煤岩吸附二氧化碳气体的CT实验研究

利用工业CT技术及应变测量研究不同气压下煤岩的二氧化碳气体吸附性质。研究发现：煤样的应变随吸附时间和气体压力的增加而增加,且在不同方向是不同的,吸附气体导致煤样孔隙率增加;煤样CT图像的灰度均值和灰度标准差随吸附时间和气体压力的增长都表现出增加的趋势。结果表明：吸附二氧化碳导致煤样总体发生膨胀变形,这为吸附提供更多的孔隙表面积而使吸附气体量增加,含气煤样的密度也因此而增大;气体吸附导致的煤样密度均值增加的效应大于体积膨胀导致的煤样密度均值减小的效应;吸附使煤样内部物质分布不均匀程度增加。

Experimental Study on Coal Associated with Carbon Dioxide Sorption by CT

The sorption properties of coal associated with carbon dioxide under different gas pressures were studied by X-ray CT technology and strain measurement. It is found that coal strain increases as time goes and gas pressure increases, with different values along different directions, and gas sorption leads to increase in coal porosity; Both the average value and standard deviation of gray of coal CT image manifest an increasing tendency as time goes and gas pressure increases. The results show that coal swelling deformation occurs after it adsorbs CO2, which provides more surface area for adsorbing more gas and induces increament in density of coal-gas mixture; the effect of average density increase caused by matrix adsorbing gas is larger than the effect of average density decrease caused by matrix volume expansion; and gas sorption results in the aggravation of heterogeneity of substance distribution inside the coal.