Combustion Modelling of Pulverized Biomass Particles at High Temperatures

Biomass co-firing is becoming a promising solution to reduce CO2 emissions, due to its renewability and carbon neutrality. Biomass normally has high moisture and volatile contents, complicating its combustion behaviour, which is significantly different from that of coal. A computational fluid dynamics (CFD) combustion model of a single biomass particle is developed in this work, to predict the mass loss properties and temperature profile during the biomass devolatilization and combustion processes, by solving the energy and mass transport equations. The biomass devolatilization reaction was simulated by a two-competing-rate model and the biomass char burnout rate was controlled by both kinetics and diffusion to predict the particle size changes. The resulting predicted temperature profiles show good agreement with experimental data. The results also shed light on the effects of biomass particle size, air temperature and oxygen concentrations on biomass particle combustion behaviour.