Mass transfer behaviour of a flow-by fixed bed electrochemical reactor composed of a vertical stack of screens under single and upward two phase flow

Rates of mass transfer were studied at a vertical array of closely packed s creens under single and two phase (gas-liquid) flow by measuring the limiti ng current for the cathodic reduction of ferricyanide ions. Variables studi ed were screen characteristics (mesh number and wire diameter), physical pr operties of the solution, solution flow rate, gas flow rate and the effect of surface active agents. The single phase data were correlated by the equa tion: J = 0.52 Re-L(-0.55) while the two phase data were correlated by the equations: Sh=0.87 Sc-0.33 Re-L(0.35) Re-g(0.12) for the conditions 10 < Re < 125 and 1.4 < Re-g < 77; and Sh=0.62 (ScReLReg0.25)-Re-0.33-Re-0.11 for the conditions 1.1 < Re-L < 22 and 1.4 < Re-g < 77. The presence of sur factant was found to reduce the rate of mass transfer in both single phase and two phase flow, the percentage reduction being higher in the case of si ngle phase flow.