Macrocharacteristics of gaseous indicator products and exothermicity during low-temperature oxidation of samples from different regions of the same coal seam from Huainan, Anhui, China

To study the similarities and differences in the macrocharacteristics of a coal seam during low-temperature oxidation at different regions of the same coal mine, six coal samples from the 13-1 seam were selected from Huainan, Anhui, China. The macroscopic spontaneous combustion characteristics, including the gaseous products and characteristic temperatures, during the low-temperature oxidation of samples from different regions of the same coal seam, were studied using a temperature-programmed test. The results revealed that the characteristic temperatures of the samples from the coal seam were close to each other, the critical temperature range was 70–80 °C, and the crack temperature range was 90–100 °C. The CO/O 2 ratio varied considerably. Thus, the degree of incomplete oxidation reaction to release CO was different at different regions in the coal seam. Moreover, the variation in the CO/CO 2 ratio of the samples from the coal seam was similar. A calorimeter (C80 Calvet, SETARAM, France) was adopted to explore the exothermic characteristics of the coal seam during low-temperature oxidation. The exothermic onset temperature of the samples from the coal seam was similar, with a range of 50.1–54.3 °C. Differences were observed in the total thermal energy released by oxidation at low temperature in the samples from the coal seam; however, the percentage of thermal energy release at low temperature and that during the entire oxidation process was similar. The changes in the apparent activation energy of coal specimens from the seam were similar. It was, and is, important to investigate the prediction and prevention technique of spontaneous combustion in regional coal seams.