LAWRENCE, Kans. -- A recipe for an alternative diesel fuel using agriculture resources found in Kansas begins with a liberal dose of something not normally used in engine fuels - sugar.
The primary goal of a University of Kansas researcher is to demonstrate technology that can convert grass, stalks, trash, farm byproducts, surplus grains and corn stover - corn stalks without the ears - into sugar for use as the primary component in fuel for diesel engines.
"It's not a question of if sugar will work," said Galen Suppes, assistant professor of chemical and petroleum engineering. "It's only a question of when these fuels will be less expensive than diesel fuels."
Suppes estimates that this alternative fuel using sugars "costs considerably less than ethanol or methanol made from biomass and should cost less than diesel."
"We know the technology is there to convert many forms of biomass to sugars," Suppes said. "In fact, we are developing technology to give these fuels exceptional fuel quality. The problem is one of perception - of using sugar as the primary component of a fuel recipe."
In fact, he said, KU researchers have already made these fuels run in conventional diesel engines. Tests have been so successful that a provisional patent application has been filed with the U.S. Patent Office on the fuel mixtures, with a final patent application expected to be filed this summer.
"It's better to plan ahead and work with engine manufacturers and develop engines which can use both conventional and alternative diesel fuels," he said.
According to Suppes, you normally can't use sugar in a gas engine. "Gas engines have injectors and carburetors that rely on fuel evaporating, and sugar doesn't evaporate," he said.
Diesel engines are different, he said, because the fuel is sprayed into the cylinder at very high temperatures, where it evaporates, burns and ignites before it can solidify.
"Placing sugar directly into diesel fuel would also foul up the system," Suppes said. "But put sugar in a soluble mixture, and you have a viable alternative fuel."
In fact, research shows that a diesel fuel composed of nearly 15 percent water, 20 percent to 30 percent methanol or ethanol, and 50 percent to 75 percent syrup - water and sugar - is an attractive recipe for the fuel.
What is missing from the equation is the proper amount of cetane improver. Cetane numbers rate the ignition properties of diesel fuels, just as octane numbers determine the quality and value of gasoline.
A recent diesel engine test at KU was successful using a fuel mixture of 54 percent syrup - 7.5 grams water and 46.5 grams of sugar; 8 percent cetane improver; and 38 percent methanol.
"The demonstration of a fuel comprised of greater than 50 percent syrup was a significant research milestone," Suppes said. "It will be easier to improve upon this fuel than it was to make the initial demonstration. We intend to meet the goal of being less expensive than diesel for select markets by 2005."
Researchers at KU have developed a combuster, a device to estimate cetane numbers. By blending and synthesizing fuels and additives, they evaluate the cetane numbers in the combuster.
Once a desirable fuel blend is found, it is tested in a laboratory engine. Funding for cetane-improver research into conventional diesel fuel comes from the Kansas Soybean Commission, the KU Energy Research Center and the Kansas Value Added Center.
Suppes said a partnership initiated between the U.S. government and Ford, Chrysler and General Motors expected diesel engines to replace gas engines by 2010.
"Economically competitive fuels and fuel additives could provide a large source of revenue and new jobs in Kansas," he said. "Surplus grain commodities could be used in these biofuel markets to eliminate the reductions in grain prices which occur during years of high and record production."
Suppes also suspects that such markets could double the net farm income of farmers and lead to sustainable prosperity in rural Kansas.