Anaheim, California – Researchers in England have developed a process with the potential to recycle used motor oil into a gasoline-like fuel using microwaves. The research was presented at the 21st national meeting of the American Chemical Society.

“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.”

An estimated eight billion gallons of used motor oil are removed during oil changes in cars and trucks each year worldwide. In some countries, including the U.S., some of that dirty oil is collected and re-refined into new oil, or processed and burned in special furnaces to heat buildings. Chase noted that such uses are far from ideal, due to concerns over environmental pollution. In many other countries, used oil is discarded or burned in ways that can pollute the environment.

Among the most promising recycling techniques is pyrolysis, which involves heating oil at high temperatures in the absence of oxygen. This breaks down the oil into a mix of gases, liquids and solids, some of which can be chemically converted into gasoline or diesel fuel. However, the process heats the oil unevenly, producing gases and liquids that are not easily converted into fuel.

Chase said that the new method overcomes the problem and uses a new pyrolysis technology. The waste oil is mixed with a highly microwave-absorbent material and then heated with microwaves. The process converts nearly 90 per cent of the waste oil sample into fuel, and scientists have used the process to produce a mixture of conventional gasoline and diesel.

“Our results indicate that a microwave-heated process shows exceptional promise as a means for recycling problematic waste oil for use as fuel,” Chase 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.”

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