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 new type of fuel additive made from soybeans could
help reduce energy costs and our dependence on imported crude
oil, researchers at the University of Kansas report.
 The researchers
said fuel additives made from soybean oil improve the performance
of diesel fuel and, in particular, of diesel fuel containing
ethanol. When the additive is used in combination with 10 percent
ethanol in diesel, significant reductions in emissions can be
achieved.
Galen Suppes,
KU associate professor of chemical engineering, and Joseph Heppert,
KU associate professor of chemistry, developed and evaluated
formulas for soybean oil-based cetane improvers with very good
results.
"Our
goal was to match the ignition value of commercial additives,"
Suppes said. The research team did just that, and they discovered
something more -- their soybean-oil based additives improve fuel
lubricity, an important factor in the performance of fuel-injected
engines. When paired with the diesel/ethanol fuel blend, soybean-oil
cetane improvers help reduce greenhouse gas emissions while stimulating
state and local farm economies.
Cetane
improvers are commonly added to make the fuel ignite faster,
which reduces harmful exhaust emissions. Diesel fuels are given
a cetane rating or number that correlates with how long it takes
fuel to ignite once it has begun to be injected into the engine's
cylinder. This is commonly referred to as ignition delay time.
Shorter ignition delay times reduce harmful nitrogen oxide gas
emissions, and they result in faster engine start-up in cold
weather along with smoother engine operation overall. Commercial
cetane improvers are derived from petroleum. The soybean oil-based
additives developed by Suppes and Heppert are the first of their
type.
Suppes
and Heppert used a blend of 10 percent ethanol and 90 percent
diesel fuel in a Volkswagen test engine. They saw reductions
in the amount of particulate matter in the engine exhaust of
more than 30-50 percent compared to unblended diesel. The opacity
of exhaust smoke dropped, too.
Suppes
said the fuel blend, sometimes called "diesehol," is
tied closely to cetane improvers because when ethanol is added
to diesel fuel, the cetane number and the lubricity of the diesel
can be compromised. Ethanol fuel releases fewer pollutants into
the environment, but it has trouble igniting and burning at low
temperatures. That's where the KU team's additives are especially
important.
"Soybean
oil-based additives are ideally suited to use in diesel to great
advantage because they increase lubricity while improving the
cetane rating," Suppes said. Commercial petroleum-derived
additives do not improve lubricity.
The new
additive is effective in very small quantities: it takes only
500 parts per million to have full effect. Suppes said the researchers
target the retail cost of their additive at 40 cents per gallon
when manufactured at a commercial production level. Currently
used additives cost more. In addition, Suppes said the value
of the new additive exceeds its cost value because of the benefit
of lubricity. Plus, soybean oil-based additives are a renewable
resource.
Ethanol
fuel is manufactured from corn and grain sorghum. Ethanol production
is the third largest user of corn in the US, behind feed and
export uses, according to a report submitted at the Midwestern
Governors' Conference.
"Higher
diesel and gasoline prices create a real opportunity to start
to use ethanol and alternative synthetic fuels," Suppes
said. "The use of these fuels has a positive impact because
they are cleaner burning, they reduce our dependency on imported
crude oil, and they can stimulate farm economies.
"Diesel
engines are typically 30 percent more efficient than gas engines.
Their use has a more than 23 percent reduction in fuel consumption,"
he said. "If you're going to use ethanol, it's by far more
advantageous to use it in a more efficient engine because ethanol
costs more."
Suppes
notes that the cost to consumers of cars and trucks with diesel
engines makes them unpopular, but they don't have to be more
expensive.
"In
Europe, the cost of a diesel engine is similar to a gas engine,"
Suppes said. "Europe maintains a little better quality control
on diesel fuel, and they have better diesel engines that they
can mass produce. The bottom line is you don't have to pay more;
you just need to create a situation where there are enough engines
in use."
The team
will present its findings at an international conference in Paris
in June. The research was supported by the Kansas Soybean Commission,
the USDA and Mid-Continental Chemical Co., Inc., in Lea-wood.
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