煤吸附瓦斯细观特性研究

为研究甲烷吸附孔隙压力对煤膨胀变形的影响，实验应用μCT225kVFCB型高精度显微CT实验系统，对直径为5 mm的细观煤样进行了不同孔隙压力下的吸附瓦斯扫描实验，并通过对其孔隙率与膨胀变形量的观测与分析得到了煤吸附瓦斯细观特性。研究发现：在细观实验中煤样吸附瓦斯会导致煤体孔隙率下降，并发生体积膨胀变形；体积膨胀变形规律符合朗格缪尔方程，且煤样不同位置的孔隙率与体积变化均具有非均匀性。研究结果表明：在吸附瓦斯过程中，煤体骨架体积膨胀会导致煤体孔隙体积减小与外观体积膨胀，且煤体骨架膨胀变形时更倾向于通过挤压煤体原始孔隙来获得膨胀空间。

Study on mesoscopic characteristics of methane adsorption by coal

To investigate the effects of pore pressure of methane adsorption on porosity and swelling deformation of coal，a micro-CT system named μCT225kVFCB was adopted and the coal sample was molded to cylinder shape with a diameter of 5 mm.The samples were scanned for 360 degree during methane adsorption to observe the mesoscopic characteristics.It concludes that the coal porosity decreases and the volume swelling deformation are caused by methane adsorption，and the volumetric swelling deformation obeys the Langmuir Equation.The changes of the volume swelling deformation and porosity are non-homogeneity in meso-scale coal sample，and the porosity in adsorption state is effectively estimated by the determination of coal bulk volume swelling deformation.In the process of gas adsorption，the decrease of pore volume and the expansion of bulk volume are resulted from coal skeleton volume swelling.Both of them have effects on the porosity of coal，and it inclines to squeeze the original porosity of coal to obtain spatial expansion.