Efficient electrochemical descaling device and method for clean circulating water system

Abstract

The invention relates to an efficient electrochemical descaling device and method for a circulating water cleaning system, the device comprises a cathode and an anode, the cathode is made of a high-entropy alloy material, and the anode is made of nanoscale zero-valent iron coated with SiO2; the cathodes and the anodes are alternately and concentrically arranged, and the cathode plates and the anode plates are the same in size. The invention provides the novel electrode with strong corrosion resistance, the scale inhibiting and removing effects are better by optimizing the structure of the electrochemical reactor, the descaling efficiency of the electrochemical method can be obviously improved, and the novel electrode has the characteristics of safety, environmental protection, high efficiency and cost reduction.

Description

Technical Field

[0001] The present invention belongs to the technical field of scale and corrosion inhibition in circulating water systems, and particularly relates to a device and method for efficient electrochemical scale removal in a clean circulating water system. Background Art

[0002] The clean circulating water system is essential in metallurgical enterprises. However, during long-term cyclic operation, the equipment and pipelines in the circulating water system are severely fouled and blocked. The main reason is that metal ions such as Ca and Mg react with alkaline substances during the circulation process and precipitate and separate out. Especially in summer, the overall temperature rises, including the temperature of the cooling water and the temperature of the medium to be cooled, which further exacerbates the precipitation of metal ions such as Ca and Mg, increases the generation of scale, and ultimately leads to serious scale formation.

[0003] Conventional treatment methods for fouled equipment pipelines include high-pressure water cleaning, acid cleaning, and copper brush cleaning, with copper brush cleaning being more common. Cleaning will reduce the service life of the equipment, increase the wastewater discharge, and pollute the environment. Frequent cleaning requires regular shutdowns, affecting the continuous operation of the equipment and bringing great uncertainty to the reliability of the equipment, posing potential safety hazards for the long-term operation of the equipment. Currently, the commonly used scale and corrosion inhibition methods are to add a large amount of corrosion inhibitors and scale inhibitors to the circulating water system to slow down equipment fouling and corrosion. The expenditure on chemical agents is huge. At the same time, the large addition of agents also causes secondary pollution to the circulating water, resulting in the adverse consequence of increased salt content in the water.

[0004] The electrochemical circulating water water quality stabilization treatment technology has good corrosion inhibition, scale inhibition, and bactericidal and algaecidal effects. The circulating water system applying this technology does not need to add any chemical agents, and the amount of forced sewage discharge is small. It can not only save chemical agent costs and make-up water costs, but also has good energy conservation, emission reduction, and environmental protection effects. Therefore, it is urgent to study a highly efficient electrochemical scale removal technology to meet the scale removal needs of the clean circulating water system.

[0005] The patent document with the publication number of CN 116282749 A discloses "a carbon dioxide aeration electrochemical scale removal and filtration coupling system and its scale removal method". The system includes a reaction chamber main body, anode and cathode plates, an aeration device, and a filtration device; the reaction chamber is separated into an anode chamber and a cathode chamber by an ion exchange membrane; the cathode chamber is aerated through the aeration device to increase alkalinity, and at the same time, it also flushes the cathode plate, delaying the deposition of scale-forming substances on the surface of the electrode plates; and the flow mode of a small part of the water body into the anode reduces the alkalinity and pH. The filtration device plays a good role in intercepting the crystal particles and suspended substances flowing out of the cathode chamber, preventing scale-forming substances from flowing into the pipeline and forming deposits. However, this method only modifies the electrochemical scale removal device and does not cooperate with other technical means, and the effect may not be obvious.

[0006] The patent document with the publication number CN 115745090 A discloses "a circulating water electrochemical continuous pole-reversing scale removal system", which includes a working circuit, a pole-reversing circuit, a number of electrochemical scale removal devices, a number of device electronic control working switches, a number of device electronic control pole-reversing switches and a number of aeration branches; a sludge discharge port and a water inlet are provided at the bottom of the electrochemical scale removal device; one electrochemical scale removal device corresponds to one aeration branch, one device electronic control pole-reversing switch and one device electronic control working switch; the outlet of the air pump is connected to the inlet of each aeration branch, and the outlet of each aeration branch is connected to the aeration head on the side of the bottom of the corresponding electrochemical scale removal device. The working circuit is connected to one end of each device electronic control working switch, and the other end of each device electronic control working switch is connected to the power supply interface of the corresponding electrochemical scale removal device. The pole-reversing circuit is connected to one end of each device electronic control pole-reversing switch, and the other end of each device electronic control pole-reversing switch is connected to the power supply interface of the corresponding electrochemical scale removal device. This system can achieve continuous electrochemical scale removal of circulating water. However, the operation process of this patent is cumbersome, the structure is complex, and the cost is relatively high.

[0007] The patent document with the publication number CN 217498765 U discloses "a cathode plate assembly of an electrochemical scale removal device", which includes a number of cathode plates arranged at intervals. Among them, concave side plates with the same thickness as the cathode plate are fixedly connected to the upper edge, lower edge and rear edge of the cathode plate. A rotating shaft that can rotate in the side plates is penetrated through the middle of the longitudinal bodies of a number of side plates; one end of the rotating shaft is connected to a transmission, and the power input end of the transmission is connected to a motor; a scraper group that can rotate with the rotating shaft to scrape the hard scale on the cathode plate is arranged side by side and at intervals on the rotating shaft. The scraper group includes a pair of scrapers arranged oppositely, and the pair of scrapers are respectively located on both sides of a cathode plate and are in contact with the cathode plate. The utility model not only realizes the mechanization of scraping the hard scale on the cathode plate, but also, through the transmission arranged between the rotating shaft and the motor, can change the rotation speed and torque of the motor according to the scraping situation of the scrapers on the hard scale, which is beneficial to the scraping of the hard scale. However, the result of this patent is only to scrape the already formed hard scale, and does not improve the efficiency of electrochemical scale removal.

[0008] The patent document with the publication number CN 217077074 U discloses "an electrochemical treatment device for circulating cooling water". The device includes a device main body, which is of a hollow structure. Inside the device main body, an inlet area, an electrochemical reaction area, a sludge precipitation area, and an outlet area are sequentially arranged along the flowing direction of the circulating cooling water. The inlet area, the electrochemical reaction area, the sludge precipitation area, and the outlet area are sequentially connected. A sludge collection and discharge area is also provided inside the device main body. The bottoms of the electrochemical reaction area and the sludge precipitation area are both connected to the sludge collection and discharge area. In the electrochemical reaction area, pluggable anode and cathode electrodes are vertically arranged perpendicular to the flowing direction of the circulating cooling water. Among them, the anode is a DSA electrode, and the cathode is a corrosion electrode. The utility model integrates the electrochemical scale removal, electrochemical sterilization and disinfection of circulating cooling water with sludge separation, has simple installation, convenient electrode replacement, and strong practicability. However, this method uses a DSA electrode and consumes relatively large amounts of electricity.

[0009] Li Sen, Wang Haifeng. Application of Electrochemical Method in Treating Cooling Circulating Water [J] (Chemical Industry Progress, 2013, 32(10): 2514 - 2517.). This paper proposed a new technology for treating cooling circulating water by electrochemical method. A self-made electrolysis system was used to perform high-frequency electric field treatment on simulated circulating water. The optimal process conditions were obtained by adjusting electrochemical parameters, and the process mechanism was analyzed in depth. Based on experimental research, a pilot test was carried out in an enterprise for this device to further verify and improve the process conditions. It was concluded that the treatment effect was the best when the current was 16 A, the voltage was 5 V, the plate spacing was 75 mm, and the flow rate was 1000 m3 / h. The research results showed that this process had excellent scale inhibition effects; it could make the aged scale soft and easy to peel off, showing good scale removal effects; it could effectively change the crystal form of sediments; it was convenient, efficient, green and environmentally friendly. However, there were certain limitations for the cases of relatively small or large water flow rates.

[0010] Guo Lina. Application Analysis of Electrochemical Scale Removal Technology in Circulating Cooling Water of Coking Wastewater Treatment [J] (Shanxi Chemical Industry, 2023, 11(43): 126 - 128.). Based on the electrochemical scale removal technology, this paper first designed the electrochemical experimental device required under this technical scheme; then, combined with theoretical analysis, the main index parameters of the electrochemical scale removal technical scheme were optimized and selected through a large number of experiments; finally, experiments were carried out using the optimized parameters. The experimental results showed that this electrochemical scale removal technology was significantly superior to the traditional chemical dosing treatment technology model in all main technical indicators, proving that the designed electrochemical scale removal technical scheme had certain advantages and was expected to have potential application value. However, this method was only limited to laboratory bench-scale tests, and the pilot test effect needed to be further verified. Summary of the Invention

[0011] The object of the present invention is to provide a device and method for efficient electrochemical scale removal in a clean circulating water system, to provide a new type of electrode with strong corrosion resistance, and to optimize the structure of the electrochemical reactor to make the scale inhibition and removal effect better, significantly improving the scale removal efficiency of the electrochemical method, with the characteristics of safety, environmental protection, high efficiency and cost reduction.

[0012] To achieve the above object, the present invention is implemented by the following technical solutions:

[0013] A device for efficient electrochemical scale removal in a clean circulating water system includes a cathode and an anode. The cathode is made of a high-entropy alloy material, and the anode is nano-zero-valent iron coated with SiO 2 ; the cathode and the anode are arranged alternately and coaxially, and the cathode plate and the anode plate have the same size.

[0014] Both the cathode and the anode are circular plates with a diameter of φ30 - 40 cm.

[0015] The cathode plate is evenly distributed with 10 - 20 round holes with a diameter of φ3 - 5 cm, and the anode plate is evenly distributed with 20 - 30 round holes with a diameter of φ2 - 3 cm.

[0016] The distance between the cathode and the anode plates is set to 10 - 20 cm.

[0017] There are 2 - 3 cathode plates and 2 - 3 anode plates.

[0018] The chemical components in the high-entropy alloy material are calculated by mass percentage as follows: Ti: 12.5% - 13.5%, Fe: 14% - 16%, Cu: 15% - 17%, Co: 15% - 18%, Si: 11% - 13%, Cr: 14% - 16%, Mo: 11% - 13%, O: 0.5% - 0.8%. The internal structure of this material is a columnar crystal structure, so that the high-entropy alloy material exhibits a unique function of releasing free electrons to the fluid medium and making the fluid medium produce a polarization effect extremely strongly.

[0019] The anode material is nano-zero-valent iron coated with SiO 2 , nano-zero-valent iron is inexpensive, has strong conductivity and corrosion resistance, and coating with SiO 2 can further enhance the corrosion resistance.

[0020] The cathode plate and the anode plate are arranged alternately coaxially. Such a structure can form three electrochemical reaction units, and these three units are connected in series, significantly enhancing the scale removal effect, and the use of circular plates for the electrode plates makes the electrochemical reaction more sufficient.

[0021] There are multiple round holes evenly distributed on the cathode plate, which can increase the contact area of the cathode, thereby improving the efficiency of the electrochemical reaction; there are multiple round holes evenly distributed on the anode plate, which can reduce the current density between the anode and cathode plates, reduce the possibility of hydrogen embrittlement of the cathode plate, and the aperture of the cathode plate is large while the aperture of the anode plate is small, which can accelerate the water flow rate between the plates and further remove the scaling ions.

[0022] A high-efficiency electrochemical scale removal method for a clean circulating water system specifically includes: the initial flow rate of the clean circulating water flowing through the device is: 10 m3 / h ≤ flow rate < 15 m3 / h, and after operating for 1 - 2 h, the flow rate is adjusted to: 15 m3 / h ≤ flow rate ≤ 20 m3 / h, the high flow rate operation time is 5 - 10 min, the high and low flow rates alternate, the starting voltage is set to 5 - 8 V, and after operating for 2 - 3 h, the voltage is adjusted to 3 - 5 V.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The present invention solves the problem that the cathode plate of the electrochemical reaction is prone to scaling, and significantly improves the rate of the electrochemical reaction. The electrochemical reaction device of the present invention has a simple structure, low treatment cost, high reaction efficiency, and completely solves the problem of scaling and corrosion in the circulating water system.

[0025] The present invention not only optimizes the structure of the electrochemical scale removal device, but also innovatively uses a high-entropy alloy material as the electrode, significantly enhancing the corrosion resistance of the electrode. When the fluid medium flows through the high-entropy alloy material at a certain flow rate, the high-entropy alloy material can release electrons to the fluid, change the electrostatic potential of the fluid, cause the fluid to have a polarization phenomenon, make the anions and cations in the fluid not easily combine to form scale, and at the same time can gradually dissolve and fall off the already caked scale, achieving the functions of scale prevention and scale removal. The present invention is economical, efficient, and has no secondary pollution. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the device for high-efficiency electrochemical scale removal of the clean circulating water system.

[0027] In the figure: ① is the cathode plate, and ② is the anode plate. Specific Embodiments

[0028] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further explains the specific embodiments of the present invention in conjunction with the embodiments. The following embodiments are used to specifically illustrate the content of the present invention. These embodiments are only general descriptions of the content of the present invention and do not limit the content of the present invention.

[0029] The present invention provides a device and method for high-efficiency electrochemical scale removal of a clean circulating water system, aiming to solve problems such as cathode scaling, high cost of anode materials, and low reaction efficiency in the electrochemical scale removal method. Using a high-entropy alloy material as the cathode, nano zero-valent iron coated with SiO2 As the anode, it can solve the problem of cathode scaling, enhance the corrosion resistance of the cathode, reduce costs, and improve the efficiency of scale removal by the electrochemical method. To this end, the technical solution adopted by the present invention is as follows:

[0030] A device for efficient electrochemical scale removal in a purified circulating water system, including a cathode and an anode. The cathode is made of a high-entropy alloy material, and the anode is nano-zero-valent iron coated with SiO 2 ; The cathode and the anode are alternated and arranged coaxially. The cathode plate 1 and the anode plate 2 have the same size.

[0031] Both the cathode and the anode are circular plates with a diameter of φ30 - 40 cm.

[0032] There are 10 - 20 circular holes with a diameter of φ3 - 5 cm evenly distributed on the cathode plate 1, and 20 - 30 circular holes with a diameter of φ2 - 3 cm evenly distributed on the anode plate 2.

[0033] The distance between the cathode and the anode plates is set to 10 - 20 cm.

[0034] There are 2 - 3 cathode plates 1 and 2 - 3 anode plates.

[0035] In the high-entropy alloy material, the chemical components are as follows by mass percentage: Ti: 13.5%, Fe: 14%, Cu: 17%, Co: 15%, Si: 11%, Cr: 16%, Mo: 13%, O: 0.5%.

[0036] A method for efficient electrochemical scale removal in a purified circulating water system specifically includes: The initial flow rate of the purified circulating water flowing through the device is: 10 m3 / h ≤ flow rate < 15 m3 / h. After running for 1 - 2 h, the flow rate is adjusted to: 15 m3 / h ≤ flow rate ≤ 20 m3 / h. The high flow rate running time is 5 - 10 min. The high and low flow rates alternate. The starting voltage is set to 5 - 8 V. After running for 2 - 3 h, the voltage is adjusted to 3 - 5 V.

[0037] Example 1:

[0038] 1) Use a high-entropy alloy material as the cathode and nano-zero-valent iron coated with SiO 2 as the anode;

[0039] 2) The cathode and the anode are alternated and arranged coaxially. There are a total of 2 cathode plates 1 and 2 anode plates 2. The sizes of the cathode and anode plates are the same, both being circular plates with a diameter of φ30 cm;

[0040] 3) There are 10 circular holes with a diameter of φ3 cm evenly distributed on the cathode plate 1, and 20 circular holes with a diameter of φ2 cm evenly distributed on the anode plate 2;

[0041] 4) The plate spacing is set to 10 cm, the flow rate is set to 10 m3 / h. After running for 1 h, the flow rate is adjusted to 15 m3 / h, and the high and low flow rates alternate. The residence time is set to 5 min, the starting voltage is set to 5 V, and the voltage is adjusted to 3 V after running for 2 h.

[0042] After the purified circulating water system processed by the above steps runs for 1 year, the average temperature at the outlet of the heat exchanger increases by about 1 °C, the heat exchange effect is enhanced, and there is no newly formed water scale after running for one year, so there is no need for cleaning, and it has a mild scale removal effect on the original water scale.

[0043] Example 2:

[0044] 1) Use a high-entropy alloy material as the cathode, and nano zero-valent iron coated with SiO 2 as the anode;

[0045] 2) The cathode and anode alternate and are placed coaxially. There are a total of 2 cathode plates 1 and 2 anode plates 2. The sizes of the cathode and anode plates are the same, both are circular plates with a diameter of φ35 cm;

[0046] 3) There are 15 round holes with a diameter of φ4 cm evenly distributed on the cathode plate 1, and 25 round holes with a diameter of φ2.5 cm evenly distributed on the anode plate 2;

[0047] 4) The plate spacing is set to 15 cm, the flow rate is set to 12 m3 / h. After running for 1.5 h, the flow rate is adjusted to 18 m3 / h, and the high and low flow rates alternate. The residence time is set to 8 min, the starting voltage is set to 7 V, and the voltage is adjusted to 4 V after running for 2.5 h.

[0048] After the purified circulating water system processed by the above steps runs for 1 year, the average temperature at the outlet of the heat exchanger increases by about 3 °C, the heat exchange effect is enhanced, and there is no newly formed water scale after running for one year, so there is no need for cleaning, and it has a mild scale removal effect on the original water scale.

[0049] Example 3:

[0050] 1) Use a high-entropy alloy material as the cathode, and nano zero-valent iron coated with SiO 2 as the anode;

[0051] 2) The cathode and anode alternate and are placed coaxially. There are a total of 2 cathode plates and 2 anode plates. The sizes of the cathode and anode plates are the same, both are circular plates with a diameter of φ40 cm;

[0052] 3) There are 20 round holes with a diameter of φ5 cm evenly distributed on the cathode plate 1, and 30 round holes with a diameter of φ3 cm evenly distributed on the anode plate 2;

[0053] 4) The plate spacing is set to 20 cm, the flow rate is set to 15 m3 / h. After running for 2 h, the flow rate is adjusted to 20 m3 / h, and the high and low flow rates alternate. The residence time is set to 10 min, the starting voltage is set to 8 V. After running for 3 h, the voltage is adjusted to 5 V.

[0054] After the purified circulating water system processed by the above steps runs for 1 year, the average temperature at the heat exchanger outlet rises by about 4 °C, the heat exchange effect is enhanced, and there is no newly formed water scale after running for one year, no cleaning is required, and there is a mild scale removal effect on the original water scale.

Claims

1. A highly efficient electrochemical descaling device for a clean circulating water system, characterized in that: It includes a cathode and an anode, wherein the cathode is made of a high entropy alloy material, and the anode is made of nano zero-valent iron coated with SiO2; the cathode and the anode are alternately arranged in a concentric axis, and the cathode plate and the anode plate have the same size.

2. The device for efficient electrochemical descaling of a clean circulating water system according to claim 1, characterized in that: The cathode and the anode are both circular plates with a diameter of φ30-40 cm.

3. The device for efficient electrochemical descaling of a clean circulating water system according to claim 1, characterized in that: The cathode plate is evenly distributed with 10 to 20 circular holes with a diameter of φ3 to 5 cm, and the anode plate is evenly distributed with 20 to 30 circular holes with a diameter of φ2 to 3 cm.

4. The device for efficient electrochemical descaling of a clean circulating water system according to claim 1, characterized in that: The distance between the cathode and anode plates is set to 10-20 cm.

5. The device for efficient electrochemical descaling of a clean circulating water system according to claim 1, characterized in that: The number of the cathode plates is 2 to 3, and the number of the anode plates is 2 to 3.

6. The device for efficient electrochemical descaling of a clean circulating water system according to claim 1, characterized in that: The chemical composition of the high entropy alloy material is calculated by mass percentage as follows: Ti: 12.5% ​​to 13.5%, Fe: 14% to 16%, Cu: 15% to 17%, Co: 15% to 18%, Si: 11% to 13%, Cr: 14% to 16%, Mo: 11% to 13%, and O: 0.5% to 0.8%.

7. A highly efficient electrochemical descaling method for a clean circulating water system, characterized in that: The method utilizes the device for efficient electrochemical descaling of a clean circulating water system as described in any one of claims 1 to 6, and specifically includes: the initial flow rate of the clean circulating water flowing through the device is: 10m3 / h≤flow rate<15m3 / h, the flow rate is adjusted to: 15m3 / h≤flow rate≤20m3 / h after running for 1 to 2 hours, the high flow rate operation time is 5 to 10 minutes, high and low flow rates are operated alternately, the starting voltage is set to 5 to 8V, and the voltage is adjusted to 3 to 5V after running for 2 to 3 hours.

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