Method for producing sodium hydroxide and/or chlorine, and two-chamber type electrolytic cell for saltwater

Abstract

A method for producing sodium hydroxide and/or chlorine by electrolyzing saltwater includes supplying saltwater to an anode chamber of a unit cell in a two-chamber type electrolytic cell, humidifying oxygen-containing gas in a humidifying chamber of the unit cell, and supplying humidified oxygen-containing gas generated in the humidifying chamber to a cathode chamber of the unit cell. The humidifying chamber is adjoined to and in heat exchange relation with the anode chamber or the cathode chamber in the unit cell, or is adjoined to and in heat exchange relation with an anode chamber or a cathode chamber in another unit cell adjacent to the unit cell. The oxygen-containing gas is humidified by generating water vapor with heat from the anode chamber or the cathode chamber adjoined to the humidifying chamber.

What is claimed is: 
     
         1 . A method for producing sodium hydroxide and/or chlorine by electrolyzing saltwater, the method comprising:
 supplying saltwater to an anode chamber of a unit cell in a two-chamber type electrolytic cell;   humidifying oxygen-containing gas in a humidifying chamber of the unit cell; and   supplying humidified oxygen-containing gas generated in the humidifying chamber to a cathode chamber of the unit cell,   wherein the unit cell comprises:   the anode chamber including an anode;   the cathode chamber including a gas-diffusion cathode;   an ion exchange membrane sandwiched by the anode chamber and the cathode chamber; and   the humidifying chamber,   wherein the two-chamber type electrolytic cell comprises one or more unit cells,   wherein the humidifying chamber is adjoined to and in heat exchange relation with the anode chamber or the cathode chamber in the unit cell, or is adjoined to and in heat exchange relation with an anode chamber or a cathode chamber in another unit cell adjacent to the unit cell, and   wherein the oxygen-containing gas is humidified by generating water vapor with heat from the anode chamber or the cathode chamber adjoined to the humidifying chamber.   
     
     
         2 . The method according to  claim 1 , wherein the humidifying chamber is adjoined to the cathode chamber, and wherein the humidified oxygen-containing gas generated in the humidifying chamber is supplied from the humidifying chamber to the cathode chamber through at least one opening located at a partition between the humidifying chamber and the cathode chamber. 
     
     
         3 . The method according to  claim 2 , wherein the at least one opening located at the partition between the humidifying chamber and the cathode chamber comprises a single opening. 
     
     
         4 . The method according to  claim 2 , wherein the at least one opening located at the partition between the humidifying chamber and the cathode chamber comprises a plurality of openings. 
     
     
         5 . The method according to  claim 1 , wherein the humidified oxygen-containing gas generated in the humidifying chamber is supplied from the humidifying chamber to the cathode chamber through at least one flow path located outside the humidifying chamber and the cathode chamber. 
     
     
         6 . The method according to  claim 5 , wherein the at least one flow path located outside the humidifying chamber and the cathode chamber comprises a single flow path. 
     
     
         7 . The method according to  claim 5 , wherein the at least one flow path located outside the humidifying chamber and the cathode chamber comprises a plurality of flow paths. 
     
     
         8 . The method according to  claim 1 ,
 wherein the two-chamber type electrolytic cell comprises at least two unit cells,   wherein the at least two unit cells are connected with each other, and   wherein the at least two unit cells are arranged such that the sequence of the anode chamber, the cathode chamber, and the humidifying chamber is repeated.   
     
     
         9 . A two-chamber type electrolytic cell for saltwater comprising one or more unit cells, each unit cell comprising:
 an anode chamber;   a cathode chamber;   an ion exchange membrane sandwiched by the anode chamber and the cathode chamber; and   a humidifying chamber,   wherein the anode chamber comprises an anode, and is equipped with an inlet for saltwater as a starting material, an outlet for electrolyzed saltwater, and an outlet for chlorine,   wherein the cathode chamber comprises a gas-diffusion cathode, and is equipped with an inlet for humidified oxygen-containing gas and an outlet for electrolytic reactant,   wherein the humidified oxygen-containing gas is generated in the humidifying chamber and supplied to the cathode chamber,   wherein the humidifying chamber is adjoined to and in heat exchange relation with the anode chamber or the cathode chamber in the unit cell, or is adjoined to and in heat exchange relation with an anode chamber or a cathode chamber in another unit cell adjacent to the unit cell, and   wherein the humidifying chamber is equipped with an inlet for the oxygen-containing gas.   
     
     
         10 . The electrolytic cell according to  claim 9 ,
 wherein the two-chamber type electrolytic cell comprises at least two unit cells,   wherein the at least two unit cells are connected with each other, and   wherein the at least two unit cells are arranged such that the sequence of the anode chamber, the cathode chamber, and the humidifying chamber is repeated.