摘要
为定性和定量研究煤的分子孔隙分布情况,选取屯留矿区煤样为研究对象,通过元素分析、固体^(13)C核磁共振和X射线光电子能谱等实验测试并分析了屯留矿煤样的化学结构,构建了煤分子模型。利用分子模拟技术,重构了煤样的分子孔隙。采用最大球算法原理,对分子孔隙模型进行孔隙识别,基于提取的孔隙网络模型对孔隙结构参数进行简化计算,实现了对煤分子孔隙结构的三维可视化表征和定量分析。利用CO_(2)吸附法测试了煤样的孔径分布、比表面积和孔容等孔隙结构参数,与模型对应的孔隙分布特征进行了对比。结果表明,屯留煤样孔径小于1 nm的分子孔隙孔径分布曲线呈现双峰特征,第1峰范围内孔隙的孔径小于0.7 nm,属于极微孔,第2峰范围内孔隙的孔径大于0.7 nm,属于超微孔;孔径在0.40~0.65和0.70~0.89 nm的孔隙数量较多,比表面积和孔容较大;孔隙平均配位数为2.32,大多数孔隙由2个及以上的喉道连通,说明孔隙连通性较好;孔喉半径比主要在1.00~2.00,极少在4.50~7.50,说明煤样孔径小于1 nm的分子孔隙空间发育比较均匀,但在孔隙空间的局部区域存在较大尺寸变化;模型的孔隙分布特征与CO_(2)吸附法测试结果相比,孔径分布曲线趋势相似,数值相近,说明利用煤分子重构煤的分子孔隙并进行孔隙结构的表征与分析是可行的。
To study the molecular-scale pore structure of coal,the coal sample in the Tunliu mine was taken as the research object.The chemical structure of the coal sample from Tunliu mine was tested and analyzed by ultimate analysis,solid ^(13)C NMR and X-ray photoelectron spectroscopy,and a molecular model of coal was constructed.Then the molecular pores of the coal sample were reconstructed using molecular simulation techniques.The maximal ball method was used for the pore identification of molecular pore model,and the simplified calculation of pore structure parameters based on the extracted pore network model,which realized the three-dimensional visual characterization and quantitative analysis of coal molecular pore structure.The pore structure parameters such as the pore size distribution,specific surface area and pore volume of the coal sample were tested by the CO_(2) adsorption method and compared with the pore distribution characteristics corresponding to the model.The results are as follows:the pore size distribution curve of molecular pores with pore size less than 1 nm in the Tunliu coal sample shows a bimodal feature.The pore size of pores in the first peak range is less than 0.7 nm,which belongs to narrow micropore,and the pore size of pores in the second peak range is greater than 0.7 nm,which belongs to ultra-micropore.The number of pores with pore sizes in the range of 0.40-0.65 nm and 0.70-0.89 nm is higher,and they have larger specific surface area and pore volume.The average coordination number of pores is 2.32,and most of the pores are connected by two or more throats,indicating a good pore connectivity.The pore-throat radius ratios are mainly in the range of 1.00-2.00 and rarely in the range of 4.50-7.50,indicating that the molecular-scale pore space of the coal sample is uniformly developed,but large size variations existed in local areas of the pore space.Compared with the results measured by the CO_(2) adsorption method,the pore size distribution curve trend and numerical value of the model are s
作者
孟筠青
张硕
曹子豪
王琛
MENG Junqing;ZHANG Shuo;CAO Zihao;WANG Chen(School of Emergency Management and Safety Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;State Key Labo⁃ratory of Coal Resources and Safe Mining,China University of Mining and Technology-Beijing,Beijing 100083,China;Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2022年第S01期160-170,共11页
Journal of China Coal Society
基金
国家自然科学基金联合基金重点资助项目(U1704242)
中央高校基本科研业务费专项资金资助项目(2021YQAQ02)
关键词
煤分子
分子孔隙
最大球算法
孔径分布
孔喉半径比
coal molecule
molecular-scale pore
maximal ball method
pore size distribution
pore-throat radius ratio
