AcademicArticleSCO_85057112828

abstract

• © 2018 Institution of Chemical Engineers Over the last decade, electrochemical processes involving solid¿liquid hydrodynamic systems have been proposed for their tentative implementation in applications like water activated sludge electrooxidation as a pre-treatment for anaerobic digestion to produce biogas, mostly methane. However, electrooxidation needs to be optimized in terms of operating conditions, including improving operational flow. This work therefore, focuses on two-phase fluid dynamics and mass transport modeling of a Diaclean® cell, to establish a technical understanding of the electrochemical reactor behavior under two-phase hydrodynamics and improve operational conditions when solid¿liquid systems are involved. Modelling was performed for two scenarios: (a) a single-phase flow to evaluate a solution without any solid particles using Navier¿Stokes equations, and (b) a two-phase flow to analyze sludge using a Eulerian mixture model approach. These analyses of the proposed scenarios were validated with a simultaneous experimental study consisting of hydrodynamic studies (using mean residence time distributions tests) and mass transport characterization (by limiting electrochemical current techniques). The theoretical analysis presented here fits the experimental data obtained from residence time distribution and mass transport analysis at low Reynolds numbers quite well, but presents slight discrepancies at intermediate Re, in one and two-phase systems. This suggests refinement of the analyses is needed to consider some complex effects.