Experimental study on the inhibition effect of inhibitors on coal spontaneous combustion during long-term low-temperature oxidation process

To elucidate the long-term inhibitory effects of inhibitors on coal spontaneous combustion in mines and their underlying mechanisms, programmed heating, thermogravimetric analysis, and Fourier-transform infrared spectroscopy were employed to investigate the effects of magnesium chloride, resveratrol, and tea polyphenols during prolonged low-temperature oxidation. The results show that the inhibitory effects of all three inhibitors initially increase and then decline with oxidation time. Based on CO and CO 2 evolution, CO inhibition rates, and apparent activation energy, the inhibitory performance reaches an optimum at approximately 1000 h. At this stage, tea polyphenols exhibit the strongest inhibitory effect, achieving a maximum CO inhibition rate of 39.71% and increasing the apparent activation energy by 31%. Microstructural analysis indicates that all three inhibitors effectively suppress the formation or consumption of four key reactive functional groups (–CH 2 , –CH 3 , C=O, and –COOH) during long-term oxidation. Compared with MgCl 2 , the two natural antioxidants—resveratrol and tea polyphenols—exhibit stronger inhibitory effects, particularly on aliphatic side chains (–CH 2 and –CH 3 ), with tea polyphenols achieving a maximum inhibition rate of 58.34% for –CH 2 groups. In addition, resveratrol shows more pronounced inhibition toward carbonyl (C=O) groups, whereas tea polyphenols exhibit greater selectivity toward carboxyl (–COOH) groups, with maximum inhibition rates of 35.12% and 46.61%, respectively. Overall, MgCl 2 demonstrates comparatively weaker inhibitory performance. These results confirm that inhibitors suppress coal spontaneous combustion primarily by disrupting chain-reaction pathways and reducing the concentration of reactive functional groups.