LONGITUDINAL DISPERSION IN PACKED BEDS OF POROUS ADSORBING SOLIDS

The dispersion models developed by Turner and Aris for fluids flowing in packed beds of porous solids is here extended to packed beds of porous adsorbing solids. For the nonadsorbing systems it was found that molecular diffusion, convective flow in the bed channels, and holdup in pores are additive contributions to the overall dispersion coefficient. In adsorbing systems, however, it is here shown that pore holdup and adsorption are not simply additive contributions, but are combined in a complex fashion. The general expression for the adsorption coefficient, Eq. (33), is shown to reduce to the simpler equations for porous nonadsorptive systems and for nonporous adsorptive systems (chromatographic equations, ion exchange equations). © 1968.