Device for treating circulating water of power plant through electrochemical pretreatment-electrolysis coupling

Abstract

The utility model provides a device for treating circulating water of a power plant through electrochemical pretreatment-electrolysis coupling, and belongs to the field of electrochemical treatment of wastewater. Comprising a raw water tank, a simulated cooling tower, a sand filter tower, an electrochemical scale inhibition device, an oxidation polarization device, a buffer tank, an electric carbon filter device, an electric adsorption device and an electrolytic sterilization device which are connected in sequence. Ions in the circulating water of the power plant are separated and concentrated through electrochemical pretreatment, part of pretreated wastewater is reused for a circulating water system, and a generated oxidizing agent can be used for disinfection and sterilization of the circulating water. According to the utility model, the circulating water can be partially recycled, the discharge of the circulating water is reduced, and the output of the recycled water and the oxidizing agent can be dynamically regulated according to the quality and quantity of the circulating water, so that the dynamic balance of the water resource utilization of the circulating water system is achieved, and the oxidizing agent can be produced without any additional chemical agent and reused for the disinfection and sterilization of the circulating water.

Description

Technical Field

[0001] The utility model relates to the technical field of water treatment, in particular to a device for treating circulating water of a power plant by electrochemical pretreatment-electrolysis coupling. Background Art

[0002] The primary function of circulating cooling water in thermal power plants is to transfer and dissipate heat, ensuring the proper operation of the generator sets. During this process, the circulating cooling water absorbs heat exhausted by the turbines, carries this heat to the cooling tower, and then releases the heat into the atmosphere through evaporation and air convection, thereby maintaining the normal operating temperature of the units. The main components of circulating cooling water include water, dissolved oxygen, nitrogen and phosphorus salts, and calcium and magnesium hardness. Because circulating water systems are suitable for bacterial growth, they are prone to producing large amounts of biosludge. Furthermore, as the water evaporates, the salt content in the circulating water gradually increases, which can increase the tendency for scaling on heat transfer surfaces.

[0003] Improving the concentration rate of circulating cooling water and reusing wastewater are the keys to achieving water conservation and emission reduction, which requires the use of efficient treatment methods and technologies.

[0004] The principle of electrochemical scale inhibition is to form a low-voltage electric field between the cathode and the anode by applying a DC voltage, causing the positive and negative ions in the water to migrate to the plates of opposite polarity and gain or lose electrons, thereby preventing the formation of scale. In this process, a reduction reaction occurs on the cathode surface, producing hydroxide ions (OH - ), which forms an alkaline area near the cathode, thereby promoting the formation of carbonate (CO3 2- ) is generated. Scaling ions in circulating water such as calcium (Ca 2+ ), magnesium (Mg 2+ ) will be attracted to the cathode and react with carbonate (CO3 2- ), hydroxide (OH - ) reaction generates a precipitate that settles on the cathode surface of the electrolytic cell, reducing the concentration of scale-forming ions in the water and mitigating scaling. Furthermore, the high acidity of the anode reduces (or even eliminates) the alkalinity of the water, transforming the treated water into a high-hardness, low-alkalinity state, thereby achieving scale inhibition. Furthermore, since no additional chemicals are added, this technology is relatively environmentally friendly, reducing the level of contamination in discharged wastewater.

[0005] The principle of electrosorption wastewater concentration is to utilize charged electrode surfaces to adsorb ions in water, forming an electrical double layer that concentrates and enriches substances in the water on the electrode surface. This method is highly efficient and energy-efficient. It involves two main processes: adsorption and desorption. During the adsorption process, as the water to be treated passes through the porous electrodes, the electric field applied by the system influences the distribution of ions in the water. Under the influence of Coulomb forces, the interface between the electrode and the solution is occupied by ions with opposite charges (counterions), forming a dense electrical double layer. During this process, anions and cations in the solution gradually migrate to the oppositely charged electrode plates and are adsorbed on the material surface, thereby removing and concentrating ions in the water. During the desorption process, as the reaction proceeds, when the electrode surface reaches saturation with ions, the adsorbent material needs to be regenerated, or desorbed. This is typically accomplished by removing the electric field or reversing the power supply, allowing the ions adsorbed on the electrode to return to the solution and restore the electrode's adsorption capacity.

[0006] Electrolysis is a relatively mature water treatment technology. Essentially, it involves passing an electric current through an electrolyte solution, inducing redox reactions at the cathode and anode. This process can be categorized into direct oxidation, where pollutants are directly oxidized and decomposed at the anode, and indirect oxidation, where a strong oxidizing substance is first generated at the anode, which then oxidizes the pollutants. In recent years, electrolysis has been widely used in treating printing and dyeing wastewater, pharmaceutical wastewater, and organic wastewater.

[0007] The application of electrolytic chlorine production technology in the treatment of circulating cooling water in power plants is in the development stage. It has good application prospects. It is currently mainly used to solve problems such as microbial reproduction, scaling and corrosion, and provides an environmentally friendly and economical treatment solution for circulating wastewater in power plants. At present, the application of electrolytic chlorine production technology in the treatment of wastewater at the end of power plants is still relatively small, and it is mainly concentrated in the treatment of high-salt wastewater. Its technical route focuses on using a variety of membrane technologies or evaporation crystallization technologies to obtain high-purity sodium chloride solutions and then electrolyze chlorine. This study uses electrochemical technology to pre-treat the circulating water, eliminating the problems of membrane pollution, high energy consumption, high system complexity, etc. that may exist in membrane technology or evaporation crystallization technology. Part of the circulating wastewater is reused and part is electrolyzed to produce chlorine, which is expected to achieve zero discharge of circulating water.

[0008] In response to the several electrochemical technologies described above, attempts have been made in the prior art to couple one or more electrochemical technologies to treat industrial wastewater. Chinese Patent 202021365354.3 discloses an electrochemical system that couples a filtration tank, electrosorption, and electrolysis. The system can remove nitrobenzene, phenols, heavy metals, and ammonia nitrogen impurities in sewage. Through the adsorption and desorption process of positive and negative electrodes, the wastewater is highly purified. However, the electrodes use active metal electrodes and need to be replaced from time to time to avoid a decrease in work efficiency caused by anode corrosion; Chinese Patent 201510094785.8 discloses an electrochemical coupling system that combines the characteristics of electrosorption desalination and electrochemical oxidation. It makes full use of the anode and cathode, and has high removal efficiency for salts and difficult-to-degrade organic matter, but requires continuous introduction of oxygen-containing gas and the addition of optional Fe 2+ or Fe 3+ ions, consumes a lot of energy, and can only treat salt-containing organic wastewater. At the same time, when NaCl is used as the electrolyte, toxic chlorinated intermediates are easily produced during the electrolysis process. Summary of the Invention

[0009] The utility model provides a device for treating circulating water of a power plant by coupling electrochemical pretreatment and electrolysis, which solves the problems of excessive calcium and magnesium hardness in circulating sewage and wastewater reuse.

[0010] Compared with the existing technology, the utility model is formed by coupling electrochemical scale inhibition + oxidation polarization + electric adsorption + electrolytic sterilization devices. The electrodes used in the entire electrochemical coupling system are non-metallic electrodes, which are resistant to acid and alkali and not easily corroded. No reagents need to be added in the whole process, and no other ions will be introduced. The electric adsorption and electrolytic sterilization devices can realize the removal and resource utilization of chloride ions, and oxidize them into chlorine-based oxidants.

[0011] The utility model is based on the electrolysis method for treating desulfurization wastewater, and couples pretreatment processes such as scale resistance, electro-oxidation polarization, electro-filtration, and electro-adsorption. Calcium and magnesium hardness are precipitated on the plate through the scale resistance device and removed regularly. Through the electro-oxidation polarization technology, the carbonate hardness of the circulating water is maintained at 7mmol / L, and the corrosion inhibitor and the circulating water are kept between 7mmol / L and 7mmol / L, without adding scale inhibitors and corrosion inhibitors, and without scaling and corrosion of the circulating water. The sewage is deeply filtered through the electro-filtration device to remove impurities and suspended solids. The sewage is concentrated through the electro-adsorption device to enrich the chloride ions therein for the next electrolysis. The electrolysis device generates a high-concentration chlorine-based oxidant for self-disinfection and sterilization of the circulating water.

[0012] The beneficial effects of the utility model are: the circulating water can be partially recycled and utilized, the discharge of circulating water can be reduced, and the production of recycled water and oxidant can be dynamically regulated according to the water quality and quantity of the circulating water, so as to achieve a dynamic balance in the utilization of water resources in the circulating water system. Oxidants can be produced and reused for the disinfection and sterilization of circulating water without any additional chemical agents.

[0013] The specific technical solutions are:

[0014] An electrochemical pretreatment-electrolysis coupled treatment device for power plant circulating water includes a raw water tank, a simulated cooling tower, a sand filter tower, an electrochemical scale inhibition device, an oxidation polarization device, a buffer tank, an electro-carbon filtration device, an electro-adsorption device, and an electrolytic sterilization device connected in sequence;

[0015] The circulating water enters the simulated cooling tower from the raw water tank through the lifting pump for circulating water concentration. The concentrated circulating cooling water enters the sand filter tower for filtration. The filtered water enters the electrochemical scale inhibition device to reduce the temporary hardness in the electrochemical scale inhibition device; the water flowing out of the electrochemical scale inhibition device enters the oxidation polarization device. In the oxidation polarization device, the water molecules have polarity under the action of high-voltage static electricity, which plays a role in corrosion inhibition and corrosion prevention. The oxidation polarization effluent enters the buffer box, and the buffer box enters the electro-carbon filtration device to remove some suspended matter in the electro-carbon filtration device. The effluent of the electro-carbon filtration device enters the electro-adsorption device to remove permanent hardness ions and chloride ions in the electro-adsorption device; the electro-adsorption effluent of the electro-adsorption device enters the desulfurization system or the replenishment water of the circulating water, and the electro-adsorption desorption concentrated water of the electro-adsorption device enters the electrolytic sterilization device. In the electrolytic sterilization device, the chloride ions are oxidized to produce the oxidant hypochlorous acid. The electrolytic sterilization effluent of the electrolytic sterilization device is used as a bactericide and returned to the front of the desulfurization system triplex box.

[0016] Correspondingly, the method of the present utility model is:

[0017] The circulating water enters the simulated cooling tower from the raw water tank through the lifting pump for circulating water concentration. The concentrated circulating cooling water enters the sand filter tower for filtration. The filtered water enters the electrochemical scale inhibition device to reduce the temporary hardness in the electrochemical scale inhibition device; the water flowing out of the electrochemical scale inhibition device enters the oxidation polarization device. In the oxidation polarization device, the water molecules have polarity under the action of high-voltage static electricity, which plays a role in corrosion inhibition and corrosion prevention. The oxidation polarization effluent enters the buffer box, and the buffer box enters the electro-carbon filtration device to remove some suspended matter in the electro-carbon filtration device. The effluent of the electro-carbon filtration device enters the electro-adsorption device to remove permanent hardness ions and chloride ions in the electro-adsorption device; the electro-adsorption effluent of the electro-adsorption device enters the desulfurization system or the replenishment water of the circulating water, and the electro-adsorption desorption concentrated water of the electro-adsorption device enters the electrolytic sterilization device. In the electrolytic sterilization device, the chloride ions are oxidized to produce the oxidant hypochlorous acid. The electrolytic sterilization effluent of the electrolytic sterilization device is used as a bactericide and returned to the front of the desulfurization system triplex box.

[0018] The working principle of this utility model:

[0019] This utility model utilizes several different electrochemical technologies to couple and treat circulating cooling water. The electrochemical scale inhibition device primarily removes temporary hardness, while the electrosorption removes permanent hardness. Desorbed concentrated water is passed through an electrolysis device, utilizing the large amount of chloride ions present in the desorbed concentrated water as the core reactant to remove ammonia nitrogen and COD from the wastewater, while also recycling chloride ions and some wastewater. The main reactions are as follows:

[0020] 1. Electrochemical scale inhibition device: (outlet water is acidic)

[0021] Under the action of the electric field, anions migrate to the anode and cations migrate to the cathode.

[0022] (1) Cathode region:

[0023] Due to the electrolysis of water at the cathode, OH - , the pH of the cathode area is alkaline, and HCO3 near the cathode - and OH - Combined with:

[0024]

[0025]

[0026] Calcium and magnesium ions combine with calcium carbonate and hydroxide to form a precipitate:

[0027]

[0028] (2) Anode area (possible reaction):

[0029]

[0030] (3) Free chlorine:

[0031]

[0032] (4) Chlorine:

[0033]

[0034] (5) Hypochlorous acid:

[0035]

[0036] (6) Ozone:

[0037]

[0038] (7) Hydrogen peroxide:

[0039]

[0040] 2. Oxidation polarization device:

[0041] When circulating water flows through the high-voltage electrostatic field formed by the positive and negative electrodes, the water molecules carry positive and negative charges and develop polarity. The positively charged water molecule clusters first come into contact with the water container wall, acting as the cathode, blocking and enveloping anions, especially chloride ions, from direct contact with the container wall, thus providing cathodic protection. Simultaneously, the oxide film continuously formed on the cathode wall by oxygen polarization acts as a corrosion inhibitor against the water system wall in the alternating attack and defense process of chloride ions continuously penetrating the oxide film and causing pitting corrosion. Furthermore, the negatively charged water molecule clusters envelop cations such as calcium and magnesium from direct contact with the container wall, thus providing cathodic protection and scale inhibition.

[0042] 3. Electric adsorption device

[0043] When the oxidized polarized water is introduced into a low-voltage electric field composed of positive and negative electrodes, a double electric layer will be formed between the positive and negative electrodes. Calcium and magnesium ions will migrate toward the cathode and be adsorbed on the cathode, and chloride ions will be adsorbed on the anode. The permanent hardness and chloride ions in the flowing water will be significantly reduced, thereby achieving the purpose of salt reduction.

[0044] 4. Electrolytic sterilization device

[0045] Main reactions:

[0046] (1) The main reactions occurring in the cathode chamber:

[0047]

[0048] (2) The main reactions occurring in the anode chamber:

[0049]

[0050] (3) Overall reaction of direct oxidation of ammonia nitrogen:

[0051]

[0052] (4) Overall reaction of indirect oxidation of ammonia nitrogen:

[0053]

[0054] (5) In direct oxidation reaction, there is direct oxidation (acidic):

[0055]

[0056] Direct oxidation (alkaline):

[0057]

[0058] (6) Indirect oxidation can be divided into the following steps:

[0059]

[0060] During the selective migration of chloride ions, the selectivity coefficient of the membrane for low-valent and high-valent ions should be maintained at less than 0.35. The selectivity coefficient is calculated by the following formula:

[0061]

[0062] Where, is the permeability selectivity of ions A relative to ions B; 、 are the concentrations of ions A and B at time t, respectively; 、 are the initial concentrations of A and B ions, respectively.

[0063] Preferably, the pH of the wastewater before treatment in the electrochemical scale inhibition device should be maintained between 7.0 and 8.0. A low influent pH is not conducive to the electrochemical scale inhibition device removing temporary hardness ions.

[0064] Preferably, the electrochemical scale inhibition device adopts a non-metallic anode, which has strong resistance to oxidation, acid corrosion, and chloride ion corrosion, promotes a strong cathode reduction reaction and fast scale collection, and is conducive to the regeneration of the anode passivation film.

[0065] Preferably, the descaling method of the electrochemical scale inhibition device is the reverse pole method, which automatically descales. The non-metallic anode is regularly switched and regenerated in an acidic or alkaline environment, which is not likely to cause electrode deactivation or poisoning and does not affect the treatment efficiency.

[0066] Preferably, the working voltage of the electrochemical scale inhibition device should be set at 3~4V, and the current should be between 15~16A. Voltage is one of the key factors to maintain a high hardness removal rate of the electrochemical scale inhibition device. Lower voltage will reduce the removal efficiency, and higher voltage will increase energy consumption.

[0067] As a preferred option, the high-voltage static electricity generated by the oxidation polarization device is required to reach about 21,000V. The scale inhibition, corrosion prevention, and scale removal functions are used to maintain the circulating water in a high concentration ratio and high alkalinity environment without adding acid, providing complementary and guarantee for electrochemical improvement of scale removal efficiency and safe operation of the system, which can be called a bottom-up technology.

[0068] Preferably, the electrosorption voltage of the electrosorption device should be set at 1.2-2.5V, and the current should be between 4-5A. When the voltage is lower than 1.2V, ions cannot migrate to the electrode plates with opposite charges. When the voltage is higher than 2.5V, water electrolysis will occur, which will increase energy consumption and cause scale formation.

[0069] Preferably, the pH of the wastewater before treatment in the electrolytic sterilization device should be maintained between 4.0 and 6.0. A lower wastewater pH is more conducive to the occurrence of chlorine evolution reaction, and pH is an important control parameter for the conversion direction of ammonia nitrogen oxidation products. Under acidic conditions, ammonia nitrogen is more likely to be oxidized to produce nitrogen gas rather than nitrate ions. Nitrogen gas is non-toxic and harmless and can be directly discharged into the air, while nitrate ions, as a toxic substance, are not suitable as a treatment product.

[0070] Preferably, the anode is a titanium-based ruthenium-iridium coated electrode, which has a lower chlorine evolution potential and a higher oxygen evolution potential, and can enable the anode to produce more chlorine-based oxidants rather than oxygen, thereby reducing power consumption and being corrosion-resistant.

[0071] As a preference, the current density should be maintained at 20~30mA / cm 2 Current density is an important indicator of the effective utilization of reaction current. Lower current density means reduced energy consumption, but may lead to problems such as insufficient oxidation capacity and increased processing time. Higher current density means increased energy consumption, which may lead to decreased membrane selectivity, but also increases the driving force of ions across the membrane, increasing the intensity of the electrolytic reaction and reducing the reaction time.

[0072] Preferably, the electrolysis voltage should be maintained at around 3.0 to 4.0. Too high a voltage will lead to a loss of membrane selectivity, while too low a voltage will greatly increase the reaction time.

[0073] Preferably, the ORP value in the anode chamber should be controlled below 820 mV. The ORP value has three phases throughout the electrodialysis-electrolysis process: a first, rapid rise phase (-140 mV to 820 mV), a second, stable phase (≈820 mV), and a third, slow rise phase (>820 mV). When the ORP value is below 820 mV, the conversion of ammonia nitrogen to chloramine occurs. This process is the rate-determining step in the oxidation of ammonia nitrogen to nitrogen gas. Appropriately increasing the current density can help reduce the duration of this step. At an ORP value of approximately 820 mV, further oxidation and hydrolysis of chloramine occur. This process is largely unaffected by current density and lasts approximately 20 minutes. Above 820 mV, the electrolytic chlorine production reaction primarily occurs. Due to oxidant saturation, a large amount of chlorine oxidant is wasted in the air. Therefore, controlling the ORP value below 820 mV effectively determines the reaction endpoint and reduces energy waste.

[0074] The beneficial effects of the present invention are embodied in the following aspects:

[0075] (1) The process flow of circulating wastewater treatment is simplified, eliminating the need for additional chemical reagents, thus saving reagent usage fees. No pretreatment such as membrane or thermal methods is required before electrolysis, thus reducing treatment costs. The treated wastewater also does not require further treatment and can be used directly as an oxidant and process water in the circulating water system, thus reducing system complexity.

[0076] (2) The oxidant generated by the electrolysis of chloride ions contained in the circulating sewage is used to treat the circulating water itself, thereby recycling the chlorine resources in the sewage to a certain extent.

[0077] (3) The investment and operating costs are low, the operation is stable, and the processing capacity can be increased through modular installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a process flow chart of the utility model.

[0079] Figure 1 Explanation of the numbers: 1 is the raw water tank; 2 is the sand filter tower; 3 is the electrochemical scale inhibition device; 4 is the oxidation polarization device; 5 is the buffer tank; 6 is the electric carbon filtration device; 7 is the electric adsorption device; 8 is the electrolytic sterilization device.

[0080] Figure 2 This is a schematic diagram of the electric adsorption principle of the electric adsorption device of the present utility model.

[0081] Figure 2 Explanation of reference numerals: 71 is the cathode plate of the electric adsorption device; 72 is the anode plate of the electric adsorption device; 73 is the cathode adsorption material of the electric adsorption device; 74 is the anode adsorption material of the electric adsorption device; 75 is the power supply of the electric adsorption device; 76 is the cation; 77 is the anion.

[0082] Figure 3 This is a schematic diagram of the electrolytic sterilization principle of the electrolytic sterilization device of the present utility model.

[0083] Figure 3 Explanation of reference numerals: 81 is the anode plate of the electrolytic sterilization device, and 82 is the cathode plate of the electrolytic sterilization device.

[0084] Figure 4 It is the removal rate of total hardness, calcium hardness and total alkalinity at different concentration ratios in the embodiment.

[0085] Figure 5 It is the removal rate of chloride ions at different concentration ratios in the embodiment.

[0086] Figure 6 It is the removal rate of conductivity at different concentration ratios in the embodiment. DETAILED DESCRIPTION

[0087] The specific technical solution of the present utility model is described with reference to the accompanying drawings.

[0088] like Figure 1 As shown, the device for electrochemical pretreatment-electrolysis coupling treatment of power plant circulating water, the circulating water from the raw water tank 1 enters the simulated cooling tower through the lifting pump for circulating water concentration, the concentrated circulating cooling water enters the sand filter tower 2 for filtration, the filtered water enters the electrochemical scale inhibition device 3, in the electrochemical scale inhibition device 3, the temporary hardness is reduced, mainly removing calcium carbonate ions and bicarbonate ions, the electrochemical scale inhibition device 3 requires regular desorption backwashing to determine its hardness removal efficiency, the water flowing out of the electrochemical scale inhibition device 3 enters the oxidation polarization device 4, in the oxidation polarization device 4, the water molecules have polarity under the action of high-voltage static electricity, which plays a role in corrosion inhibition and corrosion prevention. The effluent from the oxidation polarization enters the buffer box 5, and the buffer box 5 enters the electro-carbon filter 6, in which part of the suspended solids are removed. The effluent from the electro-carbon filter 6 enters the electro-adsorption device 7, in which the permanent hardness ions and chloride ions are removed, mainly calcium, magnesium and chloride ions. The effluent from the electro-adsorption device 7 enters the desulfurization system or the replenishment water of the circulating water. The electro-adsorption desorption concentrated water from the electro-adsorption device 7 enters the electrolytic sterilization device 8, in which the chloride ions are oxidized to produce the oxidant hypochlorous acid. The effluent from the electrolytic sterilization device 8 can be used as a bactericide and returned to the desulfurization system before the triplex box.

[0089] like Figure 2 The electric adsorption device 7 shown includes an electric adsorption device cathode plate 71 and an electric adsorption device anode plate 72; the electric adsorption device cathode plate 71 and the electric adsorption device anode plate 72 are respectively connected to the positive and negative poles of the electric adsorption device power supply 75; the electric adsorption device cathode plate 71 and the electric adsorption device anode plate 72 are respectively provided with an electric adsorption device cathode adsorption material 73 and an electric adsorption device anode adsorption material / 74, which are respectively used to adsorb cations 76 and anions 77.

[0090] like Figure 3 As shown, the electrolytic sterilization device 8 includes an electrolytic sterilization device anode plate 81 and an electrolytic sterilization device cathode plate 82.

[0091] In order to reduce energy consumption, obtain an oxidant with higher oxidation performance, and improve the removal effect of chloride ions, the operating principle of the utility model is as follows: the water in the raw water tank 1 enters the simulated cooling tower through a lifting pump for circulating water concentration. The design of the cooling tower ensures the effective cooling and concentration of the water; the concentrated circulating cooling water enters the sand filter tower 2 for filtration. The sand filter tower 2 is filled with quartz sand of different particle sizes, which can effectively remove suspended particles and impurities in the water; the filtered water enters the electrochemical scale inhibition device 3. The electrochemical scale inhibition device 3 mainly removes calcium carbonate ions and bicarbonate ions in the water to reduce temporary hardness; the electrochemical scale inhibition water outlet of the electrochemical scale inhibition device 3 enters the buffer tank 5. When entering the buffer tank 5, the flow rate of the water outlet of the electrochemical scale inhibition device 3 must be reduced. The buffer tank 5 is reasonably designed to balance the water pressure and flow in the system, ensuring the stable operation of the downstream equipment; the water in the buffer tank 5 enters the composite electric carbon filter device 6. The electric carbon filtration device 6 combines activated carbon and electrochemical filtration technology, which can remove suspended matter, organic matter and some ions in the water and improve the water quality; the water filtered by the electric carbon filtration device 6 enters the high-efficiency electric adsorption device 7. The electric adsorption device 7 uses multi-layer adsorption materials, which can efficiently remove permanent hardness ions (such as calcium and magnesium ions) and chloride ions to ensure that the water quality meets the standards for recycling. The concentrated water from the electric adsorption device 7 is passed into the concentrating mechanism in the electric adsorption device 7 to continue to be concentrated. After reaching the concentration upper limit of the electric adsorption device 7, the desorbed concentrated water enters the electrolytic sterilization device 8 for treatment. The desorbed concentrated water enters the electrolytic sterilization device, and the chloride ions are oxidized in the device to generate hypochlorous acid. The hypochlorous acid is returned to the circulating water system as a powerful bactericide to ensure that the microorganisms in the system are effectively controlled; after the desorbed concentrated water from the electric adsorption device 7 enters the electrolytic sterilization device, in order to obtain an oxidant with stronger oxidizing properties, the voltage of the electrolytic sterilization device 8 is appropriately increased.

[0092] Based on the above electrochemical coupling system, the control method of the utility model is: close the drain valve of the sand filter tower 2, open the water inlet valve and water production valve of the sand filter tower 2, start the water pump of the raw water tank 1 to extract the circulating water into the sand filter tower 2; the water produced by the sand filter tower 2 is filtered and overflowed into the electrochemical scale inhibition device 3, and the electrochemical scale inhibition device 3 is started to process the power supply, and the voltage and current are adjusted according to the water quality; the electrochemical scale inhibition device 3 produces water to detect the pH value of the inlet and outlet water and the carbonate hardness and total hardness and other treatment indicators; start the oxidation polarization scale inhibition and anti-corrosion processor high-voltage power supply of the oxidation polarization device 4, and at the same time start the electric heating power supply, and the water produced by the electrochemical scale inhibition device 3 overflows into the oxidation polarization device 4 and enters Perform oxidation polarization scale inhibition and anti-corrosion treatment, adjust the voltage (no current) according to the water quality, extract the oxidation polarization product of the oxidation polarization device 4 into the electric carbon filter device 6 to filter the suspended matter and reduce turbidity; the electric carbon filtration product of the electric carbon filter device 6 enters the electric adsorption device 7, starts the electric adsorption desalination power supply of the electric adsorption device 7, and adjusts the voltage and current on site according to the water quality; the product water is sampled and tested, and the chloride ion, sulfate root and sulfate hardness and other indicators of the inlet and outlet water are tested; the electric adsorption product of the electric adsorption device 7 enters the electrolytic sterilization device 8, starts the electrolytic power supply, adjusts the current and voltage, and takes samples for testing, and the hypochlorous acid, sodium hypochlorite and residual chlorine indicators of the inlet and outlet water are tested.

[0093] The present invention will be further described below with reference to the embodiments.

[0094] 2m 3 / h water flow as an example, the electrochemical scale inhibition device 3 is set to the voltage stabilization working state, the working voltage is 3.2v, the oxidation polarization working voltage is set to 21000v, after passing through the electrochemical scale inhibition device 3 and the oxidation polarization device 4, the treatment effect is as follows Figure 4-Figure 6 shown. Figure 4 It is the removal rate of total hardness, calcium hardness and total alkalinity at different concentration ratios. Figure 5 is the removal rate of chloride ions at different concentration ratios, Figure 6 is the removal rate of conductivity at different concentration ratios, Figure 4-Figure 6 It can be seen that the system used in this utility model has the following removal rates for various indicators: total hardness is 15%-40%, calcium hardness is 25%-50%, total alkalinity is 50%-75%, and chloride ions are about 20%. Figures 4 to 6 As can be seen from the effect diagram, the effect of electrochemical pretreatment-electrolysis coupling in treating power plant circulating water is significant.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An electrochemical pretreatment-electrolysis coupled treatment device for power plant circulating water, characterized in that: It includes a raw water tank (1), a simulated cooling tower, a sand filter tower (2), an electrochemical scale inhibition device (3), an oxidation polarization device (4), a buffer tank (5), an electro-carbon filtration device (6), an electric adsorption device (7), and an electrolytic sterilization device (8) connected in sequence; The circulating water enters the simulated cooling tower from the raw water tank (1) through the lifting pump for circulating water concentration. The concentrated circulating cooling water enters the sand filter tower (2) for filtration. The filtered water enters the electrochemical scale inhibition device (3) to reduce the temporary hardness in the electrochemical scale inhibition device (3); the water flowing out of the electrochemical scale inhibition device (3) enters the oxidation polarization device (4). In the oxidation polarization device (4), the water molecules have polarity under the action of high-voltage static electricity, which plays a role in corrosion inhibition. The oxidation polarization effluent enters the buffer box (5), and the buffer box (5) enters the electro-carbon filter device (6), part of the suspended solids are removed in the electro-carbon filtration device (6), the effluent of the electro-carbon filtration device (6) enters the electro-adsorption device (7), and the permanent hardness ions and chloride ions are removed in the electro-adsorption device (7); the electro-adsorption effluent of the electro-adsorption device (7) enters the desulfurization system or the replenishment water of the circulating water, and the electro-adsorption desorption concentrated water of the electro-adsorption device (7) enters the electrolytic sterilization device (8), and the chloride ions are oxidized in the electrolytic sterilization device (8) to produce the oxidant hypochlorous acid, and the electrolytic sterilization effluent of the electrolytic sterilization device (8) is used as a sterilant and returned to the front of the desulfurization system triplex box.

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