CHEMICAL ENGINEERING DESIGN COURSES-A SURVEY' FRANK H. CONRAD
AND
W. E. YATES
Missouri School of Mines and Metallurgy, Rolla, Missouri
It has been known for some time that wide differences of opinion exist as to the place of chemical engineering design in a n undergraduate four-year curriculum. B y the questionnaire method, a survey of the chemical engineering courses of approximately forty colleges and of a n "ideal" chemia.1 engineering design course as outlined by forty different industrial companies has been made and the results tabulated. The results show that there i s a definite demand for such a course i n a four-year chemical engineering curriculum. Many of the differences of opinion would perhaps disappear if the term "design" were redefined. The authors
I
look upon such a course as one which will integrate or correlate the student's prm'uus work in the more fnndamental courses. A more descriptive title should be given such a course than the present names of Plant Design m Equipment Design. Replies on the questionnaires indicate that some title such as "Chemical Plant Equipment and Layout" or "Process Design and Equipment Selection," or "Process Design, Equipment Selection, and Plant Layout" would be more descriptive of the courses as they are now taught. Such titles would serve to clarify a situation which has arisen from the broad dejhition of the word "design."
T HAS been known for some time that wide differ- engineering design courses was to obtain information ences of opinion exist as to the place of chemical from both the educational and the industrial fields as engineering design in an undergraduate four-year to the place of such a course in the four-year chemical curriculum. Some colleges have offered a course in engineering curriculum. plant design, some a course in equipment design, some Questionnaires qrere sent to thirt$'schools which have have offered both, and some have not offered any had their chemical engineering courses placed on the separate course in design. A portion of this last group accredited list by the American Institute of Chemical have felt that a four-year period was too short to Engineers, and to eleven non-accredited institutions cover adequately the more fundamental subjects of offering a B.S. degree in chemical engineering. The the curriculum, and hence, have not allotted time to the percentage of replies received from the accredited more professional subject of design: Certain others schools was 83.4, whereas only 72.7 per'tent. of the nonhave felt that su5icient design was already being accredited group returned their blanks. A total of taught in the unit operations course. Referring to the 80.5 per cent. of all questionnaires sent to educational 6rst edition of the text, "Principles of Chemical Engi- institutions was returned. neering" by Walker, Lewis, and McAdams, in a paper It was felt that a complete picture of what a design entitled, "Development of Chemical Engineering Edu- course should be could not be *awn without consideracation in the United States,"l Newman3 states, "This tion of the industries which employ men trained in book was a textbook of the 'Unit Operations' and dealt chemical engineering. Accordingly, forty-three comwith the rational quantitative design of chemical engi- panies were asked to express their opinions. Because neering equipment." The fact that this text does deal the number of industries was small compared with the with quantitative design, perhaps explains why some total number in the United States, they were selected chemical engineering departments have felt that they with care so as to be nearly as representative of the were giving sufficient design. whole chemical industry as possible. Tbey consisted The primary purpose of this survey of chemical of manufacturers of heavy chemicals, process industries, petroleum refineries, equipment manufacturers, 'Presented before the Chemical Engineering Division of the Missouri Section of the Society for the Promotion of Engineering solvent producers, steel companies, and, in one case, a Education, Spring, 1939. Presented at the Summer School for consulting chemical engineer. Tbey were distributed Chemical Engineering Teachers. Pennsylvania State College, thoughout the country but were more heavily T..-,010 ~ W A L K ~ K ,L E ~ SAm , M~ADAMS, -principles of chemical concentrated in the large manufacturing centers. engineering," 1st ed., McGraw-Hill Book Co., Inc.. New York Replies were received from 74.4 per cent. of the comCity, 1923, 749 pp. 3 NEWAN, TI(IIZS. Am. I S S ~ .them. E ~ ~ , S 34, . , NO. 3a sup- panics, but only 65.1 per cent. filled out the questionplement (1938). naires. 85
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A"u".
WHAT
IS
CHEMICAL
ENGINEERING
DESIGN?
Perhaps one of the most outstanding facts brought out by the comments included on the returned questionnaires was that there is considerable variation in what is termed "design." It was also obvious that as long as the courses of various colleges continue as outlined on the returned questionnaires, there is little danger of them becoming standardized to the detriment of the profession. Instructors will naturally emphasize those subjects with which experience has made them most familiar. Various definitions of design are to be found in the dictionaries. Webster states that design is the "purposive planning as revealed in, or inferred from, the adaption of means to an end or the relation of the parts to the whole." Such an all-inclusive meaniuz of the term "design" was observed by the replies received, both from the educational institutions and industrial concerns. The fact that a largemajority of the replies indicated that desien courses were chieiiv used in the determination of &e. and the selection of standard and leads to the logical clusion that design, from the creative standpoint of somethinp new 1s perhaps a misnomer and that a more descrlotwe title should be used. The authors look uoon such a course as one which integrates or correlates a student's former work in chemistry, unit operations, mathematics, physics, and mechanics. In -short, it should tie together four years of undergraduate study in such a way that the student may be able to see the forest instead of merely the trees. A further study of comments on the questionnaires showed that there is considerable overlapping in the topics taught in plant and equipment design. The tabulated data from both the educational institutions and the industrial concerns are shown in Table 1. The authors selected only tliose topics which were known to be taught by some design ipstructors in compiling the list of subjects which might be covered under items seven and ten of the questionnaires. That this list was not complete is shown by the two following lists made up from the comments or additions by the individuals filling out the forms. Approximately onehalf of each of these lists was suggested by the colleges, and the other half by the industrial concerns. No conclusions can be drawn as to the relative importance of any of the items mentioned. On the other hand i t should be stated that many of them appeared on several different questionnaires. ADDITIONAL TOPICS
(POSSIBLE)FOR INCLUSION PLANT DESIGN
WITH
(Question 7, Table 1) (a) (b) (c) (d)
Market study. Raw material study. Office space, lavatories, showers, space and equipment for , employees comrarr. Study available transportation facilities, railroad spurs. trucking, and so forth.
. .
.
(e)
Allowance of facilities for plant growth and flexibility.
(j) Required specials (special problems resulting from general
problems). Consider materials for construction from practicability, corrosion, and erosion standpoint. (h) Heat and weight balances. (9 Waste disposal. (j) Control instruments including automatic meters and how they should be included in the original design. (k) Water supply. (1) Process steam. (m) Work simplification through plant and equipment layout. (n) Maintenance. (a) Safety work and accident prevention. (9) Applications of heat and power. Waste heat recovery. Presentation of specifications to manufacturers and snaly(g) sis of manufacturer's proposals. (g)
ADDITIONAL TOPICS
(POSSIBLE)
INCLUSION 'WITH
-,..7.....-.,..--.-.ny "nJlun "lrLnnn 1
(Question 10, Table 1) (a) Efficiencies one may expect from various equipment. ( b ) High pressure equipment (mentioned by a number of industries). (c) Continuous proportioning devices. ( d ) Reaction vessels such as sulfonators and nitrators Gas-making equipment. (6) (j) Plast~crsuwmrnt ( 1 K'f"~a"un Pqu'~'en' ( h ) Agitation. (i) V,,,m equipment, jet condensers A STUDY OF TABULATED ANSWERS
It is interesting to note that a larger percentage of the industrial concerns than universities believe that a design course should be inc1ude.d in a four-year chemical engineerirrg curriculum:. Approximately one-third of the colleges replying have no separate design course, and approximately one-fifth believe that no separate course in design is advisable in the four-year curriculum. Certain replies might have been influenced by the fact that many of the colleges teach.unit operations in the senior year; consequently the students are not prepared for a general design course. Eighty-nine per cent. of the industries replying believe that such a course should be given. The replies from industry indicate approximately one more semester credit hour should be devoted to design than the colleges believe should be given. The time which the industrial replies indicate should be devoted to design is two semester hours greater than the average actually offered by the "average" college giving a course in design. It must be remembered, however, that the men from industry have not been up against the problem of arranging curricula in most Cases. No definite conclusions can be drawn as to how the time devoted to design should be distributed between plant and equipment, except, perhaps, that both should be offered in approximately equal amounts. The results shown in Table 1for question three do show a slizht balance in favor of equi~mentby both the cO1l:ges and the industries. wouid perhaps indtcate that more time should be devoted to equip-
TABLE 1
Industries Number of replie considered Question 1 to colleges only 0
Co2leges
Questions Number of replies considered
Number
Time devoted to design in a four-vear Chemkal En~ineer" ing course Semester hours (average credit) per four-year course I n your opinion, should time be devoted to a design course in a four-year undergrndunte rurrirulunt in rhtn~icalcneineering? If so, how mu&? Semester hours (credit) per four-year course I n your opinion, should more emphasis he olaced on olant design or eq&pment design? Indicate percentage of each What text is used? (Some indicated more than one text)
Is (should)* an attempt (be)" made t o include cost investigation along with design? Are (should) the following topics (be) included in the chemical eneineerine desien course? ( a ) ~ri&iples01pla& location
b ) By discussion (6) By actual problem
30.3 per cent. (10) No course 6 9 . 7 per cent. (23) Have course 3 . 1 8 hours Yes 7 2 . 7 per cent. (24) No 18.2 per cent. ( 6 ) No answer 9 . 1 per cent. ( 3 ) 3 . 9 4 hours
Average use of time in plant design 47.7 per cent., equipment design 5 2 . 3 per cent.
12 Vilbrandt Perry 5 Literature 4 Experience 9 Walker, Lewis,el ol. 1 Badger and McCabe 1 Tyler 1 Plant Note-Book 1 Machine Design text 1 Yes 7 2 . 7 per cent. (24) N-none No answer 2 7 . 3 per cent. ( 9 )
in
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Average use of time Plant design 4 0 . 8 per cent. Equipment design 5 9 . 2 per cent. I n addition four favor plant design, two favor equipment design, one gave no answer Question 4 t o colleges only
Yes 7 8 . 6 p e r cent. (22) No 1 4 . 3 per cent. ( 4 ) No answer 7 . 1 per cent. ( 2 )
Eight in both (b) and (c)
Yes 8 2 . 2 per eent. (23) No 7 . 1 per cent. ( 2 ) No answer 10.7 Der cent. 131, kes 8 2 . 0 psr ceit. Yes 2 6 . 1 per cent. Per cent. of those answering yes to (a) Two m both (b) and (c)
Yes 3 4 . 6 per cent. ( 9 ) Yes 57.7 per cent. (15) Yes 34.6 ner cent. ( 9 ) Yes 2 6 . 9 ber cent. i7i Y e s 34.6 per cent. ( 9 ) Yes 4 2 . 3 per cent. (11) Yes 4 6 . 2 per cent. (12)
Yes 5 3 . 3 per cent. Yes 53.3 per cent. Yes 6 6 . 6 per cent. Yes 6 0 . 0 per rent. Yes 56.7 per cent. Yes 6 6 . 6 per cent. Yes 56.7 per cent.
(16) (16) (20) (18) (17) (20) (17)
Yes 100 per cent. Yes 8 0 . 8 per cent. Yes 7 6 . 9 per cent. Yes 9 6 . 1 per cent.
Yes 8 6 . 6 per cent. Yes 6 6 . 6 per cent. Yes 6 6 . 6 n u cent. YA 86.j per cent.
(26) (20) (20) (26j
Yes 7 2 . 7 per cent. (24) No 9 . l p& cent. ( 3 ) No answer 18.2 per cent. ( 6 ) Yes 7 5 . 0 Der cent. y e s 5 8 . 5 ber cent. Per cent. of those answering yes t o
(4
A complete plant including, (a) Foundations ( b ) Building (c) Drainage (d) e a t i n g (e) Llghtiug ( j ) Ventilation ( g ) Power transmission ( h ) Selection of standard process equipment ( i ) Con\ieying equipment Q Spec~alstorage facilities Selection of size, and the location of, pipe lines for process equipment (gas, water, steam, and so forth) Flow diagrams Design of profess equipment including. ( a ) Heat transfer equipment (b) Kilns and furnaces (6) Evaporators (d) Driers (e) Gas absorbers Extractors (g) Filters (h) Mixers
Yes 8 9 . 3 per cent. (25) No 10.7 per cent. ( 3 ) 4 . 8 5 hours
(26) (21) (20) (25)
.
Yes 9 6 . 1 per cent. (25)
Yes 9 6 . 6 per cent. (29)
Yes 7 6 . 9 per cent. Yes 4 6 . 2 per cent. Yes 5 7 . 7 per cent. Yes 5 7 . 7 per cent. Yes 6 5 . 4 per eent. Yes 3 8 . 5 per cent. Yes 5 7 . 7 per cent. Yes 23.1 per cent.
Yes 8 0 . 0 per cent. (24) Yes 7 0 . 0 per cent. (21)
(20) (12) (15) (15) (17 (10 (15) (6)
1
Yes 56.7 per cent. (17) Yes 6 3 . 3 per cent. (19) Yes 6 0 . 0 per cent. (18)
(*) Refers to questions to industries. (a) Of the thirty-three replies, seven gave no course and three gave no answers. However, since some schools giving no course covered part of the items listed in other courses, an average of twenty-six has been taken as a basis of replies for questions 7-12, inclusive. (b) Twenty-seven companies filled out the questionaire. One company sent six answen, making thirty-two answers considered in 7-12. inclusive.
Questions Number ( i ) Crushers Distillation equipment Air conditioning equipment
Number of replies conridered
ti) 11
12
If equipment design only would be given, should an attempt be made to cotirdinate the various pieces of unit operation equipment into a complete process
26(a)
Colleges
Yes 30.8 per cent. (8) Yes 6 1 . 5 per cent. (16) Yes 38.5 per cent. (10)
Number of replies consdidered 30(b)
Answers to question as stated on 30(b) questionnaire were unsatisfactory
ment. On the other hand, certain comments indicated the lack of a sharp line of distinction between plant and equipment design. A number of the individuals replying, however, feel quite strongly on the subject of plant design versus equipment design as indicated by the following quotations. "The design of unit operation equipment is basic to plant design and, therefore, should be stressed." "There are possibly a dozen good equipment designers in the country. There is little need for any more." "Only after years of experience will one enter plant design. Efficiency and speed i n representing one's ideas are major objects in design. I think one thorough design is better than much flow sheet and plant design." "The equipment design is only that portion which the nature of the plant design problem demands. The emphasis is on plant design." "Equipment is not beyond the young engineer's range of intelligence." "Although equipment design is very important, it is only in plant design that the proper correlation of a student's previous work can be accomplished to the best advantage." Table 1 shows a large proportio~of the industries in favor of the inclusion of almost every topic listed under questions seven and ten. The per cent. of the colleges in favor of inclusion of the various items runs three to thirty per cent. lower than that of the industries in favor of the same topics. This is entirely in accord with the additional time which the industries believe should be devoted to design. There are several exceptions to this generalization, however, namely questions 7b, 7h, and 7i,which are in the reverse order. The answer to 7h may, perhaps, be explained on the basis that some of the men from industry may not have considered the selection of standard process equipment as design. Comments indicated that a large majority of both groups believe that selection of standard equipment should be stressed. One question which should have been asked on the questionnaire is as follows. Is, or should, an attempt be made to correlate design with experimental process laboratory work? Dodge4 has indicated one method 4 DODGB. J. @!ax. EDUC., 15,479 (1938).
Industries
Yes 6 0 . 0 per cent. 18) Yes 76.7 per cent. d.3) Yes 46.7 per cent. (14) Stress 10.0 per cent. Briefly 30.0 per cent. For prccess 6 . 7 per cent Yes 90.0 per cent. (27)
by which this correlation between laboratory and design might be obtained. Vilbrandt' has suggested another method which is perhaps not so comprehensive as that of Dodge. A study of the catalogs and replies from the questionnaire revealed that only five of the forty-one schools receiving the questionnaire cany on this type of work a t present. Such correlation is worked out in this type of course by obtaining qnantitative data in tbe laboratory for the process under consideration. This is particularly true in cases in which data are lacking in the literature or are very meager. The data so obtained are then used in making the necessary calculations for the design either of a pilot plant or commercial plant. Undoubtedly, other schools make use of data obtained from routine laboratory work or from research in the design of some special equipment. Some of the collegiate questionnaires contained remarks indicating that their authors. believed poor economy of students'.time resulted.from such an attempted coordination. A review of the catalogs of the schools to which questionnaires were sent also showed that 14.6 per cent. of the number require one or more courses in machine design-in most cases in addition to the regular chemical engineering design. A STUDY OF REMARKS
Probably the most interesting part of the results of this survey was contained in the remarks and comments made on the returned questionnaires. In a paper of this type i t is imPossible to reproduce all of them, hence i t will be necessary to generalize and draw such conclusions as are possible. Table 1, while it contains certain qualitative information as to the content of a chemical engineering design course, shows very little as to the amount of time which should be devoted to a particular subject or as to how heavily i t should be stressed. While most of the items under question 7 are included in almost every plant design course, the answers indicated that various individuals put much more stress on some items than others. For example, some included no details regarding a building, others a cost estimate only, while others merely discuss the subject in lecture. Some ' VILBRANDT, I d . Eng. Ckem., 31,253 (1939).
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schools choose a broad general problem and then select by calculation each item involved in the particular problem or plant layout. Obviously i t would be impossible to include a complete design of many of the items of equipment mentioned under question 10. Some schools after assigning the broad general problem limit the work by selecting one or more of the items under question 10 for a complete or detailed design. This, again, brings up the question of the definition of "design." A comment taken from one of the questionnaires regarding the design of process equipment states the case very aptly. "If, by 'design' is meant the preparation of detaiis su5icient for fabricating purposes, I do not believe that any of the items herein mentioned can be treated satisfactorily. However, if 'design' refers to the determination of basic sizes and operating conditions, all of the subjects have merit. The relative importance depends upon the industry." This need for clarification of the term "design" is not entirely new for Professor Hougen in a written discussion of Dr. A. B. Newman's8 paper writes as follows: "Plant design. Repeatedly your report refers to the necessity of the chemical engineer to design plants. I limit the interpretation of plant design to the ability of selecting equipment, to laying out its arrangement and determining sizes, capacities, dimensions and materials of construction. Others extend the meaninp to include the design of structures, involved mechgnisms and complicat~dmachinery. Surely adequate preparation to perform the latter tasks cannot he included in a four-year curriculum. The latter skills involve more extensive training in mechanics, structures and machine design than can be granted. A few chemical engineers will become great designers of machines, but should not these duties be left chiefly to the mechanical and structural engineer? Your Committee should clarify this point." The writer of one industrial reply, who did not he-
lieve in offering a design course in an undergraduate curriculum, apparently interpreted the word "design" in the restricted sense, for he says, "It is our belief that in most industrial organizations i t is more essential for the chemical engineer to be able to recognize the limitations and advantages of processes and procedures and materials of construction, and to be able to devise improvements in them, than to be able to determine details of construction of buildings and equipment involved. If he is able to write an intelligent (and intelligible) set of design data, then mechanical and civil engineers who have specialized in the design of foundations, structures, and machines can carry out his ideas far more expertly than he could hope to do." In view of the foregoing comments, would i t not be more appropriate and descriptive to rename our present so-called design courses? Replies on the questionnaires indicate that some title such as "Chemical Plant Equipment and Layout," or "Process Design and Equipment Selection," or "Process Design, Equipment Selection, and Plant Layout" would be more descriptive of the courses as they are now taught. SUMMARY
The results of the present survey may be summarized under the following headings: (1) There is a definite place and need for a "design" course in the four-year chemical engineering curriculum. (2) The term "design" as it is now applied to chemical engineering design courses should be clarified. (3) A more descriptive title should be given such a course. ACKNOWLEDGMENT
The authors wish to express their appreciation to the large number of individuals and companies that responded to the questionnaire. The complete manner in which many of the replies were worded was indeed gratifying.
