Anion-cathode double-membrane type electrodeionization device

Abstract

The utility model discloses an anion and cation double-membrane type electrodeionization device. The device internally comprises a cathode chamber, a resin chamber and an anode chamber; the cathode chamber and the resin chamber are isolated by a cation exchange membrane, the anode chamber and the resin chamber are isolated by an anion exchange membrane, and the distance between the two membranes is 10-100cm. According to the utility model, the electric regeneration efficiency of the invalid resin and the quality of subsequent produced water can be obviously improved, electrolyte solution is not consumed, the environmental protection problem is avoided, an electrode water circulating pump can be omitted, and the system and operation management are simplified.

Description

Technical Field

[0001] This utility model relates to the field of deep desalination technology in water treatment, and in particular to a dual-membrane electro-deionization device. Background Technology

[0002] Electrodeionization (EDI) technology has been widely used in the deep desalination of high-purity water required by industries such as power, electronics, chemicals, pharmaceuticals, and papermaking. Compared with traditional mixed-bed desalination, EDI has significant advantages such as environmental friendliness, high automation, and low operating costs, leading to its increasing application. Traditional EDI is a product of a combination of electrodialysis and ion exchange. While this technology offers good treatment results, it requires the use of a large number of specialized ion exchange membranes, resulting in high equipment costs, complex structures, and difficult maintenance.

[0003] A previous patent (ZL201010566567.7) disclosed a chamberless EDI technology, requiring only two cation exchange membranes per unit and containing only three compartments: an anode chamber, a cathode chamber, and a resin chamber. Clearly, compared to traditional EDI technology, this chamberless EDI technology offers significant advantages such as simpler structure, lower cost, and easier maintenance. The chamberless EDI technology employs alternating treatment and electroregeneration operations. During regeneration, the electric field direction within the resin chamber is perpendicular to the water flow direction. Cations and anions migrate along and against the electric field direction, respectively. Cations can pass through the cation exchange membrane near the cathode and enter the cathode chamber, then are discharged with the cathode water. Anions, however, are blocked by the cation exchange membrane near the anode and accumulate near the interface between the cation exchange membrane and the resin, affecting the electroregeneration efficiency and the quality of the treated water. Furthermore, the anode and cathode chambers of the aforementioned EDI technology without a concentration chamber still require the use of electrolyte, and a dedicated electrolyte storage tank and circulation pump must be configured. The system is complex and consumes chemical reagents, posing environmental problems.

[0004] A previous patent (ZL201110048386.X) disclosed an EDI (MFEDI) technology that does not require the use of an ion exchange membrane. Compared with traditional EDI, MFEDI has many advantages such as low equipment cost, simple structure, convenient maintenance, high water recovery rate, and low energy consumption. However, in this technology, the direction of the electric field during the electroregeneration process is either the same as or opposite to the direction of the regenerated water flow. This can cause reverse electromigration of anions or cations during the electroregeneration process, which is detrimental to regeneration and will also affect the electroregeneration efficiency and the quality of the subsequent product water. Utility Model Content

[0005] In order to overcome the problems existing in the background technology, this utility model provides a dual-membrane electro-deionization device for deep desalination of industrial high-purity water.

[0006] The technical solution adopted in this utility model is:

[0007] The device contains three compartments: a cathode compartment, a resin compartment, and an anode compartment. The cathode compartment and the resin compartment are separated by a cation exchange membrane, and the anode compartment and the resin compartment are separated by an anion exchange membrane. The distance between the cation exchange membrane and the anion exchange membrane is 10-100 cm.

[0008] The cathode chamber is mainly composed of a cathode chamber end plate and a cation exchange membrane. A groove is provided on the inner side of the cathode chamber end plate, and multiple protruding supports are provided on the groove. The net distance between adjacent protruding supports is 5-20mm. The mesh cathode is placed between the protruding supports on the groove of the cathode chamber end plate and the cation exchange membrane and is in close contact with both. During electroregeneration, the electrode water passes through the gaps between the protruding supports and the gaps in the mesh cathode.

[0009] The anode chamber is mainly formed by an anode chamber end plate and an anion exchange membrane. A groove is provided on the inner side of the anode chamber end plate, and multiple protruding supports are provided on the groove. The net distance between adjacent protruding supports is 5-20mm. The mesh anode is placed between the protruding supports on the groove of the anode chamber end plate and the anion exchange membrane and is in close contact with both. During electroregeneration, the electrode water passes through the gaps between the protruding supports and the gaps of the mesh anode.

[0010] The resin chamber is mainly composed of cation exchange membranes and anion exchange membranes on the left and right sides, an upper resin retainer on the upper side, a lower resin retainer on the lower side, and the front and rear side walls of the frame. The upper and lower resin retainers are also placed inside the frame. The resin chamber is filled with a mixture of cation and anion resins, and the mixture of cation and anion resins is fully compressed during filling.

[0011] The frame can be a single unit or assembled from multiple units. When multiple units are assembled together, adjacent frames are sealed with a sealant. The frame and the cathode chamber end plate are fixedly connected by bolts and fasteners and sealed with sealant A. The frame and the anode chamber end plate are fixedly connected by bolts and fasteners and sealed with sealant B.

[0012] The cathode chamber end plate is provided with an upper left interface and an upper right interface at the top. The upper left interface is used to introduce the influent to be treated or to discharge the regeneration water effluent from the resin chamber. The upper right interface is used to discharge the electrode water effluent. The cathode chamber end plate is provided with a lower left interface and a lower right interface at the bottom. The lower left interface is used to introduce the electrode water influent. The lower right interface is used to discharge the product water or to introduce the regeneration water influent from the resin chamber.

[0013] The top of the frame is provided with an inlet / regeneration outlet water channel and an electrode chamber outlet water channel. The inlet / regeneration outlet water channel is connected to the upper side of the upper resin retainer, and the electrode chamber outlet water channel is connected to the upper ends of the anode chamber and cathode chamber. The bottom of the frame is provided with a product water / regeneration inlet water channel and an electrode chamber inlet water channel. The product water / regeneration inlet water channel is connected to the lower side of the lower resin retainer, and the electrode chamber inlet water channel is connected to the lower ends of the anode chamber and cathode chamber.

[0014] The upper left interface is connected to the water inlet / regenerated water outlet channel, and the lower right interface is connected to the water production / regenerated water inlet channel.

[0015] The lower left interface is connected to the water inlet channel of the polar chamber, and the upper right interface is connected to the water outlet channel of the polar chamber.

[0016] Both the upper and lower resin traps are insulating plates with multiple trapezoidal slits and multiple reinforcing ribs. The narrowest part of the slits is 0.20-0.35mm, which is used to effectively trap resin particles, but allows water to flow smoothly in and out.

[0017] The beneficial effects of this utility model are:

[0018] 1) Significantly improves electro-regeneration efficiency and product water quality;

[0019] 2) During electroregeneration, the regenerated water flowing through the resin chamber is used as the electrode water, eliminating the need to consume electrolyte solution. This avoids environmental problems and eliminates the need for an electrode water circulation pump, simplifying the system and operation management.

[0020] This invention is applicable to the deep desalination of industrial high-purity water, and also to water containing Ni. 2+ Advanced treatment of wastewater with low concentrations of heavy metal ions. Attached Figure Description

[0021] Figure 1 This is a front view of the device of this utility model;

[0022] Figure 2 This is a cross-sectional view of the device of this utility model (AA).

[0023] Figure 3 This is a cross-sectional view of the device BB of this utility model.

[0024] In the diagram: 1. Cathode chamber end plate, 2. Upper left interface, 3. Lower left interface, 4. Upper right interface, 5. Lower right interface, 6. Bolt fastener, 7. Cathode chamber, 8. Resin chamber, 9. Mesh cathode, 10. Cation exchange membrane, 11. Seal A, 12. Upper resin retention component, 13. Lower resin retention component, 14. Frame, 15. Seal B, 16. Anode chamber end plate, 17. Anion exchange membrane, 18. Mesh anode, 19. Anode chamber, 20. Inlet / regeneration outlet channel, 21. Electrode chamber inlet channel, 22. Electrode chamber outlet channel, 23. Product water / regeneration inlet channel. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] like Figures 1-3 As shown, the device contains only one pair of cation and anion exchange membranes. The device includes three compartments: a cathode compartment 7, a resin compartment 8, and an anode compartment 19. The resin compartment 8 is located between the cathode compartment 7 and the anode compartment 19. The cathode compartment 7 and the resin compartment 8 are separated by a cation exchange membrane 10, and the anode compartment 19 and the resin compartment 8 are separated by an anion exchange membrane 17. The distance between the two membranes, the cation exchange membrane 10 and the anion exchange membrane 17, is 10-100 cm.

[0027] like Figure 2 As shown, the cathode chamber 7 is mainly formed by the cathode chamber end plate 1 and the cation exchange membrane 10. A groove is opened on the inner side of the cathode chamber end plate 1, and multiple protruding supports are provided on the groove. The multiple protruding supports are distributed at intervals, and the net distance between adjacent protruding supports is 5-20mm. The mesh cathode 9 is placed between the protruding supports on the groove of the cathode chamber end plate 1 and the cation exchange membrane 10 and is in close contact with both. The protruding supports and the mesh cathode 9 are in contact on one side, and the mesh cathode 9 is in contact with the cation exchange membrane 10 on the other side. During electroregeneration, the electrode water passes through the gaps between the protruding supports and the gaps in the mesh cathode 9.

[0028] like Figure 2 As shown, the anode chamber 19 is mainly enclosed by an anode chamber end plate 16 and an anion exchange membrane 17. A groove is formed on the inner side of the anode chamber end plate 16, and multiple protruding supports are provided on the groove. The multiple protruding supports are distributed at intervals, and the net distance between adjacent protruding supports is 5-20mm. The mesh anode 18 is placed between the protruding supports on the groove of the anode chamber end plate 16 and the anion exchange membrane 17 and is in close contact with both. The protruding supports and the mesh anode 18 are in contact on one side, and the mesh anode 18 is in contact with the anion exchange membrane 17 on the other side. During electro-regeneration, the electrode water passes through the gaps between the protruding supports and the gaps between the mesh anode 18.

[0029] like Figure 2As shown, the resin chamber 8 is mainly composed of cation exchange membranes 10 and anion exchange membranes 17 on the left and right sides, an upper resin retainer 12 on the upper side, a lower resin retainer 13 on the lower side, and the front and rear side walls of the frame 14. The upper resin retainer 12 and the lower resin retainer 13 are also placed inside the frame 14. The upper resin retainer 12, the lower resin retainer 13, the cation exchange membrane 10, and the anion exchange membrane 17 are fixedly arranged through the frame 14. The resin chamber 8 is filled with a mixture of cation and anion exchange resins, which are fully compressed during filling.

[0030] The frame 14 can be a single piece or assembled from multiple pieces. When multiple frames are assembled together, the adjacent frames are sealed with a sealant. The frame 14 and the cathode chamber end plate 1 are fixedly connected by bolts and fasteners 6 and sealed by sealant A 11. The frame 14 and the anode chamber end plate 16 are fixedly connected by bolts and fasteners 6 and sealed by sealant B 15.

[0031] like Figure 1 As shown, the top left interface 2 and the top right interface 4 are respectively provided on the front and rear sides of the top of the cathode chamber end plate 1. The top left interface 2 is used to introduce the influent to be treated or to discharge the regeneration water outlet of the resin chamber 8, and the top right interface 4 is used to discharge the electrode water outlet.

[0032] like Figure 2 As shown, the bottom of the cathode chamber end plate 1 is provided with a lower left interface 3 and a lower right interface 5 on the front and rear sides. The lower left interface 3 is used to introduce electrode water inlet water, and the lower right interface 5 is used to discharge product water or introduce regeneration water inlet water into the resin chamber 8.

[0033] The top of the frame 14 is provided with an inlet / regeneration outlet water channel 20 and an electrode chamber outlet water channel 22. The inlet / regeneration outlet water channel 20 is connected to the upper side of the upper resin retainer 12 through a corresponding small hole, and the electrode chamber outlet water channel 22 is connected to the upper end of the anode chamber 19 and the cathode chamber 7 through a corresponding small hole.

[0034] The bottom of the frame 14 is provided with a water production / regeneration inlet channel 23 and an electrode chamber inlet channel 21. The water production / regeneration inlet channel 23 is connected to the lower side of the lower resin retainer 13 through corresponding small holes. The electrode chamber inlet channel 21 is connected to the lower end of the anode chamber 19 and the cathode chamber 7 through corresponding small holes.

[0035] like Figure 2 and Figure 3As shown, the upper left interface 2 is connected to the inlet / regeneration outlet channel 20, and the lower right interface 5 is connected to the product water / regeneration inlet channel 23. This allows the product water obtained during the electro-regeneration process to be used as the regeneration water. The regeneration water enters the product water / regeneration inlet channel 23 from the lower right interface 5, then enters the resin chamber 8 through the lower resin retainer 13, and then enters the inlet / regeneration outlet channel 20 through the upper resin retainer 12, and finally exits from the upper left interface 2.

[0036] like Figure 2 and Figure 3 As shown, the lower left interface 3 is connected to the electrode chamber inlet channel 21, and the upper right interface 4 is connected to the electrode chamber outlet channel 22. This allows the regenerated water flowing through the resin chamber 8 to be used as the electrode water during electro-regeneration. The electrode water enters from the lower left interface 3 and then flows into the bottom of the cathode chamber 7 and anode chamber 19 through the electrode chamber inlet channel 21. Due to the electric field, the electrode water flowing into the cathode chamber 7 and anode chamber 19 flows out from their respective tops to the electrode chamber outlet channel 22 and is finally discharged from the upper right interface 4.

[0037] During processing, no water flows through the cathode chamber 7 and the anode chamber 19, and all the water to be treated flows through the resin chamber 8. The water to be treated enters the inlet / regeneration outlet channel 20 from the upper left interface 2, then enters the resin chamber 8 through the upper resin retainer 12, and then enters the product water / regeneration inlet channel 23 through the lower resin retainer 13, and finally exits from the lower right interface 5.

[0038] like Figure 2 As shown, both the upper resin trap 12 and the lower resin trap 13 are insulating plates with multiple trapezoidal slits and multiple reinforcing ribs. The width of the narrowest part of the slit is 0.20-0.35mm, which is used to effectively trap resin particles, but allows water to flow smoothly into and out of the resin chamber 8.

[0039] The alternating operation process of processing and electroregeneration under this utility model device is as follows:

[0040] The dual-film electro-deionization device is a dual-film electro-deionization device with a cathode chamber 7, a resin chamber 8, and an anode chamber 19. The cathode chamber 7 and the anode chamber 19 are located on opposite sides of the resin chamber 8. The process employs alternating treatment and electro-regeneration operations.

[0041] During treatment, no water flows through the cathode chamber 7 and the anode chamber 19; all the water to be treated flows only through the resin chamber 8.

[0042] During electroregeneration, the permeate obtained during the treatment process is used as the regeneration water for resin chamber 8. The regeneration water flows continuously through resin chamber 8 in the opposite direction to that during the treatment process. The regeneration effluent after flowing through resin chamber 8 is then used entirely or partially as electrode water. The electrode water flows continuously through cathode chamber 7 and anode chamber 19. At the same time as the electrode water flows continuously through cathode chamber 7 and anode chamber 19, a direct current with a current density of 50 to 200 A / m2 is applied. The direction of the electric field in resin chamber 8 is perpendicular to the direction of water flow.

[0043] This effectively overcomes the reverse electromigration problem, where either anions or cations migrate in the regeneration process of conventional membrane-free electrodeionization technology, which is detrimental to resin regeneration. Moreover, impurity ions in the resin can not only be released into the regeneration water flow as in conventional membrane-free electrodeionization technology, but can also migrate into the cathode and anode chambers for further discharge, thereby significantly improving the electroregeneration efficiency of the exhausted resin and the quality of the subsequent product water. During the electroregeneration process, the regeneration water flowing through resin chamber 8 continuously receives the regenerated impurity ions, resulting in an average conductivity of tens to hundreds of μs / cm for the regeneration effluent from resin chamber 8. Therefore, the regeneration effluent from resin chamber 8 has good conductivity, and this water also has sufficient water pressure. By replacing the electrolyte solution in the previous patent ZL201010566567.7 as the electrode water, environmental problems can be avoided, the electrode water circulation pump can be eliminated, the system can be simplified, and operation and management can be facilitated.

[0044] Example:

[0045] Water with an electrical conductivity of approximately 5 μS / cm is used Figures 1-3 The apparatus shown is used for treatment. The effective area of ​​both the anion and cation exchange membranes is 120 cm², and the distance between the two membranes is 30 cm. The resin chamber is filled with a mixed anion and cation exchange resin. Treatment and electroregeneration are performed alternately. The treatment time and electroregeneration time for each cycle are 300 min and 20 min, respectively. The treatment flow rate and electroregeneration flow rate are 720 L / h and 250 L / h, respectively. During electroregeneration, the current density is 150 A / m², and the average voltage is approximately 300 V. After stable operation, the conductivity of the product water is 0.056-0.060 μS / cm, the water recovery rate is 97.7%, and the DC power consumption is approximately 0.05 kWh / m². 3 .

[0046] The above specific embodiments are used to explain and illustrate the present utility model, and are not intended to limit the present utility model. Any modifications and changes made to the present utility model within the spirit and scope of the claims shall fall within the protection scope of the present utility model.

[0047] The above description is only a preferred embodiment of the present utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included in the scope of the present utility model patent application.

Claims

1. A dual-membrane electro-deionization device, characterized in that: The device contains three compartments: a cathode compartment (7), a resin compartment (8), and an anode compartment (19). The cathode compartment (7) and the resin compartment (8) are separated by a cation exchange membrane (10), and the anode compartment (19) and the resin compartment (8) are separated by an anion exchange membrane (17). The distance between the cation exchange membrane (10) and the anion exchange membrane (17) is 10-100 cm.

2. The dual-membrane electro-deionization device according to claim 1, characterized in that: The cathode chamber (7) is mainly formed by the cathode chamber end plate (1) and the cation exchange membrane (10). A groove is provided on the inner side of the cathode chamber end plate (1), and multiple protruding supports are provided on the groove. The net distance between adjacent protruding supports is 5-20mm. The mesh cathode (9) is placed between the protruding supports on the groove of the cathode chamber end plate (1) and the cation exchange membrane (10) and is in close contact with both. During electroregeneration, the electrode water passes through the gap between the protruding supports and the gap in the mesh cathode (9).

3. The dual-membrane electro-deionization device according to claim 1, characterized in that: The anode chamber (19) is mainly formed by the anode chamber end plate (16) and the anion exchange membrane (17). A groove is provided on the inner side of the anode chamber end plate (16), and multiple protruding supports are provided on the groove. The net distance between adjacent protruding supports is 5-20mm. The mesh anode (18) is placed between the protruding supports on the groove of the anode chamber end plate (16) and the anion exchange membrane (17) and is in close contact with both. During electroregeneration, the electrode water passes through the gap between the protruding supports and the gap between the mesh anode (18).

4. The dual-membrane electro-deionization device according to claim 2, characterized in that: The resin chamber (8) is mainly composed of cation exchange membranes (10) and anion exchange membranes (17) on the left and right sides, an upper resin retainer (12) on the upper side, a lower resin retainer (13) on the lower side, and the front and rear side walls of the frame (14). The upper resin retainer (12) and the lower resin retainer (13) are also placed inside the frame (14). The resin chamber (8) is filled with a mixture of cation and anion resins. During filling, the mixture of cation and anion resins is fully compressed.

5. The dual-membrane electro-deionization device according to claim 4, characterized in that: The frame (14) can be a single piece or assembled from multiple pieces. When multiple pieces are assembled together, the adjacent frames are sealed with a seal. The frame (14) and the cathode chamber end plate (1) are fixedly connected by bolts and fasteners (6) and sealed by seal A (11). The frame (14) and the anode chamber end plate (16) are fixedly connected by bolts and fasteners (6) and sealed by seal B (15).

6. The dual-membrane electro-deionization device according to claim 4, characterized in that: The cathode chamber end plate (1) is provided with an upper left interface (2) and an upper right interface (4) at the top. The upper left interface (2) is used to introduce the influent to be treated or to discharge the regeneration water outlet of the resin chamber (8). The upper right interface (4) is used to discharge the electrode water outlet. The bottom of the cathode chamber end plate (1) is provided with a lower left interface (3) and a lower right interface (5). The lower left interface (3) is used to introduce electrode water inlet water, and the lower right interface (5) is used to discharge product water or introduce regeneration water inlet water into the resin chamber (8).

7. The dual-membrane electro-deionization device according to claim 6, characterized in that: The top of the frame (14) is provided with an inlet / regeneration outlet channel (20) and an electrode chamber outlet channel (22). The inlet / regeneration outlet channel (20) is connected to the upper side of the upper resin retainer (12), and the electrode chamber outlet channel (22) is connected to the upper end of the anode chamber (19) and the cathode chamber (7). The bottom of the frame (14) is provided with a water production / regeneration water inlet channel (23) and an electrode chamber water inlet channel (21). The water production / regeneration water inlet channel (23) is connected to the lower side of the lower resin retainer (13), and the electrode chamber water inlet channel (21) is connected to the lower end of the anode chamber (19) and the cathode chamber (7).

8. The dual-membrane electro-deionization device according to claim 7, characterized in that: The upper left interface (2) is connected to the water inlet / regenerated water outlet channel (20), and the lower right interface (5) is connected to the water production / regenerated water inlet channel (23); The lower left interface (3) is connected to the water inlet channel (21) of the polar chamber, and the upper right interface (4) is connected to the water outlet channel (22) of the polar chamber.

9. The dual-membrane electro-deionization device according to claim 4, characterized in that: The upper resin trap (12) and lower resin trap (13) are both insulating plates with multiple trapezoidal slits and multiple reinforcing ribs. The width of the narrowest part of the slit is 0.20-0.35mm, which is used to effectively trap resin particles but allow water to flow smoothly in and out.

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