Alberta Arizona State University University of Arizona University of Arkansas Auburn University Brigham Young University University of British Columbia Bucknell University University of Calgary University of California (Berkeley) University of California, Davis University of California (Santa Barbara) California Institute of Technology Case-Western Reserve University City University of New York Clarkson College of Technology Clemson University Cleveland State University University of Colorado Colorado School of Mines Columbia University University of Connecticut Cooper Union Cornell University University of Delaware University of Detroit University of Denver Drexel University Ecole Polytech, Canada University of Florida Georgia Institute of Technology University of Houston Howard University University of Idaho University of Illinois (Urbana) Illinois Institute of Technology Iowa State University University of Iowa University of Kansas Kansas State University University of Kentucky Lamar University Laval University Lehigh University Loughborough University (England) Louisiana Polytechnic Institute Louisiana State University University of Louisville McGill University McMaster University McNeese State University University of Maine Manhattan College University of Maryland Massachusetts Institute of Technology University of Massachusetts University of Michigan Michigan State University University of Mississippi University of Missouri, Columbia University of Missouri, Rolla Montana State University University of Nebraska Newark College of Engineering New York University University of New Mexico University of New Brunswick University of New Hampshire University of New South Wales New York University North Carolina State University University of North Dakota Northwestern University University of Notre Dame Nova Scotia Technical College Ohio University Ohio State University University of Oklahoma Oklahoma State University Oregon State University University of Ottawa University of Pennsylvania Pennsylvania State University University of Pittsburgh Polytechnic Institute of Brooklyn Princeton University University of Puerto Rico Purdue University University of Quebec Queen's University Rensselaer Polytechnic Institute University of Rhode Island Rice University Rutgers-The State University University of Rochester University of Southern California South Dakota School of Mines State University of N. Y. at Buffalo Stevens Institute of Technology Syracuse University Technion, Israel Tennessee Technological University University of Tennessee Texas A&I University University of Texas at Austin Texas A&M University University of Toledo Tri-State College Tufts University University of Tulsa University of Utah Vanderbilt University Villanova University University of Virginia Virginia Polytechnic Institute Wayne State University Washington State University Washington University University of Washington University of Waterloo West Virginia University University of Wisconsin Worcester Polytechnic Institute University of Wyoming Yale University Youngstown State University University of Windsor TO OUR READERS: If your department is not a contributor, please ask your department chairman to write R. B. Bennett, Business Manager, CEE, Depart- ment of Chemical Engineering, University of Florida, Gainesville, Fla. 32611. Bulk subscription rates at $4/yr each with a $25.00 minimum for six or fewer subscriptions. Individual subscriptions are available to ASEE-CED and AIChE members at $6 yr. CHEMICAL ENGINEERING EDUCATION What goes up must come down. - ,i-. The tires of most jetliners lose traction on a half inch of snow. That means runways must be kept free of snow and ice. Or airports must close and the planes land somewhere else. Which causes a lot of inconvenience for passengers. Strange hotels. Long lines. Missed relatives. And dreary hours waiting for better weather. But this winter the story may be dif- ferent. Because of Union Carbide's Runway De-Icer. We discovered a new combination of liquid chemicals that penetrates a cov- ering of snow and ice and unglues it from the runway surface. So it can easily be pushed away. It can also be laid down before a storm to act as an anti-icer. Last winter it was successfully used at over 20 busy metropolitan airports. This year we expect that more airports will be using UCAR Runway De-Icer. So now instead of just talking about the weather, people can do something about it. THE DISCOVERY COMPANY For additional information on our activities, write to Union Carbide Corporation, Department of University Relations, 270 Park Avenue, New York, New York 10017. An equal opportunity employer. ZEfffl In the energy field, there aren't any easy answers which is one very good reason for considering Atlantic Richfield for your career. It's energy that has created and maintains the fabric of today's civilization. That's basic. But getting and using energy has also created some very large and basic problems: air pollution, ecological disruption, resources depletion-to name a few of the obvious ones. Now, new answers must be found to developing and utilizing energy-and its by-products-if we are to maintain our energy-based standards of living. We want the best brains we can find to help us arrive at these answers. We want people sensitive to the human and natural environment-and realistic enough to know that preserving both must come from tough, intelligent, dedicated work... backed by outstanding resources in capital, research and experience, such as those of Atlantic Richfield. If tackling such large-scale, significant problems is one of your criteria in selecting a job, join us.We can offer you a career rich in challenge, rich in meaningful work, rich in personal reward. We typically offer opportunities to engineers, accountants, financial analysts, auditors, geologists, geophysicists, sales representatives and programmers. See our representative on campus or your Placement Director. AtlanticRichfieldCompany 0 An equal opportunity employer, M/F. - .. . . ".., . , - t'&" ,-. S- ... � -. " tll,,,- , .... .~;`b�LL,,aP' " " IC- " "-� -..Z_ ,~i~ -fJT, �"'~ ~1~T! --� -�r..; CL.. c �-, ~~a~ i. " *~T""�' .r. " -. "rU--:� - -- ~- "i~c~ |
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| 0 | sobekcm_database.verify_item_lookup_object | |
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| 0 | cached_data_manager.retrieve_item_aggregation | |
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| 65 | html_echo_mainwriter.add_text_to_page | Finished reading and writing the file |