Every dipstick knows an oil change every few thousand miles is a routine way of prolonging the engine life on your car or truck. But doing so produces an estimated 8 billion gallons of used motor oil. Though some of it can be re-refined into new oil or burned in furnaces for heat, often the used oil is simply thrown away.
In a nod to practicing better environmental maintenance, researchers at the University of Cambridge in the United Kingdom recently announced development of a process that uses microwaves to more thoroughly covert waste crankcase oil into vehicle fuel.
“Transforming used motor oil into gasoline can help solve two problems at once,” said study leader Howard Chase, Professor of Biochemical Engineering at the University of Cambridge. “It provides a new use for a waste material that’s too-often disposed of improperly, with harm to the environment. In addition, it provides a supplemental fuel source for an energy-hungry world.”
Along with doctoral students Su Shiung Lam and Alan Russel, Chase presented his findings at a meeting of the American Chemical Society
A process known as pyrolysis already exists for recycling oil that involves heating it to a high temperature in the absence of oxygen. Pyrolysis breaks down the oil into a mixture of gases, liquids and solids. The gases and liquids can be converted into gasoline or diesel fuel, though not very easily. Current methods of pyrolysis heat the oil unevenly, causing the fuel conversion to be difficult and inefficient.
In their new method of pyrolysis, researchers combined samples of waste oil with a highly microwave-absorbent material and then heated the mixture with microwaves. This new, more efficient process converted nearly 90 percent of the waste oil sample into usable fuel.
“Our results indicate that a microwave-heated process shows exceptional promise as a means for recycling problematic waste oil for use as fuel,” Chase and Lam said. “The recovery of valuable oils using this process shows advantage over traditional processes for oil recycling and suggests excellent potential for scaling the process to the commercial level.”
Image: Matthias Kulka/Corbis