中国安全科学学报 ›› 2022, Vol. 32 ›› Issue (4): 51-58.doi: 10.16265/j.cnki.issn1003-3033.2022.04.008

• 安全工程技术 • 上一篇    下一篇

低温氮吸附中煤阶对临界填充孔径的影响

洪林1,2(), 王文静1,2, 高大猛1,2, 郭英超1,2, 马鸿海1,2   

  1. 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
  • 收稿日期:2022-01-09 修回日期:2022-03-11 出版日期:2022-04-28
  • 作者简介:

    洪林 (1976—),男,重庆人,博士,副教授,主要从事煤矿瓦斯灾害防治研究及教学工作。E-mail:

    高大猛, 讲师。

  • 基金资助:
    国家自然科学基金资助(51004062); 国家自然科学基金资助(51704147)

Influence of coal rank on CPSD in low-temperature N2 adsorption

HONG Lin1,2(), WANG Wenjing1,2, GAO Dameng1,2, GUO Yingchao1,2, MA Honghai1,2   

  1. 1 College of Safety Science & Engineering, Liaoning Technical University, Huludao Liaoning 125105, China
    2 Key Laboratory of Mine Thermodynamic Disaster & Control of Ministry of Education, Huludao Liaoning 125105,China
  • Received:2022-01-09 Revised:2022-03-11 Published:2022-04-28

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(N2)吸附试验,分析煤中填充态N2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N2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N2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。

关键词: 煤阶, 低温N2, 吸附试验, 临界填充孔径(CPSD), 微孔填充, 孔隙结构

Abstract:

In order to study coal adsorption theory and adsorption mechanism of coalbed methane, six coal samples of different ranks were selected for low-temperature N2 adsorption experiments to explore CPSD of filled N2 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 N2 adsorption/desorption isotherm of coal samples, from low to high rank, transitions from type II to type I. And proportion of N2 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.

Key words: coal rank, low-temperature N2, adsorption experiment, critical filling pore size distribution (CPSD), micropore filling, pore structure