Study on the Inhibition of Coal Spontaneous Combustion by Superabsorbent Antioxidant Inhibitors

Aiming at the problems of short inhibition life and low efficiency of physical inhibitors for the prevention and control of coal spontaneous combustion, this paper utilizes super water-absorbent (SAR) resin with tea polyphenol (TP) and vitamin C (VC) to prepare an inhibitor that can continuously and efficiently inhibit coal spontaneous combustion. Through the procedure of heating, thermogravimetric experiments are performed to characterize the inhibition performance of super-water-absorbent antioxidant-type inhibitor, and the change of active functional groups in the original coal and inhibited coal samples. The experimental results show that the super-water-absorbent antioxidant retardant can inhibit the coal spontaneous combustion in the low-temperature oxidation stage by absorbing heat through water evaporation and lowering the temperature to isolate the oxygen, and in the super-temperature stage by reducing the number of active functional groups in the coal. Compared with that of the original coal, and the water retention of the highly absorbent resin played the role of cooling and oxygen barrier for the coal; the apparent activation energy of the resisted coal samples in the spontaneous combustion in the three stages of oxygen uptake and weight gain, pyrolysis, and combustion increased by 41.02 kJ/mol, 92.58 kJ/mol, and 133.7 kJ/mol. In the process of temperature increase, the content of -OH, -CH2, -COOH, C=C, and C-H functional groups in the resisted coal samples was lower than that of the original coal, and -OH and -CH2 in the resisted coal samples showed a tendency to decrease, which reduced the reactive functional groups. Therefore, the superabsorbent antioxidant inhibitors can inhibit coal spontaneous combustion reactions by reducing the activity of coal molecules and delaying the process of coal spontaneous combustion reactions through releasing water, absorbing heat, and covering oxygen. The results of this study can be used as a reference for the field of inhibition of coal spontaneous combustion by chemical inhibitors.