低温氮吸附中煤阶对临界填充孔径的影响  

Influence of coal rank on CPSD in low-temperature N_(2) adsorption

作　　者：洪林[1,2] 王文静 高大猛[1,2] 郭英超 马鸿海 HONG Lin;WANG Wenjing;GAO Dameng;GUO Yingchao;MA Honghai(College of Safety Science&Engineering,Liaoning Technical University,Huludao Liaoning 125105,China;Key Laboratory of Mine Thermodynamic Disaster&Control of Ministry of Education,Huludao Liaoning 125105,China)

机构地区：[1]辽宁工程技术大学安全科学与工程学院,辽宁葫芦岛125105 [2]矿山热动力灾害与防治教育部重点实验室,辽宁葫芦岛125105

出　　处：《中国安全科学学报》2022年第4期51-58,共8页China Safety Science Journal

基　　金：国家自然科学基金资助(51004062,51704147)。

摘　　要：为探究煤岩吸附理论及煤层气吸附机制,首先选用6种不同煤阶煤样进行低温氮(N_(2))吸附试验,分析煤中填充态N_(2)分子的临界填充孔径(CPSD);然后通过密度泛函理论(DFT)和微孔填充理论(TVFM)分析试验等温线特征,得到煤中完成微孔填充的临界填充压力(CFP)以及CPSD;最后结合相对压力分段法,通过Langmuir方程-D-A方程-BET方程拟合验证分析结果。研究表明:煤阶由低到高,煤样N_(2)吸/脱附等温线由II型向I型过渡;低阶煤中以微孔填充和单分子层吸附形式赋存的N_(2)分子比例大于高阶煤;煤阶由低到高,CPSD呈先减后增趋势;6种煤样的CPSD在1.61~2.19 nm之间,煤阶越高,CPSD范围越小。In order to study coal adsorption theory and adsorption mechanism of coalbed methane,six coal samples of different ranks were selected for low-temperature N_(2) adsorption experiments to explore CPSD of filled N_(2) molecules in coals.Then,experimental isotherm characteristics were analyzed through density functional theory(DFT)and theory of volume filling of micropore(TVFM),and critical filling pressure(CFP)and CPSD for micropore fillings were obtained.Finally,relative pressure segmentation method was used to verify the results by fitting of Langmuir equation-Dubinin-Astakhov(D-A)equation-Brunauer-Emmet-Teller(BET)equation.The results show that N_(2) adsorption/desorption isotherm of coal samples,from low to high rank,transitions from type II to type I.And proportion of N_(2) molecules present in forms of micropore filling and monolayer adsorption in low-rank coals is greater than that of high-rank ones.CPSD decreases first and then increases as coal rank goes from low to high.The higher the rank is,the smaller CPSD range of 6 coal samples will be,which is between 1.61-2.19 nm.

关 键 词：煤阶 低温N_(2) 吸附试验 临界填充孔径(CPSD) 微孔填充 孔隙结构 

分 类 号：X936[环境科学与工程—安全科学]