Spinning straw into gold is close to reality for some farmers pursuing alternative energy to support their operations. Converting biomass to energy is an obvious solution for farmers who have resources such as crop salvage readily available to fuel their power needs. In the Pacific Northwest, grass seed farmers are annually left with more than one million tons of straw from which they realize little income by selling it as animal feed. A much greater profit can come from utilizing this biomass onsite for power generation.
In a research project jointly sponsored by the U.S. Department of Energy (DOE) and the U.S. Department of Agriculture (USDA), WRI designed and fabricated a bench-scale dual bed gasification unit to determine the preliminary feasibility of a novel process specifically designed for the low-cost conversion of biomass or sub-bituminous coal into high-quality synthesis gas suitable in the near-term for stationary power generation and ultimately for the production of liquid fuels. To develop this highly efficient gasification process, WRI’s staff characterized the synthesis gas product and optimized operating conditions and configuration of the gasification unit. WRI’s unit was designed to run at atmospheric pressure and employ a solids-circulation type oxidation/reduction cycle that is significantly different from traditional fluidized-bed or up-draft type gasification reactors. Test data was applied to a preliminary design and cost estimate for a 1 ton / hr pilot-scale unit appropriate for farm-scale applications.
In 2006, this gasifier designed and built by WRI was dismantled and shipped to a grass seed farm located in Spokane County, Washington. Reassembly of the gasifier at the farm and initial shakedown was completed in late 2007. Under supervision from the USDA Agricultural Research Service (ARS) in Corvallis, Oregon, it now serves as an active pilot project demonstrating the low-cost conversion of straw biomass where the produced synthesis gas is being used to generate electricity using a 300 kW reciprocating engine/generator.