Cutting greenhouse gases: wood chips in, alcohol out

California researchers plan to make biofuels in a novel way that doesn’t involve food crops or microbial fermentation

California researchers plan to make biofuels in a novel way that doesn’t involve food crops or microbial fermentation. A new research effort involving three University of California campuses and West Biofuels LLC, will develop a prototype research reactor that will use steam, sand and catalysts to efficiently convert forest, urban, and agricultural “cellulosic” wastes that would otherwise go to landfills into alcohol that can be used as a gasoline additive.

“We have a very feasible design to combine individual components of technology that have been proven separately into a successful biomass processing prototype,” said Robert Cattolica, leader of the research program and a professor of mechanical and aerospace engineering at UC San Diego’s Jacobs School of Engineering. Cattolica is the principal investigator of the project, which includes researchers at UC San Diego, Davis, and Berkeley.

Since carbon dioxide is naturally recycled from the atmosphere into cellulose in plants and back into the atmosphere as carbon dioxide when plants decompose, burning biomass-derived fuel such as alcohol in internal combustion engines has a zero net effect on the amount of carbon dioxide in the atmosphere. On the other hand, burning fossil fuels continually adds carbon dioxide, a greenhouse gas, to the atmosphere.

The new biofuels research project was inspired by California’s Global Warming Solutions Act, which was signed into law by Governor Arnold Schwarzenegger in September 2006. The act requires a 25 percent reduction in greenhouse gas emissions in California by 2025. Substituting biomass fuel for petroleum would help California achieve its goal. The two-year UC project is funded with a $1.85 million grant from West Biofuels LLC, a San Rafael, CA, company that is developing the biomass-to-alcohol technology, and a $1.15 million state-funded UC Discovery Grant.

“My company is excited about partnering with the University of California on a very promising technology that could eventually have a significant beneficial impact on our environment while also reducing California's reliance on oil imports,” said Peter Paul, chief executive officer of West Biofuels.

The alcohol currently added to gasoline sold in California is derived from corn, sugar cane, beets, or other farm crops. About 95 percent of the alcohol additive comes from outside of California and as far away as China. Rather than fermenting food crops into ethanol, Cattolica’s project will use a thermo chemical process to break down shredded cellulosic wastes into a mixed alcohol, predominately ethanol. “The technology we’re developing will tap a huge, energy-rich resource that now is literally going to waste,” said Cattolica.

The prototype reactor will mix the wastes with high temperature sand in a reaction chamber while the mixture is heated with steam. The gasification process generates an energy rich combination of hydrogen (H2), carbon monoxide (CO), methane (CH4), and carbon dioxide (CO2). Those gases will be catalytically “reformed” into alcohols. About 30 percent of the energy content of the starting material will be burned to supply the energy needed to operate the plant.