화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.109, 607-617, 2016
Intensification of the rate of diffusion controlled catalytic and electrochemical reactions in a new stirred tank reactor with a multi cylindrical blade impeller
The liquid-solid mass transfer behavior of 8 cylindrical blade impeller it can act as electrode or catalyst support in a new stirred tank reactor was studied in relation to catalytic and electrochemical reactor design by the electrochemical technique which involved measuring the limiting current of the cathodic reduction of K3Fe(CN)(6). Variables studied were blade length, impeller rotation speed, physical properties of the solution, effect of baffles, effect of immiscible liquids, effect of superimposed solution flow (continuous operation), effect of the distance between successive impellers in case of multi-impeller reactor and the effect of drag reducing polymers. The mass transfer data for single rotating impeller were found to fit the following equation: Sh = 0.429 Sc-0.33 Re-0.42 Superimposed solution flow and impeller separation were found to have little effect on the rate of mass transfer, baffles were found to increase the rate of mass transfer while the presence of immiscible liquid decreases the rate of mass transfer. Addition of drag reducing polymers (Polyox WSR-301) was found to reduce the rate of mass transfer at single impeller by a maximum of 15.8%. Examination of heavy metal removal from dilute solutions revealed that the rate of metal deposition agrees fairly with the prediction of the equation despite the presence of surface roughness and H-2 evolution. The advantages of this reactor in conducting diffusion controlled catalytic and electrochemical liquid-solid reactions and liquid-solid reactions involving sparingly soluble reactants that to be dispersed such as gases, solid particles and immiscible liquids were highlighted. (C) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.