李娜娜,刘会虎,桑树勋. 基于压汞-低温液氮联孔与核磁共振分析的煤中孔径分布对比研究[J]. 煤矿安全,2024,55(2):1−9. doi: 10.13347/j.cnki.mkaq.20230344
    引用本文: 李娜娜,刘会虎,桑树勋. 基于压汞-低温液氮联孔与核磁共振分析的煤中孔径分布对比研究[J]. 煤矿安全,2024,55(2):1−9. doi: 10.13347/j.cnki.mkaq.20230344
    LI Nana, LIU Huihu, SANG Shuxun. Comparative study on pore size distribution in coal based on mercury intrusion-low temperature liquid nitrogen combined pore and nuclear magnetic resonance analysis[J]. Safety in Coal Mines, 2024, 55(2): 1−9. doi: 10.13347/j.cnki.mkaq.20230344
    Citation: LI Nana, LIU Huihu, SANG Shuxun. Comparative study on pore size distribution in coal based on mercury intrusion-low temperature liquid nitrogen combined pore and nuclear magnetic resonance analysis[J]. Safety in Coal Mines, 2024, 55(2): 1−9. doi: 10.13347/j.cnki.mkaq.20230344

    基于压汞-低温液氮联孔与核磁共振分析的煤中孔径分布对比研究

    Comparative study on pore size distribution in coal based on mercury intrusion-low temperature liquid nitrogen combined pore and nuclear magnetic resonance analysis

    • 摘要: 煤中孔隙结构测量常用压汞法、低温液氮法和核磁共振法,因不同方法的原理和测试范围不同,导致结果无法统一使用,且压汞法中基质压缩效应会造成较大误差;为解决该问题,以沁水盆地晋城和长治矿区的3个高阶煤样为例,利用压汞、低温液氮吸附及核磁共振驰豫法分别测试煤样的孔隙结构,通过对压汞数据进行压缩性校正,与低温液氮数据在衔接孔径处拼接,对煤的孔隙结构进行了联合表征,并结合核磁共振对比分析了煤的孔径分布特征。结果表明:压汞数据校正后孔体积与低温液氮的结果更接近,偏差值在22.40%~38.51%;不同煤样采用联孔法进行孔隙结构分析的联孔位置在75~89 nm之间;联孔法煤样孔容积为0.001 36~0.004 58 cm3/g,不同孔径孔容比例表现为过渡孔>大孔>中孔>微孔;与单一测试方法相比,联孔法与核磁共振法孔径分布更为接近,但同时也存在差异,联孔法表征的微孔、过渡孔、中孔和大孔平均分布比例分别为8.68%、45.58%、20.54%和25.20%,核磁法微孔、过渡孔、中孔和大孔平均分布比例分别为10.64%、64.21%、14.23%和10.92%,结果差异原因可能主要与压汞法、低温液氮法加压改变了煤的孔隙结构有关;通过核磁共振结果对比,联合校正后的压汞与低温液氮数据可提高煤中孔径分布测试结果的准确性。

       

      Abstract: The pore structure measurement in coal is commonly analyzed by mercury intrusion method, low temperature liquid nitrogen method and nuclear magnetic resonance method. Due to the different test methods, the results cannot be used uniformly, and the matrix compression effect in mercury intrusion method will cause large errors. In order to solve this problem, three high-rank coal samples from Jincheng and Changzhi Mining Areas in Qinshui Basin were taken as examples, and used mercury injection, low-temperature liquid nitrogen adsorption and nuclear magnetic resonance relaxation methods to test the pore structure of coal samples respectively. Through the compressibility correction of mercury injection data and splicing with low-temperature liquid nitrogen data at the connection aperture, the pore structure of coal was characterized by joint characterization, and the pore size distribution characteristics of coal were compared and analyzed in combination with nuclear magnetic resonance. The results show that the pore volume corrected by mercury intrusion data is closer to that of low temperature liquid nitrogen, and the deviation value is 22.40%-38.51%; the pore structure of different coal samples is analyzed by the joint pore method, and the position of the joint pore is between 75-89 nm; the results show that the pore volume of coal samples is 0.001 36-0.004 58 cm3/g, and the pore volume ratio of different pore sizes is transition pore>macropore>mesopore>micropore; compared with the single test method, the pore size distribution of the combined pore method and the nuclear magnetic resonance method is closer, but there are also differences. The average distribution ratios of micropores, transition pores, mesopores and macropores characterized by the combined pore method are 8.68%, 45.58%, 20.54% and 25.20%, respectively. The average distribution ratios of micropores, transition pores, mesopores and macropores characterized by the nuclear magnetic resonance method are 10.64%, 64.21%, 14.23% and 10.92%, respectively. The reason for the difference may be mainly related to the pore structure of coal changed by mercury intrusion method and low temperature liquid nitrogen method; through the comparison of NMR results, it is found that the combined corrected mercury injection and low temperature liquid nitrogen data can improve the accuracy of the pore size distribution test results in coal.

       

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