Modeling the Vaporization of Inorganic Matter from a Single Coal Char Particle Burning in an O2/CO2 Atmosphere

Abstract

The present work aims to model ash vaporization from a burning char particle during pulverized coal combustion in an oxygen-enriched O2/CO2 atmosphere. The modeling development was to apply the classic ash vaporization model of Quann and Sarofim to cover oxy-coal combustion over a wide range of O2 concentrations by coupling it with the double-film char burning submodel to properly describe the burning process of a single char particle. The model was extensively validated with literature data on the vaporization of SiO2, MgO, and CaO in both O2/N2 and O2/CO2 atmospheres. The model was proved to be able to predict the vaporization behavior of SiO2 during char conversion stages in both atmospheres, covering the effects of coal type, particle size, and O2 concentration. The model predicts the vaporization of MgO and CaO during char combustion of bituminous coal, but improvement is required to describe the vaporization of MgO and CaO during char combustion of lower-rank coals by considering the occurrence of M...