基于压汞、低温N_2吸附和CO_2吸附的构造煤孔隙结构表征  

Characterization on pore structure of tectonic coals based on the method of mercury intrusion,carbon dioxide adsorption and nitrogen adsorption

作　　者：李阳[1,2,3] 张玉贵 张浪[2,3] 侯金玲[2,3] LI Yang;ZHANG Yugui;ZHANG Lang;HOU Jinling(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Mine Safety Technology Branch,China Coal Research Institute,Beijing 100013,China;State Key Laboratory of Coal Mining and Clean Utilization (China Coal Research Institute),Beijing 100013,China)

机构地区：[1]河南理工大学安全科学与工程学院,河南焦作454000 [2]煤炭科学技术研究院有限公司安全分院,北京100013 [3]煤炭资源高效开采与洁净利用国家重点实验室(煤炭科学研究总院),北京100013

出　　处：《煤炭学报》2019年第4期1188-1196,共9页Journal of China Coal Society

基　　金：国家科技重大专项资助项目(2016ZX05045-007-007);国家自然科学基金资助项目(51704164);河南省高校科技创新团队支持计划资助项目(14IRSTHN002)

摘　　要：我国煤层受多期次构造运动影响构造煤普遍发育,构造煤孔隙大小分布尺度较广(毫米～纳米级),孔隙结构较为复杂。不同尺度的孔隙结构控制着煤层气的吸附-解吸(孔隙表面)、扩散(纳米级孔隙)与渗流(微米～毫米级孔隙)等过程,是影响煤层气储存与运移的重要因素。为研究构造煤不同尺度孔隙结构的分布特征与演化规律,在潞安矿区采集4种破坏类型煤样,利用压汞法、低温N_2吸附法及CO_2吸附法分别测试了煤样的孔隙分布特征,对比分析了各测试方法的优势孔径段,提出利用CO_2吸附法表征构造煤微孔(<2 nm)、低温N_2吸附法表征介孔(2～50 nm)、压汞法表征大孔结构(>50 nm)的孔隙结构多尺度联合表征方法。实验结果表明所采煤样的孔容和孔比表面积均主要分布在微孔阶段,在0. 6 nm左右时的孔隙孔容量和孔比表面积达到最大,其中微孔容占总孔容的70%以上,微孔孔比表面积占总孔比表面积的99%以上,煤中孔容和孔比表面积分布存在微孔>大孔>介孔的规律。分析构造煤孔隙特征与煤体破坏类型的关系,随煤破坏程度增加,孔容和孔比表面积逐渐增高,大孔孔容比及介孔孔容比逐渐增大,微孔孔容比逐渐减小;孔容增幅主要体现在大孔阶段,比表面积增幅则主要体现在微孔阶段。其中大孔演化主要受控于角砾孔、碎粒孔及摩擦孔等外生孔,介孔演化受控于煤的大分子堆叠结构及分子间距,微孔演化主要受控于煤中芳香层片大小及排列方式。Tectonic coal is generally developed in China because of multi-stage tectonic movement.The pore size distribution scale of tectonic coal is wide(millimeter level-nanometer level),and the pore structure is more complex.The pore structure of different scales controls the process of adsorption-desorption(pore surface),diffusion(nanometer pores)and seepage(micron-millimeter pores)of coalbed methane.Pore structure of different scales is an important factor affecting the storage and migration of CBM.In order to study the distribution characteristics and evolution law of pore structure of tectonic coal with different scales,four kinds of destruction types of coal samples were collected in Lu’an mining area.The pore distribution characteristics of coal samples were tested by pressure mercury method,low temperature N 2 adsorption method and CO 2 adsorption method respectively.The dominant aperture segments of each test method are compared and analyzed.A method of multi-scale joint characterization of microporous structures(<2 nm)by CO 2 adsorption method,mesoporous structure(2-50 nm)by low-temperature N 2 adsorption method,and macroporous structure(>50 nm)by mercury injection method was proposed.The experimental results show that the pore capacity and pore specific surface area of coal are mainly distributed in the micro-pore stage,and the pore capacity and pore specific surface area reach the maximum at about 0.6 nm.Micropore volume accounts for more than 70%of the total pore volume,and micropore specific surface area accounts for more than 99%of the total pore specific surface area.The distribution of pore volume and pore specific surface area in coal has the rule that micropore is larger than macropore and macropore is larger than mesoporous.With the increase of coal damage degree,the pore volume and pore specific surface area gradually increase,the pore volume ratio of large pore and mesoporous pore gradually increase,and the pore volume ratio of micro pore gradually decrease.The increase of pore volume is mainly re

关 键 词：构造煤 孔隙结构 优势孔径 CO2吸附法 低温N2吸附法 压汞法 

分 类 号：TQ531[化学工程—煤化学工程]