Effect of External Recycle On the Performance of Dialysis in Cross-Flow Parallel-Plate Membrane Modules

The effect of external recycle on the performance of dialysis in cross-flow rectangular membrane modules with feed-stream recycle was investigated theoretically. It was reported that from secondary effects or for large aspect ratio of the flat-plate module, most of the solute is transferred through the exchanger in the cross-flow arrangement

The analysis of mass transfer in parallel-plate devices with and without recycle is analogous to heat transfer in parallel-plate heat exchangers. In contrast of a device without recycle, improvement in mass transfer is achievable if cross-flow parallel-plate dialysis is operated in a device of same size with recycle which provides the increase of fluid velocity, resulting in reduction of mass-transfer resistance.