RU98755U1 - ELECTROLYSIS INSTALLATION - Google Patents

Abstract

1. An electrolysis plant for the production of sodium hypochlorite, consisting of a tank for dissolving sodium chloride, the inlet pipe of which is connected to a water supply unit for dilution, and the outlet pipe is connected to a dosing pump for supplying the initial solution of sodium chloride to the electrolyzer, the outlet of which is connected to a tank for storage of the resulting sodium hypochlorite, wherein the tank is equipped with a pipe for ejecting hydrogen into the atmosphere and a pipe connected to the dosing pump for supplying sodium hypochlorite for water disinfection, characterized in that the water supply unit for diluting sodium chloride and the initial solution is equipped with an ion-exchange softener that removes hardness salts in water (calcium and magnesium salts) and preventing the formation of lime deposits in the electrolyser and in the water supply system of the electrolysis plant. ! 2. The electrolysis plant according to claim 1, characterized in that the storage tank for the resulting sodium hypochlorite is equipped with a pressure fan with a pipe for forced release of hydrogen into the atmosphere.

Description

The utility model relates to the field of engineering, in particular to the designs of electrolysis plants.

Known flow electrolyzer to obtain a solution of sodium hypochlorite from a solution of sodium chloride. A flow-through electrolyzer consists of a tank with inlet and outlet nozzles located on opposite walls. The vessel contains groups of monopolar and bipolar vertical plate electrodes. Depending on the concentration of the sodium chloride solution, to ensure the most efficient operation of the electrolyzer, the size of the interelectrode gaps between the plate electrodes is selected from the interval from 1 mm to 3 mm.

When installing plate electrodes at a short distance from each other, the problem arises of cleaning the electrodes from deposits of hardness salts that accumulate during electrolysis on the surfaces of plate electrodes.

The use of mechanical devices, such as scrapers, is difficult and inefficient and requires the removal of cassettes from the electrolytic tank and the presence of a special cleaning tool.

The use of means for supplying compressed gas to the interelectrode space according to patent RU 16504 U1 does not completely solve the problem of eliminating the formation of deposits of hardness salts since you still have to periodically rinse the electrolyzer with a hydrochloric acid solution.

The basis of this utility model is the task of creating the design of an electrolysis plant, which prevents the formation of deposits of hardness salts in the electrolyzer and in the water supply system of the electrolysis plant, as well as increasing the safety of operation by forced removal of hydrogen into the atmosphere.

The problem is solved in that the electrolysis unit is equipped with a means of softening the water entering the installation inlet. In the proposed utility model, a water softener is used with loading from a special cation exchange resin.

When the excess content of hardness salts in the source water (calcium and magnesium salts) exceeds 4.5 mEq / l, an intensive accumulation of calcareous deposits occurs in the electrolyzer and in the water supply system of the electrolysis unit. This leads to cost overruns, frequent flushing of the electrolyzer with hydrochloric acid solution, and more rapid failure of the electrolysis unit. Lime deposits also serve as a favorable environment for the reproduction of various microbes.

A water softener based on ion-exchange technologies ensures high-quality removal of hardness salts from water and prevents the formation of deposits. The ion exchange resin used in the softener also absorbs other soluble impurities, primarily compounds of iron, manganese and other metals. Softening is carried out to a residual hardness of 1.0-1.5 mEq / l, which corresponds to Russian and foreign standards for the operation of household and industrial equipment.

Technological schemes of electrolysis plants operating on sodium chloride solutions can be either flow-through or with a batch system. The main difference between the parameters of flow electrolysers and the parameters of batch electrolysers is that in the first case, the electrolysis process can be considered stationary, time-independent. Moreover, if the brine flow rate and the current load on the cell remain constant, then the concentration of the sodium hypochlorite solution removed from the cell remains unchanged.

In batch electrolysis plants, the concentration of sodium hypochlorite depends on the time elapsed since the start of electrolysis. In this case, the maintenance personnel should spend much more time on the organization of the process due to the fact that he is forced to fill the electrolyzer several times a day with a solution and drain sodium hypochlorite from them.

As a rule, the initial solution should contain at least 30 g / l sodium chloride, and to increase the yield of chlorine, cascade inclusion of electrolyzers is used.

Known electrolysis installation "Sea clor" company "De Nora" for the production of sodium hypochlorite from sodium chloride. A concentrated brine is prepared in the salt dissolving tank, which is then diluted to a predetermined concentration in the intermediate tank. The solution is pumped by a metering pump through a mesh filter into the electrolyzer or sequentially into a series of electrolyzers. The sodium hypochlorite obtained by electrolysis is collected in a storage tank. Electrolysis gases are removed after each electrolysis cell into a gas separator, and then into the atmosphere. Sodium hypochlorite in the treated water is supplied by a metering pump. Power supply of electrolyzers is carried out from the rectifying unit. The installation is equipped with automation elements that turn off the rectifier unit in violation of the technological mode of operation of the installation. Periodically, as the electrodes are overgrown with deposits of hardness salts, the electrolyzer is washed with a closed acid loop. (G.L. Medrish et al. "Disinfection of natural and waste waters using electrolysis", "Stroyizdat", M. 1982, p.31) The content of active chlorine in the finished product is 5-6 g / l. Higher chlorine concentrations (up to 8 g / l) can be achieved by partial recirculation of the solution, which increases energy consumption.

To increase the yield of the liquid-phase target solution obtained by electrolysis of the initial salt solution, after the first stage of electrolysis of the initial highly concentrated salt solution, include the subsequent electrolysis of the solution obtained in the previous stage when diluted with water (RF patent 2125120). The implementation of this method is given in the patent of the Russian Federation 2134733.

Known electrolysis installation OSEC company "WALLACE & TIERNAN". Protected by UK patent 2068016A with a priority of July 1, 1980 (by the date of the convention patent application being filed in England), but the invention itself was created in the USA, protected by US patent No. 42448690 with priority July 28, 1980, published February 03, 1981. The electrolysis installation includes four series-connected electrolysers consisting of several electrode cells.

The implementation of the proposed utility model is considered on the example of the technological scheme of the electrolysis installation in figure 1. All water entering the electrolysis plant passes through an ion-exchange softener 1, a water supply unit for diluting concentrated brine of salt located in the tank 2, a filter 3, a metering pump 4, a controlled valve 5 installed on the pipeline 6, provide a given flow rate of the supplied water controlled by a flowmeter 7. The electrolyzer is powered by a rectifier 8. The output of the electrolyzer is connected by a pipe 9 to a buffer tank 10 for storing the finished sodium hypochlorite. The buffer tank is equipped with a pipe 11 and an air duct 12, reaching a length of several tens of meters, to release gaseous products of electrolysis (hydrogen) into the atmosphere, a pipe 13 for supplying air pressure from the pressure fan 14 to force the removal of hydrogen into the atmosphere, because hydrogen can accumulate in air duct and pipe 15 for supplying sodium hypochlorite with a metering pump 16 to the points of entry for disinfection of water.

Improving the operational safety of the electrolysis plant is achieved by eliminating the accumulation of hydrogen in the long duct of the duct.

From the above description it is clear that the proposed utility model can be implemented not only in accordance with the considered example of its implementation, but also in other specific forms without deviating from its essence, as defined by the attached formula of the utility model.

Claims (2)

1. An electrolysis installation for the production of sodium hypochlorite, consisting of a container for dissolving sodium chloride, the inlet pipe of which is connected to a water supply unit for dilution, and the output pipe is connected to a metering pump for supplying an initial solution of sodium chloride to the electrolyzer, the outlet of which is connected to the reservoir for storing the obtained sodium hypochlorite, and the tank is equipped with a pipe for the release of hydrogen into the atmosphere and a pipe connected to the metering pump for supplying sodium hypochlorite for disinfection during s, characterized in that the water spout for dilution of sodium chloride and stock solution equipped with an ion exchange softener, ensuring removal of hardness salts in water (calcium and magnesium salts) and prevents the formation of lime scale in the electrolytic water supply system and the electrolysis unit. 2. The electrolysis installation according to claim 1, characterized in that the storage tank for the obtained sodium hypochlorite is equipped with a pressure fan with a pipe for the forced release of hydrogen into the atmosphere.