Abstract: Provided is a gas diffusion electrode equipped ion exchange membrane electrolyzer including an anode, an ion exchange membrane, and a cathode chamber in which a gas diffusion electrode is disposed, wherein the ion exchange membrane and a cathode chamber inner space in which the gas diffusion electrode is disposed are separated by a liquid retaining member, the outer periphery of the liquid retaining member is held in a void formed in a gasket or a cathode chamber frame constituting the cathode chamber, or the outer periphery and the end face of the outer periphery of the liquid retaining member are sealed, or the outer periphery of the liquid retaining member is joined to and integrated with the gasket.

Abstract: In a process for chlorine-alkali electrolysis, use is made of an oxygen depletion cathode. The process is run with a high excess of oxygen. The oxygen needed for this is provided for a device of the gas separation, for example a VPSA plant or an air fractionation plant. The large quantities of oxygen produced lead to considerable costs of the process. According to the invention, the oxygen-rich atmosphere remaining after passing through the process is fed back into the device for gas separation as input gas. The device the gas separation is therefore operated with an oxygen-rich input gas and therefore produces a larger quantity of oxygen-rich gas, which in turn is fed to the oxygen depletion cathode. As a result of the circulation of the gas, the economy of the overall process is increased considerably.

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 invention relates to a structure of a cathodic finger for diaphragm electrolysis cells consisting of an external mesh and an internal reinforcing and current-distributing structure provided with protrusions suitable for maximising the contact points with the external mesh.

Abstract: The present invention pertains to electrolytic diaphragm cells, particularly for the electrolysis of brine to produce chlorine and caustic. The innovation resides generally in the discovery that electrolytic cell operation can be desirably enhanced by compressing the diaphragm between anode and cathode. This compression of the diaphragm reduces the diaphragm thickness from an original thickness, e.g., from an original thickness of a diaphragm freshly deposited on a cathode. The reduced thickness of the diaphragm provides for cell operation that is less than zero gap operation. By maintaining the diaphragm under compression and in a reduced thickness, the cell operates with a narrower interelectrode gap and consequently at a desirably reduced cell voltage.

Abstract: The invention relates to a method for shutting down an electrolysis cell with a membrane and an oxygen-reducing cathode, which comprises, after the electrical power and oxygen supplies have been disconnected, in emptying the oxygen compartment and filling it with demineralized water having a pH≦7 and in keeping this water in the oxygen compartment throughout the shutdown period.

Abstract: A bipolar type ion exchange membrane electrolytic cell comprising an anode compartment frame which comprises an anode plate and an anode back plate arranged in substantially parallel with each other with a spacing, and a conductive anode supporting member arranged between the anode plate and the anode back plate, and a cathode compartment frame which comprises a cathode plate and a cathode back plate arranged in substantially parallel with each other with a spacing, and a conductive cathode supporting member arranged between the cathode plate and the cathode back plate, so that the anode back plate and the cathode back plate are connected back to back to form a partition wall for a bipolar electrolytic cell, wherein(a) the spacing between the anode plate and the anode back plate is wider than the spacing between the cathode plate and the cathode back plate,(b) the anode supporting member and/or the cathode supporting member, is arranged in plurality, and(c) between the adjacent anode and/or cathode supporting

Abstract: The invention discloses a novel structure for an expandable anode to be used in diaphragm cells. This new structure comprises a conductor bar in the form of a copper core provided with a titanium layer having a first and a second pair of flexible expanders fixed thereto. The welding points of the second pair of expanders are positioned orthogonally with respect to the welding points of the first pair of expanders along the circumference of the conductor bar. Also the anode surfaces are connected by welding points to the pairs of expanders. The anode of the invention may be both a new anode and a conventional existing anode having only a first pair of expanders whereto the second pair of expanders is attached. With the device of the present invention the ohmic drop between the conductor bar and the anode surface is substantially decreased and further there is no risk of damaging the interface between the copper core and the titanium coating by an excessive thermal stress, due to the welding procedures.

Abstract: The invention includes an electrolytic cell for gas-developing or gas-consuming electrolytic reactions and processes, and an electrolysis process therefor. According to the invention, the capillary slit electrode has conduits enabling the separate flow of reaction gas and electrolyte/permeate in the electrode. The electrode is preferably hydrophilic in a narrow internal region for mounting on a separator, while elsewhere it is hydrophobic. Thus electrolyte/permeate penetrates only into the region of the capillary slit electrode near the separator, while the region away from the separator remains free of electrolyte/permeate, so facilitating the unimpeded flow of the reaction gas. The invention is applicable especially in electrolytic cells for chlor-alkali or hydrogen electrolysis, and in the construction of cells for the generation of power.

Abstract: An electrode comprising a first plate (4) having an active electrode surface and a second plate (14) facing and spaced from the first plate, and at least one barrier plate (13) positioned between the first and second plates and spaced from the active electrode surface of the first plate and from the facing surface of the second plate. An electrolytic cell comprising such an electrode and the use thereof in the electrolysis of aqueous alkali metal chlorides.