Optimization of a rotating cylinder electrode electrochemical reactor for metal recovery: An innovative approach and method combining CFD and response surface methodology

Abstract

The optimization of electrochemical reactors for metal recovery using hydrodynamic and mass transfer models with CFD is addressed. The performance of a rotating cylinder electrode (RCE) electrochemical reactor is considered. The optimization procedure has two stages.The first comprises developing a validated 3D model of metal electrodeposition at different hydrodynamic regimes. The hydrodynamics are described by the Reynolds-averaged Navier‒Stokes (RANS) equations using the standard k-ε turbulence models. The diffusion-convection equation with turbulent mixing and concentration wall function was used for the transport of electroactive species. The model was validated with experimental data obtained in a batch reactor with two different diameters of the RCE. Additionally, the model was validated in the continuous mode of operation as a part of the proposed methodology for one case of the hydrodynamic conditions for each reactor geometry.The second stage presents a methodology for optimizing the operation of an RCE reactor using the abovementioned validated models. The optimization process was carried out using response surface methodology (RSM), where three objective functions were analyzed: the fractional conversion of the reactant, the specific energy consumption, and the current efficiency. The effectiveness of the proposed method was proven by the copper ion recovery in a continuous RCE reactor under optimized conditions.