Electrically-driven membrane desalting device and operation method thereof

Abstract

The invention relates to the technical field of electrically-driven membrane desalting devices, and provides an electrically-driven membrane desalting device and an operation method thereof.The electrically-driven membrane desalting device comprises a pipe frame and further comprises a membrane stack installed on the right side of the pipe frame, a plurality of ion exchange membranes arranged in parallel are stacked in the middle of the membrane stack, and a plurality of water distribution pipes and water collection pipes are arranged on the upper portion and the lower portion of each ion exchange membrane at equal intervals; the ion exchange membranes comprise cation membranes and anion membranes which are alternately arranged, desalination chambers and concentration chambers which are alternately distributed are formed between the adjacent ion exchange membranes, cathode chambers and anode chambers are respectively arranged on the outermost sides of the left and right sides of the membrane stack, auxiliary nets are attached to the main surfaces of the two sides of each ion exchange membrane, and salient point bags are arranged on the outer surfaces of the auxiliary nets in an equidistant and crossed manner; the pipe conveying assembly is installed in the middle of the pipe frame. When the device is used, a bubble cleaning mechanism is utilized to reduce the scaling amount of calcium and magnesium ions on the membrane surface, the membrane holes are prevented from being blocked, the permeability of the ion exchange membrane is maintained, and the desalting efficiency of the electrically driven membrane desalting device is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of electro-driven membrane desalination devices, and more specifically, to an electro-driven membrane desalination device and an operation method thereof. Background Art

[0002] Electro-driven membrane desalination technology is a water treatment technology that realizes the selective separation of ions based on the action of an electric field. Its core is to utilize the selective permeability characteristics of ion exchange membranes and combine the direct current electric field to drive the migration of ions, thereby achieving the removal or concentration of salts in the solution.

[0003] The comparative document (publication number: CN101690869A, classification number: B01D61 / 58) discloses that the brine to be discharged from the electro-dialysis concentration chamber generates reverse osmosis fresh water through the action of reverse osmosis. Among them, electro-dialysis concentration is the electro-driven membrane desalination technology.

[0004] Under the drive of a direct current electric field, multivalent calcium and magnesium ions, due to their high charge density and slow migration rate, are prone to form a concentration enrichment on the surface of the ion exchange membrane. At the same time, the water electrolysis effect caused by the electric field will lead to local pH imbalance at the membrane interface, prompting calcium and magnesium ions to combine with functional groups such as sulfonic acid groups and quaternary ammonium groups on the membrane surface, or react with carbonate ions and hydroxide ions in the water to form insoluble salts such as CaCO3 and Mg(OH)2.

[0005] In the above process, high-concentration calcium and magnesium ions will cause membrane pore blockage and the covering of active sites, hindering the adsorption and diffusion of target ions. At the same time, the scaling layer increases the mass transfer resistance at the membrane-liquid interface, exacerbates the vicious cycle of local concentration polarization and membrane fouling, and multivalent ions compete with monovalent target ions for migration, ultimately reducing the membrane separation efficiency and resulting in a decrease in the desalination rate.

[0006] Therefore, the present application proposes an electro-driven membrane desalination device and an operation method thereof to solve the above problems. Summary of the Invention

[0007] Technical problems to be solved: Aiming at the problems existing in the prior art, the purpose of the present invention is to provide an electro-driven membrane desalination device and an operation method thereof, which solve the problems that the membrane pore blockage and the covering of active sites of the ion exchange membrane caused by scaling of high-concentration calcium and magnesium ions in the prior art, resulting in the inability to maintain the ion exchange and permeability performance of the ion exchange membrane, and the decrease in the desalination efficiency of the electro-driven membrane desalination device.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: An electric-driven membrane desalination device includes a pipe rack, and further includes: A membrane stack installed on the right side of the pipe rack, with multiple ion exchange membranes stacked in parallel in the middle, and a plurality of water distribution pipes and water collection pipes are arranged at equal intervals on the upper and lower parts of the ion exchange membranes respectively; The ion exchange membranes include alternately arranged cation membranes and anion membranes, and the adjacent ion exchange membranes form alternately distributed desalination chambers and concentration chambers. The outermost sides on the left and right of the membrane stack are the cathode chamber and the anode chamber respectively. Under the direct current electric field, ions migrate through the corresponding membranes to achieve directional separation of salts. Auxiliary nets are attached to both main surfaces on both sides of the ion exchange membranes, and bump packages are arranged in an equidistant cross pattern on the outer surface of the auxiliary nets; A pipe transportation component installed in the middle of the pipe rack, used to transport the original liquid to the desalination chamber and concentration chamber of the membrane stack for circulation, and to transport the electrode water to the anode chamber and cathode chamber; A bubble component installed at the bottom of the membrane stack, used to provide microbubbles in the original liquid transported in the water distribution pipes at the lower part of the membrane stack; An annular air pipe is installed at the water inlet of the water distribution pipe, and a plurality of exhaust ports are equidistantly opened on the inner wall of the annular air pipe. One-way waterproof breathable membranes are installed in the exhaust ports, a plurality of dialysis holes are equidistantly opened on the water distribution pipe, and a plurality of spiral fin rings are equidistantly installed on the inner wall of the water distribution pipe.

[0009] In a new embodiment, the outer surface of the bump package is distributed with a rough burr surface, and a hydrophobic material is applied on the bump package; The hydrophobic material is polytetrafluoroethylene or a silane-modified coating, and the coating thickness is 10 - 50 μm.

[0010] In a new embodiment, a partition net is arranged between two adjacent ion exchange membranes, and a carbon electrode material is embedded in the partition net.

[0011] In a new embodiment, a liquid infusion pipe group is arranged at the lower part of one side of the membrane stack. The liquid infusion pipe group includes alternately arranged fresh water inlet pipes and concentrated water inlet pipes, and both are connected to the water inlet of the corresponding water distribution pipe; A liquid discharge pipe group is arranged at the upper part of the same side of the membrane stack. The liquid discharge pipe group includes alternately arranged fresh water discharge pipes and concentrated water discharge pipes, and both are connected to the water outlet of the corresponding water collection pipe.

[0012] In a new embodiment, the pipeline transportation assembly includes: three tanks, all located at the rear of the pipe rack, which are the fresh water tank, the concentrated water tank, and the polar water tank from left to right in sequence; three conveying pumps, which are equidistantly installed at the bottom of the pipe rack; the water outlets of the fresh water tank and the concentrated water tank are respectively communicated with the water inlet ends of the corresponding conveying pumps through pipelines, the drainage ends of the conveying pumps located on the left and middle of the bottom of the pipe rack are communicated with the liquid conveying pipe group at the lower part of the membrane stack through pipelines, and the liquids discharged from the liquid discharge pipe group at the upper part of the membrane stack flow into the connected fresh water tank and concentrated water tank respectively through the reflux pipeline; the water outlet of the polar water tank is communicated with the water inlet end of the corresponding conveying pump through a pipeline, the water outlet end of the conveying pump located on the right side of the bottom of the pipe rack is communicated with the liquid inlet ports of the cathode chamber and the anode chamber of the membrane stack through a pipeline, and the liquid outlet ports of the cathode chamber and the anode chamber flow into the connected polar water tank through the reflux pipeline.

[0013] In a new embodiment, the bubble assembly includes: a locking frame, installed at the bottom of the membrane stack; a microbubble generator, installed at the bottom of the locking frame; a shunt cross pipe is installed at the air outlet of the microbubble generator, and one side of the shunt cross pipe facing inwards is respectively connected with one ends of a plurality of branch discharge pipes arranged at equal intervals, and the other ends of the branch discharge pipes are connected with the air inlet of the annular air pipe in the water inlet of the water distribution pipe.

[0014] In a new embodiment, side branch discharge pipes are installed on the reflux pipelines where the fresh water discharge pipe and the concentrated water discharge pipe are connected, and solenoid valves are installed on the side branch discharge pipes.

[0015] In a new embodiment, a control cabinet is installed on the left side of the pipe rack, and the control cabinet is electrically connected to the three conveying pumps, the microbubble generator, and the solenoid valves on the side branch discharge pipes.

[0016] An operation method of an electric-driven membrane desalination device includes the following steps: S1. Pump the raw water in the fresh water tank into the desalination chamber of the membrane stack through a conveying pump, pump the concentrated water circulating liquid in the concentrated water tank into the concentration chamber, pump the polar water in the polar water tank into the cathode chamber and the anode chamber at both ends of the membrane stack, apply a direct current electric field, cations migrate to the cathode and pass through the cation exchange membrane into the concentration chamber, anions migrate to the anode and pass through the anion exchange membrane into the concentration chamber, realizing the directional transfer of salts from the desalination chamber to the concentration chamber. The fresh water and concentrated water after the first separation are respectively refluxed to the fresh water tank and the concentrated water tank, and the cycle treatment is repeated until the fresh water produced in the desalination chamber meets the standard and is discharged for collection, and the concentrated water produced in the concentration chamber is enriched to the set concentration and then collected; S2. When membrane stack cleaning is required, start the bubble component to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe, the spiral guiding effect of the spiral fin ring on the inner wall of the water distribution pipe forces the fluid to rotate, generating a centrifugal force to break the bubbles into smaller particle sizes. At the same time, the microdialysis hole microarray on the water distribution pipe further cuts the bubbles to form a uniform microbubble group. The microbubble group contacts and breaks with the convex point packages arranged crosswise on the outer surface of the auxiliary net on the surface of the ion exchange membrane with the water flow, generating local microjets to impact and peel off the calcium and magnesium ion scale initially deposited on the membrane surface; S3. The peeled calcium and magnesium ion scale particles settle to the water collecting pipe at the bottom of the membrane stack with the water flow, and are transported to the side branch drain pipe through the drain pipe group and the return pipeline. The low-salt wastewater and calcium and magnesium scale particles in the desalination chamber, and the high-salt wastewater and calcium and magnesium scale particles in the concentration chamber are discharged through the side branch drain pipe and collected and treated externally.

[0017] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows: 1. In the process of cleaning the ion exchange membrane, the bubbles generated by the bubble component are broken into smaller particle sizes and form a rotating gas-liquid mixed flow through the synergistic action of the annular gas pipe, the spiral fin ring and the dialysis holes. The microbubbles impact the convex point packages on the surface of the auxiliary net with the water flow and break, generating local microjets to precisely peel off the calcium and magnesium ion scale initially formed on the surface of the ion exchange membrane, avoiding membrane pore blockage, maintaining the permeability and desalination efficiency of the ion exchange membrane. This process uses hydrogen or air microbubbles generated by electrolysis, and there is no secondary pollution after rupture, with significant cleaning effect and environmental protection.

[0018] 2. The spiral fin ring on the inner wall of the water distribution pipe forces the gas-liquid flow to rotate, using the centrifugal force to break the bubbles into smaller particle sizes, and cooperating with the microarray of dialysis holes at the bottom to further cut the bubbles to form a uniform microbubble group. The rotating flow drives the microbubbles to impact the membrane surface in the direction of the dialysis hole penetration, enhancing the uniformity of bubble rupture and the efficiency of scale peeling.

[0019] 3. A one-way waterproof and breathable membrane is arranged in the exhaust port of the annular gas pipe at the water inlet of the water distribution pipe. Its selective permeation characteristic only allows microbubbles to be released into the water distribution pipe, preventing the reverse penetration of fresh water, concentrated water or extreme water, and avoiding the failure of the bubble component or pipeline corrosion caused by liquid backflow.

[0020] 4. On the auxiliary nets attached to both sides of the ion exchange membrane, convex point packages are arranged crosswise at equal distances. The rough and burr surface of its surface can reduce the energy required for bubble rupture, making it easier for microbubbles to break at the convex point packages, generating dense microjets. At the same time, the convex point packages are coated with a polytetrafluoroethylene or silane-modified hydrophobic coating, which can block the ion enrichment environment required for scale nucleation, reduce scale adhesion. In addition, the convex point packages are small in volume and distributed dispersedly, which neither affects the core function of the ion exchange membrane nor can accurately strike the scale area through the tip effect, realizing low-energy and high-efficiency scale prevention.

[0021] 5. The pipeline transportation component realizes the directional transportation and recycling of the raw liquid, concentrated water, and extreme water through the circulating pipelines of the fresh water tank, concentrated water tank, extreme water tank, and transfer pump. The side branch drain pipe collects the low-salt wastewater from the desalination chamber, the high-salt wastewater from the concentration chamber, and the stripped calcium and magnesium ion scaling particles, avoiding the blockage of membrane pores and the pollution of flow channels caused by scaling accumulation, and realizing the hierarchical treatment of wastewater and the improvement of the anti-pollution ability of the membrane stack. Description of the Drawings

[0022] Figure 1 It is a three-dimensional structure schematic diagram of the present invention.

[0023] Figure 2 It is a three-dimensional structure schematic diagram of another perspective of the present invention.

[0024] Figure 3 It is a schematic diagram of the position structure of the tank body of the present invention.

[0025] Figure 4 It is a schematic diagram of the pipeline transportation component structure of the present invention.

[0026] Figure 5 It is a schematic diagram of the membrane stack structure of the present invention.

[0027] Figure 6 It is a schematic diagram of the intercepting component structure of the present invention.

[0028] Figure 7 It is a schematic diagram of the bubble component structure of the present invention.

[0029] Figure 8 It is a schematic diagram of the installation position structure of the water distribution pipe of the present invention.

[0030] Figure 9 It is a schematic diagram of the internal structure of the water distribution pipe of the present invention.

[0031] Figure 10 It is a schematic diagram of the annular air pipe structure of the present invention.

[0032] Figure 11 It is a schematic diagram of the position structure of the spiral fin ring of the present invention.

[0033] Figure 12 It is a schematic diagram of the ion exchange membrane structure of the present invention.

[0034] Figure 13 It is a schematic diagram of the disassembled structure of the ion exchange membrane of the present invention.

[0035] Figure 14 It is a schematic diagram of the partition net structure of the present invention.

[0036] Figure 15 For the present invention Figure 12 Enlarged view of the structure at point A.

[0037] Figure 16 Schematic diagram of the influence area of the broken bubbles of the bump package of the present invention.

[0038] In the figure, the reference numerals are: 1, pipe rack; 2, membrane stack; 21, ion exchange membrane; 211, auxiliary net; 212, bump package; 213, rough burr surface; 214, hydrophobic material; 215, partition net; 216, carbon electrode material; 22, water distribution pipe; 23, water collection pipe; 24, annular gas pipe; 25, exhaust port; 26, dialysis hole; 27, spiral fin ring; 28, infusion pipe group; 281, fresh water inlet pipe; 282, concentrated water inlet pipe; 29, liquid discharge pipe group; 291, fresh water discharge pipe; 292, concentrated water discharge pipe; 3, pipe transportation assembly; 300, tank body; 301, fresh water tank; 302, concentrated water tank; 303, electrode water tank; 304, transfer pump; 305, return pipeline; 4, bubble assembly; 401, locking frame; 402, microbubble generator; 403, shunt cross pipe; 404, branch discharge pipe; 5, side branch discharge pipe; 6, control cabinet. Specific embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] By providing an electric-driven membrane desalination device and its operation method in the embodiments of the present application, the problems of membrane pore blockage and active site coverage of the ion exchange membrane caused by scaling of high-concentration calcium and magnesium ions in the prior art are solved, resulting in the inability to maintain the ion exchange permeability of the ion exchange membrane and the decline of the desalination efficiency of the electric-driven membrane desalination device. During use, the bubble cleaning mechanism is used to reduce the amount of calcium and magnesium ion scaling on the membrane surface, avoid membrane pore blockage, maintain the permeability of the ion exchange membrane, and ensure the desalination efficiency of the electric-driven membrane desalination device.

[0041] The technical solutions in the embodiments of the present application are as follows to solve the above technical problems.

[0042] Example 1, please refer to Figures 1 - 16, an embodiment of the present application provides an electric-driven membrane desalination device, including a pipe rack 1, and further including: a membrane stack 2, installed on the right side of the pipe rack 1, in which a plurality of ion exchange membranes 21 arranged in parallel are stacked in the middle, and a plurality of water distribution pipes 22 and water collection pipes 23 are arranged at equal intervals on the upper and lower parts of the ion exchange membrane 21 respectively; the ion exchange membrane 21 includes alternately arranged cation membranes and anion membranes, and alternately distributed desalination chambers and concentration chambers are formed between adjacent ion exchange membranes 21. The outermost sides on the left and right of the membrane stack 2 are the cathode chamber and the anode chamber respectively. Under the direct current electric field, ions migrate through the corresponding membranes to achieve directional separation of salts. Auxiliary nets 211 are attached to both main surfaces of the ion exchange membrane 21, and bump packages 212 are arranged at equal intervals and crosswise on the outer surface of the auxiliary net 211; a pipe conveying assembly 3, installed in the middle of the pipe rack 1, is used to convey the raw liquid to the desalination chamber and the concentration chamber of the membrane stack 2 for circulation, and to convey the electrode water to the anode chamber and the cathode chamber; a bubble assembly 4, installed at the bottom of the membrane stack 2, is used to provide microbubbles in the raw liquid conveyed in the lower water distribution pipe 22 of the membrane stack 2; an annular air pipe 24 is installed at the water inlet of the water distribution pipe 22, and a plurality of exhaust ports 25 are equidistantly arranged on the inner wall of the annular air pipe 24. One-way waterproof and breathable membranes are installed in the exhaust ports 25, and a plurality of dialysis holes 26 are equidistantly arranged on the water distribution pipe 22, and a plurality of spiral fin rings 27 are equidistantly installed on the inner wall of the water distribution pipe 22.

[0043] In this embodiment, please refer to Figures 1 - 16 As shown, the ion exchange membrane 21 is alternately arranged with cation membranes and anion membranes to form a periodic arrangement of desalination chambers and concentration chambers. Under the action of an electric field, cations in water can be driven to migrate to the cathode through the cation membrane, and anions can migrate to the anode through the anion membrane, so that the ion concentration in the desalination chamber can be rapidly reduced, and ions in the concentration chamber can be efficiently enriched, significantly improving the salt separation efficiency and meeting the requirements for the preparation of high-purity fresh water.

[0044] During the electric-driven membrane water treatment process, calcium and magnesium ions are easily attached to the two main surfaces of the cation membrane and the anion membrane of the ion exchange membrane 21 due to the action of the electric field and scale formation occurs. It is difficult to effectively clean by traditional methods. Therefore, the present technology uses a dual mechanism of regular integrated microbubble generation and surface structure optimization of the ion exchange membrane 21 to clean the scaling state of calcium and magnesium ions on the two main surfaces of the ion exchange membrane 21 in a microbubble manner, keeping the membrane surface of the ion exchange membrane 21 from being blocked, ensuring the normal progress of the ion exchange operation of the ion exchange membrane 21, and maintaining the desalination efficiency.

[0045] By setting up the water distribution pipe 22, the annular air pipe 24, the exhaust port 25, the one-way waterproof and breathable membrane, the dialysis holes 26, and the spiral fin ring 27, first, the bubble assembly 4 generates micron-sized bubbles through the electrolysis of water technology and transports them to the connected annular air pipe 24. The annular air pipe 24 discharges the bubbles to the water inlet of the water distribution pipe 22 through the annularly distributed exhaust ports 25 on the inner wall, and enters the pipe part of the water distribution pipe 22 buried in the membrane stack 2 along with the liquid flowing into the water distribution pipe 22. And with the inflow of the liquid and the bubbles, it will also contact the spiral fin ring 27 in the water distribution pipe 22 to form a gas-liquid mixed flow. The water distribution pipe 22 forces the gas-liquid flow to rotate, generating a flow centrifugal force to break the bubbles into smaller particle sizes, and discharging them through the dialysis holes 26 of the microporous array at the bottom of the water distribution pipe 22. The rotating flow drives the micro-bubbles to impact the two main surfaces of the ion exchange membrane 21 along the penetration and falling direction of the dialysis holes 26, and contacts and breaks the bump packages 212 on the auxiliary net 211 attached to the two surfaces of the ion exchange membrane 21, generating a micro-jet to strip the calcium and magnesium ion scale on the ion exchange membrane 21 and the auxiliary net 211.

[0046] It should be noted that the one-way waterproof and breathable membrane in the exhaust port 25 has a selective permeation characteristic, allowing the micro-bubbles to be released into the liquid flowing from the exhaust port 25 to the water inlet of the water distribution pipe 22, preventing the reverse osmosis of fresh water and concentrated water into the annular air pipe 24, avoiding the failure of the bubble assembly 4 or pipeline corrosion caused by liquid backflow, and the porosity and surface tension of the membrane material of the one-way breathable and waterproof net can withstand a large water-side pressure, ensuring the sealing of the bubble path during the operation of the device and maintaining a stable bubble generation efficiency.

[0047] In terms of optimizing the surface structure of the ion exchange membrane 21, an auxiliary net 211 is attached to the two main surfaces of the ion exchange membrane 21. The bump packages 212 arranged at equal intervals and crosswise on the auxiliary net 211, and the micro-bubbles released through the dialysis holes 26 of the water distribution pipe 22 contact the bump packages 212 on the auxiliary net 211 on the two main surfaces of the ion exchange membrane 21 along with the liquid flow. The bump packages 212 are like the tips of needles. When the micro-bubbles contact the bump packages 212, they will burst with a "pop", and a very tiny water flow micro-jet will be generated when they burst. Figure 16 In the shaded area of the reference

[0048] Further, please refer to Figure 13 and Figure 14, a partition net 215 is arranged between two adjacent ion exchange membranes 21, and a carbon electrode material 216 is embedded in the partition net 215.

[0049] There is a partition net 215 between two adjacent ion exchange membranes 21. As a spacer support for the ion exchange membrane 21, it maintains an equal-distance parallel arrangement of adjacent membranes, avoiding the blockage of the flow channel caused by the membrane sheets fitting together, ensuring the stability of the desalination chamber and the concentration chamber. The carbon electrode material 216 embedded in the partition net 215, such as activated carbon and carbon fiber, serves as a local conductive medium to form an independent conductive unit between two adjacent ion exchange membranes 21. Collaborating with the main electrodes cathode / anode at both ends of the membrane stack 2, a multi-stage electric field network is constructed. The local electric field enables the migration distance of ions from the desalination chamber to the concentration chamber to change from depending on the overall electric field of the membrane stack 2 to depending on the micro-electric field of adjacent electrodes, reducing the migration resistance and improving the separation efficiency. It should be noted that the types of the partition net 215 are divided into the electrode water partition, the fresh water partition, and the concentrated water partition. The following is the arrangement order of the ion exchange membrane 21 and the partition net 215: anode plate → electrode water partition → cationic membrane → fresh water partition → anionic membrane → concentrated water partition →... → cathode plate.

[0050] Further, please refer to Figure 13 and Figure 15 , the outer surface of the bump package 212 is distributed with a rough burr surface 213, and a hydrophobic material 214 is coated on the bump package 212; the hydrophobic material 214 is polytetrafluoroethylene or a silane-modified coating, and the coating thickness is 10 - 50 μm.

[0051] By setting the rough burr surface 213 and the hydrophobic material 214, the rough burr surface 213 on the surface of the bump package 212 forms dense bubble rupture sites by increasing the microscopic roughness of the membrane surface. When the micro-bubbles flow with the water flow and contact the bump package 212, the burrs on the rough surface can significantly reduce the energy required for bubble rupture, making the micro-bubbles more likely to break at the bump package 212. The generated micro-jet can precisely act on the calcium and magnesium ion scale deposits such as CaCO3 and Mg(OH)2 microcrystals initially formed on the surface of the ion exchange membrane 21, and peel them off from the membrane surface by the impact force, preventing the further growth and thickening of the scale layer. At the same time, the hydrophobic material 214 coated on the bump package 212 has the characteristic of low surface energy, similar to the coating of a non-stick pan, making it difficult for scale to adhere to the bump package 212, blocking the ion enrichment environment required for scale nucleation, keeping the bump package 212 clean, and the bump package 212 is located on the auxiliary net 211, with a small volume and cross-dispersed positions, which neither affects the main function of ion exchange of the ion exchange membrane 21 nor requires complex improvement of the ion exchange membrane 21. Only the auxiliary net 211 needs to be added to its two main surfaces. It should be noted that the auxiliary net 211 does not affect the ion exchange operation of the ion exchange membrane 21.

[0052] Further, please refer toFigures 7 - 9 , a liquid infusion pipe group 28 is arranged at the lower part of one side of the membrane stack 2. The liquid infusion pipe group 28 includes a fresh water inlet pipe 281 and a concentrated water inlet pipe 282 which are arranged alternately, and both are communicated with the water inlet of the corresponding water distribution pipe 22; a liquid discharge pipe group 29 is arranged at the upper part of the same side of the membrane stack 2. The liquid discharge pipe group 29 includes a fresh water discharge pipe 291 and a concentrated water discharge pipe 292 which are arranged alternately, and both are communicated with the water outlet of the corresponding water collection pipe 23.

[0053] The liquid infusion pipe group 28 includes a fresh water inlet pipe 281 and a concentrated water inlet pipe 282, which provide fresh water and concentrated water injection interfaces for the water distribution pipe 22 on the membrane stack 2; the liquid discharge pipe group 29 includes a fresh water discharge pipe 291 and a concentrated water discharge pipe 292, which provide fresh water and concentrated water discharge interfaces for the water collection pipe 23 on the membrane stack 2.

[0054] Further, please refer to Figures 5 - 9 , the bubble assembly 4 includes: a locking frame 401, which is installed at the bottom of the membrane stack 2; a micro-bubble generator 402, which is installed at the bottom of the locking frame 401; a shunt cross pipe 403 is installed at the air outlet of the micro-bubble generator 402. One side of the shunt cross pipe 403 facing inwards is communicated with one end of a plurality of branch drain pipes 404 arranged at equal intervals. The other end of the branch drain pipe 404 is communicated with the air inlet of an annular air pipe 24 located in the water inlet of the water distribution pipe 22.

[0055] Through the locking frame 401, the micro-bubble generator 402, the shunt cross pipe 403 and the branch drain pipes 404, the locking frame 401 is fixed to the bottom of the membrane stack 2, providing a stable installation foundation for the micro-bubble generator 402. The micro-bubbles generated when the micro-bubble generator 402 operates enter the shunt cross pipe 403 through the air outlet, and the bubbles are evenly distributed to each branch drain pipe 404 arranged at equal intervals through its internal flow channel. The end of each branch drain pipe 404 is communicated with the air inlet of the annular air pipe 24 in the water inlet of the water distribution pipe 22. The bubbles are further evenly dispersed through the annular air distribution structure of the annular air pipe 24, and finally enter the flow channels of the desalination chamber and the concentration chamber of the membrane stack 2 synchronously with the water to be treated for subsequent bubble cleaning operations.

[0056] Further, please refer to Figures 1 - 9, the pipeline transportation assembly 3 includes: three tanks 300, all located at the rear of the pipe rack 1, which are the fresh water tank 301, the concentrated water tank 302, and the polar water tank 303 from left to right in sequence; three transfer pumps 304, which are equidistantly installed at the bottom of the pipe rack 1; the water outlets of the fresh water tank 301 and the concentrated water tank 302 are both connected to the water inlet ends of the corresponding transfer pumps 304 through pipelines, and the water discharge ends of the transfer pumps 304 located on the left side and the middle at the bottom of the pipe rack 1 are connected to the liquid delivery pipe group 28 at the lower part of the membrane stack 2 through pipelines. The liquid discharged from the liquid discharge pipe group 29 at the upper part of the membrane stack 2 flows into the connected fresh water tank 301 and concentrated water tank 302 respectively through the return pipeline 305; the water outlet of the polar water tank 303 is connected to the water inlet end of the corresponding transfer pump 304 through a pipeline, and the water outlet end of the transfer pump 304 located on the right side at the bottom of the pipe rack 1 is connected to the liquid inlet ports of the cathode chamber and the anode chamber of the membrane stack 2 through a pipeline, and the liquid outlet ports of the cathode chamber and the anode chamber flow into the connected polar water tank 303 through the return pipeline 305.

[0057] The fresh water tank 301, the concentrated water tank 302, and the polar water tank 303 store the saline water to be treated, the circulating concentrated water, and the polar water respectively. The three transfer pumps 304 are connected to the corresponding tanks 300 to provide power for the transportation of the liquid. The transfer pump 304 connects the original liquid in the concentrated water tank 302 and the fresh water tank 301 to the liquid delivery pipe group 28 through pipelines, and then pumps it into the concentration chamber and the desalination chamber of the membrane stack 2. The liquid discharged from the concentration chamber and the desalination chamber then flows back into the concentrated water tank 302 and the fresh water tank 301 through the return pipeline 305. In this way, the salt in the water is reduced through circulation. Finally, the treated liquid discharged from the concentration chamber and the desalination chamber is collected through the discharge pipeline (not shown in the figure). Among them, the polar water tank 303 also transports the polar water to the cathode chamber and the anode chamber of the membrane stack 2 through the transfer pump 304 to supplement the polar water inside the two, and can also be recycled or recovered with the cooperation of the return pipeline 305.

[0058] Further, please refer to Figure 6 , solenoid valves are installed on the side branch drain pipes 5 which are installed on the return pipeline 305 where the fresh water drain pipe 291 and the concentrated water drain pipe 292 are connected.

[0059] By setting up the side branch drain pipe 5, the scaly calcium and magnesium ion particles attached to the surface of the ion exchange membrane 21 are stripped into a suspended state by the scouring effect of microbubbles and flow to the water collecting pipe 23 with the water flow and are discharged. They are discharged into the side branch drain pipe 5 of the opened solenoid valve through the drain pipe group 29 communicated with the water collecting pipe 23 and the return pipeline 305 communicated with the drain pipe group 29, and are collected by external discharge through the side branch drain pipe 5. Thus, the wastewater discharged from the desalination chamber and the concentration chamber and the stripped scaly calcium and magnesium ion particles are separately collected. This process avoids the membrane pore blockage and the decline of the separation efficiency caused by the long-term attachment of scale through the synergistic effect of microbubble scouring and the side branch drain pipe 5, realizes the directional interception and discharge of the scale particles, the hierarchical treatment of the wastewater, and the anti-blockage of the flow channels of the membrane stack 2, and improves the anti-pollution ability and separation efficiency of the membrane module.

[0060] Further, please refer to Figures 1 - 4 , a control cabinet 6 is installed on the left side of the pipe rack 1. The control cabinet 6 is electrically connected to the three delivery pumps 304, the microbubble generator 402, and the solenoid valve on the side branch drain pipe 5. By using the control cabinet 6, it is convenient to monitor the working states of the three delivery pumps 304, the microbubble generator 402, and the solenoid valve on the side branch drain pipe 5 in real time, and separate control and opening can be carried out. For example, when the stripping operation of the calcium and magnesium ion scale on the membrane stack 2 is required, the microbubble generator 402 and the solenoid valve on the side branch drain pipe 5 are opened. While carrying out the cleaning by the bubble mechanism, the discharged wastewater and impurities can also be collected.

[0061] Embodiment 2, please refer to Figures 1 - 16 , this embodiment of the present application also provides an operation method for an electric-driven membrane desalination device, including the following steps: S1. The raw water in the fresh water tank 301 is pumped into the desalination chamber of the membrane stack 2 through the delivery pump 304, the concentrated water circulation liquid in the concentrated water tank 302 is pumped into the concentration chamber, and the electrode water in the electrode water tank 303 is pumped into the cathode chamber and the anode chamber at both ends of the membrane stack 2. A direct current electric field is applied. Cations migrate to the cathode and pass through the cation exchange membrane into the concentration chamber, and anions migrate to the anode and pass through the anion exchange membrane into the concentration chamber, realizing the directional transfer of salts from the desalination chamber to the concentration chamber. The fresh water and the concentrated water after the first separation are respectively returned to the fresh water tank 301 and the concentrated water tank 302, and the cycle treatment is repeated until the fresh water produced in the desalination chamber meets the standard and is discharged and collected, and the concentrated water produced in the concentration chamber is enriched to the set concentration and then collected; S2. When the membrane stack 2 needs to be cleaned, start the bubble component 4 to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe 22, the spiral guiding action of the spiral fin ring 27 on the inner wall of the water distribution pipe 22 forces the fluid to rotate, generating a centrifugal force to break the bubbles into smaller particle sizes. At the same time, the microbubble array of the dialysis holes 26 on the water distribution pipe 22 further cuts the bubbles to form a uniform microbubble group. The microbubble group contacts and breaks with the bump packages 212 arranged crosswise on the outer surface of the auxiliary net 211 on the surface of the ion exchange membrane 21 along with the water flow, generating local micro-jet impacts to peel off the calcium and magnesium ion scale initially deposited on the membrane surface; S3. The peeled calcium and magnesium ion scale particles settle to the water collection pipe 23 at the bottom of the membrane stack 2 along with the water flow, and are transported to the side branch drain pipe 5 through the drain pipe group 29 and the return pipeline 305. The low-salt wastewater and calcium and magnesium scale particles in the desalination chamber, and the high-salt wastewater and calcium and magnesium scale particles in the concentration chamber are discharged through the side branch drain pipe 5 and collected and processed externally.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An electric drive membrane desalination device, comprising a pipe rack (1), characterized in that, Further comprising: A membrane stack (2), installed on the right side of the pipe rack (1), with multiple ion exchange membranes (21) arranged in parallel stacked in the middle thereof, and a plurality of water distribution pipes (22) and water collection pipes (23) are arranged at equal intervals on the upper and lower parts of the ion exchange membrane (21); The ion exchange membrane (21) includes alternately arranged cation membranes and anion membranes, and alternately distributed desalination chambers and concentration chambers are formed between adjacent ion exchange membranes (21). The outermost sides on the left and right of the membrane stack (2) are the cathode chamber and the anode chamber respectively. Under the direct current electric field, ions migrate through the corresponding membranes to achieve directional separation of salts. Auxiliary meshes (211) are attached to both main surfaces on both sides of the ion exchange membrane (21), and bump packages (212) are arranged at equal intervals and crosswise on the outer surface of the auxiliary mesh (211); A pipe transportation assembly (3), installed in the middle of the pipe rack (1), for transporting the original liquid to the desalination chamber and the concentration chamber of the membrane stack (2) for circulation, and for transporting electrode water to the anode chamber and the cathode chamber; A bubble assembly (4), installed at the bottom of the membrane stack (2), for providing microbubbles in the original liquid transported in the lower water distribution pipe (22) of the membrane stack (2); An annular air pipe (24) is installed at the water inlet of the water distribution pipe (22). A plurality of exhaust ports (25) are equidistantly arranged on the inner wall of the annular air pipe (24). A one-way waterproof and breathable membrane is installed in each exhaust port (25). A plurality of dialysis holes (26) are equidistantly arranged on the water distribution pipe (22), and a plurality of spiral fin rings (27) are equidistantly installed on the inner wall of the water distribution pipe (22).

2. The electro-driven membrane desalination device according to claim 1, characterized in that, The outer surface of the bump package (212) is distributed with a rough burr surface (213), and a hydrophobic material (214) is applied on the bump package (212); The hydrophobic material (214) is polytetrafluoroethylene or a silane modified coating, and the coating thickness is 10 - 50 μm.

3. The electric drive membrane desalination device according to claim 1, characterized in that A partition mesh (215) is arranged between two adjacent ion exchange membranes (21), and a carbon electrode material (216) is embedded in the partition mesh (215).

4. The electric drive membrane desalination device according to claim 1, characterized in that, A liquid infusion pipe group (28) is arranged at the lower part of one side of the membrane stack (2). The liquid infusion pipe group (28) includes alternately arranged fresh water inlet pipes (281) and concentrated water inlet pipes (282), and both are connected to the water inlet of the corresponding water distribution pipe (22); A liquid discharge pipe group (29) is arranged at the upper part of the same side of the membrane stack (2). The liquid discharge pipe group (29) includes alternately arranged fresh water discharge pipes (291) and concentrated water discharge pipes (292), and both are connected to the water outlet of the corresponding water collection pipe (23); 5. The electric drive membrane desalination device according to claim 1, characterized in that, The pipe transportation assembly (3) includes: Tanks (300), three in number, all located at the rear of the pipe rack (1), which are the fresh water tank (301), the concentrated water tank (302) and the electrode water tank (303) in sequence from left to right; Delivery pumps (304), three in number, are equidistantly installed at the bottom of the pipe rack (1); The water outlets of the fresh water tank (301) and the concentrated water tank (302) are respectively connected to the inlets of the corresponding transfer pumps (304) through pipelines. The drain outlets of the transfer pumps (304) located at the left side and the middle of the bottom of the pipe rack (1) are connected to the liquid delivery pipe group (28) located at the lower part of the membrane stack (2) through pipelines. The liquid discharged from the liquid discharge pipe group (29) located at the upper part of the membrane stack (2) flows into the connected fresh water tank (301) and concentrated water tank (302) respectively through the return pipeline (305); The water outlet of the electrode water tank (303) is connected to the inlet of the corresponding transfer pump (304) through a pipeline. The outlet of the transfer pump (304) located at the right side of the bottom of the pipe rack (1) is connected to the liquid inlets of the cathode chamber and the anode chamber of the membrane stack (2) through a pipeline. The liquid outlets of the cathode chamber and the anode chamber flow into the connected electrode water tank (303) through the return pipeline (305).

6. The electric drive membrane desalination device according to claim 1, wherein The bubble assembly (4) includes: A locking frame (401), which is installed at the bottom of the membrane stack (2); A microbubble generator (402), which is installed at the bottom of the locking frame (401); An air outlet of the microbubble generator (402) is provided with a shunt cross pipe (403). One side of the shunt cross pipe (403) facing inwards is connected to one ends of a plurality of branch drain pipes (404) arranged at equal intervals. The other ends of the branch drain pipes (404) are connected to the air inlet of an annular air pipe (24) located at the water inlet of the water distribution pipe (22).

7. The electric drive membrane desalination device according to claim 4, characterized in that, Side branch drain pipes (5) are installed on the return pipelines (305) connected to the fresh water drain pipe (291) and the concentrated water drain pipe (292), and electromagnetic valves are installed on the side branch drain pipes (5).

8. The electric drive membrane desalination device according to claim 1, characterized in that, A control cabinet (6) is installed on the left side of the pipe rack (1). The control cabinet (6) is electrically connected to the three transfer pumps (304), the microbubble generator (402), and the electromagnetic valves on the side branch drain pipes (5).

9. A method for operating an electro-driven membrane desalination device, characterized in that, Using an electric-driven membrane desalination device according to any one of claims 1-8, the method includes the following steps: S1. Pump the raw water in the fresh water tank (301) into the desalination chamber of the membrane stack (2) through the transfer pump (304), pump the concentrated water circulating liquid in the concentrated water tank (302) into the concentration chamber, pump the electrode water in the electrode water tank (303) into the cathode chamber and the anode chamber at both ends of the membrane stack (2), apply a direct current electric field, cations migrate towards the cathode and pass through the cation exchange membrane into the concentration chamber, anions migrate towards the anode and pass through the anion exchange membrane into the concentration chamber, realizing the directional transfer of salt from the desalination chamber to the concentration chamber. The fresh water and the concentrated water after the first separation are respectively returned to the fresh water tank (301) and the concentrated water tank (302), and the cycle treatment is repeated until the fresh water produced in the desalination chamber meets the standard and is discharged and collected, and the concentrated water produced in the concentration chamber is enriched to the set concentration and then collected; S2. When membrane stack (2) cleaning is required, start the bubble component (4) to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe (22), the spiral guiding action of the spiral fin ring (27) on the inner wall of the water distribution pipe (22) forces the fluid to rotate, generating a centrifugal force to break the bubbles into smaller particle sizes. At the same time, the microbubble array of dialysis holes (26) on the water distribution pipe (22) further cuts the bubbles to form a uniform microbubble group. The microbubble group contacts and breaks with the convex point packages (212) arranged crosswise on the outer surface of the auxiliary net (211) on the surface of the ion exchange membrane (21) along with the water flow, generating local micro-jet impacts to peel off the calcium and magnesium ion scale initially deposited on the membrane surface; S3. The peeled calcium and magnesium ion scale particles settle to the water collecting pipe (23) at the bottom of the membrane stack (2) along with the water flow, and are transported to the side branch drain pipe (5) through the drain pipe group (29) and the return pipeline (305). The low-salt wastewater and calcium and magnesium scale particles in the desalination chamber, as well as the high-salt wastewater and calcium and magnesium scale particles in the concentration chamber, are discharged through the side branch drain pipe (5) and externally collected and treated.

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