Design of Rapid Fixed‐Bed Adsorption Tests for Nonconstant Diffusivities

Abstract

A rapid small‐scale column test (RSSCT) that uses a smaller adsorbent particle is used to simulate a five‐month pilot plant adsorption study in several days. The RSSCT is a small‐scale physical model of a full‐scale fixed‐bed such that it gives a performance identical to the full‐scale plant when the effluent profiles are plotted as the bed volumes are fed. A mathematical model that, includes axial dispersion, intraparticle pore and surface diffusion, and liquid‐phase mass transfer resistance is used to scale down the RSSCT from the pilot plant operation without extensive isotherm and kinetic data. This study presents evidence that the surface diffusivities are not necessarily constant with adsorbent particle radius and presents general scaling equations for use under these conditions.