程晓茜, 田继军, 王海超, 张玉垚, 郝慧丽, 张治恒. H2S水溶液对低阶煤孔隙结构影响的实验研究[J]. 煤炭学报, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0417
引用本文: 程晓茜, 田继军, 王海超, 张玉垚, 郝慧丽, 张治恒. H2S水溶液对低阶煤孔隙结构影响的实验研究[J]. 煤炭学报, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0417
CHENG Xiaoqian, TIAN Jijun, WANG Haichao, ZHANG Yuyao, HAO Huili, ZHANG Zhiheng. Experimental research on the effect of H2 S solution on pore structure of low-rank coal[J]. Journal of China Coal Society, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0417
Citation: CHENG Xiaoqian, TIAN Jijun, WANG Haichao, ZHANG Yuyao, HAO Huili, ZHANG Zhiheng. Experimental research on the effect of H2 S solution on pore structure of low-rank coal[J]. Journal of China Coal Society, 2020, 45(4). DOI: 10.13225/j.cnki.jccs.2019.0417

H2S水溶液对低阶煤孔隙结构影响的实验研究

Experimental research on the effect of H2 S solution on pore structure of low-rank coal

  • 摘要: 基于新疆诸多低阶煤矿(井)区煤层、煤系水中硫化氢(H2S)含量较高的特殊地质现象,以沙尔湖煤矿低阶煤为研究对象,采用样品制备—酸化前高压压汞和场发射扫描电镜实验—H2S水溶液配置—样品浸泡酸液—酸化后高压压汞和场发射扫描电镜实验的实验步骤,物理模拟了H2S水溶液与煤岩体的酸化作用过程,对比研究了H2S水溶液酸化前后低阶煤孔隙结构的变化规律。研究表明:H2S水溶液酸化后煤样孔隙体积增大,增幅达23.09%,其中大孔体积增幅达66.10%,中孔体积增大4.86%,孔隙连通性明显改善;酸化前后孔隙类型均以开放孔为主,酸化后开放孔体积明显增大,增幅达21.18%;酸化前后总孔比表面积变化不大,微孔和过渡孔的孔比表面积增幅分别为0.42%和1.37%,大孔的孔比表面积增大60.00%;H2S水溶液酸化后,热力学模型的分形维数减小,表明孔隙表面变平滑,Menger海绵模型的分形维数增大,表明煤样孔隙空间形态及结构变复杂。H2S水溶液对煤孔隙结构的改善机理主要体现在两个方面:一方面是酸化作用引起碳酸盐岩类矿物与酸液发生溶蚀作用,导致充填于孔隙中的碳酸盐类矿物被溶蚀,从而产生孔隙体积增大的正效应;另一方面是酸化作用导致煤中黏土矿物等膨胀、分散,生成的细小颗粒堵塞孔隙,造成孔隙体积减小的负效应。但总体上溶蚀作用产生的正效应大于堵塞孔隙产生的负效应,从而使得H2S水溶液酸化后总孔隙体积增大,孔隙连通性得以改善。

     

    Abstract: Based on the special geological phenomena that the high concentration of hydrogen sulfide (H2 S) exists in coal seam and coal measure water in many low-rank coal mining areas in Xinjiang,the low-rank coal of Shaerhu coal mine was taken as the basic study object. The experimental procedure consists of coal samples preparation,high pres- sure mercury injection porosimetry ( HPMIP ) and field emission scanning electron microscope ( FESEM) before acidization,H2 S solution preparation, sample solution immersion and HPMIP and FESEM after acidization. The acidization of the H2 S solution and coal was physically simulated,and the dynamic change of pore structure before and after H2 S solution acidizing was studied in detail. The results show that after the H2 S solution acidizing,the total pore volume of coal increased by 23. 09% ,the macropore volume increased substantially by 66. 10% and the mesopore vol- ume increased by 4. 86% ,which indicated that the pore connectivity was significantly improved. The pore types before and after acidization were dominated by open pores,and the open pores volume increased significantly by 21. 18% af- ter acidization. The change of total pore specific surface area was not obvious before and after acidization,the increase of pore specific surface area of micro- and transition pores were 0. 42% and 1. 37% respectively,and the increase of pore specific surface area of macropores was 60. 00% . After the H2 S solution acidizing,the fractal dimensions of ther- mal model decreased which demonstrated that the pore surface became smoother, while fractal dimensions of the Menger sponge model increased which demonstrated that the pore space morphology and structure became more com- plex. The improvement mechanism of the H2 S solution on coal pore structure is mainly derived from the following two aspects:the positive effect caused by the dissolution of carbonate minerals in the coal,which increase the pore volume; the negative effect caused by clay minerals which can disperse,expand,and precipitate into the pores,that reduce the connectivity of the pores. However,the effect of positive effect was larger than the negative effect,indicating the total pore volume of coal increased and the pore connectivity improved. after acidization was compared and analyzed,and the improvement mechanism of coal pore structure was also revealed. The research results are helpful to reveal the cor- relation between the high concentration of H2 S and high CBM production.

     

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