Coal Combustion Characteristic and Its Structural Evolution under Oxy-Fuel and Air Environment

In this paper, two typical Chinese coals were selected to investigate the pulverized coal combustion characteristic and their pore structure evolution in oxy-fuel combustion and conventional air combustion environment with a drop tube furnace (DTF). Results show that the burn-off rate of pulverized coal in O₂/CO₂ mixtures is lower than that in O₂/N₂ environment with equivalent oxygen concentration. The Oxy-Fuel chars show smaller porosity parameters such as specific surface area (S_BET); specific pore volume (V_BJH) and average pore diameter (d_Pore) than those of chars obtained in O₂/N₂ environment. Morphology analyses also present the same results and agree well with those determined by N₂ adsorption method. The present results might have important implications for further understanding the intrinsic kinetics of pulverized coal combustion in O₂/CO₂ environment.