Clean air and large profits

US Agricultural Research Service scientists report that after winterising, biodiesel fuel that contains soy oil can be safely blended with noncommercial jet fuel used in military aircraft. The ultimate payoff will be cleaner air and larger profits for US soybean growers.

In laboratory studies, ARS chemical engineer Robert O. Dunn added small amounts of methyl soyate (SME) - esters from fatty acids of soybean oil- with noncommercial jet fuel (JP-8) to concoct the mixture.

He also developed a three-step winterization process for the biodiesel fuel that involved mixing in additives, chilling the fuel and filtering out solids. Using biodiesel fuel blends that haven't been winterized could limit an aircraft's ability to fly at high altitudes, where cold temperatures can cause crystal formation, blocking fuel filters and plugging fuel lines.

The most promising aspect of this work so far is that the winterized SME did not form solid particles when exposed to a range of slightly below zero to -52 degrees F in the laboratory.

But eventually, even winterized SME blends will form solid particles when the temperature is low enough. So research continues to expand the lower limits of temperature so that winterized, blended biodiesel fuels can function safely in military aircraft.

The impetus behind the research comes from the US Clean Air Act and its more recent amendments that call for a reduction of harmful emissions from commercial and military aircraft.

Biodiesel is a renewable commodity and produced domestically. The US currently imports 50 percent of its oil at a cost of $60 billion annually.

A full report of this research can be found in the July issue of Agricultural Research magazine, which is online at:

http://www.ars.usda.gov/is/AR/archive/jul01/jet0701.htm