Grant: Discovery Grants Program - Individual

LITERATURE A pelletized biomass flows like a grain, and as such biomass can benefit from an already well-developed grain handling technologies. However, biomass pellets are more prone to damage than grains. Biomass pellets tend to disintegrate when accidentally get wet with liquid water or expose to humid air. Moisture sorption and auto oxidation are two processes responsible for self-heating of pellets. The available literature does not address adequately the process of heat accumulation in bulk pellets. PROGRESS My discovery research to date has led to the application of thermal pre-treatment to lessen the variability in biomass as a feedstock. A lower variability in biomass properties leads to an increased feedstock sources available to the industry. My logistics modeling approach has shown the logistical advantages of pellets over other forms of solid biomass like wood chips. I have also quantified the critical concentration of toxic gasses with respect to toxicity to human. The pellet industry has developed best practices to minimize potential harm to people working around stores. OBJECTIVES AND METHODOLOGY This research is a continuation of my long-term goal in developing optimal designs for converting raw biomass to usable feedstock. The scope of operations include size reduction, drying, and feedstock densification. The present research investigates the conditions that initiate self-heating and the ensuing factors that propagate heat within a pile of pellets. The proposed approach uses experimental data (gas concentration, temperature, vapor pressure, pellet swelling) to develop mathematical models. The models will be used for design and management of stored pellets. This research will create new and relevant knowledge for the bioenergy community and will serve to encourage further scholarly inquiries among current and future students and researchers. HQP This research engages one Ph.D. plus two M.Sc. students, and five undergraduate students, one per year. I am committed to hiring and training a diverse qualified HQP's. The Ph.D. will develop the heat/gas/vapor flow models. M.Sc.1 develops kinetics of heat of sorption for pellets. M.Sc. 2 develops kinetics of swelling and the resulting internal pressures. The undergraduates plan instrumentation, collect and analyze data on pellets produced on the new CFI funded laboratory pellet mill. IMPACT Self-heating and off-gassing are the two major causes of fires in confined spaces. The Canadian wood industry has experienced a number of fires, a few with fatalities. Unlike for grain stores, ventilation of stored pellets with air is not a safe practice for biomass pellets. The oxygen and water vapor in the ventilating air promote self-heating. To date, the complex processes involved in self heat have not been demonstrated clearly to the industry. My proposed research plans to do that. The wood- and in future the ag-pellet industry would contribute significantly to the Canada's rural economy.