Adiabatic spontaneous coal combustion period derived from the thermal effect of spontaneous combustion

We propose a method for measuring the thermal effect of spontaneous combustion and the adiabatic spontaneous combustion period of coal based on the coupled thermal effects of coal and oxygen. A physical similarity reference test system was established by combining the characteristics of the thermal analyses. Using this system, coal samples from the main coal seam of the Zhao Xian mine, which has high propensity for spontaneous combustion, were tested and analyzed. The adiabatic spontaneous com-bustion period for coal was determined by curve fitting. Based on the heat equation, the adiabatic spontaneous combustion period for coal from the Zhao Xian coal mine was determined to be 95.9 h. Mutual verification among the adiabatic spontaneous combustion periods of coal was achieved through the same fitting procedure. The error between the two experimental results was less than 0.22 % with 0.01 variance, which proves that the experimental approach is applicable for calculating the adiabatic spontaneous combustion period of the Zhao Xian coal sample. Our results should facilitate theoretical and experimental evaluations of the likelihood of spontaneous coal combustion and its associated risks. (c) 2021 Elsevier Ltd. All rights reserved.