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

摘要

Mathematical models for solid cylinder and hollow cylinder pellets, where intraparticle convection was considered, have been established and solutions in the Laplace domain have been obtained. Consequent-ly, the equivalence between the hollow cylinder and the slab characteristic dimensions was presented for the first-order-reaction/diffusion/convection problem. A modified chromatographic method has been developed to measure the intraparticle diffusivity in solid cylinder pellets. The axial dispersion of the column packed with the hollow cylinder pellets was measured and a correlation for the Peclet number versus Reynolds number has been obtained. Intraparticle convection has been measured with large pore sphere pellets which present a "foam structure" by using the conventional chromatographic method. Intraparticle Peclet numbers and the permeability of this pellet were determined.