Electrochemical Engineering Modelling of the Electrodes Kinetic Properties During Two-Phase Sustainable Electrolysis

Abstract

Abstract During two-phase electrolysis for aluminium, hydrogen or fluorine industrial production, there are bubbles which are created at electrodes which imply a quite important electrical properties and electrochemical processes disturbance. Bubbles are motion sources for the electrolysis cell flow, and then hydrodynamic properties are strongly coupled with species transport and electrical performances. Bubbles presence modifies these global and local properties: the electrolysis cell and the current density distribution are modified. This disturbance can lead to the modification of the local current density and to anode effects for example. There is few works concerning the local modelling of electrochemical processes during a two-phase electrolysis process due to the difficulty of measurements in such electrolytes. Produced bubbles involve a great hydrodynamic acceleration at the electrode interface which leads to great chemical composition modification and, sometimes, also the mechanical the electrode consumption due to both erosion and flow accelerated corrosion. Nevertheless, effects like the anode effect, particularly expensive on the point of the process efficiency, should need a better understanding. The goal of this proposition is to present the electrochemical engineering modelling of two-phase electrolysis properties at electrode vicinity. This work is due to the necessity of a better knowledge of the actual interface condition during electrolysis, for example to have a better process optimisation or electrode consumption prevention. The numerical simulation is performed from the single bubble scale to the macroscopic electrochemical cell. The present work shows both scales theoretical modelling and also performances changes during the two-phase electrolysis processes.