煤孔隙特征对瓦斯放散初速度影响研究

Study on influence of coal pore characteristics on initial velocity of gas emission

煤的瓦斯放散特性是表征煤与瓦斯突出危险性的关键指标之一,不同变质程度煤的瓦斯放散初速度ΔP差异很大。为分析其内在影响机制,采用N_(2)吸附法和CO_(2)吸附法对不同变质程度煤进行孔径分析,研究了大孔、介孔和微孔孔隙比表面积、体积和平均直径对ΔP的影响。结果表明:ΔP随Langmuir体积增大呈线性增加的趋势,而与Langmuir压力无关;随微孔比表面积增大,ΔP呈幂函数增长,ΔP与煤的大孔、介孔和微孔体积及平均孔径呈正相关;挥发分与Langmuir体积近似呈幂函数关系,与ΔP呈负指数关系;微孔比表面积大小、微孔孔隙体积、微孔平均直径是煤微观结构影响ΔP的主要参量。因此,随变质程度增高,ΔP呈增大趋势,主要是受煤内微孔发育的影响。

The gas emission characteristics of coal is one of the key indicators to characterize the coal and gas outburst risk.The initial gas emission velocityΔP of coal varies greatly with different metamorphic degrees.In order to analyze its internal influence mechanism,the N_(2) adsorption method and CO_(2) adsorption method were used to analyze the pore size of coal with different metamorphic degrees,and the effects of the specific surface area,volume and average diameter of macropore,mesopore and micropore pores onΔP were studied.The re⁃sults show thatΔP increases linearly with the increase of Langmuir volume,and has nothing to do with Langmuir pressure;ΔP increases with the power function of the specific surface area of the micropores,andΔP is positively related to the volume of macropore,mesopore and micropore and the average pore diameter.Volatile matter is approximately in a power function relationship with Langmuir volume,and is in a negative exponential relationship withΔP.The micropore specific surface area,the volume of the micropores,and the average di⁃ameter of the micropores are the main parameters affectingΔP.Therefore,ΔP tends to increase as the degree of metamorphism increases,which is mainly affected by the development of micropores in coal.