Comprehensive Study of Ignition and Combustion of Single Wooden Particles

Abstract

How quickly large biomass particles can ignite and burn out when transported into a pulverized-fuel (pf) furnace and suddenly exposed to a hot gas flow containing oxygen is very important in biomass cofiring design and optimization. In this paper, the ignition and burnout of the largest possible biomass (pine wood) particles in a pf furnace (a few millimeters in diameter) are studied experimentally in a single particle combustion reactor rig, in which the ambient gas temperature and oxygen concentration can vary in the ranges 1473–1873 K and 5–20%, respectively. A one dimensional (1D) transient model is also developed to predict their conversion, in which the key processes inside the particle and in the boundary layer outside the particle are properly considered. For the pine wood particles in which large temperature gradients exist, the primary heterogeneous ignition is always detected for all the test conditions. As the particle is further heated and the volume-weighted average temperature reaches the o...