March 12, 2008

Trash = Electricity

The Army is sending two, 4-ton biomass refineries to Iraq.  I first heard about these biomass refineries in the aftermath of Katrina, where all of the garbage could be put into the biomass refinery and it consumes the trash and puts out electricity.

In 2006, the Army commissioned Defense Life Sciences, Purdue biomass experts and three other companies to build a prototype refinery. An updated version completed last year at a cost of about $1 million now sits in an unheated warehouse on Purdue's West Lafayette campus awaiting a final shakedown before deployment. The same team is currently building the second unit.

Nate Mosier, an assistant professor of agricultural and biological engineering who is overseeing the work at Purdue, said the refineries are unique in their ability to burn multiple fuels at once. They're also portable, designed to fit snugly into a standard shipping container.

The trash-to-energy process begins when unfiltered garbage is fed into a chute, falling into a grinder that chews the trash into small pieces.

Organic food waste heads to a bioreactor where an industrial fermenting process produces ethanol. In another chamber, plastic, cardboard and other trash items are heated to create low-grade propane or methane.

Those gases and the ethanol are then combusted in the refinery's modified diesel engine, which powers a 60-kilowatt generator.

About 10 percent of the electricity the refineries produce are used for the machines' power needs, but the remaining 90 percent would be available for the troops.

Beyond the military applications, the refineries could provide temporary power after natural disasters. Mosier said they could be set up near hospitals or shelters to supply power and light, while feeding off the trash those locations produce.

In our throw-away society, these machines should be mass produced on a smaller scale, be plugged into the power grid and reside on every street corner of America.

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