含水率对构造煤煤粒瓦斯扩散的影响研究

Study on influence of water content on gas diffusion of tectonic coal particles

为了研究分析不同含水率对煤粒瓦斯扩散的影响,以平煤八矿构造煤为研究对象,利用瓦斯扩散试验装置,测定不同含水率条件下煤粒瓦斯解吸量,对比分析不同扩散模型,优选适合描述含水煤粒瓦斯解吸全过程的扩散模型,进而研究不同含水率对煤粒瓦斯扩散系数的影响。研究结果表明:相同时段下,干燥煤样的累计瓦斯解吸量最大,随着含水率增加煤样的累计瓦斯解吸量越来越小,水分的增加封堵了瓦斯扩散通道,在煤微孔隙内产生一定的蒸气压增大了瓦斯扩散的阻力使得单位时间内的瓦斯解吸量不断减小;通过3种扩散模型的对比发现幂函数模型在误差大小和稳定性方面都优于其他2种模型;利用该幂函数模型对扩散系数进行计算得出4种含水率对煤粒扩散系数的影响发现,扩散系数均经历前期快速下降和后期缓慢下降2个阶段,扩散系数随含水率的增大而减小且扩散速率趋于稳定。

In order to analyze the influence of different water contents on the gas diffusion of coal particles,taking the tectonic coal in No.8 coal mine of Pingmei as the study object,the gas desorption amount of coal particles under different water contents were measured by using the gas diffusion test device.Different diffusion models were compared and analyzed,and the diffusion model being suitable to describe the whole process of gas desorption of water-containing coal particles was selected with optimization,then the influence of different water contents on the gas diffusion coefficient of coal particles was studied.The results showed that under the same time period,the cumulative gas desorption amount of the dried coal sample was the largest,and the cumulative gas desorption amount of the coal sample decreased with the increase of water content.The increase of water blocked the gas diffusion path,which generated a certain vapor pressure in the micropores of coal,so the resistance of gas diffusion increased,and the gas desorption amount per unit time reduced continuously.Through the comparison of three diffusion models,it showed that the power function model was superior to the other two models in the error size and stability.The influence of four kinds of water content on the diffusion coefficient of coal particles was obtained through the calculation of diffusion coefficient by using the power function model,which showed that all the diffusion coefficients underwent two stages,namely the rapid decline in the early period and the slow decline in the later period.The diffusion coefficient decreased with the increase of water content,and the diffusion rate tended to be stable.