Ernest W. Thiele: A Pioneer in Defining the Role of Diffusion in

13 Ernest W. Thiele: A Pioneer in Defining the Role of Diffusion in Heterogeneous Catalysis

Downloaded by UNIV OF PITTSBURGH on May 3, 2015 | http://pubs.acs.org Publication Date: June 3, 1983 | doi: 10.1021/bk-1983-0222.ch013

RAVI R A N D H A V A Xytel Corporation, Mt. Prospect, IL 60056

Randhava: Dr. Thiele, scientists have gradually developed an appreciation of the important role that diffusion plays in heterogeneous catalysis. Your paper in 1939 provided the theoretical foundation for later developments in this research area; the widely used "Thiele Modulus" attests to the importance of your contribution. Can we talk about this for a few minutes. Thiele:

I'd have to say the whole thing started out at MIT. I was working on my doctor's thesis at that time studying the steam-carbon reaction. Some very peculiar results in kinetics made me think that maybe porous carbon had something to do with the problem. All this was in the early twenties—you have to remember that at that time no one in the oil industry had ever heard of catalysis. For that fact, it was only after Ipatiev wrote his big paper that interest in catalysis caught on in the US. After leaving MIT, I joined Standard Oil of Indiana in 1925. The question of porosity stayed in my mind, since many catalysts are porous. I kept thinking about it for several years and gradually evolved my theory. What we are talking about here is quite straightforward. Small catalyst particles behave very differently from large particles. In small grains, the catalytic action is proportional to the mass of the catalyst; in large grains, to the external surface. All my work on kinetics and the modulus was essentially done in my spare time. My paper was published in 1939. Soon after that, I found out that two other researchers, Damkohler in Germany, and Zeldovich in Russia, had also been working on the same problem and had recently published their results. It just goes to show you that no one is indispensible; if you don't do something, someone else will. The approaches that the three of us followed differed markedly, but we all arrived at essentially the same result: there is a modulus, an expression depending on the diffusivity of the reactants, the rate of reaction, and the size of the grains, which determines the effectiveness of the catalyst mass; if this modulus is low, all the mass is effective; if it is high, only an outer layer is effective. 0097-6156/83/0222-0173$06.00/0 © 1983 American Chemical Society In Heterogeneous Catalysis; Davis, B., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1983.

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What else was going on at Standard Oil in those days?

Thiele:

Keep in mind that I spent almost 35 years at Whiting. At one time or another, I was engaged in just about every aspect of petroleum refining, including a great deal of practical work on catalysts. The Whiting refinery used to be the biggest facility of its type in the world, when I joined in 1925. Executives came up through the ranks of chemical engineers. The general atmosphere towards people in research was not particularly good, but it improved as you went higher. I always said that in those days the lab used to be like a worm. There was little or no organization. Now things are carefully departmentalized. A good deal of my time at Whiting was spent on cat cracking. Everyone was interested in that field. Houdry got Sun Oil involved and they developed a fixed bed process. Standard Oil of New Jersey went ahead and set up a powdered oil process. Most of the early work that I did at Whiting was elementary in nature—things like studying the physical properties of oil. The first noticeable project that I got involved with had to do with delayed coking where you take heavy oil and heat it to a high temperature so that the remains are solid. When I arrived the refinery was using the Burtron process for thermocracking. We set up our first semi-works plant in 1930. We didn't think that we could getaway with anything as small as a pilot plant for delayed coking then. Of course, nowadays people have more experience in designing and building smaller units and things have changed. In addition to cat cracking and coking, we did a lot of work on ultraforming. This was a hot area and we got caught up in a wide variety of pilot plants and catalysts. We also got involved in alkylation using sulfuric acid, a pretty messy process. I'd have to say that over the years at Standard Oil there was literally no end to the number of projects that we handled. I joined Whiting as a chemical engineer, later became a group leader, assistant director of research, and finally their associate director of research. At one time I was in charge of the high pressure lab where I had 70 people, including 10-12 PhD's working forme. Later on they divided up my job and gave it to about three people.

Randhava:

Let's go back a few years. Where did you go to school?

Thiele:

We can start even before that. My parents came to the U.S. from Germany. I was born in 1885 in Chicago, went to Catholic schools in the city, and received an AB degree from Loyola University after studying subjects such as English, philosophy, Latin, and Greek. From there it was on to the University of Illinois at Urbana-Champaign, where I graduated in 1919 with a BS in chemical engineering.


Randhava:

In Heterogeneous Catalysis; Davis, B., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1983.


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Randhava:

What made you decide to go to MIT?

Thiele:

After leaving the University of Illinois, I spent about 6 months as an analyst for Swift & Co. This was followed by a couple of years with People's Gas Light and Coke in Chicago. I was stationed in the lab doing many types of work, and did not receive any formal training, but did gain some useful experience in manufacturing gas. However, even though I had graduated with honors from Illinois, to give you a feeling for how little I knew then, I had no idea that you have to pour reflux back into a column. That's when I realized something was missing and made the decision to go to MIT for my doctor's degree.

Randhava: What happened at MIT? Thiele:

Things were quite exciting there. I started out in the fall of 1922, and got both my master's and doctor's degrees at MIT. My thesis work was on the kinetics of the steam-carbon reaction. I did that under Prof. R. T. Haslam. I specially remember the oral exam for my doctor's degree. Dr. Lewis, the head of the department, was there, along with an instructor, Prof. C. S. Robinson. They were not interested in any meaningless ceremonies and didn't ask me any questions. Lewis remarked that McCabe had an idea for computing columns. I proposed a nomographic technique, showed it to McCabe, and he showed me his method. I knew we had a good thing, drew up most of the figures, and finally left. McCabe had his troubles with department reviewers, but the paper was eventually published.

Randhava:

Dr. Thiele, what are your feelings about scientists like you publishing papers?

Thiele:

I've written and published my share of papers. However, I want to point out that my papers have always been a side issue for me. Most of my life was in business. You musn't expect an enormous number of papers from me because I was not primarily an academic man. What I went after and got a lot of were patents, over 30 in my lifetime. One of my significant patents was on delayed coking. One of my later patents relates to lowering the pour point of steam cylinder oils. We used to take the dirtiest stuff such as low grade asphalt to lower the pour point. As soon as I became associate director of research at Standard Oil, my flow of patents came to a halt.



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Randhava:

To what extent do you think we should rely on industry for funding of research?

Thiele:

It seems right to rely on industry, but the truth is, there's many projects in which, if you expect industry to do it, it will never get done. The government must do many things. Industry doesn't look as far ahead into the future. And there's very large projects that won't work out with industry funding. You can see what's happening with regard to synthetic fuels. Neither government nor industry can make it work. In this case it might reasonably be left to the private sector. I think there's been a tradition of looking a long way ahead that's decreasing.

Randhava: Weren't you involved with nuclear work at one time? Thiele:

Yes, I was. When the project was very young, I was the only engineering technician who worked on the Standard Oil Development Company committee which was investigating the atom bomb. We worked with Arthur Compton on that committee and eventually turned overall our findings to General Grove who ran the Manhattan Project. At about that point from 1942 to 1943, I was given a special project to design and start-up a heavy water separation plant in Trail, British Columbia. I didn't have much faith that they would get this job done in time for the war. The work was extra confidential. One of the techniques we used involved a layer of catalyst between every two bubble trays. You had to get heavy water in the right phase-it resembled distillation. After I returned to Whiting, I got a call from the U.S. Army to go to DuPont to see why their heavy water plant was not working properly. I eventually gave them my opinion about what they could do better. Needless to say, I enjoyed telling DuPont what to do. Sometime during the forties, I also got involved in a project for evaluating nuclear propulsion of aircraft. In 1949 I was engaged as a consultant by the Congressional Joint Committee on Atomic Energy to conduct a major investigation into the possible loss of uranium at Argonne National Laboratory. Some of the senators, especially the one from Iowa, were making a big fuss about this problem. I was paid directly from Senate funds to do this work. A comment and editorial on my report hit the front page of the New York Times.

Randhava: What was going on in the catalysis scene during the war? Thiele:

A lot of major projects were launched, many of them related directly to the war effort. I attended many meetings and seminars. The interesting thing was that the government relaxed many of the


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anti-trust laws. This meant that all of us from different companies could freely get together, exchange ideas, and pool our experience. All the big names would be there: Hensel and the Russians from UOP, people from Texaco, Union Oil, Standard Oil of New Jersey, and many others. Some of the meetings were held in various locations in North Carolina, California, and Mississippi.


Randhava: What happened after you left Standard Oil of Indiana? Thiele:

I thought it was a little early to retire when I left Standard Oil in 1960. I joined the staff of Notre Dame as a visitng professor and spent about 10 years there. Teaching is demanding work, so at age 74 I decided to retire. I wrote a few more papers and reviewed many others. Hopefully I have been able to keep a few bad ones out of the literature. Catalysis continues to be an exciting field with its share of excellent people: Brunauer, Emmett, Wei, Varma, and Carberry to name a few.

Randhava:

What about the work you did with Geddes?

Thiele:

When you go to a refinery, it's 85% distillation. You are dealing with complex mixtures and we both thought that some research on multicomponent distillation was in order. I had been thinking about this area for a long time and had worked out a theory in my head. Like with the modulus, two other people had rival ideas. When our paper was first published, it seemed too long and there were very few applications. I think it was ahead of its time. Later, when computers became available, our work proved very useful.

Randhava:

What has happened with the modulus since you presented it in 1939?

Thiele:

The concept gradually became very popular and is now considered a citation classic. According to the Institute for Scientific Information my work on the modulus was referenced a total of 227 times during the period 1961-1977. Twenty-five years after the paper was published, a graduate student at MIT wrote to say that there was a mistake in one of the equations. I checked it out, and sure enough, he was right. Nobody else had caught this error. Later on, Wheeler did some additional work on my modulus and Hogan and Watson introduced the effectiveness factor.

Randhava:

Dr. Thiele, on behalf of ACS and the entire scientific community, thank you for sharing your thoughts with us. We specially admire your description of your major academic achievements, such as your breakthrough paper on the Thiele modulus, as "side issues", all done only in your spare time.

RECEIVED February 16,

1983


Ernest W. Thiele: A Pioneer in Defining the Role of Diffusion in

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