The Last Straw? Making Gas From Crop ResidueBy Laura McGinnis
August 31, 2006
Illegal to burn and expensive to move, straw creates serious disposal problems for the grass seed industry. Thats why two Agricultural Research Service (ARS) labs are collaborating with scientists from the Laramie, Wyo., Western Research Institute to develop a small-scale gasification reactor.
The Pacific Northwest grass seed industry that provides seed for lush lawns for homes, parks and golf courses also produces millions of tons of straw every year, only a fraction of which can be used as mulch for conservation.
ARS researchers at the Forage Seed and Cereal Laboratory in Corvallis, Ore., and the Crop Conversion Science and Engineering Laboratory in Wyndmoor, Pa., are developing technology for converting that straw into synthetic gas that can be used to produce electricity or liquid fuel.
Within the prototype reactor, straw is reduced to charsmall particles of carbon and residueand converted into a mixture of vaporized gases that can be used to produce liquid, synthetic gas.
The scientists believe the research will enable them eventually to develop an economically feasible method to dispose of straw because it eliminates the expense of transporting straw off property.
The technology is still undergoing trials to improve its effectiveness and economy. ARS chemical engineer Akwasi Boateng, at Wyndmoor, and plant physiologist Gary Banowetz, at Corvallis, believe that in the near future, the small-scale gasification system will provide not only an environmentally beneficial alternative to field-burning grass straw, but an economically competitive alternative to fossil fuel-derived energy.
Based on the carbon content of straw, Banowetz estimates that synthetic gas produced in the reactor could be converted into about 60 gallons of fuel per ton of straw. With 7 million tons of excess grass and cereal straw generated each year, the Pacific Northwest has the potential to produce 420 million gallons of liquid fuel.
ARS is the U.S. Department of Agriculture's chief scientific research agency.