Combined Drying and Grinding of Biomass in One Operation

72540B03-I Many kinds of biomass can be used as fuel or fertilizer after being dried and ground. Combining drying with grinding in one operation would provide simplicity and offer better drying efficiencies. This project will use centrifugal force for grinding, and energy from the grinding process will be used for drying, thereby obviating the need for an external heat source and resulting in higher energy efficiencies than any other process. Phase I will determine the optimum design parameters for the combined machine and predict its performance. In particular, Phase I will: (1) study the effect of additional external heat input into the machine, (2) quantify the aerodynamic drag of the blades, (3) determine the rate of recirculation of the drying air, (4) quantify the extent of drying in different parts of the machine, and (5) perform modeling and analysis. In Phase II, an optimized machine will be field tested, especially with respect to the grinding and drying of crop residue and grasses. Commercial Applications and Other Benefits as described by awardee: Both the agricultural sector and the paper industry should benefit from this process. At present, animal manures are applied directly to the land as fertilizer, causing E. coli contamination, greenhouse gas emissions, and eutrophication. The energy-efficient process should make the drying and grinding of animal manures into fertilizer cost-competitive, while also eliminating pathogens and avoiding the problems caused by direct land application. When applied to paper sludge, it should reduce landfill volumes.