Study on the oxidation thermal kinetics of the spontaneous combustion characteristics of water-immersed coal

Abstract Water-immersed coal is more likely to spontaneously combust than raw coal. To investigate their differences from the perspective of thermal kinetics, thermogravimetric experiments were conducted with water-immersed coal and raw coal. Thermodynamic parameters were calculated and compared with five different kinetic analysis methods. Results showed that the activation energies of water-immersed coal obtained by five methods were all reduced by more than 19% than those of raw coal. It indicated that the energy required for the self-heating and spontaneous combustion of water-immersed coal was remarkably lower than that of raw coal. This observation was the dynamic reason why water-immersed coal was more likely to spontaneously combust than raw coal. In addition, among these kinetic methods, the Kissinger-Akahira-Sunose (KAS) method is more accurate and is highly recommended. This research provides better understanding of the spontaneous combustion mechanism of water-immersed coal and allows for kinetic parameters to be calculated more accurately.