The kinetic and hydrodynamic behaviour of a fixed-bed electrochemical reactor was studied in terms of current efficiency (CE) and energy efficiency (EE). In the kinetic experiments the effects of fixed bed thickness (L), current density (i) and initial concentration of copper (C0) were studied. In the hydrodynamic experiments the permeability (k) of the electrode and the coefficient for inertial forces (c) were also studied as functions of the applied current density. At low current densities and bed thicknesses greater than 1.0 cm, negative CE and EE were observed as a consequence of the dissolution of the porous matrix. At high current densities low CE and EE were observed and a powdery deposit was formed on the surface of the particles. From the results of the kinetic study bed thickness and the range of current densities employed in the hydrodynamic experiments were chosen. In these experiments the electrodeposition process continued until the whole electrode had been clogged and no more electrolyte could pass through it. The relationship between pressure drop and flow rate was well described by the Forchheimer equation. It was observed that the reduction in porosity due to copper electrodeposition causes the flow rate to decrease because of the decrease in electrode permeability, but it had no influence on current efficiency.
fixed-bed; electrochemical reactor; hidrodynamic
