煤有机大分子碳结构石墨化机制  

Graphitization mechanism of coal organic macromolecular carbon structure

作　　者：李伍[1,2,3] 杨文斌 战星羽 李锦 LI Wu;YANG Wenbin;ZHAN Xingyu;LI Jin(Key Laboratory of Coalbed Methane Resource&Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221008,China;School of Resources and Geoscience,China University of Mining and Technology,Xuzhou 221116,China;Institute of Energy,Peking University,Beijing 100091,China)

机构地区：[1]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 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]北京大学能源研究院,北京100091

出　　处：《煤炭学报》2023年第2期855-868,共14页Journal of China Coal Society

基　　金：国家自然科学基金面上资助项目(41972169)。

摘　　要：煤化作用和石墨化作用共同控制煤的形成和演化,因煤物质成分、化学结构的复杂性和石墨化作用的特殊性,使得研究煤大分子结构热演化过程非常困难。为了探索煤化过程和石墨化过程中的大分子结构变化特征,通过煤质分析、固体核磁共振、高分辨率透射电镜(HRTEM)、黄金管热模拟等实验技术和Amsterdam Modeling Suite (AMS)量子化学计算技术,对不同煤阶煤和煤系石墨样品进行测试分析,从大分子量子化学角度构建不同煤阶煤的有机大分子结构,以揭示煤的有机质大分子碳结构演化及石墨化机制。(1)随着成熟度升高,煤大分子结构中芳香结构的占比逐渐增大,脂肪结构含量逐渐减小,芳碳率在无烟煤阶段达到0.9以上;(2)低煤级煤和中煤级煤大分子中2×2、3×3尺寸的芳香条纹含量占比最大,随着成熟度的升高优势方向(75°、90°和105°)条纹占比由26.47%增至50.10%,在无烟煤和高级无烟煤阶段出现芳香条纹堆叠现象;(3)利用构建的三维大分子结构模型开展热解模拟计算,发现随着模拟温度升高,芳香层片间距有规律的减小,从0.400 nm降至0.318 nm,这与低煤阶煤到高煤阶煤芳香层片层间距从0.467 5 nm降到0.368 0 nm的结果是一致的;(4)分析评价了煤石墨化过程中大分子结构体系的变化规律,初步认为杂原子和脂肪结构的脱除是煤芳香结构向晶簇转化的原因,并探讨了煤大分子石墨化机制,初步揭示煤化作用和石墨化作用过程中,碳结构的变化规律和演化机理。Coalification and graphitization jointly control the formation and evolution of coal.Due to the complexity of coal composition,chemical structure and the particularity of graphitization,it is very difficult to study the thermal evolution process of coal macromolecular structure.In order to carry out an exploratory research from the perspective of macromolecular quantum chemical calculation,different rank coals and coal measure graphite samples were selected in this study.The organic macromolecular structure system of different rank coals was constructed by using industrial analysis,elemental analysis,solid-state nuclear magnetic resonance,high-resolution transmission electron microscope,gold tube thermal simulation and AMS quantum chemical calculation technology,and the evolution of macromolecular carbon structure and graphitization mechanism of coal organic matter were studied.The conclusions are as follows:①With the increasing maturity,the proportion of aromatic structure in coal macromolecular structure gradually increases,the content of fat structure gradually decreases,and the aromatic carbon ratio reaches more than 0.9 in anthracite stage.②The aromatic stripe content of 2×2 and 3×3 in the macromolecules of low grade coals and medium grade coals accounts for the largest proportion,and the stripe proportion in the dominant direction(75°,90°and 105°)increases from^(2)6.47%to 50.10%with the increase of maturity.The stacking of aromatic stripes occurs in the anthracite and high anthracite stages.③The three-dimensional macromolecular structure model was used to carry out pyrolysis simulation calculation.It was found that with the increase of simulation temperature,the aromatic lamellar spacing decreases regularly from 0.400 nm to 0.318 nm,which is consistent with the result that the aromatic lamellar spacing from low rank coal to high rank coal decreases from 0.4675 nm to 0.3680 nm.④The change law of macromolecular structure system in the process of coal graphitization was analyzed and evaluated.It w

关 键 词：煤 大分子结构 煤化作用 石墨化 热解 

分 类 号：TQ530[化学工程—煤化学工程]