Method for obtaining the Knudsen diffusion coefficient

Recently, we developed a method for obtaining the Knudsen diffusion coefficient from the results of tracer experiments with a binary gas system and a porous medium in a column. The developed method employs dusty gas model (DGM) equations that consider molecular diffusion, nonequimolar fluxes, and Knudsen diffusion. The equations derived from the DGM equations for the calculation of the Knudsen diffusion coefficient can also be used to obtain the molecular diffusion coefficient and the ratio of the Knudsen diffusion coefficients of the two chemicals composing the binary gas system. We performed an inversion simulation to fit the advection–diffusion equation to the distribution of molar fractions determined by mathematically solving the advection–diffusion equation. The results confirmed that our method of obtaining the Knudsen diffusion coefficient from tracer experiment results yielded accurate values.