Tracer dispersion in activated carbon double porosity media

G. DRAZER; R. CHERTCOFF; L. BRUNO; M. ROSEN; J. P. HULIN

CHEMICAL ENGINEERING SCIENCE

PERGAMON-ELSEVIER SCIENCE LTD

Año: 1999 vol. 54 p. 4137 - 4144

0009-2509

A new method based on radioactive dispersion is reported which permits the accurate determination of the parameters which describe the transport and exchange mechanisms for packed beds of porous particles: characteristic exchange time between theinternal and external pores (including adsorption e!ects), mean tracer velocity, mobile fluid fraction and longitudinal hydrodynamic dispersion coefficient. The method relies upon the fitting of the Coats-Smith model to radioactive tracer transit time distributions at regularly spaced intervals along a packed column for low Peclet numbers. Relationships between the transport and exchange mechanism parameters and relatively easily measured properties of the porous particles (size, porosity, intraparticle diffusion coefficient, adsorption isotherm) and packed bed (packing density) have been determined. These relationships may be used to estimatethe hydrodynamic parameters. It is shown that the transport and exchange mechanism parameters determined at low Pe numbers using the new method can be used to accurately predict behavior of the packed bed at high Pe numbers provided transport within the porous particles is explicitly included within the model.