Lancaster University Develops Method to Easily Turn Spent Old Coffee Grounds into Biofuels

Spent coffee grounds, which have a high calorific value, offer a good low-cost alternative feedstock. However, most used coffee grounds are currently just dumped. In 2014, more than 9 million tons of spent coffee grounds were discarded. Researchers at Lancaster University found a way to significantly improve the efficiency of the process of using spent coffee grounds for biofuel production.

Traditionally, manufacturers mix spent coffee grounds with hexane and cook the mixture at 60°C for between 1-2 hours. The hexane is then evaporated, leaving behind the oils. Methanol and a catalyst is then added to make biodiesel, and a glycerol by-product. The research team has consolidated the existing multi-stage process into one step, in-situ transesterification, which combines extraction of the oils from the spent coffee grounds and the conversion of it into biodiesel.

Lancaster University researchers, led by Dr. Vesna Najdanovic-Visak, combined the processes by using just methanol and a catalyst in only 10 minutes, a significant reduction in time needed and associated energy costs. The process can potentially produce 720,000 tons of biodiesel each year from spent coffee grounds.