煤瓦斯多场耦合显微观测试验装置的研制与应用

Development and application of microscopic observation device for multifield coupling of coal containing gas

为揭示在温度、地应力和瓦斯压力等多场作用下煤与瓦斯(methane)相互作用对煤矿瓦斯抽采、CO2注气强化瓦斯开采及CO2在深部不可采煤层的封存具有的重要意义,更精确地从微观角度观测在多物理场耦合条件下煤瓦斯相互作用的动态过程,研制了一种在多场耦合条件下带显微观测装置的煤瓦斯试验装置。该装置由密封容器与施力夹持机构、气压系统、温度场系统、显微观测系统4部分组成,能够通过显微观测装置结合图像处理技术,直接观测多场条件下煤与不同气体的相互作用所引起的细微变化。利用该装置进行了无应力加载、相同温度、相同气压下的瓦斯、CO2的吸附膨胀试验。研究发现,(1)试件在两种气体的变形大致经历了快速增长、缓慢增长直至平衡3个阶段,类似于吸附等温曲线;(2)试件在CO2气体中达到吸附饱和的时间比试件在瓦斯气体中达到吸附饱和的时间要短;(3)试件在瓦斯气体中的最大线性应变约为0.15%,相同条件下试件在CO2气体中的最大线应变约为0.5%,相同条件下试件在CO2气体中达到吸附饱和时的最大应变比试件在瓦斯气体中达到吸附饱和时的最大应变大3倍左右。研制的装置具有结构简单、直观、精度高的特点。

Under the multifield coupling of temperature, crustal stress and gas pressure, a coal-gas experimental device with microscopic observation has been developed to reveal the significance of the coal-gas reaction for the extraction of coal-mine gas. ECBM and the sealing of carbon dioxide in deeper coal seam, and to observe more accurately the dynamic process of coal-gas interaction under multifield coupling from a micro perspective. The microscopic-observing experimental device consists of sealed container and clamping device, pressure system, temperature-field system and microscopic-observing system. Combining with image processing techniques, the device is able to directly observe the slight changes caused by the interaction between coal and different kinds of gases under multifield circumstances. After performing adsorption-swelling deformation experiment of gas and carbon dioxide under conditions of no-stress loading, the same temperature and air pressure. Results show that:(1) The sample experienced three deformation stages in the two gases about rapid growth, slow growth and balance, which is similar to the adsorption isotherm curve.(2) The sample use time to achieve saturation adsorption in CO2 condition is shorter than it in methane.(3) The sample's maximum longitudinal stain in CO2 condition is about 0.5%, which is the three times of the value in methane at the same conditions(0.15%). It indicates that the device has features of simple structure, high visibility and accuracy.