煤缩合芳环应力响应:对无烟煤石墨化的启示  

Stress response of coalcondensed aromatic ring: Inspiration for graphitization of anthracite

作　　者：宋昱[1,2] 姜波[1,2] 王猛[1,2,3] 李凤丽[1,2] 程国玺[1,2] 侯晨亮[1,2] 冯光俊 全方凯 SONG Yu;JIANG Bo;WANG Meng;LI Fengli;CHENG Guoxi;HOU Chenliang;FENG Guangjun;QUAN Fangkai(School of Resources and Geoscience,China University of Mining&Technology,Xuzhou 221116,China;Key Laboratory of Coal bed Methane Resource&Reservoir Formation Process Ministry of Education,China University of Mining&Technology,Xuzhou 221008,China;Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization,China University of Mining&Technology,Xuzhou 221008,China)

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008 [3]中国矿业大学江苏省煤基温室气体减排与资源化利用重点实验室,江苏徐州221008

出　　处：《煤炭学报》2022年第12期4336-4351,共16页Journal of China Coal Society

基　　金：江苏省自然科学基金资助项目(BK20200663);国家自然科学基金资助项目(42102210,41430317)。

摘　　要：浅层次(<5 km)滑脱构造中剑鞘褶皱的发现预示着脆性变形域中同样发育有煤层韧性剪切带,且其结构-构造特征和伴生石墨矿化现象已被人们所认识,然而对于煤大分子缩合芳环应力响应特征则知之甚少,且缺乏实验论证及理论分析。以原生结构无烟煤的高温高压变形实验,高分辨率透射电子显微镜(HRTEM)以及X射线衍射(XRD)分析为主要研究方法,分析次高温条件下(<300℃)应力(~200 MPa)和应变速率(1×10^(-5)~1×10^(-7)s^(-1))对煤中缩合芳环结构有序性的影响,揭示不同应力状态和应变速率条件下煤缩合芳环的结构有序化演化规律及其对无烟煤石墨化成矿的启示。结果表明,高构造应力和低应变速率使得无烟煤大分子缩合芳环长度生长,定向性增强;2者对缩合芳环结构有序性的影响最为显著。煤中缩合芳环弯曲程度随着差异应力和静水压力的升高而升高,随着应变速率的降低而升高;堆叠程度则随着差异应力的升高和应变速率的降低而略微升高,对静水压力和温度的变化不敏感。XRD结果显示缩合芳环碳网间距随着构造应力的升高和应变速率的降低而逐渐降低,与HRETM的表征结果一致。实验结果表明除温度之外,高差异应力和低应变速率是无烟煤大分子基本结构单元有序化增强的关键因素。作为上地壳力学性质最为软弱的岩层,煤大分子缩合芳环应力响应特征研究对于无烟煤石墨化成矿作用有重要启示作用。The discovery of scabbard fold in shallow(< 5 km)detachment structure indicates that the coal seam ductile shear zone could also be developed in the brittle deformation domain, whose structural characteristics and associated graphite mineralization have been recognized internationally. However, the research on the evolution mechanism of ultra-fine structure order in the process of coal ductile rheology is still not sufficient, and there is a lack of experimental demonstration and theoretical analysis. In this study, the high-temperature and high-pressure deformation experiment on primary structure anthracite, high-resolution transmission electron microscope(HRTEM),and X-ray diffraction(XRD)are used as the main research methods to simulate the effects of stress and strain rate on the structural alignment of the condensed aromatic ring(CAR). It is supposed to reveal the structural order evolution of coal CAR under different stress states and strain rates and its enlightenment on the graphitization of anthracite. The results indicate that the high tectonic stress and low strain rate enhance the length and directionality of anthracite macromolecular CAR. Both have the most significant effect on the order of CARs. The curvature of coal CARs increases with the enhancement of differential stresses and hydrostatic pressure, however, it decreases with the decreasing strain rate. The stacking extent slightly increases with the enhancement of differential stresses and decreasing strain rate, where the stacking extent is insensitive to the hydrostatic pressures. The XRD results show that the spacing of CAR networks decreases with the increase of tectonic stress and the decrease of strain rate, which is consistent with the HRETM results. The experimental results show that besides temperature, high differential stress, and low strain rate are the key factors for the enhancement of CAR structural alignment for anthracite. The study on the stress response characteristics of CAR within coal macromolecules has an important implica

关 键 词：无烟煤石墨化 煤缩合芳环 碳网间距 构造应力 应变速率 多层次滑脱 

分 类 号：TQ53[化学工程—煤化学工程]