Converter valve cooling water system corrosion and scaling combined simulation test method and device

Abstract

The invention relates to a converter valve cooling water system corrosion and scaling combined simulation test method and device. The method comprises the following steps: building a closed circulation loop; raising the water temperature to 24-26 DEG C by using a tubular heater; adjusting the concentration and conductivity of scaling ions in a closed circulation loop to realize an acid-base environment for accelerated simulation of the scaling process, and adjusting the concentration of aluminum ions in initial circulating water to 2.5 mg.L <-1 > when the conductivity is adjusted to be lower than 0.5 mu S.cm <-1 >; applying a high-voltage direct-current voltage, and establishing an electric field through a voltage-sharing electrode; continuously operating for at least 336 hours, and regularly detecting water quality parameters through the sampling measurement pool; and after the test is finished, taking out the voltage-sharing electrode, analyzing the scaling morphology and components on the surface of the voltage-sharing electrode, and evaluating the scaling characteristics under different water quality conditions. Compared with the prior art, the device has the advantages of accurately simulating the multi-field coupling operation environment of the water cooling system in the flexible direct current converter valve, realizing accurate analysis of the scaling characteristics of the converter valve and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-voltage direct current transmission systems, in particular to a method and device for simulating corrosion and fouling of a converter valve cooling water system. BACKGROUND

[0002] A converter valve is one of the core devices in a high-voltage direct current transmission system (HVDC), and plays a key role in converting between alternating current (AC) and direct current (DC). A valve module, as a basic electrical unit of the converter valve, is composed of a plurality of thyristors. Generally, a large amount of heat is generated by the thyristor conduction current (3000-5000 A) during actual operation, and a special internal cooling water system must be provided to cool the thyristors so that the operating junction temperature of the thyristors is maintained within a normal range. The internal cooling water system of the converter valve, as one of the most important auxiliary systems of the converter valve, plays a role in ensuring the safe operation of the device.

[0003] The core component of the internal cooling water system of the converter valve is an aluminum radiator, which directly contacts the thyristor and conducts heat to the cooling water circuit. Maintaining the high efficiency and stable working state of the radiator is of great significance to ensuring the normal operation of the internal thermal management system of the converter valve, improving the stability of the system, and prolonging the service life of the electrical equipment. However, the high-voltage environment generated during the actual operation of the converter valve acts on the radiator, and a leakage current is generated through the internal cooling water circuit. This leakage current can easily cause metal corrosion and fouling.

[0004] The hazards of radiator leakage current corrosion are as follows: 1. The leakage current can directly cause electrochemical corrosion of the metal and rubber seal ring (such as corrosion of the stainless steel ring in the main water circuit and pitting corrosion on the surface of the radiator, and aging of the rubber seal ring, which leads to failure of the rubber seal ring), thereby causing a water leakage accident and leading to system shutdown.

[0005] 2. The leakage current corrosion causes metal corrosion ions to enter the internal cooling water system, which is the cause of the fouling of the voltage equalizing electrode. The shedding of the rod-shaped fouling on the surface of the voltage equalizing electrode can cause waterway blockage, leading to poor heat dissipation of the electrical components and causing damage to them, and even triggering the valve temperature protection to cause the converter valve to shut down.

[0006] 3. The fouling adsorbed on the surface of the electrode is in a high resistance state, which causes the voltage equalizing electrode to lose its equalizing ability, and the uneven electric field in the water circuit and on the surface of the electrode will further exacerbate the corrosion of the radiator and the rubber seal ring, which can easily cause a water leakage accident and lead to system shutdown.

[0007] The existing Chinese patent application CN111948128A discloses a converter valve internal cooling water system radiator corrosion test platform, which comprises a cooling water driving and detection module, a cooling and heat dissipation module, a power supply voltage division module, and pipelines and lines for connecting the modules. The cooling water driving and detection module is used to supply circulating water to the cooling and heat dissipation module and can detect and control the water quality parameters of the circulating water. The cooling water driving and detection module is also provided with a deionization branch. The cooling and heat dissipation module comprises n aluminum radiators, a single transparent simulation radiator, a plurality of voltage equalizing electrodes, and a plurality of water pressure gauges connected by pipelines, and n is a positive integer greater than 1. The n aluminum radiators and the single transparent simulation radiator are connected in parallel. A voltage equalizing electrode is installed on the inlet and outlet water branch flow of the two outermost aluminum radiators. The power supply voltage division module comprises a resistor, a high-voltage test power supply, and an ammeter. The voltage division circuit is composed of a plurality of megohm resistors connected in series, and the two ends are connected to the high-voltage test power supply and the ground, respectively. Different nodes on the voltage division circuit are connected to the n aluminum radiators and the voltage equalizing electrodes through wires, and an ammeter is provided on each connection line. By studying the corrosion morphology and corrosion efficiency of the radiator under different working conditions, the corrosion mechanism of the radiator is revealed, and the corrosion trend of the radiator under certain working conditions is predicted. However, this test platform only considers the corrosion problem and cannot simulate the real situation of the converter valve internal cooling water system radiator. There are also deficiencies in the test efficiency.

[0008] The corrosion and fouling problems of the converter valve cooling water system radiator directly threaten the safe and stable operation of the power grid, and the existing test methods cannot meet the needs of precise simulation of real working conditions, fast experimental speed, and technical optimization. SUMMARY

[0009] The purpose of the present application is to overcome the shortcomings of the prior art and provide a converter valve cooling water system corrosion and fouling combined simulation test method and device.

[0010] The purpose of the present application can be achieved by the following technical solutions: A converter valve cooling water system corrosion and fouling combined simulation test method, comprising the following steps: Building a closed circulation loop and filling it with deionized water; Using a tubular heater to raise the water temperature to 24-26℃; Adjusting the concentration of fouling ions and the conductivity of the closed circulation loop to achieve an acid-base environment for accelerating the simulation of the fouling process, wherein the conductivity is reduced to 0.5 μS·cm -1 In the following, the initial circulating water is adjusted to an aluminum ion concentration of 2.5 mg·L -1 ; Applying high-voltage direct current to the radiator assembly through a bridge-type resistor voltage division circuit, and establishing an electric field through the voltage equalizing electrodes to induce a leakage current; The water quality parameters are periodically detected by sampling and measuring the pool during the continuous operation of at least 336 hours; After the test, the equalizing electrode is taken out, the surface scaling morphology and composition of the equalizing electrode are analyzed, and the scaling characteristics under different water quality conditions are evaluated.

[0011] Further, during the continuous operation, the leakage current is monitored by an ammeter.

[0012] Further, the closed loop is connected by the radiator assembly, the sampling and measuring pool, the water pump, the liquid flow meter, and the tubular heater.

[0013] Further, the radiator assembly, the sampling and measuring pool, the water pump, the liquid flow meter, and the tubular heater are connected by polyvinyl chloride or fluorinated ethylene propylene copolymer pipe fittings.

[0014] Further, the high-voltage direct-current voltage is generated by a ±40kV / 20mA high-voltage direct-current power supply.

[0015] Further, the radiator assembly includes a plurality of aluminum radiators arranged in parallel, the material of the aluminum radiators is 6063 aluminum alloy, and the aluminum radiators are connected to the branch water pipes through FEP hard nozzles.

[0016] Further, the aluminum ion concentration in the initial circulating water is adjusted by an aluminum ion-containing solution, and the aluminum ion-containing solution includes an AlCl3 solution, a NaAl(OH)4 solution, or an aluminum hydroxide colloid.

[0017] The application also provides a test device for implementing the combined simulation test method of the converter valve cooling water system corrosion and scaling as described above, comprising: The radiator assembly includes a plurality of aluminum radiators arranged in parallel, each aluminum radiator is connected in series with a water-cooled resistor and then connected to the branch water circuit to form a parallel cooling structure simulating the internal cooling water system of the converter valve; The circulating loop assembly includes a sampling and measuring pool, a water pump, a liquid flow meter, and a tubular heater, and the radiator assembly, the sampling and measuring pool, the water pump, the liquid flow meter, and the tubular heater are connected to form a closed circulating loop, and the sampling and measuring pool is provided with a water quality parameter measuring assembly for online or offline monitoring of the water quality parameters of the circulating cooling water; The direct-current high-voltage power supply module includes a high-voltage direct-current power supply, a bridge-type resistance voltage dividing circuit, and a platinum needle-shaped equalizing electrode, the bridge-type resistance voltage dividing circuit divides the output voltage of the high-voltage direct-current power supply to both ends of the radiator assembly, and applies an electric field through the platinum needle-shaped equalizing electrode to simulate the leakage current path in actual operation; The water quality control module is used to adjust the scaling ion concentration and conductivity of the closed circulating loop to accelerate the simulation of the scaling process under different acid-base environments.

[0018] Further, the water quality regulating module comprises: A deionization resin tank connected to the closed circulation loop through a bypass for reducing the conductivity of the circulating water to 0.5 μS·cm -1 The following; A chemical reagent injection unit for adding an aluminum ion-containing solution to the closed circulation loop to achieve an initial aluminum ion concentration of 2.5 mg·L -1 , and to realize accelerated simulation of the fouling process.

[0019] Further, the water quality parameter measuring assembly comprises a pH meter, a conductivity meter and a dissolved oxygen meter.

[0020] Compared with the prior art, the present application has the following beneficial effects: 1. The present application can realize accelerated simulation of fouling and corrosion, and the parameters are controllable, and the real working condition simulation is realized, and the simulation experiment platform can independently control the pH, conductivity, ion concentration, temperature, flow rate and electric field strength, so as to accurately simulate the multi-field coupling operating environment (electric field-chemistry-flow-heat) of the water cooling system inside the HVDC valve.

[0021] 2. The present application can quantitatively analyze the electrode surface fouling behavior, and by regulating the water quality, the fouling characteristics (fouling distribution, fouling rate) of the equalizing electrode fouling under different water quality parameters can be obtained, and the chemical components of the fouling can be obtained through laboratory characterization means.

[0022] 3. The present application accelerates the electrochemical reaction rate and the deposition rate by adjusting the fouling ion concentration, so as to reproduce the long-term running fouling phenomenon in a short time.

[0023] 4. The present application is provided with a tubular heater for heating the water temperature, so that the water temperature during the test is consistent with the actual working temperature, and the multi-field coupling operating environment of the water cooling system inside the HVDC valve can be more accurately simulated. BRIEF DESCRIPTION OF DRAWINGS

[0024] Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included solely for purposes of illustrating the preferred embodiments and are not to be construed as a limitation of the present application. It should be readily understood that the drawings depicted are only some embodiments of the present application and that any other drawings similarly drawn can be derived from these drawings without using inventive faculty. Moreover, the same reference numerals in the drawings denote the same elements or components.

[0025] Figure 1 FIG. 1 is a structural schematic diagram of an embodiment of the experimental platform of the present application; Figure 2This is a schematic diagram of the method flow according to the present invention; Figure 3 This is a schematic diagram of the surface morphology of the electrode after drying in the weakly acidic environment scaling test of the present invention. In the figure, 1-water-cooled resistor, 2-heat sink assembly, 3-ammeter, 4, 5, 6, 7-equalizing electrodes, 8-high voltage DC power supply, 9-sampling and measuring cell, 10-water pump, 11-liquid flow meter, 12-deionized resin tank, 13-tubular heater. Detailed Implementation

[0026] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0027] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0028] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0029] Example 1 like Figure 1 As shown, this embodiment provides a simulation test device for corrosion and scaling in a converter valve cooling water system, comprising: The radiator assembly 2 includes multiple aluminum radiators connected in parallel. Each aluminum radiator is connected in series with a water-cooled resistor 1 and then connected to a branch water circuit to form a parallel cooling structure that simulates the internal cooling water system of the converter valve. A closed loop is formed by connecting the radiator assembly 2, the sampling and measurement cell 9, the water pump 10, the liquid flow meter 11, and the tubular heater 13. The sampling and measurement cell 9 is equipped with a pH meter, conductivity meter, and dissolved oxygen meter to monitor the water quality parameters of the circulating cooling water online or offline. A DC high-voltage power supply module adopts a bridge-type resistance voltage dividing circuit to distribute the output voltage of a high-voltage DC power supply to both ends of a radiator assembly 2, and applies an electric field through platinum needle-shaped voltage equalizing electrodes 4, 5, 6, 7 to simulate the leakage current path in actual operation. A water quality control module adjusts the concentration of scale-forming ions by adding an aluminum ion-containing solution to the closed loop, and adjusts the conductivity in combination with a deionization resin tank 12 to achieve accelerated simulation of the scaling process under different acid-base environments.

[0030] In a preferred embodiment, the closed loop water system is connected by polyvinyl chloride or fluorinated ethylene propylene copolymer pipe fittings.

[0031] In a preferred embodiment, the aluminum radiator material is 6063 aluminum alloy, and the number is 6 pieces. Each aluminum radiator is connected to a soft FEP branch water pipe through an FEP hard nozzle.

[0032] In a preferred embodiment, the voltage equalizing electrodes 4, 5, 6, 7 are two pairs of platinum needle electrodes installed at both ends of the manifold, and are electrically connected to the corresponding position of the aluminum radiator, so that the potential is consistent with the adjacent aluminum radiator.

[0033] In a preferred embodiment, a plurality of ammeters 3 are provided to monitor the leakage current flowing into / out of the radiator and the voltage equalizing electrodes 4, 5, 6, 7 in real time.

[0034] In a preferred embodiment, the water quality control module includes: A deionization resin tank 12 is connected to the closed loop water system through a bypass for reducing the conductivity of the circulating water to 0.5 μS·cm -1 The following; A chemical reagent injection unit is used to add AlCl3 solution, NaAl(OH)4 solution or aluminum hydroxide colloid to the closed loop water system to achieve an initial aluminum ion concentration of 2.5 mg·L -1 , to achieve accelerated simulation of the scaling process.

[0035] In a preferred embodiment, the sampling and measuring pool 9 is a transparent organic glass container with a sealing cover on the top, integrated with pH electrodes, conductivity electrodes and dissolved oxygen electrodes to support continuous dynamic monitoring of water quality changes.

[0036] The water cooling system simulation test device in the converter valve provided by the embodiment comprises a radiator assembly 2, a sampling and measuring pool 9, a deionization resin tank 12, a water pump 10, a liquid flow meter 11, a tubular heater 13 and other elements connected by polyvinyl chloride (PVC) pipe fittings to form a closed circulation loop. In addition, it also comprises water pressure gauges, ammeters 3, pH meters, conductivity meters, dissolved oxygen meters and other measuring instruments, and components such as a resistive voltage divider bridge circuit and a direct current power supply to provide direct current high voltage.

[0037] Specifically, the basic component unit of the radiator module comprises an aluminum radiator, a water-cooled resistor 1, equalizing electrodes 4, 5, 6 and 7, and a main and branch water pipe, etc. The main material of the aluminum radiator is 6063 aluminum alloy, and a total of 6 pieces are installed. On the water circuit, each radiator is connected in series with the water-cooled resistor 1 and then connected in communication with the branch water circuit through a hard FEP nozzle, and the radiators are connected in parallel. The simulation parallel cooling circuit is composed of two parts of the main pipe and the branch pipe, and the pipe material, specification and communication mode are consistent with the actual engineering situation: the main water pipe is made of PVDF material with high mechanical strength and high corrosion resistance, and a total of 2 are installed; the branch water pipe is made of soft FEP material. After the main water pipe is connected with the branch water pipe by the FEP hard nozzle, it is connected in communication with the external driving water circuit through a PVC flange. Consistent with the actual engineering, in the parallel cooling simulation system, two pairs of platinum needle-shaped equalizing electrodes E1-E4 are installed at the ends of the main water pipe, and are connected in circuit with the radiators at the two ends to make the potentials of the two radiators always the same.

[0038] The test device is also equipped with a stainless steel test water pump 10, the impeller and other metal parts of which have high corrosion resistance, meeting the needs of simulation fouling test and scale inhibition test. The water inlet and outlet flow of the pump is controlled by a valve, and monitored by a liquid flowmeter 11. The simulated parallel cooling system uses a ±40 kV / 20 mA high-voltage direct current power supply 8 as the test power supply, and a bridge-type resistance voltage dividing circuit is used to distribute the voltage to each radiator. A1-A8 are ammeters 3 fixedly installed on the test platform, which monitor the leakage current of the cooling water flowing into / out of the platinum needle electrode and each radiator. The simulation test platform is installed in the circulating loop in the form of a bypass and is provided with a deionization resin tank 12 before the tank. The use of the deionization resin tank 12 can conveniently reduce the electrical conductivity of the circulating water to the required level. Generally, opening the deionization resin loop for ten minutes can remove most of the ions in the water, so that the electrical conductivity of the circulating water is reduced to below 0.5 μS·cm-1. In the main water pipe, a tubular heater 13 is installed to heat the water in the radiator to the working condition. The device is provided with a water quality measuring tank, which is a tank-shaped container made of transparent organic glass, provided with an organic glass top cover, and sealed by a sealing ring and a fastener. The top cover of the measuring tank is fixedly installed with the measuring electrodes of the conductivity meter, pH meter and dissolved oxygen meter, which can realize online / offline measurement of water quality parameters such as electrical conductivity, pH value and dissolved oxygen content.

[0039] Since the corrosion rate of aluminum radiator is slow under normal pressure conditions, under the condition that 2 kV voltage is applied to the adjacent radiators in the simulation corrosion platform, the concentration of aluminum ions in the water is detected to be 60 μg·L-1 after one month. This concentration is too low to conduct the fouling test, so it is necessary to supplement a sufficient amount of scale-forming ions into the circulating water to accelerate the test.

[0040] As shown in Figure 2 , the simulation method of the above simulation test device comprises: Building a closed circulating water system and filling it with deionized water; Starting the water pump 10 to make the cooling water circulate and adjusting the flow rate through the liquid flowmeter 11; Raising the water temperature to 24-26℃ by using the tubular heater 13; Treating the circulating water by using the deionization resin tank 12 to reduce the electrical conductivity to 0.5 μS·cm -1 below; Selecting the type of chemical reagent according to the target test environment, adding AlCl3 solution under weak acid conditions, adding NaAl(OH)4 solution under weak alkaline conditions, and adding aluminum hydroxide colloid formed by mixing equal volumes of NaAl(OH)4 and dilute hydrochloric acid under neutral conditions to adjust the aluminum ion concentration in the circulating water to about 2.5 mg·L -1 ; The high-voltage direct current power supply is turned on, and a voltage is applied to each radiator through a bridge-type resistance dividing circuit, and an electric field is established through the platinum voltage equalizing electrodes (4, 5, 6, 7) to induce a leakage current; The test is continuously run for at least 336 hours, during which the leakage current is monitored by ammeter 3, and the pH, conductivity and dissolved oxygen are regularly detected by sampling measurement pool 9; After the test is completed, the voltage equalizing electrodes (4, 5, 6, 7) are taken out, and the surface fouling morphology and composition are analyzed by scanning electron microscopy, X-ray diffraction or laser confocal microscopy to evaluate the fouling characteristics under different water quality conditions.

[0041] In the preferred embodiment of the method, under weakly acidic conditions, the cathode-type voltage equalizing electrodes (4, 5, 6, 7) in the low potential area show obvious fouling on the surface, and the thickness of the fouling on the cathode surface facing the high potential anode electrode is greater than that on the anode surface.

[0042] The specific test process of this embodiment is as follows: Before the test starts, a certain amount of solution containing a higher concentration of aluminum ions is added to the circulating water to raise the concentration of scale-forming ions in the water to a higher level, so that more obvious fouling can be observed and more fouling can be observed and analyzed.

[0043] The chemical reagents used for dripping are selected according to the pH value of the water quality. In the weakly acidic environment fouling test, AlCl3 solution is selected; in the weakly alkaline environment fouling test, NaAl(OH)4 solution is selected; in the neutral environment fouling test, the same concentration of NaAl(OH)4 solution and dilute hydrochloric acid are mixed in a ratio of 1:1 to obtain an approximately neutral aluminum hydroxide colloid for dripping. The principle of dripping is to calculate the total concentration of Al(III) used and the total water volume of the platform so that the concentration of aluminum ions in the circulating water after dripping is approximately 2.5 mg·L-1 (about 1000 times the actual in-valve cooling system).

[0044] The initial water quality parameters of the circulating water in the three groups of tests are shown in Table 1.

[0045] Table 1 Initial water quality parameters of acidic, alkaline and neutral circulating water The test results are as follows Figure 3 For weakly acidic environment, obvious fouling is observed on the surface of the electrodes at low potential, i.e. cathode electrodes E3 and E4, and there is a certain difference in the degree of fouling between the cathode surface (i.e. the surface opposite to the anode electrode (E1, E2) in the same manifold) and the anode surface (the other surface): the thickness of the fouling on the cathode surface is slightly greater than that on the anode surface, which may be caused by the greater current on the cathode surface than on the anode surface.

[0046] Six 6063 aluminum heat sinks were arranged in parallel and connected in series with water-cooled resistors to form the cooling loop, which truly reproduced the electrical-thermal coupling relationship between the thyristor heating unit and the cooling system in the converter valve module. The water-cooled resistors simulated the heating characteristics of the thyristor in the on-state, making the heat sinks produce consistent thermal stress distribution in operation; while the parallel pipeline structure (PVDF main pipe + FEP branch pipe) reproduced the fluid mechanics characteristics of uneven flow distribution and local flow stagnation in the engineering, providing a physical basis for studying the corrosion and deposition differences in different flow rate areas. This design ensures the high engineering equivalence of the thermal field and the flow field, and improves the extrapolation value of the test results. Using ±40 kV high-voltage direct current power supply combined with bridge-type resistance voltage division network, the voltage across each heat sink can be accurately controlled to simulate the potential gradient distribution at different positions of the converter valve in the blocking state. Two pairs of platinum needle-shaped voltage grading electrodes (E1-E4) are installed at both ends of the main water pipe and connected to the corresponding heat sinks through the circuit to ensure synchronous change of their potential, which truly reproduces the function of guiding the electric field and suppressing partial discharge of the on-site voltage grading electrode in the high-voltage environment. More importantly, this structure forms a leakage current path from high potential to low potential, driving metal ions (such as Al 3+ ) to migrate directionally under the action of the electric field and deposit in the cathode area, thereby triggering the fouling reaction. This design first realizes the closed-loop simulation of the whole process of "potential distribution-leakage current-ion migration-local deposition" at the laboratory scale. The deionized resin tank is connected to the main circulating loop through a bypass, which can reduce the electrical conductivity of the circulating water to 0.5 μS·cm -1 The following simulates the ultra-low conductivity environment in the actual valve cooling water system to avoid interference of impurity ions with the electrochemical process. On this basis, by quantitatively adding AlCl3, NaAl(OH)4 or aluminum hydroxide colloid to the system, the concentration of aluminum ions in the water is artificially increased to about 2.5 mg·L -1(about 1000 times of the concentration of natural corrosion release), significantly accelerated the generation rate of electrochemical corrosion products and the fouling kinetics process. This "background purification + fouling enhancement" strategy not only ensures the purity of the test environment, but also realizes the accelerated appearance of the fouling phenomenon, solves the problem of long test period and insufficient data caused by slow corrosion in traditional methods, and greatly improves the research efficiency. The sampling and measuring pool integrates a pH, conductivity and dissolved oxygen three-in-one sensor, supporting continuous dynamic monitoring of key water quality parameters of cooling water, real-time capture of local pH changes (such as cathode zone alkalization and anode zone acidification) and dissolved oxygen consumption trend caused by electrochemical reaction, and revealing the chemical driving force of fouling occurrence. At the same time, 8 ammeters (A1~A8) monitor the leakage current of each radiator and the equalizing electrode, respectively, to construct a leakage current distribution map for analyzing the influence of uneven electric field on corrosion rate. The multi-dimensional sensing system provides data support for establishing a dynamic correlation model between "voltage → current → ion release → water quality change → fouling formation", enhancing the scientificity and interpretability of the test. The tubular heater stably controls the circulating water temperature at 24~26℃, close to the actual operating temperature of the converter valve, avoiding the interference of temperature fluctuations on the corrosion rate and the form of fouling; the liquid flow meter cooperates with the water pump to adjust the flow rate, simulating the flow state of cooling water under different working conditions. The research shows that the low flow rate area is more prone to particle deposition and local corrosion, so this module can study the influence of flow rate on the location and density of fouling, and identify the "high-risk area of fouling" in the system. The platform reserves a sampling port and electrode dismounting structure, which facilitates laboratory characterization of the fouling on the surface of the equalizing electrode after the test, such as SEM, XRD, EDS, etc., to determine the phase composition (such as Al(OH)3, Al2O3·nH2O, etc.), micro-morphology and spatial distribution of the fouling. Combined with comparative analysis under different pH conditions, the influence of acid and alkali environment on the crystal form and deposition mechanism of aluminum-based fouling can be revealed, providing a theoretical basis for optimizing water quality control strategies (such as pH control range, corrosion inhibitor addition).

[0047] Example 2 In the converter valve cooling water system corrosion and fouling simulation test device provided in this example, the direct current high-voltage power supply module uses a ±40kV / 20mA high-voltage direct current power supply, which cooperates with a bridge-type resistance voltage dividing circuit to realize voltage distribution among the aluminum radiators.

[0048] The rest is the same as in Example 1.

[0049] Example 3 In the converter valve cooling water system corrosion and fouling simulation test device provided in this example, the platinum needle-shaped equalizing electrodes 4, 5, 6, and 7 have a needle tip portion with a length of 28.5mm and a diameter of 1.8mm, and two pairs of electrodes are arranged at the end of the converging water pipe, one pair as an anode and the other pair as a cathode, which induce metal ion migration and electrochemical deposition under the action of an electric field.

[0050] The rest is the same as Example 1.

[0051] The above describes the basic principles of the present application in conjunction with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above-mentioned specific details are only for the purpose of example and for the purpose of understanding, and the above-mentioned details do not limit the present application to the must-use of the above-mentioned specific details to realize.

[0052] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, alterations, changes, additions and sub-combinations thereof.

[0053] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art without creative work can make many modifications and changes according to the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment on the basis of the prior art according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. A method for combined corrosion and fouling simulation test of a cooling water system of a converter valve, characterized in that The method comprises the following steps: Building a closed loop and filling with deionized water; Using a tubular heater to raise the water temperature to 24-26℃; Adjusting the concentration of scale forming ions and conductivity of the closed loop to achieve an acid-base environment for accelerated simulation of the fouling process, wherein the conductivity is adjusted to 0.5 μS-cm -1 The concentration of aluminum ions in the initial circulating water is adjusted to 2.5 mg-L -1 ; Applying high-voltage direct current to the radiator assembly through a bridge-type resistance voltage divider circuit, and establishing an electric field through the equalizing electrode to induce leakage current; Continuously running for at least 336 hours, periodically detecting water quality parameters by sampling and measuring the pool; After the test, the equalizing electrode is taken out, and the scaling morphology and composition on the surface of the equalizing electrode are analyzed to evaluate the scaling characteristics under different water quality conditions.

2. The method of claim 1, wherein During the continuous running, the leakage current is monitored by an ammeter.

3. The method of claim 1, wherein the method is characterized by: The closed loop is connected by the radiator assembly, the sampling and measuring pool, the water pump, the liquid flow meter, and the tubular heater.

4. The method of claim 3, wherein the method further comprises: The radiator assembly, the sampling and measuring pool, the water pump, the liquid flow meter, and the tubular heater are connected by polyvinyl chloride or fluorinated ethylene propylene copolymer pipe fittings.

5. The combined corrosion and fouling simulation test apparatus for a cooling water system of a converter valve according to claim 1, characterized by, The high-voltage direct current is generated by a ±40kV / 20mA high-voltage direct current power supply.

6. The combined corrosion and fouling simulation test apparatus for a cooling water system of a converter valve according to claim 1, characterized by, The radiator assembly includes a plurality of aluminum radiators arranged in parallel, and the material of the aluminum radiators is 6063 aluminum alloy, which is connected to the branch water pipe through a FEP hard nozzle.

7. The combined corrosion and fouling simulation test apparatus for a cooling water system of a converter valve according to claim 1, characterized by, The aluminum ion concentration in the initial circulating water is adjusted by an aluminum ion-containing solution, which includes AlCl3 solution, NaAl(OH)4 solution, or aluminum hydroxide colloid.

8. A test apparatus for implementing the combined corrosion and fouling simulation test method of a cooling water system of a converter valve as claimed in any one of claims 1 to 7, characterized in that The method comprises: A radiator assembly including a plurality of aluminum radiators arranged in parallel, each aluminum radiator being connected in series with a water-cooled resistor and then connected to a branch waterway to form a parallel cooling structure simulating the internal cooling water system of a converter valve; A circulating loop assembly including a sampling and measuring pool, a water pump, a liquid flow meter, and a tubular heater, which are connected to form a closed loop, and a water quality parameter measuring assembly for online or offline monitoring of water quality parameters of circulating cooling water is built in the sampling and measuring pool; A direct current high-voltage power supply module including a high-voltage direct current power supply, a bridge-type resistance voltage divider circuit, and a platinum needle-shaped equalizing electrode, the bridge-type resistance voltage divider circuit divides the output voltage of the high-voltage direct current power supply to both ends of the radiator assembly, and the platinum needle-shaped equalizing electrode applies an electric field to simulate the leakage current path in actual operation; A water quality control module for adjusting the concentration of scaling ions and the conductivity of the closed loop to accelerate the simulation of the scaling process under different acid-base environments.

9. The test device of claim 8, wherein, The water quality control module includes: A deionization resin tank, connected by a bypass to the closed loop circuit, for reducing the conductivity of the circulating water to 0.5 μS-cm -1 The following: A chemical reagent injection unit for adding an aluminum ion-containing solution to the closed loop circuit to bring the initial aluminum ion concentration to 2.5 mg·L -1 , to achieve an accelerated simulation of the fouling process.

10. The test device of claim 8, wherein, The water quality parameter measuring assembly includes a pH meter, a conductivity meter, and a dissolved oxygen meter.

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