微波场作用对煤的瓦斯吸附解吸特性影响的实验研究

发布时间：2018-06-01 00:46

本文选题：微波场作用 + 吸附　；参考：《中国矿业大学》2015年硕士论文

【摘要】：预抽煤层瓦斯是矿井瓦斯灾害防治的有效方法之一,然而我国大部分煤层透气性低、吸附瓦斯含量较高,使得煤层瓦斯抽采率普遍较低。因此,要想提高煤层瓦斯的抽采率就必须解决如何增加煤层透气性、促进煤体介质内微孔的吸附瓦斯解吸、加速自由瓦斯的扩散的问题。根据电磁场对煤层瓦斯吸附解吸的影响特性,提出了微波场作用减小煤层瓦斯吸附、促进煤层瓦斯解吸的新思路。本文通过开展微波场作用对煤层瓦斯吸附解吸特性影响的理论分析以及微波场作用对煤的孔隙结构以及吸附解吸特性影响的实验研究,得到了不同微波场条件下煤的孔隙结构和吸附解吸特性的变化规律,并分析了微波场作用对煤的孔隙结构及吸附解吸特性的影响机制,取得了如下研究结论:(1)微波场作用能够使煤样的比表面积和微孔孔容减小。(2)微波场作用后,煤样的Langmuir常数a减小,且随着微波场作用时间的增加,Langmuir常数a的变化不明显,大体上为先减小、后轻微增大、再逐渐减小的趋势;而吸附常数b的变化趋势则相反,但与吸附等温曲线的曲率的变化趋势一致。(3)不同功率条件下微波场作用后的煤样的甲烷吸附曲线的变化趋势基本一致,且微波场作用改变了煤对甲烷的吸附能力,使煤样的甲烷吸附量比无微波场作用的煤样要小。(4)无微波场作用和微波场作用后的煤样的甲烷放散特征曲线形式一致。在甲烷吸附量减少的情况下煤样的甲烷放散速度略有增大或保持相同水平,表明微波场作用后的煤样的甲烷放散能力有所增加。(5)微波场作用对煤体的孔隙结构及瓦斯吸附解吸特性的影响机制主要表现为微波场对煤体的电磁辐射热效应与损伤效应的综合作用。(6)随着微波场作用时间的增加,可以将煤样的瓦斯吸附特性的变化过程分为三个阶段。
[Abstract]:Pre-drainage of coal seam gas is one of the effective methods to prevent and cure mine gas disaster. However, the gas permeability of most coal seams in China is low and the content of adsorbed gas is high, which makes the coal seam gas extraction rate generally lower. Therefore, in order to improve the coal seam gas extraction rate, it is necessary to solve the problem of how to increase the permeability of coal seam, promote the adsorption gas desorption in the medium of coal body, and accelerate the diffusion of free gas. According to the influence of electromagnetic field on coal seam gas adsorption and desorption, a new idea of reducing coal seam gas adsorption by microwave field and promoting coal seam gas desorption is put forward. In this paper, the influence of microwave field on the adsorption and desorption characteristics of coal seam gas is analyzed theoretically, and the effect of microwave field on the pore structure and adsorption desorption characteristics of coal is studied experimentally. The changes of pore structure and adsorption and desorption characteristics of coal under different microwave fields are obtained, and the mechanism of the influence of microwave field on the pore structure and adsorption desorption characteristics of coal is analyzed. The following conclusions are obtained: (1) the microwave field can reduce the specific surface area and pore volume of coal samples.) the Langmuir constant a of coal samples decreases with the increase of microwave field time, and the change of the Langmuir constant a is not obvious with the increase of microwave field time. In general, it decreases first, then increases slightly, then decreases gradually, while the adsorption constant b changes in the opposite direction. However, the change trend of methane adsorption curve of coal samples under microwave field is basically the same as that of the curvature of adsorption isotherm curve, and the adsorption ability of coal to methane is changed by microwave field. The methane adsorption capacity of coal sample is smaller than that of coal sample without microwave field. The methane emission rate of the coal sample increases slightly or keeps the same level when the methane adsorption capacity decreases. The results show that the methane emission ability of coal samples after microwave field is increased. 5) the mechanism of the effect of microwave field on the pore structure and gas adsorption and desorption characteristics of coal is as follows: the effect of microwave field on the thermal effect of electromagnetic radiation on coal body and its mechanism of gas adsorption and desorption. With the increase of the time of microwave field action, The change of gas adsorption characteristics of coal samples can be divided into three stages.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD712.7

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