Particle-Level Densification of Bulk Biomass Materials to Replace Pelletized Fuels and Feedstocks

C58-13b-281550-Abstract Pellets are an important commodity as an export and feedstock for renewable energy production, both locally for heat and globally for power. Additionally, there is a new emerging set of users for pelleted feedstocks in the advanced biofuels and biochemicals arena that are explicitly specifying pellets to take advantage of high particle density, high thermal conductivity/low porosity, and higher surface area per unit bulk volume. However, the process of creating these high-density pellets is energy intensive and expensive. Converters desire the particle-level properties of deconstructed pellets, but at a lower cost and with less equipment at the front end of their biorefineries. Thus, there is tremendous opportunity to change particle morphology (shape) and particle porosity through compression to increase bulk density using new particle-specific processing methods. To date, it is unclear what the optimal process parameters are that maintain flowability characteristics of the bulk biomass as well as comparable bulk densities to pellets without the energy consumption of drying, undersized grinding, and recompression into larger particles. This project creates a rigorous pathway to answer key science and engineering questions to develop an optimal particle-level densification process. This will be accomplished in part through the development of a lab-scale apparatus in phase 1 to measure forces and energy consumption for continuous crushing of particulate biomass under various conditions. Phase II will use the Phase 1 data set to develop and optimal pilot scale (approximately 1 ton per hour) machine for light-commercial validation and demonstration of the technology. Phase III will focus on the deployment at full commercial scale (approximately 10 tons per hour) of the technology. The proposed technology may open additional markets for domestic wood fuel producers, enabling community-scale biomass processing centers to provide lower-cost wood fuels to local disadvantaged consumers. If 10% of the US pellet market adopts the new technologies, then a total of 185 million kwh (combined electrical and natural gas sources) will be saved annually. The new technologies remove the drying component of pellet production, potentially reducing carbon emissions by 29,000 metric tons (Mg) per year, contributing to cleaner energy production.