Operation of a cation exchange membrane electrolytic cell for producing chlorine including feeding an oxidizing gas having a regulated moisture content to the cathode

Claim 1

In a process to produce chlorine and an alkali metal hydroxide in an electrolytic diaphragm cell by feeding an alkali chloride brine to an anode compartment and passing alkali metal ions through the diaphragm into a cathode chamber, supplying sufficient electrical energy to an anode positioned in the anode compartment and a cathode positioned in the cathode compartment to release gaseous chlorine at the anode and form an alkali metal hydroxide in the cathode compartment and recovering the chlorine and alkali metal hydroxide, the improvement in the cell with a cation exchange diaphragm comprising substantially simultaneously contacting different surface portions of the cathode with the catholyte and with an oxidizing gas, regulatably controlling the moisture content of the oxidizing gas entering the cell so as to minimize deposition of solid materials on the cathode, circulating the catholyte within the cathode compartment and controlling the catholyte head to maintain the catholyte upper surface level at a higher level than the anolyte upper surface level to thereby improve the electrical efficiency of the cell.