Low-chlorine and low-water electro-deionization device

Abstract

This application discloses an electro-desalination device for low-chlorine electrostatic water, comprising a negative electrode (11), a positive electrode (41), multiple anion exchange membranes (20), and multiple cation exchange membranes (30). The anion exchange membranes (20) and cation exchange membranes (30) are alternately located between the negative electrode (11) and the positive electrode (41), and the membrane adjacent to the positive electrode (41) is a cation exchange membrane (30). A negative electrode chamber (1) is formed between the negative electrode (11) and the adjacent membrane, and a positive electrode chamber (4) is formed between the positive electrode (41) and the adjacent membrane. A desalination chamber (2) and a concentrate chamber (3) are alternately formed between adjacent membranes. The positive electrode chamber (4) and the concentrate chamber (3) are adjacent to each other, and the PEI inlet water of the positive electrode chamber (4) is ultrapure water. The electro-desalination device for low-chlorine electrostatic water provided by this application has an approximately neutral PEO in the effluent from the positive electrode chamber, which significantly reduces the risk of chlorine oxidation.

Description

Technical Field

[0001] This application relates to the field of membrane separation technology, and in particular to an electro-desalination device for low-chlorine water. Background Technology

[0002] Electro-deionization (EDI or Continuous electro-deionization, CEDI) is a membrane separation process that uses ion exchange resins to adsorb anions and cations from a freshwater stream. Simultaneously, under the influence of an electric field, the adsorbed anions and cations migrate through anion and cation exchange membranes to the concentrated water stream, respectively. The result is the removal of ions from the freshwater stream and the enrichment of ions in the concentrated water stream. Compared to ion exchange, electro-deionization has advantages such as not requiring chemical regeneration and providing stable desalination, and is commonly used in the preparation of ultrapure water.

[0003] In recent years, due to the increasing scarcity of water resources, the reuse of wastewater from electrostatic precipitators (including concentrate effluent, positive electrode influent, and negative electrode effluent) has become a common practice. However, because the positive electrode water from electrostatic precipitators contains dissolved chlorine, the wastewater from these precipitators is oxidizing, posing a threat of oxidation to the reverse osmosis membrane and the ion exchange resin inside the electrostatic precipitator, which can easily lead to accidents where the ion exchange resin or reverse osmosis membrane is oxidized.

[0004] To address the aforementioned oxidation and burnout issues, existing electrostatic desalination components have various external structural designs, such as "three-in-three-out", "two-in-three-out", "two-in-two-out", and "one-in-two-out", etc. However, none of these designs have effectively solved the problem of positive electrode water oxidation. Utility Model Content

[0005] To address the aforementioned technical problems, the first objective of this utility model is to provide an electro-desalination device for low-chlorine electrode water. The electro-desalination device for low-chlorine electrode water provided in this application defines a concentrate chamber adjacent to the positive electrode chamber, and the membrane immediately adjacent to the positive electrode chamber is a cation exchange membrane. The inlet water to the positive electrode chamber is ultrapure water, thus preventing anions from entering the positive electrode chamber via electromigration. Simultaneously, since the PEI inlet water to the positive electrode chamber is ultrapure water, the electrochemical process in the positive electrode chamber is simplified, with almost all products being oxygen and hydrogen ions. The hydrogen ions participate in conductivity in an equivalent proportion and are migrated to the adjacent concentrate chamber. Therefore, the PEO effluent from the positive electrode chamber is approximately neutral, significantly reducing the risk of chlorine oxidation.

[0006] The technical solution provided by this utility model is as follows:

[0007] An electro-desalination device for low-chlorine water includes a negative electrode, a positive electrode, multiple anion exchange membranes, and multiple cation exchange membranes.

[0008] Anion exchange membranes and cation exchange membranes are alternately located between the negative and positive electrodes, with the membrane adjacent to the positive electrode being the cation exchange membrane;

[0009] A negative electrode chamber is formed between the negative electrode and the adjacent membrane, a positive electrode chamber is formed between the positive electrode and the adjacent membrane, and fresh water chambers and concentrated water chambers are formed alternately between adjacent membranes;

[0010] The positive electrode chamber and the concentrate chamber are adjacent to each other, and the PEI inlet water for the positive electrode chamber is ultrapure water.

[0011] Preferably, the anion exchange membranes of the negative electrode chamber and the concentrate chamber are adjacent to each other, and the inlet water NEI of the negative electrode chamber is ultrapure water.

[0012] Preferably, the ultrapure water used for the inlet water PEI of the positive electrode chamber and the inlet water NEI of the negative electrode chamber is the effluent DO of the fresh water chamber.

[0013] Preferably, the positive electrode chamber effluent PEO and the negative electrode chamber effluent NEO are combined into electrode water effluent EO; or, the positive electrode chamber effluent PEO, the negative electrode chamber effluent NEO, and the concentrate chamber effluent CO are combined into wastewater RO.

[0014] Preferably, the positive electrode chamber inlet water (PEI), the negative electrode chamber inlet water (NEI), and the freshwater chamber effluent (DO) are combined; and / or,

[0015] The influent CI from the concentrate chamber and the effluent DO from the desalination chamber are combined.

[0016] Preferably, the freshwater chamber and the concentrated water chamber flow in opposite directions; and / or,

[0017] The freshwater chamber and the negative electrode chamber have opposite water flow directions; and / or,

[0018] The freshwater chamber and the positive electrode chamber have opposite water flow directions.

[0019] Preferably, the channel for the freshwater outlet (DO) is folded back inside the device, so that the interface for the freshwater outlet (DO) and the interface for the freshwater inlet (DI) are located on the same side of the device.

[0020] Preferably, the negative electrode chamber further includes a negative electrode insulating plate, which is disposed on the side of the negative electrode away from the diaphragm;

[0021] The positive electrode chamber also includes a positive electrode insulating plate, which is located on the side of the positive electrode away from the membrane;

[0022] A negative electrode clamping plate is also provided on the side of the negative electrode insulating plate away from the negative electrode;

[0023] A positive electrode clamping plate is also provided on the side of the positive electrode insulating plate away from the positive electrode.

[0024] Preferably, a negative electrode frame plate is provided between the negative electrode and the adjacent membrane, and a positive electrode frame plate is provided between the positive electrode and the adjacent membrane;

[0025] A freshwater frame plate is installed between the anion exchange membrane and the cation exchange membrane in the freshwater chamber, and a concentrated water frame plate is installed between the anion exchange membrane and the cation exchange membrane in the concentrated water chamber.

[0026] The negative electrode frame, positive electrode frame, freshwater frame, and concentrated water frame are connected to the water distribution pipeline.

[0027] Preferably, ionic conductors are optionally filled into the negative electrode chamber, the fresh water chamber, the concentrated water chamber, and the positive electrode chamber.

[0028] This application discloses an electro-desalination device for low-chlorine electrode water, comprising a negative electrode, a positive electrode, multiple anion exchange membranes, and multiple cation exchange membranes. Anion exchange membranes and cation exchange membranes are alternately located between the negative and positive electrodes, with the membrane immediately adjacent to the positive electrode being a cation exchange membrane. A negative electrode chamber is formed between the negative electrode and its adjacent membrane, and a positive electrode chamber is formed between the positive electrode and its adjacent membrane. Dilute water chambers and concentrate water chambers are alternately formed between adjacent membranes. The positive electrode chamber and the concentrate water chamber are adjacent, and the PEI (precipitated ionized water) inlet water to the positive electrode chamber is ultrapure water. This application specifies that a concentrate water chamber is adjacent to the positive electrode chamber, and the membrane immediately adjacent to the positive electrode chamber is a cation exchange membrane. The inlet water to the positive electrode chamber is ultrapure water, thus preventing anions such as chloride, sulfate, carbonate, and hydroxide from entering the positive electrode chamber via electromigration. Simultaneously, since the PEI inlet water to the positive electrode chamber is ultrapure water, the electrochemical process in the positive electrode chamber is simplified, and its products are almost entirely oxygen and hydrogen ions. The electrode reactions are as follows:

[0029] 2H₂O→O₂+4H⁺++4e -

[0030] Hydrogen ions participate in electrical conduction in equal amounts and are migrated to the adjacent concentrate chamber. Therefore, the PEO in the effluent from the positive electrode chamber is approximately neutral, significantly reducing the risk of chlorine oxidation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the principle of the low-chlorine electro-desalination device for the electrode water in this embodiment of the present invention (the negative electrode chamber and the fresh water chamber are adjacent; the PEO effluent from the positive electrode chamber and the NEO effluent from the negative electrode chamber are combined into the electrode water effluent EO; the PEI effluent from the positive electrode chamber, the NEI effluent from the negative electrode chamber and the DO effluent from the fresh water chamber are combined).

[0033] Figure 2This is a schematic diagram of the principle of the low-chlorine electrode water electro-desalination device in this embodiment of the utility model (the negative electrode chamber and the concentrated water chamber are adjacent; the positive electrode chamber effluent PEO and the negative electrode chamber effluent NEO are combined into electrode water effluent EO; the positive electrode chamber inlet PEI, the negative electrode chamber inlet NEI, and the fresh water chamber effluent DO are combined).

[0034] Figure 3 This is a schematic diagram of the principle of the low-chlorine electrode water electro-desalination device in this embodiment of the utility model (the negative electrode chamber and the concentrate chamber are adjacent; the positive electrode chamber outlet PEO and the negative electrode chamber outlet NEO are combined into electrode water outlet EO; the positive electrode chamber inlet PEI, the negative electrode chamber inlet NEI and the fresh water chamber outlet DO are combined; the concentrate chamber inlet CI and the fresh water chamber outlet DO are combined).

[0035] Figure 4 This is a schematic diagram of the principle of the low-chlorine electro-desalination device in this embodiment of the utility model (the negative electrode chamber and the concentrate chamber are adjacent; the positive electrode chamber effluent PEO, the negative electrode chamber effluent NEO and the concentrate chamber effluent CO are combined into RO drainage; the positive electrode chamber influent PEI, the negative electrode chamber influent NEI and the freshwater chamber effluent DO are combined; the concentrate chamber influent CI and the freshwater chamber effluent DO are combined).

[0036] Figure 5 This is a schematic diagram of the principle of the low-chlorine electro-desalination device in this embodiment of the present invention (the negative electrode chamber and the concentrate chamber are adjacent; the positive electrode chamber effluent PEO, the negative electrode chamber effluent NEO, and the concentrate chamber effluent CO are combined into RO drainage; the positive electrode chamber influent PEI, the negative electrode chamber influent NEI, and the freshwater chamber effluent DO are combined; the concentrate chamber influent CI and the freshwater chamber effluent DO are combined; the freshwater chamber influent DI and the freshwater chamber effluent DO have opposite water flow directions).

[0037] Figure 6 This is a schematic diagram of the principle of the low-chlorine electro-desalination device in this embodiment of the present invention (the negative electrode chamber and the concentrate chamber are adjacent; the positive electrode chamber outlet PEO, the negative electrode chamber outlet NEO, and the concentrate chamber outlet CO are combined into drainage RO; the positive electrode chamber inlet PEI, the negative electrode chamber inlet NEI, and the freshwater chamber outlet DO are combined; the concentrate chamber inlet CI and the freshwater chamber outlet DO are combined; the freshwater chamber inlet DI and the freshwater chamber outlet DO have opposite water flow directions, and the freshwater chamber outlet DO channel is turned back inside the device so that the interface of the freshwater chamber outlet DO and the interface of the freshwater chamber inlet DI are located on the same side of the device).

[0038] Figure labels: 1-Negative electrode chamber; 11-Negative electrode; 12-Negative electrode insulating plate; 13-Negative electrode clamping plate; 2-Desalinated water chamber; 3-Concentrated water chamber; 4-Positive electrode chamber; 41-Positive electrode; 42-Positive electrode insulating plate; 43-Positive electrode clamping plate; 20-Anion exchange membrane; 30-Cation exchange membrane; DI-Desalinated water inlet; DO-Desalinated water effluent; CI-Concentrated water inlet; CO-Concentrated water effluent; EI-Electrode water inlet; EO-Inlet and outlet water; RO-Mixed wastewater. Anion exchange resin, Cation exchange resin. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0041] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0043] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0044] As shown in the figure, this embodiment of the invention provides an electro-desalination device for low-chlorine water, including a negative electrode 11, a positive electrode 41, multiple anion exchange membranes 20, and multiple cation exchange membranes 30.

[0045] Anion exchange membrane 20 and cation exchange membrane 30 are alternately located between negative electrode 11 and positive electrode 41, and the membrane adjacent to positive electrode 41 is cation exchange membrane 30;

[0046] Negative electrode 11 forms a negative electrode chamber 1 with the adjacent membrane, positive electrode 41 forms a positive electrode chamber 4 with the adjacent membrane, and fresh water chamber 2 and concentrated water chamber 3 are alternately formed between adjacent membranes;

[0047] The positive electrode chamber 4 is adjacent to the concentrate chamber 3, and the PEI inlet water of the positive electrode chamber 4 is ultrapure water.

[0048] Regarding the issue of easy oxidation during the operation of the electrostatic desalination unit, the applicant, after research and analysis, summarized the reasons as follows:

[0049] In existing electrostatic desalination units, a freshwater chamber is typically adjacent to the positive electrode chamber. The inlet water to the positive electrode chamber and the inlet water to the negative electrode chamber are combined into the electrode water inlet, and the outlet water to the positive electrode chamber and the outlet water to the negative electrode chamber are combined into the electrode water outlet. The electrode water inlet is usually the electrostatic desalination feed water. Because the electrostatic desalination feed water contains chloride ions, and because chloride ions migrate from the adjacent freshwater chamber into the positive electrode chamber via electromigration, the chloride ion concentration in the positive electrode chamber is significantly higher than the chloride ion concentration in the electrostatic desalination feed water.

[0050] If the chloride ion concentration in the positive electrode chamber inlet is CCl1 (ppm) and the flow rate is F1; and the chloride ion concentration in the freshwater chamber adjacent to the positive electrode is CCl2 (ppm) and the flow rate is F2, and since the primary application of electro-desalination is the production of ultrapure water, it can be assumed that all chloride ions in the freshwater chamber adjacent to the positive electrode chamber migrate into the positive electrode chamber via electromigration (or the residual chloride ions in the freshwater are negligible). Then, the chlorine weight concentration (ppm) in the water flow to the positive electrode chamber is:

[0051] CCl2≈(C CL1 *F1+C CL2 *F2) / F1

[0052] Existing electrostatic desalination units operate normally under conditions of a large residual current. The so-called excess current Ie refers to the portion of the operating current Iw remaining after deducting the effective current Io required for migrating inherent ions in the water, i.e., Ie = Iw - Io. It is generally believed that due to the large residual current during electrostatic desalination, all chloride ions in the positive electrode chamber are electrolyzed into chlorine gas, and a portion of the excess current is used to generate oxygen.

[0053] To illustrate the point, assume the chloride ion content of both the positive electrode inlet water and the freshwater inlet water is 5 ppm, the positive electrode water flow rate is 30 L / h, the adjacent freshwater inlet flow rate is 100 L / h, and the chloride content of the positive electrode inlet water is:

[0054] C Cl2 = (5*30 + 5*100) / 30 = 22ppm

[0055] For typical large-scale electrostatic precipitators, the concentrate flow rate is approximately 10% of the desalination flow rate, and the electrode water effluent flow rate (including both positive and negative electrode effluent) is approximately 1% of the desalination flow rate. Under these conditions, the electrostatic precipitator wastewater flow rate is approximately 20 times the positive electrode water effluent flow rate. Therefore, the chlorine content in the electrostatic precipitator wastewater is approximately 1.1 ppm. After this water is mixed with approximately 10 times its volume of raw water during reuse, the chlorine concentration is approximately 0.1 ppm. This chlorine concentration poses a fatal threat to both the ion exchange resin and the reverse osmosis membrane in the electrostatic precipitator. Therefore, it is urgent to reduce the chlorine concentration in the positive electrode effluent to address the problems existing in current electrostatic precipitators.

[0056] To address the aforementioned issues, this application discloses an electro-desalination device for low-chlorine electrostatic water, comprising a negative electrode 11, a positive electrode 41, multiple anion exchange membranes 20 and multiple cation exchange membranes 30, wherein the anion exchange membranes 20 and cation exchange membranes 30 are alternately located between the negative electrode 11 and the positive electrode 41, and the membrane adjacent to the positive electrode 41 is a cation exchange membrane 30; a negative electrode chamber 1 is formed between the negative electrode 11 and the adjacent membrane, and a positive electrode chamber 4 is formed between the positive electrode 41 and the adjacent membrane; a desalination chamber 2 and a concentrate chamber 3 are alternately formed between adjacent membranes; the positive electrode chamber 4 is adjacent to the concentrate chamber 3, and the PEI inlet water of the positive electrode chamber 4 is ultrapure water. This application specifies that a concentrate chamber 3 is adjacent to the positive electrode chamber 4, and the membrane immediately adjacent to the positive electrode chamber 4 is a cation exchange membrane 30. The feed water to the positive electrode chamber 4 is ultrapure water, thus preventing anions such as chloride, sulfate, carbonate, and hydroxide from entering the positive electrode chamber 4 via electromigration. Furthermore, since the PEI feed water to the positive electrode chamber 4 is ultrapure water, the electrochemical process in the positive electrode chamber 4 is simplified, and its products are almost entirely oxygen and hydrogen ions. The electrode reactions are as follows:

[0057] 2H₂O→O₂+4H⁺++4e -

[0058] Hydrogen ions participate in conductivity in equal amounts and are migrated to the adjacent concentrate chamber 3. Therefore, the PEO in the effluent from the positive electrode chamber is approximately neutral, which significantly reduces the risk of chlorine oxidation.

[0059] Preferably, the anion exchange membrane 20 of the negative electrode chamber 1 and the concentrate chamber 3 are adjacent to each other, and the inlet water NEI of the negative electrode chamber 1 is ultrapure water.

[0060] Negative electrode chamber 1 can be adjacent to the cation exchange membrane 30 of fresh water chamber 2 or the anion exchange membrane 20 of concentrated water chamber 3, and can be used in conjunction with the above-mentioned positive electrode chamber to achieve the effect of low-chlorine electrode water.

[0061] More preferably, the anion exchange membrane 20 of the negative electrode chamber 1 and the concentrate chamber 3 are adjacent, and at this time the inlet water NEI of the negative electrode chamber 1 is ultrapure water.

[0062] The analysis of this problem is as follows: In existing electro-deionization units, the chamber adjacent to the negative electrode is usually a freshwater chamber, and the inlet water to the negative electrode chamber is usually the electro-deionization feed water. Due to electromigration, cations in the freshwater chamber adjacent to the negative electrode chamber migrate into the negative electrode chamber. Combined with the cations inherent in the inlet water to the negative electrode chamber, the cation concentration in the negative electrode chamber is significantly greater than the cation concentration in the electro-deionization feed water.

[0063] The main electrochemical reaction in the negative electrode chamber is:

[0064] 2H + +2e - →H2

[0065] 2Na + +2H₂O + 2e - →H₂ + 2NaOH

[0066] Ca 2+ +2H₂O + 2e - →H2+Ca(OH)2

[0067] Mg 2+ +2H₂O + 2e - →H2+Mg(OH)2

[0068] 2H₂O + 2e⁻ → H₂ + 2OH⁻ -

[0069] Therefore, the effluent from the negative electrode is strongly alkaline and contains concentrated calcium and magnesium ions. Calcium and magnesium ions have a strong tendency to form scale in the alkaline environment of the negative electrode chamber. Once solid scale forms, the water flow in the negative electrode chamber loses its uniformity. Long-term accumulation of this type of scale can lead to insufficient heat dissipation in the negative electrode chamber, resulting in a burn-out accident.

[0070] The best existing solution to this problem is to establish separate inlet and / or outlet pipelines for electrode water to monitor the electrode water flow rate in real time. When this flow rate decreases significantly, the negative electrode chamber should be cleaned promptly. However, the optimal solution for real-time electrode water flow monitoring is to monitor the inlet electrode water, as the outlet electrode water contains a mixture of explosive gases including hydrogen, chlorine, and oxygen, making flow rate monitoring difficult and hindering the release of these gases. Even monitoring the inlet electrode water has its limitations, including time lag and the need for system shutdown to clean the negative electrode chamber.

[0071] This application adopts a scheme where the anion exchange membrane 20 of the negative electrode chamber 1 and the concentrate chamber 3 are adjacent, and the influent NEI of the negative electrode chamber 1 is ultrapure water. Because the presence of the anion exchange membrane 20 prevents cations such as calcium, magnesium, and sodium from entering the negative electrode chamber 1 via electromigration, and because the influent NEI of the negative electrode chamber 1 is ultrapure water with a very low cation concentration, the electrochemical process in the negative electrode chamber 1 is simplified, and its products are hydrogen gas and hydroxide ions.

[0072] 2H2O+2e- →H2+2OH -

[0073] Hydroxide ions participate in conductivity in equal amounts and migrate to the adjacent concentrate chamber 3. Therefore, the water in the negative electrode chamber 1 is approximately neutral; at the same time, the absence of calcium and magnesium ions greatly reduces the possibility of scaling in the negative electrode chamber 1.

[0074] Preferably, the ultrapure water used for the inlet water PEI of the positive electrode chamber 4 and the inlet water NEI of the negative electrode chamber 1 is the effluent DO of the fresh water chamber 2.

[0075] Preferably, the ultrapure water used for the inlet PEI of the positive electrode chamber 4 is the DO effluent from the fresh water chamber 2, and preferably, the ultrapure water used for the inlet NEI of the negative electrode chamber 1 is the DO effluent from the fresh water chamber 2.

[0076] Commonly used electro-desalination components are used to produce ultrapure water. The resistivity of the DO in the desalination product is generally greater than 15 MΩ·cm (the resistivity of ultrapure water is broadly greater than 1 MΩ·cm, usually greater than 15 MΩ·cm, and specifically greater than 18 MΩ·cm). Reusing the DO effluent from the desalination chamber 2 can save resources and will not have an adverse effect on the normal operation of the equipment.

[0077] Preferably, the PEO effluent from the positive electrode chamber 4 and the NEO effluent from the negative electrode chamber 1 are combined into the electrode water effluent EO; or, the PEO effluent from the positive electrode chamber 4, the NEO effluent from the negative electrode chamber 1, and the CO effluent from the concentrate chamber 3 are combined into the drainage RO.

[0078] Preferably, the PEI inlet water of positive electrode chamber 4, the NEI inlet water of negative electrode chamber 1, and the DO outlet water of freshwater chamber 2 are combined; and / or,

[0079] The inlet CI of concentrate chamber 3 and the outlet DO of desalination chamber 2 are combined.

[0080] The following is an analysis of the external structural problems of existing electrostatic precipitators: The most basic water circuit design of electrostatic precipitators is "three inlets and three outlets," meaning that separate interfaces are provided for freshwater inlet, freshwater outlet, concentrated water inlet, concentrated water outlet, and electrode water inlet and outlet. This technical solution is still common and the safest and most reliable, but the pipeline installation is relatively complex. Existing technology includes a "two inlets and three outlets" solution that combines the concentrated water inlet and electrode water inlet. The disadvantage of this solution is that it can only detect the electrode water outlet flow rate. However, because the electrode water flow rate is very low and carries explosive gases, a float flow meter is usually required for detection. A float flow meter requires a relatively long flow channel from bottom to top. Therefore, the electrode water usually needs to flow downwards first, then upwards through the float flow meter, and also through a flow regulation control valve. This hinders the smooth venting of the mixed explosive gases contained in the electrode water, creating a safety hazard. Existing technology also includes a "two inlets and two outlets" solution that combines the concentrated water inlet and electrode water inlet, and the concentrated water outlet and electrode water outlet. This technical solution completely makes it impossible to detect the flow rate of the electrode water, and the electrode water containing oxidizing and explosive gases cannot be separated from the concentrate water with reuse value. This is the main cause of oxidation accidents in the reuse of electrostatic precipitator effluent, and also poses a hidden danger of explosive gases gradually accumulating in the electrostatic precipitator equipment plant.

[0081] The solution provided in this application solves the problem of oxidizing PEO in the effluent of the positive electrode chamber 4 and the scaling problem in the negative electrode chamber 1, thus greatly reducing the necessity for real-time control of the electrode water flow rate. Therefore, eliminating the need for a separate electrode water pipeline and electrode water flow detection device becomes a feasible technical solution.

[0082] Assuming the ultrapure water used as the influent is DO (dissolved oxygen) from the second desalination chamber, with a resistivity of 15 MΩ·cm (conductivity of 0.067 μS / cm), and assuming that the conductivity, excluding the contribution of water ionization (0.055 μS / cm), is entirely contributed by sodium chloride, the chloride ion concentration is approximately 0.0034 ppm. Even if all these chloride ions are electrolyzed into chlorine gas, the chlorine concentration in the PEO (polyurethane) effluent from the positive electrode chamber is approximately 0.0034 ppm. As mentioned earlier, the CO flow rate of the concentrate effluent from a large-scale electrostatic precipitator is typically 20 times the PEO flow rate from the positive electrode chamber. Therefore, the chlorine concentration in the RO (return oxygen) effluent from the electrostatic precipitator, including the PEO from the positive electrode chamber, the NEO from the negative electrode chamber, and the CO from the concentrate effluent, is approximately 0.00017 ppm. In reuse processes, the wastewater from the electrostatic precipitator is typically mixed with approximately 10 times its volume of raw water. After mixing, the chlorine concentration in the PEO (polyionomer oxide) effluent from the positive electrode chamber of the electrostatic precipitator is as low as 0.00002 ppm (0.02 ppb). This concentration of chlorine has negligible oxidizing effect on the membrane and ion exchange resin. Therefore, from the perspective of reusing the wastewater from the electrostatic precipitator, it is unnecessary to install a separate electrode water drainage pipeline; the electrode water drainage pipeline and the concentrate effluent pipeline can be combined within the electrostatic precipitator.

[0083] Therefore, this application can combine the PEO effluent from positive electrode chamber 4 and the NEO effluent from negative electrode chamber 1 into EO effluent; or, combine the PEO effluent from positive electrode chamber 4, the NEO effluent from negative electrode chamber 1, and the CO effluent from concentrate chamber 3 into RO effluent.

[0084] Furthermore, the PEI inlet water of positive electrode chamber 4, the NEI inlet water of negative electrode chamber 1, and the DO outlet water of freshwater chamber 2 can be combined, eliminating the need for the EI inlet water in the existing technology. Similarly, the CI inlet water of concentrate chamber 3 and the DO outlet water of freshwater chamber 2 can be combined, eliminating the need for the CI inlet water in the existing technology.

[0085] When the PEO effluent from positive electrode chamber 4, the NEO effluent from negative electrode chamber 1, and the CO effluent from concentrate chamber 3 are combined into RO effluent, and the PEI effluent from positive electrode chamber 4, the NEI effluent from negative electrode chamber 1, and the DO effluent from freshwater chamber 2 are combined, and the CI effluent from concentrate chamber 3 and the DO effluent from freshwater chamber 2 are combined, the CO effluent from concentrate chamber and the EO effluent from electrode chamber 2 in the existing technology are merged, thereby realizing the most simplified external structure of the electro-deionization component with "one inlet and two outlets", and at the same time solving the technical problems of electrode oxidation and scale formation in the electrode chamber.

[0086] The above merging is achieved by connecting the corresponding pipelines.

[0087] Preferably, the freshwater chamber 2 and the concentrated water chamber 3 have opposite water flow directions; and / or,

[0088] Freshwater chamber 2 flows in the opposite direction to negative electrode chamber 1; and / or,

[0089] The freshwater chamber 2 and the positive electrode chamber 4 have opposite water flow directions.

[0090] In this application, setting the water flow direction of the desalination chamber 2 and the concentrate chamber 3 in opposite directions can significantly reduce the possibility of scaling in the concentrate chamber. Setting the water flow direction of the desalination chamber 2 and the negative electrode chamber 1 in opposite directions simplifies the internal structure of the electrostatic precipitator. Similarly, setting the water flow direction of the desalination chamber 2 and the positive electrode chamber 4 in opposite directions also simplifies the internal structure of the electrostatic precipitator, facilitating the installation and fixing of pipes and other structures. When all three water flow directions are reversed, the effect is even better, and the piping structure is further simplified.

[0091] Preferably, the channel for the DO outlet of the freshwater chamber 2 is folded back inside the device, so that the interface for the DO outlet of the freshwater chamber 2 and the interface for the DI inlet of the freshwater chamber 2 are located on the same side of the device.

[0092] Preferably, the outlet water (DO) channel of freshwater chamber 2 is folded back inside the device, so that the outlet water (DO) interface of freshwater chamber 2 and the inlet water (DI) interface of freshwater chamber 2 are located on the same side of the device, so as to facilitate the pipeline connection of the electro-deionization device.

[0093] Preferably, the negative electrode chamber 1 further includes a negative electrode insulating plate 12, which is disposed on the side of the negative electrode 11 away from the diaphragm;

[0094] The positive electrode chamber 4 also includes a positive electrode insulating plate 42, which is located on the side of the positive electrode 41 away from the diaphragm.

[0095] A negative electrode clamping plate 13 is also provided on the side of the negative electrode insulating plate 12 away from the negative electrode 11;

[0096] A positive electrode clamping plate 43 is also provided on the side of the positive electrode insulating plate 42 away from the positive electrode 41.

[0097] Preferably, the positive and negative terminals have an insulating plate and a clamping plate, respectively, and are connected by bolts or other methods known in the art.

[0098] Preferably, a negative electrode frame plate is provided between the negative electrode 11 and the adjacent membrane, and a positive electrode frame plate is provided between the positive electrode 41 and the adjacent membrane.

[0099] A freshwater frame plate is provided between the anion exchange membrane 20 and the cation exchange membrane 30 in the freshwater chamber 2, and a concentrated water frame plate is provided between the anion exchange membrane 20 and the cation exchange membrane 30 in the concentrated water chamber 3.

[0100] The negative electrode frame, positive electrode frame, freshwater frame, and concentrated water frame are connected to the water distribution pipeline.

[0101] The preferred configuration includes a negative electrode frame plate, a positive electrode frame plate, a freshwater frame plate, and a concentrate frame plate, which separate the negative electrode 11, the positive electrode 41, and the membrane. Each frame plate is also used to connect to the corresponding water distribution pipe.

[0102] Preferably, ion conductors are optionally filled into the negative electrode chamber 1, the fresh water chamber 2, the concentrated water chamber 3, and the positive electrode chamber 4.

[0103] The negative electrode chamber 1, the desalination chamber 2, the concentrate chamber 3, and the positive electrode chamber 4 are preferably filled with ion conductors, which are preferably anion exchange resins, cation exchange resins, or mixed ion exchange resins. Commonly used anion exchange resins, cation exchange resins, or mixed ion exchange resins in the art can all be used as fillers, and this application has no particular limitations.

[0104] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-chlorine and deionized water producing electrodeionization device, characterized by, It includes a negative electrode (11), a positive electrode (41), multiple anion exchange membranes (20), and multiple cation exchange membranes (30). Anion exchange membrane (20) and cation exchange membrane (30) are alternately located between the negative electrode (11) and the positive electrode (41), and the membrane adjacent to the positive electrode (41) is the cation exchange membrane (30); A negative electrode chamber (1) is formed between the negative electrode (11) and the adjacent membrane, a positive electrode chamber (4) is formed between the positive electrode (41) and the adjacent membrane, and a fresh water chamber (2) and a concentrated water chamber (3) are alternately formed between adjacent membranes; The positive electrode chamber (4) is adjacent to the concentrate chamber (3), and the PEI inlet water of the positive electrode chamber (4) is ultrapure water.

2. The electrical desalination device of claim 1, wherein, The anion exchange membrane (20) of the negative electrode chamber (1) and the concentrate chamber (3) are adjacent, and the NEI water inlet of the negative electrode chamber (1) is ultrapure water.

3. The electrical desalination device according to any one of claims 1-2, characterized in that, The ultrapure water used for the inlet water PEI of the positive electrode chamber (4) and the inlet water NEI of the negative electrode chamber (1) is the effluent DO of the fresh water chamber (2).

4. The electrical desalination device of claim 2, wherein, The PEO effluent from the positive electrode chamber (4) and the NEO effluent from the negative electrode chamber (1) are combined into the EO effluent; or, the PEO effluent from the positive electrode chamber (4), the NEO effluent from the negative electrode chamber (1), and the CO effluent from the concentrate chamber (3) are combined into the RO effluent.

5. The electrical desalination device of claim 2, wherein, Positive electrode chamber (4) inlet water PEI, negative electrode chamber (1) inlet water NEI and freshwater chamber (2) effluent water DO combined; and / or, The concentrate chamber (3) inlet CI and the desalination chamber (2) outlet DO are combined.

6. The electrical desalination device of any one of claims 1-2, wherein, The freshwater chamber (2) and the concentrated water chamber (3) have opposite water flow directions; and / or, The freshwater chamber (2) and the negative electrode chamber (1) have opposite water flow directions; and / or, The freshwater chamber (2) and the positive electrode chamber (4) have opposite water flow directions.

7. The electrical desalination device of claim 6, wherein, The outlet DO channel of the freshwater chamber (2) is turned back inside the device, so that the outlet DO interface of the freshwater chamber (2) and the inlet DI interface of the freshwater chamber (2) are located on the same side of the device.

8. The electrical desalination device of claim 1, wherein, The negative electrode chamber (1) also includes a negative electrode insulating plate (12), which is located on the side of the negative electrode (11) away from the diaphragm; The positive electrode chamber (4) also includes a positive electrode insulating plate (42), which is located on the side of the positive electrode (41) away from the membrane; A negative electrode clamping plate (13) is also provided on the side of the negative electrode insulating plate (12) away from the negative electrode (11); A positive electrode clamping plate (43) is also provided on the side of the positive electrode insulating plate (42) away from the positive electrode (41).

9. The electrical desalination device of claim 8, wherein, A negative electrode frame plate is provided between the negative electrode (11) and the adjacent membrane, and a positive electrode frame plate is provided between the positive electrode (41) and the adjacent membrane; A freshwater frame plate is provided between the anion exchange membrane (20) and the cation exchange membrane (30) in the freshwater chamber (2), and a concentrated water frame plate is provided between the anion exchange membrane (20) and the cation exchange membrane (30) in the concentrated water chamber (3); The negative electrode frame, positive electrode frame, freshwater frame, and concentrated water frame are connected to the water distribution pipeline.

10. The electrical desalination device of any one of claims 1-2, 4-5, 7-9, wherein, Ionic conductors may be randomly selected from the negative electrode chamber (1), the fresh water chamber (2), the concentrated water chamber (3), and the positive electrode chamber (4).

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