摘要
利用氮气等温吸附脱附法和电镜扫描研究了印尼油砂干馏热解过程中半焦表面特性的变化,并利用分形维数来定量描述半焦表面形态的复杂程度。结果表明,半焦BET比表面积与孔容积随干馏终温的变化趋势相近,均呈现先增大后减小的趋势。通过FHH方程回归得到的分形维数能够较好地反映半焦内部孔隙结构的分形特性,挥发分的吸出、塑性变形、气体产物的逸出以及油蒸汽的再凝结造成的闭孔效应的多种作用的交替影响,使分形维数在不同的温度区间有不同的变化趋势。电镜扫描能够直观地观察到半焦表面的孔结构特征,利用Matlab编程分析电镜图片得到的盒子维数与氮吸附数据拟合得到的FHH分形维数变化趋势基本一致。
The nitrogen isothermal adsorption-desorption method and scanning electron microscope were conducted to investigate the variation of the semi-coke surface characteristics in the course of the Indonesian oil sand pyrolysis in this research, and the fractal dimension was used to quantitatively describe the complexity of the semi-coke surface morphology. The results showed that the trends of the char BET surface area and the pore volume towards the final retorting temperature were similar, firstly increasing and then decreasing. The fractal feature of the semi-coke particles internal porosity could be well illustrated by the fractal dimension obtained by the regression of the FHH equation. The tendency of the fractal dimension varied in different temperature ranges, due to the alternating impact of multiple effects, including the devolatilization, the plastic deformation, the escape of gas products and the recondensation of oils. The semi-coke surface pore structure characteristics can be directly observed through the SEM, and the trends of the box-counting fractal dimension by the application of Matlab programming to the SEM picture and the FHH fractal dimension were proximately consistent.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2014年第4期891-895,共5页
Chemical Industry and Engineering Progress
基金
国家自然科学基金项目(51276034)
关键词
油砂
吸附
表面
热解
分形维数
oil sands
adsorption
surface
pyrolysis
fractaldimension
