Fewer Exhaust Emissions May Come from Soybean Oil in Jet Fuels
By Linda McGraw
July 9, 2001
A little soy oil can go a long way.
Agricultural Research Service 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
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 havent
been winterized could limit aircrafts 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
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 percent 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 its biodegradable.
A full report of this research can be found in the July issue of Agricultural Research magazine.