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By Jim Core
April 16, 2002
Biodiesel is traditionally made from
agricultural lipids such as fats and oils. These highly refined edible oils are
renewable resources that reduce air-polluting emissions from diesel engines.
Now, scientists at the Agricultural
Research Service have developed a biodiesel fuel produced from soybean
soapstock, an abundant but underutilized byproduct of vegetable oil refining.
The new biodiesels composition, engine performance and emissions are
comparable to those of biodiesel fuels now on the market.
Scientists at the ARS Eastern Regional
Research Center in Wyndmoor, Pa., have studied the use of lower-value
lipids from animal fats, vegetable oils and recycled greases as raw materials
for biodiesel production. ARS research chemist Michael J. Haas and biologist
Karen M. Scott teamed with Scott Bloomer, then at
Cargill in Minneapolis, Minn., to develop
a chemical method that converts all forms of fatty acids found in the lipids of
soybean soapstock into simple methyl esters, a compound in biodiesel fuel. The
researchers were recently granted a patent for the process.
Many commercially available biodiesel fuels are made from refined soy oil
and added to diesel, typically at levels of 20 percent of the mixtures
volume. According to Haas, studies show that biodiesel, used alone or in such
blends, can provide much-needed lubrication to fuel systems, while also
reducing the production of polluting exhaust emissions. Now Haas, Scott and
Bloomer have modified the technology to allow the use of lower-value, less-pure
lipids, such as soapstock, as starting materials.
Soybean oil soapstock is a plentiful and relatively inexpensive byproduct of
edible oil refining. About 100 million pounds of the soapstock are produced in
the United States every year, and it can cost as little as one-tenth or less of
the price of refined vegetable oil. Currently, it is used mostly as a cheap
source of fat in livestock feeds. However, by implementing processes such as
that developed by Haas and Bloomer, the agents in soapstock could one day serve
as the source of diesel engine fuel or fuel additives and in other applications
such as cleaning agents and organic solvents.
More information can be found in the
April 2002 issue of
Agricultural Research magazine.
ARS is the U.S. Department of
Agricultures chief scientific research agency.