Single particle char combustion and gasification

Abstract

A comprehensive mathematical model is developed to predict the gasification behavior of coal-derived char particles when contacted with a gaseous mixture containing seven species at known temperature and composition. Various physical, chemical and transport effects are incorporated into the transient mass and energy balances inside the porous particle as well as in the surrounding gaseous phase. Significant ignition and quenching phenomena are predicted at the reaction conditions of practical interest, especially in the oxygen rich environment. Consequently, substantial differences in the burn-off rates and overall gasification behavior are observed over a narrow range of ambient temperatures. Such phenomena indicate the need to develop detailed heterogeneous reactor models for the reliable design and operation of commercial gasifiers. © 1989.