富油煤是集煤、油、气属性于一体的特殊煤基油气资源，其安全高效开发和利用对保障我国油气自给能力、减缓油气对外依存度具有重要意义。富油煤的煤质结构导致其开采过程中容易发生自燃灾害。为明确富油煤自燃机理，本文选取陕西省典型矿区的4种富油煤和2种含油煤为研究对象，围绕富油煤氧化动力学特征及关键活性基团变化规律展开研究，主要结论如下：

富油煤的水分、挥发分和C元素含量较高，分别在4~8%、34~40%和75~78%之间，矿物含量较低，灰分含量与焦油产率呈负相关，随着焦油产率增大，煤的芳香化程度降低，富油煤微晶结构单元体积较小，煤大分子结构单元的芳构化和缩合程度较弱，桥键、侧链和含氧官能团等不稳定结构增多，氧化性增强。

富油煤初始放热温度低于含油煤，放热量随焦油产率的升高而增大，富油煤放热量为16267.19~18552.87J/g。随着焦油产率升高，煤氧化失重量增大，受热分解和燃烧阶段的持续时长减少，煤样的临界、干裂和燃尽温度点降低，增速、受热分解、着火和最大失重速率温度的变化呈先降低后升高趋势。表观活化能在吸氧增重和受热分解阶段随温度上升而增加，在燃烧阶段逐渐降低，富油煤在燃烧阶段的平均活化能低于含油煤。

富油煤氧化特性与活性基团之间存在显著的相关关系，其中热效应为主要表征因素。在吸氧增重阶段，含油煤中醚键和C=O的消耗对氧化放热起关键的促进作用，随着焦油产率升高，富油煤中C=O和芳烃-CH键的含量变化促进了氧化放热。在受热分解阶段，富油煤的脂肪族-CH弯曲振动结构和芳烃-CH键的生成对氧化放热具有关键的促进作用。在燃烧阶段，脂肪族-CH伸缩振动结构、羟基、C=O等结构是富油煤的关键活性基团，芳烃-CH结构的生成对热效应有抑制作用，其它基团的消耗均促进了氧化放热。

Tar-rich coal is a special coal-based tar and gas resource that combines the properties of coal, tar and gas, and its safe and efficient development and utilisation is of great significance to safeguard China's tar and gas self-sufficiency and slow down its tar and gas dependence on foreign countries. The coal structure of tar-rich coal leads to spontaneous combustion disaster during the mining process. In order to clarify the mechanism of spontaneous combustion of tar-rich coal, this paper selects four kinds of tar-rich coal and two kinds of tar-containing coal in typical mining areas of Shaanxi Province as the research object, and focuses on the characteristics of oxidation dynamics of tar-rich coal and the change rule of the key reactive groups to carry out the research, and the main conclusions are as follows:

The moisture, volatile matter and C element contents of tar-rich coal are higher, between 4~8%, 34~40% and 75~78% respectively, and the mineral content is lower, the ash content is negatively correlated with the tar yield, and the degree of coal aromatisation decreases with the increase of tar yield, the volume of the microcrystalline structural unit of the tarl-rich coal is smaller, the degree of aromatisation and condensation of the coal macromolecular structural unit is weaker, and unstable structures, such as the bridge bond, the side chain, and the oxygen-containing functional group, increase. The unstable structures such as bridge bonds, side chains and oxygen-containing functional groups increase, and the oxidative property increases.

With the increase of tar yield, the weight loss of coal oxidation increased, the duration of thermal decomposition and combustion stage decreased, the critical, dry cracking and combustion temperature points of coal samples decreased, and the changes of the temperature of growth rate, thermal decomposition, ignition and maximum weight loss rate showed a tendency of decreasing and then increasing. The initial exothermic temperature of tar-rich coal was lower than that of tar-containing coal, and the exothermic amount increased with the increase of tar yield, and the exothermic amount of tar-rich coal ranged from 16,267.19 to 18,552.87 J/g. The apparent activation energy increased with the increase of temperature in the stage of oxygen uptake, weight gain, and thermal decomposition, and decreased gradually in the stage of combustion, and the average activation energy of tar-rich coal was lower than that of tar-containing coal in the stage of combustion.

The higher the tar yield, the higher the correlation between the internal transformations of the groups in the coal structure. There is a significant correlation between the oxidation characteristics of tar-rich coals and the reactive groups, in which the thermal effect is the main characterisation factor. In the oxygen uptake and weight gain stage, the consumption of ether bonds and C=O in the tar-rich coal played a key role in promoting the oxidative exotherm, which was facilitated by the change in the content of C=O and aromatic-CH bonds in the tar-rich coal with the increase in tar yield. In the thermal decomposition stage, the aliphatic-CH bending vibrational structure and the generation of aromatic-CH bonds in the tar-rich coal play a key role in promoting the oxidative exotherm. In the combustion stage, the aliphatic-CH stretching vibrational structure, hydroxyl group, C=O and other structures are the key reactive groups of the tar-rich coal, the generation of aromatic-CH structure has an inhibitory effect on the thermal effect, and the depletion of all the other groups promotes the oxidative exotherm.

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