RU2139956C1 - Plant for production of hypochlorites solutions by electrolysis - Google Patents

Abstract

FIELD: production of hypochlorite solutions by electrolysis; applicable in treatment of household and industrial sewage waters. SUBSTANCE: plant has body with supplying and discharging pipelines, gas-withdrawal pipe and electrode unit having titanium anodes with ruthenium-oxide coating and titanium cathodes with ruthenium-oxide coating in electrolysis of hard waters, that provides for removal of sediment without plant stopping by current reversing. EFFECT: higher reliability of plant in electrolysis of hard waters. 2 cl, 1 dwg

Description

 The invention relates to the field of production of hypochlorite solutions by electrolysis and can be used for the treatment of domestic and industrial wastewater.

 Known electrodialyzer, in which the removal of sediment from the cathode upon receipt of hypochlorite in the electrode chambers is produced by reverse current. (ISSN 0203-7815. Chemical industry. Series "Production and processing of plastics. Overview information. The main scientific and technical directions of the development of the problem of electrolysis (processes and devices) in the USSR and abroad. NIITEKHIM. M., 1986, S. 46 )

 The disadvantage of this device is the use of platinum titanium as electrodes, which significantly increases the cost of this device.

 Known installation type EN for sodium hypochlorite, containing a node for dissolving salt, an electrolytic cell with an exhaust ventilation umbrella, a storage tank of the finished solution, a rectifying unit for powering the electrolyzer, a control cabinet and shut-off valves. ("Manual on the design of structures for water purification and preparation". M., 1988. S. 110).

 The disadvantage of the installation is the use of carbon anodes that wear out quickly.

 The closest technical solution is the installation of the type "Stream", for disinfection of water by direct electrolysis, containing a housing with inlet and outlet pipes, a gas outlet pipe, an electrode block having titanium anodes with oxide-ruthenium coating. ("Manual on the design of facilities for treatment and water treatment". M., 1989. S. 112).

 The resistance of ruthenium oxide titanium anodes is much greater than that of carbon anodes.

 The disadvantage of this device is that during electrolysis of hard water at the cathode, a precipitate forms, which leads to an increase in voltage on the electrolyzer and a deterioration in the hydrodynamics of the process. The day of removal of the precipitate, the installation is disassembled and the cathodes are treated in hydrochloric acid.

 The technical task of this invention is to increase the reliability of the installation during the electrolysis of hard waters.

 This technical problem is achieved by the fact that in the installation for the production of hypochlorites by electrolysis, including a housing with inlet and outlet pipes, a gas outlet pipe, an electrode unit having titanium anodes with an oxide-ruthenium coating, titanium cathodes are used to remove the precipitate without stopping this unit by reversing the current. with ruthenium coating, as well as for more efficient gas removal when placing the electrode block in the main conduit in front of the clean water tank, the conduit being oh knee, consisting of a horizontal portion where the electrode assembly and installed baffle providing flooding of electrodes and a vertical portion directed directly to the clean water tank, there is an additional gas outlet connected to the bend of the knee in its lower part.

 The drawing shows a diagram of an installation for producing hypochlorite solutions by electrolysis.

 The apparatus for producing hypochlorite solutions by electrolysis includes a water conduit 1, consisting of a horizontal part 2, a vertical part 3, and a lower part of a bend of a knee 4. In a horizontal part 2 of a water conduit 1, an electrode unit 5 consisting of 75 titanium cathodes with an oxide-ruthenium coating and 75 of the same anodes, the main gas outlet 6, the partition 7. An additional gas outlet 8 is connected to the lower part of the bend of the knee 4.

 Installation works as follows.

 Water is supplied through the water conduit in the direction of the arrow (drawing), and due to the partition 7, the electrodes of the electrode unit 5 are flooded. DC voltage is applied to the electrodes and an electric current flows through the water between the electrodes, while chlorine and oxygen are generated at the anode, and hydrogen is at the cathode. In addition, acid is released at the anode, and alkali at the cathode. Alkali interacts with chlorine, forming hypochlorite, which dissolves in water and produces a disinfecting effect. At the same time, most of the alkali interacts with calcium and magnesium bicarbonates, forming a precipitate at the cathode. When the current is reversed, the cathode becomes an anode, and an acid begins to precipitate on it, which interacts with the precipitate, which is mainly calcium carbonate, and the sediment is removed from the electrode.

 The gaseous products of electrolysis - hydrogen and oxygen - are removed through the main gas outlet 6, but most of them are carried away with the flow of water into the vertical part of the waterway 3. In this part of the waterway, gases are separated from the water and removed through an additional gas outlet 8. Without this gas outlet, a gas conduit was formed gas plug, and there was an overflow of the system of filters for cleaning iron from water.

This experimental electrode block, made up of 75 titanium cathodes with an oxide-ruthenium coating and 75 of the same anodes, was tested by the Vodokanal MP in Tambov. The size of the electrodes is 330x330 mm, the distance between the opposite electrodes is 2 mm. The current strength of the electrolysis is 1400 A, the voltage is 6 V. The polarity of the electrodes was switched every 12 hours of electrolysis. The active chlorine productivity was 200 g / h. The water supply was about 1000 m ³ / h. Overgrowth of the interelectrode space by sediment did not occur over the entire period of testing for several months. The same electrode block, but with titanium cathodes (without an oxide-ruthenium coating) was overgrown with sediment after a week of continuous electrolysis without reverse current.

Claims (2)

 1. Installation for producing hypochlorite solutions by electrolysis, including a housing with inlet and outlet pipes, a gas outlet pipe, an electrode unit having titanium oxide-ruthenium-coated anodes, characterized in that titanium oxide-ruthenium-coated titanium cathodes are used in hard water electrolysis, which provides sediment removal without stopping the installation by reversing the current.  2. Installation according to claim 1, characterized in that for a more efficient gas removal when placing the electrode block in the main conduit in front of the clean water tank, there is an additional gas outlet connected to the bend of the knee in its lower part, the conduit being a knee consisting of a horizontal the part in which the electrode block and the partition are installed, providing flooding of the electrodes and the vertical part directed directly to the clean water tank.