考虑煤基质压缩效应的煤全孔径分布特征研究

刘纪坤; 任棒; 王翠霞

doi:10.13272/j.issn.1671-251x.2021060077

考虑煤基质压缩效应的煤全孔径分布特征研究

doi: 10.13272/j.issn.1671-251x.2021060077

西安科技大学安全科学与工程学院, 陕西西安 710054

基金项目:

国家自然科学基金资助项目（51404188）；陕西省教育厅一般专项科学研究计划项目（20JK0773）。

详细信息

作者简介:
刘纪坤(1982-),男,河南濮阳人,副教授,博士,主要研究方向为矿山煤岩动力灾害预防及控制,E-mail:271143890@qq.com。

中图分类号: TD712
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- 被引次数: 0
出版历程
- 收稿日期: 2021-06-29
- 修回日期: 2022-01-28
- 网络出版日期: 2022-03-01

Study on coal full pore aperture distribution characteristics considering coal matrix compression effect

College of Safety Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, China

摘要

摘要: 采用单一煤孔隙结构表征方法只能对某一孔径范围内的孔隙结构进行表征，联合压汞法和低温液氮吸附法可表征煤全孔径分布特征，然而煤基质压缩效应会给孔径分布测量结果带来误差，且目前的研究均未考虑煤基质压缩效应对孔径分布测量结果的影响。为研究不同变质程度煤全孔径分布特征，选取4种煤样进行压汞和低温液氮吸附实验。当汞压为0.124~20 MPa时，煤基质被压缩，孔隙结构发生变形，且随着汞压增加，煤基质压缩效应逐渐明显，孔隙结构变形程度逐渐增加；当汞压为20~206 MPa时，煤基质压缩效应显著，孔隙结构遭到破坏。考虑煤基质压缩效应的影响，提出了一种联孔分析原则：将联孔分界点设定为62.35 nm（汞压为20 MPa时对应的孔径为62.35 nm），当孔径小于62.35 nm时，采用低温液氮吸附法分析孔体积和比表面积；当孔径大于62.35 nm时，结合煤基质压缩性系数对压汞法所测累计进汞体积进行校正来分析孔体积和比表面积。结果表明：微孔和过渡孔对比表面积的贡献最大，中孔及大孔对孔体积的贡献最大；煤样变质程度越大，微孔和过渡孔对比表面积的贡献越大，中孔及大孔对孔体积的贡献越大。
- 煤基质压缩 /
- 全孔径分布 /
- 压汞法 /
- 低温液氮吸附法 /
- 联孔分界点
Abstract: The single pore structure characterization method can only characterize the pore structure within a certain pore aperture range, the combined Mercury intrusion porosimetry and low-temperature liquid nitrogen adsorption method can characterize the full pore aperture distribution characteristics of coal. However, the coal matrix compression effect will bring errors to the pore aperture distribution measurement results, and the current research has not considered the impact of coal matrix compression effect on the pore aperture distribution measurement results. In order to study the full pore aperture distribution characteristics of coal with different metamorphic degrees, Mercury intrusion porosimetry and low-temperature liquid nitrogen adsorption experiments are carried out on four kinds of coal samples. When the mercury pressure is 0.124-20 MPa, the coal matrix is compressed and the pore structure is deformed. With the increase of mercury pressure, the compression effect of coal matrix becomes obvious and the deformation degree of pore structure increases gradually. When the mercury pressure is 20-206 MPa, the compression effect of coal matrix is significant, and the pore structure is destroyed. Considering the impact of coal matrix compression effect, a joint pores analysis principle is proposed. The boundary point of the joint pores is set at 62.35 nm (the corresponding pore aperture is 62.35 nm when the mercury pressure is 20 MPa). When the pore diameter is less than 62.35 nm, the pore volume and specific surface area are analyzed by low-temperature liquid nitrogen adsorption. When the pore aperture is greater than 62.35 nm, the cumulative mercury intrusion volume measured by mercury intrusion method is corrected in combination with the compressibility coefficient of coal matrix so as to analyze the pore volume and specific surface area. The results show that micropore and transition pore contribute the most to the surface area, mesopore and macropore contribute the most to the pore volume. The greater the degree of coal metamorphism, the greater the contribution of micropores and transition pores to the specific surface area, and the greater the contribution of mesopores and macropores to the pore volume.
- coal matrix compression /
- full pore aperture distribution /
- Mercury intrusion porosimetry /
- low-temperature liquid nitrogen adsorption /
- joint pores boundary point

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