Application of metallic foams in electrochemical reactors of filter-press type Part I: Flow characterization

The aim of the present paper is to investigate the application of nickel foam electrodes in classical filter-press type electrochemical cells. For this purpose the ElectroSynCell®, commercialized by Electrocell AB, has been used. The interest of using metallic foams linked to a classical plane plate is to improve the performance of the electrochemical cell by increasing the electrode surface area. Moreover, for some industrial applications it is possible to use the cell without a membrane. In the proposed configuration, the working electrodes consist of metallic foam linked to a plane plate and the auxiliary electrode is simply a plane plate. The imbalance between the surface areas of working and auxiliary electrodes allows operation with a single hydraulic circuit. This paper, focuses on the study of residence time distribution and pressure drop in order to compare the flow behaviour with that in a classical configuration. A model for the reactive zone of the cell is also given.Notation D_ax axial dispersion coefficient (m2 s^–1) - ER root mean square error - F(s) transfer function in Laplace domain - I number of continuous stirred tank reactors in the first cascade (model of the two cascades) - J number of continuous stirred tank reactors in the second cascade (model of the two cascades) - L length of the path in the reactor (m) - P pressure drop (Pa) - Pe_r Peclet number of reactor - Q_v volumic flow rate (m³ s^–1) - _s mean residence time (s) - u interstitial velocity (m s^–1) - U_o mean superficial velocity (m s^–1) - X(t) experimental signal at the inlet of the reactor - Y(t) experimental signal at the outlet of the reactor - Y_ca1(t) calculated signal at the outlet of the reactorGreek letters porosity of the duct in the reactor - standard deviation - ₁ mean residence time in the first cascade (s) - ₂ mean residence time in the second cascade (s)