可控源微波场促进煤体中甲烷解吸的试验研究

 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。

Experimental study on desorption enhancing of methane in coal mass using a controlled microwave field

The controlled microwave field(CMF) is proposed in this paper to address the technical challenge posed by the difficulty in desorption of adsorbed gas during the extraction of coal bed methane. The study on the desorption of methane in coal mass with and without the CMF action was conducted with the gas desorption system with CMF developed in-house. The mechanism of influence of the CMF on the desorption characteristics of methane in coal mass is investigated. It was proved by the experiments that the CMF enhanced the desorption of methane in coal mass and enabled a significant increase in the desorption rate of methane in the coal with the attenuation slowdown. The accumulated amount of methane desorption was increased by 1.65 up to 3.79 times. The shapes of the kinetic curve for the desorption of methane in coal mass remain consistent with or without the CMF action，which may be better depicted by the dynamic diffusion coefficient model. During the same desorbing time，the diffusion coefficient of methane in the coal mass with the CMF action is greater than that of methane without. The CMF may enhance the molecular activity and increase the diffusion coefficient of methane in the coal mass. It alters the differential diffusion resistance of the coal mass during the desorption of methane，thus enables the increase in the desorption and diffusion rate of methane in the coal mass with the decreased diffusion resistance，which promote the desorption of methane in the coal mass.