RU2176989C1 - Electrochemical module cell for treatment of aqueous solutions, plant for production of products of anodic oxidation of solution of alkaline or alkaline-earth metal chlorides - Google Patents

Abstract

FIELD: water treatment and purification. SUBSTANCE: invention deals with electrochemical treatment of water and/or aqueous solution in processes of purification and disinfection of water, processes associated with electrochemical regulation of acidic-basic and redox properties and catalytic activity of water and/or aqueous solution and also processes of electrochemical production of various chemical products by electrolysis of aqueous solutions, particularly, mixture of oxidants in electrolysis of aqueous solution of alkaline or alkaline-earth metal chloride. Electrochemical module cell for treatment of aqueous solutions has vertical coaxial cylindrical internal hollow and external electrons, lower and upper dielectric bushings with holes along their axes, and inlet and outlet channels brought to bushing surfaces and communicating with chamber of external electrode. Made in cell is diaphragm of ceramics based on zirconium oxide. Diaphragm is coaxially installed between electrodes and separate interelectrode space into electrode chambers. Internal hollow electrode has perforation holes. Inlet and outlet branch pipes of internal electrode chambers are made of conducting material and have appliances for fastening and sealing of diaphragm. Inlet and outlet branch pipes of internal electrode chamber are installed on lower and upper end faces of internal hollow electrode, respectively, and communicating with its cavity. Inlet and outlet branch pipes are sealed in axial holes of lower and upper dielectric bushings. Lower and upper dielectric bushings are installed and fixed on end faces of external electrode. Plant for preparation of products of anodic oxidation of chlorine solution has at least one electrochemical reactor made of one or more electrochemical module cells. Appliance for raising pressure is connected with inlet of anode chamber cells. Unit of initial solution supply is connected with anode chamber inlet. Cathode chamber circulating circuit of cells is connected with inlet and outlet of cathode chamber and has gas-separating vessel. Reactor cells are of similar type, connected in parallel and installed at the same level. Plant additionally has regulator of chloride solution level in anode chambers. EFFECT: simplified design and extended functional potentialities. 30 cl, 3 dwg, 1 tbl, 3 ex

Description

 The invention relates to the field of chemical technology, in particular to devices for the electrochemical treatment of water and / or aqueous solutions, and can be used both in the processes of water purification and disinfection, and in processes associated with the electrochemical regulation of acid-base, redox properties and catalytic activity of water and / or aqueous solutions, as well as in the processes of electrochemical production of various chemical products by electrolysis of aqueous solutions, in particular, a mixture of oxidane during electrolysis of an aqueous solution of alkali or alkaline earth metal chlorides.

State of the art
In applied electrochemistry, electrolyzers of various designs are used both for the treatment of water and / or aqueous solutions, and for the electrolytic production of various products, in particular flow electrolyzers with flat electrodes [1] or electrolyzers with coaxially arranged cylindrical electrodes and a diaphragm between them [2].

 The most promising are modular electrolyzers, which achieve the required performance by connecting the required number of electrochemical modular cells, which reduces the cost of designing and manufacturing electrolyzers of fixed capacity, unifies parts and assemblies, and reduces the time of installation and repair of such electrolyzers.

 The closest in technical essence and the achieved result is an electrochemical modular cell containing coaxially placed cylindrical external and internal hollow electrodes and a coaxially ultrafiltration diaphragm made of ceramic based on zirconium, aluminum and yttrium oxides installed between them [3]. This technical solution is selected as a prototype.

 In a known solution, the electrodes and the diaphragm are fixed in special dielectric bushings and heads, the latter being mounted rotatably. In the bushings and heads channels are made for supplying to the electrode chambers and for removing the treated aqueous solution from them. In the technical solution, preferred cell sizes are indicated. Water or an aqueous electrolyte solution is treated with a single or multiple (using an external circulation circuit) flow through the electrode chambers of the cell from the bottom up. Devices of the required performance are assembled from the required number of electrochemical modular cells.

 When using the well-known electrochemical modular cell, effective treatment of water or aqueous solutions is achieved with low energy consumption. The device is quite simple to operate, relatively easily combined into blocks, which are flow diaphragm electrochemical reactors of a given capacity (power).

 However, the known device has several disadvantages. When deep (more than 5000 C / l) treatment of aqueous electrolyte solutions with a concentration of 10 g / l or more, there is a need to use an external circulation circuit, with the help of which electrolysis gases are separated and the electrolyte solution is returned to the electrode chamber. In this case, difficulties arise in ensuring a uniform distribution of the flow of the returned electrolyte solution into the electrode chambers of the electrochemical modular cells combined into a block, i.e. into an electrochemical reactor of high power. This is due to the influence of capillary forces and differences in hydraulic resistance of narrow concentrically located electrode chambers of the cells during intense gas evolution at the electrodes.

 The diaphragm of the electrochemical cell is fixed and sealed with seals made of elastic acid-base material. However, most elastic polymeric materials under conditions of intensive electrolysis of concentrated aqueous solutions of alkali or alkaline earth metal chlorides lose their elasticity under the influence of liquid and gaseous electrolysis products. In a well-known electrochemical cell operating at a current strength of 8 - 10 A on concentrated (more than 10 g / l) chloride solutions, over time the tightness in the places where the diaphragm is fixed may be impaired, which leads to a deterioration in the performance of a reactor based on electrochemical modular cells.

 There is also known an apparatus for producing products of anodic oxidation of alkali metal chloride solutions, containing at least one cell, which is described above, cathodic and anodic circulation circuits, each of which is equipped with a gas separation vessel, an alkali metal chloride solution feed line connected through a pressure increase device, with anode circulation circuit. The gas outlet of the gas separation capacity of the anode circuit can be connected to a mixer, which allows to obtain oxidation products not only in gaseous form, but also in the form of an aqueous solution [4].

 The well-known installation, made by the modular principle, makes it relatively easy to assemble plants of various capacities, depending on the requirements to obtain products in the form of gas or solution. However, the known installation is relatively cumbersome, has two circulating circuits, and the gas separation tanks that are equipped with these circuits have additional requirements for the volume and height of their placement relative to the cells, which leads to an increase in the dimensions of the installation. Special requirements are imposed on the materials of pipelines and assemblies that form the anode circulation circuit, since during operation they are subjected to continuous exposure to a very chemically aggressive gas-liquid medium moving at a considerable speed. The presence of two circulation circuits with many interfaces also creates an additional risk of depressurization. The fact that the anode circuit operates under pressure places additional demands on the materials.

Disclosure of Invention
The aim of the invention is to simplify the design of the cell and providing the ability to arrange the required number of cells in a smaller space, simplifying the fixation nodes of the cell elements while increasing reliability, as well as expanding the functionality of the cell, which is achieved by providing the ability to organize and control the electrolyte circulation process along the height of the cell. Another objective of the invention is to simplify the installation for the production of anodic oxidation products, reduce its cost, reduce the size and increase reliability by reducing the degree of negative interference of the cells combined into an electrochemical reactor of high power.

 This goal is achieved by the fact that in an electrochemical modular cell for processing aqueous solutions containing vertical cylindrical coaxially placed internal hollow and outer electrodes and a diaphragm made of zirconia ceramic, coaxially mounted between the electrodes and dividing the interelectrode space into the electrode chambers, the input and output nozzles chambers of the internal and external electrodes, and means for mutually fixing the position of the cell elements, the internal hollow electrode is made with perforations, the inlet and outlet nozzles of the inner electrode chamber are made of electrically conductive material and are equipped with devices for attaching and sealing the diaphragm, the inlet and outlet nozzles of the inner electrode chamber being mounted respectively on the lower and upper ends of the inner hollow electrode and communicate with its cavity. The diaphragm is mounted coaxially with the inner electrode in the fixtures for attaching it, and the internal electrode, with the diaphragm mounted on it, is mounted coaxially with the external. In this case, the inlet and outlet nozzles of the inner electrode chamber are hermetically placed in the axial holes of the lower and upper dielectric bushings, the bushings themselves are hermetically mounted at the ends of the outer electrode, and the input and output channels communicating with the outer electrode chamber are respectively brought to the surface of the bushings.

 The implementation of a hollow internal electrode with holes allows you to organize the circulation of the electrolyte inside the electrode chamber due to gas lift. Placing inlet and outlet nozzles at the ends allows not to disturb the steady-state circulation process when new batches of electrolyte arrive, and also leads to a decrease in the hydraulic resistance of the cell.

 The inlet pipe of the inner electrode chamber is connected to the lower part of the hollow inner electrode by a welded or threaded connection, and the outlet pipe is connected to the upper part of the hollow inner electrode by a threaded or welded connection, respectively.

 Such fastening of the nozzles allows to ensure a reliable connection of the nozzles with the body of the electrode, and also creates the opportunity to ensure the supply of current to the electrode.

 Grooves for sealing gaskets are made on the inlet and outlet nozzles of the inner electrode chamber and on the side surfaces of the lower and upper dielectric bushings, and ledges are made on the side surfaces of the upper and lower bushings, in which the outer electrode is fixed with these gaskets.

 Placing the gaskets in the grooves allows you to fix their position, simplifies the installation and dismantling of the cell and ensures the integrity of the structure.

 In addition, the input and output channels of the chamber of the external electrode, respectively made in the lower and upper dielectric bushings, can be equipped with nozzles. These pipes can be made removable, fixed with elastic gaskets.

 The presence of removable nozzles allows you to rationally place cells in space, depending on the conditions of the problem.

 The fixture for fixing the ceramic diaphragm is made in the form of supporting disks, on one side of which protrusions and / or grooves are made for fixing the ceramic diaphragm in them, and on the other side of the supporting disks protrusions are made for fixing the fixing tool during installation and sealing of the diaphragm, as well as dismantling the cell.

 The support discs may be made of electrically conductive material. In this case, if the lower and / or upper dielectric bushings are installed with a gap relative to the surface of the support disks, the surface of the support disks on the side of the bushes and the side surfaces of the support disks adjacent to the diaphragm are provided with a dielectric coating.

 Such a dielectric coating of the surface of the support discs can be made in the form of caps made of dielectric material with axial holes whose diameter is equal to the diameter of the inlet and outlet nozzles of the chamber of the inner electrode.

 Supporting disks make it possible to tightly and reliably fix the diaphragm, ensure the constancy of its position during installation and operation of the cell and reliable tightness, which improves the functionality of the device by providing the possibility of using interchangeable diaphragms of different diameters in one cell while maintaining ease of installation, dismantling and repair.

 Means for the mutual fixation of the position of the cell elements are made in the form of washers and nuts located on the inlet and outlet pipes of the inner electrode chamber.

 Perforation holes are made in the upper and lower parts of the hollow inner electrode.

 Also, the hollow electrode can be made with additional perforation holes evenly spaced along the length of the hollow inner electrode and the axis of the holes are located along a helical line on its side surface or on a straight line forming the outer cylindrical surface of the line.

 The location and size of the perforations are selected depending on the requirements for creating the necessary conditions for the circulation of electrolyte inside the electrode chamber. In addition, as in the case of diaphragms, it is possible to easily and quickly replace one electrode with another in the cell, which is especially valuable when using cells in research works.

The geometric dimensions of the cell are determined by the interelectrode distance (hereinafter referred to as the MED). To obtain the products of anodic oxidation, it is advisable to use cells with an MER of 8-10 mm, and at the same time
d = 1.5-2.3 MED;
D = 3.0-4.3 MED;
L _d = 25-40 MED,
δ = 0.15-0.35 MED;
S _k ≥ S _a ,
where d is the outer diameter of the inner electrode,
D is the inner diameter of the outer electrode,
L _d is the length of the inner electrode,
δ is the thickness of the side walls of the diaphragm,
S _k is the cross-sectional area of the chamber of the outer electrode,
S _a - the cross-sectional area of the chamber of the inner electrode.

 The indicated cell sizes are optimal. With an increase in size, energy consumption increases, the complexity of sealing the cell elements increases, and the risk of rupture of the diaphragm under the influence of a pressure differential increases. With a decrease in size, the intensity of the circulation of the electrolyte inside the electrode chamber decreases, which leads to a decrease in the yield of the target products.

 The cell diaphragm is made of ceramic based on zirconium, aluminum, and yttrium oxides, and may contain additives of niobium, tantalum, titanium, gadolinium, and hafnium oxides. In this case, the diaphragm is ultra-, micro- or nanofiltered.

 Such a diaphragm is resistant to an aggressive environment in which electrochemical processes take place, has a constant size and characteristics. The use of such a diaphragm depending on the pore size allows you to directionally influence the flow of processes in the cell.

 The electrochemical modular cell made according to the invention can be used in various electrochemical processes, and, in particular, in the production of anodic oxidation products of aqueous solutions of alkali or alkaline earth metal chlorides. In carrying out this process, electrochemical modular cells are the main part of the installation to obtain the target product. In addition, since it is known that diaphragms with sufficiently small pore sizes work in the electrolysis of an aqueous solution of sodium chloride in order to produce chlorine as ion-exchange membranes, the use of the proposed cells with ceramic diaphragms with constant characteristics, and in particular a constant pore size, allows their use to take advantage of the membrane method of producing chlorine.

 An apparatus for producing products of anodic oxidation of a solution of alkali or alkaline earth metal chloride contains at least one electrochemical reactor made of one or more electrochemical modular cells with a cylindrical cathode, anode and a diaphragm made of zirconia-based ceramic placed between the electrodes coaxially placed in each of them and dividing the interelectrode space into the anode and cathode chambers, each of which has a separate input and output, located respectively the lower and upper parts of the cells, a device for increasing pressure, connected to the input of the anode chamber of the cell, a unit for preparing the initial solution, also connected to the input of the anode chamber, the circulation circuit of the cathode chamber, connected to the input and output of the cathode chamber and containing a gas separation vessel, a gaseous discharge line products of the anode chamber, a line for the removal of gaseous products of the cathode chamber, each electrochemical modular cell containing an internal cylindrical hollow anode, and an external circuit the cylindrical cathode, the lower and upper dielectric bushings, along the axis of which the holes are made, and the input and output channels communicating with the cathode chamber respectively are output to the surface of the bushings, the anode chamber is equipped with inlet and outlet pipes, the input and output pipes of the anode chamber made of electrically conductive material and equipped with devices fixed thereon for fastening and sealing the diaphragm, and the inlet and outlet nozzles of the anode chamber are mounted respectively on the lower and upper the ends of the anode and communicate with its cavity, the ceramic diaphragm is mounted coaxially to the anode in the devices for attaching the diaphragm, the anode with the attached diaphragm is mounted coaxially to the cathode, the inlet and outlet nozzles of the anode chamber being sealed in the axial holes of the lower and upper dielectric bushings and the lower and upper dielectric bushings are installed and fixed at the ends of the cathode, the anode is made with perforations located in the upper and lower parts of the anode, or evenly along the anode line, and the axis of the holes are located on a helical line or on a straight line forming a cylindrical surface of the anode line, the gaseous product exhaust line is connected to the outlet pipe of the anode chamber, the cells of the reactor or reactors are made of the same type, are connected in parallel and are all installed at the same level, and the installation further comprises a regulator of the level of chloride solution in the anode chambers.

 In an installation in an electrochemical module cell, the inlet pipe of the anode chamber is connected to the lower part of the hollow anode by a welded or threaded connection, and the output pipe is connected to the upper part of the hollow anode by a threaded or welded connection, respectively.

 Grooves are made on the inlet and outlet nozzles of the cell anode chamber and on the side surfaces of the lower and upper dielectric bushings to accommodate the gaskets.

 In the installation in the electrochemical module cell, the input and output channels to the cathode chamber are respectively made in the lower and upper dielectric bushings and are equipped with nozzles.

 In each electrochemical module cell of the installation, the device for attaching the ceramic diaphragm is made in the form of support disks, on one side of which protrusions and / or grooves are made for fixing the ceramic diaphragm in them, and on the other side of the support disks protrusions are made for fixing the fixing tool during installation and sealing the diaphragm, as well as when removing the cell.

 The support disks of the cells in the installation are made of electrically conductive material, and the lower and / or upper dielectric bushings are installed with a gap relative to the surface of the support disks, while the surface of the support disks on the side of the bushes and the side surfaces of the support disks adjacent to the diaphragm are provided with a dielectric coating. This coating of the surface of the supporting discs is made in the form of caps made of dielectric material with axial holes whose diameter is equal to the diameter of the inlet and outlet nozzles of the chamber of the inner electrode.

The installation contains cells in which the anode and cathode are installed with an interelectrode distance - MER - 8-10 mm, and
d = 1.5-2.3 MED;
D = 3.0-4.3 MED;
L _d = 25 - 40 MED,
δ = 0.15-0.35 MED;
S _k ≥ S _a ,
where d is the outer diameter of the anode,
D is the inner diameter of the cathode,
L _d is the length of the cathode,
δ is the thickness of the side walls of the diaphragm,
S _k is the cross-sectional area of the cathode chamber,
S _a is the cross-sectional area of the anode chamber.

 The cell diaphragm is made of ceramic based on zirconium, aluminum and yttrium oxides, and contains additives of niobium, tantalum, titanium, gadolinium and hafnium oxides, and can be ultra-, micro- or nanofiltered.

 The use of cells according to the invention makes it possible to organize intensive circulation of the anolyte in the anode chamber and simplify installation by eliminating the external anode circulation circuit. Due to the exclusion of the anode circuit, labor costs for installation and repair of the installation associated with the replacement of individual cells are also reduced. In addition, by adjusting the level of chloride solution in the cells, it is possible to change the productivity in a plant with a fixed number of cells and obtain only the amount of oxidation products that is necessary at the moment, which is especially favorable when using the plants in conditions requiring a variable amount of oxidizing agents.

 The device for increasing the pressure can be made in the form of a pump, the pressure line of which is connected to the inlet of the anode chamber, and the suction line to the unit for preparing the initial solution.

 The unit for preparing the initial solution is made in the form of a container for dissolving a solid salt in water or for mixing a concentrated solution of chloride with water and the tank is equipped with devices for introducing an alkaline reagent, for removing sediment, and a device for introducing acid.

 The apparatus for producing products of anodic oxidation of a solution of alkali or alkaline earth metal chlorides may further include a unit for preparing gaseous hydrogen chloride containing a device for supplying reagents and a device for withdrawing gaseous hydrogen chloride, and the device for supplying reagents is connected to lines for removing gaseous products from the anode chamber and from gas separation capacity of the cathode circuit.

 The installation also contains a node for dissolving gaseous hydrogen chloride in water, with devices for introducing reagents and a device for draining a solution of hydrochloric acid, and devices for introducing reagents are connected to the fresh water supply line and with a device for removing gaseous hydrogen chloride gas from the unit for its preparation, and the device for draining a solution of hydrochloric acid is connected to a storage tank and, through this tank, with a device for supplying acid to the unit for preparing the initial solution, which can be made in the form of a pump, and at the same time serve to create pressure in the system.

 The installation may also further comprise a buffer tank mounted on the circulation circuit of the cathode chamber, the buffer tank being connected via a metering pump to a device for introducing an alkaline reagent of the tank for dissolving solid salt in water.

 This embodiment makes it easier to operate the plants, with small dimensions expand the range of products obtained, adjust their properties depending on the conditions of the problem being solved. In addition, the resulting products, in particular acid, can be used to flush plants.

Brief Description of the Drawings
The cell according to the invention is shown in FIG. 1.

 In FIG. 2 is a diagram of an apparatus for producing anodic oxidation products of an aqueous solution of an alkali or alkaline earth metal chloride, and FIG. 3 schematically shows a plant, the reactor of which consists of five cells.

 The electrochemical modular cell for processing aqueous solutions (Fig. 1) contains a vertical cylindrical inner hollow electrode 1 and an external electrode 2. At the ends of the electrode 2 there are lower 3 and upper 4 dielectric bushings, the axes of which are made holes, and the input surface is respectively exposed to the bushings and output channels communicating with the camera of the external electrode and provided with removable nozzles 5 and 6, respectively. The diaphragm 7 is made of zirconium oxide ceramic, coaxially mounted between electrodes 1 and 2.

 The input 8 and output 9 pipes of the chamber of the inner electrode 1 are installed at the ends of the electrode 1. The pipe 8 is connected to the electrode 1 by a threaded connection, and the pipe 9 is welded.

 The electrode 1 is made with perforations 10 located in the upper and lower parts of the electrode 1, as well as with additional holes 10, the axes of which are located along a helical line on the generatrix of the electrode 1.

 The diaphragm 7 is installed coaxially to the inner electrode in devices for its fastening, which are made in the form of supporting disks 11 and 12 of an electrically conductive material using a seal 13 made of a material resistant under electrolysis conditions, for example fluoroplastic. On one side of the support disks 11 and 12, protrusions 14 are made for fixing a ceramic diaphragm therein, and on the other side of the support disks, protrusions 15 are made for interacting with a fixing tool.

 The lower 3 and upper 4 dielectric bushings are installed with a gap relative to the surface of the supporting disks 11 and 12, and the surface of the supporting disks 11 and 12 from the side of the bushes and the side surfaces of the supporting disks adjacent to the diaphragm are provided with caps 16 and 17 of dielectric material with axial holes, the diameter of which is equal to the outer diameter of the input 8 and output 9 nozzles of the chamber of the inner electrode.

 At the input 8 and output 9 pipes of the inner electrode chamber and on the side surfaces of the lower 3 and upper 4 dielectric bushings, grooves are made to accommodate the elastic gaskets 18.

 Also, washers 19 and nuts 20 are located at the input 8 and output 9 pipes of the inner electrode chamber.

 The cell works as follows.

 Through nozzles 5 and 8, the medium to be treated enters the chambers of the outer 2 and inner 1 electrodes, respectively, separated by a diaphragm 7. In the chamber of the inner electrode, the solution fills the cavity of the electrode 1 and enters the space between the diaphragm 7 and the outer surface of the electrode 1. After applying voltage to the outer surface electrode 1 begins the intense release of electrolysis gases, and gas bubbles carry the electrolyte up. If the perforation holes 10 are located only in the upper and lower parts of the electrode 1, then through the lower holes 10 the electrolyte enters the space between the diaphragm 7 and the outer surface of the electrode 1, and through the upper holes 10 it is discharged into the internal cavity of the electrode and is removed through the pipe 9 from the cell. Since electrolysis does not occur on the inner surface, the electrolyte inside the hollow electrode is less saturated with gas bubbles and has a greater apparent density, which leads to the organization of the internal circulation of the electrolyte in the chamber of the hollow electrode 1.

 If it becomes necessary to control the cell performance by changing the electrolyte level in the inner electrode chamber, an electrode 1 with perforation holes 10 and additional perforation holes 10 is used. In this case, in the case of empty space, only electrolysis gas is removed from the nozzle 9, and the electrolyte circulates in the inner electrode chamber 1.

 In the chamber of the outer electrode 2, the electrolyte enters the processing through the pipe 5, and passing the chamber of the electrode 2 from the bottom up, it is output through the pipe 6. The circulation of the electrolyte in the chamber of the external electrode can be organized only through an external circulation circuit.

 Installation for producing products of anodic oxidation of a chloride solution (Fig. 2, 3), contains an electrochemical reactor made of electrochemical modular cells 21 connected in parallel. The electrochemical cells are separated by a diaphragm 7 into the anode 22 and the cathode 23 of the chamber. A device for increasing pressure 24, a container 25 for dissolving a solid salt in water or for mixing a concentrated solution of chloride with water, a container 26 of the cathode circulation loop, an anode gas pressure regulator 27 "to itself", a device for producing gaseous hydrogen chloride 28, a buffer tank for catholyte 29, a container (reactor) for dissolving gaseous hydrogen chloride 30, a storage tank for hydrochloric acid 31, a storage tank for catholyte 32, a storage tank for the initial salt solution and 33, a regulator of the anolyte level in the cells 34 to the control unit 35, the gas-liquid mixer 36, catholyte pump 37, control valves and a connecting armature.

 Installation works as follows.

 A solid salt or concentrated sodium chloride solution and water are supplied to the container 25. If necessary, an alkaline reagent is provided from the cathode circuit of the cells 21. From the tank 25, the initial chloride solution, the concentration of which is determined by the conditions of the problem being solved, enters the storage tank 33, and then into the device for increasing the pressure 24, for example, a pump, and is supplied under excessive pressure into the anode chamber 22 of the cells 21 with a speed that ensures the constancy of a given level of anolyte in cells 21. The level of anolyte is supported by means of a device 34 connected by a control unit 35 with Blenheim 24 to increase the pressure.

 After applying voltage to the electrodes in the anode chamber 22 on the outer surface of the hollow cylindrical anode begins the intense release of electrolysis gases, mainly chlorine. Due to the perforation holes of the cylindrical hollow anode, the anolyte enters the inner cavity of the anode, is freed from gas bubbles and thus an intensive internal circulation of the anolyte occurs. Gas (mainly chlorine) is taken from the upper part of the hollow anode and removed from the anode space through a pressure regulator 27. The obtained anode gas can be sent directly to the consumer, or fed to the gas-liquid mixer and supplied to the consumer in the form of an aqueous solution of oxidants.

 The cathode chamber 23 of the cells 21 is filled with water (or stock solution) before being turned on. After applying voltage to the electrodes, a pump 37 is turned on, which removes excess catholyte from the buffer tank 29. In the tank 26, the catholyte is freed from electrolysis gases, mainly hydrogen, and returned to the reprocessing. Hydrogen from the tank 26 is released into the atmosphere or enters the device 28 for the preparation of gaseous hydrogen chloride.

 Part of the chlorine through the pressure regulator also enters the device 28 for the preparation of hydrogen chloride. Obtained in the device 28, hydrogen chloride enters the mixer (reactor) 30, in which it is mixed with water, forming an aqueous solution of hydrochloric acid. An aqueous solution of hydrochloric acid from the mixer 30 is fed into the storage tank 31 and through the control valve enters the device 24 to increase the pressure. The supply of a hydrochloric acid solution to the anode chamber 22 of the installation can be carried out both in a mixture with the initial salt solution and without mixing, which allows cleaning the cathode chambers 23 of the installation from carbonate deposits without stopping its operation, i.e. without any disruption to continuous operation.

 Excess catholyte from tank 26 is discharged to tank 29, from which it can be supplied to tank 25 for preparing the initial solution in order to clean it of hardness ions and scale-forming metals. The main volume of catholyte enters the storage tank 32, from where it can be supplied to the disinfected water to the mixer 36, as shown in FIG. 2, for regulating the pH of water with anodic oxidation products dissolved in it. In addition, catholyte can be used for the preparation of reagents used in the preliminary chemical treatment of water - coagulants, flocculants, as well as for cleaning equipment (containers, filters) from contaminants. It is also possible to direct the catholyte, having a significant concentration of sodium hydroxide (up to 150 g / l), to evaporation in order to obtain solid commodity caustic soda.

Embodiments of the invention
The invention is illustrated by the following examples, which, however, do not exhaust all the possibilities of implementing the invention.

In all examples, a cell was used, the anode and cathode of which were installed with an interelectrode distance of MER = 10 mm. The outer diameter of the anode d was 16 mm (d = 1.6 MER), the inner diameter of the cathode D was 36 mm (D = 3.6 MER), the length of the cathode L _d was 350 mm (L _d = 35 MER), the diaphragm wall thickness δ was equal to 2 mm (δ = 0.2 MER), the cross-sectional area of the cathode chamber S _k was 4 cm ² , the cross-sectional area of the anode chamber S _a was 2.5 cm ² , i.e. S _k ≥ S _a . The ultrafiltration diaphragm was made of ceramic composition: zirconium oxide - 60%, alumina - 27% and yttrium oxide - 3%. On the surface of the anode along its entire height between the inlet and outlet openings, 9 holes were arranged with a pitch of 30 mm along a helical line. The surface of the titanium anode was coated with ORTA, the supporting disks for fixing the diaphragm, and also the nozzles were made of titanium grade VT1-00, the seals of the diaphragm were made of fluoroplastic grade F4.

 The upper and lower bushings mounted on the external electrode (cathode) were made of polystyrene. O-rings sealing the chamber of the outer electrode at the junction with the upper and lower bushings, as well as at the exit points of the nozzles of the inner electrode (anode) were made of acid-base rubber IRP-1314.

 Example 1. Installation AQUACHLOR, made in accordance with the present description of the invention and equipped with an electrochemical reactor of two modular electrochemical cells FEM-7, manufactured in accordance with the above description and installation AQUACHLOR-100, mass-produced in accordance with RF patent N 2088693, C 25 B 9/00, 1997, and equipped with an electrochemical reactor of 12 modular electrochemical cells PEM-3 (flow-through electrochemical modular cell, model 3), manufactured according to US patent N 5635040, C 02 F 1/461, 06/03/97, were investigated in P otsesse produce a mixture of oxidants (primarily chlorine) electrolysis of aqueous sodium chloride.

 The research results are shown in table 1.

 As can be seen from the table, the installation according to the invention has a higher productivity, lower energy consumption. Also, the installation, with higher performance, has smaller dimensions and weight. In addition, the power source used in the installation also has a lower mass. This difference in the mass of power sources is due to the fact that the source in the device according to the invention does not have a current control system, unlike the prototype source. The current in the invention is controlled by changing the level of the solution in the working (anode) chambers of the modular electrochemical cells making up the reactor.

 Example 2. The same settings were studied under the same conditions for the stability of the results obtained over time.

 After 2000 hours of operation, the oxidant productivity of the prototype plant falls by 10-30% due to a violation of the tightness of the diaphragm seals in the cells of the prototype plant, while the device according to the invention works while maintaining the operating parameters at the initial level.

Industrial applicability
The invention allows to simplify the design of the cell, to enable the process using the internal circulation of the electrolyte in one of the electrode chambers, provides the ability to adjust the cell performance by adjusting the electrolyte level in one of the chambers, to simplify the installation and dismantling of the cell, to ensure the layout of the required number of cells in a smaller space to simplify the fixation nodes of the cell elements while increasing their reliability. Using the installation for producing anodic oxidation products allows you to expand the range of products obtained, to obtain the target product in the form of a mixture of gases or in the form of an aqueous solution, to obtain gaseous hydrogen chloride or hydrochloric acid solution, to reduce the consumption of reagents for the process, to simplify the installation by eliminating the anode circulation loop .

Sources of information
1. US patent N 5427658, C 25 B 9/00, C 25 B 15/08, 1995.

 2. Japan Patent No. 02274889 A, C 25 B 9/00, 1989.

 3. US patent N 5635040, C 02 F 1/461, 06/03/97 (prototype).

 4. RF patent N 2088693, C 25 B 9/00, 1997 (prototype).

Claims (30)

 1. An electrochemical modular cell for the treatment of aqueous solutions, containing vertical cylindrical inner hollow and outer electrodes, lower and upper dielectric bushings, the axes of which are made holes, and the input and output channels communicating with the camera of the external electrode, the diaphragm from zirconium oxide-based ceramics, coaxially mounted between the electrodes and dividing the interelectrode space into the electrode chambers, the inlet and outlet nozzles of the internal chamber a morning electrode and means for mutually fixing the position of the cell elements, characterized in that the inner hollow electrode is made with perforations, the inlet and outlet nozzles of the chamber of the inner electrode are made of electrically conductive material and are equipped with devices for fastening and sealing the diaphragm, the inlet and outlet nozzles the inner electrode chambers are mounted respectively on the lower and upper ends of the inner hollow electrode and communicate with its cavity, the diaphragm mounted coaxially to the inner electrode in devices for mounting it, the inner electrode with a diaphragm mounted on it is mounted coaxially to the outer, and the input and output tubes of the chamber of the inner electrode are sealed in the axial holes of the lower and upper dielectric bushings and the lower and upper dielectric bushings are mounted and fixed at the ends external electrode.  2. The electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that the inlet pipe of the inner electrode chamber is connected to the lower part of the hollow inner electrode by a welded or threaded connection, and the outlet pipe is connected to the upper part of the hollow inner electrode by a threaded or welded connection .  3. An electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that grooves are made on the inlet and outlet nozzles of the inner electrode chamber and on the side surfaces of the lower and upper dielectric bushings.  4. An electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that steps are made on the lateral surfaces of the upper and lower bushes and the external electrode is fixed to them using gaskets.  5. The electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that the input and output channels into the chamber of the external electrode are made in the lower and upper dielectric bushings, respectively, and are equipped with nozzles.  6. An electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that the device for attaching the ceramic diaphragm is made in the form of supporting disks, on one side of which protrusions and / or grooves are made for fixing the ceramic diaphragm in them, and on the other projections for fixing the fixing tool during installation and sealing of the diaphragm, as well as when removing the cell, are made to the side of the support discs.  7. An electrochemical modular cell for processing aqueous solutions according to claim 6, characterized in that the support discs are made of electrically conductive material.  8. The electrochemical modular cell for processing aqueous solutions according to claim 7, characterized in that the lower and / or upper dielectric bushings are installed with a gap relative to the surface of the support discs, while the surface of the support discs from the side of the bushes and the side surfaces of the support discs adjacent to the diaphragm are equipped with a dielectric coating.  9. An electrochemical modular cell for processing aqueous solutions according to claim 8, characterized in that the dielectric coating of the surface of the support discs is made in the form of caps made of dielectric material with axial holes, the diameter of which is equal to the diameter of the inlet and outlet nozzles of the inner electrode chamber.  10. An electrochemical modular cell for processing aqueous solutions according to claim 1, characterized in that the means for the mutual fixation of the position of the cell elements are made in the form of washers and nuts located on the inlet and outlet nozzles of the inner electrode chamber.  11. An electrochemical modular cell for processing aqueous solutions according to any one of claims 1 to 10, characterized in that the perforations are made in the upper and lower parts of the hollow inner electrode.  12. The electrochemical modular cell for processing aqueous solutions according to claim 11, characterized in that the hollow electrode is provided with additional perforation holes uniformly along the length of the hollow inner electrode, and the axis of the additional holes are located along a helical line on its side surface or on a straight line forming outer cylindrical surface of the electrode, line. 13. The electrochemical modular cell for processing aqueous solutions according to any one of claims 1 to 12, characterized in that the cylindrical outer and inner electrodes are installed with an interelectrode distance of MER of 8-10 mm, and wherein
d = 1.5 - 2.3 MED;
D = 3.0 - 4.3 MED;
L _d = 25 - 40 MED,
δ = 0.15 - 0.35 MED,
S _k ≥ S _a ,
where d is the outer diameter of the inner electrode;
D is the inner diameter of the outer electrode;
L _d is the length of the inner electrode;
δ is the thickness of the side walls of the diaphragm;
S _k is the cross-sectional area of the chamber of the outer electrode;
S _a - the cross-sectional area of the chamber of the inner electrode.  14. An electrochemical modular cell for processing aqueous solutions according to any one of claims 1 to 13, characterized in that the diaphragm is made of ceramic based on zirconium, aluminum and yttrium oxides and contains additives of niobium, tantalum, titanium, gadolinium and hafnium oxides.  15. An electrochemical modular cell for processing aqueous solutions according to any one of claims 1 to 14, characterized in that the diaphragm is made ultra-, micro- or nanofiltered.  16. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals, containing at least one electrochemical reactor made of one or more electrochemical modular cells with a coaxially placed cylindrical cathode, an anode and a diaphragm made of zirconia-based ceramic mounted between electrodes and dividing the interelectrode space into the anode and cathode chambers, each of which has a separate input and output, respectively located in neither it and the upper parts of the cells, a device for increasing pressure, connected to the input of the anode chamber, a node for preparing the initial solution, also connected to the input of the anode chamber, the circulation circuit of the cathode chamber, connected to the input and output of the cathode chamber and containing a gas separation vessel, a gaseous product discharge line the anode chamber, the line of removal of gaseous products of the cathode chamber, characterized in that the electrochemical modular cell contains an inner cylindrical hollow anode and an external cylinder a datic cathode, lower and upper dielectric bushings, along the axis of which holes are made, and input and output channels communicating with the cathode chamber respectively are output to the surface of the bushings, the anode chamber is provided with inlet and outlet pipes, the input and output pipes of the anode chamber made of electrically conductive material and equipped with devices fixed thereon for fastening and sealing the diaphragm, and the inlet and outlet pipes of the anode chamber are mounted respectively on the lower and upper the ends of the anode and communicate with its cavity, the ceramic diaphragm is mounted coaxially to the anode in the fixture for attaching the diaphragm, the anode with the attached diaphragm is mounted coaxially to the cathode, the inlet and outlet nozzles of the anode chamber being sealed in the axial holes of the lower and upper dielectric bushings and the lower and upper dielectric bushings are installed and fixed at the ends of the cathode, the anode is made with perforations located both in the upper and lower parts of the anode, and evenly along the length of the anode, and the axis of the holes are located on a helical line on its lateral surface or on a straight line forming a cylindrical surface of the anode, the exhaust line of gaseous products of the anode chamber is connected to the outlet pipe of the anode chamber, and the cells of the reactor or reactors are made of the same type, are connected in parallel and all installed at the same level, and the installation additionally contains a regulator of the level of chloride solution in the anode chambers.  17. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the inlet pipe of the anode chamber is connected to the lower part of the hollow anode by a welded or threaded connection, and the output pipe is connected to the upper part of the hollow anode respectively threaded or welded joint.  18. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell on the inlet and outlet pipes of the anode chamber and on the side surfaces of the lower and upper dielectric bushings grooves are made to accommodate gaskets.  19. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the input and output channels into the cathode chamber are respectively made in the lower and upper dielectric bushings and are equipped with nozzles.  20. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the device for attaching the ceramic diaphragm is made in the form of supporting disks, on one side of which protrusions and / or grooves are made for securing a ceramic diaphragm in them, and on the other side of the supporting discs, protrusions are made for fixing the fixing tool during installation and sealing of the diaphragm, as well as when removing the cell.  21. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to claim 20, characterized in that in the electrochemical module cell supporting disks are made of electrically conductive material, and the lower and / or upper dielectric bushings are installed with a gap relative to the surface of the supporting disks, the surface of the supporting discs on the side of the bushings and the side surfaces of the supporting discs adjacent to the diaphragm are provided with a dielectric coating.  22. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to item 21, characterized in that in the electrochemical module cell, the dielectric coating of the surface of the supporting disks is made in the form of caps made of dielectric material with axial holes whose diameter is equal to the diameter of the input and output nozzles of the chamber of the internal electrode. 23. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the anode and cathode are installed with interelectrode distance - MER - 8-10 mm and
d = 1.5 - 2.3 MED;
D = 3.0 - 4.3 MED;
L _d = 25 - 40 MED,
δ = 0.15 - 0.35 MED,
S _k ≥ S _a ,
where d is the outer diameter of the anode;
D is the inner diameter of the cathode;
L _d is the length of the cathode;
δ is the thickness of the side walls of the diaphragm;
S _k is the cross-sectional area of the cathode chamber;
S _a is the cross-sectional area of the anode chamber.  24. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the diaphragm is made of ceramic based on zirconium, aluminum and yttrium oxides and contains additives of niobium, tantalum, titanium, gadolinium oxides and hafnium.  25. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that in the electrochemical module cell, the diaphragm is made ultra-, micro- or nanofiltered.  26. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that the device for increasing pressure is made in the form of a pump, the pressure line of which is connected to the input of the anode chamber, and the suction line to the unit for preparing the initial solution .  27. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that the unit for preparing the initial solution is made in the form of a container for dissolving solid salt in water or for mixing a concentrated solution of chloride with water and the tank is equipped with devices for input alkaline reagent, to remove sediment and a device for supplying acid.  28. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to clause 16, characterized in that it further comprises a unit for the preparation of gaseous hydrogen chloride, containing a device for supplying reagents and a device for outputting gaseous hydrogen chloride, and a device for supplying reagents connected to the lines of removal of gaseous products from the anode chamber and from the gas separation capacity of the cathode circuit.  29. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to p, characterized in that the installation contains a node for dissolving gaseous hydrogen chloride in water, with devices for introducing reagents and a device for draining a solution of hydrochloric acid, and devices for the input reagents are connected to the fresh water supply line and with a device for outputting gaseous hydrogen chloride of its preparation unit, and a device for draining a solution of hydrochloric acid Ota connected to storage capacity.  30. Installation for producing products of anodic oxidation of a solution of chlorides of alkali or alkaline earth metals according to paragraphs 27-29, characterized in that the installation further comprises a buffer tank connected to a gas separation tank and through a metering pump with a device for introducing alkaline reagent tanks for dissolving solid salt in water.

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