Characteristics of Seepage and Diffusion in Gas Drainage and Its Application for Enhancing the gas utilization rate
Characteristics of Seepage and Diffusion in Gas Drainage and Its Application for Enhancing the gas utilization rate
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DOI：
10.1007/s11242-021-01573-7
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发表时间：
2021-03
影响因子：
2.7
通讯作者：
Minghao Yi;Liang Wang;Qingquan Liu;Congmeng Hao;Zhenyang Wang;Peng Chu
中科院分区：
文献类型：
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作者：
Minghao Yi;Liang Wang;Qingquan Liu;Congmeng Hao;Zhenyang Wang;Peng Chu
虽然瓦斯抽放技术有了很大发展，但瓦斯浓度和利用率仍然很低，导致煤矿低浓度瓦斯排放量很大。为研究抽放压力对瓦斯抽放的影响，建立了基于双重介质的瓦斯运移与煤体变形耦合数学模型。模拟结果表明，初始产气量主要由裂缝渗流贡献，随后主导因素迅速转变为扩散，在大部分抽采时间内，扩散提供了相对稳定的产气量。此外，随着吸入压力的增加，气体产量的增加是微小的，而气体浓度明显降低，因为空气泄漏。为此，提出了基于浓度的抽采压力调节方法，通过调节顺层钻孔抽采压力，延长瓦斯有效抽采时间，提高瓦斯利用率。在不同抽放压力条件下进行了瓦斯抽放过程约束的现场试验，试验结果验证了该方法的有效性和适用性。研究表明，基于浓度的抽放压力调节方法是一种很有前途的实现煤矿井下安全、经济、高效抽放瓦斯的技术。
Although gas drainage technology has greatly developed, gas concentration and utilization rates are still very low, resulting in substantial quantities of low concentration gas emissions in coal mine. To study the roles of suction pressure on gas drainage, a mathematical model is developed in this study for coupled gas migration and coal deformation based on a dual-porosity medium. The simulation results reveal the initial gas production is mainly contributed by the seepage in the fracture, and then the dominating factor rapidly transitions to diffusion which provides relatively stable gas production in most drainage time. In addition, the increase in gas production is tiny while the gas concentration clearly decreases because of air leakage as the suction pressure increases. Therefore, a concentration-based suction pressure regulating method is proposed to extend the time period of effective gas drainage and increase the gas utilization rate through adjusting the suction pressure of the bedding borehole. Field tests were performed to constrain the gas drainage process under different suction pressures, and the results gained verify the effectiveness and applicability of this method. This study proves that the concentration-based suction pressure regulating method may be a promising technology to realize safe, economical and efficient underground gas drainage in coal mines in the future.