New work from the United States Department of Agriculture could someday help cars run like greased lightning, powered by biodiesel made from restaurant grease.
Mike Haas, a chemist at the department’s Agricultural Research Service in Pennsylvania, is working with the Philadelphia Fry-o-Diesel company to demonstrate that trap grease, which restaurants and food companies collect from their drains, can be converted into a clean-burning, renewable fuel source.
Trap grease is unmarketable. According to the company, restaurants in southeastern Pennsylvania and New Jersey collect more than two million gallons of trap grease every month that must be removed at a cost of about five cents per gallon. Illegal disposal and sloppy collection can lead to clogged sewers and polluted water.
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Haas hopes to demonstrate trap grease’s potential as a marketable biodiesel feedstock. He and co-worker Karen Scott helped characterize trap grease samples, advised the company on operation design and analyzed the products of trial runs as they improved the chemistry needed to produce biodiesel.
The scientists remove water and solids from the trap grease, then process the feedstock to produce biodiesel. Initial small-scale operations have successfully produced fatty acid methyl esters from trap grease. The esters will be tested to determine whether they meet accepted biodiesel standards.
One challenge right now is economic. Removing impurities from trap grease is expensive, but as the cost of petroleum-based diesel rises, it’s becoming competitive.
If successful, this research could solve many problems. Giving trap grease a new purpose would reduce waste and create a new market. Illegal disposal would decrease, leading to improved water quality. Cleaner-burning diesel fuels would improve air quality.
