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李冰, 陈锋, 姜沛汶, 任建刚, 刘见宝, 宋志敏. 冲击荷载作用下不同煤阶煤的结构演化特征研究[J]. 煤炭科学技术, 2021, 49(10): 217-227.
引用本文: 李冰, 陈锋, 姜沛汶, 任建刚, 刘见宝, 宋志敏. 冲击荷载作用下不同煤阶煤的结构演化特征研究[J]. 煤炭科学技术, 2021, 49(10): 217-227.
LI Bing, CHEN Feng, JIANG Peiwen, REN Jiangang, LIU Jianbao, SONG Zhimin. Study on structure evolution features of different rank coals under shock load[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(10): 217-227.
Citation: LI Bing, CHEN Feng, JIANG Peiwen, REN Jiangang, LIU Jianbao, SONG Zhimin. Study on structure evolution features of different rank coals under shock load[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(10): 217-227.

冲击荷载作用下不同煤阶煤的结构演化特征研究

Study on structure evolution features of different rank coals under shock load

  • 摘要: 瓦斯的高效抽采和合理利用对于防治煤矿瓦斯灾害、改善空气质量和增加清洁能源供应都具有十分重要的意义。为探讨冲击荷载对煤体的微观孔隙结构和大分子形态学结构的影响,以褐煤(HM)、烟煤(YM)和无烟煤(WY)为研究对象,利用分离式霍普金森压杆(Separated Hopkinson Pressure Bar,SHPB)冲击试验系统模拟冲击应力在不同衰减过程中的冲击波和应力波,结合低温液氮和拉曼光谱测试数据,研究了冲击荷载作用下不同煤阶煤的结构演化特征和规律。结果表明,在冲击荷载的作用下,褐煤、烟煤和无烟煤的液氮总吸附量、总比表面积和总孔体积都减小(例如,在冲击荷载分别为0、0.5、0.75和1.0 MPa时,HM-0、HM-1、HM-2和HM-3的BJH总比表面积分别为7.066、6.611、4.468和3.548 m2/g),微孔均逐渐向过渡孔或中孔转化,微孔的占比减小,而过渡孔和中孔的占比之和增大。冲击荷载可以促进微孔中吸附的瓦斯有效解吸,提高过渡孔和中孔中瓦斯的扩散和渗流速度,很好地解释了煤储层在外载扰动的过程中会产生超量煤层气这一宏观现象。随着冲击荷载的逐渐增大,不同煤阶煤拉曼光谱D1峰的峰位置逐渐向高波数移动,G峰的峰位置逐渐向低波数移动,ID1/IG逐渐增大,且冲击荷载后不同煤阶煤的ID3/Itotal均较原始煤样所有减小。这表明,冲击荷载导致不同煤阶煤大分子形态学结构中微晶结构单元的破坏,微晶生长程度向无序化方向升高的方向发展,大分子内缺陷程度逐渐增加,无定形碳的相对量减少。

     

    Abstract: The efficient extraction and rational utilization of gas are of great significance for preventing and controlling the gas disaster,improving the air quality and increasing the supply of clean energy. In order to explore the influence of shock load on the microscopic pore structure and macromolecular morphological structure of coal,the lignite,bitumite and anthracite were taken as the research objects,and the Separated Hopkinson Pressure Bar (SHPB) impact test system was used to simulate the shock wave and stress wave of impact stress in the different attenuation processes. Combined with the test data of low temperature liquid nitrogen and Raman spectra,the characteristics and laws of structural evolution of different rank coals under the shock load were studied. The results showed that the total adsorption capacities,total specific surface areas and total pore volumes of lignite,bitumite and anthracite decreased under the effect of shock load. For example,when the shock load were 0,0.5,0.75 and 1.0 MPa,the total BJH specific surface areas of HM-0,HM-1,HM-2 and HM-3 were 7.066,6.611,4.468 and 3.548 m2/g,respectively. The micropores were gradually transformed into transition pores or mesopores,and the proportion of micropores decreased,while the sum of the proportion of transitional pores and mesopores increased. The shock load could promote the effective desorption of gas adsorbed in micropores and improve the diffusion and seepage velocity of gas in transitional pores and mesopores,which could well explain the macroscopic phenomena of the produce of excess coalbed methane in the process of disturbance in coal reservoir. With the increase of the shock load,the D1 peak positions of Raman spectrum for different rank coals gradually moved to the high wave number,the G peak positions gradually moved to the low wave number,and the ID1/IG gradually increased. After the shock load,the ID3/Ito tal of different rank coals decreased compared with the original coal sample. This suggestted that the shock load leaded to the destruction of the microcrystalline structure units in the macromolecular morphological structure of different rank coals,and the degree of microcrystalline growth increased towards the direction of disorder. The degree of intramolecular defects gradually increased,and the relative amount of amorphous carbon also decreased.

     

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