Thermokinetic Characteristics of Coal Combustion under High Temperatures and Oxygen–Limited Atmospheres

Abstract

ABSTRACT Coal fires are widespread in the coal–major producing countries, which causes serious environmental issues due to the high temperature and hazardous gases during coal combustion. Under oxygen–depleted atmospheres, the thermal behaviors and kinetic characteristics during coal combustion at high temperatures were paid more attention by the method of TG–DSC synchronous thermal analysis. The results indicate that the focused weightlessness and heat release processes became scattered under oxygen–depleted atmospheres, and the influence of oxygen concentration obviously increased when it was below 13 vol.%. The mass presented a linear correlation to the quantity of heat release, and the relationship between the mass and quantity of heat release showed stage characteristics with oxygen concentration. Moreover, the kinetic modes transformed from random nucleation and subsequent growth to contractive sphere, and the critical oxygen concentrations are consistent to these of thermal behaviors. These findings are significant for better understanding the characteristics of coal spontaneous combustion at high-temperature and under low-oxygen concentrations.