RU2511363C2 - Water decontamination station and control and separation device to be incorporated therewith - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: set of invention relates to water treatment. Proposed station comprises electrolytic tank with anode and cathode chambers separated by membrane, sodium chloride solution preparation assembly, water feed line, batchers, separators of anolyte and catholyte and ejector arranged in flow line. Batchers are composed by proportioning pumps with external control. One of the latter is arranged in sodium chloride solution feed line to feed aid solution to anode chamber inlet while another one is arranged in that feeding water to cathode chamber inlet. Anolyte separator at anode chamber inlet is equipped with air bleed element with hydraulic lock at its inlet. Note here that outlet gas discharge pipe of the separator is communicated with ejector suction pipe. Catholyte separator is arranged at cathode chamber outlet and communicated with alkali accumulator. Besides this device comprises anolyte and catholyte separators and hydraulic lock integrated in single unit. Said unit is arranged in transparent case divided by baffles into three chambers, i.e. anolyte separator, hydraulic lock and catholyte separator. Case sidewalls are furnished with check marks to control fluid level in said three chambers.

EFFECT: higher safety and reliability.

11 cl, 6 dwg

Description

FIELD OF THE INVENTION

The invention relates to the field of disinfection and water treatment, and more particularly to installations based on the use of membrane electrolysis of sodium chloride solution to produce chlorine and its subsequent use.

 State of the art

A known water disinfection station (see patent for invention RU 2281252, IPC: С02F 1/467, published on 08/10/2006), containing, like the claimed station, a membrane bipolar electrolyzer with anolyte and catholyte separators, a solution tank for preparing a chloride solution sodium and means for supplying it to the electrolyzer, a water supply line to the electrolyzer and an ejector for mixing the resulting chlorine with water.

The disadvantages of the known station should be attributed to the use of rotameters for supplying a solution of chloride in the electrolyzer, because flowmeters are prone to salt overgrowth, which leads to inaccurate dosing. As a result, frequent station stops are required to clean or replace them. The metering pump, which is not subject to the mentioned problem, in the mentioned solution is used only for supplying the salt solution to the storage tank, from where the solution is supplied to the electrolysis through rotameters.

To reduce the risk of chlorine emission into the atmosphere, the station provides a circulation loop of alkali supplied to the ejector for mixing with gaseous chlorine and water, however, this complicates the design of the installation and leads to the production of mainly sodium hypochlorite, which is known to be a weaker disinfectant for compared to chlorine.

A known electrolysis installation (see patent No. 93086, IPC: С25В 9/00 publ. 04/20/2010), containing an electrolyzer, the inlet of which is connected by means of a metering pump to a container for preparing a solution of sodium chloride, and the outlet is connected to the tank for the finished disinfectant used to disinfect water. The installation is characterized by a high level of automation due to the use of metering pumps for the supply of salt solution, automatic valves for the supply of water, various monitoring equipment and a processor for processing information and control. However, it is intended to produce sodium hypochlorite and cannot be used to produce chlorine, which is characterized by stronger bactericidal properties and the possibility of prolonged action.

As the closest in purpose and similar structural features analogue to the claimed water disinfection station, a constructive solution was adopted for the installation of a liquid chlorinating agent, disclosed in the materials of patent for invention RU 2090519, IPC: C02F 1/76, С25В 1/26, publ. 09/20/1997, the aforementioned installation contains an electrolyzer with anode and cathode chambers separated by a membrane partition, a site for the preparation of a solution of sodium chloride and a line for supplying water to the electrolysis associated with dosing devices. A catholyte separator is installed at the exit of the cathode chamber, which is connected with an alkaline storage tank. An anolyte separator is installed at the outlet of the anode chamber, which ensures the separation of gaseous chlorine obtained by electrolysis from the liquid phase of the anolyte. To intensify the separation process, the separator is equipped with an air intake pipe. The gas outlet pipe of the anolyte separator is connected to the suction pipe of the ejector installed in the flow line and providing a mixture of gaseous chlorine with water to produce a chlorinating agent.

A significant drawback of this solution is that it is possible that chlorine gas will be released through the air intake pipe of the anolyte separator into the station room, for example, when the ejector pump fails, while the dosing scheme of the water and electrolyte solution used in the installation makes it practically inoperative. Another disadvantage is the low efficiency of monitoring the health of the installation, due to the fragmentation of the monitored devices, which also reduces the safety of the installation.

Known separator unit, which is part of a device for generating combustible gas by electrolysis (see patent for invention RU 2404291, IPC: С25В 9/00, published on November 20, 2010), containing a separation chamber divided by partitions into many chambers made with holes in the bottom and partitions. The separator unit is installed between the upper part of the electrolytic cell and the sealing casing and serves to separate from the liquid a gas mixture of hydrogen and oxygen formed in the electrolytic cell. In fact, this separator block is similar to the anolyte separator or the catholyte separator in the above-described installation according to the patent RU 2090519, only has a more complex structure for performing multi-stage cleaning.

The applicant is not aware of the technical solutions of electrolysis plants in which there would be a unit combining anolyte separator, catholyte separator, and a safety device such as a water seal. The operation of the separators in the installations known to the applicant is controlled by visual inspection by the operator of the liquid level in each separator separately. The fragmentation of the aforementioned devices in known installations, for example, in the patent RU 2090519, makes it difficult to control the operation of the installation, causes a low efficiency of detection and troubleshooting.

Disclosure of invention

The problem to which the invention is directed is to eliminate the above-mentioned disadvantages and create a water disinfection station based on the use of membrane electrolysis of sodium chloride solution to produce chlorine, which is characterized by high operational reliability and production safety.

The technical result achieved by using the invention is to increase safety and operational reliability by eliminating the emission of chlorine gas into the room of the station, providing automation of the main production processes, as well as by increasing the efficiency of monitoring the operation of the station.

The aforementioned problem was solved in the design of the proposed water disinfection station, built on the basis of an electrolysis plant for producing chlorine, containing an electrolyzer with an anode and cathode chambers separated by a membrane, a sodium chloride solution preparation unit and a water supply line connected with dosing means, anolyte separator installed on the output of the anode chamber and equipped with an air intake element mounted on the output of the cathode chamber of a catholyte separator associated with an alkali accumulator, and an ejector installed in the flow line, the suction pipe of which is connected to the outlet gas outlet pipe of the anolyte separator.

New in the design of the proposed station is that it is equipped with a water trap installed at the inlet of the air intake element of the anolyte separator, and also that the means for dispensing water and electrolyte for electrolysis are made in the form of metering pumps, one of which is installed in the sodium chloride solution supply line to the input of the anode chamber of the electrolyzer, and the other in the water supply line to the input of the cathode chamber, while both metering pumps are made with the possibility of external control.

The air intake element of the anolyte separator forms a channel for supplying air. This can be a tube, a pipe segment — a pipe, and in the simplest case — an opening providing air access to the internal volume of the anolyte separator to intensify the separation process. In some cases, the air intake element may be connected to the air supply line.

In the claimed solution, the air intake into the anolyte separator is carried out through a water seal. A hydraulic lock (in short - a water lock), the same as a water lock, is a safety hydraulic device that prevents the backflow of gases (see. Great Soviet Encyclopedia. - M.: Soviet Encyclopedia, 1969-1978). In the simplest case, it can be a column of water blocking the passage channel in a siphon formed by a bend in the pipeline.

More reliable protection is provided by a water lock made in the form of a tank-chamber partially filled with water with an air supply tube, one end of which is immersed in water and the other is brought out to allow air intake. In this case, the air intake element communicates the internal volume of the anolyte separator with the internal volume of the said chamber above the water level in it.

In case of a malfunction of the ejection pump, when chlorine ceases to be sucked out of the anolyte separator by the ejector, and the electrolyzer continues to work, the so-called the reverse discharge, and the gas phase containing chlorine gas is displaced from the anolyte separator through the air intake element. Due to the fact that a water trap is installed at the inlet of the latter, the displaced chlorine enters the water, where it dissolves with the formation of chlorine water, without entering the station premises.

Gaseous chlorine entering the chamber volume of the water trap displaces part of the water from it into the air supply tube, as a result of which a water plug forms in the latter, which further prevents the exit of chlorine into the station room.

Thus, the presence of a water seal at the inlet of the anolyte separator separator eliminates the possibility of the discharge of gaseous chlorine from the electrolysis process into the station's room in the event of any malfunctions, thereby increasing the safety of staff.

The use of metering pumps with external control both in the supply line of sodium chloride solution and in the supply line of water for electrolysis makes it possible to fully automate the dosing processes of the mentioned initial components, and as a result, the automatic control of the electrolysis process and the operation of the plant as a whole. The mentioned automation allows, if not exclude, then significantly reduce the time of a person’s personal presence in the production area, which helps to increase the safety of work. In addition, the exclusion of the human factor, which depends on the qualifications and well-being of a particular employee, even from part of the work process, can improve the reliability of the station and its safety.

To solve this problem, the execution of the claimed control and separation device is also aimed, which can be used both in the proposed water disinfection station and in another similar station or electrolysis installation. The control and separation device comprises a transparent casing, divided by partitions into three chambers, in which an anolyte separator is provided, equipped with an air intake element, a water trap and a catholyte separator, the water trap chamber is partially filled with water, into which one end of the air supply tube is immersed, the other end of which is brought out, this, the air intake element informs the internal volume of the anolyte separator chamber with the internal volume of the hydraulic lock chamber above the liquid level in them, and on the side walls of the housing, erimetru, reference marks to ensure the possibility of liquid level control in all three cameras simultaneously.

In the particular case of the implementation of the device, the air intake element can be made in the form of a through hole in the wall separating the chambers of the hydraulic lock and the anolyte separator.

The control marks applied around the perimeter of the housing are made in the form of two horizontal lines showing the maximum, maximum and minimum levels of fluid in the chambers of the separators and the seal. The presence of a liquid level in all three volumes between the mentioned lines indicates the normal operation of the installation.

Due to the fact that all three devices requiring attention and control by the operator are arranged in a single unit with a unified system of check marks, the efficiency of monitoring is increased and the process of responding to its results is accelerated: recognition of problems and their elimination. As a result, the risk of an emergency has decreased, the duration of uninterrupted operation of the installation has increased, and the reliability and safety of the station has increased.

The implementation of the control and separation device in the form of a single unit also allows to simplify maintenance and increase the productivity of installation work.

Thus, both objects of the claimed invention are aimed at solving the same technical problem and ensure the achievement of the same technical result: improving safety and operational reliability.

As a control device for metering pumps, it is preferable to use a controller that is a microprocessor device and is characterized by wide functionality. The controller is connected with devices for monitoring the level of chlorine in disinfected water and provides control over the operation of metering pumps, as well as the power supply unit of the electrolyzer, based on information received from the said control devices.

As metering pumps, it is preferable to use diaphragm metering pumps, which are highly resistant to corrosion in relation to an aggressive working medium - brine.

As the electrolyzer, it is preferable to use a membrane bipolar electrolyzer of a filter-press type consisting of several bipolar cells.

To ensure uninterrupted operation and expand the possibilities of chlorination, the station can be equipped with a second backup set of equipment connected in parallel with the first. The set of equipment includes an electrolyzer, metering pumps and separators with a water lock. The availability of a backup kit allows carrying out preventive or repair work on the main electrolyzer without stopping the operation of the plant as a whole, which is especially important at such large water disinfection stations as, for example, urban wastewater treatment plants.

However, the presence of a second electrolyzer allows, if necessary, to double the capacity of the installation, and hence the production of chlorine, for example. if necessary, the implementation of hyperchlorination.

It is advisable to install a water storage tank in the water supply line, which is placed at the inlet of the metering pump, which ensures the uninterrupted operation of the latter.

For the most complete use of the initial electrolyte solution, circulating circuits of anolyte and catholyte can be organized.

Brief Description of the Drawings

The design of the installation and the principle of its operation are illustrated by drawings, where

figure 1 - diagram of the station, a General view;

figure 2 - shows a diagram of a station with a backup set of equipment;

figure 3 - control device and separation, General view, isometry;

figure 4 is the same, view A, a top view from figure 3;

figure 5 is the same, section bb of figure 4, a longitudinal section;

figure 6 is the same, view C in figure 5, side view.

The implementation of the invention

The water disinfection station, which is based on an electrolysis plant for producing chlorine, contains (see Fig. 1) an electrolyzer 1 with a membrane partition 2 anode 3 and a cathode 4 separated by a chamber, a sodium chloride solution preparation unit, including a solution tank 5 with mixing means, connected to the input of the anode chamber 3 by a solution supply line 6 in which the metering pump 7 is installed. The input of the cathode chamber 4 of the electrolyzer 1 is connected to a water supply line 8 in which a storage tank for water 9 and a metering pump are installed 10. The station also contains a control and separation device 11, including anolyte separator 12, a water trap 13 and a catholyte separator 14, connected to the alkali storage 15. The gas outlet pipe of the anolyte separator 12 is connected to the suction pipe of the ejector 16 installed in the flow line 17. The control and separation device 11 may consist of separate devices, but it is preferable to design it as a single unit.

The operation of the station is as follows.

The prepared solution of sodium chloride from the tank 5 is supplied by the metering pump 7 to the input of the anode chamber 3 of the electrolyzer 1. Water is supplied by the metering pump 10 to the cathode chamber 4 of the electrolyzer 1.

When an electric current passes between the anode and cathode through a salt solution, chlorine gas is synthesized at the anode, and hydrogen is synthesized at the cathode. By reducing the density of the electrolyte as a result of gas filling, the mixture of anolyte with gaseous chlorine obtained as a result of electrolysis rises to the outlet of the anode chamber 3, from where it is removed to the anolyte separator 12, where it is separated into gaseous and liquid phases. The intensification of the separation process is facilitated by the flow of air into the separator 12 through the air intake pipe 18 and the water trap 13, which can be connected to the air supply line 19. When water passes through the ejector 16, a vacuum is formed, due to which the gaseous products separated in the separator 12 are sucked into the ejector 16 and miscible with water to form chlorine water.

The resulting chlorine water is then supplied to the points of introduction of the chlorinating agent, which can be located, for example, in special water treatment tanks at a particular water utility facility where the proposed installation is installed.

At the same time, a gas-liquid mixture formed in the cathode chamber 4 enters the catholyte separator 14, where it separates the gaseous phase - hydrogen, from the liquid catholyte phase, which is alkali, which, as it accumulates, is removed from the separator 14 through the corresponding nozzle into the storage tank 15. Hydrogen discharged into the atmosphere.

Because the anolyte moves from the entrance to the exit of the anode chamber and, similarly, catholyte in the cathode chamber, is fast enough, then the starting materials do not have time to completely react. For a more complete use of the initial electrolyte solution, circulating circuits of anolyte and catholyte can be organized. Why, the anolyte separator 12 is connected to the input of the anode chamber 3 by the anolyte return line 20, and the catholyte separator 14 is connected to the input of the cathode chamber 4 by the catholyte return line 21.

During the operation of the installation, there may be cases when the ejector 16 ceases to work due to any circumstances that have arisen, for example: the pressure of the inlet water has dropped or the pressure at the outlet of the ejector has increased, or the water has disappeared. Chlorine ceases to be sucked out from the anolyte separator 12, however, the electrolyzer 1 continues to work and chlorine gas is ejected back through the air inlet 18. Due to the fact that a water seal is installed at the inlet of the air inlet 18, the chlorine displaced into the chamber 13 enters the water, where it dissolves to form chlorine water. The latter is pushed further from the chamber 13 into the air intake pipe 22, where it forms a water plug, preventing the ingress of chlorine into the station room, which ensures the safety of the staff.

Dispensing pumps 7 and 10, which carry out the metered supply of saline and water to the electrolysis, are made with the possibility of external control, which is carried out by the controller 23, which simultaneously controls the power supply 24 of the electrolyzer 1. The controller 23 is connected with devices 25 for monitoring the level of chlorine in the disinfected water, and based on the information received from them, it regulates the operation of the power supply unit of the electrolyzer and metering pumps.

Figure 2 shows the design of the water disinfection station, equipped with a backup set of equipment, including a second electrolyzer 1 'with a control and separation device 11' and metering pumps 7 'and 10'.

Monitoring the operation of the electrolysis plant can be carried out by one operator. The simplicity and efficiency of control is facilitated by the execution of the control and separation device 11 in the form of a single unit uniting the anolyte separators, 14 catholyte separators 12 and a water seal 13, placed in one transparent case 26. Materials and methods used for the manufacture of known materials are used to manufacture the case and the device separators.

In a specific embodiment, the housing 26 is made (see FIGS. 3-6) in the form of a horizontally oriented rectangular parallelepiped formed by a bottom, a lid and plexiglass side walls hermetically connected to each other by means of a transparent adhesive connection. The housing 26 is divided by transverse partitions into three isolated volumes - chambers 27, 28 and 29, in which, respectively, anolyte separator, water trap and catholyte separator are placed.

The internal volumes of the chambers 27 and 28 (the anolyte separator and the water seal) are interconnected by means of an air intake pipe 18 'or by means of a through hole 18 "made in the wall separating the chambers 27 and 28 (see Figs. 4, 5).

On each of the side walls of the housing 26, control marks 30 are applied in the form of two horizontal red lines showing the minimum and maximum limit levels of fluid content in the chambers. The volumes of the cameras 27-29 are selected in such a way that the labels of the limit levels are the same for all three devices.

The control and separation unit 11, mounted above the electrolyzer 1, has good visibility, and the presence of control marks along the perimeter of the transparent case allows the operator from any side of the installation, wherever he is, to monitor the status of all three devices making up the unit.

Reducing or exceeding the liquid level of the limit red line 30 at least in one of the chambers 27, 28 and 29 is quickly recorded by the operator, while due to the fact that all controlled devices are concentrated in one place and at the same level, it is much easier for the operator to compare and understand them the cause of the malfunction. As a result, the causes of the malfunction are more quickly eliminated.

Claims (11)

1. A water disinfection station comprising an electrolyzer with an anode and cathode chambers separated by a membrane partition, a sodium chloride solution preparation unit and a water supply line connected with dosing means, an anolyte separator installed at the anode chamber outlet and provided with an air intake element installed at the cathode chamber outlet a catholyte separator associated with an alkali accumulator, and an ejector installed in the flow line, the suction pipe of which is connected to the outlet gas outlet pipe with anolyte separator, characterized in that it is equipped with a water trap installed at the inlet of the air intake element of the anolyte separator, while the metering devices are made in the form of metering pumps with external control, one of which is installed in the supply line of the sodium chloride solution at the input of the anode chamber, and the other - in the water supply line to the input of the cathode chamber. 2. The station according to claim 1, characterized in that the water seal is made in the form of a chamber partially filled with water with an air supply tube, one end of which is immersed in water and the other brought out, while the air intake element communicates the internal volume of the anolyte separator with the internal volume of the said chamber above the fluid level in them. 3. The station according to claim 1, characterized in that the anolyte separator, catholyte separator and water trap are combined into a single control and separation unit, located in one transparent case equipped with a single system of control marks. 4. The station according to claim 1, characterized in that the metering pump control device is implemented on the basis of a controller configured to control the power supply unit of the electrolyzer and connected with devices for monitoring the level of chlorine in the disinfected water. 5. The station according to claim 1, characterized in that the water supply line contains a storage tank installed at the inlet of the metering pump. 6. The station according to claim 1, characterized in that it is equipped with a second backup set of equipment connected in parallel with the first, including an electrolyzer, metering pumps and separators with a water seal. 7. The station according to claim 1, characterized in that as the metering pumps used diaphragm metering pumps. 8. The station according to claim 1, characterized in that it is equipped with a return line of the recovered anolyte from the anolyte separator to the input of the anode chamber and a return line of the recovered catholyte from the catholyte separator to the input of the cathode chamber. 9. A control and separation device intended for use in a water disinfection station, comprising a transparent casing, divided by partitions into three chambers, in which an anolyte separator equipped with an air intake element, a water trap and a catholyte separator are placed, the water trap chamber is partially filled with water into which one is immersed the end of the air supply tube, the other end of which is brought out, while the air intake element communicates the internal volume of the chamber of the anolyte separator with the internal volume of the chamber g drozatvora above the level of liquid in them, and on the side walls of the case, on the perimeter, reference marks to ensure the control of liquid level in all three cameras simultaneously. 10. The device according to claim 9, characterized in that the air intake element is made in the form of a through hole in the wall separating the chamber of the water seal and the anolyte separator. 11. The device according to claim 9, characterized in that the control marks are made in the form of two horizontal lines showing the maximum, maximum and minimum levels of fluid in the chambers.

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