SQUEEZING CLEAN FUEL FROM COAL
How to convert coal into cleaner syngas

Diamonds aren’t the only valuable byproduct of coal. At LSU, researchers supported by the U.S. Department of Energy and Conoco-Phillips have joined with Clemson University and Oak Ridge National Laboratories, or ORNL, to show that ethanol, one of the cleanest burning alternative fuels available, can be made from something as unassuming—and unappealing—as a lump of coal.

“We’re working with our project partners to produce ethanol from a coal-derived syngas, a mixture of primarily carbon monoxide and hydrogen,” said James Spivey, McLaurin Shivers professor of chemical engineering and principal investigator of the project. “Because ethanol is a liquid, it can be more easily distributed to the end user than gaseous hydrogen. It can be converted into a hydrogen-rich gas at the point of use, such as a fuel cell.”

Among other uses, liquid ethanol serves as one way to transport hydrogen since the atoms contained in an ethanol molecule can be “reformed” into clean, gaseous hydrogen at the point of use. Hydrogen is one of the cleanest fuels available but cannot be transported easily as a gas. Ethanol, which can be used alone or blended with other liquid fuels, makes this possible.

But why start with coal?

“Coal is the most abundant source of energy in the world, and in the U.S., so-called renewable resources can only supply a small fraction of our energy needs in the foreseeable future—even under the most optimistic assumptions,” said Spivey. “There is three times more energy in U.S. coal than there is in all the oil in the Middle-East. It only makes sense to use it.”

Before it can be used in a clean and efficient way, solid coal must be turned into gaseous form. “In the gasification process, coal reacts with steam and oxygen to produce syngas,” said Spivey. “The syngas is then converted into a useful fuel like ethanol in the catalytic process that is currently being developed.”

Spivey and graduate students Femi Egbebi and Nachal Subramanian are working to prepare and test these catalysts. Challa Kumar, group leader of nanofabrication at the Center for Advanced Microstructures and Devices, or CAMD, is utilizing the synchrotron radiation-based X-ray absorption spectroscopy tools and wet-chemical synthesis capabilities to prepare new catalysts identified using computational simulations carried out at Clemson. ORNL is using special equipment to probe the structure of these catalysts, while Conoco-Phillips carries out economic evaluations to determine if a viable process can be developed.

Turning coal into clean-burning fuel is a challenge, Spivey acknowledges, but worthwhile. “The DOE is definitely interested in seeing a commercial project come out of this,” he said. “Our project team is committed to making this happen. A successful project will help show that LSU is focused on research that makes sense for the environment and for our country.”

—Ashley Berthelot

...from the Autumn 2007 Issue