中低煤阶镜煤/暗煤大分子结构及对甲烷吸附的影响  

Macromolecular structure of vitrain/durain in medium-low rank coal and its effect on methane adsorption

作　　者：惠鹏 马东民[1] 陈跃[1] 王丽雅 李卫波 滕金祥 李国富 杨甫 郑超 HUI Peng;MA Dongmin;CHEN Yue;WANG Liya;LI Weibo;TENG Jinxiang;LI Guofu;YANG Fu;ZHENG Chao(College of Geology and Environment,Xi’an University of Science and Technology,710054 Xi’an,China;Shaanxi Hancheng Tianjiu Grouting Exploration Company Limited,715499 Hancheng,China;Shaanxi Geological Science and Technology Center,710054 Xi’an,China;Key Laboratory of Coal and Coalbed Methane Co-mining Technology,048000 Jincheng,China;Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources,710021 Xi’an,China)

机构地区：[1]西安科技大学地质与环境学院,西安710054 [2]陕西韩城天久注浆勘探有限责任公司,陕西韩城715499 [3]陕西省地质科技中心,西安710054 [4]煤与煤层气共采技术国家重点实验室,山西晋城048000 [5]自然资源部煤炭资源勘查与综合利用重点实验室,西安710021

出　　处：《煤炭转化》2023年第3期25-38,共14页Coal Conversion

基　　金：国家自然科学基金项目(41902175);山西省科技计划揭榜招标项目(20201101002);陕西省地勘基金公益性项目。

摘　　要：为研究中低阶煤不同宏观煤岩组分微观结构及对甲烷吸附的影响,采集黄陇煤田郭家河、大佛寺、园子沟及黄陵矿区的四种不同煤样,手工剥离不同宏观煤岩成分(镜煤和暗煤),通过傅立叶红外光谱(FTIR)分析、X射线衍射(XRD)分析和等温吸附实验探究中低阶煤分子结构特征及其对甲烷吸附能力的影响。结果表明:同一煤样中镜煤的水分和挥发分产率高于暗煤的水分和挥发分产率,而暗煤的灰分产率和固定碳含量高于镜煤的灰分产率和固定碳含量。镜煤的显微组分中镜质组含量较大、惰质组含量较低,暗煤则相反。红外光谱分析结果表明,同一煤层的镜煤和暗煤红外光谱吸收峰形态相似,官能团类型和含量接近。煤分子结构中主要含氧官能团按含量由高到低依次为C—O,COOH,C=O,脂肪侧链按含量由高到低依次为CH_(2),CH_(3),CH。对比煤的准晶体结构发现,中低阶煤煤化程度低,γ带的峰面积整体较大。受煤化作用和压实作用影响,暗煤的堆砌度和堆砌层数大于镜煤的堆砌度和堆砌层数。分子结构特征对甲烷吸附量的影响显著。镜煤的最大甲烷吸附量与芳碳率和缩合度均呈正相关,暗煤的最大甲烷吸附量与芳碳率和缩合度均呈负相关。镜煤和暗煤的最大甲烷吸附量随羟基相对含量增加而减小,碳氧双键(羰基和羧基)相对含量对甲烷吸附量的影响有限。In order to investigate the microstructure of different lithotype components of medium-low rank coals and their effects on methane adsorption,four kinds of coal samples were collected from Guojiahe,Dafosi,Yuanzigou and Huangling in Huanglong coal mines,and different macro-coal petrographic components(vitrain and durain)were manually stripped.The molecular structure characteristics of medium-low rank coals and their effects on methane adsorption capacity were investigated by Fourier infrared spectroscopy(FTIR),X-ray diffraction(XRD)and isothermal adsorption experiments.The results show that the moisture and volatile yields of vitrain are higher than those of durain,while the ash yield and fixed carbon content of durain are greater than those of vitrain in the same coal sample.The content of vitrinite in the vitrain is higher and the content of inertinite is lower.The experimental results of FTIR show that the absorption peaks of vitrain and durain in the same coal seam are similar in shape,and the types and contents of functional groups are approximate.The main oxygen-containing functional groups in the molecular structure of coal are C—O,COOH and C=O from the highest content to the lowest content,and the fatty side chains are CH_(2),CH_(3) and CH in content descending order.Comparing the quasicrystal structure of coal,it is found that the coalification degree of medium-low rank coals is low and the peak area of γ-band is larger overall.The stacking height and number of stacking layers of durain are higher than those of vitrain due to the influence of coalification and compaction.The molecular structure has a significant effect on the methane adsorption capacity.The maximum methane adsorption capacity of vitrain is positively correlated with both aromatic carbon rate and condensation degree,while the maximum methane adsorption capacity of durain is negatively correlated with aromatic carbon rate and condensation degree.The maximum methane adsorption capacity of vitrain and durain decreases with the increase of

关 键 词：黄陇煤田 镜煤/暗煤 分子结构 准晶体结构 吸附能力 

分 类 号：TQ530[化学工程—煤化学工程]