Preserving the Environment

How Deep-Fried Food Can Reduce Our Fossil Fuel Addiction

December 26, 2014
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How Deep-Fried Food Can Reduce Our Fossil Fuel Addiction
Biodiesel motor fuel can be made from waste oils generated by commercial kitchens. Oli Scarff/Getty Images
Meet the scientists refining cooking grease into biodiesel.

You’d expect that oils from McDonald’s deep-fryer traps, fat from slaughtered pigs and cattle and the grease caught in city sewer traps would be pretty much useless, right? But two researchers are investigating how to recycle all those leftover oils and fats into biodiesel motor fuel, an alternative that can reduce our dependence on oil.

After a decade in the lab, two Minnesota chemical engineers are designing a plant that will convert yellow and brown grease into fuel. With so many experiments, they’ve found a way that’s cheaper and more energy-efficient than the alternatives, like soybean-based biodiesel. Kirk Cobb and Joe Valdespino, the brains behind Superior Process Technologies, a little-known chemical company in Minneapolis, will soon have their ideas put into practice at a full-scale refinery near downtown Los Angeles that can churn out 20 million gallons of biodiesel annually.

“Our process is superior to the traditional method,” Valdespino tells the Minneapolis Star Tribune. “It saves energy. It increases yield. It enables you to use cheaper feedstocks,” he says, referring to the raw material inputted to machines.

Biodiesel took off after major environmental legislation in 2005 and 2007 and a farm bill in 2008 that contained several incentives. At the last count by the U.S. Energy Information Administration, the country has roughly 100 producers, with most output clustered in the Midwestern states of Texas, Iowa, Missouri and Illinois. Most of them rely on soybean, canola and corn oils for their raw material — about 2.2 billion pounds worth just in the first half of this year. Animal fats (403 million pounds) and other recycled grease (535 million pounds), on the other hand, lag behind in the industry.

Cobb and Valdespino are hoping greater efficiency will change that. The pair became friends fifteen years ago while working for a paper company in Savannah, Ga., where they converted resin from the pulp of pine trees into profitable adhesives, plastics and inks. After 24 years on the job, Cobb left to work on biodiesel at Superior Process Technologies in 2004 and hired Valdespino in 2007.

Since then, they’ve been laying the groundwork for a tactic that diverges from the rest of the field. Other refiners add sulfuric acid to remove fat, but that reaction creates water which contaminates other key compounds like methanol and must be removed — a “really messy” and “very limited” business, Valdespino says. Their company adds glycerol at around 450 degrees, enough heat to evaporate the water and skip the extra step of eliminating impurities.

“People misconstrue higher temperatures with higher energy use,” says Cobb. “That is not the case.” Cobb says the plant will be able to do the job better — using six times less energy than the standard method — and provide diesel to large customers like airliners and the Navy at lower prices.

Almost all the industry’s innovation had been fueled by hefty support from the federal government, but most of those tax credits, loans and grants recently expired. Cobb and Valdespino are hoping the incentives return, so that for once, greasy fat can actually do something good for America.

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