Electrolytic seawater descaling system and descaling method

Abstract

The application discloses an electrolytic seawater descaling system and a descaling method, and belongs to the technical field of descaling. The descaling system comprises an electrolytic tank; seawater is arranged in the electrolytic tank; an anode and a cathode are arranged in the seawater; the anode and the cathode are both titanium metal devices with scale layers attached; and the anode and the cathode are electrically connected with a positive electrode and a negative electrode of a power supply respectively. When descaling is performed, the anode and the cathode are powered by the power supply. The descaling method in the application can actively remove the scale layers deposited on the surface of the electrode through the mechanical stripping effect of electrolytic bubbles, realizes the self-cleaning descaling function in a true sense, and significantly improves the continuous operation capability and maintenance convenience of the system.

Description

Technical Field

[0001] This invention belongs to the field of descaling technology, specifically relating to an electrolytic seawater descaling system and method. Background Technology

[0002] Titanium alloys are widely used in aerospace, shipbuilding, and energy equipment due to their excellent specific strength, corrosion resistance, and heat resistance. With the development of materials 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 remains one of the main technical bottlenecks restricting system performance. Especially in seawater environments, due to the high salinity and complex physicochemical properties of seawater, the inner walls of pipes are subjected to multiple influences, including physical deposition and chemical crystallization, leading to scale buildup during long-term service. Pipe scaling causes many serious problems, not only reducing heat transfer efficiency and increasing flow resistance, but also triggering severe under-deposit corrosion, ultimately resulting in decreased system performance and soaring 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 electrochemically induced crystallization. This is achieved through the synergistic effect of electrolysis and an electric field, inducing the removal of calcium deposits in the circulating water. 2+ Mg 2+ Scale-forming ions selectively deposit on the cathode surface, effectively reducing water hardness and inhibiting scaling on pipe inner walls. However, this technology has significant limitations: firstly, in open fluid systems, its descaling efficiency decreases significantly due to the instability of the electrolytic environment; secondly, in seawater heat exchange systems, high concentrations of Ca2+... 2+ Mg 2+ This leads to rapid scaling on the cathode surface, affecting the continuous operation of the device and requiring frequent manual cleaning of the scale layer. Furthermore, the electrode materials used in this technology typically require a coating of precious metal oxides to withstand the high corrosiveness of seawater. More critically, this technology can only prevent new scale formation through water softening; it cannot effectively remove existing scale deposits from the inner walls of pipelines. As pipelines age, high-pressure water jetting or manual cleaning remains necessary to remove scale, increasing maintenance costs and significantly reducing the overall practicality and cost-effectiveness of the descaling system. These technical bottlenecks limit the wider application of electrochemical descaling technology. Summary of the Invention

[0004] In view of the above-mentioned prior art, the present invention provides an electrolytic seawater descaling system and descaling method to solve the technical problems of low efficiency and high cost of existing descaling processes.

[0005] To achieve the above objectives, 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 in the seawater, both of which are titanium metal devices with scale deposits; the anode and the cathode are electrically connected to the positive and negative terminals of a power source, respectively.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

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

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

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

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

[0011] The seawater electrolysis descaling system of this invention uses seawater as the electrolysis medium, achieving descaling through the chlorine (Cl2) and hydrogen (H2) gas generated during the electrolysis process. During seawater electrolysis, an oxidation reaction occurs at the anode, where chloride ions in the seawater lose electrons at the anode surface to generate chlorine gas. The main reaction formula is as follows:

[0012] 2Cl - -2e - →Cl2↑

[0013] A reduction reaction occurs at the cathode to produce hydrogen gas. 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-deposition process: First, nucleation occurs at the metal substrate (titanium device) interface, followed by continuous growth and aggregation under the influence of the electric field. Due to the tight coverage of the substrate by the fouling layer, these bubbles gradually migrate from the metal-solution interface to the fouling-metal interface, where they accumulate. As the number of bubbles increases, localized gas cavities form at the interface, effectively reducing the adhesion between the deposited fouling layer and the substrate surface. When the pressure in the gas cavity reaches a critical value, the bubble swarm works synergistically, causing the covered fouling layer to bulge locally and eventually peel off from the substrate surface as the gas cavity ruptures. This spontaneous cleaning mechanism based on the dynamic behavior of bubbles achieves highly efficient removal of the fouling layer through the interaction of the gas-liquid-solid three-phase interface.

[0016] This invention also discloses a method for descaling seawater by electrolysis, characterized by comprising the following steps:

[0017] S1: The above-mentioned electrolytic seawater descaling system is constructed by using a titanium metal device with scale deposits as the anode and cathode, and connecting them to the positive and negative terminals of the power supply, respectively.

[0018] S2: Apply voltage to the anode and cathode using a power source until the scale layer attached to the surface of the titanium metal device is removed.

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

[0020] The beneficial effects of this invention are:

[0021] 1. The anode and cathode of the electrolytic seawater descaling system in this invention are both made of titanium metal devices of the same material. Taking advantage of the excellent corrosion resistance of titanium in the seawater environment, there is no need to plate it with a precious metal oxide coating. The system is simplified due to the uniformity of materials.

[0022] 2. The use of the same material for the anode and cathode of the electrolytic seawater descaling system in this invention can eliminate the risk of galvanic corrosion and avoid accelerated corrosion caused by the potential difference between electrodes of different materials; the titanium metal device exhibits 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 conditions of high salinity and strong oxidation.

[0023] 3. Compared to the limitations of traditional electrochemical descaling technologies that can only inhibit scale formation, the descaling method in this invention actively removes the scale layer already deposited on the electrode surface through the mechanical stripping action of electrolytic bubbles, achieving a true self-cleaning descaling function. This feature significantly improves the system's continuous operation capability and ease of maintenance.

[0024] 4. Traditional electrochemical descaling technologies are limited to softening water and can only remove scale-forming ions such as calcium and magnesium to a limited extent. They are ineffective against complex seawater scale containing silt, sand, and inorganic salt deposits. This invention achieves an innovative breakthrough, capable of comprehensively cleaning complex seawater scale layers and overcoming the shortcomings of traditional technologies. Furthermore, no additional descaling reagents are required during the descaling process, resulting in lower descaling costs. Attached Figure Description

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

[0026] Figure 2 This is a schematic diagram of the descaling principle of an electrolytic seawater descaling system.

[0027] Figure 3 The image shows the surface condition of the titanium metal plate after sample treatment.

[0028] Figure 4 This is a diagram showing the state of the anode and cathode during the electrolytic seawater descaling process;

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

[0030] Figure 6 Scanning electron microscope (SEM) images of the anode and cathode before and after descaling;

[0031] Among them, 1. Power source; 2. Anode; 3. Cathode; 4. Electrolytic cell; 5. Seawater; 6. Scale layer; 7. Gas chamber. Detailed Implementation

[0032] A schematic diagram of the electrolytic seawater descaling system of this invention is shown below. Figure 1 As shown, the device includes an electrolytic cell 4; the electrolytic cell 4 is filled with seawater 5, and an anode 2 and a cathode 3 are inserted in the seawater 5. In order to produce a better descaling effect, both the anode 2 and the cathode 3 are completely submerged in the seawater 5, and the distance between the anode 2 and the cathode 3 is controlled to be 2~5cm; both the anode 2 and the cathode 3 are titanium metal devices with 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 titanium alloy, such as TC4 titanium alloy, etc.; the anode 2 and the cathode 3 are electrically connected to the positive and negative terminals 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 descaling using the electrolytic seawater descaling system of this invention is as follows: Figure 2 As shown, specifically, during the electrolysis of seawater, oxidation occurs at anode 2, where chloride ions in seawater 5 lose electrons to generate chlorine gas on the surface of anode 2, while reduction occurs at cathode 3 to produce hydrogen gas. As the electrolysis continues, the 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 influence of an electric field. Due to the tight coverage of the electrode substrate by the scale layer 6, these bubbles gradually transfer from the metal-solution interface to the dirt-metal interface, where they continuously accumulate. As the number of bubbles increases, local gas cavities 7 are formed at the interface, effectively reducing the adsorption force between the scale layer 6 and the substrate surface. When the pressure in the gas cavity 7 reaches a critical value, the bubble swarm works synergistically, causing the covered scale layer 6 to bulge locally and eventually peel off from the substrate surface as the gas cavity 7 ruptures. This spontaneous cleaning mechanism based on the dynamic behavior of bubbles achieves highly efficient removal of the scale layer through the interaction of the gas-liquid-solid three-phase interface.

[0034] The specific embodiments of the present invention will be described in detail below with reference to examples. The titanium metal plate used in the examples is a TC4 titanium alloy plate, and it has undergone a sample hanging treatment. The sample hanging treatment method is as follows: the titanium metal plate is placed in a seawater pipeline for 60 days. The TC4 titanium alloy plate after the sample hanging treatment is shown below. Figure 3 As shown, a uniformly distributed layer of dirt accumulated on the sample surface, completely simulating the scaling characteristics of the inner wall of a seawater pipeline under actual working conditions.

[0035] Example 1

[0036] A method for descaling seawater by electrolysis includes the following steps:

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

[0038] S2: Apply a voltage of 5V to the anode 2 and cathode 3 using power supply 1 for 1 hour to remove the scale layer 6 adhering to the surface of the titanium metal device.

[0039] Example 2

[0040] A method for descaling seawater by electrolysis includes the following steps:

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

[0042] S2: Apply a voltage of 7.5V to the anode 2 and cathode 3 using power supply 1 for 2 hours to remove the scale layer 6 adhering to the surface of the titanium metal device.

[0043] Results Analysis

[0044] To systematically evaluate the descaling effect, this invention employs 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, visually demonstrating 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, in order to comprehensively evaluate the impact of electrolysis on the material surface.

[0045] During the electrostatic descaling process, the states of anode 2 and cathode 3 are as follows: Figure 4 As shown. From Figure 4 As can be seen, during the electrolytic descaling process, both the anode 2 and the cathode 3 generate a large number of bubbles. 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] Comparison of electrode electrostatic descaling before and after in Example 1 Figure 5 As shown in the figure, most of the dirt on the surface of the electrode sample has been removed after cleaning, and the remaining dirt is in a loose state, indicating that the air bubbles effectively reduced the adsorption force of the dirt on the sample surface.

[0047] The microstructure of the electrode samples after electrolytic cleaning in Examples 1 and 2 was observed using scanning electron microscopy. The results are as follows: Figure 6 As shown in the figure, after electrolytic treatment, the surface of the electrode samples remained intact, with no pitting or other obvious corrosion defects observed. This indicates that the present invention effectively removes the dirt layer on the surface of titanium alloy without damaging the titanium alloy electrode substrate material, thus exhibiting excellent surface protection performance.

[0048] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A method for descaling seawater by electrolysis, characterized in that, Includes the following steps: S1: A titanium metal device with scale layer (6) attached is used as the anode (2) and cathode (3), and is connected to the positive and negative terminals of the power supply (1) respectively to construct an electrolytic seawater descaling system; the electrolytic seawater descaling system includes an electrolytic cell (4); the electrolytic cell (4) is filled with seawater (5), and the anode (2) and cathode (3) are inserted in the seawater (5). The anode (2) and cathode (3) are both titanium metal devices with scale layer (6) attached; the anode (2) and cathode (3) are electrically connected to the positive and negative terminals of the power supply (1) respectively; S2: Apply voltage to the anode (2) and cathode (3) using power supply (1) until the scale layer (6) attached to the surface of the titanium metal device falls off. The applied voltage is 5~7.5V.

2. The method for descaling seawater by electrolysis according to claim 1, characterized in that: The anode (2) and cathode (3) are immersed in seawater (5).

3. The method for descaling seawater by electrolysis according to claim 1, characterized in that: The distance between the anode (2) and the cathode (3) is 2~5cm.

4. The method for descaling seawater by electrolysis according to claim 1, characterized in that: The titanium metal device is made of TC4 titanium alloy.

5. The method for descaling seawater by electrolysis according to claim 1, characterized in that: The power supply (1) is a DC regulated power supply.

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