陕北三叠纪煤显微组分特征对热解焦油组成影响研究

Study on the influence of microscopic composition characteristics of Triassic coal in northern Shaanxi on the composition of pyrolysis tar

通过密度梯度法富集了陕北三叠纪高油煤中镜质组(ZCV)单组分与惰质组(ZCI)单组分,发现不同单组分分子结构差异显著,组分组成与热解焦油组成之间存在显著耦合关系,ZCV脂肪碳相对含量为34.42%,其中脂甲基碳与氧取代芳香碳相对含量较高、脂肪侧链较长、芳香环上的脂肪长链结构和烷基侧链结构丰富、无定型碳相对含量较高;ZCI芳碳率高达77.29%、羰基和羧基相对含量较高、芳香度较高;ZCV热解焦油产率、热解气、热解水产率较高,半焦产率最低,焦油中脂肪烃类化合物以链烷烃为主、酚类化合物含量较高,这与ZCV分子结构中脂肪侧链较长、脂肪碳与氧取代芳碳含量较高密切相关;ZCI热解产物产率与ZCV相反,焦油中不饱和烃类化合物、多环芳烃(三环、四环)含量相对较多,这与ZCI分子结构中芳香碳含量较高、芳环缩合度较大不无关系。

The density gradient method was used to concentrate vitrinite(ZCV)and inertinite(ZCI)components in the Triassic high tar coal in northern Shaanxi,it was found that the substructure of different components was significantly different,and there was a significant coupling relationship between the component composition and the pyrolysis tar composition.The relative content of fatty carbon in ZCV was 34.42%.Among them,the relative content of methyl carbon and oxygen-substituted aromatic carbon is higher,the fatty side chain is longer,the fatty long chain structure and alkyl side chain structure in aromatic ring are abundant,and the relative content of amorphous carbon is higher.The aromatic carbon content of ZCI is as high as 77.29%,the relative content of carbonyl group and carboxyl group is higher,and the aromatic degree is higher.The yield of tar,pyrolysis gas,and pyrolysis water in ZCV pyrolysis is relatively high,while the yield of semi coke is the lowest.The aliphatic hydrocarbons in tar are mainly alkanes and the phenolic compounds are higher,which is closely related to the longer aliphatic side chain and the higher content of aliphatic carbon and oxygen-substituted aryl carbon in ZCV molecular structure.The yield of ZCI pyrolysis products is opposite to that of ZCV,and the relative content of unsaturated hydrocarbons and polycyclic aromatic hydrocarbons(tricyclic and tetracyclic)in tar is relatively high,which is not unrelated to the high content of aromatic carbon and the high degree of aromatic ring condensation in ZCI molecular structure.