The temperature rise characteristics of coal during the spontaneous combustion latency

Abstract

The spontaneous combustion latency is the initial stage of coal spontaneous combustion and provides the primitive thermal resource for it. Study on this process is of great significance for research on the mechanism of coal spontaneous combustion. An E-type thermopile was used to study the temperature rise characteristics of coal during the spontaneous combustion latency. The dependency relationship between the temperature rise characteristics and time was discussed under the condition of different coal samples and oxidation temperatures. The evolution of active groups from 30 °C to 70 °C was investigated by means of in suit Fourier transform infrared spectroscopy (FTIR). The relationship between the temperature rise characteristics and active groups of coal was studied. The results reveal that the temperature rise characteristics of coal are controlled by the combined effects of the metamorphic degree and oxidation temperature. The maximum temperature rise of LJ coal during the spontaneous combustion latency is 0.97 ℃. The changes of active groups differ from each other, which depend on the reactive activity and oxidation temperature. Carbonyl group, carboxyl group and -C=C- group appear to be the primary groups responsible for the heat generation of the coal during the spontaneous combustion latency. The results will contribute to further understanding of the mechanism of spontaneous combustion of coal.