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针对煤层瓦斯抽采过程中吸附瓦斯难以解吸的技术难题,提出可控源微波场促进煤层瓦斯解吸的新思路,采用可控源微波场作用下煤岩瓦斯解吸试验装置,研究有、无可控源微波场作用下煤体中甲烷的解吸规律,探讨可控源微波场对煤体中甲烷解吸特性的影响机理。研究结果表明,可控源微波场能够促进煤体中甲烷的解吸,使煤体的甲烷解吸速率增大且解吸后期衰减变慢、累计甲烷解吸量增加1.65~3.79倍;有、无可控源微波场作用下煤体的甲烷解吸动力学曲线形态基本一致,且能用动扩散系数模型较好地描述;相同解吸时间条件下,可控源微波场作用下煤体的甲烷扩散系数比无微波场作用时大。可控源微波场对煤体中甲烷解吸特性的影响机理主要在于可控源微波场能够增强煤体中甲烷分子的活性、提高煤体的甲烷扩散系数、改变甲烷解吸过程中煤体的扩散阻力级差,使煤体中甲烷的解吸速度增加、扩散速度加快、扩散阻力减小,从而有利于促进煤体中甲烷的解吸。
Aimed at the technical difficulty of desorption of adsorbed gas during gas drainage in coal seam, a new idea of controllable source microwave field to promote gas desorption in coal seam is put forward. The coal gas desorption test device under controlled microwave field is studied. The desorption of methane in coal under the action of source microwave field and the mechanism of controllable source microwave field on desorption of methane in coal. The results show that the controllable source microwave field can promote the desorption of methane in coal, increase the desorption rate of methane in coal and slow the desorption in the late stage, and the cumulative desorption amount of methane increases by 1.65 ~ 3.79 times; there is no controllable source Under the action of microwave field, the kinetic curves of methane desorption of coal are basically the same, and can be well described by dynamic diffusion coefficient model. Under the same desorption time, the methane diffusion coefficient of coal under controlled microwave field is lower than that without microwave Field role when large. Controllable source microwave field on coal desorption characteristics of methane is mainly due to the mechanism of controlled source microwave field can enhance the activity of methane in coal, improve the methane diffusion coefficient of coal, methane desorption process to change the diffusion resistance Grades, so that the rate of desorption of methane in coal increased, the proliferation of speeding up, reducing the diffusion resistance, which is conducive to promoting the desorption of methane in coal.