Experimental study on the risk of secondary oxidation spontaneous combustion of water immersed coal

In order to study the spontaneous combustion risk in the whole process of secondary oxidation heating and cooling of water immersed coal, the spontaneous combustion characteristic parameters of primary and secondary oxidation heating and cooling of raw coal and water immersed coal were compared by means of temperature programmed experiment.By using the apparent activation energy calculation model, the apparent activation energy of different temperature stage was calculated by linear fitting method in rectangular coordinates. The experimental results show that the oxygen consumption rate, the rate of spontaneous combustion characteristic gas production and the ultimate heat release intensity of the coal sample in the whole process of temperature rise and temperature drop after the dry-cracking temperature meet the requirements of the law that the water immersed coal is higher than the corresponding raw coal, and the secondary oxidation is higher than the corresponding primary oxidation; in terms of apparent activation energy, water immersed coal is lower than the corresponding raw coal, and secondary oxidation is lower than the corresponding primary oxidation.Therefore, the danger of spontaneous combustion of water immersed coal is greater.