Roasting biomass may be key process in bioenergy economy

PhysOrg.com

February 23, 2010 (PhysOrg.com) -- Biorefineries may soon rely on a process akin to roasting coffee beans to get more energy-dense biomass.

A new collaborative study between Idaho National Laboratory and Pacific Northwest National Laboratory (PNNL) will investigate whether such roasting can create a more valuable product for the nascent biofuels industry. Initial studies show that driving moisture and volatile compounds from wood or straw could make the biomass more stable, compactable and energy dense.

"This could cut a lot of costs by providing a less expensive and higher-value product," said INL biofuels researcher Christopher Wright. "This technology has the ability to overcome biomass's moisture, mass and energy density problems, which make up a huge proportion of the cost barriers."

The technology he refers to is called "torrefaction" — heating biomass above 250 degrees Celsius in an oxygen-free environment. "It's not very different from roasting coffee beans," said Wright. But while coffee beans are roasted for flavor, biomass could be "torrefied" simply to improve its physical characteristics.

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