Experimental Study on the Inhibition Effect of the Inhibitor on Coal Spontaneous Combustion Under Critical Temperature

At present, related research on inhibitors has been gradually improved, but there is still a lack of research on the inhibition characteristics at specific release temperatures and the mechanism of inhibiting coal spontaneous combustion. Based on this, In this study, the inhibition characteristics of adding inhibitor to coal under critical temperature (R70) are studied in depth. In the experiment, lignite was selected as the research object, and four different types of inhibitors, MgCl2, triphenyl phosphite (TPPI), Phytic acid (PA), and melatonin, were applied to coal samples at room temperature and 70 °C, respectively. The temperature-programmed-gas chromatography test and Fourier infrared spectroscopy experiment were carried out, and the oxidation kinetic parameters were calculated to study the oxidation characteristics and micromechanism of the coal samples in the process of spontaneous combustion. The experimental results show that the amount of CO gas release and oxygen consumption rate are lower, and the inhibition rate and apparent activation energy are higher when the inhibitor is added under R70 than at room temperature. Under R70, the content of oxygen-containing functional group −COOH with higher activity of inhibitor is reduced, the generation of active sites is inhibited, the concentration of active center is reduced, the path of mutual transformation between active sites and oxygen-containing functional groups is blocked, and the active groups are promoted to form a relatively stable inert oxygen-containing ether bond, which reduces the spontaneous combustion tendency of coal.