A little soy oil can go a long way. Agricultural Research Service (ARS) scientists report that after winterizing, 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 U.S. 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). Dunn has developed a three-step winterization process for biodiesel fuel that involves mixing in additives, chilling the fuel and filtering out solids.

In previous tests, Dunn produced biodiesel fuels capable of starting diesel engines at temperatures as low as 5 degrees Fahrenheit, making them comparable to petroleum-based diesel fuels. Using biodiesel fuel blends that haven't been winterized could limit 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: 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 temperature is low enough. The 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 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 U.S. currently imports 50% of its oil at a cost of $60 billion annually.

Another plus: Biodiesel is nonflammable, making it relatively safe to store and handle and environmentally innocuous because it's biodegradable.

For more information from ARS, long on to www.ars.usda.gov/is/pr/thelatest.htm .