Gasoline-like fuels made from cellulosic materials such as farm and forestry waste are on the horizon as chemists at the University of California, Davis, develop a 1-step process that could open up new markets for plant-based fuels.
Biodiesel, refined from plant-based oils, already is commercially available to run modified diesel engines, but Mark Mascal, professor of chemistry at UC-Davis, says a plant-based gasoline replacement would open up a much bigger market for renewable fuels.
Unlike alternative methods of producing green biofuel additives such as ethanol or biodiesel, the university’s new technique yields branched hydrocarbons in the gasoline-volatility range that may be used directly as fuel.
Its developers say it offers the promise of a new generation of biofuel production that does not need additives and is a stand-alone fuel that can be used to directly fuel gasoline-powered vehicles.
“What's exciting is that there are lots of processes to make linear hydrocarbons, but until now nobody has been able to make branched hydrocarbons with volatility in the gasoline range,” he says in a statement.
Traditional diesel fuel is made up of long, straight chains of carbon atoms, while the molecules that make up gasoline are shorter and branched. This means gasoline and diesel evaporate at different temperatures and pressures, reflected in the differing designs of diesel and gasoline engines.
Mascal says the feedstock for the new process is levulinic acid, which can be produced by chemical processing of materials such as straw, corn stalks or even municipal green waste.
“It's a cheap and practical starting point that can be produced from raw biomass with high yield,” he says. “Essentially it could be any cellulosic material.”
Because the process does not rely on fermentation, the cellulose does not have to be converted to sugars first.
UC Davis has filed provisional patents on the process.