Preheating of Cold, High Moisture Particulate Biomaterials to Reduce Drying Time
Forest Concepts led a two-year project to reduce fossil fuel consumption and improve the energy efficiency of dryers through the application of radio frequency (RF) energy impartation to preheat cold-wet bulk particulate biomass materials. A comprehensive biomass heating and drying mathematical model was developed that enables simulation of drying systems for biomass as well as most other bulk porous particulate materials. Experimental and modeling results conclude that energy consumption for both RF preheating and hot-air preheating are essentially equal for cold, high-moisture feedstocks that are above fiber saturation and therefore not economically beneficial for those conditions. Further results suggest that RF heating may have a direct energy consumption benefit in the late stages of drying and in case of preheating biomass that has a moisture content below fiber saturation. This work was funded in part by the US Department of Energy under contact DE-EE0009130.