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10 Questions for a Chemical Engineer: Steven Sherman

May 19, 2011 - 4:18pm

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Chemical Engineer Steven Sherman | Photo Courtesy of SRNL

Chemical Engineer Steven Sherman | Photo Courtesy of SRNL

Hailing from Savannah River National Laboratory, Dr. Steven Sherman recently shared how he’s working to develop bioenergy and nuclear energy technologies and how he’s helping South Carolina advance its leadership in biofuels. Also, find out about his work to get additional useful products from plants, such as lignin which could potentially be used to produce strong, lightweight fibers for car panels.

Question: What sparked your interest to pursue a career in science?

Steven Sherman: I have been interested in science from my earliest memories. When my twin brother and I were very young, my father, who grew up in rural West Virginia, used to take us into the woods for hikes. He would point out the names of plants and animals and invite us to watch for squirrels, deer and birds. We would also look for fossils or minerals in the soil, or in an exposed creek bed. At night, we would look at the stars, and would occasionally spot an artificial satellite or meteor. My grandfather also knew the forest. I remember one visit with him where he made whistles for us out of a maple tree branch. My mother's parents lived near the ocean, and I remember many trips there to play in the water, to pick up shells or other "treasures,” or just to watch the birds and the crabs do their dance as the waves came in and out. All of these visits impressed upon me that the world is filled with fascinating things that move and grow and change according to their own rules, and I never grew tired of wanting to know more.

When I was a little older, I was captivated by two public television series which caught my attention at a critical time -- Cosmos by Carl Sagan and Life on Earth by Sir David Attenborough. These two shows were truly excellent and really convinced me that the study of science was what I wanted to do when I grew up.

Of course, no one event was the pivotal moment in making a decision to pursue science, and my parents were very supportive of education and self study. My brother and I participated in elementary school science fairs. We went through phases where dinosaurs were king, followed by astronauts. We had a telescope. We had free access to the local library where we would frequently ride our bikes to check out books. My family was also an early adopter of the home computer. My parents, who were medical technologists, kept all of their textbooks from college. I remember looking through their biology and medical textbooks all of the time just to look at the pictures. None of these things by themselves would necessarily lead to a career in science, but together, they helped build and reinforce my interest in a science-oriented career.

Q: What led you to chemical engineering?

SS: I had an excellent chemistry teacher in high school, and he really sparked my interest in chemistry. However, I chose chemical engineering over chemistry rather deliberately. I read about chemistry career fields, and even visited a few colleges and universities in my junior year in high school. I eventually decided that I really wanted to be an engineer rather than a chemist. I liked the idea of applying chemistry to help meet people's needs. I was also attracted to the reputation of the chemical engineering curriculum, which was said to be quite difficult, and I wanted to be challenged. To this day, I am very glad that I took the engineering road.

Q: What projects are you working on right now? What do you hope they will lead to?

SS: At this time, I am working on alternative energy projects in the bioenergy and nuclear areas. In the bioenergy area, I am working on developing chemical processes to convert feedstocks such as switchgrass, sweet sorghum and woody materials into ethanol and other chemicals. In the nuclear area, I am helping support a small piece of the ITER project, which is a project to build a full-scale nuclear fusion plant in Cadarache, France.

These projects support the development and technological advancement of new ways to make the fuels and electrical power that we need to enable our way of life and to provide more environmentally sustainable ways of supporting ourselves. The population of the planet is huge and still growing, and continuing down the path of widespread fossil fuel use is not sustainable. The world needs options and these projects contribute, in their small way, to providing some of those options.

Q: Do you have advice for students interested in becoming scientists?

SS: I encourage any young person interested in science to open themselves up to it. Science is not just a body of accumulated knowledge, but is a process and a way of thinking. It is learned by doing as well as studying, and I encourage people to synthesize, experiment, observe and analyze. It is also important to cultivate critical thinking skills and apply them to what we observe, what we are told and to our underlying assumptions. The subjects of scientific inquiry are vast, but the approach and thinking styles adopted by the best scientists and engineers are the same. Skills in critical thinking and careful observation are the most important skills to cultivate in any scientific career.

As a caution, I encourage students to occasionally "unplug" from their digital devices. More and more our activities and interactions are defined by digital devices -- smart phones, iPods, computers, game players. It is important to break outside of our digital environment, at least occasionally, and observe the natural world. Even the best computer simulations are imperfect, and there can be surprises when comparing computer results to actual events.

Lastly, I encourage anyone interested in science to learn to become a good writer. Written communication of scientific and technical information is critical to the performance of science and is the principal means of communication in the scientific world. People judge the merits of technical work not only on the subject of the work, but also on the quality of the writing. Be aware of the needs of the reader, use standard syntax and spelling, and practice, practice, practice!

Q: Can you tell us about your work with the South Carolina Bioenergy Collaborative?

SS: The South Carolina Bioenergy Collaborative is a research collaboration between Clemson University and Savannah River National Laboratory. Our mission is to develop technologies to enable the conversion of lignocellulosic feedstocks such as switchgrass, sweet sorghum, and trees into bio-fuels and other chemicals. We are focused on using crops that grow well in the southeastern United States and that could be grown on farms or in areas currently under-used or that lie fallow. Our overall economic goal is to help build a thriving biotechnology industry in the Southeast, which can support greater prosperity for rural areas and can help lower consumption of imported petroleum. Our collaborative is interested in the whole process, from harvest to fuel purification, and is working with outside companies such as Fagen Engineering, Arborgen, and Dyadic International to help develop the process.

My particular work with this project involves working out the chemical steps for extracting and purifying potential value-added co-products from the feedstock materials to supplement the basic fuel production process. In our process, ethanol is produced by fermenting sugars produced by the enzymatic digestion of cellulose and hemicellulose. Economically, manufacturers would do better if they could make more than one thing from these feedstock materials and that is the area in which I am working.

One particular co-product I am interested in is lignin. All land-based plants contain lignin, a brown polymeric material that adds strength and water resistance to plant stems, limbs and leaves. Lignin has some industrial uses, but it also has great potential as a raw material for advanced polymers, chemicals and even carbon fibers for car bodies. We are learning how to extract and purify lignin at low cost so that future markets for lignin-based products may be supported by large supplies of inexpensive lignin. We are also interested in generating hemicellulose as a separate sugar stream that can be converted into other valuable chemicals besides ethanol.

Q: Can you expand a bit on the potential for lignin applications?

SS: Lignin is currently generated on a large scale in the paper pulping industry, but most of that lignin is burned to make steam and to recover process chemicals in the highly integrated paper pulping processes. The current market for lignin is not large and all needs are met by pulling excess material from the paper pulping industry. Future applications for lignin are under study, and if any of these potential uses comes to fruition, the market demand for lignin could greatly exceed what can be supplied by the paper pulping industry.

Lignin is rich in aromatic compounds and could potentially be used as a widely available source of chemicals or fuel additives, if efficient and cost-effective means are found to break up the lignin into its constituents. Oak Ridge National Laboratory is piloting the manufacture of carbon fibers from hardwood lignin, which could lead to lower-cost carbon fiber composites and lightweight, strong fiber composite panels for car bodies at the same cost as today’s metal panels. As we work on the process for purifying lignin, we will continue our work to characterize the lignin we separate and identify potential uses of that lignin in the marketplace.

Q: Where do you see these technologies over the next several years?

SS: All of these technologies that I've described are at the developmental stage. Getting these technologies to commercialization is the driving force and motivation for much of this work in the United States. These processes are not being developed just because they are interesting, but because the United States needs to diversify its energy supplies. Bioenergy is one way of doing that. The United States is rich in land and agricultural resources and we have the know-how to meet a large percentage of our fuel needs domestically using materials grown locally. We are not there yet and costs are still too high. All of our work is directed towards lowering processing costs through gains in energy efficiency, better chemistry, process intensification and any other method that may lower costs.

Q: What can you never start a day at the lab without?

SS: Reading the day's news over breakfast on my Kindle. The world is a complicated place, and I am always reminded why we do our work when I read the headlines.

Q: Do you have a favorite tool in the lab?

SS: Lab notebook. No matter what experiment you are doing, and no matter what equipment you are using, the lab notebook is the one place where data, observations, work history, and analysis come together in one place.

Q: What do you enjoying doing in your free time?

SS: Long-distance running, triathlons, practicing my guitar, reading and fly fishing.

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