Start Date: Sep 02, 2008
End Date: Sep 01, 2013
Design and fabricate equipment for field-fractionation of bioenergy crops during harvest. Test equipment on established fields of alfalfa, switchgrass, and reed canarygrass. Determine yield and quality of fractions obtained, along with power requirements and operating costs. Improve design of equipment to improve performance, reliability, and operating costs. Store harvested materials under different conditions, and determine dry matter losses and quality changes resulting from storage under these methods. We will also compare the yield and quality of switchgrass and reed canarygrass when stored at different moisture levels in either bag silos (a widely adopted storage technology) or in bunker silos (a potentially lower-cost method that does not generate plastic waste). Conventional measures of silage preparation (packing density, porosity, temperature profiles) will be combined with measures of microbial conversion in the silo (fermentation acid production), and of subsequent bioconversion potential of feedstock after storage to fuels and fuel precursors. Because exposure of anaerobically stored feedstocks to air can cause undesirable spoilage by microorganisms, we will conduct aerobic stability tests to determine if storage method affects the rate and extent of feedstock spoilage, and if different microbial agents are responsible for spoilage of different feedstocks stored under different conditions. We will estimate costs of storage of each feedstock that will take into account the dry matter losses and quality change of each feedstock during storage, and the bioconversion potential after storage.