Study on the inhibition of coal oxidation characteristics and thermal effect of Luteolin/Tea polyphenols/Urea

•LTU had an obvious synergistic effect on the inhibition of coal spontaneous combustion.•The physical components of LTU could encapsulate coal, insulate oxygen, absorb heat and decrease the temperature.•The chemical components of LTU could consume (-OH), (RO-), (ROO-) and inert the free radicals in the chain reaction. In this study, to address the problems of the weak inhibition effect and short action time of a single inhibitor on coal oxidation, a novel composite inhibitor of Luteolin/Tea polyphenol/Urea (LTU) was proposed. The inhibition effects and mechanisms of LTU and other traditional inhibitors (NaHCO3 and VC) on coal sample oxidation were compared and analyzed using a C600 high-precision calorimeter, a temperature-programmed oxidation device and Fourier transform infrared spectroscopy. The experimental results showed that LTU had an obvious synergistic effect on the inhibition of coal spontaneous combustion (CSC): 1) LTU could increase the initial exothermic temperature point, prolong the endothermic stage, and reduce the exothermic intensity of coal-oxygen reaction; 2) The coal sample treated with LTU showed a significant decrease in the concentration of carbon oxygen and alkane gases released, and an increase in the gas production temperature point, which was better than the inhibition effect of NaHCO3 and VC under the same conditions. 3) The physical components of LTU could encapsulate the coal, insulate the oxygen, absorb heat and decrease the temperature; moreover, its chemical components could consume (–OH), (RO-), (ROO-) in the chain reaction, inert the free radicals in the chain reaction, inhibit oxidization and block CSC. This study provides an efficient and economical chemical inhibitor for safe production in the coal industry and important theoretical support for a deeper understanding of the CSC inhibition mechanism.