Simulation on Diffusion Processes of Multicomponent Gas Mixture in Typical Porous Media

The diffusion processes of gas mixture in typical porous media were simulated by the Maxwell-Stefan model to study the effect of pore radius on the diffusion process and the interaction between each species of multicomponent during diffusion in porous media.The model and the numerical method adopted here were verified by the experimental data in literature.Then the effect of pore radius was examined on the diffusion process of CH4/Ar mixture and the interaction between CH4/Ar/H2 during diffusion in porous media.The results show that the diffusion of CH4/Ar will rise with an increase in the pore radius when it is smaller than 0.5 μm while the diffusion process is independent on the pore radius when it is larger than 0.5 μm.Moreover,the adverse diffusion may occur when the dragging effect is stronger than the concentration gradient effect.In addition,species with small molecules diffuse faster than those with big molecules.These results imply that the Maxwell-Stefan model can describe the diffusion process of multicomponent gas mixture efficiently.