含瓦斯煤吸附特性影响因素研究

Study on the Influencing Factors of Gas-containing Coal Adsorption Characteristics

为研究含瓦斯煤物质组成成分和孔隙结构参数对煤吸附能力的影响,采用压汞试验测试了5种煤样的孔隙结构,并研究了含瓦斯煤比表面积、平均孔径、孔隙度和分形维数等4种孔隙结构参数,分析了含瓦斯煤物质组成成分和孔隙结构参数对瓦斯吸附能力的影响。研究表明:水分、挥发分、比表面积与瓦斯极限吸附量(VL)呈二次函数关系,灰分和VL呈负相关,平均孔径和孔隙度与VL呈正相关。Langmuir压力(PL)随着灰分和挥发分的增大而增大,随平均孔径和孔隙度的增大而减小,且与比表面积呈二次函数关系。煤样在不同压力阶段具有不同分形特征,因此具有不同的分形维数D1(r<10nm)和D2(r>10nm)。D1和D2均大于2.9,分形特征明显。VL随着D1的增大而增大,随着D2的增大而减小。分形维数与PL的关系不明显。

In order to study the influence of gas-containing coal composition and pore structure parameters on coal adsorption capacity,the pore structures of five coal samples were tested by mercury intrusion test,and the specific surface area,average pore size,porosity and fractal dimension of gas-containing coal were studied.Then,the influence of gas-containing coal composition and pore structure parameters on coal adsorption capacity was analyzed.The results show that the moisture,volatile matter and specific surface area have a quadratic function relationship with the limit adsorption capacity(VL),ash has a negative correlation with VL,and average pore size and porosity are positively correlated with VL.Langmuir pressure (PL)increases with the increase of ash and volatile matter,decreases with the increase of the average pore size and porosity,and has aquadratic function relationship with the specific surface area.Coal samples have different fractal characteristics at different pressure stages,so they have different fractal dimensions D1(r<10nm)and D2(r>10nm),both D1 and D2 are greater than 2.9,and the fractal characteristics are obvious.VLincreases with the increase of D1 and decreases with the increase of D2.The relationship between fractal dimension and PLis not obvious.