Roasting Biofuel Crops Like Coffee Beans Could Boost Energy Yield by 20%
Two British engineers have discovered a novel technique that could help make biofuel production cheaper and boost the energy content of some crops by up to 20%. The process, called "torrefaction," consists of slowly heating biomass in an inert atmosphere to a temperature of 300°C; it yields a solid product with a lower moisture content, minimizing transportation and storage issues.
While it's more commonly associated with coffee production, Jenny Jones and Toby Bridgeman of the University of Leeds, who led the study, published in the journal Fuel, think it'll work in a cinch for biofuel production too. They specifically tested willow, canary grass and agricultural residue wheat grass -- crops often used in the U.K. -- to see what happened when they went through torrefaction and how they performed as biofuels.Not only did the treated biomass take less time to heat up, but it also provided higher energy yields upon combustion. Other benefits include less smoke formed during the combustion process, higher density and similar mechanical strength to the initial biomass and better stability.
Willow came out on top in the trials, boasting a 86% energy yield; by comparison, wheat straw and reed canary grass had energy yields of 77% and 78%, respectively.
Image courtesy of FreeWine via flickr