Effect of leakage currents on the primary current distribution in bipolar electrochemical reactors

Abstract

The primary current distribution in a bipolar electrochemical reactor with outside inlet and outlet electrolyte manifolds was investigated by numerical solution of the Laplace equation and by experimental measurement in simulated cells made from conductive paper and segmented electrodes. The geometric parameters determining the distribution were the interelectrode gap, electrode length, transverse section and length of the electrolyte manifold. The effect of the number of electrodes in the bipolar stack was also analysed. Values obtained numerically have been compared with those obtained experimentally and a good agreement is observed between them. These results are useful for estimating the performance of the bipolar stack. List of symbols aGeometric parameter of the manifold (m) A Transverse section of the electrolyte manifold (m 2 ) bGeometric parameter of the manifold (m) d r Mean relative deviation (%) eInterelectrode gap (m) G Length of the electrolyte manifold (m) jCurrent density (A m -2 ) j mean Mean current density (A m -2 )

Effect of leakage currents on the secondary current distribution in bipolar electrochemical reactors

“…6. The experimental current distributions at the bipolar electrode are more uniform than at the terminal electrodes, which corroborates the tendency also observed for the primary case [1,2]. However, an important variation in the current density takes place in the first segment near the manifold, which disagrees with the theoretical model and can be attributed to a change in effective electrolyte resistance due to the gas evolved at the electrodes.…”

“…and the primary potential distribution inside the reactor was determined according to the method outlined in [2]. For a given axial position y along the electrode length, the four potential points in the solution phase nearest to each electrode surface, that is / s (h, y), / s (2h, y), / s (3h, y) and / s (4h, y), were fitted with the polynomial:…”

“…The authors have previously proposed a simplified model to predict the effect of the leakage current on the current distribution [1]. In [2] the primary current distribution obtained by the numerical solution of the Laplace equation was reported and compared with experimental results. The state of the art related to bipolar electrochemical reactors has recently been described [1,2].…”

“…In [2] the primary current distribution obtained by the numerical solution of the Laplace equation was reported and compared with experimental results. The state of the art related to bipolar electrochemical reactors has recently been described [1,2]. Some authors have analyzed particular aspects of these devices.…”

Comparison between primary and secondary current distributions in bipolar electrochemical reactors

“…However, one disadvantage of this electrical connection is the presence of leakage currents, flowing through the connecting manifolds and pipes, which can modify the current distribution in the reactor. Thus, in previous works from this laboratory [8][9][10] the primary and secondary current distributions were analyzed and the theoretical results were compared with experimental data. A satisfactory concordance between them was reported.…”