Abstract: Apparatus for producing alkali hydroxide and method for operating apparatus for producing alkali hydroxide are provided. A cooling chamber through which a coolant can pass is constructed by placing a separation wall in a cathode chamber on a side opposite to an ion-exchange membrane, and a flow rate adjuster, such as manual valves, which can adjust the supply flow rate of the coolant is placed in each unit cell. The electrolytic temperature of each unit cell is regulated at an optimum operating temperature depending on the current density by adjusting the flow rate of the coolant without individually adjusting the flow rate of salt water supplied to the unit cell or the concentration of the salt water.

Abstract: Apparatus for producing alkali hydroxide and method for operating apparatus for producing alkali hydroxide are provided. A cooling chamber through which a coolant can pass is constructed by placing a separation wall in a cathode chamber on a side opposite to an ion-exchange membrane, and a flow rate adjuster, such as manual valves, which can adjust the supply flow rate of the coolant is placed in each unit cell. The electrolytic temperature of each unit cell is regulated at an optimum operating temperature depending on the current density by adjusting the flow rate of the coolant without individually adjusting the flow rate of salt water supplied to the unit cell or the concentration of the salt water.

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.

Abstract: Apparatus for producing alkali hydroxide and method for operating apparatus for producing alkali hydroxide are provided. A cooling chamber through which a coolant can pass is constructed by placing a separation wall in a cathode chamber on a side opposite to an ion-exchange membrane, and a flow rate adjuster, such as manual valves, which can adjust the supply flow rate of the coolant is placed in each unit cell. The electrolytic temperature of each unit cell is regulated at an optimum operating temperature depending on the current density by adjusting the flow rate of the coolant without individually adjusting the flow rate of salt water supplied to the unit cell or the concentration of the salt water.

Abstract: [Problems] The liquid pressure of an anode chamber in a two-chamber ion exchange membrane electrolytic cell using a gas diffusion electrode are different among one another depending on depths so that the liquid pressures are applied on an anode or an ion exchange membrane, thereby introducing damage or deformation of the elements. [Means for Solving] A cushion material 10 is accommodated between a cathode gas chamber back plate 9 and a gas diffusion electrode 7 of an ion exchange membrane electrolytic cell 1 such that a repulsive force of the cushion material at the bottom part of the cathode gas chamber is larger than that at the top part. The excessive pressure applied to an ion exchange membrane is suppressed to prevent the generation of scratches or the like by decreasing the repulsive force of the cushion material toward the top in accordance with a differential pressure between an anode chamber pressure and a cathode gas chamber pressure.

Abstract: The present invention contemplates for providing a producing method which can give highly pure caustic potash in a relatively simple process, in response to the above-described demand for increased high purity in caustic potash. A method to give highly pure caustic potash containing almost no impurities of sodium, chlorine, and heavy metals, such as iron, chromium and nickel, through crystallization, by bringing an aqueous caustic potash solution having a sodium content of 200 mg/kg or less and a chlorine content of 15 mg/kg or less when calculated in terms of a weight of potassium chloride, in which a caustic potash concentration of 48% is to be a standard, into a high temperature state.

Abstract: A method of treating a ballast water for sterilizing bacteria, microorganisms or organisms in the ballast water in a hold or ballast tank of a ship, has the steps of: sterilizing the bacteria, microorganisms or organisms by adjusting a residual chlorine concentration in the ballast water to 1 mass ppm or more and 1000 mass ppm or less with a hypochlorite, and removing the residual chlorine in the ballast water with a sulfite.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: The present invention contemplates for providing a producing method which can give highly pure caustic potash in a relatively simple process, in response to the above-described demand for increased high purity in caustic potash. A method to give highly pure caustic potash containing almost no impurities of sodium, chlorine, and heavy metals, such as iron, chromium and nickel, through crystallization, by bringing an aqueous caustic potash solution having a sodium content of 200 mg/kg or less and a chlorine content of 15 mg/kg or less when calculated in terms of a weight of potassium chloride, in which a caustic potash concentration of 48% is to be a standard, into a high temperature state.

Abstract: [Problems] The liquid pressure of an anode chamber in a two-chamber ion exchange membrane electrolytic cell using a gas diffusion electrode are different among one another depending on depths so that the liquid pressures are applied on an anode or an ion exchange membrane, thereby introducing damage or deformation of the elements. [Means for Solving] A cushion material 10 is accommodated between a cathode gas chamber back plate 9 and a gas diffusion electrode 7 of an ion exchange membrane electrolytic cell 1 such that a repulsive force of the cushion material at the bottom part of the cathode gas chamber is larger than that at the top part. The excessive pressure applied to an ion exchange membrane is suppressed to prevent the generation of scratches or the like by decreasing the repulsive force of the cushion material toward the top in accordance with a differential pressure between an anode chamber pressure and a cathode gas chamber pressure.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alkyl ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In a gas diffusion electrode assembly, and in an electrolyzer using the same, a bonding piece having on at least one surface a perfluorosulfonic acid layer, a perfluorosulfonyl fluoride layer or an alky ester of perfluorocarboxylic acid layer is positioned at its perfluoro compound layer surface with respect to the gas diffusion electrode assembly. Adjacent gas diffusion electrodes are heat fusion bonded together, or heat fusion bonding is carried out using the bonding piece in a frame form. Adjacent gas diffusion electrodes are sealed up by heat fusion bonding, using a material that is similar to the material that forms the gas diffusion electrodes.

Abstract: In order to discharge current from a gas diffusion electrode in an electrolytic unit cell including a gas chamber, the gas diffusion electrode is electrically connected to the wall surface of the gas chamber having conductivity through an electric connecting element in partial contact with the gas diffusion electrode