Electrolytic seawater descaling system and descaling method

Abstract

The invention discloses an electrolytic seawater descaling system and descaling method, and belongs to the technical field of descaling. The descaling system comprises an electrolytic bath; seawater is filled in the electrolytic bath, an anode and a cathode are inserted in the seawater, and the anode and the cathode are titanium metal devices attached with scale layers; the anode and the cathode are electrically connected with the anode and the cathode of a power supply respectively. When the descaling is carried out, the anode and the cathode are electrified by utilizing a power supply. According to the descaling method, the scale layer deposited on the surface of the electrode can be actively removed through the mechanical stripping effect of the electrolytic bubbles, and the self-cleaning descaling function in the true sense is achieved. The characteristic obviously improves the continuous operation capability and maintenance convenience of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of descaling, and in particular relates to a descaling system and a descaling method for electrolyzing seawater. Background Art

[0002] Titanium alloys are widely used in aerospace, shipbuilding, energy equipment and other fields due to their excellent specific strength, corrosion resistance and heat resistance. With the development of material technology, titanium alloy pipes have shown significant advantages in seawater heat exchange systems in ships, nuclear power plants and thermal power plants. However, in fluid heat exchange systems, pipe scaling has always been one of the main technical bottlenecks restricting system performance. Especially in seawater medium environments, due to the high salinity characteristics of seawater and its complex physical and chemical properties, the inner wall of the pipe is affected by multiple factors such as physical deposition and chemical crystallization during long-term service, forming scale accumulation. Pipeline scaling can cause many serious problems, which not only reduces heat transfer efficiency and increases flow resistance, but also causes severe under-scale corrosion, ultimately leading to a decline in system performance and a surge in maintenance costs.

[0003] Electrochemical descaling technology has attracted much attention due to its environmentally friendly characteristics. The core mechanism of this technology is to soften water through electrochemical induction crystallization, and to induce Ca in the circulating water to 2+ Mg 2+ Scale-forming ions such as calcium carbonate are selectively deposited on the cathode surface, thereby effectively reducing the hardness of the water and inhibiting the scaling tendency of the inner wall of the pipe. However, this technology has obvious application limitations: first, in open fluid systems, due to the instability of the electrolysis environment, its descaling efficiency will be significantly reduced; second, in seawater heat exchange systems, high concentrations of Ca 2+ Mg 2+ This will cause rapid scaling on the cathode surface, which not only affects the continuous operation capability of the device, but also requires frequent manual cleaning of the cathode scale layer. At the same time, the electrode materials of this technology usually need to be coated with precious metal oxides to cope with the high corrosiveness of the seawater environment. More importantly, this technology can only prevent the formation of new scale by softening the water quality, and cannot effectively strip off the deposited scale layer on the inner wall of the existing pipeline. As the service time of the pipeline increases, it is still necessary to rely on auxiliary means such as high-pressure water jets or manual removal to remove scale, which not only increases maintenance costs, but also significantly reduces the overall practicality and economy of the descaling system. These technical bottlenecks limit the promotion and application of electrochemical descaling technology in a wider range of fields. Summary of the Invention

[0004] In view of the above-mentioned prior art, the present invention provides a system and method for electrolyzing seawater to remove scale, so as to solve the technical problems of low efficiency and high cost of the existing descaling process.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide an electrolytic seawater descaling system, including an electrolytic cell; the electrolytic cell is filled with seawater, and an anode and a cathode are inserted into the seawater, and the anode and the cathode are both titanium metal devices with a scale layer attached; the anode and the cathode are electrically connected to the positive and negative poles of a power supply, respectively.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the anode and cathode are immersed in seawater.

[0008] Furthermore, the distance between the anode and cathode is 2~5cm.

[0009] Furthermore, the material of the titanium metal device is TC4 titanium alloy.

[0010] Furthermore, the power supply is a DC regulated power supply.

[0011] The electrolytic seawater descaling system of the present invention uses seawater as the electrolytic medium and removes scale by generating chlorine (Cl2) and hydrogen (H2) during the electrolysis of seawater. During the electrolysis of seawater, an oxidation reaction occurs at the anode, and the chloride ions in the seawater lose electrons on the anode surface to generate chlorine. The main reaction formula is:

[0012] 2Cl - -2e - →Cl2↑

[0013] A reduction reaction occurs at the cathode to produce hydrogen. The main reaction formula is:

[0014] 2H2O+2e⁻→H2↑+2OH⁻

[0015] As the electrolysis reaction continues, the bubbles generated on the electrode surface undergo a complete nucleation-growth-precipitation process: first, nucleation occurs at the interface of the metal substrate (titanium metal device), followed by continuous growth and aggregation under the action of the electric field. Due to the close coverage of the substrate by the scale layer, these bubbles gradually transfer from the metal-solution interface to the scale-metal interface, where they continue to accumulate. As the number of bubbles increases, local air cavities form at the interface, effectively reducing the adsorption force between the deposited scale layer and the substrate surface. When the air cavity pressure reaches a critical value, the bubble group acts synergistically, causing the covering scale layer to locally bulge and eventually peel off from the substrate surface as the air cavity ruptures. This spontaneous cleaning mechanism based on the dynamic behavior of bubbles achieves efficient removal of the scale layer through the interaction of the gas-liquid-solid three-phase interface.

[0016] The present invention also discloses a method for descaling by electrolyzing seawater, which is characterized by comprising the following steps:

[0017] S1: The titanium metal device with a scale layer is used as the anode and cathode, and connected to the positive and negative electrodes of the power supply respectively to construct the above-mentioned electrolysis seawater descaling system;

[0018] S2: Use a power supply to apply voltage to the anode and cathode until the scale layer attached to the surface of the titanium metal device falls off.

[0019] Furthermore, the voltage applied in S2 is 5~7.5V.

[0020] The beneficial effects of the present invention are:

[0021] 1. The anode and cathode of the electrolytic seawater descaling system of the present invention are both titanium metal devices made of the same material. Utilizing the excellent corrosion resistance of titanium in seawater environment, there is no need to plate a precious metal oxide coating on its surface. The system is simplified due to the unified material.

[0022] 2. The use of the same material for the anode and cathode of the electrolytic seawater descaling system of the present invention can eliminate the risk of galvanic corrosion and avoid the problem of accelerated corrosion caused by the potential difference between electrodes of different materials; titanium metal devices show unique tolerance to strong oxidizing media such as active chlorine generated during the electrolysis process, thereby ensuring that the system can maintain long-term stable operation under harsh working conditions of high salinity and strong oxidizing properties.

[0023] 3. Compared to the limitations of traditional electrochemical descaling technologies, which only inhibit scaling, the descaling method of this invention actively removes deposited scale from the electrode surface through the mechanical exfoliation effect of electrolytic bubbles, achieving true self-cleaning and descaling. This feature significantly improves the system's continuous operation and ease of maintenance.

[0024] 4. Traditional electrochemical descaling technology is limited to softening water and can only remove scale-forming ions such as calcium and magnesium. It is ineffective against complex seawater scale deposits such as those containing silt, sand, and inorganic salt deposits. This innovative method achieves a breakthrough, fully cleaning complex seawater scale layers and addressing the shortcomings of traditional technologies. Furthermore, no additional descaling agents are required during the descaling process, resulting in lower descaling costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of the electrolytic seawater descaling system;

[0026] Figure 2 This is the descaling principle diagram of the electrolytic seawater descaling system;

[0027] Figure 3 This is the surface state diagram of the titanium metal plate after hanging sample treatment;

[0028] Figure 4 A diagram showing the states of the anode and cathode during the descaling process of electrolyzing seawater;

[0029] Figure 5This is a comparison chart of the anode and cathode before and after descaling;

[0030] Figure 6 The following are scanning electron microscope images of the anode and cathode before and after descaling;

[0031] Among them, 1. power supply; 2. anode; 3. cathode; 4. electrolytic cell; 5. seawater; 6. scale layer; 7. air cavity. DETAILED DESCRIPTION

[0032] The structural diagram of the electrolytic seawater descaling system of the present invention is as follows: Figure 1 As shown, it includes an electrolytic cell 4; the electrolytic cell 4 is filled with seawater 5, and the anode 2 and the cathode 3 are inserted into the seawater 5. In order to produce a better descaling effect, the anode 2 and the cathode 3 are all immersed in the seawater 5, and the distance between the anode 2 and the cathode 3 is controlled to be 2~5cm; the anode 2 and the cathode 3 are both titanium metal devices with a scale layer 6 attached, such as titanium metal pipes, titanium metal plates, etc., and the anode 2 and the cathode 3 are made of the same material, which can be pure titanium or a titanium alloy, such as TC4 titanium alloy, etc.; the anode 2 and the cathode 3 are electrically connected to the positive and negative electrodes of the power supply 1, respectively. In order to more stably electrolyze the seawater to remove the scale layer attached to the electrodes, the power supply 1 is preferably a DC regulated power supply.

[0033] The principle of using the electrolytic seawater descaling system of the present invention to perform descaling is as follows: Figure 2 As shown, specifically, during the electrolysis of seawater, an oxidation reaction occurs at the anode 2, causing chloride ions in the seawater 5 to lose electrons on the anode 2 surface to produce chlorine gas, while a reduction reaction occurs at the cathode 3 to produce hydrogen gas. As the electrolysis reaction continues, bubbles generated on the electrode surface undergo a complete nucleation-growth-precipitation process: first, nucleation occurs at the electrode-substrate interface, followed by continuous growth and aggregation under the action of the electric field. Due to the tight coverage of the scale layer 6 on the electrode substrate, these bubbles gradually migrate from the metal-solution interface to the scale-metal interface, where they continue to accumulate. As the number of bubbles increases, local air cavities 7 form at the interface, effectively reducing the adsorption force between the scale layer 6 and the substrate surface. When the pressure in the air cavity 7 reaches a critical value, the bubble clusters work together to cause the covering scale layer 6 to locally bulge, which ultimately peels off from the substrate surface as the air cavity 7 ruptures. This spontaneous cleaning mechanism, based on the dynamic behavior of bubbles, achieves efficient scale removal through the interaction of the gas-liquid-solid three-phase interface.

[0034] The specific embodiments of the present invention are described in detail below with reference to the examples. The titanium metal plate used in the examples is a TC4 titanium alloy plate, and has been subjected to a sample hanging treatment, wherein the sample hanging treatment method is: placing the titanium metal plate in a seawater pipeline for 60 days. Figure 3 As shown in the figure, a uniformly distributed dirt layer accumulates on the surface of the sample, which fully simulates the scaling characteristics of the inner wall of the seawater pipeline under actual working conditions.

[0035] Example 1

[0036] A method for descaling by electrolyzing seawater, comprising the following steps:

[0037] S1: The titanium metal plate with the scale layer 6 is used as the anode 2 and cathode 3, and connected to the positive and negative electrodes of the DC regulated power supply 1 respectively, to construct the following Figure 1 The electrolytic seawater descaling system shown;

[0038] S2: Use power supply 1 to apply voltage to anode 2 and cathode 3. The applied voltage is 5V and the power-on time is 1 hour, so that the scale layer 6 attached to the surface of the titanium metal device falls off.

[0039] Example 2

[0040] A method for descaling by electrolyzing seawater, comprising the following steps:

[0041] S1: The titanium metal plate with the scale layer 6 is used as the anode 2 and cathode 3, and connected to the positive and negative electrodes of the DC regulated power supply 1 respectively, to construct the following Figure 1 The electrolytic seawater descaling system shown;

[0042] S2: Use power supply 1 to apply voltage to anode 2 and cathode 3. The applied voltage is 7.5V and the power-on time is 2 hours, so that the scale layer 6 attached to the surface of the titanium metal device falls off.

[0043] Result Analysis

[0044] In order to systematically evaluate the descaling effect, the present invention adopts a multi-scale characterization method: first, a digital camera is used to record the macroscopic morphological changes of the sample surface before and after electrolysis to intuitively demonstrate the cleaning effect; then a scanning electron microscope is used to observe the microscopic morphology of the treated sample surface, focusing on analyzing whether defects such as corrosion pits are generated on the surface, so as to comprehensively evaluate the impact of electrolytic treatment on the material surface.

[0045] During the electrolytic descaling process, the states of the anode 2 and cathode 3 are as follows: Figure 4 As shown. Figure 4 It can be seen from the figure that during the electrolytic descaling process, a large number of bubbles are generated at both the anode 2 and the cathode 3. The formation and rupture of these bubbles can promote the peeling of the scale layer 6 from the electrode surface, thereby achieving the purpose of descaling.

[0046] The comparison of the electrode before and after descaling in Example 1 is as follows: Figure 5 As shown in the figure, it can be seen that most of the dirt on the surface of the electrode sample has been removed after cleaning, and the remaining dirt is loose, indicating that the bubbles effectively reduce the adsorption force of the dirt on the sample surface.

[0047] The surface micromorphology of the electrode samples after electrolytic cleaning in Example 1 and Example 2 was observed by scanning electron microscope. Figure 6 As shown in the figure, after electrolytic treatment, the surfaces of the electrode samples remained intact, with no pitting or other obvious corrosion defects observed. This demonstrates that the present invention effectively removes the fouling layer on the titanium alloy surface without damaging the titanium alloy electrode substrate, demonstrating excellent surface protection.

[0048] Although the specific embodiments of the present invention have been described in detail in conjunction with the embodiments, this should not be construed as limiting the scope of protection of this patent. Within the scope described by the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An electrolytic seawater descaling system, characterized by: The invention comprises an electrolytic cell (4); the electrolytic cell (4) contains seawater (5); an anode (2) and a cathode (3) are inserted into the seawater (5); the anode (2) and the cathode (3) are both titanium metal devices with a scale layer (6) attached thereto; the anode (2) and the cathode (3) are electrically connected to the positive electrode and the negative electrode of a power supply (1), respectively.

2. The electrolytic seawater descaling system according to claim 1, characterized in that: The anode (2) and cathode (3) are immersed in seawater (5).

3. The electrolytic seawater descaling system according to claim 1, characterized in that: The distance between the anode (2) and the cathode (3) is 2 to 5 cm.

4. The electrolytic seawater descaling system according to claim 1, characterized in that: The material of the titanium metal device is TC4 titanium alloy.

5. The electrolytic seawater descaling system according to claim 1, characterized in that: The power supply (1) is a DC regulated power supply.

6. A method for descaling by electrolyzing seawater, characterized in that: The following steps are involved: S1: A titanium metal device with a scale layer (6) attached thereto is used as an anode (2) and a cathode (3), and is connected to the positive electrode and the negative electrode of a power source (1) respectively, to construct the electrolytic seawater descaling system according to any one of claims 1 to 5; S2: Using a power supply (1), a voltage is applied to the anode (2) and the cathode (3) until the scale layer (6) attached to the surface of the titanium metal device falls off.

7. The method for descaling by electrolyzing seawater according to claim 6, wherein: The voltage applied to S2 is 5~7.5V.

Images