原生结构煤与构造煤孔隙结构与瓦斯扩散特性研究

Study on porous structure and gas diffusion characteristics of primary structure coal and tectonic coal

为了研究原生结构煤与构造煤孔隙结构与瓦斯扩散特性,采用压汞、低温液氮、二氧化碳吸附和稳压吸附试验对试验煤样进行研究。分析了原生结构煤与构造煤的孔隙结构特征,以及在颗粒条件下吸附瓦斯的时间效应,获得原生结构煤与构造煤孔隙的复杂程度与瓦斯在煤粒中运移快慢的关系。研究表明:祁南矿和大宁矿原生结构煤的微孔孔长度分别为8.087×10^(10)m/g和1.202×10^(11)m/g,而构造煤的微孔孔长度分别为6.932×10^(10)m/g和1.090×10^(11)m/g;给定试验煤样条件下,原生结构煤吸附达到平衡状态需要的时间远大于构造煤,构造煤在前3 min的平均吸附速率分别为原生结构煤的3.3和3.8倍;煤样中的微孔孔长度越小,瓦斯在煤中的扩散路径越短,运移所需时间越少,在初期吸附的瓦斯量越大。

In order to study the porous structure and the gas diffusion characteristics of the primary structure coal and the tectonic coal,a mercury intrusion,cryogenic liquid nitrogen,carbon dioxide adsorption and pressure stabilized adsorption experiment were applied to the experiment study on the experimental coal samples. The paper had an analysis on the porous structure characteristics of the primary structure coal and the tectonic coal and as well as the time effect of the adsorbed gas under the partical condition. A relationship between the pore complicated degree and the gas migration fast and slow speed in the coal partical of the primary structure coal and tectonic coal was obtained. The study showed that in Qinan Mine and Daning Mine,the micropore length of the primary structure coal was 8.087×10^（10） m/g and 1.202×10^（11） m/g individually and the micropore length of the tectonic coal was 6.932×10^（10） m/g and 1.090×10^（11） m/g individually. Under the certain condition of the experiment coal samples,the adsorption of the primary structure coal to reach a balanced state would have a required time far longer than the tectonic coal. In the first three minutes,the average adsorption rate of the tectonic coal would be 3.3 and 3.8 times higher than the primary structure coal individually. In the coal samples,the smaller the micropore length,the shorter diffusion path of the gas in the coal would be,the shorter time required of the migration would be and the higher gas adsorption volume in the initial period would be.