太原西山七里沟石炭系煤系页岩组成结构及热解特征分析

Carboniferous Coal Measures Shale Composition,Structural and Pyrolysis Features Analysis in Qiligou,Xishan Coalfield,Taiyuan

以太原西山煤田七里沟石炭系煤系页岩为研究对象,采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和热重质谱(TG-MS)研究其矿物组成、结构特征及热解行为。结果表明:①东大窑段底部页岩中黏土矿物含量最高,对热解生烃的促进作用最大;②畔沟段、晋祠段和毛儿沟段页岩为Ⅲ型干酪根,东大窑段页岩均为Ⅱ型干酪根。畔沟段页岩中芳香类化合物含量最多,东大窑段底部页岩的生烃潜力‘A’最大,脂肪结构最为富集;③400℃之前,毛儿沟段页岩的热失重量最大,C_(2)H_(6)生成强度最大,受沉积环境影响,产生大量含硫气体;400~650℃,东大窑段底部页岩的热失重量最大,CH_(4)等烃类气体生成强度最大;650~950℃,畔沟段页岩的热失重量较大,生成大量H_(2)和C_(6)H_(6);④样品的热解参数与其结构参数有关,随着脂肪结构占比和生烃潜力“A”的增大,400~650℃的热失重量增大;随着芳香结构占比和芳香缩聚程度指数DOC_(1)的增大,650~950℃的热失重量分段性增大;随着有机质成熟度‘C’的增大,最大热失重速率峰温分段性减小。

Taking the Carboniferous coal measures shale in the Qiligou,Xishan coalfield,Taiyuan as the subject investigated has used X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and thermogravimetry-mass spectrum analysis(TG-MS)to study its mineral composition,structural features and pyrolysis behavior.The results have shown:①clay mineral content is largest in the Dongdayao member bottom shale,and promotion to pyrolytic hydrocarbon generation is maximum;②shale kerogen in Pangou,Jinci and Maoergou members belongs to type III,Dongdayao member type II,aromatics content in Pangou member shale is the most,Dongdayao member bottom shale has largest hydrocarbon generation potential“A”,fat structure is most enriched;③before 400℃,shale in Maoergou member has maximum heat loss,C_(2)H_(6)generation intensity maximum,impacted by sedimentary environment,generated a great deal sulfur-bearing gases;during 650~950℃,shale in Pangou member has rather large heat loss,and generated a great deal H_(2)and C_(6)H_(6);④pyrolysis parameters of sample are related to its structural parameters,with the increasing of fat structure proportion and hydrocarbon generation potential“A”,heat loss during 400~650℃increasing;with increasing of aromatic structure proportion and aromatic polycondensation degree index DOC_(1),heat loss stepwise increasing during 650~950℃;with increasing of organic matter maturity“C”,maximum heat loss rate peak temperature stepwise decreasing.