Societe Generale De Constructions Electriques Et Mecaniques 'alsthom Et

Alsthom-atlantique

Societe Generale De Constructions Electriques Et Meccaniques 'alsthom Et

Bernard Verger

Nicole Chillier-Duchatel

Philippe Demange

The invention concerns an electrolyzer power supply, especially for use in the industrial production of hydrogen. It is constituted by four sub-assemblies placed side-by-side in a filter-press type structure. These sub-assemblies each comprise electrodes coupled two by two, electrolytic compartments being defined between two groups of electrodes. One group of these electrodes, preferably half of them being made of a metal that has a rectifying effect on AC current, and preferably being aluminum, aluminum-zinc alloys, niobium or tantalum. The counter-electrodes are adapted to evolve oxygen. They are preferably iron, nickel or carbon. A generator providing an alternating current is connected between the end electrodes and between the second and third sub-assemblies. DC is taken from between the first and second and from between the third and fourth sub-assemblies.

Electrolyzer power supply

An electrolyzer for an alkaline aqueous solution and having an anode and a cathode wherein at least the cathode is made of a ternary alloy of nickel-beryllium-titanium, the proportions of beryllium and titanium being respectively 1 to 3% and 0.1 to 1% by weight. The electrolyzer is preferably used at temperatures above 110.degree. C. and at high current densities.

Process and apparatus for the electrolytic production of hydrogen

Electrochemical device for producing very pure oxygen. The device contains at least one electrochemical cell comprising an anode compartment and a cathode compartment separated by a semi-permeable membrane. The apparatus also includes an oxidation reactor chamber wherein air oxidizes the reduced form of a compound to form a peroxide capable of spontaneously decomposing into water and into the oxidized form of said compound. A portion of said decomposed peroxide is fed to the anode compartment and another portion to the cathode compartment. Oxygen is formed at the anode by electrolysis of water. The cathode reduces the oxidized form of said compound. Oxygen is removed from the anode compartment products. The remaining products of the anode compartment and the cathode compartment are returned to the oxidation reactor chamber. In another embodiment, a decomposition chamber for decomposing the peroxide is inserted between the oxidation reactor chamber and the electrochemical cell in the feed portion of the circuit.

Electrochemical oxygen production device

The invention relates to a method and an electrochemical device capable of producing very pure oxygen. Air is made to react with a reduced form of anthraquinone 2-7 sodium disulphonate in order to obtain a peroxide of this compound which decomposes to an oxidized form and to hydrogen peroxide or water depending on the pH value of the medium, said hydrogen peroxide being decomposed to water, and the water being electrochemically oxidized thus releasing the oxygen, while said oxidized form is electrochemically reduced. The invention is used for the production of very pure oxygen suitable for purifying used water.

Electrochemical oxygen production method

Apparatus for producing high purity oxygen comprising an oxidizing reactor coupled to at least one compartment of an electrochemical cell. Air is used to oxidize a reduced form of a special compound to form a peroxide which spontaneously decomposes to a mixture of the oxidized form of said compound and hydrogen peroxide. This mixture is positoned in the anode compartment of said cell and oxidized to cause the hydrogen peroxide to give off oxygen which is removed and recovered. The oxidized form of said compound is transferred to the cathode compartment wherein it is reduced and then recycled to the oxidizing reactor. The apparatus also provides a filter press-type cell containing a plurality of side-by-side compartmented electrochemical cells formed by alternating bipolar electrodes separated by porous membranes. Means are provided for coupling an oxidizing reactor to the anode compartments; for transferring material from respective anode compartments to respective cathode compartments; for removing product oxygen; and for recycling material from cathode compartments to the oxidizing reactor.

Electrochemical method and device for producing oxygen

The invention provides an electric cell having an anode compartment, a cathode compartment, and a membrane separating said compartments. The cell also has a peroxidation vessel in which sodium anthraquinone-2,7-disulfonate is peroxidized. The peroxide then decomposes to form a mixture of hydrogen peroxide and the anthraquinone oxide. This mixture is fed to the cathode compartment. When the electric cell is operated as a fuel cell, the anthraquinone oxide from the cathode compartment is conveyed to a reduction vessel in which it is reduced by contact with fuel. All or a portion of the reduced anthraquinone is then contacted with oxygen to form the anthraquinone oxide. The electric cell may also be utilized as a storage battery. The invention also includes the method of operating these electric cells.

Electric cell having peroxidized intermediate forms

Method for preparing very pure oxygen, consisting in making air in a basic medium react with the reduced form of a compound so as to form a peroxide which is capable of decomposing spontaneously into hydrogen peroxide and into the oxidized form of the said compound, and electrochemically oxidizing said hydrogen peroxide to evolve oxygen, and reducing the said oxidized form to regenerate the reduced form of the said compound. The invention is implemented in the chemical industry.

Electrochemical method for producing oxygen

The invention concerns the regulation of an electrochemical system of the Redox type. It consists in immersing three electrodes in a stream to or from a cell in the said Redox system. Two of the electrodes, referred to as measuring electrodes, are connected by two resistors defining a junction point therebetween. A direct current is applied across these electrodes. The potential of the other electrode, called the reference electrode, is compared with the potential of said junction point. The ratio between the resistors is determined so that the potentials of the said junction point and of the said reference electrode is equal, this being so for a determined power supplied by the said electrochemical system. Variation of the potential are used to regulate the flow of fuel and/or of oxidizing agent to the said electrochemical system. The invention is more particularly implemented in fuel cells using the Redox system containing anthraquinone 2-7 sodium disulphonate. The invention also includes the cells, preferably fuel cells, embodying the aforesaid apparatus.

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Chevreuse, France

Bernard Verger