MEASUREMENTS OF EFFECTIVE DIFFUSIVITY IN LARGE-PORE PERMEABLE PELLETSWITH VARIOUS GEOMETRIES USING THE CHROMATOGRAPHIC METHOD

Mathematical models for solid cylinder and hollow cylinder pellets, wh ere intraparticle convection was considered, have been established and solutions in the Laplace domain have been obtained. Consequently, the equivalence between the hollow cylinder and the slab characteristic d imensions was presented for the first-order-reaction/diffusion/convect ion problem. A modified chromatographic method has been developed to m easure the intraparticle diffusivity in solid cylinder pellets. The ax ial dispersion of the column packed with the hollow cylinder pellets w as measured and a correlation for the Peclet number versus Reynolds nu mber has been obtained. Intraparticle convection has been measured wit h large pore sphere pellets which present a ''foam structure'' by usin g the conventional chromatographic method. Intraparticle Peclet number s and the permeability of this pellet were determined.