The Effect of Heat Transfer on Coal Devolatilization

This study investigates the heat transfer effect on the transient behavior of preheating, ignition, and combustion of a single coal particle pyrolyzed in a hot convective environment. The theoretical model covers two aspects: (1) heat and mass transfer and pyrolysis within the particle, (2) thermal radiation, diffusion, and combustion of the reactive gases and air outside of the particle. Semenov’s criteria are adopted to define ignition and a modified model derived from droplet combustion is used to estimate the flame radius and temperature. Distributions of temperature, species concentrations, and combustion rate are solved simultaneously. The prediction is verified by a set of experimental data.