Water quality stabilizing treatment method for EB furnace chamber circulating cooling water system

Abstract

The invention discloses a water quality stabilizing treatment method for an EB furnace chamber circulating cooling water system, and belongs to the technical field of smelting equipment maintenance. The method comprises the steps of chemical cleaning, water replacement and water replenishing blending, system pre-filming treatment, corrosion and scale inhibition treatment and microorganism control. Aiming at corrosion control of a carbon steel furnace chamber of the EB furnace, the invention provides a'cleaning, pre-filming, corrosion inhibition and sterilization 'integrated treatment process which is a comprehensive water quality stabilization treatment method considering microbial inhibition and system pre-filming; meanwhile, a mixed water replenishing strategy and coupon pH linkage monitoring are combined, so that the corrosion rate of a cooling water system of the EB furnace is reduced by 95% or above, corrosion of a carbon steel furnace chamber is fundamentally controlled, and water is clear and stable for a long time; and the device has remarkable progress and practical advantages in the aspects of prolonging the service life of equipment, improving the production safety, reducing the energy consumption and saving the comprehensive maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical equipment maintenance technology, and relates to cooling water treatment technology for the circulating system of carbon steel smelting furnace, specifically to a water quality stabilization treatment method for the circulating cooling water system of EB furnace. Background Technology

[0002] An electron beam cold hearth furnace (EB furnace) is a high-temperature equipment that melts materials by bombarding them with an electron beam in a high-vacuum environment. Its cold hearth, crystallizer, electron gun chamber, and furnace chamber are typically cooled by a circulating cooling water system. Because the temperature inside the EB furnace is extremely high during operation, the cooling water system needs to operate continuously for a long time, and the stability of the water quality directly affects the equipment's lifespan, production safety, and product quality.

[0003] Currently, EB furnace cooling water systems are generally maintained through periodic replacement of softened water and cleaning of heat exchangers. However, residual water in the system pipes and furnace chamber cannot be completely drained during water changes, leading to rapid deterioration of water quality and a dark yellow hue. The carbon steel furnace chamber undergoes severe electrochemical corrosion under the influence of dissolved oxygen and chloride ions, generating rust that dissolves in the water or deposits in the pipes. Simultaneously, the cooling system lacks effective sterilization measures, resulting in the proliferation of microorganisms and the formation of biological slime, accelerating equipment and pipe corrosion and damage. Furthermore, traditional methods cannot perform deep cleaning and pre-filming of the system without shutting down the plant, resulting in limited maintenance effectiveness, impacting production continuity, and ultimately severely affecting equipment lifespan, production safety, and product quality.

[0004] Therefore, there is an urgent need for a comprehensive water quality stabilization treatment method for the EB furnace cooling water system to achieve corrosion control, microbial inhibition, and long-term safe and stable operation of the system. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a water quality stabilization treatment method for the circulating cooling water system of EB furnace chamber, and to solve the technical problems of severe equipment corrosion, easy growth of microorganisms in the system, rapid water quality deterioration, and high maintenance costs in the existing technology of using EB furnace circulating cooling water system.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This embodiment provides a water quality stabilization treatment method for the circulating cooling water system of the EB furnace chamber, such as... Figure 1 As shown, the method specifically includes the following steps: Step 1, Chemical Cleaning: With the cooling system running continuously, add a multi-functional cleaning agent to the circulating water. The dosage of the multi-functional cleaning agent is calculated based on the system's water volume, with a specific concentration of 5–10 g / L. After adding the cleaning agent, keep the system water circulating for 24–48 hours, during which time monitor the pH value and water color changes. When the pH value stabilizes at 4–5 and the water color no longer darkens, it indicates that the reaction is complete and the cleaning is finished.

[0007] Step 2, Water Replacement and Replenishment: The cleaning waste liquid is discharged, and the remaining cleaning waste liquid in the equipment is fully neutralized with a slightly alkaline aqueous solution with a pH of 7.5 to 8.5. Then, the system is subjected to a large-scale water replacement process to flush out the residue in the system. When replenishing water, tap water and softened water are mixed at a volume ratio of (1.5 to 2.5):1 to ensure that the replenishment water contains an appropriate amount of calcium and magnesium ions to provide conditions for subsequent pre-filming.

[0008] Step 3, System pre-filming treatment: Add a pre-filming agent to the system. The pre-filming agent complexes with calcium and magnesium ions in the cooling water to form a deposit film on the metal surface. The dosage is 0.3 to 0.8 wt% of the system's water volume. Control the pH value of the circulating water at 9.0 to 10.0 and circulate continuously for 36 to 48 hours to form a dense protective film on the metal surface. After the pre-filming is completed, perform water replacement again until the pH value stabilizes at 8.5 to 9.0.

[0009] Step 4, corrosion and scale inhibition treatment: Add corrosion and scale inhibitors to the system. The corrosion and scale inhibitors are phosphorus-free and environmentally friendly. The initial dosage is 0.15 to 0.25 wt% of the system's water volume. After the system is running normally, continue to add corrosion and scale inhibitors daily to control the pH value of the circulating water between 8.0 and 9.5. Regularly hang carbon steel and stainless steel hanging plates to monitor corrosion.

[0010] Step 5, Microbial Control: Add a non-oxidizing bactericide and algaecide 1-2 times per month. The non-oxidizing bactericide and algaecide is composed of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) (molar ratio 3:1). The dosage is 0.05-0.1 wt% of the system's water volume. After addition, run the system for 6-12 hours for sterilization, then drain the wastewater and add softened water to the normal water level.

[0011] Step Six, System Monitoring and Maintenance: Regularly test water quality parameters such as pH, turbidity, and conductivity; inspect or clean plate heat exchangers every 1-2 years; calibrate pH meters regularly to ensure accurate measurements.

[0012] The present invention also has the following technical features: Specifically and optionally, if the system is heavily contaminated, the circulating cooling water system of the EB furnace should be replaced multiple times before chemical cleaning to remove as much corrosion products such as rust, trace amounts of scale and biological slime that have accumulated in the cooling system over a long period of time, so that the water quality can be initially normalized.

[0013] The beneficial technical effects of this invention compared to the prior art are as follows: (I) This invention addresses corrosion control in the carbon steel furnace chamber of an EB furnace by proposing an integrated treatment process of "cleaning + pre-filming + corrosion inhibition + sterilization." This is a comprehensive water quality stabilization method that considers microbial inhibition and system pre-filming. Simultaneously, by combining a mixed water replenishment strategy with pH-linked monitoring of the coated plates, it achieves a reduction of over 95% in the corrosion rate of the EB furnace cooling water system, fundamental control of carbon steel furnace chamber corrosion, and long-term clear and stable water quality. Compared to traditional single-water-changing cleaning methods, this invention offers significant improvements and practical advantages in extending equipment lifespan, enhancing production safety, reducing energy consumption, and saving overall maintenance costs.

[0014] (II) The "tap water + softened water" mixed water replenishment method adopted in this invention ensures that the cooling water system contains an appropriate amount of film-forming substances (such as Ca). 2+ This ensures that the pre-filming agent can form a film smoothly.

[0015] (III) This invention uses “coated plate monitoring + real-time pH control” to dynamically monitor and adjust the corrosion and water quality of carbon steel furnace chambers, thereby achieving visualized and quantitative management of corrosion control and water quality.

[0016] (IV) The present invention can clean the system without stopping the machine and maintain stable water quality. This is not only applicable to general conventional working conditions, but also adaptable to the special working conditions of EB furnace high temperature, high voltage and continuous production. Attached Figure Description

[0017] Figure 1 This is a flowchart of the water treatment process.

[0018] Figure 2 This refers to rust that has dissolved in the water due to corrosion in the cooling pipes.

[0019] Figure 3 Comparison of corrosion of hanging plates after 3 days using traditional methods (left: stainless steel; right: carbon steel).

[0020] Figure 4 The image shows a comparison of corrosion of the hanging plate after 3 days of suspension in Example 1 (left: stainless steel; right: carbon steel).

[0021] Figure 5 For monitoring the pH value of water after chemical cleaning.

[0022] Figure 6 pH value monitoring after water quality stabilization treatment.

[0023] The technical solution of the present invention will be further described below with reference to the embodiments. Detailed Implementation

[0024] It should be noted that all reagents and systems used in this invention, unless otherwise specified, are those known in the art. For example: The multi-functional cleaning agent uses products known in existing technology and was purchased from Shandong Ludong Environmental Protection Technology Co., Ltd. The product name is LD-QX002 Multi-functional High-efficiency Cleaning Agent, which is an acidic liquid mainly composed of inorganic acid, organic acid and various compound polymers.

[0025] The pre-filming agent used is a product known in the existing technology, purchased from Shandong Ludong Environmental Protection Technology Co., Ltd., with the trade name LD-QX001 Cleaning Pre-filming Agent, which is mainly composed of phosphonates and active ingredients.

[0026] The corrosion and scale inhibitor used is a product known in the existing technology, purchased from Shandong Ludong Environmental Protection Technology Co., Ltd., with the trade name LD-ZG003 Green Environmental Protection Phosphorus-Free Corrosion and Scale Inhibitor.

[0027] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0028] Example 1 This embodiment provides a water quality stabilization treatment method for a circulating cooling water system in an EB square furnace chamber. The furnace chamber has dimensions of 4.0*2.7*2.3m and a volume of approximately 25m³. 3 15 m³ of cooling water for the furnace chamber 3 The EB furnace's circulating cooling system has been operating for over a year. The water is dark yellow, the carbon steel furnace chamber appears to be corroded, the stainless steel furnace plates show no corrosion, while the carbon steel furnace plates are severely corroded (e.g., ...). Figure 2 (As shown). The method specifically includes the following steps: Step 1, Chemical Cleaning: With the cooling system running continuously, direct traffic to approximately 15 m 3 Add 100 kg of multi-purpose cleaning agent to the circulating water at a concentration of approximately 6.6 g / L; after adding the cleaning agent, maintain the system water circulation for 24 hours, during which time monitor the pH value to ensure it remains stable at 4.73 (e.g., ...). Figure 5 As shown in the image, the color is pale yellow, indicating that the reaction is complete and the cleaning process is finished.

[0029] Step 2, Water Replacement and Replenishment: The cleaning waste liquid is discharged, and any remaining cleaning waste liquid in the equipment is fully neutralized with a slightly alkaline aqueous solution with a pH of 8.0. Then, a large-scale water replacement process is performed to flush out any residue from the system. When replenishing water, tap water and softened water are mixed at a volume ratio of 2:1 to ensure that the replenishment water contains appropriate amounts of calcium and magnesium ions, providing conditions for subsequent pre-filming.

[0030] Step 3, System pre-filming treatment: Add 75 kg of pre-filming agent to the system, which is 0.5 wt% of the system's water volume. This allows the pre-filming agent to fully complex with calcium and magnesium ions in the cooling water, forming a deposit film on the metal surface and adhering to it. Control the pH of the circulating water to 9.6 and circulate continuously for 48 hours to form a dense protective film on the metal surface. After the pre-filming is completed, perform water replacement again until the pH stabilizes at 8.6.

[0031] Step 4, corrosion and scale inhibition treatment: Add 25 kg of corrosion and scale inhibitor to the system initially, at a rate of 0.17 wt% of the system's water volume. The system pH rises to 10.22. After the system is running normally, continue adding 3–5 kg of corrosion and scale inhibitor daily to maintain the circulating water pH at 8.2–9.0. Regularly suspend carbon steel and stainless steel fins to monitor corrosion. In this embodiment, as... Figure 4 As shown, after suspending carbon steel and stainless steel plates for 3 days, the carbon steel showed no visible corrosion. In contrast, the corrosion results of the plates after suspending using the traditional method for 3 days were as follows: Figure 3 As shown.

[0032] Step 5, Microbial Control: A non-oxidizing bactericide and algaecide is added 1-2 times per month, with each addition being 10 kg, which is 0.07 wt% of the system's water volume. The non-oxidizing bactericide and algaecide consists of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) (molar ratio 3:1). After addition, sterilization is performed 10 hours after operation, followed by 1.5 m³ of wastewater discharge. 3 Then, add softened water to the normal water level.

[0033] Verification of the effect of Example 1: After adopting the method of this example, the corrosion of carbon steel was effectively controlled, and the corrosion rate was less than 0.125 mm / a; the water quality gradually became clear, and the turbidity dropped to below 10 ppm; the system operated stably, the heat exchange efficiency was improved, and the production continuity was enhanced.

[0034] Example 2 This embodiment provides a water quality stabilization treatment method for the circulating cooling water system of the EB furnace chamber. Based on Embodiment 1, this method further includes the following steps: Step Six, System Monitoring and Maintenance: Monitor pH, turbidity, and conductivity parameters daily, and calibrate the detectors regularly; add bactericide twice a month (in summer) or once a month (in other seasons); check the corrosion of the plate fins every six months; and chemically clean the plate heat exchanger every two years.

[0035] Verification of the effect of Example 2: After the system was running for 18 months using the method of this example, there were no new corrosion spots in the furnace chamber, the water was clear, the equipment was running normally, and no unplanned shutdowns caused by the cooling water system occurred.

[0036] Example 3 This embodiment provides a water quality stabilization treatment method for a circulating cooling water system in an EB circular furnace chamber. The furnace chamber has dimensions of φ3*3 m and a volume of approximately 21.2 m³. 3 12 m³ of cooling water for the furnace chamber 3 The EB furnace circulating cooling system had been operating for over two years, resulting in corrosion of the carbon steel furnace chamber and a dark yellow cooling water quality. In this embodiment, the system was severely contaminated; therefore, a large-scale pretreatment was added before chemical cleaning. Specifically, the cooling system underwent three large water changes to remove as much rust and other corrosion products, trace amounts of scale, and biological slime accumulated over time, thus initially normalizing the water quality. This method includes the following steps: Step 1, Chemical Cleaning: Add 108 kg of multifunctional cleaning agent to the cooling circulating water at a concentration of approximately 9 g / L; after adding the cleaning agent, keep the system water circulating for 40 hours, and monitor the pH value to ensure it stabilizes at 4.61 after the reaction is complete, turning a pale yellow color.

[0037] Step 2, Water Replacement and Replenishment: The cleaning wastewater is discharged, and any remaining cleaning wastewater in the equipment is fully neutralized with a slightly alkaline aqueous solution with a pH of 8.0. Then, a large-scale water replacement process is performed to thoroughly remove the cleaning wastewater and suspended solids. When replenishing water, tap water and softened water are mixed at a volume ratio of 2.2:1 to ensure the replenishment water contains appropriate amounts of calcium and magnesium ions, providing conditions for subsequent pre-filming.

[0038] Step 3, System pre-filming treatment: Add 72 kg of pre-filming agent to the system, which is 0.6 wt% of the system's water volume. This allows the pre-filming agent to fully complex with calcium and magnesium ions in the cooling water, forming a deposited film on the metal surface and adhering to it. Control the circulating water pH to 9.4 and circulate continuously for 40 hours to form a dense protective film on the metal surface. After the pre-filming process, perform another water replacement until the pH stabilizes at 8.7 (e.g., ...). Figure 6 (As shown).

[0039] Step 4, corrosion and scale inhibition treatment: 25 kg of corrosion and scale inhibitor was added to the system initially, at a rate of 0.21 wt% of the system's water volume, causing the system pH to rise to 10.4. After the system was running normally, 3–5 kg of corrosion and scale inhibitor was added daily to maintain the circulating water pH at 8.4–9.0. Carbon steel and stainless steel suspenders were periodically suspended to monitor corrosion. In this embodiment, the carbon steel and stainless steel suspenders were removed after 3 days, and no visible corrosion was observed on the carbon steel.

[0040] Step 5, Microbial Control: A non-oxidizing bactericide and algaecide was added twice a month, with each addition being 8 kg, which is 0.07 wt% of the system's water volume. Sterilization was performed 10 hours after addition, followed by a 1.2 m³ wastewater discharge. 3 Then, add softened water to the normal water level.

[0041] Verification of the effect of Example 3: After adopting the method of this example, the corrosion of carbon steel was effectively controlled, and the corrosion rate was less than 0.125 mm / a; the water quality gradually became clear, and the turbidity dropped to below 12 ppm; the system operated stably, the heat exchange efficiency was improved, and the continuity of production was enhanced. Example 4 This embodiment provides a water quality stabilization treatment method for the circulating cooling water system of an EB circular furnace chamber. Based on Embodiment 3, this method further includes the following steps: Step 7, System Monitoring and Maintenance: Monitor pH, turbidity, and conductivity parameters daily and calibrate the detector; add bactericide twice a month (in summer) or once a month (in other seasons); check the corrosion of the plate fins every six months; and chemically clean the plate heat exchanger every two years.

[0042] Verification of the effect of Example 4: After the system was running for 12 months using the method of this example, there were no new corrosion spots in the furnace chamber, the water was clear, the equipment was running normally, and no unplanned shutdowns caused by the cooling water system occurred.

Claims

1. A method for stabilizing water quality in an EB furnace chamber circulating cooling water system, characterized in that, The method specifically includes the following steps: Step 1, Chemical Cleaning: Add a multi-functional cleaning agent to the circulating cooling water system of the EB furnace. After adding the multi-functional cleaning agent, keep the system running for 24 to 48 hours. During this period, monitor the pH value and water color changes. When the pH value is stable and the water color no longer darkens, it indicates that the reaction is over and the cleaning is complete. Step 2, Water Replacement and Replenishment: The waste liquid from chemical cleaning is discharged, and the residual cleaning waste liquid in the equipment is fully neutralized with a slightly alkaline aqueous solution. Then, the system is subjected to a large-scale water replacement process to flush out the residue in the system, and then water is replenished. Step 3, System pre-filming treatment: Add a pre-filming agent to the system and control the pH of the circulating water at 9.0–10.0, and continue circulating for 36–48 hours; after the pre-filming treatment is completed, perform water replacement again until the pH value stabilizes at 8.5–9.

0. Step 4, corrosion and scale inhibition treatment: Add corrosion and scale inhibitors to the system; after the system is running normally, continue to add corrosion and scale inhibitors daily to control the pH value of the circulating water between 8.0 and 9.5; periodically suspend carbon steel and stainless steel hanging plates to monitor corrosion. Step 5, Microbial Control: Add non-oxidizing bactericide and algaecide 1-2 times per month; after addition, run for 6-12 hours to sterilize, then discharge sewage and replenish with softened water to the normal water level.

2. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step one, the dosage of the multifunctional cleaning agent is calculated based on the water volume of the EB furnace circulating cooling water system, and the dosage concentration is 5-10 g / L.

3. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step two, the pH value of the slightly alkaline aqueous solution is 7.5 to 8.

5.

4. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step two, when replenishing water, tap water and softened water are mixed at a volume ratio of (1.5 to 2.5):

1.

5. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step three, the amount of pre-filming agent added is 0.3 to 0.8 wt% of the water volume of the EB furnace circulating cooling water system.

6. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step four, the initial dosage of the scale inhibitor is 0.15 to 0.25 wt% of the water volume in the EB furnace circulating cooling water system.

7. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step five, the non-oxidizing bactericide and algaecide is composed of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, with a molar ratio of 3:

1.

8. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, In step five, the dosage of the non-oxidizing bactericide and algaecide is 0.05 to 0.1 wt% of the water volume in the EB furnace circulating cooling water system.

9. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, It also includes step six, system monitoring and maintenance: regularly testing water quality parameters such as pH, turbidity, and conductivity; inspecting or cleaning the plate heat exchanger every 1 to 2 years; and regularly calibrating the pH meter to ensure accurate measurements.

10. The water quality stabilization treatment method for EB furnace circulating cooling as described in claim 1, characterized in that, If the system is heavily contaminated, the circulating cooling water system of the EB furnace should be replaced several times before chemical cleaning to remove as much rust and other corrosion products, trace amounts of scale and biological slime that have accumulated in the cooling system over a long period of time, so that the water quality can be initially normalized.

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