
NIR Helps Turn Vegetable Oil into
High-Quality Biofuel By Linda
McGraw June 15, 1999PEORIA, Ill., June 15--To help
speed the development of biodiesel fuels made with vegetable oils, scientists
at USDA's Agricultural Research Servicehere have adapted a sophisticated tool known as near-infrared spectroscopy, or
NIR. Baby-boomers remember the lines at gas stations when the oil embargo of the
1970's hit. Despite the oil shortage, America's farm tractors continued to roll
because of USDA research that turned
vegetable oils into alternative fuels. The trend will continue in the 21st century, when motorists will see more
public vehicles--buses, trains, trucks, and government-owned maintenance
equipment--running on biodiesel fuels made from soybean oil. By the year 2001,
the Federal Energy Policy Act requires that 75 percent of all new state and
federal vehicles be filled with alternative fuels. Until now, the standard for measuring biodiesel quality has been a complex
analytical method called gas chromatography, or simply GC. "But GC is a complex piece of laboratory equipment, requiring technical
expertise and at least an hour to perform," said Gerhard H. Knothe, an ARS
chemist in Peoria, Ill. Another drawback of GC is it requires chemical reagents
and solvents that need special handling and costly disposal. Knothe has developed a safer and faster way to check the quality of
biodiesel fuel by using NIR. Much of the pioneering work on biodiesel fuels
began where Knothe works, at ARS' National
Center for Agricultural Utilization Research. "NIR is a nifty tool also used for determining fatty acid composition
in vegetable oils and oil content in seeds," said Knothe. Another plus: No
special training is needed to perform the NIR test. The researchers are developing the method for more effective production
monitoring and fuel quality control, improvements needed by the biodiesel
producers. Biodiesel producers need to know early if the chemical reactions
that occur during biodiesel fuel production are successful. Using NIR, Knothe can measure the conversion of vegetable oil to biodiesel
fuel in less than a minute. NIR coupled with a fiber-optic probe uses light rather than chemicals to
perform the analysis. Checking the biodiesel fuel quality is important because
potential contaminants in the fuel could lead to engine deposits. "Our
test will help biodiesel fuel producers determine if their products meet the
quality standards of the American Society for Testing and Materials,"
Knothe said. Scientific contact: Gerhard H. Knothe, Oil Chemical Research Unit,
ARS National Center for Agricultural Utilization Research, Peoria, Ill., phone
(309) 681-6417, fax (309) 681-6340,
[email protected].
U.S. Department of Agriculture | |