Turning Waste Material into Ethanol

Physorg.com
15:46 EST, August 13, 2008

(PhysOrg.com) -- Say the word “biofuels” and most people think of grain ethanol and biodiesel. But there’s another, older technology called gasification that’s getting a new look from researchers at the U.S. Department of Energy’s Ames Laboratory and Iowa State University. By combining gasification with high-tech nanoscale porous catalysts, they hope to create ethanol from a wide range of biomass, including distiller’s grain left over from ethanol production, corn stover from the field, grass, wood pulp, animal waste, and garbage.

Gasification is a process that turns carbon-based feedstocks under high temperature and pressure in an oxygen-controlled atmosphere into synthesis gas, or syngas. Syngas is made up primarily of carbon monoxide and hydrogen (more than 85 percent by volume) and smaller quantities of carbon dioxide and methane.

It’s basically the same technique that was used to extract the gas from coal that fueled gas light fixtures prior to the advent of the electric light bulb. The advantage of gasification compared to fermentation technologies is that it can be used in a variety of applications, including process heat, electric power generation, and synthesis of commodity chemicals and fuels.

“There was some interest in converting syngas into ethanol during the first oil crisis back in the 70s,” said Ames Lab chemist and Chemical and Biological Science Program Director Victor Lin. “The problem was that catalysis technology at that time didn’t allow selectivity in the byproducts. They could produce ethanol, but you’d also get methane, aldehydes and a number of other undesirable products.”

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