Parallel Plate Electrochemical Reactor Model: Material Balance Closure and a Simplification

Abstract

A material balance closure calculation is presented to test the consistency of a previously published model of a parallel plate electrochemical reactor. New expressions are used in this procedure to calculate the average concentration of species normali and the average current density for reaction normalj from the predicted concentration and potential distributions. Also, the previously presented model equations are simplified by assuming that the axial concentration gradient for species normali can be approximated by a step change from the known feed concentration to the unknown outlet concentration. This one‐step model provides a qualitative evaluation of cell performance and adds insight into understanding of the previous model, while providing substantial savings in computer time. The models are compared using a hypothetical case of the electrowinning of copper from a chloride solution. For a small aspect ratio false(S/Lfalse) , the models show that a set of independent variables consists of the cell potential false(Enormalcellfalse) , the surface area of an electrode per unit of cell volume false(1/Sfalse) , and the residence time false(L/υnormalavgfalse) when the feed concentrations false(cnormali,normalfeedfalse) are fixed.

Simulation of a Parallel Plate Electrochemical Reactor Used to Remove Cr(VI)via Electrocoagulation Method

“…The same phenomenon can be found for OH -on the cathode electrode. Two peaks are observed in the concentration distribution of CrO 4 2-shown in Fig. 3c for Peγ less than 500.…”

“…The concentration distributions of Fe 2+ , OH -and CrO 4 2-at the exit of the PPER (ξ=1) were simulated and shown in Fig. 3 a, b and c, respectively at different Peγ values.…”

“…The migration of CrO 4 2-near the cathode and the consumption by reaction 1 near the anode result in the concentration peak formation near the cathode electrode. The other concentration peak occurs in the reaction region where the concentration of CrO 4 2-is in a low level. The migration of CrO 4 2-in this region is more important than the diffusion, which causes the formation of the concentration peak near the anode.…”

“…Cr(VI) is reduced by Fe 2+ in the solution phase. The products Cr 3+ and Fe 3+ are precipitated by OH -to form Cr(OH) 3 and Fe(OH) 3 (3,4) approximated the concentration gradient of a species respect to the reactor length by a step change in concentration between the reactor inlet and the outlet. This simplified model was called One-Step Model.…”

Simulation of Reduction of Cr(VI) by Fe(II) Produced Electrochemically in a Parallel-Plate Electrochemical Reactor

“…15 Applying the one-step approximation 12 for the concentration gradient in the axial convection term yields…”