Turning Waste Material Into Ethanol - Nanoscale Catalysts Could Tap Syngas As Cheap Source Of Ethanol

Main Category: Biology / Biochemistry
Also Included In: Water - Air Quality / Agriculture
Article Date: 14 Aug 2008 - 3:00 PDT

email to a friend   printer friendly   view / write opinions   rate article

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.

"If we can increase this 'activated' CO adsorption on the surface of the catalyst, it improves the opportunity for the formation of ethanol molecules," Lin said. "And if we can increase the amount of surface area for the catalyst, we can increase the amount of ethanol produced."

Lin's group looked at using a metal alloy as the catalyst. To increase the surface area, they used nano-scale catalyst particles dispersed widely within the structure of mesoporous nanospheres, tiny sponge-like balls with thousands of channels running through them. The total surface area of these dispersed catalyst nanoparticles is roughly 100 times greater than the surface area you'd get with the same quantity of catalyst material in larger, macro-scale particles.

It is also important to control the chemical makeup of the syngas. Researchers at ISU's Center for Sustainable Environmental Technologies , or CSET, have spent several years developing fluidized bed gasifiers to provide reliable operation and high-quality syngas for applications ranging from replacing natural gas in grain ethanol plants to providing hydrogen for fuel cells.

"Gasification to ethanol has received increasing attention as an attractive approach to reaching the Federal Renewable Fuel Standard of 36 billion gallons of biofuel," said Robert Brown, CSET director.

"The great thing about using syngas to produce ethanol is that it expands the kinds of materials that can be converted into fuels," Lin said. "You can use the waste product from the distilling process or any number of other sources of biomass, such as switchgrass or wood pulp. Basically any carbon-based material can be converted into syngas. And once we have syngas, we can turn that into ethanol."

The research is funded by the DOE's Offices of Basic Energy Sciences and Energy Efficiency and Renewable Energy.

Ames Laboratory is a U.S. Department of Energy Office of Science laboratory operated for the DOE by Iowa State University . The Lab conducts research into various areas of national concern, including the synthesis and study of new materials, energy resources, high-speed computer design, and environmental cleanup and restoration.

DOE/Ames Laboratory