Analysis of the compound effect of mine water on coal spontaneous combustion and its application in coal fire...

The research on mine fire control has confirmed that the probability of CSC (Coal Spontaneous Combustion) after mine water treatment is higher than raw coal (RC). However, the current research on the effect of mine water on CSC is sketchy, which is not close to real water environment of the mine, and there is a lack of in-depth and systematic discussion on the compound effect of the characteristic components of mine water on the process of CSC. According to the actual mine environment, this paper prepared samples soaked by different types of mine water under different conditions, then the compound effect of mine water on CSC is studied by means of thermogravimetric, infrared and gas analysis. The results show that the characteristic temperature point T1 of coal samples after mine water treatment increases significantly, with a maximum increase of 11 °C, while T2-T4 decreases to different degrees, with a maximum decrease of 13 °C. The maximum apparent activation energy decreased by 32 %, which decreased by 40.6KJ/mol. The release of CO and CO2 is 1-2 times that of raw coal. The content of organic functional groups is 1.1-1.8 times higher than that of raw coal. The changes of these parameters are enhanced with the increase of acidity of mine water, which indicates that mine water can promote the spontaneous combustion activity of coal. The promoting effect mainly comes from the swelling effect of water, and the inhibiting effect is mainly related to the inorganic salts in mine water, but the inorganic salts contained in the mine water are not enough to reach the concentration that can inhibit CSC, so the overall performance of mine water is to promote the CSC. This study is conducive to understanding the influence mechanism of actual mine water environment on CSC, and provides a theoretical support for control of CSC and comprehensive utilization of mine water.