新疆地区中低阶煤孔隙综合分形特征分析

Analysis of pore comprehensive fractal feature of medium and low rank coal in Xinjiang region

为进一步分析中低阶煤孔隙结构的分形特征,选取新疆矿区8个典型煤样,通过低温氮吸附法和压汞法测试了煤样的孔隙参数,采用氮吸附法和压汞法对煤样全孔径段孔隙结构分析的联孔位置,发现对于低阶煤为50~60nm,中阶煤为85~90nm,均位于过渡孔段。为准确分析全孔径段孔隙分形特征,采用不同的模型对煤样的分形维数进行计算。研究结果表明:试验煤样中低阶煤,孔隙均发育良好;在孔径小于联孔范围内,采用FHH模型对氮吸附试验数据进行计算,得到煤样的分形维数D1在2.58~2.89之间,在孔径大于联孔范围内,采用Menger海绵模型对压汞试验数据进行计算,得到煤样的分形维数D2在2.72~3.23之间;中低阶煤在孔隙体积占比上存在一定差异,低阶煤在孔径小于联孔范围内占比超过60%,中阶煤在孔径大于联孔范围内占比超过50%。

In order to further analyze the fractal characteristics of pore structure of medium and low rank coal,eight typical coal samples in Xinjiang mining area were selected.The tests of nitrogen adsorption method and mercury intrusion method show that the pore connection position of low rank coal is 50~60 nm,the middle rank coal is 85~90 nm,and all are located in the transition pore section.In order to accurately analyze the pore fractal features of the full-aperture section,the fractal dimension of the coal samples was calculated using different models.The results show that the fractal dimension D1 is 2.58~2.89 when the pore size is smaller than the pore connection range,the fractal dimension D2 is 2.72~3.23 when the pore size is larger than the pore connection range,the proportion of low-rank coal is more than 60%in the range of aperture smaller than the joint aperture,and that of medium-rank coal is more than 50%in the range of aperture larger than the joint aperture.