Modified Discrete Random Pore Model Considering Pore Structure Evolution to Depict Coal Chars Combustion in O2/CO2

Abstract

The O2/CO2 combustion of coal chars currently considered as one of the promising technologies has a remarkable effect on reducing greenhouse gas emissions, and it is of importance to investigate the mathematical model of pore evolution at char reaction process, while discrete random pore model (DRPM) can be usually considered as the mathematic modeling of pore evolution for effective prediction of char combustion at O2/CO2. In this work, pore structure variation of three chars during reaction at O2/CO2 were presented by the N2 isothermal adsorption/desorption method. The universally used assumption of proportional relation of superficial area and combustion rate was improved for application to coal chars, indicating true superficial area associated with the reaction rate should be corresponding to the pore superficial area 2πl(r0 + θΔr/2). Therefore, a new pore structure model (MDRPM) was created to simulate carbon conversion of three coals combustion process in O2/CO2 when chemical reaction is considered...