Study on the mechanism of lignite oxidation inhibition by antioxidant resveratrol

A comparative study on the mechanism of inhibiting spontaneous combustion of lignite by the antioxidant resveratrol (RES) with different ratios has been performed. The microstructure, thermodynamic characteristics, and inhibiting reaction process was explored. RES has the best inhibition effect at wt 1%, the order of reduction of functional groups is aliphatic hydrocarbon > aromatic hydrocarbon > hydroxyl group > oxygen-containing functional group. Combined with the change characteristics of microstructure and thermal release, RES can effectively inhibit the oxidation of lignite. The results of quantum chemical calculation clearly indicate that the best active site for the reaction of the three positions of hydroxyl (①, ② and ③) in RES with the coal molecular structure is the ③. The order of the reaction for RES with the four types of radicals is –CH2-O-O·>-CH2-O·>·OH > -CH2·. Combined with the above analysis, the inhibition mechanism is inferred that this reaction reduces the collision frequency of free radicals, interrupts or slows down the intermediate process of coal free radical reaction, so that the thermal release is affected, and finally achieves the inhibiting CSC. This work solves the problem of high inhibition cost, complex sequence of active reactions, and unclear reaction mechanism.