G.H. Sedahmed

Mass transfer characteristics of gas-sparged fixed-bed electrodes composed of stacks of vertical screens

AbstractMass transfer rates at a gas-sparged fixed-bed electrode made of stacks of vertical screens were studied by measuring the limiting current for the cathodic reduction of potassium ferricyanide. Variables studied were air flow rate, physical properties of the solution and bed thickness. The mass transfer coefficient was found to increase with increasing air flow rate up to a certain point and then remain almost constant with further increase in air flow rate. Increasing bed thickness was found to decrease the mass transfer coefficient. Mass transfer data were correlated by the equation

Mass transfer in smooth and rough annular ducts under developing flow conditions

J = 0.2(ReFr)^{ - 0.28} ({L \mathord{\left/ {\vphantom {L d}} \right. \kern-\nulldelimiterspace} d})^{ - 0.28}

The role of mass transfer in the electrolytic reduction of hexavalent chromium at gas evolving rotating cylinder electrodes

For a single vertical screen electrode the data were correlated by the equation

Mass transfer behaviour of a flow-by fixed bed electrochemical reactor under different hydrodynamic conditions

J = 0.187(ReFr)^{ - 0.26}

Effect of drag reducing polymers on the rate of mass transfer controlled corrosion in pipelines under developing turbulent flow

Rates of mass transfer were studied at a vertical array of closely packed screens under single and two phase (gas–liquid) flow by measuring the limiting current for the cathodic reduction of ferricyanide ions. Variables studied were screen characteristics (mesh number and wire diameter), physical properties of the solution, solution flow rate, gas flow rate and the effect of surface active agents. The single phase data were correlated by the equation:J = 0.52 ReL-0.55while the two phase data were correlated by the equations:Sh=0.87 Sc0.33 ReL0.35 Reg0.12for the conditions 10 < Re < 125 and 1.4 < Reg < 77; andSh=0.62 Sc0.33ReL0.11Reg0.25for the conditions 1.1 < ReL < 22 and 1.4 < Reg < 77. The presence of surfactant 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 single phase flow.