Method and device for disinfecting water and water supply system comprising the device

Abstract

The invention relates to a method for disinfecting water in a water supply system by means of the production of active chlorine using an electrolysis device, which comprises an electrolysis cell, which is provided with electrodes, over which a voltage difference is applied. The invention also relates to an electrolysis device for disinfecting water in a water supply system by means of the production of active chlorine. The invention also relates to a water supply system comprising an electrolysis device.

Description

[0001] This invention relates to a method for disinfecting water in a water supply system by generating active chlorine using an electrolysis device, the electrolysis device comprising an electrolysis cell having electrodes on which a voltage difference is applied. The invention also relates to an electrolysis device for disinfecting water in a water supply system by generating active chlorine. Furthermore, the invention relates to a water supply system including the electrolysis device.

[0002] Electrolysis is a technique that uses direct current (DC) to drive other non-spontaneous chemical reactions. Electrolysis is known for its use in water disinfection. Typically, sodium chloride (NaCl) is electrochemically converted to produce chlorine. This salt forms Na+... + and Cl - It dissolves in water in the form of ions. When the solution is guided through an electrolytic cell, while a voltage is applied to the electrodes of the cell, chloride (Cl2), oxygen, and hydrogen ions are formed at the anode, and hydrogen and hydroxyl ions are formed at the cathode.

[0003] Depending on the pH, the chlorine formed at the anode can also present as hypochlorous acid (HClO) or hypochlorite (ClO). - Dissolved chlorine, hypochlorous acid, and hypochlorite are referred to as "free chlorine," "free active chlorine," or "active chlorine." Sodium hypochlorite will form when using (ordinary) tap water with a pH of approximately 7 to 8 and containing a small concentration of NaCl. The amount of free chlorine to be formed will depend on the desired concentration and the volume of water being treated.

[0004] An example of an electrolysis apparatus is disclosed in the inventor's EP 1461291 B1, which discloses, as follows: Figure 1The electrolysis apparatus shown is an electrolytic cell 6 with electrodes 14a and 14b. A voltage difference is applied to the electrodes 14a and 14b. The apparatus also includes a generator 1 installed in the main pipeline 4 to supply the voltage difference to the electrolytic cell. The generator includes an impeller 2 driven by water from the water supply system and a direct current (DC) generator 3. The device further includes a supply pipe 5 for the electrolytic cell, which is connected to a water supply system and directs a portion of the water flow from the water supply system to the electrolytic cell; a discharge pipe 7 for the electrolytic cell, which is connected to the water supply system downstream of the location where the supply pipe for the electrolytic cell is connected, and discharges the treated water in the electrolytic cell to the water supply system; a salt metering device 9 containing a compound capable of supplying chloride ions; a supply pipe 8 for the salt metering device, which is connected to the supply pipe 5 for the electrolytic cell and supplies at least a portion of the water in the supply pipe 5 for the electrolytic cell to the salt metering device 9 for supplying chloride ions to the water to be treated in the electrolytic cell 6; and a discharge pipe 10 for the salt metering device 9, which is connected downstream of the location where the supply pipe 8 for the salt metering device is connected to the supply pipe 5 for the electrolytic cell, and discharges the treated water in the electrolytic cell to the water to be treated. 10. A device for guiding chloride-containing water from salt metering device 9 to supply pipe 5 for electrolytic cell; and a device for regulating the ratio of water flow in the water supply system, feed to electrolytic cell and feed to salt metering device, the device including limiting valves and / or regulating valves (11, 12), the limiting valves and / or regulating valves (11, 12) being housed in the water supply system, between the location where supply pipe 5 for electrolytic cell is connected to the water supply system and the location where discharge pipe 7 for electrolytic cell is connected to the water supply system, in supply pipe 5 for electrolytic cell, in discharge pipe 7 for electrolytic cell, in supply pipe 8 for salt metering device and / or in discharge pipe 10 for salt metering device 9; and / or the impeller 2 of generator 1 being housed in the water supply system and located downstream of the location where supply pipe 5 for electrolytic cell is connected to the water supply system and upstream of the location where discharge pipe 7 for electrolytic cell is connected to the water supply system.

[0005] Although the electrolysis device of EP 1461291 B1 functions well, the inventors have found that there is still room for improvement, particularly regarding the regulation of energy input and the associated energy utilization efficiency. Summary of the Invention

[0006] In a first aspect, the present invention relates to a method for disinfecting water in a water supply system by means of generating active chlorine using an electrolysis device comprising an electrolysis cell provided with electrodes, applying a voltage difference across the electrodes, wherein the method comprises: providing a voltage difference to the electrolysis cell using an alternating current (AC) generator, wherein the AC generator uses water flowing through the water supply system to generate alternating current, the frequency of which is proportional to the flow rate of the water in the water supply system; and converting the generated AC into direct current (DC) using a converter to generate direct current and a voltage difference across the electrodes, wherein the converter is controlled to supply the voltage difference and direct current required for the electrolysis to generate active chlorine based on the AC frequency.

[0007] In a second aspect, the present invention relates to an electrolysis apparatus for disinfecting water in a water supply system by means of generating active chlorine, comprising: an electrolysis cell having electrodes capable of applying a voltage difference across the electrodes; an alternating current (AC) generator configured to generate alternating current using water flowing through the water supply system, the alternating current having an AC frequency proportional to the flow rate of the water in the water supply system; a converter configured to convert the generated AC current into direct current (DC) for applying a voltage difference across the electrodes of the electrolysis cell; and a control device configured to control the converter to supply DC based on the AC frequency for generating the voltage difference required for electrolysis to produce active chlorine.

[0008] In a third aspect, the present invention relates to a water supply system comprising an electrolysis device according to the second aspect.

[0009] The inventors have discovered that using an AC generator according to the invention allows the generation of electrical energy required for electrolysis, while the frequency of the AC generated by the generator can be used to control the energy input required for efficient generation of active chlorine. In other words, the amount of active chlorine generated within a given time is based on the AC frequency. Hereinafter, a specific AC frequency can be coupled to generate a specific, predetermined amount of active chlorine. In other words, a predetermined amount of active chlorine can be generated within a given time based on a predetermined AC frequency. Accordingly, the electrolytic cell can be configured to generate a predetermined amount of active chlorine within a given time based on a predetermined AC frequency (using the input of a control device). Hereinafter, the predetermined determination of the specific amount of chlorine to be generated aims to define the amount of chlorine required to purify a given initial quality of water to a desired quality within a given time, which is consistent with the flow rate of water in the water supply system.

[0010] This is because the AC generator is driven by the flow of water in the water supply system, for example, by using an impeller driven by water in the water supply system, such that the AC frequency is proportional to the flow rate of the water in the water supply system. Therefore, the AC frequency can be used as a measure of the amount of water that needs to be disinfected in an electrolytic cell (e.g., a membrane electrolyzer). The amount of water passing through the electrolytic cell within a given time period is thus proportional to the amount of chlorine required for disinfection. Furthermore, the amount of chlorine produced within a given time depends on the voltage difference between the electrodes and the current flowing between the electrodes. In other words, the more chlorine needs to be produced within a given time, the higher the voltage difference between the electrodes and the current flowing between the electrodes should be. Given this proportional relationship between these parameters, the inventors have recognized that the AC frequency can be used according to the invention as a measure of the energy input required to control the effective production of active chlorine, wherein a given frequency can be attributed to the required voltage difference between the electrodes and the current flowing between the electrodes. This is efficient for energy use, but the present invention also provides a very reliable and efficient method for controlling the amount of chlorine to be produced, because providing energy for electrolysis and its regulation are physically related to each other, as both require an AC generator as a key component.

[0011] This invention is highly useful for purifying tap water or water of equivalent quality, or in other words, water of relatively good quality. In this regard, it is preferred that, in the context of this invention, the water supply system is configured to supply tap water or water of equivalent quality. Herein, the amount of salt required in the electrolytic cell, as well as the voltage and current required for treatment at a given water flow rate and desired chlorine content, can be effectively controlled based on these parameters, thus making this invention a simple and effective system for purifying water.

[0012] Further concerning the AC generator, in a preferred embodiment, the AC generator is housed in the water supply system, downstream of where the supply pipe for the electrolytic cell connects to the water supply system and upstream of where the discharge pipe for the electrolytic cell connects to the water supply system; that is, the electrolytic cell is then located in a bypass of the main pipeline. Due to this positioning of the AC generator, a slight pressure drop will occur at the generator, resulting in the possibility of generating a flow of water that will travel through the electrolytic cell. Nevertheless, it is possible to house the generator elsewhere in the water supply system. However, measures would then have to be taken, for example, by providing a limiting valve or regulating valve in the main pipeline, to ensure sufficient flow through the electrolytic cell.

[0013] Any electrolytic reaction requires a supply of electrical energy, which means both voltage and current are needed. In practice, a slightly higher voltage is required because the enthalpy (heating) of the products leads to slightly lower efficiency, manifested as overpotential. For the production of active chlorine as in this invention, a basic voltage difference is required to initiate the electrolytic process. Depending on the electrode material, this can be, for example, about 0.8 V. Once this critical voltage level is exceeded, the electrolytic reaction follows Ohm's law and proceeds at a rate primarily determined by the current. Basically, the higher the current, the more molecules react (electrolyze) per unit time, and the more products (active chlorine) are formed. Given this, it should be understood that the relationship between the required voltage difference and the current in the electrolytic cell is not always linear.

[0014] Therefore, it is preferable to calibrate the electrolysis apparatus such that the control converter supplies DC based on the AC frequency to generate the voltage difference required for electrolysis to produce active chlorine. This includes pre-determining the correlation between the flow rate and the corresponding generated AC frequency; and pre-determining the correlation between the AC frequency and the corresponding DC current and voltage difference required for electrolysis to produce active chlorine; and using these correlations to control the converter such that the voltage difference and DC current required for electrolysis to produce active chlorine are applied in the electrolytic cell.

[0015] In a given water supply system, the situation is relatively stable. That is, the same equipment, piping system, valves, and electrolytic cells are used for a longer period of time. Therefore, the required voltage and current in the electrolytic cell can be controlled in a relatively simple manner by a controller with a pre-programmed device. In view of this, it is preferable in the apparatus of the present invention to program the control device to control the converter using a predetermined correlation between the AC frequency generated by the AC generator and the corresponding DC and / or voltage difference required for the electrolysis to produce active chlorine, such that the voltage difference required for the electrolysis to produce active chlorine is applied to the electrodes. Since the apparatus and method of the present invention can generally be used for a longer period of time in the same water supply system, this can be suitably achieved by pre-programming the controller, using desired parameters (such as AC frequency and desired DC current and voltage), and optionally by calibrating the controller to a specific AC generator and electrolytic cell using the flow rate of the water supply system. When the controller detects a certain AC frequency, it can respond by causing the converter to generate a certain DC current, which is in turn linked to a certain voltage to be established on the electrodes, which can be achieved via the same controller or a separate controller.

[0016] Although conditions in a given water supply system are relatively stable, deviations or undesirable events may occasionally occur. For example, in the case of suboptimal salt concentrations, the voltage difference across the electrodes may be much higher than expected based on a predetermined correlation, because the conductivity in the electrolytic cell is too low due to an excessive amount of salt ions. Furthermore, defects may occur in the generator, resulting in voltages that are too low on the electrodes. In view of such potential undesirable events, the method according to the invention may include an alarm system. For this purpose, the actual voltage difference across the electrodes can be determined, and whether the actual voltage difference matches the expected voltage difference can be monitored based on a predetermined correlation between the AC frequency and the corresponding DC voltage difference. An alarm signal can then be generated when the actual voltage difference does not match the voltage difference expected based on the predetermined correlation. Such a system can be implemented in an apparatus according to the invention, comprising: a voltmeter configured to determine an actual voltage difference across electrodes; a monitoring device configured to monitor whether the actual voltage difference matches an expected voltage difference based on a predetermined correlation between an AC frequency and a corresponding DC voltage difference; and an alarm device configured to generate an alarm signal based on an input from the monitoring device when the actual voltage difference does not match the expected voltage difference. The alarm system may, for example, include an LED indicator configured to generate an alarm signal.

[0017] The electronic circuitry is preferably implemented on one or more printed circuit boards (PCBs). For example, the controller and control device may be included on the PCB, optionally with additional components. The use of a PCB allows for compact design. Depending on specific needs, the device according to the invention may be equipped with suitable circuitry, sensors, etc., based on common knowledge in the field of electronics. The PCB may contain a device for collecting and storing information about water flow, the amount of water being treated, current, voltage, salt concentration, and conversion, which can be remotely monitored using a wireless connection.

[0018] Any additional equipment can be used to design the device according to the invention according to the user's wishes, such as pipe systems, piping systems, valves, salt storage and / or salt metering devices, etc.

[0019] In an exemplary embodiment, the device may be designed to include an AC generator in the main pipeline for supplying a voltage differential to the electrolytic cell. This AC generator includes an impeller driven by water from the water supply system. Such a generator is commonly referred to as a turbine generator. In a turbine generator, flowing water drives a series of blades mounted on a rotor shaft. The force of the water acting on the blades causes the generator's rotor shaft to rotate rapidly. The generator then converts the mechanical (dynamic) energy of the rotor into electrical energy.

[0020] According to the invention, an (AC) generator is configured to use water flowing through a water supply system to generate AC, the AC having an AC frequency proportional to the flow rate of the water in the water supply system. The device also includes a converter and a control device, the converter being configured to convert the generated AC into direct current (DC) to apply voltage to the electrodes of an electrolytic cell, and the control device being configured to control the converter to supply DC based on the AC frequency for generating the voltage difference required for the electrolysis to produce active chlorine. The device may further include a supply pipe for the electrolytic cell and a discharge pipe for the electrolytic cell, the supply pipe for the electrolytic cell being connected to the water supply system and directing a portion of the water flow from the water supply system to the electrolytic cell, and the discharge pipe for the electrolytic cell being connected downstream of the location where the supply pipe for the electrolytic cell connects to the water supply system and discharging the treated water in the electrolytic cell into the water supply system. The apparatus may further include: a salt metering device containing a compound capable of supplying chloride ions; a supply pipe for the salt metering device, connected to a supply pipe for the electrolytic cell, and supplying at least a portion of the water in the supply pipe for the electrolytic cell to the salt metering device to supply chloride ions to the water to be treated in the electrolytic cell; and a discharge pipe for the salt metering device, connected downstream of the supply pipe for the salt metering device to the supply pipe for the electrolytic cell, and guiding chloride-containing water from the salt metering device to the supply pipe for the electrolytic cell. The device may also include equipment for regulating the ratio of water flow in the water supply system, feed to the electrolytic cell, and feed to the salt metering device. This equipment may include a limiting valve and / or a regulating valve, which are housed in the water supply system between the location where the supply pipe for the electrolytic cell is connected to the water supply system and the location where the discharge pipe for the electrolytic cell is connected to the water supply system, in the supply pipe for the electrolytic cell, in the discharge pipe for the electrolytic cell, in the supply pipe for the salt metering device, and / or in the discharge pipe for the salt metering device, and / or the generator impeller is housed in the water supply system downstream of the location where the supply pipe for the electrolytic cell is connected to the water supply system and upstream of the location where the discharge pipe for the electrolytic cell is connected to the water supply system.

[0021] This invention is particularly suitable for disinfecting water in water supply systems that transport water that has not been heated to a sufficient temperature. A particular risk of such systems is the formation of Legionella bacteria. Legionella is a bacterium that can cause airway infections known as Legionella or Legionnaires' disease. Legionella grows in water at temperatures between 20 and 50 degrees Celsius and in stagnant water. Heat pump-based heating systems (which have recently gained more interest due to the ongoing energy shift) operate within these temperature ranges to heat water, but typically do not heat the water above these temperatures. Therefore, heat pump-based heating systems generally do not provide sufficient heat to prevent Legionella growth. This invention allows for the disinfection of water in water supply systems involving heat pump-based heating without requiring additional external energy input. In this respect, the method according to the invention is particularly suitable for preventing Legionella growth in water supply systems where the maximum water temperature is insufficient, such as water supply systems including heat pump-based heating systems. In view of this, the invention also relates to a water supply system comprising an electrolysis device according to the invention, preferably comprising a heat pump-based heating system. Compared to other disinfection methods, such as heat treatment using a boiler, buffer tanks with heat enhancers, or exposing water to UV-C light, the implementation of this invention in a water supply system including a heat pump-based heating system saves considerable energy and cost. Attached Figure Description

[0022] Figure 1 An existing electrolysis apparatus is shown schematically.

[0023] Figure 2 An electrolysis apparatus according to a preferred embodiment of the present invention is illustrated schematically. Detailed Implementation

[0024] The following exemplary embodiments are intended to illustrate the invention and do not limit the scope of the claims.

[0025] In the attached Figure 2 The image schematically illustrates an electrolysis apparatus according to a preferred embodiment of the present invention. Figure 2The diagram shows an AC generator 101 comprising an AC generator dynamo 103, an impeller 102, and a PCB 113. The impeller 102 is positioned within a main pipe 104 to allow flowing water to drive the generator 103. A supply pipe 105 for the electrolyzer 106 branches off from the main pipe 104 upstream of the AC generator 101 and directs a portion of the water to the electrolyzer 106. The AC generator 103 uses the water flowing through the main pipe 104 to generate AC, the AC frequency being proportional to the flow rate of the water in the supply system using the impeller 102. The PCB 113 uses a converter implemented on the PCB 113 to convert the generated AC into direct current (DC) for applying voltage to electrodes 116a, 116b of the electrolyzer 106. The converter is controlled to supply DC based on the AC frequency to generate the voltage difference required for electrolysis to produce active chlorine. A discharge pipe 107 for the electrolyzer 106 directs the treated water from the electrolyzer 106 back to the main pipe 104. exist Figure 2 The device also includes a salt metering device 109. A branch of the supply pipe 108 for the salt metering device 109 flows through the supply pipe 105 for the electrolytic cell 106 and is directed to the salt metering device 109, where a saturated sodium chloride solution and solid sodium chloride are present, and where salt is absorbed in the water. The discharge pipe 110 for the salt metering device 109 directs the aqueous salt back to the supply pipe 105 for the electrolytic cell 106. Numbers 111 and 112 refer to the check valve and the limiting section, respectively. When the generator 101 is not operating adequately, or when there is no or insufficient salt supplied to the water, the current in electrodes 116a and 116b will drop sharply and the voltage will increase. This can be detected by detector 114, which then sends a signal to PCB 113, which can, for example, actuate an alarm light 115 on the system.

[0026] For use with 10 cm 2 An exemplary electrolytic cell 106 with electrodes on the surface can be programmed to a controller in a PCB to deliver the current and voltage required to produce 0.3 mg / L of active chlorine using correlations based on the values ​​shown in the table.

Claims

1. A method for disinfecting water in a water supply system by means of generating active chlorine using an electrolysis device, said electrolysis device comprising an electrolysis cell provided with electrodes, wherein a voltage difference is applied across the electrodes, wherein, The method includes: The electrolytic cell is supplied with the voltage difference using an alternating current (AC) generator, wherein the AC generator uses water flowing through the water supply system to generate AC power, the AC power having an AC frequency proportional to the flow rate of the water in the water supply system; and The generated alternating current is converted into direct current (DC) using a converter to generate DC and the voltage difference on the electrodes, wherein the converter is controlled to supply the voltage difference and DC required for electrolysis to generate active chlorine based on the AC frequency; The control of the converter to supply direct current based on the alternating current frequency for generating the voltage difference required for electrolysis to produce active chlorine includes: The correlation between the flow rate and the corresponding AC frequency is determined in advance; The correlation between the AC frequency and the corresponding DC current and voltage difference required for the electrolysis to generate active chlorine is determined in advance; and These correlations are used to control the converter so that the voltage difference and direct current required for electrolysis to produce active chlorine are applied in the electrolytic cell.

2. The method according to claim 1, further comprising: The actual voltage difference on the electrode is determined, and the actual voltage difference is monitored to ensure it matches the expected voltage difference based on a predetermined correlation between the AC frequency and the corresponding DC voltage and voltage difference. An alarm signal is generated when the actual voltage difference does not match the expected voltage difference.

3. The method according to claim 1, wherein, The water supply system includes a heat pump-based heating system.

4. The method according to any one of claims 1 to 3, wherein, The water supply system is configured to supply tap water.

5. An electrolytic device for disinfecting water in a water supply system by generating active chlorine, comprising: An electrolytic cell, wherein the electrolytic cell is provided with electrodes, and a voltage difference can be applied to the electrodes; An alternating current (AC) generator configured to generate alternating current using water flowing through the water supply system, the alternating current having an AC frequency proportional to the flow rate of the water in the water supply system. A converter configured to convert the generated alternating current into direct current (DC) for applying the voltage difference to the electrodes of the electrolytic cell; as well as A control device configured to control the converter to supply the DC based on the AC frequency for generating the voltage difference required for electrolysis to produce active chlorine; The control device is programmed as follows: The converter is controlled using a predetermined correlation between the AC frequency generated by the AC generator and the corresponding DC current and voltage difference required for the electrolysis to produce active chlorine, such that the voltage difference required for the electrolysis to produce active chlorine is applied to the electrodes.

6. The electrolysis apparatus according to claim 5, wherein, The converter and the control device are included in a printed circuit board (PCB).

7. The electrolysis apparatus according to claim 5, wherein, The AC generator includes an impeller driven by water from the water supply system.

8. The electrolysis apparatus according to claim 5, further comprising: A voltmeter configured to determine the actual voltage difference across the electrodes; A monitoring device is used to monitor whether the actual voltage difference is consistent with the expected voltage difference based on a predetermined correlation between the AC frequency and the corresponding DC voltage and voltage difference. as well as An alarm device configured to generate an alarm signal based on input from the monitoring device when the actual voltage difference is inconsistent with the expected voltage difference.

9. The electrolysis apparatus according to claim 8, wherein, The alarm device includes an LED indicator configured to generate an alarm signal.

10. The electrolysis apparatus according to claim 5, wherein, The water supply system is configured to supply tap water.

11. A water supply system comprising an electrolysis device according to any one of claims 5 to 10.

12. The water supply system according to claim 11, wherein the water supply system includes a heat pump-based heating system.

13. The water supply system according to claim 11, wherein, The water supply system is configured to supply tap water.

14. The use of an electrolysis apparatus according to any one of claims 5 to 9 for preventing Legionella in a water supply system with a water temperature between 20°C and 50°C.

Images