Influence of Air Leakage on the Risk of Spontaneous Combustion in Close Coal Seam Groups

To study the effect of air leakage on the risk of spontaneous combustion of close coal seam clusters, the heat release characteristics and microstructural evolution of coal samples during primary and secondary oxidation at different air volumes were compared with the help of a high precision calorimeter and an X-ray diffractometer. The Arrhenius formula was applied to calculate the effect of different air volumes on the activation energy. The results show that: The effect of air volume on coal spontaneous combustion is found to have stage adaptation, low airflow is more conducive to coal self-ignition in the pre-heat storage, and the effect of high air volume on coal spontaneous combustion becomes increasingly significant after the temperature rises to a certain degree. The effect of air volume on secondary oxidation and primary oxidation has high affinity. The risk of spontaneous combustion of secondary versus primary oxidation is not absolute, but there is a critical temperature, and secondary oxidation has a higher risk of spontaneous combustion only when the temperature is higher than the critical temperature. The effect of wind volume on the morphological characteristics of the aromatic layer structural unit is achieved mainly by changing the side chain structure.