What Is A Chemical Engineer

What is a Chemical Engineer? Irv Wiehe When someone asks you at a cocktail party what you do for a living. You probably have learned by now not to say, “I am a chemical engineer.” You have learned that such a response is akin to saying, “I have avian flu.” You would quickly find yourself alone in the middle of the room. Why are we chemical engineers so misunderstood? I have friends who have said that although they have absolutely no idea of what a chemical engineer does, they are certain that they have no interest in hearing such a description, especially from a chemical engineer. I have another friend, a business manager, that only after knowing him a couple of years that he confessed that he had a chemical engineering degree. It was like he confessed that he kicked the habit only after years of attending chemical engineers anonymous. Why if chemical engineers have no image, not a bad image but no image, we ended up becoming chemical engineers? For me mathematics and chemistry were my two favorite subjects in high school. I could not choose between them as a college major. Also, we were told that the USSR was out producing the USA in engineers. Therefore, by majoring in chemical engineering, I could combine my two favorite subjects and be patriotic to boot. However, on a visit to the University of Cincinnati while I was in high school, I was introduced to chemical engineering by being shown the Unit Operations Laboratory. I came close to switching my major on the spot! I guess my attraction to work on the small laboratory scale later convinced me to go to graduate school to prepare for a career in research. However, I did not see the Units Operations Laboratory again until I was a senior in college and well prepared for it. It was not an image that attracted a high school student to chemical engineering nor was it necessarily representative of the field. When I taught chemical engineering at the University of Rochester, we had trouble hanging onto undergraduate students. For one thing, high school counselors advised students to declare a major in chemical engineering to increase their chances to get accepted by the University and then switch majors before taking a class. Even the University advisers recommended freshmen to drop classes from the chemical engineering curriculum because it was too difficult and forced them into another major (usually pre-med). Since chemical engineering is the only engineering field that is both applied physics and chemistry, an awful lot of knowledge has to be crammed into the head of an undergraduate student. Thus, a chemical engineer has to be willing to accept and to survive the most challenging curriculum on campus. My daughter would say, “Chemical engineers are no fun.” Perhaps this is the reason that newly graduated chemical engineers command the highest starting salaries on campus. When one of my fellow seniors at the University of Cincinnati interviewed for a job, he was questioned why he was near the bottom of his graduating chemical engineering class. His response was that he was in the top third of his entering chemical engineering class. The other 2/3 of the entering class did not make it. He got the job. Nevertheless, at the University of Rochester when we got students into their first chemical engineering class as sophomores, we defined chemical engineers for them as those that apply chemistry, physics, mathematics and engineering principles, to take laboratory results and turn them

into economical processes for producing value added products. This has been updated by AIChE (see http://www.aiche.org/CareersEducation/QuickFacts/index.aspx ) to drop “physics” and “processes” and to add “biochemistry”, “conceptual ideas”, and “safe (including environmental) manner”. While these definitions are closer to reality because they include applied math and sciences, scale-up, and economics, they are not designed to attract students into the field. I was fortunate that at University of Cincinnati all engineering students were co-op students. I at least saw first-hand what chemical engineers did at my co-op company. This was another reason that I decided to go to graduate school. Of course, the bachelors degree in chemical engineering is one of the few undergraduate degrees that entitles one to operate immediately on a professional level. However, with my heart set on research, I needed a PhD. We all see TV shows and movies potray people in other occupations: medical doctors, nurses, lawyers, policemen, crime scene investigators, social workers, teachers, and occassionaly a chemist. Unlike these occupations, we do not suffer from incorrect images by TV and movies but by no image. In college as a chemical engineering major I took courses in mathematics, physics, chemistry, mechanical engineering, electrical engineering, metalurgical engineering, economics, history, and English. I learned the basic concepts in these fields and how professors in these fields think. None of the majors in these fields ever took a course in chemical engineering. How can we expect college graduates with other majors to understand chemical engineers? In basic research chemical engineers tend to be a minority. They are nice to have around to ease the transfer of research results to development where chemical engineers are in a majority. However, it is clear that chemical engineers even approach basic research different than physicists and chemists. Physicists devote most of their attention to develop instruments to make measurements. Therefore, I define physicists as those that make very accurate measurements on very impure materials. Yes, they do not pay much attention to the material, only to the measurement. While at Exxon I learned that you don’t give a physicist a cup of coffee unless you clearly label it on the outside of the cup. If you do not, the physicist is liable to think the cup contains oil and dump it into his instrument. On the other hand, chemists are very particular about materials. They want to identify every molecule in the material. Therefore, I define chemists as those that make very inacurate measurements on very pure materials. Yes, they are not much concerned about the quality of their instruments, only that they have very pure materials of known chemical structure. I may be biased but I think that chemical engineering combines the best of both chemistry and physics. Therefore, I define chemical engineers as those that make very inaccurate measurements on very impure materials. One might wonder why this is an attribute. In the time it takes the physicist to perfect his instrument and the chemist to purify his material, the chemical engineer has scaled-up, developed, and commercialized a process to manufacture this material. How is this possible? Engineers have learned to deal with uncertainty. Anybody can scale-up and commercialize a process he completely understands. Only a chemical engineer can scale-up and commercialize a process he only partially understands. Chemical engineers have learned to draw a box around part of a system they do not understand and by probing the box and seeing the response, understanding it sufficiently to move on. They do not worry about

the details in this black box that are not necessary to accomplish their goal. They tell people that they invented a field called “fuzzy logic” where they measure variables only qualitatively, like hot and cold. Actually, this is a step-out improvement in accuracy over where they used to be, called “hairy logic”. They use very simple mathematical models. When these models do not correctly predict the data, they do not throw away the models. Instead they calculate the actual to predicted ratios and correlate these ratios on dimensionless plots. They actually give names to these ratios: friction factor, activity coefficient, fugacity, heat transfer coefficient, etc. In order to account for this uncertainty they insert large safety factors in their process design (lagniappe or lan-yap) and in their cost estimates (contingencies). Thus, when the process comes in under budget and delivers at 120% of design, everyone is happy. If you tell a mathematician that he can move towards a pot of gold on the other end of a rope in steps only by cutting the rope in half on each step, he will tell you, “Never mind, I will never get there.” Tell an engineer the same thing and he will say, “Here I go. I will reach it for all practical purposes.” I have asked scientists in different disciplines what they think chemical engineers do. Material scientists think chemical engineers work on material processing. Most chemists picture chemical engineers scaling-up processes, such as with giant test tubes and flasks. Physicists really have no idea what chemical engineers do. They know chemical engineers do many calculations and end up with plants with a lot of pipes. Therefore, they picture chemical engineers as theoretical plumbers. A few years back, a magazine sent out a questioner to a lot of wives about their husbands and correlated the results with the professions of the husbands. They came to the conclusion that chemical engineers make the best husbands. I am sure that women chemical engineers also make the best wives but this was not part of the study. Anyway, the magazine concluded that chemical engineers as husbands were faithful, dependable, helpful, and caring. My daughter says that this is because they are boring. They are not tempted because no one else would have them. There you have it. Now you know what chemical engineers are. It is both a little bit of all of the above and completely none of the above. Whatever it is, chemical engineers are unique and I am happy to be one of them.