模拟CO2埋藏不同煤级煤孔隙结构变化实验研究  

Simulation Experiment on the Changes of Pore Structure in Different Ranks Coals During the CO_2 Geosequestration

作　　者：刘长江[1,2] 桑树勋[1] WANG Guo-xiong RUDOLPH Victor 

机构地区：[1]中国矿业大学资源与地球科学学院煤层气资源与成藏过程教育部重点实验室,江苏徐州221116 [2]School of Chemical Engineering, The University of Queensland, QLD 4072, Australia

出　　处：《中国矿业大学学报》2010年第4期496-503,共8页Journal of China University of Mining & Technology

基　　金：国家高技术研究发展计划(863)项目(2007AA06Z220);教育部科学技术研究重大项目(307014)

摘　　要：使用高压超临界CO2地球化学反应器在实验室模拟CO2在地下煤层的埋藏过程,反应器中的温度为40℃,压力为9.8MPa,反应时间为72h,通过氦比重仪和压汞仪对不同煤级煤的孔隙结构变化进行了研究.结果表明:经过超临界CO2-H2O的作用后,无烟煤的真密度从1.51g/cm3增加到1.59g/cm3,其余几种煤真密度变化不大,视密度均有减小趋势,其中褐煤和瘦煤减小幅度为0.1g/cm3;褐煤总孔容变化最大,增加主要表现在大孔阶段,增幅为85%,孔隙度增幅达118%,其余煤种的总孔容和孔隙度也有不同程度增高.CO2的埋藏过程对中低煤级的影响主要是其大中孔,而对高煤级主要影响其微孔发育,无烟煤微孔孔容的增大使得煤的表面积进一步增大,从未处理的24.3m2/g增加到27.6m2/g,从而对气体的吸附能力将越来越强;对退汞曲线的滞后性分析表明,CO2的埋藏过程对"墨水瓶"孔隙度将产生一定的影响.A high pressure supercritical CO2 geochemical reactor was used to simulate the CO2 sequestration process into deep coal seam under around 40 ℃ and 9.8 MPa for 72 hours.The changes of pore structure of different rank coal samples with and without the supercritical CO2 treatment were investigated by helium pycnometer and mercury porosimetry.The results show that the true density of anthracite increase from 1.51 g/cm^3 to 1.59 g/cm^3 while that of other rank samples have no significant changes after being treated by the HP-ScCO2-H2O system.All the bulk densities decrease,of which lignite and low volatile bituminous decreased by 0.1 g/cm^3.The growth rate of total pore volume and porosity of lignite are 85% and 118% respectively,which are mainly attributed to the increase in macropores.Pore structures of coal during CO2 sequestration are mainly influenced by macropores and mesopores in low rank coals,while in high rank coals mainly by micropores,which increase the surface area of coal.As shown in anthracite,the surface area increase from 24.3 m^2/g to 27.6 m^2/g,which accordingly enhance the gas adsorption.The ＂ink-bottle＂ pores are influenced during CO2 sequestration process from analysis on hysteresis of the extrusion curves.

关 键 词：煤 CO2地质埋藏 超临界CO2-H2O-煤作用 孔隙结构 

分 类 号：P618.11[天文地球—矿床学]