Inhibitive Effects of Antioxidants on Coal Spontaneous Combustion

Abstract

Based on the deep study of the mechanism of coal spontaneous combustion, this paper proposes new efficient inhibitors preventing coal spontaneous combustion from the perspective of inhibition of free-radical chain reactions. Chifeng coal samples were used as the research object, and six different types of antioxidants were selected as the inhibitor for low-temperature oxidation experiments. A comparison study of the gas product concentration before and after inhibition was conducted; its inhibition mechanism was also studied and analyzed. On the basis of this, the specific indicators, such as cross-point temperature (CPT), apparent activation energy, active functional groups, and an inhibitory rate at 100 °C were used to compare the inhibition effect of antioxidants. The experiments indicate that, except for oxygen-scavenger ascorbic acid, another five antioxidants (butylated hydroxytoluene, BHT; triphenyl phosphite, TPPI; 2,2,6,6-tetramethyl-1-piperidine-noxyl free radical, TEMPO; edetic acid, EDTA; and phytic acid, PA) exhibit a good inhibition effect, and the order of inhibitory effect is RTEMPO> RBHT> REDTA> RTPPI> RPA, indicating that TEMPO has the best inhibition effect with the activation energy of coal oxidation increased by 14.79 kJ·mol–1, and the inhibition rate reached 73.08%. The research results provide new ideas for the prevention and control of coal spontaneous combustion.