新疆阜康矿区低阶煤吸附孔特征与瓦斯放散性能实验研究

发布时间：2018-03-20 01:18

本文选题：低阶煤　切入点：吸附孔　出处：《西安科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：新疆地区煤炭资源含量丰富,煤层条件复杂,阜康矿区作为其煤炭的重要生产基地之一,资源条件优越,具有广阔的煤层气开发前景。研究阜康矿区低阶煤的吸附孔特征和瓦斯放散性能,以及吸附孔特征对瓦斯放散性能的影响关系,能够为矿井生产过程中的瓦斯灾害防治和煤层气抽采利用提供基础依据。本文选取新疆阜康矿区八个典型矿井的主采煤层煤样进行实验研究,实验煤样宏观物理性质基本相似。通过煤样的工业分析实验和显微组分分析实验,分别得到煤样的化学组分特征和显微组分特征,依据其挥发分质量比和镜质组平均最大反射率可知煤样变质程度均较低。对煤样进行低温氮吸附实验测试,测得吸附量随相对压力的变化关系即为实验煤样的吸附等温线,依据吸附等温线形态可知实验煤样吸附孔以一端开口的圆筒形孔和一端封闭的平板形孔为主。根据气体吸附理论,采用相应的模型计算煤样的平均孔隙直径和孔径分布特征等结构特征参数。分析结果表明,煤样吸附孔的比表面积以过渡孔为主,孔隙体积以过渡孔和中孔为主。根据吸附量和相对压力的关系,利用FHH模型计算煤样的吸附孔表面分形维数,结果表明实验煤样在研究尺度范围内分形特征明显,煤样的化学组分和吸附孔结构参数等均对吸附孔分形维数的大小有一定影响。通过煤样的瓦斯放散初速度实验,得到煤样的瓦斯放散初速度和放散量,利用Knudsen数判断实验煤样吸附孔内的瓦斯放散模式。通过拟合分析可知,煤样的瓦斯放散初速度与孔隙结构特征参数和分形维数均存在一定的线性关系。实验范围内10s时固定空间内的瓦斯放散量与吸附孔结构特征参数和分形维数均无明显线性关系,60 s时固定空间内的瓦斯放散量与吸附孔平均孔隙直径呈线性正相关,与吸附孔表面分形维数呈线性负相关,与吸附孔比表面积和体积无明显线性关系。
[Abstract]:Xinjiang is rich in coal resources and complicated in coal seam conditions. As one of the important coal production bases, Fukang mining area has superior resource conditions. This paper studies the characteristics of adsorption hole and gas release of low-rank coal in Fukang mining area, and the relationship between the characteristics of adsorption hole and gas emission. It can provide the basis for gas disaster prevention and coalbed methane extraction and utilization during mine production. This paper selects coal samples from eight typical coal mines in Fukang mining area, Xinjiang, to carry out experimental research. The macroscopic physical properties of experimental coal samples are basically similar. The chemical and maceral characteristics of coal samples are obtained by industrial and maceral analysis experiments. According to the mass ratio of volatile matter and the average maximum reflectance of vitrinite, the metamorphic degree of coal sample is low. According to the adsorption isotherm morphology, the experimental coal sample adsorption holes are mainly cylindrical holes with one end opening and flat plate holes with one end closed. According to the gas adsorption theory, The structural parameters such as average pore diameter and pore size distribution characteristics of coal samples are calculated by using the corresponding model. The results show that the specific surface area of adsorption pores of coal samples is mainly transition pore. The pore volume is mainly transition pore and mesopore. According to the relation between adsorption quantity and relative pressure, the fractal dimension of adsorption pore surface of coal sample is calculated by FHH model. The results show that the fractal characteristics of experimental coal sample are obvious in the study scale. The chemical composition of coal sample and the structure parameters of adsorption pore have certain influence on the fractal dimension of adsorption pore. The Knudsen number is used to judge the gas release model in the adsorption hole of the experimental coal sample. There is a linear relationship between the initial velocity of gas release and the characteristic parameters of pore structure and fractal dimension. There is no relationship between the gas emission and the characteristic parameters and fractal dimension of the pore structure in the fixed space of 10 s in the experimental range. There is a linear positive correlation between the amount of gas emission in the fixed space and the average pore diameter of the adsorption pore at 60 s. There is a linear negative correlation with the fractal dimension of the adsorption pore surface, but no obvious linear relationship with the specific surface area and volume of the adsorption pore.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712

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