Mass transfer at a rotating tubular packed bed of woven screens in relation to electrochemical and catalytic reactor design

The mass transfer behavior of a rotating tubular packed bed of woven screens was studied using an electrochemical technique which involved measuring the limiting current of the cathodic reduction of potassium ferricyanide in a large excess of supporting electrolyte. Variables studied were bed rotation speed, bed thickness and mesh number of the woven screen. The mass transfer coefficient was found to increase with increasing bed rotation speed and mesh number but decreases with increasing bed thickness. The data for rotating screen bed were correlated by the dimensionless equation:Sh=4.85Sc0.33Re0.32dhd-0.25 The mass transfer coefficient at single rotating screen cylinder was found to be higher than that of rotating packed bed of screens. Both rotating single and packed bed of screens gave higher volumetric mass transfer coefficient than smooth rotating cylinder. Implication of the present results for the design and operation of electrochemical and catalytic reactors suitable for conducting liquid-solid diffusion controlled reactions such as photocatalytic reactions and immobilized enzyme catalyzed biochemical reactions was highlighted.