不同煤级煤样的孔隙综合表征方法研究

Research on comprehensive characterization method of different rank coal porosity

煤的孔隙特征对于研究煤的吸附解吸特性、扩散性、渗透性以及瓦斯突出事故的发生机理具有非常重要的意义。为研究不同煤级煤样的孔隙综合分形特征,利用ASAP2020比表面积及孔径分布测定仪,在低温液氮的环境下,对不同变质程度的煤样进行孔隙测定,并利用FHH分形维数计算模型对实验数据进行拟合,得到各煤样不同孔径段的分形维数;同时利用各孔径段的孔隙体积比作为权值,对各个煤样不同孔径段的分形维数进行加权求和,得到各煤样的综合分形维数。将煤样的综合分形维数与其总孔隙体积进行比较分析,可知不同煤级煤样的孔隙具有明显的分形特征,其总孔隙体积越大,综合分形维数越大,孔隙表面越粗糙,孔隙分布则相对复杂。

The pore characteristics of coal for the adsorption desorption, diffusivity and permeability, and medhanism of the gas outburst accident have a very important significance. In order to study the different coal sample pore total fractal characters, using ASAP2020 specific surface area and pore size distribution analyzer in the low temperature liquid nitrogen environment the different metamorphic degree of coal samples were de- termined. And fitting the data by FHH model, take the fractal dimension of the different pore section. At the same time, by using the pore volumn ratio as weights, the fractal dimension of each coal sample sections of different diameters by weighted sum, get the total fractal dimension. Comparing with the pore volumn of coal samples, the result is that（ 1 ）the pore of the different coal sample has obvious fractal characteristics; （2）the greater the pore volumn, the higher the total fractal dimension ; （3） the pore surface is rougher and pore distri- bution is relatively complex.