Numerical and experimental evaluation of the general performance in a modular electrochemical reactor and its feasibility for electro-chlorination purposes: Effect of the different electrode assembly configurations

• Published in: Chemical engineering research & design 2022-01, Vol.177, p.45-55
• Main Authors: López-Maldonado, J.T., Rivera, F.F., Castañeda-Zaldívar, F.
• Format: Article
• Language: English
• Subjects: Assemblies; CFD; Chemical reactors; Chlorination; Chlorine; Configurations; Current distribution; Edge effect; Electrode stack; Electrodes; Feasibility studies; Fluid dynamics; Heat transfer; Mass transfer; Mass transport; Modular units; Numerical analysis; Oxidation; Pollutants; Potential-current distribution; Pressure drop; Reactors; Velocity distribution
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2021.10.001

[Display omitted] •Computational tools allowed evaluating the behavior in the electrochemical reactor.•The cross-sectional area in the electrodes plays an important role in pressure drop.•Interspersed electrode produced non-uniform current lines affect the mass transfer. Evaluation of electrochemical reactors consisting of different electrode assemblies, stacks, or modular units, by the employing of computational techniques and its comparison with experimental data is desirable for its applications and scaling up for electrochemical processes like the mediated electro-chlorination. This work aimed to evaluate the effect of three different electrode configurations (flat, interspersed, and C-stack assemblies) on the general performance of a homemade modular reactor, based on former ElectroSyn design with an improved inlet-outlet system, through studies of hydrodynamics, electrical characteristics, and mass transfer. Additionally, a secondary potential-current distribution study was carried out to evaluate the feasibility of different electrode configurations tested for the electro-chlorination process, that can be applied mainly for environmental purposes like mediated oxidation of organic pollutants and disinfection by the production of active chlorine species. From the hydrodynamic study, velocity profiles and RTD curves obtained in all electrode configurations tested, suggest that the flat electrode configuration exposes a low fluid dispersion and resistance than the other configurations, because of the diminishing of the high-velocity zones and by its higher cross-sectional area, which was confirmed by the pressure drop measurements. On the other hand, calculation of primary and secondary current distribution suggests that the presence and modification of edge effect in the different configurations tested generate strong non-uniformities in the electrode corners and the reactor walls, which could affect the distribution of reaction rate during the mass transport evaluations. Also, the secondary potential-current distribution study indicates that the flat and C-stack configurations are the more electrical feasible configurations (since the effect of the flow field and mass transfer was not taken into account) to be applied in the electro-chlorination process.