基于低温液氮实验的不同煤体结构煤的孔隙特征及其对瓦斯突出影响

Research on the pore properties of different coal body structure coals and the effects on gas outburst based on the low-temperature nitrogen adsorption method

采集淮南煤田3个不同矿区13-1煤层、焦作矿区中马村煤矿二1煤层不同分层的不同煤体结构煤样进行低温液氮吸附试验,分析研究了不同煤体结构构造煤的孔隙特征。由此将构造煤的低温液氮回线划分为H1、H2、H3三类,构造煤的孔隙划分为4类:两端开口的孔,一端开口的孔,墨水瓶形孔和狭缝形孔。碎裂煤中主要为一端开口的圆筒形孔和两端开口的圆筒形孔;碎粒煤和糜棱煤则主要包含狭缝形平板孔、墨水瓶形孔和一端开口的圆筒形孔。研究表明:构造煤对气体的吸附一般发生在孔径3.3 nm左右的孔隙;随煤体破坏强度增大,比表面积和孔体积的分形维数均在增大。综合孔隙特征研究结果,对糜棱煤、碎粒煤煤层分布发育地区容易引发瓦斯突出的机制进行了探讨。

Different coal body structure coals,collected from the 13-1 coalbed of Huainan＇s different coal mines and 21 coalbed of Zhongmacun Coal Mine in Jiaozuo,were tested by the low-temperature nitrogen adsorption method to analyze the coal pore properties.All the extraction isotherm obtained from this test were divided into model H1,model H2,model H3,and the pores were divided into 4 types：open pore,one open end pore,ink bottle type pore and slit type pore.The fractured coal contains mostly open pore and one open end pore,and the mylonitic coal and granulitic coal contain mostly ink bottle type pore,slit type pore and open end pore.The results show that the gas adsorption are currently in the 3.3 nm coal pores,and the fractal dimensions of coal pore volume and specific surface area increases with the increase of the coal body destructive intensity.The mechanism of gas outburst arosed easily in mylonitic coal and granulitic coal areas was discussed Base on study results of pore property.