Pyrolysis and volatile combustion of a single large lignite particle

A model for the evolution and combustion of volatiles from a single large lignite particle in a hot oxidizing gas stream is proposed. The analysis is divided into preignition and postignition stages. The transfer of heat both to and through the particle, as well as multireaction pyrolysis kinetics, are considered in order to find the overall devolatilization rate. The model also includes allowance for the effects of volatile species on the flame temperature. Predictions of transient weight, ignition and extinction time delay for a flame supported by the volatiles are in good agreement with the experiments.