多孔介质中三组分气体扩散的网络分析

NETWORK ANALYSIS OF TERNARY GAS DIFFUSION IN POROUS MEDIA

采用有效介质理论和平滑域近似的方法 ,对乙烯、氩气和二氧化碳在γ -Al2 O3 内的三组分扩散进行了网络分析 ,同时又用定态扩散实验加以验证 .研究结果表明 ,在确定了多孔介质孔结构参数 (平均配位数 )和孔尺寸参数 (孔径分布 )的前提下 ,通过网络分析的方法就可以获得有关多孔介质中多组分气体扩散的信息 .从而 。

Diffusion of ternary gas mixture of ethylene, argon and carbon dioxide in γ-Al2O3 was analyzed based on the network approach with the effective medium theory and smooth field approximation, and was verified by the Wicke-Kallenbach steady state diffusion experiment. The diffusion flux equation, including pore size distribution and pore structure parameter-mean coordination number, was calculated to get the diffusion properties of each substance without prior knowledge of the tortuosity of porous media from diffusion experiment. The alumina used in diffusion experiment had a larger range of pore radii from 1.0 to 1000.0 nm, which was cut into three intervals according to the three peaks on the diagram of mercury injection curve. The pore size and pore structure parameter could be obtained by sorption experiment. The diffusion experiment was carried out in an atmospheric cell, with temperature from 320-430 K. The results showed that the multi-component diffusion could be resolved with network analysis when pore structure (mean coordination number) and pore size (pore size distribution) parameters were known. After all, a useful method was established to describe the macro-properties of diffusion from the microstructure of porous media.