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水分是含瓦斯煤粒扩散规律的重要影响因素之一,运用自制设备,试验研究当水分小于等于平衡水时,3种变质程度煤样的瓦斯扩散量、扩散速度和扩散系数随水分、扩散时间的变化规律;基于气体在多孔介质内的吸附解吸理论和Fick扩散定律,分析水分对瓦斯在煤粒内扩散动力参数和动态过程的影响机理。结果表明,在不大于煤样平衡水分条件下,高、中、低变质程度煤样的瓦斯极限扩散量、解吸速度和瓦斯扩散系数随水分增加而显著降低,同一种变质程度干燥煤样的瓦斯扩散系数基本是平衡水分煤样的3~5倍;水分的增加降低了煤粒内的瓦斯初始质量浓度和扩散系数,进而大幅度降低了瓦斯扩散速度;水分子更容易占据煤基质表面吸附位,致使煤对瓦斯的吸附量减少,水分子在煤粒内表面发生多层吸附,而堵塞部分的瓦斯分子在煤粒内表面扩散,缩小了扩散通道,增大了瓦斯扩散阻力,导致含瓦斯煤粒的瓦斯扩散系数减小。
Moisture is one of the important factors that affect the law of coal particle diffusion. Using homemade equipment, when the water content is less than or equal to that of equilibrium water, the gas diffusion, diffusion rate and diffusion coefficient of coal samples with three kinds of metamorphism vary with the water content, diffusion time Based on the adsorption and desorption theory of gas in porous media and the Fick diffusion law, the influence mechanism of moisture on the dynamic parameters and dynamic process of gas diffusion in coal particles was analyzed. The results show that the gas diffusion limit, desorption rate and gas diffusion coefficient of coal samples with high, medium and low degree of metamorphism are obviously decreased with the increase of water content under the condition of no more than coal-like equilibrium moisture. The diffusion coefficient is basically 3 to 5 times that of the balanced moisture coal sample; the increase of water content reduces the initial gas mass concentration and diffusion coefficient of coal gas within the coal particle, thus greatly reducing the gas diffusion rate; water molecules more easily occupy the surface adsorption sites , Resulting in the reduction of coal gas adsorption, water molecules in the multi-layer surface adsorption of coal particles, while the blockage of the gas molecules in the coal surface diffusion, reducing the diffusion channels, increasing the gas diffusion resistance, resulting in gas Coal gas diffusion coefficient decreases.