Continuous electrodeionization (EDI) water inlet system and method for preventing membrane stack from scaling

Abstract

The invention relates to the technical field of water treatment, in particular to a continuous electrodeionization ED I water inlet system and method for preventing membrane stack scaling. The system comprises a fresh water chamber, a concentrated water chamber, a fresh water chamber water inlet pipe, a fresh water chamber water outlet pipe, a concentrated water chamber water inlet pipe and a concentrated water chamber water outlet pipe, the fresh water chamber water inlet pipe is connected with an inlet of the fresh water chamber, an outlet of the fresh water chamber is connected with the fresh water chamber water outlet pipe, the concentrated water chamber water inlet pipe is connected with an inlet of the concentrated water chamber, and an outlet of the concentrated water chamber is connected with the concentrated water chamber water outlet pipe; the fresh water chamber water outlet pipe comprises a first water outlet pipe and a second water outlet pipe; the first water outlet pipe is connected with a fresh water receiving device; the second water outlet pipe is connected with the concentrated water chamber water inlet pipe or the concentrated water chamber water outlet pipe. The invention aims to reduce the concentration of the concentrated water chamber through a waterway design for prolonging the service life of the ED I equipment and improving the use stability of the ED I equipment so as to avoid scaling of the concentrated water chamber; the chlorine content in the anode chamber is reduced, and the resin is effectively prevented from being oxidized.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a continuous electrodeionization (EDI) water inlet system and method for preventing membrane stack scaling. Background Art

[0002] EDI is mainly used to remove ions from water treated by reverse osmosis (RO) and other purification equipment. EDI is a process used to make ultrapure water systems. An EDI membrane stack mainly consists of alternating anion and cation exchange membranes, concentrated water chambers, anion and cation exchange resins, fresh water chambers and anion / cation electrodes (see Figure 1 :Working principle diagram of EDI). Ion exchange resin is sandwiched between anion / cation exchange membranes to form a single treatment unit and a fresh water chamber. In the first generation of EDI technology, the units are separated by mesh to form a concentrated water chamber. In the second generation of EDI technology, resin is also placed in the concentrated water chamber, so there is no need for concentrated water circulation and polar water discharge, and the operation is simpler. The ultra-limiting current causes a large number of hydrogen ions and hydroxide ions produced by water electrolysis to regenerate the ion exchange resin. Compared with traditional ion exchange, the resin in the electrodeionization EDI membrane stack is continuously regenerated by water electrolysis, and it works continuously without acid-base chemical regeneration.

[0003] The EDI membrane stack divides the inlet water flow into two independent water flows: the production water flow (generally the highest water recovery rate is 95%) and the concentrate water flow (usually 5-10%, which can be recycled back to the RO inlet water). Although the inlet water conditions of the EDI membrane stack greatly reduce the chance of blockage inside the module, since the EDI inlet water contains more solutes, desalination precipitation is formed in the concentrate water chamber. As the water treatment equipment runs for a longer time, the internal waterway of the EDI membrane stack may still be blocked.

[0004] After continuous electro-desalination by the EDI module, 90% to 95% of the ions are transferred from the fresh water chamber to the concentrated water chamber, and the hardness of the concentrated water chamber increases, which may cause some ions to exceed their solubility limit, thus forming precipitation, which is easy to cause scaling in the concentrated water chamber. At the same time, the higher pH value of the concentrated water chamber during operation will promote the precipitation of some ions. The increase or decrease in temperature may affect the solubility of ions and cause scaling. Changes in the quality of the inlet water, such as hardness, silicon content, iron content, etc., may affect the scaling tendency of the EDI concentrated water chamber. Lack of regular chemical cleaning and maintenance may lead to the accumulation of dirt and sediment. In addition, improper waterway design may cause the water flow rate in some areas to decrease, thereby increasing the risk of scaling. Scaling in the EDI concentrated water chamber will increase the pressure difference between the concentrated water inlet and outlet, reduce the current flow, and affect the performance of the EDI components. Scaling will cause the resistivity of the produced water to decrease, affecting the quality of the produced water. When the scaling is severe, it will block the concentrated water flow channel of the component, causing the component to be destroyed due to internal heating, seriously affecting the service life of the EDI device. Scaling in the EDI concentration chamber will also reduce the utilization rate of water in the EDI system, increase the cleaning frequency, reduce the performance of the resin and membrane, and increase the system operating costs.

[0005] With the development of EDI technology, the flow path of EDI membrane stacks has also changed. The performance of EDI membrane stacks has been continuously improved, and the requirements for raw water hardness have gradually softened, such as concentrated water without adding salt. Due to the different flow paths of EDI membrane stacks, the treatment methods for industrial applications are also different, but there are relatively few reports on EDI flow path design, and there are few publicly published materials or experimental data. When designing the flow path of the EDI module, factors such as the hardness, temperature, pH value, SiO2, and oxides of the inlet water need to be considered, because these will affect the operation of the EDI system. For example, too high inlet water hardness may cause scaling on the membrane surface of the concentrated water channel, affecting the quality of the produced water.

[0006] About 70% of the electric energy of the continuous electrodeionization (EDI) module is consumed in the ionization of water. Therefore, during the operation of the EDI module, a large amount of hydrogen ions and hydroxide ions are continuously generated. The surface of the anion membrane in the concentrated water chamber of the EDI membrane block is most susceptible to scaling because the pH value is high and the concentration of scaling substances is also high. In order to ensure the desalination rate, a sufficiently large working current must be maintained, so the method of reducing the current cannot be used to reduce the ionization of water and reduce the pH value. Therefore, the main method to prevent scaling of the EDI module is to strictly control the content of scaling substances in the inlet water. For EDI membrane stacks, the main cause of EDI failure is oxidation of the membrane stack, which is usually caused by residual chlorine. Oxidation destroys the cross-linking of the ion exchange resin, thereby destroying the internal structure of the resin. Once the cross-linking is destroyed, the resin will swell, resulting in an increase in the pressure drop of the membrane stack. The damage caused by oxidation cannot be restored. The only solution at present is to replace the ion exchange resin and membrane inside the membrane stack. The above two points will evenly shorten the service life of the EDI device.

[0007] Therefore, it is very important to design a flow path design for the EDI module that is both efficient and reliable and can meet the needs of high-purity water preparation, based on comprehensive consideration of the pretreatment of the incoming water, the ion removal efficiency, and the long-term stability and maintenance requirements of the system. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a continuous electrodeionization (EDI) water inlet system and method for preventing membrane stack scaling. The present invention provides the following technical solutions:

[0009] The present invention provides a continuous electrodeionization water inlet system for preventing membrane stack scaling, the system comprising a fresh water chamber, a concentrated water chamber, a fresh water chamber water inlet pipe, a fresh water chamber water outlet pipe, a concentrated water chamber water inlet pipe and a concentrated water chamber water outlet pipe, wherein:

[0010] The fresh water chamber inlet pipe is connected to the fresh water chamber inlet, the fresh water chamber outlet is connected to the fresh water chamber outlet pipe, the concentrated water chamber inlet pipe is connected to the concentrated water chamber inlet, and the concentrated water chamber outlet is connected to the concentrated water chamber outlet pipe;

[0011] The fresh water chamber outlet pipe comprises a first outlet pipe and a second outlet pipe, wherein the first outlet pipe is connected to the fresh water receiving device;

[0012] The second water outlet pipe is connected to the concentrated water chamber water inlet pipe or the concentrated water chamber water outlet pipe.

[0013] Specifically, pressure gauges are provided on the fresh water chamber water inlet pipe, the first water outlet pipe, the concentrated water chamber water inlet pipe and the concentrated water chamber water outlet pipe.

[0014] Specifically, when the second water outlet pipe is connected to the concentrate chamber water inlet pipe, a flow alarm and a flow meter are provided on the concentrate chamber water inlet pipe.

[0015] Specifically, when the second water outlet pipe is connected to the concentrate water chamber water outlet pipe, a flow alarm and a flow meter are provided on the concentrate water chamber water outlet pipe.

[0016] Specifically, the first water outlet pipe is provided with a flow alarm, a flow meter, a resistivity meter and a conductivity meter.

[0017] The present invention also provides a continuous electrodeionization water inlet method for preventing membrane stack scaling, characterized in that the system as described above is used, and the method comprises:

[0018] After the raw water enters the fresh water chamber through the fresh water chamber inlet pipe and is treated, the fresh water is discharged from the fresh water chamber outlet;

[0019] A portion of the fresh water enters the fresh water receiving device through the first water outlet pipe;

[0020] The remaining fresh water enters the concentrated water chamber through the second water outlet and the second water outlet pipe.

[0021] Specifically, the remaining fresh water enters the concentrated water chamber through the second outlet pipe, including:

[0022] The remaining fresh water enters the concentrate chamber through the second outlet pipe, the concentrate chamber inlet pipe, and the concentrate chamber inlet for treatment to obtain concentrated water, which is discharged through the concentrate chamber outlet pipe.

[0023] Specifically, the remaining fresh water enters the concentrated water chamber through the second outlet pipe, including:

[0024] The remaining fresh water passes through the second outlet pipe, the outlet pipe of the concentrate chamber, and the outlet of the concentrate chamber and enters the concentrate chamber for treatment to obtain concentrate;

[0025] The concentrated water is discharged through the concentrated water chamber water inlet pipe.

[0026] Specifically, the flow rate of the water inlet pipe of the fresh water chamber is 105%-110% of the standard water production of the membrane stack.

[0027] Specifically, the water flow ratio in the first water outlet pipe and the second water outlet pipe is 10:1 to 11:1.

[0028] Technical effects and advantages of the present invention:

[0029] The present invention aims to improve the operating life and stability of EDI equipment through a water channel design, which is used to reduce the concentration in the concentrate chamber, thereby avoiding scaling in the concentrate chamber; reduce the chlorine content in the anode chamber, and effectively avoid oxidation of the resin. The water channel design has a protective effect on the concentrate chamber and the anode chamber without affecting the water production. The water inlet to the concentrate chamber is the water produced by the EDI module, and the ion content is extremely low. Even after being concentrated by the EDI module, the ion content and hardness of the concentrate chamber are at a relatively safe standard. Similarly, the chloride ion level in the anode chamber will also be reduced, and the risk of oxidation of the anode chamber will be greatly reduced.

[0030] 1. This water inlet method reduces the ion concentration in the concentrate chamber and reduces scaling in the concentrate chamber. It reduces the LSI index in the concentrate chamber, reduces the scaling probability and cleaning times, and can effectively increase the service life of the EDI module.

[0031] 2. Reduce the chloride ion concentration in the anode chamber, reduce the chlorine produced by the anode reaction and dissolve in the water, causing the ion exchange resin filled in the anode chamber to oxidize and cause irreversible damage to the EDI.

[0032] 3. Improve the recovery rate of EDI membrane blocks and the removal rate of weak electrolytes.

[0033] Therefore, the present invention can effectively prolong the service life of the EDI module and reduce energy consumption.

[0034] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a diagram of the working principle of EDI provided in the embodiment of the present application;

[0036] Figure 2 It is a schematic diagram of the prior art waterway provided in the embodiment of the present application;

[0037] Figure 3 This is a schematic diagram of the first waterway of the present application according to an embodiment of the present application;

[0038] Figure 4 A second waterway schematic diagram of the present application is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In order to solve the deficiencies of the prior art, the present invention discloses a continuous electrodeionization (EDI) water inlet system for preventing membrane stack scaling. Figure 3 and 4 As shown, the system of the present invention includes a fresh water chamber, a concentrated water chamber, a fresh water chamber inlet pipe, a fresh water chamber outlet pipe, a concentrated water chamber inlet pipe and a concentrated water chamber outlet pipe, wherein the fresh water chamber inlet pipe is connected to the inlet of the fresh water chamber, the outlet of the fresh water chamber is connected to the fresh water chamber outlet pipe, the concentrated water chamber inlet pipe is connected to the inlet of the concentrated water chamber, and the outlet of the concentrated water chamber is connected to the concentrated water chamber outlet pipe; the fresh water chamber outlet pipe includes a first outlet pipe and a second outlet pipe, the first outlet pipe is connected to the fresh water receiving device; the second outlet pipe is connected to the concentrated water chamber inlet pipe or the concentrated water chamber outlet pipe.

[0041] In some specific embodiments of the present invention, Figure 1 As shown, the EDI module consists of multiple EDI units, each of which is formed by alternating anion exchange membranes and cation exchange membranes, with ion exchange resins filled in between. These units are separated by mesh to form concentrated water chambers and fresh water chambers.

[0042] In order to further improve the system desalination rate and optimize the scaling problem of the EDI device, the present invention changes the external water channel of the EDI module to achieve a lower concentration level of the liquid in the concentrated water chamber. The original secondary reverse osmosis RO effluent was simultaneously supplied to the EDI module fresh water chamber inlet and the concentrated water chamber inlet, and the water supply to the concentrated water chamber was changed to only supply water to the fresh water chamber. The water inlet to the concentrated water chamber was provided by 10% of the flow rate of the produced water. The water inlet direction of the concentrated water chamber was the same as that of the fresh water chamber. Figure 3 The fresh water chamber inlet pipe, the first outlet pipe, the concentrate chamber inlet pipe and the concentrate chamber outlet pipe are all equipped with pressure gauges. When the second outlet pipe is connected to the concentrate chamber inlet pipe, a flow alarm and a flow meter are installed on the concentrate chamber inlet pipe; the flow rate of the concentrate chamber inlet pipe is 0.5m 3 / h;

[0043] The first water outlet pipe is provided with a flow alarm, a flow meter, a resistivity meter and a conductivity meter;

[0044] The flow rate on the first outlet pipe is 5.1m 3 / h;

[0045] The flow ratio between the concentrate chamber inlet pipe and the first outlet pipe is 10:1 to 11:1.

[0046] The water channel design has the following advantages: 1. Protect the membrane block to prevent the membrane block from breaking or over-flow; 2. The flow meter with flow switch has a flow control range of ±10%.

[0047] Since the concentrate chamber is also filled with resin, the conductivity of the resin is several orders of magnitude higher than that of the salt solution, and the conductivity of the concentrate chamber is greatly improved. The resin can quickly migrate the hardness ions on the membrane surface to the main solution - more effective than adding salt (reducing the possibility of scaling). Under this water circuit design, the concentrate and fresh water feed have the same flow direction, and the water flow distribution is more even - no circulation is required. Avoiding scaling does not affect the water production, and it has a protective effect on the concentrate chamber and the electrode chamber. The inlet water of the concentrate chamber is the water produced by the EDI module, and the ion content is extremely low. Even after being concentrated by the EDI module, the ion content and hardness of the concentrate chamber are at a relatively safe standard. Similarly, no chlorine is produced in the anode chamber - there is no need to set up a separate anode water discharge, simplifying the pipeline, and greatly reducing the risk of oxidation of the anode chamber. In the same flow EDI system ( Figure 3 ), the water flow direction is the same as the resin regeneration direction, which usually leads to lower energy consumption, and important parameters such as ion removal rate, resin utilization rate, scaling index, etc. are improved, and the water production rate is also improved.

[0048] In a specific embodiment of the present invention, the present invention also designs a shorter process reverse flow to EDI water inlet mode ( Figure 4), the inlet water of the concentrate chamber is provided by 10% of the flow rate of the produced water, and the inlet direction of the concentrate chamber is opposite to that of the fresh water chamber. At this time, the water flow direction is opposite to the resin regeneration direction, which can improve the ion removal efficiency. Since the product water is directly used as the inlet water of the concentrate, the ion concentration (such as Na + , Ca 2+ Mg 2+ ) will not increase significantly, thus effectively suppressing the scaling trend. At the concentrate outlet, the water hardness reaches its maximum value. Even if the concentration reaches the level of precipitation at this time, the water flow will quickly carry the precipitation out of the EDI, thereby achieving effective treatment of high-hardness water. The choice of EDI system with which flow direction depends on factors such as specific application requirements, water quality requirements, cost budget and space constraints. In actual applications, other factors may also be considered, such as system scalability and ease of operation. Combined with Figure 4 When the second outlet pipe is connected to the outlet pipe of the concentrated water chamber, a flow alarm and a flow meter are provided on the outlet pipe of the concentrated water chamber; the flow rate of the flow meter of the outlet pipe of the concentrated water chamber is 0.4m 3 / h;

[0049] The first outlet pipe is provided with a flow alarm, a flow meter, a resistivity meter and a conductivity meter; the flow rate of the flow meter on the first outlet pipe is 5.1m 3 / h;

[0050] The flow ratio between the concentrate chamber outlet pipe and the first outlet pipe is 10:1 to 11:1.

[0051] The water flow ratio in the first water outlet pipe and the second water outlet pipe is 9:1.

[0052] The present invention also provides a continuous electrodeionization (EDI) water inlet method for preventing membrane stack scaling, using Figure 3 The system shown, the method includes,

[0053] The raw water enters the fresh water chamber through the fresh water chamber inlet pipe for treatment, and then the fresh water is discharged from the outlet of the fresh water chamber; a part of the fresh water enters the fresh water receiving device through the first outlet pipe; the remaining part of the fresh water enters the concentrated water chamber through the second outlet pipe and the concentrated water chamber inlet pipe for treatment to obtain concentrated water, which is discharged through the concentrated water chamber outlet pipe.

[0054] The present invention also provides a continuous electrodeionization (EDI) water inlet method for preventing membrane stack scaling, using Figure 4 The system shown, the method includes,

[0055] After the raw water enters the fresh water chamber through the fresh water chamber inlet pipe for treatment, the fresh water is discharged from the outlet of the fresh water chamber; a part of the fresh water enters the fresh water receiving device through the first outlet pipe; the remaining fresh water enters the concentrated water chamber through the second outlet pipe and the concentrated water chamber outlet pipe for treatment to obtain concentrated water; the concentrated water is discharged through the concentrated water chamber inlet pipe.

[0056] In a specific embodiment of the present invention, the raw water entering the continuous electrodeionization (EDI) is mainly deionized water treated by reverse osmosis (RO) and other purification equipment.

[0057] The fresh water received by the fresh water receiving device is ultrapure water. The ultrapure water prepared by the present invention is mainly used in the fields of electricity, electronics and medicine.

[0058] In a specific embodiment of the present invention, the concentrated water generated by the system of the present application is returned to the water inlet of the reverse osmosis water treatment equipment through a reflux pipe for reuse by the equipment, and a reducing agent (such as sodium sulfite) is added on the way to react, and combined with an online oxidation-reduction potential analyzer (ORP) online detection, the concentrated water is recycled and reused. This method can save raw water, reduce the amount of concentrated water discharged and the cost of sewage discharge, and reduce operating costs.

[0059] The technical solution of the present invention will be further described below in conjunction with specific implementation methods.

[0060] Example 1

[0061] Use Figure 3 The system described above. Set the parameters of the pressure gauges on the fresh water chamber inlet pipe, the first outlet pipe, the concentrate chamber inlet pipe and the concentrate chamber outlet pipe (see Table 1); the flow rate of the flow meter of the fresh water chamber inlet pipe is 5.5m 3 / h; the flow rate of the flow meter on the first outlet pipe is 5.1m 3 / h, the flow rate of the flow meter on the second outlet pipe is 0.4m 3 / h, the flow rate of the flow meter on the second outlet pipe is also the flow rate of the concentrate chamber from the concentrate chamber inlet pipe;

[0062] Turn on the switch on the fresh water chamber inlet pipe, and the water produced after secondary RO purification will enter the EDI module from the fresh water chamber inlet and the concentrated water chamber inlet as raw water. Aquacells membrane block is selected, model: EIMD-50DI (5m 3 / h).

[0063] Example 2

[0064] Use Figure 4 The parameters of the pressure gauges set on the fresh water chamber inlet pipe, the first outlet pipe, the concentrated water chamber inlet pipe and the concentrated water chamber outlet pipe are (see Table 1); the flow rate of the flow meter of the fresh water chamber inlet pipe is 5.5m3 / h; the flow rate of the flow meter on the first outlet pipe is 5.1m 3 / h, the flow rate of the flow meter on the second outlet pipe is 0.4m 3 / h, the flow rate of the flow meter on the second outlet pipe is also the flow rate from the outlet pipe of the concentrate chamber into the concentrate chamber;

[0065] Turn on the switch on the fresh water chamber inlet pipe, and the water produced after secondary RO purification will enter the EDI module from the fresh water chamber inlet and the concentrated water chamber inlet as raw water. Aquacells membrane block is selected, model: EIMD-50DI (5m 3 / h).

[0066] Comparative Example 1

[0067] Use Figure 2 The system described.

[0068] Existing common waterway designs (see Figure 2 ) includes the fresh water chamber inlet, the concentrate chamber inlet, the water outlet, and the concentrate chamber outlet (some water channel designs also include the polar water chamber inlet and the polar water chamber outlet). The produced water after secondary RO purification enters the EDI module from the fresh water chamber inlet and the concentrate chamber inlet as raw water. The water flow distribution ratio is about ten times that of the fresh water chamber to the concentrate chamber. Under this water channel design, the inlet water requirements are as follows: oxide (in terms of Cl2) <0.05mg / L, iron (Fe) <0.01mg / L, manganese (Mn) <0.01mg / L, sulfide <0.01mg / L, total hardness (in terms of CaCO3) <1.0mg / L, dissolved organic matter (TOC, in terms of C) <0.5mg / L, silicon (in terms of SiO2) <1.0mg / L. After the EDI module is in operation, the ions in the raw water are removed from the fresh water chamber and gathered in the concentrated water chamber. The water effluent from the fresh water chamber is produced water (desalted water), and the water effluent from the concentrated water chamber is concentrated water with a higher ion concentration.

[0069] Anode reaction: 2Cl - →Cl2-2e - ;

[0070] Cathode reaction: 2H2O+2e - →2OH - +H2;

[0071] The oxidation reaction at the anode produces O2 and Cl2, and the reduction reaction at the cathode produces H2. Since the influent contains residual chlorine, the chlorine gas generated by the reaction will physically dissolve in the anode liquid in the anode reaction and exist in the solution in the form of active chlorine, Cl2(g)=Cl2(aq). The chlorine gas dissolved in the water acts as an oxidant, which will destroy the cross-linking of the ion exchange resin, thereby destroying the internal structure of the resin and affecting the service life of the EDI module. It should be noted that the quality of the concentrated water is inferior to that of the raw water (i.e. the produced water after secondary RO purification), and the chloride ions must be removed before it can be recycled.

[0072] The parameters of the pressure gauges set on the fresh water chamber inlet pipe, the first outlet pipe, the concentrate chamber inlet pipe and the concentrate chamber outlet pipe are (see Table 1, reference data); the flow meter of the concentrate chamber inlet pipe is 0.5m 3 / h; the flow meter on the first outlet pipe is 5.0m 3 / h.

[0073] Table 1: Figure 3 (same direction) and Figure 2 Implementation data comparison

[0074]

[0075] The experimental data are shown in Table 2.

[0076] Table 2 Comparison of technical parameters and usage results:

[0077]

[0078] According to Table 1-2, compared with the prior art, the water inlet method of the present invention can effectively reduce the ion concentration in the concentrate chamber and reduce the scaling in the concentrate chamber; increase the removal rate of weak electrolytic ions by 5%; reduce the LSI index of the concentrate chamber, reduce the scaling probability and the number of cleaning times. At the same time, the chloride ion concentration in the anode chamber is reduced, and the chlorine produced by the anode reaction is reduced. The chlorine gas dissolved in the water causes the ion exchange resin filled in the anode chamber to be oxidized, resulting in irreversible damage to the EDI; the recovery rate of the EDI membrane block is improved, and the removal rate of weak electrolytes is improved.

[0079] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous electrodeionization water inlet system for preventing membrane stack scaling, characterized in that: The system comprises a fresh water chamber, a concentrated water chamber, a fresh water chamber water inlet pipe, a fresh water chamber water outlet pipe, a concentrated water chamber water inlet pipe and a concentrated water chamber water outlet pipe, wherein: The fresh water chamber inlet pipe is connected to the fresh water chamber inlet, the fresh water chamber outlet is connected to the fresh water chamber outlet pipe, the concentrated water chamber inlet pipe is connected to the concentrated water chamber inlet, and the concentrated water chamber outlet is connected to the concentrated water chamber outlet pipe; The fresh water chamber outlet pipe comprises a first outlet pipe and a second outlet pipe, wherein the first outlet pipe is connected to the fresh water receiving device; The second water outlet pipe is connected to the concentrated water chamber water inlet pipe or the concentrated water chamber water outlet pipe.

2. The continuous electrodeionization water inlet system for preventing membrane stack scaling according to claim 1 is characterized in that: Pressure gauges are provided on the fresh water chamber inlet pipe, the first outlet pipe, the concentrated water chamber inlet pipe and the concentrated water chamber outlet pipe.

3. The continuous electrodeionization water inlet system for preventing membrane stack scaling according to claim 2 is characterized in that: When the second water outlet pipe is connected to the concentrated water chamber water inlet pipe, a flow alarm and a flow meter are provided on the concentrated water chamber water inlet pipe.

4. The continuous electrodeionization water inlet system for preventing membrane stack scaling according to claim 2 is characterized in that: When the second water outlet pipe is connected to the concentrated water chamber water outlet pipe, a flow alarm and a flow meter are provided on the concentrated water chamber water outlet pipe.

5. The continuous electrodeionization water inlet system for preventing membrane stack scaling according to any one of claims 1 to 4, characterized in that: The first water outlet pipe is provided with a flow alarm, a flow meter, a resistivity meter and a conductivity meter.

6. A continuous electrodeionization water inlet method for preventing membrane stack scaling, characterized in that: Using the system according to any one of claims 1 to 5, the method comprises: After the raw water enters the fresh water chamber through the fresh water chamber inlet pipe and is treated, the fresh water is discharged from the fresh water chamber outlet; A portion of the fresh water enters the fresh water receiving device through the first water outlet pipe; The remaining fresh water enters the concentrated water chamber through the second outlet pipe.

7. The continuous electrodeionization (EDI) water inlet method for preventing membrane stack scaling according to claim 6, characterized in that: The remaining fresh water enters the concentrated water chamber through the second outlet pipe, including: The remaining fresh water passes through the second outlet pipe, the concentrate chamber inlet pipe, and the concentrate chamber inlet and enters the concentrate chamber for treatment to obtain concentrate. The concentrated water is discharged through the concentrated water chamber outlet and the concentrated water chamber outlet pipe.

8. The continuous electrodeionization (EDI) water inlet method for preventing membrane stack scaling according to claim 6, characterized in that: The remaining fresh water enters the concentrated water chamber through the second outlet pipe, including: The remaining fresh water passes through the second outlet pipe, the outlet pipe of the concentrate chamber, and the outlet of the concentrate chamber and enters the concentrate chamber for treatment to obtain concentrate; The concentrated water is discharged through the concentrated water chamber water inlet and the concentrated water chamber water inlet pipe.

9. The continuous electrodeionization water inlet method for preventing membrane stack scaling according to any one of claims 6 to 8, characterized in that: The flow rate of the fresh water chamber inlet pipe is 105%-110% of the standard water output of the membrane stack.

10. The continuous electrodeionization water inlet method for preventing membrane stack scaling according to any one of claims 6 to 8, characterized in that: The fresh water flow ratio in the first outlet pipe and the second outlet pipe is 10:1 to 11:1.

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