An electrically driven membrane desalination device and an operating method thereof

Abstract

The present invention relates to the technical field of electric-driven membrane desalination devices, and provides an electric-driven membrane desalination device and an operating method thereof, comprising a pipe rack, and further comprising: a membrane stack, mounted on the right side of the pipe rack, wherein a plurality of parallel ion exchange membranes are stacked in the middle, a plurality of water distribution pipes and water collection pipes are equidistantly arranged on the upper and lower parts of the ion exchange membranes; the ion exchange membranes comprise alternating cation membranes and anion membranes, desalination chambers and concentration chambers are formed between adjacent ion exchange membranes, the left and right outermost sides of the membrane stack are cathode chambers and anode chambers, auxiliary nets are attached to the main surfaces of both sides of the ion exchange membranes, and convex dot packages are equidistantly and cross-arranged on the outer surfaces of the auxiliary nets; a piping assembly is mounted in the middle of the pipe rack. When in use, the present invention utilizes a bubble cleaning mechanism to reduce the amount of calcium and magnesium ion scaling on the membrane surface, avoid clogging of the membrane pores, maintain the permeability of the ion exchange membrane, and ensure the desalination efficiency of the electric-driven membrane desalination device.

Description

Technical Field

[0001] The present invention relates to the technical field of electrically driven membrane desalination devices, and more particularly to an electrically driven membrane desalination device and an operating method thereof. Background Art

[0002] Electric-driven membrane desalination technology is a water treatment technology that achieves selective ion separation based on the action of an electric field. Its core is to use the selective permeability characteristics of ion exchange membranes combined with a DC electric field to drive ion migration, thereby achieving the removal or concentration of salt in the solution.

[0003] Prior art (publication number: CN101690869A, classification number: B01D61 / 58) discloses that the salt water discharged from the electrodialysis concentration chamber is subjected to reverse osmosis to produce reverse osmosis fresh water. Electrodialysis concentration is an electrically driven membrane desalination technology.

[0004] Driven by a DC electric field, multivalent calcium and magnesium ions tend to accumulate on the surface of the ion exchange membrane due to their high charge density and slow migration rate. At the same time, the water electrolysis induced by the electric field will lead to a 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 and hydroxide in water to form insoluble salts such as CaCO3 and Mg(OH)2.

[0005] In the above process, high concentrations of calcium and magnesium ions will cause the membrane pores to be blocked and the active sites to be covered, thereby 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, aggravates the local concentration polarization and the vicious cycle of membrane pollution, and multivalent ions compete with monovalent target ions for migration, ultimately reducing the membrane separation efficiency and leading to a decrease in the desalination rate.

[0006] To this end, the present application proposes an electrically driven membrane desalination device and an operating method thereof to solve the above problems. Summary of the Invention

[0007] Technical problem to be solved: In response to the problems existing in the prior art, the purpose of the present invention is to provide an electrically driven membrane desalination device and an operating method thereof, which solves the problem of membrane pore blockage and active site coverage of the existing ion exchange membrane caused by high-concentration calcium and magnesium ion scaling, resulting in the inability to maintain the ion exchange permeability of the ion exchange membrane, and reducing the desalination efficiency of the electrically driven membrane desalination device.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: an electrically driven membrane desalination device, comprising a pipe rack, and also comprising: a membrane stack, installed on the right side of the pipe rack, wherein a plurality of parallel ion exchange membranes are stacked in the middle, and a plurality of water distribution pipes and water collection pipes are equidistantly arranged at the upper and lower parts of the ion exchange membranes; the ion exchange membranes comprise alternating cation membranes and anion membranes, and alternating desalination chambers and concentration chambers are formed between adjacent ion exchange membranes, and the outermost sides of the membrane stack are cathode chambers and anode chambers respectively. Under a DC electric field, ions migrate through the corresponding membranes to achieve directional separation of salt, and the main surfaces on both sides of the ion exchange membranes are connected. An auxiliary net is attached to the surface, and convex bags are arranged at equal intervals and cross-wise on the outer surface of the auxiliary net; a pipe transport component is installed in the middle of the pipe rack, which is used to transport and circulate the raw liquid to the desalination chamber and concentration chamber of the membrane stack, and to transport polar water to the anode chamber and cathode chamber; a bubble component is installed at the bottom of the membrane stack, which is used to provide microbubbles in the raw liquid transported in the water distribution pipe 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, and a one-way waterproof and breathable membrane is installed in the exhaust port, 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 the bump package is coated with a hydrophobic material; the hydrophobic material is polytetrafluoroethylene or a silane modified coating, and the coating thickness is 10 to 50 μm.

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

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

[0012] In a new embodiment, the piping assembly includes: three tank bodies, all of which are located at the rear of the pipe rack, namely, a fresh water tank, a concentrated water tank and a polar water tank from left to right; three delivery pumps are provided, which are installed equidistantly at the bottom of the pipe rack; the water outlets of the fresh water tank and the concentrated water tank are connected to the corresponding water inlets of the delivery pumps through pipes, the discharge ends of the delivery pumps located on the left and middle of the bottom of the pipe rack are connected to the infusion pipe group located at the bottom of the membrane stack through pipes, and the liquid discharged from the discharge pipe group located at the top of the membrane stack flows into the connected fresh water tank and concentrated water tank respectively through reflux pipes; the water outlet of the polar water tank is connected to the corresponding water inlet of the delivery pump through a pipe, the water outlet end of the delivery pump located on the right side of the bottom of the pipe rack is connected to the liquid inlets of the cathode chamber and the anode chamber of the membrane stack through a pipe, and the liquid outlets of the cathode chamber and the anode chamber flow into the connected polar water tank through reflux pipes.

[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; the air outlet of the microbubble generator is installed with a diversion cross pipe, and the inward side of the diversion cross pipe is connected to one end of a plurality of branch pipes arranged at equal intervals, and the other end of the branch pipe is connected to the air inlet of the ring pipe located in the water inlet of the water distribution pipe.

[0014] In a new embodiment, the return pipes connecting the fresh water pipe and the concentrated water pipe are both installed with branch pipes, and the branch pipes are both installed with solenoid valves.

[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 delivery pumps, the microbubble generator and the solenoid valves on the side branch pipes.

[0016] A method for operating an electrically driven membrane desalination device comprises the following steps:

[0017] S1. The raw water in the fresh water tank is pumped into the desalination chamber of the membrane stack by a transfer pump, the concentrated water circulating liquid in the concentrated water tank is pumped into the concentrating chamber, and the polar water in the polar water tank is pumped into the cathode chamber and anode chamber at both ends of the membrane stack. A DC electric field is applied, causing cations to migrate toward the cathode and pass through the cation membrane into the concentrating chamber, while anions to migrate toward the anode and pass through the anion membrane into the concentrating chamber, thereby achieving a directional transfer of salt from the desalination chamber to the concentrating chamber. The fresh water and concentrated water that have been separated once are returned to the fresh water tank and concentrated water tank, respectively. The cycle is repeated until the fresh water produced by the desalination chamber meets the standards and is then discharged and collected, and the concentrated water produced by the concentrating chamber is enriched to the set concentration and then collected;

[0018] S2. When the membrane stack needs to be cleaned, the bubble assembly is started to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe, the spiral diversion effect of the spiral fin ring on the inner wall of the water distribution pipe forces the fluid to rotate, generating centrifugal force to break the bubbles into smaller particles. At the same time, the dialysis hole microporous array on the water distribution pipe further cuts the bubbles to form a uniform microbubble group. The microbubble group ruptures with the contact of the cross-arranged convex point packages on the outer surface of the auxiliary net on the surface of the ion exchange membrane along with the water flow, generating local microjet impact, and stripping the calcium and magnesium ion scaling initially deposited on the membrane surface;

[0019] S3. The stripped calcium and magnesium ion scaling 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 drainage pipe group and the return pipe. The low-salt wastewater and calcium and magnesium scaling particles in the desalination chamber, and the high-salt wastewater and calcium and magnesium scaling particles in the concentration chamber are discharged through the side branch drain pipe and collected and treated externally.

[0020] Beneficial effects: Compared with the prior art, the advantages of the present invention are: 1. In the process of cleaning the ion exchange membrane, the bubbles generated by the bubble assembly are broken into smaller particles and form a rotating gas-liquid mixed flow through the synergistic effect of the annular air pipe, spiral fin ring and dialysis pores. The microbubbles are impacted by the water flow to the convex points on the surface of the auxiliary network and burst, generating local microjets to accurately peel off the calcium and magnesium ion scaling initially formed on the surface of the ion exchange membrane, avoiding clogging of the membrane pores and maintaining the permeability and desalination efficiency of the ion exchange membrane. This process utilizes hydrogen or air microbubbles generated by electrolysis, and there is no secondary pollution after bursting. The cleaning effect is significant and environmentally friendly.

[0021] 2. The spiral fin ring on the inner wall of the water distribution pipe forces the gas-liquid flow to rotate, using centrifugal force to break bubbles into smaller particles. The microporous array of the bottom dialysis well further cuts the bubbles, forming a uniform microbubble group. The rotating flow drives the microbubbles in the direction of the dialysis well to impact the membrane surface, enhancing the uniformity of bubble rupture and the efficiency of scale removal.

[0022] 3. A one-way waterproof and breathable membrane is installed in the exhaust port of the ring air pipe at the water inlet of the water distribution pipe. Its selective permeability only allows micro bubbles to be released into the water distribution pipe, preventing the reverse infiltration of fresh water, concentrated water or extreme water, and avoiding bubble component failure or pipeline corrosion caused by liquid backflow.

[0023] 4. On the auxiliary net attached to both sides of the ion exchange membrane, convex packages are arranged at equal intervals and crosswise. The rough burr surface can reduce the energy required for bubble bursting, making microbubbles easier to break at the convex packages, generating dense microjets. At the same time, the polytetrafluoroethylene or silane-modified hydrophobic coating coated on the convex packages can block the ion-enriched environment required for scale nucleation and reduce scale adhesion. In addition, the convex packages are small in size and dispersed in distribution, which does not affect the core function of the ion exchange membrane, but can accurately strike the scaling area through the needle tip effect, achieving low energy consumption and high efficiency scale prevention.

[0024] 5. The pipeline component realizes the directional transportation and recycling of raw liquid, concentrated water and polar water through the circulation pipeline of fresh water tank, concentrated water tank, polar water tank and delivery pump. The side branch discharge pipe collects low-salt wastewater in the desalination chamber, high-salt wastewater in the concentration chamber and stripped calcium and magnesium ion scaling particles through external discharge, avoiding membrane pore blockage and flow channel pollution caused by scaling accumulation, realizing wastewater classification treatment and improving the anti-pollution ability of membrane stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure from another perspective of the present invention.

[0027] Figure 3 It is a schematic diagram of the tank position structure of the present invention.

[0028] Figure 4 It is a schematic diagram of the structure of the pipeline assembly of the present invention.

[0029] Figure 5 It is a schematic diagram of the membrane stack structure of the present invention.

[0030] Figure 6 It is a schematic structural diagram of the interception component of the present invention.

[0031] Figure 7 It is a schematic structural diagram of the bubble assembly of the present invention.

[0032] Figure 8 This is a schematic diagram of the water distribution pipe installation position structure of the present invention.

[0033] Figure 9 It is a schematic diagram of the internal structure of the water distribution pipe of the present invention.

[0034] Figure 10 Schematic diagram of the ring air pipe structure of the present invention.

[0035] Figure 11 This is a schematic diagram of the spiral fin ring position structure of the present invention.

[0036] Figure 12 Schematic diagram of the ion exchange membrane structure of the present invention.

[0037] Figure 13 It is a schematic diagram of the ion exchange membrane splitting structure of the present invention.

[0038] Figure 14 It is a schematic diagram of the partition net structure of the present invention.

[0039] Figure 15 For the present invention Figure 12 A magnified view of the structure at point A.

[0040] Figure 16 Schematic diagram of the impact area of ​​the convex package broken bubbles of the present invention.

[0041] The accompanying drawings are marked as follows: 1, pipe rack; 2, membrane stack; 21, ion exchange membrane; 211, auxiliary mesh; 212, bump package; 213, rough burr surface; 214, hydrophobic material; 215, separator mesh; 216, carbon electrode material; 22, water distribution pipe; 23, water collection pipe; 24, ring air pipe; 25, exhaust port; 26, dialysis hole; 27, spiral fin ring; 28, infusion pipe group; 281, fresh water inlet pipe; 282, concentrate water inlet pipe; 29, drainage pipe group; 291, fresh water discharge pipe; 292, concentrate discharge pipe;

[0042] 3. Pipeline assembly; 300. Tank body; 301. Fresh water tank; 302. Concentrated water tank; 303. Extreme water tank; 304. Delivery pump; 305. Return line;

[0043] 4. Bubble assembly; 401. Locking frame; 402. Microbubble generator; 403. Diversion cross pipe; 404. Branch pipe;

[0044] 5. Side branch pipes; 6. Control cabinet. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only 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 ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] The embodiments of the present application provide an electrically driven membrane desalination device and an operating method thereof, thereby solving the problem of pore blockage and active site coverage of the ion exchange membrane caused by scaling of high-concentration calcium and magnesium ions, which results in the inability to maintain the ion exchange permeability of the ion exchange membrane and reduces the desalination efficiency of the electrically driven membrane desalination device. During use, a bubble cleaning mechanism is utilized to reduce the amount of calcium and magnesium ion scaling on the membrane surface, avoid pore blockage, maintain the permeability of the ion exchange membrane, and ensure the desalination efficiency of the electrically driven membrane desalination device.

[0047] The technical solution in the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows.

[0048] Example 1, please refer to Figures 1-16, the embodiment of the present application provides an electric-driven membrane desalination device, including a pipe rack 1, and also including: a membrane stack 2, which is installed on the right side of the pipe rack 1, and a plurality of parallel ion exchange membranes 21 are stacked in the middle, and a plurality of water distribution pipes 22 and water collection pipes 23 are equidistantly arranged at the upper and lower parts of the ion exchange membrane 21; the ion exchange membrane 21 includes alternating cation membranes and anion membranes, and adjacent ion exchange membranes 21 form alternating desalination chambers and concentration chambers, and the outermost sides of the membrane stack 2 are respectively the cathode chamber and the anode chamber. Under the DC electric field, ions migrate through the corresponding membrane to achieve directional separation of salt. Auxiliary nets 211 are attached to the main surfaces of both sides of the ion exchange membrane 21. The outer surface of the net 211 is cross-arranged with convex dot packages 212 at equal intervals; the pipe transport component 3 is installed in the middle of the pipe rack 1, and is used to transport and circulate the raw liquid to the desalination chamber and concentration chamber of the membrane stack 2, and to transport polar water to the anode chamber and cathode chamber; the bubble component 4 is installed at the bottom of the membrane stack 2, and is used to provide microbubbles in the raw liquid transported in the water distribution pipe 22 at the lower part 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 opened on the inner ring wall of the annular air pipe 24, and a one-way waterproof and breathable membrane is installed in the exhaust ports 25, a plurality of dialysis holes 26 are equidistantly opened 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.

[0049] In this example, see Figures 1-16 As shown, the ion exchange membrane 21 is arranged alternately with cationic membranes and anionic membranes to form a periodic arrangement of desalination chambers and concentration chambers. Under the action of the electric field, the cations in the water can be driven to migrate to the cathode through the cationic membrane and the anions can be driven to migrate to the anode through the anionic membrane, so that the ion concentration in the desalination chamber is rapidly reduced and the ions in the concentration chamber are efficiently enriched, which significantly improves the salt separation efficiency and meets the needs of high-purity fresh water preparation.

[0050] During the electrically driven membrane water treatment process, the two main surfaces of the cation membrane and the anion membrane of the ion exchange membrane 21 are easily attached with calcium and magnesium ions and form scale due to the action of the electric field. Traditional methods are difficult to achieve effective cleaning. Therefore, this technology uses a dual mechanism of regular integrated microbubble generation and surface structure optimization of the ion exchange membrane 21 to perform microbubble cleaning on the scaling state of calcium and magnesium ions on the two main surfaces of the ion exchange membrane 21, keeping the membrane surface of the ion exchange membrane 21 from being blocked, ensuring the normal ion exchange operation of the ion exchange membrane 21, and maintaining the desalination efficiency.

[0051] By setting the water distribution pipe 22, the ring air pipe 24, the exhaust port 25, the one-way waterproof breathable membrane, the dialysis hole 26 and the spiral fin ring 27, the bubble component 4 first generates micron-level bubbles through the electrolysis water technology and transports them to the connected ring air pipe 24. The ring air pipe 24 discharges the bubbles to the water inlet of the water distribution pipe 22 through the annular exhaust port 25 on the inner ring wall, and as the liquid entering the water distribution pipe 22 flows, it enters the pipe part of the water distribution pipe 22 buried in the membrane stack 2, and as the liquid and bubbles flow in, they will also be connected to the water distribution pipe 22. The spiral fin ring 27 inside contacts to form a gas-liquid mixed flow, and the water distribution pipe 22 forces the gas-liquid flow to rotate, generating flow centrifugal force to break the bubbles into smaller particle sizes, and the bubbles are discharged from the dialysis holes 26 of the microporous array at the bottom of the water distribution pipe 22. The rotating flow drives the microbubbles along the osmotic falling direction of the dialysis holes 26 to impact the two main surfaces of the ion exchange membrane 21, and the convex packages 212 on the auxiliary net 211 that are attached to the two surfaces of the ion exchange membrane 21 come into contact and break, generating microjets to peel off the calcium and magnesium ion scaling on the ion exchange membrane 21 and the auxiliary net 211.

[0052] It should be noted that the one-way waterproof and breathable membrane in the exhaust port 25 has selective permeability, allowing microbubbles to be released from the liquid flowing from the exhaust port 25 to the water inlet of the water distribution pipe 22, preventing fresh water and concentrated water from reversely permeating into the annular air pipe 24, avoiding failure of the bubble component 4 or pipeline corrosion caused by liquid backflow, and the porosity and surface tension of the membrane material of the one-way breathable waterproof net can withstand greater water side pressure, ensuring the sealing of the bubble path during the operation of the device and maintaining stable bubble generation efficiency.

[0053] In terms of surface structure optimization of the ion exchange membrane 21, an auxiliary net 211 is attached to the two main surfaces of the ion exchange membrane 21. The auxiliary net 211 has equidistant and cross-arranged convex bags 212. The microbubbles released through the dialysis holes 26 of the water distribution pipe 22 come into contact with the convex bags 212 on the auxiliary net 211 on the two main surfaces of the ion exchange membrane 21 as the liquid flows. The convex bags 212 are like needle tips. When the microbubbles come into contact with the convex bags 212, they will "bang" and burst, generating a very small water flow microjet reference. Figure 16 The shaded area represents the impact range of the microjet. Although the impact force is small, it is enough to peel off the newly formed calcium and magnesium ion scale particles from the ion exchange membrane 21 and the auxiliary network 211. At the same time, the position of the convex package 212 represents the position where the bubble ruptures, which can accurately strike the calcium and magnesium ion scale initially formed in the convex package 212 area. Since the microbubbles are hydrogen or air generated by electrolysis of water, there is no secondary pollution after rupture, which can significantly reduce calcium and magnesium ion scaling, maintain the clean and unobstructed surface of the ion exchange membrane 21, and ensure the continuous and efficient operation of the electrically driven membrane separator.

[0054] Further, see Figure 13 and Figure 14A separator net 215 is provided between two adjacent ion exchange membranes 21 , and a carbon electrode material 216 is embedded in the separator net 215 .

[0055] A separator mesh 215 is located between adjacent ion exchange membranes 21. This serves as a spacer and support for the membranes 21, maintaining equidistant and parallel alignment of adjacent membranes, preventing blockage caused by membrane adhesion and ensuring stability in the desalination and concentration compartments. Carbon electrode material 216, such as activated carbon or carbon fiber, embedded in the separator mesh 215 acts as a local conductive medium, forming independent conductive units between adjacent ion exchange membranes 21. This unit, in conjunction with the cathode / anode electrodes at both ends of the membrane stack 2, creates a multi-level electric field network. This localized electric field shifts the ion migration distance from the desalination compartment to the concentration compartment from being dependent on the overall electric field of the membrane stack 2 to being dependent on the micro-electric fields of adjacent electrodes, reducing migration resistance and improving separation efficiency. It should be noted that the separator mesh 215 is categorized as anode, freshwater, and concentrate. The order of arrangement of the ion exchange membranes 21 and separator mesh 215 is as follows: anode plate → anode separator → cation membrane → freshwater separator → anion membrane → concentrate separator → ... → cathode plate.

[0056] Further, see Figure 13 and Figure 15 The outer surface of the bump package 212 is distributed with a rough burr surface 213, and the bump package 212 is coated with a hydrophobic material 214; the hydrophobic material 214 is a polytetrafluoroethylene or silane modified coating, and the coating thickness is 10 to 50 μm.

[0057] By providing the rough burr surface 213 and the hydrophobic material 214, the rough burr surface 213 on the surface of the convex package 212 increases the microscopic roughness of the membrane surface, thereby forming dense bubble rupture sites. When the microbubbles flow along with the water flow and contact the convex package 212, the burrs on the rough surface can significantly reduce the energy required for the bubble rupture, making the microbubbles easier to break at the convex package 212. The microjets generated by the breakage can accurately act on the calcium and magnesium ion scaling such as CaCO3 and MgOH2 microcrystals initially formed on the surface of the ion exchange membrane 21, and peel them off from the membrane surface through the impact force, thereby preventing the scaling layer from further growing and thickening. At the same time, the convex package 21 2 is coated with a hydrophobic material 214 having low surface energy characteristics, similar to the coating of a non-stick pan, which makes it difficult for scale to stick to the bumps 212, blocking the ion enrichment environment required for scale nucleation, and keeping the bumps 212 clean. The bumps 212 are located on the auxiliary network 211, and their small size and cross-dispersion will neither affect the main function of ion exchange of the ion exchange membrane 21 nor require complex improvements to the ion exchange membrane 21. It is only necessary to add auxiliary networks 211 on its two main surfaces. It should be noted that the auxiliary network 211 does not affect the ion exchange operation of the ion exchange membrane 21.

[0058] Further, see Figure 7-Figure 9 A liquid infusion pipe group 28 is provided at the lower part of one side of the membrane stack 2, and the liquid infusion pipe group 28 includes a fresh water inlet pipe 281 and a concentrated water inlet pipe 282 arranged alternately, and both are connected to the water inlet of the corresponding water distribution pipe 22; a liquid discharge pipe group 29 is provided at the upper part of the same side of the membrane stack 2, and the liquid discharge pipe group 29 includes a fresh water discharge pipe 291 and a concentrated water discharge pipe 292 arranged alternately, and both are connected to the water outlet of the corresponding water collecting pipe 23.

[0059] The liquid infusion pipe group 28 includes a fresh water inlet pipe 281 and a concentrated water inlet pipe 282, both of 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, both of which provide fresh water and concentrated water discharge interfaces for the water collecting pipe 23 on the membrane stack 2.

[0060] Further, see Figure 5-Figure 9 The bubble assembly 4 includes: a locking frame 401, installed at the bottom of the membrane stack 2; a microbubble generator 402, installed at the bottom of the locking frame 401; a diversion cross pipe 403 is installed at the air outlet of the microbubble generator 402, and the inward side of the diversion cross pipe 403 is connected to one end of a plurality of branch pipes 404 arranged at equal distances, and the other end of the branch pipe 404 is connected to the air inlet of the ring air pipe 24 located in the water inlet of the water distribution pipe 22.

[0061] The locking frame 401 is fixed to the bottom of the membrane stack 2 through the locking frame 401, the microbubble generator 402, the diversion cross pipe 403 and the branch row pipe 404, providing a stable installation foundation for the microbubble generator 402. The microbubbles generated by the microbubble generator 402 during operation enter the diversion cross pipe 403 through the air outlet, and the bubbles are evenly distributed to the equally spaced branch row pipes 404 through its internal flow channel. The end of each branch row pipe 404 is connected to the air inlet of the ring 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 ring air pipe 24, and finally enter the flow channel 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.

[0062] Further, see Figure 1-Figure 4The pipe transport assembly 3 includes: three tanks 300, all located at the rear of the pipe rack 1, namely, the fresh water tank 301, the concentrated water tank 302 and the polar water tank 303 from left to right; three delivery pumps 304, 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 connected to the corresponding water inlet of the delivery pump 304 through pipes, and the discharge end of the delivery pump 304 located on the left and middle of the bottom of the pipe rack 1 is connected to the infusion port located at the bottom of the membrane stack 2 through pipes. The pipe group 28 is connected, and the liquid discharged from the discharge pipe group 29 located on 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 pipe 305; the water outlet of the polar water tank 303 is connected with the water inlet end of the corresponding delivery pump 304 through a pipeline, and the water outlet end of the delivery pump 304 located on the right side of the bottom of the pipe rack 1 is connected with the liquid inlet of the cathode chamber and the anode chamber of the membrane stack 2 through a pipeline, and the liquid outlet of the cathode chamber and the anode chamber flows into the connected polar water tank 303 through the return pipe 305.

[0063] The fresh water tank 301, concentrated water tank 302 and extreme water tank 303 store the brine to be treated, the circulating concentrated water and the extreme water respectively. Three delivery pumps 304 are connected to the corresponding tanks 300 to provide power for the delivery of liquids.

[0064] The delivery pump 304 connects the raw liquid in the concentrated water tank 302 and the fresh water tank 301 to the infusion tube group 28 through a pipeline, and then pumps it into the concentration chamber and desalination chamber of the membrane stack 2. The liquid discharged from the concentration chamber and the desalination chamber then flows back to the concentrated water tank 302 and the fresh water tank 301 through the return pipe 305. This cycle reduces the salt content in the water. Finally, the treated liquid discharged from the concentration chamber and the desalination chamber is collected through the discharge pipe (not shown in the figure). Among them, the polar water tank 303 also delivers polar water to the cathode chamber and the anode chamber of the membrane stack 2 through the delivery pump 304 to replenish the polar water inside the two. It can also be recycled or recovered with the return pipe 305.

[0065] Further, see Figure 6 The return line 305 connecting the fresh water drain pipe 291 and the concentrated water drain pipe 292 is installed with a side branch drain pipe 5, and the side branch drain pipe 5 is installed with a solenoid valve.

[0066] By setting up a side branch drain pipe 5, the scouring effect of microbubbles is utilized to strip off the calcium and magnesium ion scaling particles attached to the surface of the ion exchange membrane 21 into a suspended state and discharged with the water flow to the water collecting pipe 23. The scaling particles are discharged into the side branch drain pipe 5 with the electromagnetic valve opened through the drainage pipe group 29 connected to the water collecting pipe 23 and the reflux pipe 305 connected to the drainage pipe group 29, and are collected and discharged outside through the side branch drain pipe 5, thereby separately collecting the wastewater discharged from the desalination chamber and the concentration chamber and the stripped calcium and magnesium ion scaling particles. This process avoids the clogging of the membrane pores and the decrease in separation efficiency caused by long-term adhesion of scaling through the synergistic effect of microbubble scouring and the side branch drain pipe 5, realizes the directional interception and discharge of scaling particles, the graded treatment of wastewater and the anti-clogging of the flow channel of the membrane stack 2, and improves the anti-pollution ability and separation efficiency of the membrane component.

[0067] Further, see Figure 1-Figure 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 pipe 5. The control cabinet 6 is used to monitor the working status of the three delivery pumps 304, the microbubble generator 402 and the solenoid valve on the side branch pipe 5 in real time, and can be controlled to be opened separately. For example, when it is necessary to strip calcium and magnesium ion scaling from the membrane stack 2, the microbubble generator 402 and the solenoid valve on the side branch pipe 5 are opened to clean the bubble mechanism while collecting the discharged wastewater and impurities.

[0068] Example 2, please refer to Figures 1-16 , the embodiment of the present application also provides an operating method of an electrically driven membrane desalination device, comprising the following steps:

[0069] S1. The raw water in the fresh water tank 301 is pumped into the desalination chamber of the membrane stack 2 by the delivery pump 304. The concentrated water circulating liquid in the concentrated water tank 302 is pumped into the concentrating chamber. The polar water in the polar water tank 303 is pumped into the cathode chamber and the anode chamber at both ends of the membrane stack 2. A DC electric field is applied. The cations migrate toward the cathode and pass through the cation membrane into the concentrating chamber, while the anions migrate toward the anode and pass through the anion membrane into the concentrating chamber, thereby achieving a directional transfer of salt from the desalination chamber to the concentrating chamber. The fresh water and concentrated water separated once are returned to the fresh water tank 301 and the concentrated water tank 302, respectively. The cycle is repeated until the fresh water produced by the desalination chamber meets the standards and is discharged and collected, and the concentrated water produced by the concentrating chamber is enriched to a set concentration and collected;

[0070] S2. When the membrane stack 2 needs to be cleaned, the bubble assembly 4 is started to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe 22, the spiral guide effect of the spiral fin ring 27 on the inner wall of the water distribution pipe 22 forces the fluid to rotate, generating centrifugal force to break the bubbles into smaller particle sizes. At the same time, the bubbles are further cut by the microporous array of the dialysis holes 26 on the water distribution pipe 22 to form a uniform microbubble group. The microbubble group contacts and ruptures with the cross-arranged convex point packages 212 on the outer surface of the auxiliary mesh 211 on the surface of the ion exchange membrane 21 along with the water flow, generating local microjet impact, and stripping the calcium and magnesium ion scaling initially deposited on the membrane surface;

[0071] S3. The stripped calcium and magnesium ion scaling particles settle to the water collecting pipe 23 at the bottom of the membrane stack 2 with the water flow, and are transported to the side branch drain pipe 5 through the drainage pipe group 29 and the return pipe 305. The low-salt wastewater and calcium and magnesium scaling particles in the desalination chamber and the high-salt wastewater and calcium and magnesium scaling particles in the concentration chamber are discharged through the side branch drain pipe 5 and collected and treated externally.

[0072] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An electrically driven membrane desalination device, comprising a pipe rack (1), characterized in that: Also includes: A membrane stack (2) is installed on the right side of the pipe rack (1), wherein a plurality of ion exchange membranes (21) are stacked in parallel in the middle thereof, and a plurality of water distribution pipes (22) and water collection pipes (23) are arranged equidistantly above and below the ion exchange membranes (21); The ion exchange membrane (21) includes alternating cation membranes and anion membranes, and adjacent ion exchange membranes (21) form alternating desalination chambers and concentration chambers. The left and right outermost portions of the membrane stack (2) are cathode chambers and anode chambers, respectively. Under a direct current electric field, ions migrate through the corresponding membranes to achieve directional separation of salt. Auxiliary nets (211) are attached to the main surfaces of both sides of the ion exchange membrane (21), and convex dot packages (212) are arranged equidistantly and crosswise on the outer surface of the auxiliary net (211); The pipe transport assembly (3) is installed in the middle of the pipe rack (1) and is used to transport and circulate the raw liquid to the desalination chamber and the concentration chamber of the membrane stack (2), and to transport the polar water to the anode chamber and the cathode chamber; A bubble assembly (4) is installed at the bottom of the membrane stack (2) and is used to provide microbubbles in the raw liquid transported in the water distribution pipe (22) at the bottom of the membrane stack (2); A ring air pipe (24) is installed at the water inlet of the water distribution pipe (22), a plurality of exhaust ports (25) are evenly spaced on the inner wall of the ring air pipe (24), and a one-way waterproof breathable membrane is installed in each exhaust port (25). A plurality of dialysis holes (26) are evenly spaced on the water distribution pipe (22), and a plurality of spiral fin rings (27) are evenly spaced on the inner wall of the water distribution pipe (22); The pipeline assembly (3) comprises: There are three tank bodies (300), all located at the rear of the pipe rack (1), which are, from left to right, a fresh water tank (301), a concentrated water tank (302), and an extreme water tank (303); Three delivery pumps (304) are provided and are installed at equal intervals 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 of the corresponding delivery pump (304) through pipelines, the discharge end of the delivery pump (304) located at the left and middle part of the bottom of the pipe rack (1) is connected to the delivery pipe group (28) located at the bottom of the membrane stack (2) through pipelines, and the liquid discharged from the discharge pipe group (29) located at the top 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 of the corresponding delivery pump (304) through a pipeline, and the water outlet of the delivery pump (304) located on 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, and the liquid outlets of the cathode chamber and the anode chamber flow into the connected polar water tank (303) through the return pipeline (305); A drainage pipe group (29) is provided on the upper portion of the same side of the membrane stack (2); The drainage pipe group (29) includes fresh water drainage pipes (291) and concentrated water drainage pipes (292) arranged in an alternating manner, and both are connected to the outlet of the corresponding water collecting pipe (23). The return line (305) connecting the fresh water drainage pipes (291) and concentrated water drainage pipes (292) is installed with a side branch drainage pipe (5).

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

3. The electrically driven membrane desalination device according to claim 1, characterized in that: A separator net (215) is provided between two adjacent ion exchange membranes (21), and a carbon electrode material (216) is embedded in the separator net (215).

4. The electrically driven membrane desalination device according to claim 1, characterized in that: A liquid delivery pipe group (28) is provided at the lower portion of one side of the membrane stack (2). The liquid delivery pipe group (28) includes a fresh water inlet pipe (281) and a concentrated water inlet pipe (282) arranged alternately, and both are connected to the water inlet of the corresponding water distribution pipe (22).

5. The electrically driven membrane desalination device according to claim 1, characterized in that: The bubble assembly (4) comprises: A locking frame (401) is mounted on the bottom of the membrane stack (2); A microbubble generator (402) is mounted on the bottom of the locking frame (401); The air outlet of the microbubble generator (402) is equipped with a diversion transverse pipe (403), and the inward side of the diversion transverse pipe (403) is connected to one end of a plurality of branch pipes (404) arranged at equal intervals, and the other end of the branch pipes (404) is connected to the air inlet of the ring air pipe (24) located in the water inlet of the water distribution pipe (22).

6. The electrically driven membrane desalination device according to claim 4, characterized in that: Solenoid valves are installed on the side branch pipes (5).

7. The electrically driven 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), and 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 pipe (5).

8. A method for operating an electrically driven membrane desalination device, characterized in that: An electrically driven membrane desalination device according to any one of claims 1 to 7 comprises the following steps: S1. The raw water in the fresh water tank (301) is pumped into the desalination chamber of the membrane stack (2) by the delivery pump (304), the concentrated water circulating liquid in the concentrated water tank (302) is pumped into the concentration chamber, and the polar water in the polar water tank (303) is pumped into the cathode chamber and the anode chamber at both ends of the membrane stack (2). A DC electric field is applied, and the cations migrate toward the cathode and pass through the cation membrane into the concentration chamber, and the anions migrate toward the anode and pass through the anion membrane into the concentration chamber, thereby realizing the directional transfer of salt from the desalination chamber to the concentration chamber. The fresh water and concentrated water separated once are returned to the fresh water tank (301) and the concentrated water tank (302) respectively. The cycle is repeated until the fresh water produced by the desalination chamber meets the standard and is discharged and collected, and the concentrated water produced by the concentration chamber is enriched to a set concentration and collected; S2. When the membrane stack (2) needs to be cleaned, the bubble assembly (4) is started to continuously generate microbubbles. When the gas-liquid mixed flow flows along the water distribution pipe (22), the spiral guide effect of the spiral fin ring (27) on the inner wall of the water distribution pipe (22) forces the fluid to rotate, generating centrifugal force to break the bubbles into smaller particle sizes. At the same time, the micropore array of the dialysis hole (26) on the water distribution pipe (22) further cuts the bubbles to form a uniform microbubble group. The microbubble group contacts and ruptures with the cross-arranged convex point package (212) on the outer surface of the auxiliary network (211) on the surface of the ion exchange membrane (21) along with the water flow, generating a local microjet impact, and stripping the calcium and magnesium ion scaling initially deposited on the membrane surface; S3. The stripped calcium and magnesium ion scaling particles settle with the water flow to the water collecting pipe (23) at the bottom of the membrane stack (2), and are transported to the side branch drain pipe (5) through the drainage pipe group (29) and the return pipe (305). The low-salt wastewater and calcium and magnesium scaling particles in the desalination chamber and the high-salt wastewater and calcium and magnesium scaling particles in the concentration chamber are discharged through the side branch drain pipe (5) and collected and treated externally.

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