Research on the influence of different antioxidants on the thermal behavior of coal spontaneous combustion

Abstract

To explore the effects of different antioxidants on thermal behavior characteristics of coal spontaneous combustion (CSC), four antioxidants including tea polyphenols, ethylenediaminetetraacetic acid, melatonin, and β-beta-carotene were studied in this paper. The thermal effects and changes in thermal property parameters of coal treated with different antioxidants were obtained by differential scanning calorimetry experiments and thermal property parameter testing experiments. The results reveal that the effect of antioxidants on heat released by coal oxidation is mainly reflected in slow heat release stage. Among them, tea polyphenols have the most significant effect on inhibiting CSC, manifested by an increase of 14.8 °C in initial heat release temperature, a maximum increase of 109.8 kJ/mol in activation energy during this stage, and an effective reduction of 791.5 J/g in heat release. Compared with original coal sample, thermal diffusivity and conductivity of antioxidant-treated coal sample are lower, and specific heat capacity is higher. Furthermore, the thermal effect of antioxidant inhibition of key free radical (• OH) reactions was determined using quantum chemistry methods. Results indicate that during the process of reducing • OH, the main reaction occurring is hydrogen abstraction reaction of • OH on active sites of antioxidants. This is an exothermic reaction and must carry out at a certain temperature. Provide theoretical basis for the development of efficient resistive materials.