A method for treating circulating cooling water by an internal circulation type electrochemical method

Abstract

The application discloses a circulating cooling water treatment method of an internal circulation type electrochemical method, which closely combines electrochemical softening and chemical softening to realize integration of hard removal and sterilization. On one hand, the method realizes three-stage softening of the circulating cooling water by combining a diaphragm electrolytic cell and a continuous crystallizer, and effectively improves the hard removal efficiency; the mixed flow discharged from the crystallizer is partially returned to the cathode area to realize scale suspension growth in the cathode area, avoid scale growth on the cathode plate, and effectively reduce scale body adhesion. On the other hand, the water discharged from the anode is fed into a temporary storage tank to improve the hydraulic retention time and fully sterilize and kill algae.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circulating cooling water treatment, and particularly relates to a circulating cooling water treatment method of an internal circulation type electrochemical method. BACKGROUND

[0002] Cooling water is a water resource used for cooling process medium and process equipment in industrial production process, and accounts for a large proportion in industrial water. Professionals have realized in the past that once-through cooling water greatly wastes water resources, is not conducive to environmental protection and sustainable development. The water-saving effect brought by circulating cooling water is obvious, and the water make-up rate can be effectively reduced and the sewage amount can be reduced, so it has become the consensus of professionals in the relevant industry to promote the use of circulating cooling water and pay attention to the corrosion and fouling problems in the circulating water system. The cooling water in the circulating water system is heated into hot water by the hot end after the cooler, and the hot water is basically not discharged, but returned to the system after being cooled for circulation, thereby greatly saving water. It is estimated that when the concentration multiple of circulating water reaches 3-5 times, the amount of make-up water can be reduced to 2%-3% of the amount of circulating water. Therefore, the promotion and development of circulating cooling water technology are of great significance for promoting industrial water saving and even near-zero discharge of industrial water.

[0003] Electrochemical scale removal technology is a new type of circulating water treatment technology, which can actively remove scale-forming factors from circulating water compared to traditional chemical methods, and can effectively increase the concentration multiple, greatly reduce the make-up water and sewage, and the treatment process is green, environmentally friendly and pollution-free. Electrochemical scale removal technology mainly aims at the scaling problem generated during the operation and management of circulating cooling water, and also has certain effect on corrosion, algae breeding and other problems, and usually utilizes a diaphragm to separate the qualities to effectively control the pH. The diaphragm electrolysis technology is to hinder the ion exchange between the electrolytic cells by adding an ion exchange membrane between the electrodes. In the diaphragm electrochemical scale removal technology, the neutralization reaction of H + and OH - between the electrolytic cells can be hindered to improve the current efficiency, and the principle is to release OH - by electrolyzing water, generate a high alkaline environment around the cathode to remove hardness and alkalinity ions, and generate oxidizing agents and H + in the anode area to inhibit the growth of algae and generate a dense oxidation film to prevent pipeline corrosion. Since the ion exchange membrane is expensive, and in actual application, the membrane surface structure may be damaged by scratching, so in the latest research, researchers try to use a cheap non-conductive diaphragm instead of an ion exchange membrane, and also achieve good blocking effect, showing great potential.

[0004] According to relevant research reports, compared with traditional electrochemical descaling, the current efficiency and descaling of diaphragm electrochemical descaling technology are greatly improved, which is conducive to promoting the industrial application of electrochemical descaling equipment. However, in practice, the running stability of the diaphragm electrochemical equipment is limited by the scaling of the equipment. The scale body will deposit and adhere to the surface of the cathode and the diaphragm, resulting in a significant increase in the voltage of the electrolytic cell, an increase in energy consumption, a decrease in current efficiency, a decrease in system processing efficiency, etc. Artificial or engineering means are needed to clean the scale in time, which greatly increases the consumption of manpower and material resources. In view of this problem, Chinese patent CN113754150B discloses "a stable running high-hardness water electrochemical descaling system and treatment process method", which adopts an electrochemical descaling method of "diaphragm electrochemical descaling + reinforced crystallization + scale-crystal separation". The alkaline water generated by the diaphragm electrolytic cell is mixed with raw water and then descaled in the reinforced crystallization device. Part of the alkaline softened water is neutralized with anode acidic water and then discharged, and part of the alkaline softened water is mixed with raw water and then returned to the electrolytic cell for treatment. This method can alleviate the scaling problem of the equipment to a certain extent and ensure the stability of the electrolytic cell operation. However, the treatment process only passes through the scale-crystal separation device once, and the cathode is still prone to scaling, which reduces the service life of the electrode. The mixing of cathode alkaline water and raw water can reduce the pH value of the water body, which in turn affects the descaling efficiency of the reinforced crystallization device. In addition, in the field of circulating cooling water treatment, the limited sterilization capacity of the diaphragm electrolytic cell is also considered to be an important problem limiting its development, i.e. the active substances and H + The sterilization effect in a limited time cannot meet the management requirements of circulating cooling water, which affects the integration degree of the circulating cooling water electrochemical equipment.

[0005] Therefore, although the diaphragm electrolysis technology has certain effects on descaling, sterilization and corrosion inhibition, it still has problems such as cathode scaling, limited sterilization capacity of anode electrolysis, and limited sterilization capacity of anode electrolysis. + active substances and H SUMMARY

[0006] The purpose of the present application is to provide a circulating cooling water treatment method of an internal circulation type electrochemical method to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a circulating cooling water treatment method of an internal circulation type electrochemical method, comprising the following steps,

[0008] S1: passing the circulating cooling water into a diaphragm electrolytic cell for electrolysis, the diaphragm electrolytic cell having an anode tank and a cathode tank separated by a diaphragm, the anode tank after electrolysis obtaining acidic water, and the cathode tank obtaining alkaline water;

[0009] S2: the alkaline water is filtered in a filter, and the filtered alkaline water and the circulating cooling water in step S1 are introduced into a continuous crystallizer to soften the circulating cooling water by an induced crystallization technology, so as to obtain crystal particles and alkaline softened water;

[0010] S3: the mixture of the crystal particles and the alkaline softened water is returned to the cathode tank of the diaphragm electrolytic cell in step S1 to strengthen the treatment capacity;

[0011] S4: the acidic water in step S1 is introduced into a sterilization temporary storage to increase the residence time and strengthen the sterilization capacity;

[0012] S5: after the alkaline softened water in step S2 and the acidic water in step S4 are mixed and neutralized, the mixture is filtered in a filter and then discharged.

[0013] Preferably, in step S1, the pH value of the acidic water ranges from 3.0 to 6.5, and the pH value of the alkaline water ranges from 8.0 to 12.0.

[0014] Preferably, in step S2, the continuous crystallizer is an internal circulating fluidized bed reactor, and no medicament needs to be added when the internal circulating fluidized bed reactor processes the alkaline water and the raw water in step S1.

[0015] Preferably, in step S2, the average particle size of the crystal particles is not less than 1 mm, and the pH value of the alkaline softened water ranges from 8.0 to 10.0.

[0016] Preferably, in step S3, the backflow flow rate is 50% to 200% of the water flow rate.

[0017] Compared with the prior art, the present application has the beneficial effects that: the present application is aimed at the problems of cathode fouling and limited sterilization capacity of anode effluent, and the treatment efficiency of the system is improved by reasonably configuring the solid-liquid flow in the system. The present application constructs a crystallizer-like environment in the cathode tank of the diaphragm electrolytic cell, which is conducive to inducing crystallization. The mixed flow of the crystal particles and the alkaline softened water discharged from the crystallizer is used as a new crystal induction carrier, and the electrochemical reaction in the cathode tank forms a double driving force to cooperatively degrade the hardness and alkalinity in the circulating cooling water; in the crystallizer, the filtered cathode effluent is used as an alkaline medicament to soften the circulating cooling water, and the OH - As an alkaline medicament, the mixed flow of the crystal particles and the alkaline softened water discharged from the crystallizer is used as a new crystal induction carrier, and the electrochemical reaction in the cathode tank forms a double driving force to cooperatively degrade the hardness and alkalinity in the circulating cooling water; in the crystallizer, the filtered cathode effluent is used as an alkaline medicament to soften the circulating cooling water, and the OH -The utilization rate and the processing efficiency of the system are improved, and the mixed flow of the crystal particles and the alkaline softened water in the crystallizer is partially returned to the cathode tank of the diaphragm electrolytic cell as a new crystal carrier, so that the electrochemical and chemical softening are closely linked. On the one hand, the three-stage softening of the circulating cooling water is realized by combining the diaphragm electrolytic cell and the continuous crystallizer, and the softening efficiency is effectively improved; the mixed flow discharged from the crystallizer is partially returned to the cathode area, the scale suspension growth of the cathode area is realized, and the scale growth on the cathode plate is avoided, so that the scale body adhesion is effectively reduced. On the other hand, the anode outlet water enters the temporary storage tank, the hydraulic retention time is improved, and the sterilization and algae killing are sufficient. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present application.

[0019] Figure 2 It is a water quality data diagram of the circulating cooling water to be treated.

[0020] Figure 3 It is a data diagram of the primary electrochemical softened water.

[0021] Figure 4 It is a data diagram of the secondary electrochemical softened water

[0022] In the figure: 1 diaphragm electrolytic cell, 2 filtering device one, 3 sterilization temporary storage tank, 4 continuous crystallizer, 5 neutralization tank, 6 filtering device two. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0024] Cooling water is a water resource used for cooling process medium and process equipment in industrial production process, and accounts for a large proportion in industrial water. Professionals have realized in the past that direct-flow cooling water greatly wastes water resources, is not conducive to environmental protection and sustainable development. The water-saving effect brought by circulating cooling water is obvious, and the water supplement rate and the sewage discharge amount can be effectively reduced, so it has become the consensus of relevant industry professionals to promote the use of circulating cooling water and pay attention to the corrosion and scaling problems in the circulating water system. The cooling water in the circulating water system is heated into hot water by the hot end after passing through the cooler, and the hot water is basically not discharged, but returned to the system after being cooled for recycling, thereby greatly saving water. According to estimation, when the concentration multiple of the circulating water reaches 3-5 times, the amount of supplementary water can be reduced to 2%-3% of the amount of circulating water. Therefore, the promotion and development of circulating cooling water technology are of great significance for promoting industrial water saving and even near-zero discharge of industrial water.

[0025] Electrochemical water treatment technology is a new type of circulating cooling water treatment technology, which can effectively improve the concentration ratio, reduce the make-up water and blowdown water compared with the chemical method. Although this method has certain effect on scale removal, sterilization and corrosion inhibition required by the stability of circulating cooling water quality, it exposes problems such as cathode scale and limited sterilization capacity of anode effluent.

[0026] Therefore, in view of the technical problems of scale formation of equipment and limited sterilization capacity of electrochemical method, the present application provides a circulating cooling water treatment method which can multi-stage soften and reduce scale body adhesion, strengthen the sterilization capacity of anode, and has low operation cost and convenient management and maintenance, has high economic, social and environmental benefits, and good application prospect.

[0027] Please refer to Figure 1 , the present application provides a technical solution: a circulating cooling water treatment method of internal circulation type electrochemical method, comprising the following steps:

[0028] S1, circulating cooling water is introduced into a diaphragm electrolytic cell for electrolysis, the diaphragm electrolytic cell has an anode tank and a cathode tank separated by a diaphragm, the anode tank after electrolysis obtains acidic water, and the cathode tank obtains alkaline water;

[0029] S2: the alkaline water is introduced into a filter for filtration, and the filtered alkaline water and the circulating cooling water of step S1 are introduced into a crystallizer to soften the circulating cooling water by induced crystallization technology, to obtain crystal particles and alkaline softened water;

[0030] S3: the mixed solution of the crystal particles and the alkaline softened water is flowed back to the cathode tank of the diaphragm electrolytic cell of step S1 to strengthen the treatment capacity;

[0031] S4: the acidic water of step S1 is introduced into a sterilization temporary storage to improve the residence time to strengthen the sterilization capacity;

[0032] S5: after the alkaline softened water of step S2 and the acidic water of step S4 are mixed and neutralized, they are introduced into a filter for filtration and then discharged.

[0033] In step S1, the pH value of the acidic water ranges from 3.0 to 6.5, and the pH value of the alkaline water ranges from 8.0 to 12.0.

[0034] The diaphragm electrolytic cell divides the electrolytic cell into an anode tank and a cathode tank by using a diaphragm with barrier effect. During the electrolysis process, the diaphragm material has certain ion selective permeability, that is, only allows certain specific ions to pass through, while prevents other ions or molecules from passing through. For example, some diaphragms only allow hydrogen ions (H + ) or hydroxyl ions (OH -) while preventing the passage of other ions or molecules. This ensures that the ion concentration in the cathode and anode regions remains stable during the electrolysis process, avoiding material exchange. In the present invention, a diaphragm electrolytic cell is used to electrolyze water in the anode tank and cathode tank regions to produce hydrogen ions (H + ) and hydroxide ions (OH - ), respectively. In the anode tank, other anions in water molecules lose electrons and undergo oxidation, and because the concentration of hydrogen ions in water is high, the water in the anode tank is acidic. In the cathode tank, hydrogen ions gain electrons and undergo reduction to produce hydroxide ions, and the water in the cathode tank is alkaline. Therefore, by using a diaphragm electrolytic cell to electrolyze the circulating cooling water, the separation of acidic water and alkaline water is achieved, allowing for different treatments of the acidic water and alkaline water in the subsequent process.

[0035] In step S2, the diameter of the crystalline particles is not less than 1 mm, and the pH of the alkaline softened water ranges from 8.0 to 11.0;

[0036] The hardness of water mainly refers to the concentration of dissolved calcium and magnesium ions in water, while the alkalinity of water refers to the total amount of substances that can neutralize acids in water. In the process of electrochemical softening, calcium and magnesium ions migrate to the cathode tank under the combined action of diffusion and electric field, and react with alkalinity ions to form scale, which preliminarily reduces the hardness of water. However, over time, the deposition of scale will be difficult to completely remove, and will reduce the current efficiency and mass transfer efficiency, making it difficult for the diaphragm electrolytic cell to operate stably for a long time. The formation of scale, i.e. the process of calcium and magnesium ions in water combining with alkalinity to precipitate from the solution, is a crystallization process. Generally, the formation and precipitation of crystals undergo two stages, namely the generation of crystal nuclei and the growth of crystals, with the former being mainly controlled by thermodynamic conditions and the latter being mainly controlled by kinetic conditions. Based on the above crystallization theory, the induced crystallization softening technology first loads a certain amount of crystal seeds into the reactor, and then adds alkaline reagents to react with calcium and magnesium ions to produce crystalline products. The crystalline products then adhere to the surface of the crystal seeds and gradually grow as the system continues to operate. Finally, when the crystal seeds grow to a certain size, they are discharged from the reactor, while a portion of new crystal seeds are supplemented. Related studies have shown that the growth of scale crystals is mainly influenced by factors such as pH, supersaturation, crystal seed size, flow rate, etc. The continuous crystallizer is an internal circulating fluidized bed reactor, which is a multiphase flow reactor with the advantages of simple structure, good mixing and mass transfer performance, easy operation and maintenance, and low energy consumption per unit volume.

[0037] In step S3, the reflux liquid flow rate is 50% to 200% of the water inlet flow rate;

[0038] The formation of scale is a process of crystal nucleation and growth, and there are two nucleation methods, heterogeneous nucleation and homogeneous nucleation. Heterogeneous nucleation occurs on the surface of the electrode or equipment, while homogeneous nucleation occurs in the solution. In the conventional electrochemical softening process, because the cathode electrode surface is where OH- The first place of the supersaturated environment near the cathode surface makes the heterogeneous nucleation dominant, which is not conducive to the continuous operation of the electrode. The conventional crystallizer is a device for converting solutes in the solution into crystal particles, and the crystallization technology can help the crystal of the alkaline water to nucleate on the surface of the loaded seed crystal, therefore, the mature crystal particles generated by the continuous crystallizer are used as new seeds, the deposition of the scale can be effectively avoided, the rapid solid-liquid separation can be realized, the hardness and alkalinity of the water are further reduced, the processing efficiency of the system is improved, and the stable operation of the system is avoided due to the deposition of the scale.

[0039] In step S4, the residence time of the acid water is not less than 10 min;

[0040] The common microorganisms in the circulating cooling water system include bacteria, algae, fungi and insects, and the hazards to the system mainly include adhesion and corrosion, and can also aggravate other non-microbial fouling and corrosion. In the medicament method, the medicament for controlling the breeding of microorganisms is called bactericide, and there is a bactericidal effect and a bacteriostatic effect. The bactericidal effect generally shows that the cells cannot divide, the life activities are destroyed, and the number of microorganisms is directly reduced; the bacteriostatic effect generally shows that the normal life activities of microorganisms are difficult to continue, and the number of microorganisms does not increase obviously. The bactericidal or bacteriostatic effect of the medicament method is mainly related to the properties of the medicament, the use concentration, the pH, the temperature and the action time. The bactericidal effect of the electrochemical circulating water treatment technology is generally considered to be the killing effect of H + and oxidants on microorganisms, but due to the mass transfer limitation, the killing ability of the active substances generated by electrolysis on microorganisms in a limited time is limited, and measures may also be taken to further kill the microorganisms in the circulating water. The method provided by the present application realizes the step-by-step softening of the cathode effluent, and accordingly, the residence time of the anode effluent is increased, and the bactericidal capacity of the anode effluent can be effectively improved.

[0041] In summary, the present application provides a circulating cooling water treatment method of an internal circulation type electrochemical method, which is aimed at the problems of cathode scaling and limited bactericidal capacity of anode effluent, and the solid-liquid flow in the system is reasonably configured to improve the processing efficiency of the system. The present application constructs a crystallizer-like environment conducive to induced crystallization in the cathode tank of the diaphragm electrolytic cell, and uses the OH - As an alkaline medicament, the mixed flow of the crystal particles discharged by the crystallizer and the alkaline softened water is used as a new crystal induction carrier, and the double driving force formed by the electrochemical reaction of the cathode tank is used to cooperatively degrade the hardness and alkalinity in the circulating cooling water; in the crystallizer, the filtered cathode effluent is used as an alkaline medicament to soften the circulating cooling water, and the OH -The utilization rate and the processing efficiency of the system are improved, and the mixed flow of the crystal particles and the alkaline softened water in the crystallizer is partially returned to the cathode tank of the diaphragm electrolytic cell as a new crystal carrier, so that the electrochemistry and the chemical softening are closely linked. On the one hand, the three-stage softening of the circulating cooling water is realized by combining the diaphragm electrolytic cell and the continuous crystallizer, and the softening efficiency is effectively improved; the mixed flow discharged from the crystallizer is partially returned to the cathode area to realize the scale suspension growth in the cathode area, so that the scale growth on the cathode plate is avoided, and the scale body adhesion is effectively reduced. On the other hand, the anode effluent enters the temporary storage tank to improve the hydraulic retention time, so that the sterilization and algae killing are fully realized.

[0042] Example 1

[0043] The circulating cooling water is pumped into the diaphragm electrolytic cell 1, and the circulating cooling water generates acidic water and alkaline water in the anode tank and the cathode tank under the electrolysis of the diaphragm electrolytic cell 1. The acidic water is introduced into the sterilization temporary storage tank 3 to prolong the retention time and improve the sterilization capacity. On the other hand, the alkaline water is introduced into the filtering device one 2 to realize the solid-liquid separation, and then the filtered alkaline water is used as an alkaline agent to soften the circulating cooling water raw water in the crystallization device of the continuous crystallizer 4. After the reaction, scale crystal particles and water are formed, the hardness and alkalinity of the water are reduced, the scale crystal particles are discharged from the bottom and partially returned to the cathode chamber of the diaphragm electrolytic cell 1. Finally, the treated water and the anode effluent in the sterilization temporary storage tank 3 are mixed and neutralized in the neutralization tank 5, and the effluent is filtered in the filtering device two 6 and then discharged.

[0044] Example 2

[0045] The water quality data of the circulating cooling water to be treated are as shown in Table 1. Figure 2

[0046] The steps of removing hardness and alkali from the above-mentioned circulating cooling water to be treated are as follows:

[0047] Under the condition that the water inflow is 10.0 m 3 / h, the circulating cooling water to be treated is introduced into the diaphragm electrolytic cell 1 for electrolysis. The diaphragm electrolytic cell 1 adopts a direct current power supply voltage of 9.0 V, and the diaphragm in the diaphragm electrolytic cell 1 divides the electrolytic cell into an anode tank and a cathode tank. After the electrolysis treatment, the pH range of the anode tank effluent reaches 3.0-6.5, and the pH range of the cathode tank effluent reaches 9.0-12.0. Under the condition that the anode tank effluent flow is 5.0 m 3 / h, the anode tank effluent is introduced into the sterilization temporary storage tank 3 to strengthen the sterilization capacity. The electrolysis produces active substances and H + The sterilization rate is greater than 50% under the retention time of not less than 10 min.

[0048] In the cathode tank, the electrolytic water produces OH - ​The pH value is increased, and the alkalinity ions and hardness ions in the water are nucleated and form scale on the seed crystal surface in the high pH environment. After electrolysis treatment, the total hardness removal rate reaches 80%. In order to avoid scale deposition on the electrode and further soften the circulating cooling water raw water, the cathode tank effluent is filtered and then introduced into the continuous crystallizer 4 under the condition that the cathode tank effluent flow is 5 m 3 / h. The circulating cooling water raw water with a flow of 5 m 3 / h is softened by the induced crystallization technology. After the reaction in the continuous crystallizer 4, the effluent pH value reaches 10, the hardness removal rate reaches 70%, and the alkalinity removal rate reaches 50%. The average particle size of the crystal particles at the bottom of the continuous crystallizer 4 is greater than 1 mm. At the same time, the crystal particle mixed stream discharged from the bottom of the continuous crystallizer 4 is partially returned to the cathode tank of the diaphragm electrolysis tank 1 at a flow rate of 5 m 3 / h to enhance the treatment capacity. The softened water and the anode effluent passing through the sterilization temporary storage device 3 are mixed and neutralized, filtered by the filtering device 2, and then discharged.

[0049] It is worth noting that different flow rates of water entering the continuous crystallizer 4 will affect the removal effect of the reaction. When the flow rate is too fast, most of the calcium and magnesium ions will flow out with the water flow without homogeneous nucleation and growth. When the flow rate is too slow, the removal efficiency will also be greatly reduced due to the decrease in flow rate. Therefore, the appropriate flow rate should be selected according to the actual application situation.

[0050] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A circulating cooling water treatment method using an internal circulation electrochemical method, characterized by: Contains the following steps, S1: passing circulating cooling water into a diaphragm electrolyzer for electrolysis, wherein the diaphragm electrolyzer has an anode tank and a cathode tank separated by a diaphragm, and after electrolysis, the anode tank produces acidic water and the cathode tank produces alkaline water; S2: passing the alkaline water into a filter for filtering, passing the filtered alkaline water and the circulating cooling water in step S1 into a continuous crystallizer, softening the circulating cooling water by induced crystallization technology to obtain crystal particles and alkaline softened water; S3: returning the mixture of the crystal particles and alkaline softened water to the cathode tank of the diaphragm electrolytic cell in step S1 to enhance the processing capacity; S4: passing the acidic water in step S1 into a temporary sterilization storage vessel to increase the residence time to enhance the sterilization ability; S5: The alkaline softened water in step S2 and the acidic water in step S4 are mixed and neutralized, passed into a filter for filtration, and then discharged.

2. The method for treating circulating cooling water by an internal circulation electrochemical method according to claim 1, characterized in that: In step S1, the pH value of the acidic water is in the range of 3.0-6.5, and the pH value of the alkaline water is in the range of 8.0-12.

0.

3. The method for treating circulating cooling water by an internal circulation electrochemical method according to claim 1, characterized in that: In step S2, the continuous crystallizer is an internal circulation fluidized bed reactor. When the internal circulation fluidized bed reactor treats the alkaline water and raw water in step S1, no reagent needs to be added.

4. The method for treating circulating cooling water by an internal circulation electrochemical method according to claim 1, characterized in that: In step S2, the average particle size of the crystal particles is not less than 1 mm, and the pH range of the alkaline softened water is 8.0-10.

0.

5. The method for treating circulating cooling water by an internal circulation electrochemical method according to claim 1, characterized in that: In step S3, the reflux flow rate is 50%-200% of the inlet flow rate.

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