DETERMINATION OF MASS TRANSPORT PARAMETERS FOR FIXED-BED ADSORBERS

Abstract

An innovative technique has been developed for determination of external (“film”) and internal (“intraparticle”) mass transport parameters associated with uptake of solutes by porous solids in fixed-bed adsorbers. These parameters are required for predictive modeling of the dynamics of such systems as activated carbon columns and ion exchange beds. Current methods for evaluation of film transfer coefficients and effective intraparticle diffusivities involve correlation procedures and separate batch-reactor measurements of adsorption rates, respectively. These methods frequently introduce and compound significant errors in subsequent predictive modeling Tor full-scale process design. The present work develops a method by which, on the basis of the characteristics of breakthrough curves measured in specially designed micro-columns, more accurate and reliable simultaneous determinations of both film transfer coefficients and effective surface diffusivities can be done. Verification of the procedure is demonstrated by the agreement of predictions generated from a mathematical model, in which mass transfer coefficients determined from the micro-column technique are used, with experimental breakthrough data for larger scale adsorbers.