Capacitive desalination device

Abstract

The application belongs to the field of industrial water treatment and relates to a capacitive desalination device. Through the structural design of a cylindrical shell combined with an integral injection-molded end plate and a carbon-based electrode assembly, in cooperation with a dispersion plate with controllable flow guide channels and uniformly staggered water guide holes, uniform distribution and efficient water collection of the inlet water are realized. The water flow path is optimized to ensure sufficient flow through the electrode gap, and under the driving of the electric field, ions in the water are efficiently removed. The regeneration process does not require chemical reagents and can be completed through electrode short-circuiting, avoiding secondary pollution. The module has strong adaptability to high-salt raw water, and significantly improves the operation stability, energy efficiency ratio and engineering applicability of the capacitive desalination system.

Description

Technical Field

[0001] This invention belongs to the field of industrial water treatment, and in particular relates to a capacitor desalination device. Background Technology

[0002] Capacitive desalination is a water treatment technology that desalinates water by driving ions to migrate towards a carbon electrode using an electrostatic field, forming an electric double layer. This technology utilizes carbon-based electrodes to adsorb salts in the water, and regeneration requires only discharge without chemical reagents, avoiding the high energy consumption and secondary pollution problems of traditional desalination methods. Capacitive desalination technology is widely used in seawater desalination, industrial water treatment, agricultural water, and domestic water purification, offering advantages such as low energy consumption, high efficiency, and no secondary pollution. However, existing capacitive desalination modules generally suffer from uneven water distribution and turbulent flow patterns, resulting in low electrode surface utilization and limited desalination efficiency. Furthermore, under high-salinity influent conditions, unreasonable ion migration paths can easily cause local concentration polarization, affecting cycle stability and desalination rate. In addition, traditional module designs lack effective control over the direction and velocity of influent flow, making it difficult to balance high throughput and high desalination rate, thus hindering the widespread application of capacitive desalination systems in large-scale water treatment scenarios. Summary of the Invention

[0003] Based on the above background, in order to improve the effect of capacitor desalination, the present invention proposes a capacitor desalination device, comprising:

[0004] A cylindrical shell includes a first hollow cylindrical shell and a second hollow cylindrical shell, wherein the second hollow cylindrical shell is fitted into the first hollow cylindrical shell, and the radius r1 of the first hollow cylindrical shell is greater than the radius r2 of the second hollow cylindrical shell;

[0005] The cavity for accommodating the electrode assembly and the water channel are composed of a first hollow cylindrical shell and a second hollow cylindrical shell, and multiple water guide holes are uniformly arranged in the water guide channel.

[0006] A circular dispersion plate is set on the end face of a cylindrical shell. The dispersion plate has a flow channel connected to the water inlet. The flow channel adopts a radial flow channel design, extending radially from the center to the periphery, which is used to evenly distribute the water into the flow channel. The water flow is guided to the electrode gap through multiple water guide holes in the flow channel.

[0007] The two sealed end plates are located on the side of the circular dispersion plate away from the cylindrical shell, and on the other side of the cylindrical shell; the two sealed end plates are provided with electrode heads for energizing the electrode assembly and water inlet or outlet;

[0008] The internal carbon-based material component, located within the cavity, includes multiple concentrically arranged carbon-based electrode assemblies and supporting filling accessories. The electrode assemblies are arranged in a ring array around the central channel, and an electrode gap is formed between adjacent electrode plates through which water flows.

[0009] The two end sealing plates, the circular dispersion plate and the cylindrical shell are connected by connectors; multiple bolt connection mechanisms are set around the circumference of the two end sealing plates near the outer edge, and the connection is achieved by high-strength stainless steel bolts to ensure structural stability.

[0010] The water guide holes are evenly distributed on the side wall of the second hollow cylindrical shell, along the axial direction, and adjacent groups of water guide holes are staggered. The water guide holes adopt a circular hole structure, and the hole diameter is set according to the water flow rate, the number of water guide holes and the water flow velocity.

[0011] The capacitor desalination device has the functions of uniform water distribution and water collection. The water to be treated enters the electrode gap after being guided by the dispersion plate. Under the action of the electric field, ion migration and adsorption are realized, and the deionization process is completed.

[0012] The electrode assembly adopts a fixed structure with positioning at both ends. An annular positioning groove is set inside the second hollow cylindrical shell, and the two ends of the electrode assembly are embedded in the positioning groove to achieve axial positioning. All positive plates are connected in parallel to one electrode head through copper conductive busbars, and all negative plates are connected in parallel to another electrode head through another set of copper conductive busbars.

[0013] As can be seen from the above technical solution, the present invention proposes a capacitor desalination device. By adopting a structural design that combines a cylindrical shell with an integrated injection-molded end plate and a carbon-based electrode assembly, along with a dispersion plate with controllable flow channels and uniformly staggered water guide holes, it achieves uniform water distribution and efficient water collection. The water flow path is optimized to ensure sufficient flow through the electrode gaps, and ions in the water are efficiently removed under the drive of an electric field. The regeneration process does not require chemical reagents and can be completed simply by short-circuiting the electrodes, avoiding secondary pollution. This module has strong adaptability to high-salinity raw water, significantly improving the operational stability, energy efficiency ratio, and engineering applicability of the capacitor desalination system. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure of the capacitor desalination device proposed in this invention;

[0016] Figure 2 This is a side view of the capacitor desalination device proposed in this invention;

[0017] Figure 3This is a schematic diagram of the working principle of the capacitor desalination device proposed in this invention;

[0018] Figure 4 These are schematic diagrams of the front and back sides of the end plate of the capacitor desalination device proposed in this invention.

[0019] Figure 5 This is a schematic diagram of another form of the end plate of the capacitor desalination device proposed in this invention;

[0020] Figure 6 This is a schematic diagram of the dispersion plate of the capacitor desalination device proposed in this invention;

[0021] Figure 7 This is a schematic diagram of the flow channel configuration of the dispersion plate in the capacitor desalination device proposed in this invention.

[0022] 1 is the shell, 2 is the end plate, 21 is the end plate, 3 is the dispersion plate, 4 is the inlet, 5 is the electrode head, 6 is the connector, 7 is the outlet, 8 is the fiberglass shell, 9 is the flow channel, 61 is the bolt, 10 is the ribbed surface, and 101 is the ribbed surface. Detailed Implementation

[0023] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0024] like Figure 1 , Figure 2 , Figure 3 As shown, a capacitor desalination device includes:

[0025] The cylindrical shell 1 includes a first hollow cylindrical shell and a second hollow cylindrical shell, wherein the second hollow cylindrical shell is fitted into the first hollow cylindrical shell, and the radius r1 of the first hollow cylindrical shell is greater than the radius r2 of the second hollow cylindrical shell.

[0026] The cavity for accommodating the electrode assembly and the water channel are composed of a first hollow cylindrical shell and a second hollow cylindrical shell, and multiple water guide holes are uniformly arranged in the water guide channel.

[0027] A circular dispersion plate 3 is set on the end face of a cylindrical shell. The dispersion plate 3 has a flow channel 9 connected to the water inlet 4. The flow channel adopts a radial flow channel design, which extends radially from the center to the periphery. It is used to evenly distribute the water into the flow channel and guide the water flow to the electrode gap through multiple water guide holes in the flow channel.

[0028] The two sealed end plates 2 and 21 are located on the side of the circular dispersion plate away from the cylindrical shell, and the other is located on the other side of the cylindrical shell; the two sealed end plates are provided with an electrode head 5 for energizing the electrode assembly, a water inlet 4 or a water outlet 7.

[0029] The internal carbon-based material component, located within the cavity, includes multiple concentrically arranged carbon-based electrode assemblies and supporting filling accessories. The electrode assemblies are arranged in a ring array around the central channel, and an electrode gap is formed between adjacent electrode plates to allow water to flow through.

[0030] like Figure 1 , Figure 2 , Figure 5 As shown, the two end sealing plates, the circular dispersion plate 3 and the cylindrical shell are connected by connectors 6. Multiple bolt connection mechanisms are set around the circumference of the two end sealing plates near the outer edge, and the connection is achieved by high-strength stainless steel bolts to ensure structural stability.

[0031] In one specific embodiment, the water guide holes are evenly distributed on the side wall of the second hollow cylindrical shell along the axial direction; multiple sets can be set, for example, 10 to 20 sets, depending on actual needs; adjacent sets of water guide holes are staggered to ensure that the water flow can fully cover the water inlet of the electrode assembly and avoid local water flow blind spots.

[0032] The water guide hole adopts a circular hole structure, and the hole diameter is set according to the water flow rate, the number of water guide holes and the water flow velocity. In actual design, the hole diameter is 8-12mm, and the total flow area of ​​the water guide hole is not less than 1.2 times the cross-sectional area of ​​the water guide channel to ensure that the pressure drop does not exceed 0.05MPa when the water flows through, and to avoid uneven water distribution caused by excessive local flow velocity.

[0033] like Figure 4 As shown, the surface of end plate 2 is a ribbed surface 10. Flow channels 9 can be provided in end plate 2, or they can be omitted. Figure 5 As shown.

[0034] Specifically, the radius of the circular dispersion plate is r3, where r1 > r3 > r2. In one specific embodiment, the circular dispersion plate 3 is integrally injection molded from PP material, which has good corrosion resistance and mechanical strength.

[0035] In one specific embodiment, the connector is a bolt 61.

[0036] like Figure 4 As shown, the flow channel 9 of the circular dispersion plate 3 is a plurality of straight flow channels.

[0037] The flow channel 9 of the circular dispersion plate can also be a curved channel; such as... Figure 7As shown, the curved flow channels are available in multiple wheel-shaped, lotus-shaped, curved, chrysanthemum-shaped, ruler-shaped, and sunflower-shaped configurations to adapt to different water quality conditions. For example, when the influent contains a high amount of suspended solids, using a large-aperture spiral flow channel can reduce the risk of clogging. When extremely high water distribution uniformity is required, a non-uniformly distributed channel layout optimized by CFD simulation can be used. For instance, when the influent contains a high amount of suspended solids (suspended solids content > 6 mg / L), using a large-aperture spiral flow channel (aperture diameter 15-20 mm, pitch 30-40 mm) can reduce the risk of clogging, and the flow area of ​​the channel increases by 30% compared to conventional designs. When extremely high water distribution uniformity is required (water distribution uniformity error ≤ 5%), a non-uniformly distributed channel layout optimized by CFD simulation is used, with the channel aperture dynamically adjusted according to the water flow path (8-15 mm) to ensure that the water flow is evenly distributed to the water guiding channel after passing through the flow channel.

[0038] like Figure 6 As shown, in a specific embodiment, there are two electrode heads 5, which serve as backups for each other; they are symmetrically arranged on both sides of the center of the end plate. Optionally, the electrode heads 5 are made of copper alloy and have a nickel-plated surface, which provides good conductivity and corrosion resistance.

[0039] In one specific embodiment, the first hollow cylindrical shell and the second hollow cylindrical shell are made of fiberglass.

[0040] In one specific embodiment, the two end plates are disc-shaped integral injection molded parts.

[0041] Specifically, the electrode assembly adopts a fixed structure with positioning at both ends. An annular positioning groove is set inside the second hollow cylindrical shell, and the two ends of the electrode assembly are embedded in the positioning groove to achieve axial positioning. All positive electrode plates are connected in parallel to one electrode head 5 through copper conductive busbars, and all negative electrode plates are connected in parallel to another electrode head 5 through another set of copper conductive busbars. The connection between the conductive busbars and the electrode plates is riveted, with a contact resistance ≤5mΩ, ensuring that the current is evenly distributed to each electrode plate and avoiding localized heating. The electrode assembly uses activated carbon fiber composite electrodes; those skilled in the art can choose other fixing methods, which are not listed here.

[0042] like Figure 3 As shown, the working principle of the capacitor desalination device proposed in this invention includes a water production process and a regeneration process.

[0043] During the water production process, the electrode assembly is powered by the electrode head 5 on the sealed end plates 2 and 21. That is, a constant voltage power supply mode is used to provide a power supply voltage U1 to the electrode head 5. After the electrode assembly is charged, the surface of the positive electrode plate is filled with positive charge and the surface of the negative electrode plate is filled with negative charge, forming a uniform electric field distribution. The water to be treated enters the circular dispersion plate 3 through the water inlet 4 of the water inlet end plate, and is evenly distributed to the water guiding channel through the guide channel 9 (for example, adopting a radial design, extending radially from the center to the periphery), avoiding excessive local flow velocity or the formation of dead zones. Water flows smoothly within the water guiding channel and evenly enters the gaps between multiple electrode components through the water guiding holes on the second hollow cylindrical shell. During the process of passing through the electrode gaps (e.g., water flow velocity of 0.05-0.1 m / s, residence time of 20-30 s), the electric field force causes cations in the solution (such as Na+, Ca2+, Fe2+, Fe3+, etc.) to migrate towards the negative electrode plate and be adsorbed on its surface, while anions (such as Cl-, SO32-, SO42-, etc.) migrate towards the positive electrode plate and be adsorbed on its surface. Charged particles in the water are efficiently adsorbed by the electrode surfaces, achieving water deionization. The deionized water collects at the outlet end and flows out through the outlet port of the outlet plate, completing the water purification process.

[0044] Regeneration Process: After the water production process has been running for a certain period, such as 30 to 60 minutes, the adsorption capacity of the electrode assembly reaches saturation, and the regeneration program is initiated. The regeneration process requires no chemical reagents. The electrode assembly is short-circuited via a switching circuit. Specifically, a bidirectional switch is installed in the power supply circuit. During regeneration, the switch directly short-circuits the positive and negative plates through a wire, forming a discharge circuit. The short-circuit time is 5-10 minutes. After short-circuiting, the anions and cations adsorbed on the electrode surface undergo a neutralization reaction, detaching from the electrode surface and entering the water to form wastewater. The wastewater flows in the opposite direction to the water production flow. Driven by the concentration gradient and water flow, it flows from the electrode gap into the guide channel, then through the flow channel of the circular dispersion plate to the inlet of the inlet plate, and finally enters the wastewater collection device through a branch pipe, completing the regeneration process. After regeneration, the switching circuit restores power, and the device re-enters the water production state.

[0045] Through experimental testing, CFD simulation analysis, and comparison with existing technologies, the technical effects of this device are as follows:

[0046] 1) Improved uniform water distribution: The radial flow channel and staggered water guide hole design, verified by CFD simulation, show that the uniformity error of the flow velocity distribution within the electrode gap is ≤3.6%, far superior to traditional devices. Experimental tests show that the water flow velocity fluctuation range at the inlet and outlet is ≤±0.01m / s, with no obvious dead zones, ensuring the stability of the desalination process.

[0047] 2) It has high-efficiency desalination performance. Experimental tests were conducted on raw water with different salt contents. When the raw water salt content was 500 mg / L, the salt content after treatment by the desalination device in this solution was less than 60 mg / L; when the raw water salt content was 1000 mg / L, the salt content after treatment by the desalination device in this solution was less than 95 mg / L. Compared with the existing capacitor desalination device, the desalination rate of this device is improved by 15-20%, mainly due to the uniform water distribution design, optimized electrode structure and efficient electric field distribution.

[0048] 3) Regeneration performance: The regeneration process has a short short-circuit time, for example, 5-15 minutes, with a regeneration rate ≥95% (the electrode adsorption capacity recovers to more than 95% of the initial capacity after regeneration). Wastewater discharge is only 4.3-8.2% of the total water production, lower than traditional desalination technologies. Experiments have verified that after 500 water production regeneration cycles, the desalination rate of the device remains above 88%, and the electrode components show no significant degradation.

[0049] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0050] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0051] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A capacitor desalination device, characterized in that, The capacitor desalination device includes: A cylindrical shell (1) includes a first hollow cylindrical shell and a second hollow cylindrical shell. The second hollow cylindrical shell is fitted into the first hollow cylindrical shell. The first hollow cylindrical shell and the second hollow cylindrical shell together form a cavity for accommodating the electrode assembly and a water channel. A water channel is provided in the water channel. The radius r1 of the first hollow cylindrical shell is greater than the radius r2 of the second hollow cylindrical shell. A circular dispersion plate (3) is set on the end face of a cylindrical shell. The dispersion plate is provided with a guide channel (9) connected to the water inlet. The guide channel adopts a radial channel design, extending radially from the center to the periphery, which is used to evenly distribute the water into the guide channel. Two sealing end plates (2, 21) are provided, one on the side of the circular dispersion plate away from the cylindrical shell and the other on the other side of the cylindrical shell. The two sealing end plates are provided with an electrode head (5) for energizing the electrode assembly, a water inlet (4) or a water outlet (7). The internal carbon-based material component is located in the cavity and includes multiple concentrically arranged carbon-based electrode assemblies and supporting filling accessories. The electrode assemblies are arranged in a ring array around the central channel, and an electrode gap is formed between adjacent electrode plates for water to flow through. The two sealing end plates (2, 21), the circular dispersion plate (3) and the cylindrical shell (1) are connected by a connector (6). The electrode assembly adopts a fixed structure with positioning at both ends. An annular positioning groove is provided on the inner side of the second hollow cylindrical shell, and the two ends of the electrode assembly are embedded in the positioning groove to achieve axial positioning. Multiple sets of water guide holes are evenly arranged on the side wall of the second hollow cylindrical shell, distributed along the axial direction, with adjacent sets of water guide holes arranged in an alternating pattern.

2. The capacitor desalination device according to claim 1, wherein the radius of the circular dispersion plate is r3, where r1 > r3 > r2.

3. In the capacitor desalination device according to claim 1, the flow channel of the circular dispersion plate is a plurality of straight channels.

4. In the capacitor desalination device according to claim 1, the flow channel of the circular dispersion plate is a curved flow channel.

5. The capacitor desalination device according to claim 4, wherein the curved flow channel is a plurality of wheel-shaped, lotus-shaped, curved, chrysanthemum-shaped, ruler-shaped and sunflower-shaped, to adapt to different water quality conditions.

6. The capacitor desalination device according to claim 1, wherein the number of electrode heads (5) is two, which serve as backups for each other.

7. The capacitor desalination device according to claim 1, wherein the first hollow cylindrical shell and the second hollow cylindrical shell are made of glass steel.

8. The capacitor desalination device according to claim 1, wherein the sealing end plates at both ends are disc-shaped integral injection molded parts.

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