Low Energy Rotary Shear for Submillimeter Particle Production

Second generation biorefiners must be able to accept and process the full range of regionally relevant biomass sources, including hardwoods, softwoods, and a rapidly expanding number of herbaceous species (corn, miscanthus, switchgrass, sorghum, etc). Comminution technologies are needed that can process dry, green, and high moisture baled herbaceous biomass into millimeterscale feedstock particles. In addition, systems to feed biomass into comminution equipment need to accommodate bulk field chopped biomass, round bales, and large rectangular bales. This project will develop a low energy rotary shear comminution system to make millimeterscale particles for use in biochemical and thermochemical conversion platforms. In the DOE SBIR Phase I and II projects, we demonstrated the technical feasibility of a paradigmchanging rotary shearing comminution technology that enables efficient milling of high moisture and green biomass all the way to final millimeterscale particle size BEFORE drying when drying is needed and WITHOUT drying when high moisture feedstocks are desired. The new rotary shearing technology is an alternative to conventional hammermills for preprocessing wood chips and debaled herbaceous biomass into feedstocks for conversion to biofuels, biochemicals, and bioproducts. Phase I and II results demonstrate that the proposed rotary shearing technology can produce similar particle sizes to a hammermill on high moisture feedstocks, but with higher flowability and with a fraction of the comminution energy. Our Phase IIB project will entail design, building, and testing of a commercialscale and quality rotaryshearing comminution system having a design capacity of 7.5 tons per hour with wood chips and at least 5 tons per hour with lowerdensity herbaceous materials. The comminution system will be designed in cooperation with launch customers and production tested at their facilities. Additional specification support will be provided by national laboratory to ensure the equipment can be integrated into their user facility for testing in direct comparison with the industry standard debaler and commercialscale hammermill. Process economics will be evaluated against the DOE base cases for each feedstock and conversion pathway. Commercial deployment of rotaryshearing biomass comminution systems will improve the net energy balance of cellulosic biofuels and bioproducts, thus reducing the contribution of these industries to greenhouse gas emissions. This technology enables processing of high moisture and “wet bale” biomass to increase utilization of available biomass resources and reduce process wastes. Key Words: biofuel, biomass, biorefinery, feedstock, size reduction. Advanced rotary shear technologies from this project will reduce the cost of reactorready feedstocks and improve the energy balance for advanced biofuels, thus moving the nation towards import oil independence.