Coffee grounds for biodiesel

art technia
By Yun Xie Published: November 25, 2008 - 01:36PM CT

Used coffee grounds may be garbage to most of us but, to chemical engineers at University of Nevada, they are a versatile source of green energy. Narasimharao Kondamudi, Susanta Mohapatra, and Mano Misra proposed that the solid waste from coffee brewing can do a lot more than act as compost for gardens. They set out to see if they could extract oils from old coffee grounds and chemically convert those oils to biodiesel.

Spent coffee grounds are about 15 percent oil, which is only slightly less than many of the other biodiesel feedstocks. Since the world produces over 16 billion pounds of coffee per year, there is a constant and cheap supply of solid coffee waste. Kondamudi, Mohapatra, and Misra also predict that biodiesel from coffee grounds would be more stable than those from other sources because coffee contains antioxidants that would slow down degradation.

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