典型工业半焦的孔隙分形结构分析

工业半焦是一种具有复杂的微观孔隙拓扑结构的多孔物质.基于分形理论,引入分形维数对工业半焦不规则孔隙结构的粗糙、复杂程度进行了定量表征和描述.选取具有典型煤种和工艺代表性的工业半焦样品,用孔隙度分析仪对其孔隙结构特征进行了测量,并利用其测量数据进行了分形维数的分析计算.计算结果表明,工业半焦的孔隙结构符合分形特征,在样品颗粒尺寸为2.36～3.35mm的测量条件下,样品的分形维数在2.7982～2.9154之间,其可决系数在0.9157～0.9614之间;样品的分形维数与煤种和半焦热解工艺过程均有一定的关系.通过对工业半焦分形维数的计算分析,可以更加全面准确地了解其孔隙结构特征,以期为分析评价其吸附和活化潜力、制定恰当的活化工艺提供更加可靠的依据.

Fractal dimension analysis of typical semi-cokes based on mercury porosimetry

Industrial semi-cokes are typical pore-rich particles with complex microscopic pore structure. Based on fractal theory, the fractal dimension was introduced to quantitatively characterize the roughness and complexity of the irregular pore structure. Samples derived from four different coals treated with different pyrogenation processes were selected. The pore structure of semi-coke particle samples with diameters between 2.36 mm and 3.35 mm were analyzed with the Mercury Porosimeter PoreMaster-60, based on which the corresponding fractal dimensions were calculated. The results indicate that the pore structure of industrial semi-cokes agrees with fraetal characteristics. The fractal dimensions are between 2. 7982 and 2. 9154, and the determination coefficients are in the range of 0. 9157 - 0. 9614. The fractal dimensions from the available samples in this study are relevant to coal ranks and/or different pyrogenation processes. The pore structure of industrial semi-cokes can be reasonably characterized with fractal dimensions in term of evaluating adsorption or activation abilities and determining appropriate activation methods.