School of Resource and Safety Engineering, China University of Mining and Technology (Beijing)

为了定量表征煤粒孔隙结构特性,选取褐煤、烟煤和无烟煤3个不同煤阶煤样分别破碎成3个不同粒度的煤粒进行压汞试验,基于Menger海绵模型和热力学模型对试验数据进行处理,研究了煤粒孔隙的分形特性。研究表明:基于Menger海绵模型得到的试验曲线不符合线性关系,曲线分为2段,前段分形维数DM大于3,后段线性拟合度太低;采用热力学模型分析孔隙分形特性时,曲线呈现显著的线性关系,拟合度均在0.98以上,且分形维数DT均在2~3。表明热力学模型较Menger海绵模型更适合研究煤粒孔隙的分形特性。DT随着煤粒度的减小而减小,且煤粒度对其影响较小;DT随着煤阶的升高而减小,并从煤变质作用的角度分析了其原因。

In order to indicate the structure properties of the coal porosity quantitatively, three different coal rank samples, including lignite, bituminous coal and ant hracite, were selected to break into three different granularity, and the mercury porosimetry test was then performed. Based on the Menger sponge model and the therm odynamic model, the experimental data were processed to study the fractal characteristics of coal porosity. The results showed that the curves obtained from the Meng er sponge model did not fit the linear relationship.The curve was divided into two segments. The fractal dimension value DMof the front segment was greater than 3, an d the linear ftting degree of the back segment was too low. When the thermodynamic model was used to analyze the fractal characteristics of the pore, the curves show ed a significant linear relationship, and the ftting degree was more than 0.98. Meanwhile, the fractal dimension DTwas between 2 and 3.It was shown that the thermody namic model was more suitable for studying the fractal characteristics of the coal porosity than Menger sponge model. DTdecreased with the decrease of the coal partic le size, and the coal particle size had lttle effect on it. DTdecreased with the increase of coal rank, and the reason was analyzed from the viewpoint of the coal metamo rphism.