Knudsen diffusion of various gases through a barium sulphate packed bed

Abstract

The diffusion coefficients, D k, of helium, krypton, carbon dioxide and air through a packed bed of barium sulphate calculated from the Knudsen diffusion flow equation were found to be a cumulative parameter obtained from the contribution of the diffusion coefficient through the voids of the packed bed, D v , and the diffusion coefficient through the pores, D p , within barium sulphate. The surface area of compacted and uncompacted material obtained from low temperature gas adsorption and the Brunauer, Emmett and Teller equation (BET), together with the void sizes and pore sizes in compacted material obtained by Barrett, Joyner and Halenda (B.J.H.) isotherm analysis, when compared with the surface area values obtained by Knudsen diffusion and permeametry, indicated that the coefficients D v and D p evaluate the void and pore areas in compacted barium sulphate, respectively.