陕西省子长矿区晚三叠世5号煤层的煤岩煤质特征

The features of petrology and quality of coal in Late Triassic No.5 coal in Zichang mining area in Shaanxi Province

对采自陕西省子长县枣林永胜煤矿的晚三叠世5号煤层剖面进行了详细的煤岩学研究，报道了我国北方三叠纪陆相环境形成的煤层的煤岩、煤质特征。研究成果显示，永胜煤矿的晚三叠世5号煤层具有特低硫含量（St．d为0．10％～0．399／6）、低或中灰分含量（Ad为7．22％～29．45％）、高挥发份产率（Vdaf为31．899／6～45．36％）及变质程度低（Ro,ran为0．83％～0．89％）等特征；镜质组含量较高（41．8％～93．9％，无矿物基），惰质组含量次之（2．6％～52．5％），壳质组含量较低（3．5％～8．5％）。宏观煤岩类型和显微组分的垂向变化显示在煤层底部和煤层顶部的分层光泽较亮、镜质组含量高；而在煤层中部的分层光泽较暗、惰质组含量高，反映了聚煤早期和晚期阶段泥炭沼泽环境比较潮湿，而中期阶段变得干燥的演变特征。

This paper studies in detail the coal petrology in section samples from the late Tri- assic No. 5 coal seam in Zaolin Yongsheng Mine in Zichang County, and reports the petrological, mineralogical features of the coal seam formed in late Triassic continental environment in North- ern China. The results show that the No. 5 coal seam has a low sulfur content （St.d, 0. 10% to 0. 39%）, a low-middle ash content （Ad, 7. 22% to 29.45%）, a high volatile yield （Vdaf, 31.89% to 45.36%）, and a low metamorphic grade （R 0.83% to 0.89%）; the proportion of total vitrinite （41.8% to 93.9%; mineral-free basis ） is higher than that of total inertinite （2.6% to 52.5%） and that of total exinite （3.5% to 8.5%）. Macroscopic type and vertical variation in the microscopic components of the coal seam show that the vitrinite contents are more in the bottom and top portion of the coal seam and the inertinite is abundant in the middle part, which indicates that the peat swamp environment was damper in the early and late stages of the coal accumulating period and drier in the intermediate stage.