软硬煤孔隙结构特征及对变压解吸规律的影响

Pore Structure of Soft and Hard Coal and Its Influence on Gas Desorption Characteristics Under Variable Pressure

以河南平煤十矿、郜成矿和贵州新田矿的硬煤和软煤为研究对象,通过变压解吸实验分析煤样在变压条件下的解吸规律,并结合压汞实验,从孔隙结构层面分析硬煤和软煤变压解吸的控制机理。结果表明:变压解吸过程中,所有煤样解吸速率均由最大初始值随时间逐渐减小;不同压力值下的解吸量随压力变化上下波动,整体呈现逐渐降低趋势;当压力降至3 MPa以下时,由于在连通的中孔及大孔中解吸出的气体压力不足以持续克服毛细管压力,波动幅度急剧加大;同等压降条件下,软煤比硬煤解吸量更大;总体上软煤解吸速率更快,累计解吸量更多。

The hard coal and soft coal from No.10 Mine in Henan Pingdingshan, Gaocheng Mine and Guizhou Xintian Mine was selected to carry out mercury intrusion experiments and gas desorption experiments under the condition of changeable pressure.The pore structure characteristics and gas desorption laws are analyzed. The results show that the desorption rate of all coal samples decreases from the maximum initial value with the time during the process of changeable pressure desorption. The desorbed gas amount is up and down under different pressure, the overall trend is gradually decreasing. While the pressure is below 3 MPa, the fluctuation increases sharply because the desorbed gas pressure in the connected mesopores and macropores is not sufficient to continuously overcome the capillary pressure. The soft coal has more desorption capacity than hard coal under the same pressure drop condition. The desorption rate of soft coal is faster and the accumulated desorption amount is more.