CHEMICAL ENGINEERING AS A PROFESSION* JOHNC OLSEN.THE POLYTECHNIC INSTITUTE, BROOELYN. NEWYORE
The field of the chemical engineer, which i s distinct from that of the chemist and the mechanical engineer, is first discussed. Twenty-five to thirty years ago this distinction was not recognized. There has been such a great advance in the special knowledge and literature of chemistry and chemical engineering and also in mechanical engineering that i t is no longer possible for a single man to combine these twofields. The work of the chemical engineer i s to develop commercial processes, design the equi@ent, superintend the installation and the operation of industries manufacturing chemical products. I n order to do the work in this field the profession of chemical engineering has been developed. The engineering schools and universities which have offered specialized courses in this branch of engineering have today an enrolment of about 5000 chemical engineer in^ studen& with a n aggregate annual graduating class of not far from 1000. The American Institute of Chemical Engineers was organized twenty-three years ago to foster the public and professional relations of the chemical engineer and encourage the publication qf chemical engineering literature. This organization now numbers nearly a thousand members and i s growing rapidly. The literature of chemical engineering has been developed at a n euer-increasing rate during this period. The well-educated chemical engineer who understands the ,fundamental operations in this branch of engineering i s now able to take positins of responsibility in any of the numerous chemical industries. This arises from the fact that chemical engineering processes have been analyzed and found to consist of a number of typical and .fundamental unit operations which are employed in their proper sequence in all chemical industries. The magnitude of the chemical engineering industries i s indicated by the fact that the total output in 1929 had a value of eleven billion dollars representing approximately one-fifth of all manufacturing industries in the U. S. The petroleum industry i s the largest single employer of chemical engineers, having taken 15 per cent of the chemical engineering graduates in 1929. The chemical engineer i s concerned with technical research and production and economic aspects of the chemical industries. Many of the higher executives in these industries are technically educated chemical engineers. The compensation received by chemical engineers i s comparable with thal received by engineers in other fields doing work of corresponding importance or occupying positions of equal responsibility. The initial annual salary of the young man graduating from the usual four-year course will be from $1500 to $1800. The graduate with a master's degree will receive a somewhat larger compensation ranging from $ZOW to $2400, while the man having a doctor's degree will receive from $2400 to P.7000. I n frwn five to seven years this compensation i s usually doubled. Delivered before the students' course in Elementary Chemical Engineering held at the 13th Exposition of Chemical Industries. New York City. May. 1931.
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Many problems still await solution. The loss in the petroleum industry f r m corrosion alone i s $125,000,000 annually. A billion gallons of gasoline i s lost every year by evaporation. A n excellent dlustration of the important senice of the chemical engineer isfound in the wood distillation industry which was seriously threatened by the production and marketing of synthetic methanol and acetic acid. B y applying modern chemical engineering methods' the yield and purity of the products of the wood distillation industry were so i m prmed and the methods so modernized that this industry was saved. Many other technical processes needing improvement and moderniwtion await the semice of the chemical engineer. Only those industries whose managements realize this fact and avail themselves of the semices of the chemical engineer will long survive modern competitive business conditions. Before discussing the professional aspects of my subject it will he necessary to define the field of the chemical engineer. As the name implies, only those operations which are based upon chemical reactions would be included in the work of the chemical engineer. By no means can all such operations be classified as chemical engineering. The man who operates the chemical engine of a fire department cannot be designated a chemical engineer even though the fire-extinguishing liquid which he uses results from a chemical reaction. The reason for this is that this fireman does not need to know even the most elementary chemical principles in order to be an efficientfireman. On the other hand, the man who invented this method of extinguishing a fire and designed the machine which utilizes chemical reactions for this purpose might properly be classified as a chemical engineer. Such a man must understand not only fundamental chemical principles but also the mechanical principles involved in the design of the apparatus in which the chemical reaction will take place. In this case i t is absolutely essential that the chemical reaction shall be under such control that it may start instantly, progress a t a predetermined rate, producing a definite product, while it is equally essential that the reaction shall not take place until the instant when the apparatus is needed to extinguish a fire. Even a few seconds' delay a t this critical moment may mean the loss of a great deal of valuable property. It is the combination of just this kind of rigid control of chemical reactions together with mechanical skill which constitutes the work of the chemical engineer. It should of course not be overlooked that the chemist first worked out the reaction between the bicarbonate of soda and acid, or aluminum sulfate, which is utilized in the acid and soda, or foam extinguisher. The design of the apparatus which makes use of these reactions for extinguishing a fire is the work of a chemical engineer.
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Twenty-five or thirty years ago it was considered that the man who was chemically trained and had native mechanical ability, or the mechanically trained man who had an elementary knowledge of chemistry could satisfactorily do the work of the chemical engineer. At that time the then president of the Massachusetts Institute of Technology expressed the opinion that a chemical engineer was a mechanical engineer who had an acquaintance with chemistry. Since that time the science of chemistry, particularly theoretical and physical chemistry, has made such enormous strides that it is beginning to become questionable whether the graduate of a fouryear course in chemistry from one of our best educational institutions has acquired a sufficient grasp of the fundamentals of chemistry to be able to read intelligently modem chemical literature. The principles covering the control on an industrial scale of even very simple chemical reactions have been very highly developed. The industrial research chemist has very often spent three or more years after his college course in study and investigation in one of our universities before he is competent to devise or improve a modem industrial chemical process. Similarly very great advances have been made in the production of power and the design of mechanical equipment which is the special field of the mechanical engineer. It has therefore been found necessary to educate and develop a type of engineer who has specialized in the design of apparatus and the control of operations which are fundamentally chemical. This field of the chemical engineer has been found sufficiently well defined and specialized to constitute the basis for a new branch of engineering. The engineering schools and universities have offered specialized courses for this branch of engineering so that today there are about 5000 chemical engineering students in our American institutions with an aggregate annual graduating class of nearly 1000. Twenty-three years ago the American Institute of Chemical Engineers was organized as a professional society to foster the public and professional relations of the chemical engineer and encourage the publication of chemical engineering literature. This organization now numbers nearly 1000 members and is growing rapidly. Chemical engineering literature has also developed a t an ever-increasing rate during this period. There are now available some thirty volumes of the Transactions of the American Institute of Chemical Engineers as well as seven most excellent volumes of the British Institution of Chemical Engineers, a large number of most excellent monographs and textbooks, as well as several periodicals such as Chemical & Metallurgical engineer in^ and Industrial & Engineering Chemistry of the American Chemical Society, devoted almost exclusively to the current literature of chemical engineering. The current literature of chemistry and chemical engineering has become so voluminous that many members of
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the American Chemical Society interested in pure chemistry can find time to read only the periodicals in this field, while other members interested in chemical engineering read only the industrial journal. Specialization is rapidly becoming inevitable on account of the limitations of time alone. In spite of this situation, the special field of chemical engineering is by no means generally recognized. The organized body of chemists has not conceded that the chemical engineer is anything more than a special kind of chemist, while the mechanical engineer often contends that he has ample knowledge of chemistry to design and operate chemical engineering equipment. With the rapidly increasing specialized knowledge of both chemistry and engineering as well as the arrival of a large body of younger welltrained chemical engineers both of these points of view will gradually disappear. The recognition of chemical engineering as a separate branch of engineering has been greatly accelerated by the recognition that every chemicalengineering process consists of a number of well-defined unit operations which in their proper sequence constitute a complete process. The man who has a proper understanding of these unit operations may successfully serve industries whose fundamental operations are very different chemically. This is well illustrated by the records of a group of ten chemical engineers reported by H. C. Pamelee (I). Employment Records of Ten Typical Chemical Engineers in Industry succersive Positions Held
Indvsny in Which EmDlWed
1 Ass't Supt. Chemist Superintendent Works Manager Superintendent 2 Research Chemist Superintendent Superintendent Ass't Supt. 3 College Professor Chemical Engineer Superintendent Vice President 4 Chemical Engineer Engineer of Design Chemical Engineer Chemical Engineer Plant Engineer Consulting Engineer 5 Foreman Superintendent
Water Gas Paint and Varnish Dyeworks Electpxhemicals Fine Chemicals By-product Coke Metal Refining Lithopone Mfg. High Explosives Organic Chemistry Indigo Manufacture Coal-Tar Chemicals Dye Manufacture Leather Tanning Equipment Mfg. Fine Chemicals Asphalt Fine Chemicals Chem. Engineering Electroehemicals Coal-Tar Products
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Induslry
in Which Emplorcd
6
7
8
9
10
Ass't Supt. Superintendent Plant Engineer Chemist Foreman Superintendent Superintendent Superintendent Plant Manager Chemical Engineer Chemical Engineer Superintendent Plant Engineer Chemical Engineer Research Chemist Chemical Engineer Chemical Engineer Superintendent Construction Engr. Plant Engineer Wood Paving Inspector Development Engr. Chemical Engineer President Superintendent Operator Chemist Sales Engineer Superintendent
Synthetic Phenol Explosives Fine Chemicals Electrochemicals Iron and Steel Sulfuric Acid Explosives Caustic Soda Pyroxylin Lacquers Matches Dyeworks Sulfur Chloride Electrochemicals Rubber By-product Coke Pulp and Paper Fine Chemicals Dyeworks Poison Gas Plant Fine Chemicals New England City Coal-Tar Products Pharmaceuticals Consulting Engineers Dyeworks Coated Paper Iron and Steel Equipment Mfg. Beet Sugar Plant
It will be noted from this table that the man doing chemical engineering work is not always designated as a chemical engineer but that he often holds positions such as superintendent, plant manager, vice president, etc. The industries which he serves cover the entire range of chemical industries. Only in the case of number three are the industries in the same general division of chemical industries, namely, dye manufacture. The well-trained chemical engineer is evidently no longer limited to a single basic chemical industry as was often true in the past. The unit operations as commonly recognized are as follows: Evaporation Distillation Mixing and Agitation Heat Transfer Materials Handling Filtration
Drying Absorption and Adsorption Crushing and Grinding Flow of Fluids Crystallization Classifying and Screening
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A study of any one of the following very diversified chemical industries will show that the processes employed are merely aggregates in proper sequence of the unit operations listed: Heavy Chemicals Electrochemicals Explosives Petroleum Refining Sugar Refining Cement and Lime Fertilizer Rubber Gas ~ a n i f a c t u r e Ceramics Leather
Fine Chemicals Dyes and Coal-Tar Products Coal Processing Wood Distillation Pulp and Paper soap Paint and Varnish Glass Vegetable Oils Textiles and Rayon
For instance, in sugar refining the raw sugar is dissolved in water and the impurities are precipitated out by means of lime and phosphoric acid. The precipitate is removed by means of a suitable filter press. The sirup is decolorized by adsorption with bone black. The clarified sirup is then evaporated in vacuo until the sugar crystallizes out. The sugar is separated from the remaining sirup by means of centrifugal machines and
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washed. After drying the sugar is ready for the market. In this industry the following unit operations in the following order have been employed: filtration, adsorption, evaporation, crystallization, drying. Heat transfer, materials of handling, and flow of fluids have also been applied in carrying out these operations. In a similar manner the other processes listed may he shown to be aggregates of unit operations in proper sequence. The magnitude of these industries is indicated by the fact that their total output in 1929 was $11,000,000,000, representing approximately a fifth of all manufacturing industry in this country. While the technical
control of these industries must be in the hands of the chemical engineer because the fundamental reactions are chemical, other technical men must be employed and cooperate in their special fields such as the chemist, mechanical, and electrical engineer, etc. I t will be noted from Table I that there are a total of 16,579 chemical establishments in the United States employing a total of 1,099,577 wage earners. It is rather surprising to note that the three industries having an output of more than a million dollars worth of products are in the order of size, petroleum refining, rubber goods, and paper and pulp. While the cost of materials is $6,299,463,068, the value added by manufacture is
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$4,548,789,786. This increase in value is a product of the work of the chemist and chemical engineer. It will be noted from Table 11 that the greatest concentration of chemical industries is found in New York State and Ohio, with Pennsylvania, New Jersey, and Illinois coming next, followed by Michigan, Texas, Louisiana, and California. The remaining unmarked states on the map have relatively few chemical industries. Table 111 shows very clearly that the most diversified chemical industries use the same standard equipment. It is this uniformity of processes carried
I
The Process Industries Market for Equipment
out which enables the well-trained chemical engineer to serve with equal success any one of the various industries listed. This condition gives unity to the chemical engineering profession. It is interesting to note that in recent years the petroleum refining industry has been the largest single employer of chemical engineering graduates. A study made by James A. Lee (2) showed that 15 per cent of the 741 graduates in chemical engineering in 1929 entered the petroleum industry. Heavy chemicals, explosives, pulp and paper, sugar refining, soap, ceramics, and glass each took 5 per cent or more of the total.
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I t should also be noted that the wood distillation industry employed the smallest proportion. While the petroleum industry has been one of the most prosperous, the wood distillation industry has been threatened with extinction on account of the competition by the products of other more technical industries. The chemical engineer's principal contribution in each of these fields of industry is in production. He may design and construct a plant but most of his time is devoted to operation. Therefore a great many of the chemical engineers in industry today have titles of supervisors, department heads, plant superintendents, production managers, etc. There was a time when the chemical engineer's only entrance to the production organization was through the laboratory. Today many, if not most, men enter as c a d e t engineers, shift supervisors, assistant foremen, and the like. There is no royal road to success for the chemical engineer, but because the production man "makes the wheels go round," he becomes a most essential part of industry and his opportunity for advance' ~ ' A ~ L IV E ment to executive responsibility is correspondingly large. The work of the chemical engineer in developing processes is of very great importance. In many of the larger and more integrated industrial organizations, there is a distinct division of work between the research chemist on the one hand and the research engineer and development man on the other. The chemist commonly conceives the process and demonstrates it on the laboratory scale. The chemical engineer takes the labora-
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tory process, proves and develops i t first in the semi-works, then in the full-scale unit, and finally in the commercial plant. In smaller organizations, chemical engineers are often selected for chemical as well as engineering research. This is primarily because of the flexibility that makes the chemical engineer adaptable to the solution of both chemical and engineering problems. The opportunity for the chemical engineer in technical research is second only to that in production. His rise may be equally as rapid, despite the fact that research, unfortunately, is not universally recognized as an indispensable department of all industry. And not until research is planned on a long-term basis, with a d e f i ~ t financial e reserve set up to take care of it, will the research organization have the same security and stability that is found in production work. Another very important part of the work of the chemical engineer is in the field of economics. Just as industry succeeds only as it makes a profit, so the chemical engineer is vitally concerned with the economic bases of industrial operations. Before a process from the research laboratory can be translated into successful commercial production, some one must carefully study its economic feasibility-its primary utility as compared with existing processes and practices. This gives rise to a great and growing opportunity for the chemical engineer. Likewise the same methods are applied to the study of industries themselves-by chemical engineering advisors for investment trusts, banking houses, etc. Because the market for the product of a chemical engineering process determines its success or failure, the chemical engineer is often called upon to study chemical (as contrasted with chemical engineering) economics. He must know the methods and principles of market analysis, costs and prices, studies tariff and freight rates, and many other factors that in their aggregate have come to be known as the field of commercial research. This field is relatively new hut it is growing rapidly, especially as the business depression has put a premium on the more scientific aspects of industrial marketing. These opportunities for the chemical engineer in industry all lead eventually into executive work for the man who is willing to take over the responsibilities of direction and supervision. And because the engineer has been trained to get his facts and base his conclusions and action on such data, rather than on guess-work or hunches, he is most often successful, particularly in a technical enterprise. We must not forget, too, that these process industries, with their constantly changing technology, require a better appreciation of the intimate technical detail and possibilities of the job and of the industry as a whole. Hence the increasing number oi socalled "technical executives." A limited number of chemical engineers must be engaged in teaching this
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subject in the institutions which offer courses in this subject. As chemical engineering requires a knowledge of both scientific principles and plant practice i t is essential that the men who teach this subject should have had a number of years of practical experience in plant design or operation before undertaking the teaching of this subject. Most professors of chemical engineering also have the opportunity of practicing their profession as consultants in some branch of chemical engineering. This work serves to keep the professor abreast of the most recent progress in the subject which he teaches and also serves as a very desirable supplement to his academic salary which is not always adequate. However, the eminently practical character of chemical engineering education calls for high-grade men, and in most institutions, salaries are correspondingly high. The university laboratories offer further attraction for chemical engineers to carry on research and development either independently or with the cooperation of an industry. Certainly the man interested in chemical engineering as a career does not want to pass up these opportunities without a careful consideration of the intangible as well as the tangible values in teaching. The compensation received by the chemical engineer is comparable with that received by engineers in other fields doing work of corresponding importance or occupying positions of equal responsibility. The initial annual salary of the young man graduating from the usual four-year course will be from $1500 to $1800. The graduate with a master's degree will receive a somewhat larger compensation ranging from $2000 to $2400, while the man having a doctor's degree will receive from $2400 to $3000. In from five to seven years this compensation is usually doubled. Under normal business conditions i t is frequently possible for the young chemical engineer to choose the industry in which he prefers to work. In spite of the high state of efficiency to which many of the chemical industries have been brought, most of them still offer many opportunities for further development and improvement by the chemical engineer. Even the petroleum industry which has recently absorbed so many chemical engineers has many problems for which an early solution is demanded. It may he of interest to list some of them. The Corrosion Committee of the American Petroleum Institute reported that the evidence obtainable indicated that the annual loss to the petroleum industry from corrosion alone, in the field, pipe line, storage, refining, and marketing reaches the enormous figure of $125,000,000 annually. It is undoubtedly possible to reduce this loss materially. The estimated fire loss to the industry was $1044 per minute in 1925. The aggregate of this loss is much greater than that from corrosion, the prevention of which offers a very promising field for the chemical engineer. A billion gallons of gasoline is lost every year by evaporation in handling and storing this volatile product. This loss starts as soon as the petroleum
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is pumped out of the wells and continues during the manufacturing process, storage, and transportation of the gasoline. The evaporation loss has been reduced by a number of improvements in the industry. These include the selection of the most suitable paint for the storage tanks as well as floating roofs for these tanks. The most revolutionary process introduced into the petroleum industry has been the Bergius hydrogenation process by which heavy oils and residues may be converted into more valuable lubricating oils and gasoline. By means of this process it is possible to convert 100 per cent of the petroleum into valuable products, it being also possible to produce any desired proportion of any given product. This gives the industry a flexibility which it has lacked in th: past. This process is a t present in the development stage and requires much technical work for its installation, adaptation, and operation. The magnitude of the industry is indicated by the fact that in 1926 12,500,000,000 gallons of gasoline were used. The tremendous waste of our natural resources is indicated by the fact that in the operation of an automobile only 5 per cent of the energy of the gasoline is actually utilized in pushing the automobile. Here is a most fertile field for research and improvement by the chemical engineer. I have mentioned only the larger research problems awaiting solution in this industry. The highly complicated processes which are being installed in this industry will always require a well-trained staff of operating engineers among whom the chemical engineer will always have a prominent place. The rule holds trne for all chemical industries that active research development will always call for a corresponding complement of welltrained operating staff. Another industry which illustrates the Importance of the service which the chemical engineer may render is that of wood distillation. This industry is relatively old, the methods first used having been very primitive. While improvements were gradually introduced, progress was not as rapid as in many other industries. This was partly due to the fact that the plants were scattered and generally relatively small so that any single plant was not able to bear the expense of extensive research and development. In addition to charcoal, the most important products were calcium acetate and methyl alcohol. The most important use for calcium acetate was the production of acetic acid. Within recent years synthetic methods for the production of acetic acid and methyl alcohol a t very low cost have been developed. As this threatened the existence of the wood distillation industry, it was necessary to modernize the processes used and reduce the cost of manufacture of the products in order to save the industry. When called in for this purpose the chemical engineer found many features of the processes which could be greatly improved. The first
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operation which the wood distiller carries out is the removal of about half of the moisture content of the green wood. The recently felled wood contains from 40 to 50 per cent of moisture which must be reduced to 20 to 25 per cent. The method formerly employed for this purpose was to allow the wood to remain in the open air until dry. This required from twelve to eighteen months. It was therefore necessary for the wood distiller to carry on hand a t all times from one year to eighteen months' supply of wood. When the chemical engineer had modernized this process the wood was dried in a tunnel drier using waste heat, the green wood being fully dried within forty-eight hours. As the dried wood passes directly from the drier to the retorts it enters the retorts already heated to the temperature of the drier. This was found to be of considerable advantage in the carbonizing process. The temperature of the retorts is carefully controlled so that the best conditions for carbonizing are always maintained. This gives the highest yield of valuable products. It was found possible to improve greatly the distillation process for the separation of the alcohol and acetic acid so that a higher yield and a purer product was obtained. The necessary evaporation is now carried out in multiple effect evaporators using exhaust steam. It has also been found possible to extract acetic acid direct from the pyroligneous acid and even to produce glacial acetic acid by this process. As a result of these and other imorovements it has been ~ossiblefor the chemical engineer to rescue an industry from extinction. Many other technical processes needing improvement and modernization await the services of the chemical engineer. Only those industries whose managements realize this fact and avail themselves of the services of the chemical engineer will long survive modem competitive business conditions. Literature Cited PARMELEE, Cham. 8 Met. Eng., 35 (Jan.,1928). (2) LEE, ihid., 36,4 1 M (July. 1929). (1)
