Characteristics of Seepage and Diffusion in Gas Drainage and Its Application for Enhancing the gas utilization rate

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.

     

原子力显微镜法研究方解石(104)面的生长及溶解

研究生物矿化过程及生物矿物的形成机制具有重要的科学意义,这方面的研究不仅有助于我们认识自然,而且还可以指导体外仿生合成具有分级结构的功能性复合材料.原子力显微镜(atomic force microscope,AFM)是微米、纳米尺度上实时观测矿物成核或生长的强有力工具.本文综述了原子力显微镜法研究方解石(104)面生...