Suspension-firing of biomass for heat and power generation: The perspectives of a closed model for non-spherical particle tracking

Abstract

Co-firing biomass in existing utility boilers can substantially increase the use of renewable energy sources and reduce CO2 emissions. Compared to pulverized coal particles, biomass particles prepared for suspension-firing are often large and highly non-spherical, resulting in very different particle motion and combustion performance. This paper presents a unique closed model for non-spherical particle motion, applicable to biomass suspension-firing simulation. Different from the conventional particle tracking model, the closed model solves the coupled equations of translational and rotational motion of non-spherical particles and fully addresses the effects of particle shape and orientation. The new model is able to accurately reproduce the experimental results in both translation and rotation of cylindrical particles. After experimental validation, the new model is unprecedentedly and successfully used in simulation of industrial biomass suspension-firing processes. To further improve the accuracy and applicability of the model for the current biomass suspension-firing, the latest achievements in force and torque coefficient correlations for non-spherical particles will be integrated and more relevant testing of pneumatic transport of biomass particles will be done to collect data for further model validation.