EFFECT OF DRAG-REDUCING POLYMERS ON THE RATE OF LIQUID-SOLID MASS-TRANSFER IN FIXED-BEDS OF SPHERES UNDER FORCED-CONVECTION CONDITIONS

The effect of drag-reducing polymers on the rate of liquid - solid mas s transfer in a packed bed reactor under forced convection conditions was studied by measuring the rate of diffusion-controlled dissolution of copper spheres in acidified chromate solutions. The variables inves tigated were superficial liquid velocity, sphere diameter, bed height, and polymer concentration. The mass transfer coefficient was found to increase with increasing superficial liquid velocity. Increasing both sphere diameter and bed height were found to decrease the mass transf er coefficient. Polymer addition was found to decrease the rate of mas s transfer by an amount ranging from 29.2 tn 56.9% depending on superf icial liquid velocity and polymer concentration. Mass transfer data we re correlated in absence and in the presence of drag-reducing polymer, using the following equations, respectively: J(d) = 3.71Re(-0.54) and , J(d) = 2.5 Re-0.61 where J(d) is mass transfer J-factor and Re is th e Reynolds number.