水分对不同变质程度煤粒瓦斯扩散系数的影响

Influence of moisture content on gas diffusion coefficient of coal particles with different metamorphic degree

为了研究水分对不同变质程度煤粒瓦斯扩散系数的影响,利用自制设备,对不同煤阶的干燥煤、原煤、湿煤和平衡水煤样进行瓦斯吸附-解吸-扩散实验,分析扩散过程中不同时间段内水分与变质程度两个因素对扩散系数的影响。结果表明:水分的增加,导致瓦斯扩散系数随时间衰减程度变小。寺河矿干燥煤粒和平衡水煤粒在前120min内扩散系数较前5min分别减小了58.75%和53.2%;随着水分的增大,各变质程度煤样的瓦斯扩散系数比值增大。120min内干燥无烟煤扩散系数分别为瘦煤、气肥煤的1.04和2.37倍,平衡水无烟煤扩散系数分别为瘦煤、气肥煤的1.15和2.44倍;随着水分的增加,各煤阶瓦斯扩散系数减小幅度不同,且随着变质程度的减小,扩散系数的减小程度有变大趋势,前5min内随着水分从干燥煤增加到平衡水煤样,扩散系数减小幅度从无烟煤的72.77%增大到了气肥煤的83.49%。

In order to study the effect of moisture content on gas diffusion coefficient of coal particles with different metamorphic degree, the gas absorption, desorption and diffusion process of dry coal, raw coal, wet coal and equilibrium water coal samples with different coal ranks were experimental studied by using the self-made instrument. The influence of moisture content and metamorphic degree on diffusion coefficient in different period of diffusion process was analyzed. The results showed that the increase of moisture content leads to the attenuation degree of gas diffusion coefficient with time becoming smaller. The diffusion coefficients of dry and equilibrium water coal samples from Sihe coal mine decrease by 58.75% and 53.2% respectively in 120 min comparing with that in 5 min. With the increase of moisture content, the gas diffusion coefficient ratio of each coal sample with different metamorphic degree increases. The diffusion coefficient of dry anthracite is 1.04 and 2.37 times of lean coal and gas fat coal respectively in 120 min, and the diffusion coefficient of equilibrium water coal is 1.15 and 2.44 times of lean coal and gas fat coal respectively. The decrease range of gas diffusion coefficient with different metamorphic degree is different with increase of moisture content, and the decrease degree of diffusion coefficient has an enlarging trend with the decrease of metamorphic degree. The decrease range of diffusion coefficient increases from 72.77% of anthracite to 83.49% of gas fat coal with the moisture content increase from dry coal to equilibrium water coal in the first 5 min.