Effect of the heating rate on the spontaneous combustion characteristics and exothermic phenomena of weakly caking coal at the low-temperature oxidation stage

Abstract

The low-temperature oxidation stage of coal spontaneous combustion (CSC) is crucial due to its impact on likelihood of spontaneous fire, as well as fire prevention in coal storage and underground mine environments. A detailed understanding of the oxidation characteristics of coal can provide a systematic understanding of CSC. A temperature-programmed experiment was conducted to simulate CSC in its low-temperature oxidation stage under different heating rates. The characteristic temperatures and oxidation performance were calculated using related functions, and the temperature distribution in space was obtained using three different measuring points. An additional experiment using a C80 micro-calorimeter was also performed to examine the heat flows. The coal sample was subjected to different heating rates, and variations in endothermic and exothermic heats were recorded using the derivative of the heat flow concerning time (dHFCT). A low heating rate promoted the exothermic effects of coal oxidation, resulting in a more thorough exothermic process.