Plants + process = fuel
A team of chemical engineers has developed a highly efficient, environmentally friendly process that selectively converts gamma-valerolactone, a biomass derivative, into the chemical equivalent of jet fuel. The simple process preserves about 95 percent of the energy from the original biomass, requires little hydrogen input, and captures carbon dioxide under high pressure for future beneficial use.
With Steenbock Professor of Chemical and Biological Engineering James Dumesic, postdoctoral researchers Jesse Bond and David Martin Alonso and graduate students Dong Wang and Ryan West published details of the advance in the February 26, 2010, edition of the journal Science. Much of the Dumesic group’s previous research of cellulosic biomass has focused on processes that convert abundant plant-based sugars into transportation fuels.
However, in previously studied conversion methods, sugar molecules frequently degrade to form levulinic acid and formic acid — two products the previous methods couldn’t readily transform into high-energy liquid fuels.
With levulinic and formic acid as the starting points, the team’s new method exploits sugar’s tendency to degrade. In the presence of metal catalysts, the two acids react to form gamma-valerolactone, or GVL, which now is manufactured in small quantities as an herbal food and perfume additive. Using laboratory-scale equipment and stable, inexpensive catalysts, Dumesic’s group converts aqueous solutions of GVL into jet fuel.
“With very minimal processing, we can produce a pure stream of jet-fuel-range alkenes and a fairly pure stream of carbon dioxide,” says Bond, of the two-step catalytic process.
The hydrocarbons produced from GVL in this new process are chemically equivalent to those used in the present infrastructure. “The product we make is ready for the jet fuel application and can be added to existing hydrocarbon blends, as needed, to meet specs,” says Alonso.
Now that they have demonstrated the process for converting GVL to transportation fuel, Dumesic and his students are developing more efficient, cost-effective methods for making GVL from biomass sources such as wood, corn stover, switchgrass and others. “Once the GVL is made effectively, I think this is an excellent way to convert it to jet fuel,” says Dumesic.