Flow visualization and modelling of a ®lter-press type electrochemical reactor

A study of ̄ow visualization and residence time distribution is provided in order to model the ̄ow between two electrodes in a commercial ®lter-press reactor, the ElectroSynCell from Electrocell AB. Flow visualization indicates that both axial and lateral dispersion phenomena occur and a global plug ̄ow behaviour is observed. The ̄ow distribution is asymmetric due to the design of the inlet system in the active zone. The ̄ow throughout the cell is described by a dispersed plug ̄ow model for which the mean residence time and the PeÂclet number are determined. The reaction area and the inlet system are separately analysed by locating conductimetric probes inside the electrochemical cell. The reaction area is also well described by a dispersed plug ̄ow model, and characterized by high dispersion. The inlet system is, respectively, described by a dispersed plug ̄ow model and by a cascade of continuous stirred tank reactors. The high number of reactors in the cascade denotes a quasi plug ̄ow behaviour. The results are con®rmed by two cascades of continuously stirred tank reactors in series. The dispersion coecients obtained throughout the reaction area of the cell are not constant. This shows that the ̄ow is not well established at the entrance of the reaction zone and depends on the entrance conditions.