ODC Process

The oxgen depolarized cathode for HCl electrolysis

ODC Process


The anode chamber is fed with 14% (wt.) hydrochloric acid solution. Anodic oxidation takes place and chlorine is formed while hydrochloric acid is consumed. At the outlet of the anode chamber the depleted hydrochloric acid is recovered together with chlorine in the electrolyzer header. The generated chlorine is separated from the depleted aqueous hydrochloric acid solution and collected in the chlorine header. The hydrochloric acid outlet solution is then routed to the anolyte tank. A certain portion of water as well as H+ and Cl- ions are transferred through the membrane to the cathode compartment.

The cathode chamber is fed with oxygen. At the ODC the oxygen is cathodically reduced and reacts with H+ ions coming from the anode chamber, and water is subsequently formed.

The electrolyzer is operated with an overpressure of 200 mbarg on the anode side to ensure optimum contact between the membrane and the ODC. The pressure in the anode and cathode compartments is automatically controlled. In the event of overpressure in the anode chamber, wet chlorine gas is vented to a waste gas system. In addition, automatic cathode pressure control takes place and oxygen gas can be fed to a waste gas system in case of overpressure.

Anolyte circulation

Catholyte system


Product treatment