Influence of inert gas atmosphere on the oxidation reaction of active groups in coal:Experimental and simulation studies

GAO Fei; BAI Qihui; ZHOU Xihua; BAI Gang; ZHANG Xun

doi:10.13225/j.cnki.jccs.2024.1032

Abstract：To study the influence and inerting mechanism of inert gas atmosphere on the oxidation of active groups in coal,Shuiyu(SY)bituminous coal and model compounds were taken as the objects of the research.A combination of tem-perature-programmed and Fourier transform infrared spectroscopy(FT-IR)experiments and quantum chemical calcula-tions was used to compare the differences in the inhibition effects of CO2 and N2 on different active groups from both ex-perimental and simulation perspectives and to reveal the inerting mechanisms of CO2 and N2 on the reaction of active groups with O2 in coal.The results showed that CO2 was more effective than N2 in inerting the oxidation reaction of act-ive functional groups in coal and reducing the generation of oxygen-containing functional groups in coal.The higher the temperature,the more consistent the inerting effect of two atmospheres on the oxidation reaction of active groups.The dif-ference between the two atmospheres on the inerting effect on the oxidative process of oxygen-containing functional groups in coal was large,and the difference on the inerting effect on the oxidative process of aliphatic hydrocarbons in coal was smaller.The reactivity of the active H atoms in the groups was decreased by both CO2 and N2,which changed the positions of the nucleophilic reactive sites for individual active groups,and CO2 was more significant than N2 in decreas-ing the reactivity of the active H atoms.Among them,the influence of N2 on the chemical adsorption of alkanes with O2 was greater,while CO2 on the chemical adsorption of oxygen-containing functional groups with O2 was greater.Whether the two atmospheres inhibit or promote the oxidation reaction of the active group,the possibility and heat release of the oxidation reaction for the system after the interaction of CO2 with the active group was lower than that of N2.The effect of inert gas type on the chemical adsorption and oxidation reaction of oxygen-containing functional groups with O2 was more significant,and the effect on aliphatic hydrocarbons was smaller.Therefore,the difference of inerting effect between CO2 and N2 on coal spontaneous combustion was closely related to the type of functional groups in coal and temperature.In the technology for fire prevention of inert gases in underground coal mines,the type of inert gas should be comprehensively evaluated according to the type and composition of functional groups in coal and the field temperature.