An electrochemical softening device for recirculating cooling water and a method of using the same

Abstract

The present application relates to the technical field of water treatment, and particularly relates to a circulating cooling water electrochemical softening device and a use method thereof, which comprises a shell, a cathode plate and an anode plate arranged in the shell, the cathode plate and the anode plate are separated by a hole isolation plate to form a cathode chamber and an anode chamber; the hole isolation plate is composed of a hole fixed isolation plate, a hole movable isolation plate and an isolation film clamped between the hole fixed isolation plate and the hole movable isolation plate; an ultrasonic vibration plate is arranged in the cathode chamber, and the ultrasonic vibration plate is electrically connected with an ultrasonic generator. The device separates the cathode reaction and the anode reaction by using the isolation plate, reduces the mixing of the cathode product and the anode product, improves the utilization rate of the cathode product, and greatly improves the softening and descaling rate of the device. The three-section isolation plate design makes the structure of the device more compact and reasonable, and facilitates the maintenance of the equipment. The present application realizes the efficient and rapid regeneration of the cathode plate and the isolation film by using the reverse electrode and ultrasonic wave combination mode.

Description

Technical Field

[0001] This invention relates to the technical field of water treatment, specifically to an electrochemical softening device for circulating cooling water and its usage method. Background Technology

[0002] Circulating cooling water is an indispensable heat exchange medium in industrial production processes. Due to evaporation, the circulating water continuously concentrates, leading to scaling and other adverse effects on the entire heat exchange system. Traditionally, chemical agents are added to stabilize the water quality and mitigate scaling risks. However, this method is costly to operate and also pollutes the environment.

[0003] The principle of electrochemical softening and descaling technology is that electrolysis occurs under the action of electric current, and the cathode reaction produces a large amount of OH. - , with scale-forming ions (Ca) in water 2+ HCO3 - The reaction occurs directly in the cathode region, thereby directly reducing the concentration of scale-forming ions in the circulating cooling water and reducing the risk of scaling in the system.

[0004] Currently, although electrochemical softening and descaling technology has achieved industrial applications, it has not yet been widely adopted. This is because the technology currently suffers from problems such as low softening and descaling efficiency and scale buildup on the cathode. To address these issues, patent CN113292138A discloses an electrochemical water treatment device with descaling function, which uses a scraper to physically remove the scale covering the cathode surface. Some researchers have also improved the softening and descaling efficiency by changing the shape of the cathode electrode, such as using a multi-layer mesh cathode.

[0005] None of the above methods fundamentally solve the problem. The low softening and descaling efficiency is superficially due to the limited cathode reaction area; increasing the cathode area can improve the softening and descaling rate. However, the underlying cause of the low softening efficiency is actually the OH groups generated at the cathode. - At the same time, acidic substances are also produced at the anode, and the two will mix, which will greatly reduce the utilization rate of cathode products. This is the fundamental reason for the low efficiency of softening and descaling. Physical scraping methods can only remove the outer layer of scale on the cathode surface, and the layer of scale attached to the cathode surface cannot be removed, so the cathode reaction will still be hindered. Summary of the Invention

[0006] One of the objectives of this invention is to provide an electrochemical softening device for circulating cooling water, which improves the softening and descaling efficiency. This device separates the cathode plate and anode plate by means of an isolation plate, reducing the mixing of cathode products and anode products, thereby improving the utilization rate of cathode products. An ultrasonic vibrating plate is provided, and subsequent use of reverse polarity and ultrasonic waves can achieve rapid and effective descaling and regeneration of the cathode.

[0007] The second objective of this invention is to provide a method for using an electrochemical softening device for circulating cooling water, which has high softening efficiency and achieves rapid and effective descaling and regeneration of the cathode by using a combination of reverse polarity and ultrasonic waves.

[0008] One of the solutions adopted to achieve the objective of this invention is: a circulating cooling water electrochemical softening device, comprising a shell, a cathode plate and an anode plate disposed inside the shell, wherein the cathode plate and the anode plate are separated by a perforated partition plate to form a cathode chamber and an anode chamber;

[0009] The perforated isolation plate consists of a fixed perforated isolation plate, a movable perforated isolation plate, and an isolation membrane sandwiched between the fixed perforated isolation plate and the movable perforated isolation plate;

[0010] An ultrasonic transducer plate is installed in the cathode chamber, and the ultrasonic transducer plate is electrically connected to the ultrasonic generator.

[0011] Preferably, the perforated fixed isolation plate is fixedly connected to the shell; the perforated movable isolation plate is rotatably connected to the perforated fixed isolation plate; and an isolation membrane is sandwiched between the perforated fixed isolation plate and the perforated movable isolation plate.

[0012] Preferably, the perforated movable isolation plate is provided with an inflatable sealing ring.

[0013] Preferably, the housing is further provided with a water inlet pipe, a cathode chamber outlet and an anode chamber outlet, the lower side of the cathode chamber and the lower side of the anode chamber are both connected to the water inlet pipe, the upper side of the cathode chamber is connected to the cathode chamber outlet, and the upper side of the anode chamber is connected to the anode chamber outlet.

[0014] Preferably, the housing is further provided with a cathode chamber sludge discharge port communicating with the cathode chamber, and a helical blade rod is provided at the cathode sludge discharge port.

[0015] Preferably, the separating membrane is a cation exchange membrane.

[0016] The solution adopted to achieve the second objective of this invention is: a method of using the aforementioned circulating cooling water electrochemical softening device, comprising the following steps:

[0017] The cathode plate and anode plate are electrically connected to the negative and positive terminals of a DC power supply, respectively. When the device is started, circulating water enters the cathode chamber and anode chamber, respectively. In the cathode chamber, scale-forming ions in the water undergo a precipitation reaction, while in the anode chamber, an oxidation reaction occurs, producing highly oxidizing active chlorine components that have a bactericidal effect. The treated water is then discharged from the anode chamber and cathode chamber, respectively, resulting in treated circulating water.

[0018] After the device has been running for a certain period of time, scale will be covered on the surface of the cathode plate and the isolation membrane. Descaling and regeneration are carried out by using a combination of reverse polarity and ultrasonic waves.

[0019] Preferably, the descaling and regeneration includes the following steps:

[0020] S1: Turn off the DC power supply, connect the cathode plate to the positive terminal of the DC power supply, and connect the anode plate to the negative terminal of the DC power supply.

[0021] S2: Start the DC power supply and turn on the ultrasonic generator at the same time;

[0022] S3: After running for 1-5 minutes, turn off the ultrasonic generator and disconnect the DC power supply to complete the descaling and regeneration process.

[0023] Preferably, the ultrasonic frequency range is 20kHz to 28kHz.

[0024] Preferably, the need for regeneration and descaling of the device is determined by the following formula:

[0025]

[0026] In the formula, α represents the rate of decline in the softening and descaling effect of the device, and C i0 This indicates that the Ca in the influent of the device in the initial state is... 2+ Ion concentration, C o0 This indicates the Ca in the effluent from the device under initial conditions. 2+ Ion concentration, C it This indicates that after a period of time, Ca enters the water in the device. 2+ Ion concentration, C ot This indicates that after a period of time, the Ca in the water discharged from the device... 2+ When the ion concentration is α≥0.4, descaling and regeneration treatment is required.

[0027] The present invention has the following advantages and beneficial effects:

[0028] (1) The device of the present invention uses an isolation plate to separate the cathode reaction and the anode reaction, reducing the mixing of cathode products and anode products, improving the utilization rate of cathode products, and greatly improving the softening and descaling rate of the device.

[0029] (2) The three-section isolation plate design makes the device structure more compact and reasonable, and facilitates equipment maintenance.

[0030] (3) The device of the present invention is compact and ingenious in design and can be used as a unit structure to achieve large-scale application.

[0031] (4) The device of the present invention uses a combination of reversing the electrode and ultrasonic waves to achieve efficient and rapid regeneration of the cathode plate and the isolation membrane. This solves the problem of cathode dissolution during long-term reversing electrode regeneration and overcomes the problem that ultrasonic regeneration cannot quickly remove stubborn scale on the electrode surface. Attached Figure Description

[0032] Figure 1 This is a top view of the circulating cooling water electrochemical softening device of the present invention;

[0033] Figure 2 This is an isometric drawing of the circulating cooling water electrochemical softening device of the present invention;

[0034] Figure 3 This is another isometric view of the circulating cooling water electrochemical softening device of the present invention;

[0035] Figure 4 This is a schematic diagram of the perforated movable isolation plate structure of the circulating cooling water electrochemical softening device of the present invention;

[0036] Figure 5 This is a schematic diagram of the system process applicable to the circulating cooling water electrochemical softening device of the present invention;

[0037] Figure 6 This is a schematic diagram of a large-scale system for the circulating cooling water electrochemical softening device of the present invention;

[0038] Figure 7 This section explains the descaling effects of different descaling processes.

[0039] In the diagram: 1. Shell, 11. Cathode plate, 12. Anode plate, 2. Inlet pipe, 31. Cathode chamber outlet, 32. Anode chamber outlet, 41. Cathode chamber sludge discharge port, 411. Sludge discharge drive motor, 412. Spiral blade rod, 42. Anode chamber vent, 5. Perforated isolation plate, 51. Perforated fixed isolation plate, 52. Perforated movable isolation plate, 521. Inflatable sealing ring, 522. Sealing ring limiting groove, 523. Inflatable sealing ring inflation port, 524. L-shaped cylindrical shaft, 525. Round hole, 53. Isolation membrane, 6. Ultrasonic vibrating plate. Detailed Implementation

[0040] To better understand the present invention, the following embodiments are further illustrations of the present invention, but the content of the present invention is not limited to the following embodiments.

[0041] Example 1

[0042] like Figure 1-3 As shown, a circulating cooling water electrochemical softening device includes a shell 1, a cathode plate 11 and an anode plate 12 disposed within the shell 1, an inlet pipe 2 disposed on the side wall of the shell 1, a cathode chamber outlet 31, an anode chamber outlet 32, a cathode chamber sludge discharge port 41 and an anode chamber vent port 42, and also includes a sludge discharge drive motor 411, a spiral blade rod 412, a perforated isolation plate 5 and an ultrasonic vibration plate 6.

[0043] The cathode plate 11 and the anode plate 12 are separated by a perforated isolation plate 5 to form a cathode chamber and an anode chamber; the cathode plate 11 and the anode plate 12 are respectively connected to the negative and positive terminals of the DC power supply.

[0044] The lower side of the cathode chamber is connected to the water inlet pipe 2, the upper side is connected to the cathode chamber outlet 31, and the lower part is connected to the cathode chamber sludge discharge port 41.

[0045] A helical blade rod 412 is installed inside the pipe of the sludge discharge port 41 of the cathode chamber, and the helical blade rod 412 is connected to the sludge discharge drive motor 411.

[0046] The lower side of the anode chamber is connected to the water inlet pipe 2, the upper side is connected to the anode chamber outlet 32, and the lower part is connected to the anode chamber drain outlet 42.

[0047] The isolation membrane 53 is preferably a cation exchange membrane, which only allows cations to pass through the isolation membrane 53. A small amount of scale will also be generated on the cathode chamber side (through side) of the isolation membrane 53.

[0048] The ultrasonic vibrating plate 6 is placed in the cathode chamber, between the cathode plate 11 and the perforated isolation plate 5, to achieve simultaneous descaling and regeneration treatment of the cathode plate 11 and the isolation membrane 53; the ultrasonic vibrating plate 6 is electrically connected to the ultrasonic generator.

[0049] The cathode plate 11 can be made of stainless steel or carbon steel.

[0050] The anode plate 12 is an insoluble anode, such as a DSA electrode or an iridium-tantalum electrode.

[0051] The perforated isolation plate 5 adopts a three-section design, consisting of a fixed perforated isolation plate 51, an isolation membrane 53, and a movable perforated isolation plate 52; wherein the fixed perforated isolation plate 51 is integral with the shell 1; the movable perforated isolation plate 52 is connected to a fixed hollow cylindrical shaft set on the fixed perforated isolation plate 51 via an L-shaped cylindrical shaft 524; the isolation membrane 53 is sandwiched between the fixed perforated isolation plate 51 and the movable perforated isolation plate 52, and an inflatable sealing ring 521 is provided on the movable perforated isolation plate 52.

[0052] like Figure 4 As shown, the outer side of the perforated movable isolation plate 52 is provided with a sealing ring limiting groove 522, and an inflatable sealing ring 521 is provided in the sealing ring limiting groove 522. The inflatable sealing ring 521 is provided with an inflation port 523. The sealing ring is inflated and deflated through the inflation port 523 to achieve the purpose of sealing and unsealing. The perforated movable isolation plate 52 and the perforated fixed isolation plate 51 are arrayed with multiple through circular holes 525.

[0053] like Figure 5 The diagram shown is a schematic of the system flow applicable to the circulating cooling water electrochemical softening device of the present invention.

[0054] For large-scale circulating cooling water systems, the circulating cooling water electrochemical softening device of this embodiment is used as the basic unit structure, with multiple devices connected in parallel, such as... Figure 6 As shown, the design scale of the electrochemical softening system is related to the scale of the circulating cooling water system, and can be designed according to 5% to 10% of the water volume of the circulating cooling water system.

[0055] Example 2

[0056] A method for using a circulating cooling water electrochemical softening device, the specific steps of which are as follows:

[0057] When the circulating water electrochemical softening device of Example 1 is working normally, the circulating water enters the cathode chamber and the anode chamber from the inlet pipe 2 respectively.

[0058] In the cathode chamber, the following reactions mainly occur:

[0059] 2H2O+2e - →H₂↑+2OH - ;

[0060] O2 + 2H2O + 4e - →4OH - ;

[0061] HCO3 - +OH - →CO3 2- +H2O;

[0062] CO3 2- +Ca 2+ →CaCO3↓;

[0063] Through the above reaction process, scale-forming ions (Ca) in the water... 2+ Mg 2+ (etc.) and OH - HCO3 - CO3 2- A precipitation reaction occurs, thereby achieving the purpose of softening and descaling.

[0064] In the anode chamber, the following reactions mainly occur:

[0065] Cl - -2e - →Cl2↑

[0066] Cl₂ + H₂O → HClO + H₂ + +Cl -

[0067]

[0068] 2H2O-4e -+ →4H + +O2↑

[0069] The above reaction process produces highly oxidizing active chlorine, which has a bactericidal effect.

[0070] The treated circulating water overflows from the cathode chamber outlet 31 and the anode chamber outlet 32. The anode effluent can be directly returned to the system; the cathode chamber effluent still needs to be filtered, such as... Figure 5 As shown, this removes suspended scale and prevents it from redissolving when returned to the system.

[0071] Furthermore, after the equipment has been running normally for a period of time, scale will accumulate on the surfaces of the cathode plate 11 and the isolation membrane 53. At this point, a descaling and regeneration process is required. During implementation, the following formula can be used to determine whether the device needs to undergo regeneration and descaling:

[0072]

[0073] In the formula, α represents the rate of decline in the softening and descaling effect of the device, and C i0 This indicates that the Ca in the influent of the device in the initial state is... 2+ Ion concentration, C o0 This indicates the Ca in the effluent from the device under initial conditions. 2+ Ion concentration, C it This indicates that after a period of time, Ca enters the water in the device. 2+ Ion concentration, C ot This indicates that after a period of time, the Ca in the water discharged from the device... 2+ Ion concentration.

[0074] When α ≥ 0.4, it is recommended to start the descaling and regeneration program. The specific steps are as follows:

[0075] S1: Turn off the DC power supply, switch the connection between the DC power supply and the plates, connect the cathode plate 11 to the positive terminal of the DC power supply; connect the anode plate 12 to the negative terminal of the DC power supply.

[0076] S2: Turn on the direct power supply and simultaneously turn on the ultrasonic generator;

[0077] S3: After running for 1-5 minutes, turn off the ultrasonic generator and disconnect the DC power supply.

[0078] S4: Restore the connection between the DC power supply and the plates. Connect the cathode plate 11 to the negative terminal of the DC power supply and the anode plate 12 to the positive terminal of the DC power supply. Then, normal operation will begin.

[0079] Furthermore, the removed scale will accumulate at the bottom of the cathode chamber of the device. The sludge discharge drive motor 411 is turned on to drive the spiral blade rod 412 to discharge sludge through the sludge discharge port 41 of the cathode chamber.

[0080] Example 3:

[0081] The circulating cooling water electrochemical softening device of Example 1 was used to treat the circulating cooling water of a power plant. The parameters of the circulating cooling water electrochemical softening device were: electrode spacing 20 cm, and effective cathode electrode area 6.75 m². 2 Current density is 80A / m 2 Operating voltage: <36V; Flow rate: 100m³ 3 / h; the calcium ion concentration in the circulating cooling water is 4.42 mmol / L, and the magnesium ion concentration is 2.09 mmol / L. The softening and sedimentation rate of this invention can reach 167.59 g / m³. 2 / h, calculated as CaCO3.

[0082] Figure 7 The diagram shows the descaling effect of different descaling processes. By comparing different cathode descaling processes, it can be found that the reverse electrode combined with ultrasonic waves can achieve a very good descaling effect.

[0083] The above description is merely a preferred embodiment of the present invention, and should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A circulating cooling water electrochemical softening device, characterized in that: Includes a housing (1), a cathode plate (11) and an anode plate (12) disposed within the housing (1), wherein the cathode plate (11) and the anode plate (12) are separated by a perforated partition plate (5) to form a cathode chamber and an anode chamber; The perforated isolation plate (5) consists of a perforated fixed isolation plate (51), a perforated movable isolation plate (52), and an isolation membrane (53) sandwiched between the perforated fixed isolation plate (51) and the perforated movable isolation plate (52). The perforated fixed isolation plate (51) is fixedly connected to the shell (1); the perforated movable isolation plate (52) is rotatably connected to the perforated fixed isolation plate (51), and an inflatable sealing ring (521) is provided on the perforated movable isolation plate (52). An ultrasonic transducer (6) is provided in the cathode chamber, and the ultrasonic transducer (6) is electrically connected to the ultrasonic generator. When the cathode plate and the separator are covered with scale, a combination of reverse polarity and ultrasonic waves is used for descaling and regeneration.

2. The circulating cooling water electrochemical softening device according to claim 1, characterized in that: The housing (1) is also provided with a water inlet pipe (2), a cathode chamber outlet (31) and an anode chamber outlet (32). The lower side of the cathode chamber and the lower side of the anode chamber are connected to the water inlet pipe (2). The upper side of the cathode chamber is connected to the cathode chamber outlet (31), and the upper side of the anode chamber is connected to the anode chamber outlet (32).

3. The circulating cooling water electrochemical softening device according to claim 1, characterized in that: The shell (1) is also provided with a cathode chamber sludge discharge port (41) that communicates with the cathode chamber, and a spiral blade rod (412) is provided at the cathode chamber sludge discharge port (41).

4. The circulating cooling water electrochemical softening device according to claim 1, characterized in that: The separating membrane (53) is a cation exchange membrane.

5. A method of using the circulating cooling water electrochemical softening device according to any one of claims 1-4, characterized in that, Includes the following steps: The cathode plate (11) and anode plate (12) are connected to the negative and positive terminals of the DC power supply, respectively. The device is started and the circulating water enters the cathode chamber and anode chamber, respectively. In the cathode chamber, the scale-forming ions in the water undergo a precipitation reaction, and in the anode chamber, an oxidation reaction is carried out to produce a highly oxidizing active chlorine component, which plays a bactericidal role. The treated water is discharged from the anode chamber and cathode chamber, respectively, to obtain the treated circulating water. After the device has been running for a certain period of time, scale will be covered on the surface of the cathode plate and the isolation membrane. Descaling and regeneration are carried out by using a combination of reverse polarity and ultrasonic waves.

6. The method of using the circulating cooling water electrochemical softening device according to claim 5, characterized in that, The descaling and regeneration process includes the following steps: S1: Turn off the DC power supply, connect the cathode plate to the positive terminal of the DC power supply, and connect the anode plate to the negative terminal of the DC power supply. S2: Start the DC power supply and turn on the ultrasonic generator at the same time; S3: After running for 1-5 minutes, turn off the ultrasonic generator and disconnect the DC power supply to complete the descaling and regeneration process.

7. The method of using the circulating cooling water electrochemical softening device according to claim 6, characterized in that: The ultrasonic frequency range is 20kHz to 28kHz.

8. The method of using the circulating cooling water electrochemical softening device according to claim 5, characterized in that: The following formula can be used to determine whether the device requires regeneration and descaling: In the formula, C represents the rate of decline in the softening and descaling effect of the device. i0 This indicates that the Ca in the influent of the device in the initial state is... 2+ Ion concentration, C o0 This indicates the Ca in the effluent of the device under initial conditions. 2+ Ion concentration, C it This indicates that after a period of time, Ca enters the water in the device. 2+ Ion concentration, C ot This indicates that after a period of time, the Ca in the water discharged from the device... 2+ Ion concentration, when When the value is ≥0.4, descaling and regeneration treatment is required.

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