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A Course in Fundamentals of Chemical Engineering for High School Science Teachers Gordon A. Lewandowskl and Reginald P. T. Tomklns New Jersey Institute of Technology, Newark, NJ 07102 For the past two years (1984 and 1985), a 16-week course on fundamentals of chemical engineering has been presented at the New Jersey Institute of Technology. The purpose of this course was to acquaint high school science teachers with an overview of chemical engineering as a profession, and with the fundamentals of chemical engineering practice. Although strongly rooted in mathematics, physics, and chemistw. chemical eneineerine is much more than a simple extrapdation of scienci. The Gagmatic applications of ihe profesuion rewire the development of distinct skills. When science is unable to provide the tools necessary fora satisfactory solution to a problem, experience and approximation techniques must he utilized. Furthermore, the~scaleof operations is very much larger than the hench-scale familiar to most scientists. This increase in scale presents peculiar problems of its own. And finally, economics plays a crucial role in eneineerine decisions. The need for th& type of program arose from discussions with high school science teachers who indicated that they had little or no knowledge about industrial applications of chemical principles. The general feeling was that the chemistry curr~culu&was todabstract andfailed to relate the subject to real life. In particular, there was a clear need to gain an appreciation of the factors involved in scaling up a laboratory to commercial operation. . experiment . As a result, a course was developed whose purpose was to enrich and strengthen the chemistry curriculum, enhance the teachine of chemistrv.. show how fundamental scientific concepts are transformed into technology, and increase the awareness of career opportunities and the challenges that students will meet in the chemical industry.
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Background One of the authors (RPTT) is currently serving as a member of the national committee of the chemical Industry for Minorities in Engineering (ChIME). This organization is sponsored by a number bf chemical and ph&naceutical companies and has as its objective an improvement in visibility of the chemical engineering profession, particularly among females and minority groups. In addition, NJIT is home to the Center for Pre-College Programs, a nationally recognized center for introducing urban high school students and their faculty to a university environment and its career benefits. I t was perhaps natural when both of these oreanizations co-snonsored the original offering of this co&e in the spring of 1984. The ~ J b e ~ a r t m eof n tHigher Education and Dow Chemical Co. were added as co-sponsors in the spring of 1985.
Cwrse Structure The course was presented once a week in the late afternoon for a period of 16 weeks. Participants were reimbursed for travel expenses to NJIT, and refreshments were provided before and during the classes. There were two principal instructors for the course, and guest lectures were given by four other facultv members with narticular ex~ertisein certain areas. ~ o m k i n (amember s of'thechemistri faculty) was the course administrator, and Lewandowski (a member of
318
Journal of Chemical Education
Table 1. Courm Schedule week 1 2 3 4 5
6 7
8 9 10 11 12 13 14 15 18
TOPIC
Orientation (including, Careers In Chemical Engineering) Material Balances I Material Balances 1 I Application af Thenmdynamics to Chemical Reactions Kinetics and Catalvsis industria aganic Chemioby 001 Refmlng and Pebochemlcals Energy Balances PoiiUtion Conhol Tour 01 WIT Research Labs, and Use of Computers in Chem. Eng. Plant Design I Plant Design I1 Labaatory Experiments Plant Vlsit Laboratory Experlmems Final Exam ~
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the chemical engineering faculty) has nearly eight years of nrior industrial exnerience. he course consisted of lectures, laboratory experiments, and a visit to a local chemical plant. A considerable amount of original course material was handed out to the participants. A final examination was given a t the end of the course, and weekly assignments were collected and graded. Three graduate credits were available for those participants who ~erformedsatisfactoriallv. There were 18 nartici~antsin kach of the two classes t i a t have been conducted thus far, and all but one had taueht chemistw. or . phvsics " . a t various stages of their careers. A listing of the course schedule is presented in Table 1.I t is seen that there is an attempt to balance some traditional topics in chemistry (such as thermodynamics, kinetics, and industrial organic chemistry) with more typical courses in chemical engineering (such as material and energy balances, process control, and plant design). The inclusion of the chemistry component was deemed necessary as many of the participants had not received a formal training in chemistry for some time, and also the chemical topics were described in such a way as to reflect their application to processes in the chemical industry. Anyone interested in obtaining more details about specific topics covered in the course should contact the authors. Examples of Toplca In the followine sections, some specific examples are presented to convey Loth the scope of [he course anh the level of achievemenr that was possible with the high school teachers who participated. Chemical Engineeringas a Career Enrollment and salary data were presented, as shown in Figure 1and Table 2. Universities are always a t least four years out of phase with the job market. A rising job market
"4,' Temrotura, keiv*n W T =do)
Figure 3. Wir%-and-plate elecbostatic precipitator.
Figure 2. Equilibrium constants in gasification reanions (i0
An examination of the plots of equilibrium compositions (Fig. 2) was used to find the most appropriate operating conditions and the need to consider using waste heat in order to improve the overall efficiency of the process. Klnetics and Catalysis
The concept of the use of catalysts for speeding up a reaction by lowering the energy of activation was familiar to most of the participants. The emphasis in this course was directed toward: (1) catalyst selection, (2) mechanisms of catalysis, and (3) the introduction of reactor residence time. Several examples were presented involving industrial reactions where more than one route was available. One example involved the Fischer-Tropsch synthesis of gasoline
where problems exist in separating the water or the COz from the product stream, and in deactivation of the catalyst by carbon deposition. Laboratory Experiments
in this course. Rather, we have created an imaginary company (the Consolidnted Chemical Co.) with the dass iktruLtor ~ l a v i n the r role of A. W. Robertson, I'rocess Design Manager. T h e students are divided into four-person g;oups that report to Robertson on a weekly basis. Process design involves taking the bench-scale discoveries of a chemist and subdividing them into individual steps called unit operations. Mixing, distillation, reaction, filtration, and heating or cooling, are examples of unit operations. In eeneral. each unit o~erationcorres~ondsto a ~ i e c eof equipment, which must be specified. Estimates can then he made of the total ~ l a u cost t and future ~ r o f i expectation, t Examples were pr;sented of the kinds of decisionsand skills required to design a process or operating plant. Blueprint drawings, developed in aformer life by one of the instructors (GAL), were used to illustrate the steps in the design sequence. Aside from the chemical engineering fundamentals involved in design, an important requirement is written communication, since a number of reports are required. Material and energy balances are also used extensively, emphasizing once again the need for algebra a t the high school level. In fact. these two subiects-Enelish com~ositionand aleebra-would be very high on our list of high school prerequisites for an engineering career.
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Some laboratory experiments were included in the course with the main aim being to allow the teachers hands-on experience in analytical techniques, such as gas chromatography and infrared spectroscopy. The use of these techniques was reinforced during a visit to an industrial lahoratory. The course participants were also given a tour of the undergraduate chemical engineering unit operations lahoratory as well as graduate research laboratories.
The highlight of the course was probably the plant trip. During spring 1985, we visited the Givaudan plant in Clifton, NJ, under the knowledgeable escort of John Schauhach, Proiect Engineer and NJIT alumnus. I t was very important to show a c&rete realization of the principles and approach described in the previous classes, and the participants enjoyed it very much.
Pollution Control
Partlclpant Feedback
Emphasis in the course was on the engineering aspects of pollution control, touching a n the design of control equipment such as scrubbers, bag filters, electrostatic precipitators, and secondary treatment plants. This was too much for asingle three-hour class, and we will expand this topic to two sessions in the future (see Participant Feedback). Figure 3 is a schematic of a wire-and-plate electrostatic precipitator for which the fundamental collection processes were descrihed in the class.
In general, feedback from spring 1985 indicated that the Dace of the course should he slowed and that fewer suhiects ihould he covered in greater depth. In particular, more time was suaaested for material and enerev balances and pollution cozn)l. Onesuggestion was totaki a renl plant prnhlem asacommon thread and follow it through thecourse. Also, in the future, the focus of the organic chemistry classes will shift toward both industrial chemistry and more applied organic chemistry problems that are integrated with the rest of the curriculum. Perhaps another plant trip will he arranged. Finally, rather than a standard final exam covering the course material (as has been past practice), in the future (as su~eestedhv one of the ~articioants)we will instead have takLLome exam that wilirequire the participants todevelop a lesson plan reflecting what they learned in the course.
Process and Plant Design In the chemical engineering curriculum, this is a seniorlevel course that is intended to bring together all of the principles learned earlier in order to synthesize a (relatively) complete plant design. At NJIT, there are very few lectures 318
Journal of Chemical Education
Plant Visit
a
T h e unanimous feeling of all past participants was t h a t the course was a very interesting and useful introduction t o a n engineering discipline. Although not specifically intended, it also provided much-needed group therapy sessions for some dedicated high school science teachers, who had a chance t o talk t o their peers and t o see t h a t their efforts a t the high school level are indeed crucial t o the training of the next generation of engineers.
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Total Egg Balance: 120 eggslmin = 70 eggslmin Y. Therefore: Y = 50 (Large) eggslmin. Broken Egg Balance: 0.30 X 120 eggslmin = 25 eggslmin Therefore: W = 11(Large, broken) eggslmin. 25/70 = 0.36
(fraction of X-Large eggs broken with OldFred's left hand)
11150 = 0.22
(fraction of Large eggs broken with Old Fred's right hand)
Acknowledgment T h e authors would like t o thank the New Jersey Department of Higher Education, t h e New Jersey Institute of Technology, the Center for Pre-College Programs a t NJIT, t h e Chemical Industry for Minorities in Engineering (ChIME), and the DOW Chemical Company for their generous support of this program.
Appendlx 1. Materlal Balance Problem #1 ( 10) Eggs are sorted into two sizes (large and extra large) at the CheerfulChickenDairy. Unfortunately, business hasnot heengoodlately, and ever since the Cheerful Chicken's 40-year-old egg-sorting machine finally gave up the ghost, there have been no funds availableto replace it. Instead, Old Fred, one of the firm'ssharper eyed employees, has been equipped with a "Large" rubber stamp in his right hand and an "X-Large" stamp in his left and is assigned to stamp each egg with the appropriate label as it goes by on the conveyor belt. Down the line, another employee puts the eggs into one of two hoppers, each egg according to its stamp. The system works reasonably well, all things considered, except that Old Fred has a heavy hand and on the average breaks 30% of the 120 eggs that pass by him each minute. At the same time, a cheek of the "X-Large" stream reveal8 a flow rate of 70 eggslmin, of which 25 eggslmin are broken. Draw and label a flow chart for this process. (b) Write and solve balances about the egg sorter on total eggs and broken eggs. (c) How many "Large" eggs leave the plant each minute? (d) What fraction of the "Large" eggs are broken?
Appendlx 2. Material Balance Problem #2 ( 10) One thousand kilograms per hour of a mixture containing equal parts by mass of benzene and toluene are distilled. The overhead product stream contains 95% benzene, and the flow rate of the bottom stream is 512 kgh. (a) Draw and Label a flow chart of the process. (b) Calculate the flow rates of benzeneand toluene in the bottom stream. (c) What is the mass fraction of benzene in the bottom stream?
Solufion
512 k g h
(Xb = mass fraction benzene)
(a)
Solution
I 120 eggslmin (which pass by Old Fred)
sorter 70 X-large
eggslmin (of which 25 eggslmin are broken) T
1
Y Large eggslmin (of which Ware broken)
+ W.
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Total Material Balance: 1000 k g h = D 512 kgh. Therefore: D = 488 kgh. Benzene Balance: 0.50 X 1000 k g h = 0.95 X D Xb X 512 kgh. 500 k g h = 0.95 X 488 kglh Xb X 512 kgh. Therefore: Xb = 0.071 (or 7.1 w t % benzene in the bottom stream).
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1. Chem. EM. Nelus. 1980, (October 20),67. 2. NJIT Placement Office, 1982. 3. Chem. Eng. NPWB.1982,(October 18).49. 4. N Y nrnss, 198I.(October 11). 5. College Placement Council Salary Survey, July 1985. 6. he Rent a1 ~ o eta u PI. 1981,(summerissue). 7. Chom. Eng.Neiur, 1982, (October 18),48. 8. Chom. Eng. N e m . 1985,(Odober 281.44. 9. Chem. En& Pmg., 1985,(July), 19. 10. Felder, R. M.: Rousseau, R.W. Elementary Principlar of Chemical Rocersas: Wiley:
New York,1978. McCrsw-HiU: New York, 1982. 11. Prob~tein,R. F.; Hieka, R. E. Synfhalc~els;
Volume 64
Number 4
April 1987
319
