The new approach modifies conventional methods for producing liquid fuels from biomass by adding hydrogen from a "carbon-free" energy source, such as solar or nuclear power, during a step called gasification. Adding hydrogen during this step suppresses the formation of carbon dioxide and increases the efficiency of the process, making it possible to produce three times the volume of biofuels from the same quantity of biomass, said Rakesh Agrawal, Purdue's Winthrop E. Stone Distinguished Professor of Chemical Engineering.
The researchers are calling their approach a "hybrid hydrogen-carbon process," or H2CAR.
"Further research is needed to make this a large-scale reality," Agrawal said. "We could use H2CAR to provide a sustainable fuel supply to meet the needs of the entire U.S. transportation sector - all cars, trucks, trains and airplanes."
The process, which would make possible the dawning of a "hydrogen-carbon economy," is detailed in a research paper appearing online this week in the Proceedings of the National Academy of Sciences. The paper was written by Agrawal, chemical engineering doctoral student Navneet R. Singh, and chemical engineering professors Fabio H. Ribeiro and W. Nicholas Delgass.
A conventional method for turning biomass or coal into liquid fuels involves first breaking down the raw material with a chemical process that "gasifies" it into carbon dioxide, carbon monoxide and hydrogen. Then those constituents are turned into a liquid fuel with other processes.
In the H2CAR concept, hydrogen would be harvested by splitting water molecules, possibly with a well-known method called electrolysis. Then the hydrogen