A method for cathodic protection of water coolers

Abstract

The application discloses a water cooler cathodic protection corrosion prevention method, comprising the following steps: S1, cathode and anode material selection; S2, base material pretreatment and connection; S3, system deployment; S4, adaptive current regulation; S5, operation monitoring and fault handling. The water cooler cathodic protection corrosion prevention method, through targeted anode and cathode material selection and standardized base material connection process, reduces the loop contact resistance, solves the problem of insufficient stability of the traditional cathodic protection system; through the adaptive current intelligent regulation algorithm, the limitations of fixed current or manual adjustment cannot adapt to the dynamic changes of the working conditions are broken through, the corrosion intensification caused by insufficient protection and the base material hydrogen embrittlement risk caused by over-protection are effectively avoided, and the equipment is ensured to be in the optimal corrosion prevention state at all times, thereby solving the problems of easy peeling of the traditional coating corrosion prevention and high repair cost, and the durable corrosion prevention effect can be achieved without relying on chemical corrosion inhibitors.

Description

Technical Field

[0001] This invention relates to the field of water cooler corrosion protection technology, specifically a cathodic protection corrosion protection method for water coolers. Background Technology

[0002] Water coolers are indispensable heat exchange equipment in industrial production, widely used to cool various process media. Their metal casings are in long-term contact with cooling media such as water, seawater, and industrial circulating water. Dissolved oxygen, chloride ions, and microorganisms in these media can easily trigger electrochemical corrosion of the metal, leading to thinning of the equipment walls and leaks. This not only reduces the service life of the water cooler and increases maintenance costs but can also cause process media leaks, production shutdowns, and serious economic losses and safety accidents. Currently, existing anti-corrosion methods for water coolers mainly include coating and adding corrosion inhibitors. Coating anti-corrosion involves applying an anti-corrosion coating to the metal surface to isolate corrosive media, but mechanical vibration and media scouring under industrial conditions can easily cause the coating to peel off, and coating repair requires downtime, resulting in high maintenance costs. Adding corrosion inhibitors involves adding chemical corrosion inhibitors to the cooling media to inhibit corrosion, but their inhibitory effect gradually diminishes over time, and chemical corrosion inhibitors can easily cause water pollution, failing to meet environmental protection requirements. Cathodic protection technology, as an electrochemical corrosion prevention method, has been gradually applied to the corrosion prevention of metal equipment due to its long-lasting corrosion prevention effect and lack of secondary pollution. However, the existing cathodic protection technology for water coolers still has obvious shortcomings: traditional cathodic protection mostly adopts fixed current or manual fine-tuning, which cannot adapt to dynamic changes in operating conditions such as temperature, salinity, and flow rate of the cooling medium in real time. This can easily lead to problems such as insufficient protection (corrosion is not effectively inhibited) or overprotection (hydrogen embrittlement occurs, resulting in a decrease in the strength of the metal substrate). Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a cathodic protection and corrosion prevention method for water coolers, which solves the problems mentioned in the background section.

[0004] To achieve the above objectives, the present invention provides a method for cathodic protection and corrosion prevention of a water cooler, comprising the following steps: S1. Selection of cathode and anode materials: Using the metal shell of the water cooler as the cathode body, the sacrificial anode or the impressed current anode is selected as the anode material according to the working environment of the water cooler and the properties of the cooling medium. S2. Substrate pretreatment and connection: The anode connection part of the metal shell of the water cooler is pretreated, and the anode material is fixed to the cathode body by welding or bolting to construct the basic circuit of cathodic protection. S3. Adjustment System Deployment: In the working environment of the water cooler, a sensor for acquiring operating parameters and a reference electrode are installed, and an intelligent adjustment device consisting of an acquisition module, an algorithm calculation module and a potentiostat is electrically connected to the basic circuit of the cathodic protection. S4, Adaptive Current Regulation: The temperature, salinity, pH value, and flow rate of the cooling medium are collected in real time by sensors. The optimal protection current is calculated using an adaptive cathodic protection current intelligent adjustment algorithm. The current is output by a potentiostat and the potential closed-loop correction is achieved through a reference electrode. S5. Operation Monitoring and Fault Handling: Regularly monitor the cathodic protection potential, current, and operating parameters. When abnormal parameters are detected, troubleshoot the fault and take corresponding repair measures.

[0005] Furthermore, in step S1, when the cathode body is a water cooler metal shell made of carbon steel, stainless steel or copper alloy, when the sacrificial anode method is used, the anode material is selected from zinc-aluminum-cadmium alloy, magnesium-aluminum-zinc-manganese alloy or aluminum-zinc-indium alloy; when the impressed current method is used, the anode material is selected from titanium-based ruthenium-iridium coated anode, platinum-niobium alloy anode or high-purity graphite anode.

[0006] Furthermore, in step S2, the substrate pretreatment includes removing oil, rust, and scale from the connection area by sandblasting and grinding, so that the surface cleanliness of the substrate reaches Sa2.5 level and the roughness is 50~80μm; when welding, argon arc welding or manual electric arc welding is used; when bolting, a conductive gasket is added between the bolt and the substrate, and anti-loosening adhesive and conductive paste are applied to the threads.

[0007] Furthermore, in step S4, the adaptive cathodic protection current intelligent adjustment algorithm includes three stages: basic protection current calculation, operating condition parameter correction, and potential closed-loop correction. The basic protection current calculation formula is:

[0008] in, Basic protection current; The effective corrosion protection area of ​​the metal casing of the water cooler; The critical protection current density for the water cooler substrate; The current efficiency of the cathodic protection system, expressed as a percentage.

[0009] Furthermore, the operating condition parameter correction is achieved by introducing a temperature correction coefficient. Salinity correction factor pH correction factor Flow rate correction factor The corrected protection current is obtained. The calculation formula is:

[0010] in, , Temperature of the cooling medium; , This represents the mass fraction of NaCl in the cooling medium. pH∈6~9; , This refers to the flow rate of the cooling medium.

[0011] Furthermore, the potential closed-loop correction is based on the actual protection potential acquired by the reference electrode. With the theoretical optimal protection potential To address the deviation, a potential correction factor is introduced. To obtain the real-time optimal protection current The calculation formula is:

[0012] .

[0013] Furthermore, the theoretical optimal protection potential of the carbon steel substrate. The voltage range is -0.85 to -1.20V.

[0014] Furthermore, stainless steel substrate The voltage range is from -0.75 to -1.00V.

[0015] Furthermore, the monitoring cycle for the operating parameters and cathodic protection parameters is 7 to 30 days, and the monitoring frequency is adjusted according to the severity of the working environment of the water cooler; abnormal parameters include protection potential deviating from the theoretical optimal range by more than ±0.05V, current fluctuation exceeding 10%, and sudden change in salinity of the cooling medium exceeding 0.5%.

[0016] This invention provides a cathodic protection and corrosion prevention method for water coolers, which has the following beneficial effects: 1. This cathodic protection corrosion prevention method for water coolers reduces circuit contact resistance and solves the problem of insufficient stability in traditional cathodic protection systems by selecting appropriate anode and cathode materials and standardizing substrate connection processes. Through an adaptive current intelligent adjustment algorithm, it overcomes the limitations of fixed current or manual adjustment in adapting to dynamic changes in operating conditions, effectively avoiding corrosion aggravation caused by insufficient protection and the risk of hydrogen embrittlement of the substrate caused by overprotection. This ensures that the equipment is always in optimal corrosion protection condition, thus eliminating the problems of easy peeling and high repair costs associated with traditional coating corrosion prevention. It achieves long-lasting corrosion protection without relying on chemical corrosion inhibitors, completely eliminating the risks of inhibitor decay and water pollution. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the steps of a cathodic protection and corrosion prevention method for a water cooler according to the present invention. Detailed Implementation

[0018] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0019] like Figure 1 As shown, this invention provides a technical solution: a cathodic protection and corrosion prevention method for water coolers, comprising five major steps: selection of anode and cathode materials, substrate pretreatment and connection, deployment of an intelligent adjustment system, adaptive current adjustment, operation monitoring and fault handling. Simultaneously, based on an adaptive cathodic protection current intelligent adjustment algorithm using multiple linear regression and potential closed-loop correction, it achieves dynamic and accurate calculation and output of the protection current. The specific technical solution is as follows: Selection of cathode and anode materials: The metal shell of the water cooler is used as the cathode body. The cathode body material is selected from carbon steel, stainless steel or copper alloy according to the industrial conditions. The anode material is either a sacrificial anode or an impressed current anode. The selection is determined based on the working environment of the water cooler and the properties of the cooling medium. Sacrificial anode method: Suitable for water coolers with good conductivity of cooling medium and small anti-corrosion area. The anode material is selected from zinc-aluminum-cadmium alloy (suitable for seawater medium), magnesium-aluminum-zinc-manganese alloy (suitable for freshwater medium), and aluminum-zinc-indium alloy (suitable for high salinity circulating water medium). The mass and size of the anode material are determined based on the effective anti-corrosion area of ​​the water cooler. Impressed current method: Suitable for water coolers with poor conductivity of cooling medium and large corrosion protection area. The anode material is selected from titanium-based ruthenium-iridium coated anode, platinum-niobium alloy anode or high-purity graphite anode. The number of anode materials is arranged according to the current output requirements. Substrate pretreatment and bonding: The anode connection area of ​​the water cooler's metal shell is pretreated to remove surface oil, rust, scale, and other impurities. Sandblasting and grinding are used to achieve a surface cleanliness of Sa2.5 and a roughness of 50-80 μm, enhancing the conductivity and bonding strength of the connection area. The anode material is fixed to the cathode body using welding or bolting. For welding, a welding wire matching the substrate is selected, and either argon arc welding or manual arc welding is employed. Welding current, voltage, and welding speed are strictly controlled to avoid defects such as incomplete welds, porosity, and slag inclusions. For bolted connections, a copper conductive gasket is added between the bolt and the substrate, and anti-loosening adhesive and conductive paste are applied to the threads to prevent loosening and increased contact resistance. After the anode and cathode body are connected, a basic cathodic protection circuit is constructed, ensuring a circuit resistance ≤0.5Ω. Adjustment system deployment: The control system consists of a condition parameter acquisition module, an algorithm calculation module, an execution control module, and a reference electrode. Operating Parameter Acquisition Module: Equipped with temperature sensors, salinity sensors, pH sensors, and flow rate sensors to collect the temperature of the cooling medium in real time. NaCl mass fraction pH value, flow rate The sampling frequency is 1~5 minutes / time; Algorithm calculation module: It adopts an embedded microcontroller or industrial computer, with a built-in adaptive cathodic protection current intelligent adjustment algorithm to complete parameter reception, data calculation and instruction output; The adjustment module uses a high-precision potentiometer, which is electrically connected to the algorithm calculation module and outputs the real-time optimal protection current according to the algorithm instructions. Reference electrode: A saturated calomel electrode (SCE) or a silver or silver chloride electrode is selected and placed close to the metal casing of the water cooler to collect the actual cathodic protection potential in real time. This provides data support for potential closed-loop correction; Each module is electrically connected by high-temperature and corrosion-resistant cables, which are protected by conduits to avoid damage from external forces or corrosion from the medium. Adaptive current regulation: Adaptive current regulation achieves dynamic and precise adjustment of the protection current through three stages: basic protection current calculation, operating condition parameter correction, and potential closed-loop correction. This ensures that the metal shell of the water cooler is always within the theoretically optimal protection potential range. The specific calculation process is as follows: I. Calculation of basic protection current: Calculate the basic protection current based on the effective corrosion protection area of ​​the metal shell of the water cooler and the critical protection current density of the substrate. The formula is:

[0020] In the formula, The effective corrosion protection area of ​​the metal casing of the water cooler is determined by combining equipment drawings with actual measurements. The critical protection current density (mA / m²) of the substrate, carbon steel substrate mA / m², stainless steel substrate mA / m²; For the current efficiency (%) of the cathodic protection system, the welded connection Bolted connection ; II. Correction of operating parameters: The temperature, salinity, pH value, and flow rate of the cooling medium directly affect the electrochemical corrosion rate of the metal. Therefore, a corresponding correction factor is introduced to adjust the basic protection current according to the operating conditions, resulting in the corrected protection current. The formula is:

[0021] in, , Temperature of the cooling medium (°C); , The mass fraction (%) of NaCl in the cooling medium; pH∈6~9; , The flow rate of the cooling medium is (m / s). III. Potential Closed-Loop Correction: Actual protection potential acquired based on reference electrode Theoretical optimal protection potential of the substrate To address the deviation, a potential correction factor is introduced. The corrected protection current is then subjected to closed-loop correction to obtain the real-time optimal protection current. The formula is:

[0022]

[0023] Among them, the theoretical optimal protection potential of carbon steel substrate -0.85 to -1.20V (relative to a saturated calomel electrode); stainless steel substrate -0.75 to -1.00 V (relative to a saturated calomel electrode); when This indicates insufficient protection. The system increases the output current; when At that time, the protection was explained. The system reduces the output current; The potentiostat calculates based on the algorithm. It executes current output to achieve real-time adaptive adjustment of protection current; Operation monitoring and troubleshooting: Routine monitoring: Regularly collect cathodic protection potential. Real-time protection current The monitoring period for the operating parameters of the cooling medium is 7 to 30 days. For severe operating conditions (such as high salinity and high temperature), the period is shortened to 7 days, and for normal operating conditions, it is 30 days. At the same time, the monitoring data is recorded and an equipment corrosion prevention operation file is established. Anomaly detection: The following conditions are considered as parameter anomalies: ① The protection potential deviates from the theoretical optimal range by more than ±0.05V; ② The protection current fluctuates by more than 10% for more than 1 hour; ③ The salinity and pH value of the cooling medium change by more than 0.5% and 0.5 pH units, respectively. For each type of fault identified due to abnormal parameters, corresponding remedial measures were taken, as follows: Anode material corrosion and damage: Replace the anode material, reconnect and recalibrate; Loose connections: Tighten bolts or weld repairs, reapply conductive paste, and test circuit resistance until it meets the requirements; Sensor failure: Replace the faulty sensor and recalibrate the data acquisition accuracy; Abnormal cooling medium composition: Add water quality conditioner to the cooling medium to adjust the salinity and pH value to the normal range; Potentiostat malfunction: Repair or replace the potentiostat and re-match it with the algorithm module; Example: Used for cathodic protection and corrosion prevention of carbon steel water coolers in thermal power plants; Cathode body: Carbon steel metal shell of water cooler; Anode material: Titanium-based ruthenium-iridium coated anodes are selected using the impressed current method, with a total of 4 anodes, and the effective output current of a single anode is 2A; The anode connection area of ​​the metal shell of the water cooler is pretreated by sandblasting and grinding to remove oil and rust, so that the surface cleanliness reaches Sa2.5 level and the roughness is 60μm. The titanium-based ruthenium-iridium coated anode is welded to the pretreated area by argon arc welding with a welding current of 120~150A and a voltage of 20~25V. After welding, the resistance of the cathodic protection base circuit is tested and the resistance is measured to be 0.3Ω, which meets the requirement of ≤0.5Ω. One set of temperature sensor, salinity sensor, pH sensor, and flow rate sensor are installed at the inlet and outlet of the cooling medium, respectively, with a data acquisition frequency of 3 minutes / time. The reference electrode is a saturated calomel electrode (SCE), installed close to the metal shell of the water cooler. The algorithm calculation module uses an embedded microcontroller with a built-in adaptive cathodic protection current intelligent adjustment algorithm. The execution adjustment module uses a potentiostat with an accuracy of ±0.01A, which is electrically connected to the algorithm calculation module, anode material, and cathode body. All cables are protected by PTFE conduits to avoid corrosion from circulating water and damage from external forces. Basic protection current calculation: carbon steel substrate mA / m², welded connection Effective corrosion protection area Substituting m² into the formula, we get: Operating Parameter Correction: Real-time operating parameters of the collected cooling medium are as follows , , , For m / s, calculate the correction factors respectively: , , , Substituting into the formula, we obtain the corrected protection current: ; Theoretical optimal protection potential for carbon steel substrate V (relative to SCE), the actual protection potential acquired by the reference electrode. V, calculate the potential correction factor:

[0024] Real-time optimal protection current: The potentiostat outputs a protection current of 0.678A based on the calculation results, and the actual protection potential collected by the reference electrode after adjustment is then used. It enters the theoretically optimal range of -0.85 to -1.20V; In this embodiment, a 7-day monitoring cycle was used. After 5 months of operation, the protection potential was detected. The voltage (V) deviated from the theoretical optimal range, indicating insufficient protection. Upon inspection, a slight loosening was found at the weld between the anode and cathode, increasing the contact resistance to 1.2Ω. The weld was repaired, re-ground, and coated with conductive paste. After repair, the circuit resistance was measured at 0.28Ω, and the intelligent adjustment system was recalibrated. Following the repair, the system calculated the real-time optimal protection current. A, Actual protection potential V, restored to the optimal range; After adopting the anti-corrosion method of this invention, the water cooler showed no obvious corrosion after one year of operation. Compared with the same type of water cooler using traditional coating anti-corrosion, the corrosion rate was reduced by more than 95%, and the expected service life could be extended from the original 3 years to more than 7.5 years, an extension of 150%. Moreover, there is no need to replace the coating or add corrosion inhibitors, and the annual maintenance cost is reduced by 80%. Based on the above description, this invention reduces circuit contact resistance and solves the problem of insufficient stability in traditional cathodic protection systems by selecting appropriate anode and cathode materials and standardizing substrate connection processes. Furthermore, by employing an adaptive current intelligent adjustment algorithm, it overcomes the limitations of fixed current or manual adjustment in adapting to dynamic changes in operating conditions, effectively avoiding the risk of increased corrosion due to insufficient protection and hydrogen embrittlement of the substrate caused by overprotection. This ensures that the equipment is always in optimal corrosion protection condition, thereby eliminating the problems of easy peeling and high repair costs associated with traditional coating corrosion protection. It achieves long-lasting corrosion protection without relying on chemical corrosion inhibitors, completely eliminating the risks of inhibitor decay and water pollution.

[0025] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for cathodic protection and corrosion prevention of a water cooler, characterized in that: Includes the following steps: S1. Selection of cathode and anode materials: Using the metal shell of the water cooler as the cathode body, the sacrificial anode or the impressed current anode is selected as the anode material according to the working environment of the water cooler and the properties of the cooling medium. S2. Substrate pretreatment and connection: The anode connection part of the metal shell of the water cooler is pretreated, and the anode material is fixed to the cathode body by welding or bolting to construct the basic circuit of cathodic protection. S3. Adjustment System Deployment: In the working environment of the water cooler, a sensor for acquiring operating parameters and a reference electrode are installed, and an intelligent adjustment device consisting of an acquisition module, an algorithm calculation module and a potentiostat is electrically connected to the basic circuit of the cathodic protection. S4, Adaptive Current Regulation: The temperature, salinity, pH value, and flow rate of the cooling medium are collected in real time by sensors. The optimal protection current is calculated using an adaptive cathodic protection current intelligent adjustment algorithm. The current is output by a potentiostat and the potential closed-loop correction is achieved through a reference electrode. S5. Operation Monitoring and Fault Handling: Regularly monitor the cathodic protection potential, current, and operating parameters. When abnormal parameters are detected, troubleshoot the fault and take corresponding repair measures.

2. The cathodic protection and corrosion prevention method for a water cooler according to claim 1, characterized in that: In step S1, when the cathode body is a water cooler metal shell made of carbon steel, stainless steel or copper alloy, when the sacrificial anode method is used, the anode material is selected from zinc-aluminum-cadmium alloy, magnesium-aluminum-zinc-manganese alloy or aluminum-zinc-indium alloy; when the impressed current method is used, the anode material is selected from titanium-based ruthenium-iridium coated anode, platinum-niobium alloy anode or high-purity graphite anode.

3. The cathodic protection and corrosion prevention method for a water cooler according to claim 1, characterized in that: In step S2, the substrate pretreatment includes removing oil, rust, and scale from the connection area by sandblasting and grinding, so that the surface cleanliness of the substrate reaches Sa2.5 level and the roughness is 50~80μm; when welding, argon arc welding or manual electric arc welding is used; when bolting, a conductive gasket is added between the bolt and the substrate, and anti-loosening adhesive and conductive paste are applied to the threads.

4. The cathodic protection and corrosion prevention method for a water cooler according to claim 1, characterized in that: In step S4, the adaptive cathodic protection current intelligent adjustment algorithm includes three stages: basic protection current calculation, operating condition parameter correction, and potential closed-loop correction. The basic protection current calculation formula is as follows: in, Basic protection current; The effective corrosion protection area of ​​the metal casing of the water cooler; The critical protection current density for the water cooler substrate; The current efficiency of the cathodic protection system, expressed as a percentage.

5. The cathodic protection and corrosion prevention method for a water cooler according to claim 4, characterized in that: The operating condition parameters are corrected by introducing a temperature correction coefficient. Salinity correction factor pH correction factor Flow rate correction factor The corrected protection current is obtained. The calculation formula is: in, , Temperature of the cooling medium; , This represents the mass fraction of NaCl in the cooling medium. pH∈6~9; , This refers to the flow rate of the cooling medium.

6. The cathodic protection and corrosion prevention method for a water cooler according to claim 4, characterized in that: The potential closed-loop correction is based on the actual protection potential collected by the reference electrode. With the theoretical optimal protection potential To address the deviation, a potential correction factor is introduced. To obtain the real-time optimal protection current The calculation formula is: 。 7. The cathodic protection and corrosion prevention method for a water cooler according to claim 6, characterized in that: Theoretical optimal protection potential of carbon steel substrate The voltage range is -0.85 to -1.20V.

8. The cathodic protection and corrosion prevention method for a water cooler according to claim 6, characterized in that: Stainless steel substrate The voltage range is from -0.75 to -1.00V.

9. The cathodic protection and corrosion prevention method for a water cooler according to claim 1, characterized in that: In step S5, the monitoring cycle for the operating parameters and cathodic protection parameters is 7 to 30 days, and the monitoring frequency is adjusted according to the severity of the working environment of the water cooler. Abnormal parameters include protection potential deviating from the theoretical optimal range by more than ±0.05V, current fluctuation exceeding 10%, and sudden change in salinity of the cooling medium exceeding 0.5%.

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