Device for measuring corrosion rate of buried storage tank under cathode protection

Abstract

The present invention belongs to the technical field of measurement devices for measuring electrical variables. Provided is a device for measuring the corrosion rate of a buried storage tank under cathode protection. The device comprises: a tank body, a protective plate, bases, spherical heads, corrosion rate measurement mechanisms and a calculation chip. The bases are symmetrically and fixedly connected to the two sides of the bottom of the tank body, and the spherical heads are respectively and fixedly connected to the two ends of the tank body. Guide rails are symmetrically and fixedly connected to inner sides of the protective plate; both ends of each guide rail are fixedly connected to limiting plates, a threaded rod being rotatably connected between the two limiting plates; the outer side of each threaded rod is symmetrically provided with guide rods, the outer side of each threaded rod being threadedly connected to a moving plate, each threaded rod being fixedly connected to an output end of a motor, and the motors being fixedly connected to an inner top wall of the protective plate; one side of each moving plate is provided with a corrosion rate measurement mechanism; and the calculation chip is electrically connected to the corrosion rate measurement mechanisms and is internally provided with a corrosion rate calculation module, which is used for calculating the corrosion rate on the basis of parameters acquired by the corrosion rate measurement mechanisms and a preset mathematical model.

Description

A device for detecting corrosion rate after cathodic protection of soil-covered storage tanks Technical Field

[0001] This invention belongs to the technical field of detection equipment for measuring electrical variables, and specifically relates to a device for detecting the corrosion rate of a soil-covered storage tank after cathodic protection. Background Technology

[0002] Storage tanks, as important industrial equipment, are widely used in petroleum, chemical, and other fields. To prevent leaks and other accidents during use, cathodic protection technology is typically used for corrosion prevention. Cathodic protection involves applying an appropriate current to the tank surface to inhibit corrosion reactions, thereby extending the tank's service life. However, after long-term operation, varying degrees of corrosion can still occur on the tank surface. If this corrosion is not detected and addressed promptly, it may threaten the tank's safety and cause serious environmental pollution incidents.

[0003] To monitor the corrosion status of storage tanks in a timely manner, existing technologies commonly employ electrochemical detection techniques such as the potential-shift method and the electrochemical noise method. The potential-shift method assesses the degree of corrosion by detecting changes in the corrosion potential of the metal surface, but it is significantly affected by factors such as ambient temperature and humidity, making it difficult to obtain accurate corrosion indicators. The electrochemical noise method utilizes the minute current and potential fluctuations generated by the corrosion reaction on the metal surface to analyze the corrosion situation, but the instrument sensitivity is low, making it unable to detect subtle corrosion changes. Furthermore, most of these existing technologies employ point-based detection methods, only obtaining corrosion information from individual parts of the storage tank, making it difficult to comprehensively reflect the overall corrosion status of the tank.

[0004] Meanwhile, most existing detection equipment is installed on the outside of the tank, making it difficult to monitor buried or covered storage tanks in real time. This necessitates that the detection equipment possess certain waterproof, dustproof, and pressure-resistant characteristics to adapt to complex underground environments. However, existing detection equipment is typically large in size, making installation and maintenance inconvenient, thus limiting its application in covered storage tanks.

[0005] Therefore, there is an urgent need for a corrosion rate detection device for soil-covered storage tanks after cathodic protection, which can comprehensively, accurately, and in real time monitor the corrosion status of the storage tanks and provide technical support for the safety assessment and maintenance of the storage tanks. Summary of the Invention

[0006] In view of this, the present invention provides a corrosion rate detection device for cathodic protection of soil-covered storage tanks, which can solve the technical problem that most existing technologies adopt point-based detection methods, which can only obtain corrosion information of individual parts of the storage tank and are difficult to comprehensively reflect the overall corrosion status of the storage tank.

[0007] This invention is implemented as follows:

[0008] This invention provides a corrosion rate detection device for a soil-covered storage tank after cathodic protection, comprising: a tank body, a protective plate, a base, a spherical head, a corrosion rate detection mechanism, and a calculation chip. The tank body has bases symmetrically fixedly connected to both sides of its bottom, and spherical heads fixedly connected to both ends of the tank body. The protective plate has a cuboid structure with guide rails symmetrically fixedly connected to one side of its interior. Limiting plates are fixedly connected to both ends of the guide rails, and a threaded rod is rotatably connected between the two limiting plates. Guide rods are symmetrically arranged on the outer side of the threaded rods, and a movable plate is threadedly connected to the outer side of the threaded rods. The threaded rods are fixedly connected to the output end of a motor, and the motor is fixedly connected to the inner top wall of the protective plate. A corrosion rate detection mechanism is arranged on one side of the movable plate. The calculation chip is disposed inside the protective plate and electrically connected to the corrosion rate detection mechanism. The calculation chip contains a corrosion rate calculation module, which is used to calculate the corrosion rate based on parameters collected by the corrosion rate detection mechanism and a preset mathematical model.

[0009] Based on the above technical solution, the corrosion rate detection device for a soil-covered storage tank after cathodic protection according to the present invention can be further improved as follows:

[0010] The corrosion rate calculation module is used to perform the following steps:

[0011] S10. Measure the electrochemical parameters on the surface of the tank using electrode sensors to obtain potential values, current density values, and metal ion concentration values;

[0012] S20. Establish a corrosion electrochemical model and calculate the corrosion reaction rate constant based on the potential value, the current density value, and the metal ion concentration value.

[0013] S30. Obtain environmental parameters, including soil resistivity, water content, pH value and redox potential;

[0014] S40. Based on the environmental parameters, establish an environmental correction coefficient calculation model;

[0015] S50. Establish a corrosion rate calculation model, combining the corrosion reaction rate constant with the environmental correction coefficient;

[0016] S60. Calculate the instantaneous corrosion rate according to the corrosion rate calculation model;

[0017] S70. The instantaneous corrosion rate is smoothed using the moving time window method to obtain the steady-state corrosion rate;

[0018] S80. Calculate the corrosion depth based on the steady-state corrosion rate and make a corrosion early warning judgment;

[0019] S90. Update the historical database for subsequent corrosion trend analysis.

[0020] The specific calculation model for the corrosion reaction rate constant is as follows:

[0021] ;

[0022] In the formula, is the corrosion reaction rate constant, expressed in millimeters per year; The pre-exponential factor has a range of values ​​of 1. to ; The activation energy is expressed in joules per mole. The gas constant has a value of 8.314 joules per mole Kelvin; This is absolute temperature, measured in Kelvin. Current density, measured in amperes per square meter; The number of electrons transferred in the reaction; is the Faraday constant, with a value of 96485 coulombs per mole.

[0023] The specific calculation model for the environmental correction coefficient is as follows:

[0024] ;

[0025] In the formula, This is an environmental correction factor; Soil resistivity, measured in ohm-meters; The standard soil resistivity is taken as 1000 ohm-meters; Soil moisture content, expressed as a percentage; The standard soil moisture content is taken as 20%. Soil pH; The standard soil pH is set at 7. Redox potential, measured in volts; The standard redox potential is 0.4 volts. , , , These are weighting coefficients, obtained through experimental calibration.

[0026] The corrosion rate calculation model is specifically represented as follows:

[0027] ;

[0028] In the formula, Corrosion rate, expressed in millimeters per year; This is the cathodic protection potential, measured in volts. This is the self-corrosion potential, measured in volts. This is the cathodic protection efficiency coefficient, with a value ranging from 0 to 1.

[0029] The steady-state corrosion rate is calculated using the moving-time window method, as detailed below:

[0030] ;

[0031] In the formula, For a moment steady-state corrosion rate; The length of the time window; The sampling time interval is in hours.

[0032] The specific calculation model for the corrosion depth is as follows:

[0033] ;

[0034] In the formula, For a moment The corrosion depth, in millimeters; It is the integral variable.

[0035] Among them, the weighting coefficient , , , The calibration method is as follows:

[0036] 1. Comparative experiments were conducted under different soil conditions;

[0037] 2. Measure the actual corrosion rate of the test sample;

[0038] 3. The weighting coefficients are obtained by fitting using the least squares method.

[0039] The corrosion rate detection mechanism includes a threaded sleeve, which is cylindrical in shape and has a threaded seat internally connected to it. A telescopic rod is rotatably connected to the center of the threaded seat, and an arc plate is fixedly connected to one end of the telescopic rod. The arc plate is arc-shaped and its inner arc surface matches the outer surface of the tank. An electrode sensor and a cleaning brush are fixedly connected to the inner side of the arc plate. The electrode sensor is used to detect the corrosion potential and current density on the surface of the tank.

[0040] Furthermore, a cathodic protector is fixedly connected to one side of the spherical head. The cathodic protector is electrically connected to an external power source via a waterproof cable. The cathodic protector is used to provide cathodic protection current to the tank. A pipe is fixedly connected to the lower end of one side of the spherical head, and a gas concentration detector is fixedly connected to one end of the pipe.

[0041] Furthermore, the guide rod is fixedly connected between the two limiting plates. The guide rod has a cylindrical structure and a smooth surface. The movable plate is slidably connected to the outside of the guide rod and slides with the guide rod through a built-in bearing.

[0042] Furthermore, sealing strips are provided on both sides of the protective plate. The sealing strips are made of rubber and are tightly fitted to the outer surface of the tank. The protective plate is fixed to the ground by fixing bolts, and the length of the protective plate matches the length of the tank.

[0043] Furthermore, a limiting protrusion is provided on the outer side of the threaded sleeve, and a limiting groove is provided on the movable plate to cooperate with the limiting protrusion. The cooperation between the limiting protrusion and the limiting groove is used to prevent the threaded sleeve from rotating.

[0044] Furthermore, the motor is a stepper motor with adjustable speed. The stepper motor is fixed to the inner wall of the protective plate by a motor mount with a shockproof structure. A coupling is provided between the output shaft of the stepper motor and the threaded rod.

[0045] Furthermore, the base is made of reinforced concrete, the top surface of the base is provided with anti-slip texture, the base is fixedly connected to the ground by expansion bolts, and the height of the base is not less than 50 centimeters.

[0046] Furthermore, the cleaning brush includes a brush body and bristles. The brush body has a cuboid structure and bristles are evenly distributed on its surface. The bristles are made of corrosion-resistant nylon material. The brush body is fixedly connected to the inner surface of the arc plate by screws. The length of the bristles is set according to the roughness of the tank surface.

[0047] Compared with existing technologies, the beneficial effects of the corrosion rate detection device for cathodic protection of soil-covered storage tanks provided by the present invention are:

[0048] 1. Comprehensive Monitoring: The detection device of this invention adopts an integrated detection method. By deploying dense detection mechanisms on the tank surface, it can comprehensively acquire information on the corrosion status of the storage tank, rather than being limited to individual parts. Compared with the point-based detection of existing technologies, this can more accurately reflect the overall corrosion status of the storage tank.

[0049] 2. High-precision analysis: The detection device of this invention combines electrochemical measurement and corrosion model analysis, enabling accurate calculation of key indicators such as instantaneous corrosion rate, steady-state corrosion rate, and corrosion depth. These indicators not only reflect the current corrosion state but also predict future corrosion trends, providing a basis for tank maintenance. Compared to existing technologies that can only obtain single corrosion potential or current information, the analytical method of this invention is more comprehensive and accurate.

[0050] 3. Strong Applicability: The detection device of this invention is specifically designed for buried storage tanks, employing a waterproof and pressure-resistant mechanical structure that can adapt to complex underground environments, solving the problem of existing technologies' difficulty in monitoring buried or buried storage tanks. Furthermore, the device is small in size, facilitating installation and maintenance, and further promotes its widespread application in practical engineering. The motor is a stepper motor with adjustable speed. The stepper motor is fixed to the inner wall of the protective plate via a motor mount with a shock-resistant structure. A coupling is provided between the output shaft of the stepper motor and the threaded rod.

[0051] Furthermore, the base is made of reinforced concrete, the top surface of the base is provided with anti-slip texture, the base is fixedly connected to the ground by expansion bolts, and the height of the base is not less than 50 centimeters.

[0052] Furthermore, the cleaning brush includes a brush body and bristles. The brush body has a cuboid structure and bristles are evenly distributed on its surface. The bristles are made of corrosion-resistant nylon material. The brush body is fixedly connected to the inner surface of the arc plate by screws. The length of the bristles is set according to the roughness of the tank surface.

[0053] Compared with existing technologies, the beneficial effects of the corrosion rate detection device for cathodic protection of soil-covered storage tanks provided by the present invention are:

[0054] 1. Comprehensive Monitoring: The detection device of this invention adopts an integrated detection method. By deploying dense detection mechanisms on the tank surface, it can comprehensively acquire information on the corrosion status of the storage tank, rather than being limited to individual parts. Compared with the point-based detection of existing technologies, this can more accurately reflect the overall corrosion status of the storage tank.

[0055] 2. High-precision analysis: The detection device of this invention combines electrochemical measurement and corrosion model analysis, enabling accurate calculation of key indicators such as instantaneous corrosion rate, steady-state corrosion rate, and corrosion depth. These indicators not only reflect the current corrosion state but also predict future corrosion trends, providing a basis for tank maintenance. Compared to existing technologies that can only obtain single corrosion potential or current information, the analytical method of this invention is more comprehensive and accurate.

[0056] 3. Strong Applicability: The detection device of this invention is specifically designed for buried storage tanks, employing a waterproof and pressure-resistant mechanical structure that can adapt to complex underground environments, solving the problem of existing technologies' difficulty in monitoring buried or buried storage tanks. Furthermore, the device is small in size, facilitating installation and maintenance, and making its widespread application in practical engineering projects possible.

[0057] 4. Intelligent Operation: The detection device of this invention is equipped with a microprocessor chip, enabling automatic detection, analysis, and early warning of corrosion conditions. Detection data can be uploaded to the monitoring center in real time, providing decision support for management personnel. This level of intelligence surpasses the existing manual detection methods.

[0058] In summary, the corrosion rate detection device for cathodic protection of soil-covered storage tanks proposed in this invention has significant improvements in terms of comprehensive monitoring, high-precision analysis, applicability, and intelligence. It provides an effective technical means to improve the safety of storage tanks and extend their service life, and solves the technical problem that most existing technologies adopt point-based detection methods, which can only obtain corrosion information of individual parts of the storage tank and are difficult to comprehensively reflect the overall corrosion status of the storage tank. Attached Figure Description

[0059] Figure 1 is a schematic diagram of the corrosion rate detection device for a soil-covered storage tank after cathodic protection proposed in this invention.

[0060] Figure 2 is a schematic cross-sectional view of the device;

[0061] Figure 3 is a schematic diagram of the internal structure of the device;

[0062] Figure 4 is a schematic diagram of the electrode-related structure;

[0063] Figure 5 is a schematic diagram of the limiting plate structure;

[0064] Figure 6 is a schematic diagram of the relevant structure of the telescopic pole;

[0065] Figure 7 is a flowchart of the steps executed by the corrosion rate calculation module;

[0066] Figure 8 shows the curve of the surface potential value of the storage tank changing over time:

[0067] Figure 9 shows the trend of corrosion rate variation in the storage tank.

[0068] Figure 10 shows the trend of corrosion depth variation in the storage tank.

[0069] In the diagram: 1. Flat ground; 2. Tank body; 3. Spherical head; 4. Base; 5. Cleaning brush; 6. Cathodic protector; 7. Pipeline; 8. Gas concentration detector; 9. Protective plate; 10. Guide rail; 11. Limiting plate; 12. Threaded rod; 13. Guide rod; 14. Moving plate; 15. Motor; 16. Threaded sleeve; 17. Threaded seat; 18. Telescopic rod; 19. Arc plate; 20. Electrode sensor. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0071] Figures 1-6 show a schematic diagram of the corrosion rate detection device for cathodic protection of a soil-covered storage tank provided by the present invention. The device includes a tank body 2 and a protective plate 9. A base 4 is symmetrically fixedly connected to one side of the bottom of the tank body 2. Spherical heads 3 are fixedly connected to both ends of the tank body 2. A guide rail 10 is symmetrically fixedly connected to one side of the inside of the protective plate 9. The length of the protective plate 9 and the internal components are consistent with the length of the soil-covered storage tank and is 76 meters. Limiting plates 11 are fixedly connected to both ends of the guide rail 10. A threaded rod 12 is rotatably connected between the two limiting plates 11. A guide rod 13 is symmetrically arranged on the outside of the threaded rod 12. A movable plate 14 is threadedly connected to the outside of the threaded rod 12. The threaded rod 12 is fixedly connected to the output end of the motor 15. A corrosion rate detection mechanism is arranged on one side of the movable plate 14. During the installation process, the soil-covered storage tank is first positioned and installed, and then the protective plate 9 is installed on the outside of the soil-covered storage tank. Its length is set according to the tank length. The moving plate 14 moves laterally under the threaded rotation of the tank body 2 via the drive motor 15, thereby cooperating with the corrosion rate detection mechanism to move and detect on the surface of the tank body 2. The telescopic rod 18 and the arc plate 19 provided in the corrosion rate detection mechanism are adjustable structures. By rotating the threaded seat 17 provided on the outside of the telescopic rod 18, the telescopic rod 18 pushes the arc plate 19 to fit against the surface of the storage tank under the threaded rotation of the threaded sleeve 16 and the threaded seat 17, thereby making the cleaning brush 5 fit more closely against the surface of the storage tank. In this way, the corrosion efficiency can be obtained by measuring parameters such as corrosion potential and current density. The method of moving and detecting at the same time can reduce the number of electrode sensors installed, thereby reducing costs and improving detection efficiency. It also includes a calculation chip, which is set inside the protective plate and electrically connected to the corrosion rate detection mechanism. The calculation chip is equipped with a corrosion rate calculation module, which is used to calculate the corrosion rate based on the parameters collected by the corrosion rate detection mechanism and the preset mathematical model.

[0072] The corrosion rate calculation module is used to perform the following steps:

[0073] S10. Measure the electrochemical parameters on the surface of the tank using electrode sensors to obtain potential values, current density values, and metal ion concentration values;

[0074] S20. Establish a corrosion electrochemical model and calculate the corrosion reaction rate constant based on the potential value, the current density value, and the metal ion concentration value.

[0075] S30. Obtain environmental parameters, including soil resistivity, water content, pH value and redox potential;

[0076] S40. Based on the environmental parameters, establish an environmental correction coefficient calculation model;

[0077] S50. Establish a corrosion rate calculation model, combining the corrosion reaction rate constant with the environmental correction coefficient;

[0078] S60. Calculate the instantaneous corrosion rate according to the corrosion rate calculation model;

[0079] S70. The instantaneous corrosion rate is smoothed using the moving time window method to obtain the steady-state corrosion rate;

[0080] S80. Calculate the corrosion depth based on the steady-state corrosion rate and make a corrosion early warning judgment;

[0081] S90. Update the historical database for subsequent corrosion trend analysis.

[0082] Preferably, both the tank body 2 and the base 4 are located on top of the flat ground 1.

[0083] Preferably, a cathodic protector 6 is fixedly connected to one side of the spherical head 3.

[0084] Preferably, a pipe 7 is fixedly connected to the lower end of one side of the spherical head 3, and a gas concentration detector 8 is fixedly connected to one end of the pipe 7.

[0085] Preferably, the guide rod 13 is fixedly connected between the two limiting plates 11.

[0086] Preferably, the movable plate 14 is slidably connected to the outside of the guide rod 13.

[0087] Preferably, the motor 15 is fixedly connected to the inside of the guard plate 9.

[0088] Preferably, the corrosion rate detection mechanism includes a threaded sleeve 16, with a threaded seat 17 threadedly connected inside the threaded sleeve 16. A telescopic rod 18 is rotatably connected inside the threaded seat 17. An arc plate 19 is fixedly connected to one end of the telescopic rod 18. An electrode sensor 20 and a cleaning brush 5 are fixedly connected to the inner side of the arc plate 19. The cleaning brush 5 is driven by a motor 15 to slide on the surface of the tank 2 to clean and wipe away water stains adhering to the surface. The electrode sensor 20 is a Heraeus Palnesa 2.

[0089] The working principle and usage procedure of this device are as follows: During use, the device uses a motor to drive the moving plate 14 to move laterally across the surface of the tank 2. This, combined with the corrosion rate detection mechanism, detects the corrosion rate on the tank surface. The motor 15 drives the threaded rod 12 to rotate, causing the moving plate 14 to move laterally along the surface of the tank 2 under the guidance of the guide rod 13. The telescopic rod 18 and the arc plate 19, adjusted by the threaded seat 17, can conform to tank surfaces with different curvatures, ensuring good contact between the electrode sensor 20 and the tank surface. The cleaning brush 5 moves with the moving plate 14, wiping away water stains and other contaminants adhering to the tank surface. Impurities are removed to ensure the measurement accuracy of electrode sensor 20. Electrode sensor 20 measures parameters such as corrosion potential and current density on the tank surface in real time. The host calculates the corrosion rate of the tank based on the measured parameters, combined with the tank material and environmental parameters. This device reduces the number of electrode sensors required by mobile detection, thereby lowering costs and improving detection efficiency. Cleaning brush 5 removes impurities from the tank surface, ensuring the measurement accuracy of electrode sensor 20 and improving detection precision. This device is suitable for soil-covered storage tanks of different shapes and sizes and can adapt to different corrosive environments.

[0090] The specific implementation method of the steps performed by the corrosion rate calculation module is described in detail below:

[0091] The specific implementation of step S10 is as follows: Electrochemical parameters on the surface of the tank are measured using an electrode sensor to obtain the potential value. Current density value and metal ion concentration value First, the surface of the tank is scanned and measured using an electrode sensor to obtain the surface potential value. and current density value Measure the potential value It mainly reflects the change in electrochemical potential during the corrosion reaction process, while the current density value... This reflects the magnitude of the corrosion current. Secondly, an electrochemical analyzer is used to measure the metal ion concentration at the measurement point. Measurements were taken. These electrochemical parameters are the basis for subsequent corrosion rate calculations.

[0092] The specific implementation method of step S20 is as follows: establish a corrosion electrochemical model, based on the potential value. The current density value and the metal ion concentration value Calculate the corrosion reaction rate constant. According to the classic Butler-Volmer equation, the corrosion reaction rate constant... It can be represented as:

[0093] ;

[0094] in, The pre-exponential factor has a range of values ​​of 100. to ; Activation energy, expressed in joules per mole; Here is the gas constant, with a value of Joules per mole Kelvin; Absolute temperature, measured in Kelvin; Current density, measured in amperes per square meter; The number of electrons transferred in the reaction; Let Faraday's constant be denoted as , and its value be . Coulombs per mole. This model, based on the kinetics of the corrosion reaction, assigns the potential value... Current density value and metal ion concentration value Using parameters such as these, the rate constant k of the corrosion reaction was calculated.

[0095] The specific implementation of step S30 is as follows: Obtain environmental parameters, including soil resistivity. Moisture content pH value and redox potential First, the soil resistivity was measured using a soil resistivity meter. The unit is ohmmeter. Then, the soil moisture content is measured using a soil moisture meter. The units are percentages. Next, a pH meter was used to measure the soil pH value. Finally, the redox potential of the soil was measured using a redox potentiometer. The unit is volts. These environmental parameters reflect the corrosivity of the soil and are key factors in subsequent corrosion rate calculations.

[0096] The specific implementation of step S40 is as follows: Based on the environmental parameters, establish an environmental correction coefficient calculation model. Environmental correction factor This reflects the influence of the soil environment on the corrosion rate, and can be expressed as:

[0097] ;

[0098] in, For standard soil resistivity, the value is taken as follows: Omme; Standard soil moisture content, taken as... ; Standard soil pH, taken as value ; The standard redox potential is given by [value]. volt; , , , The weighting coefficients were obtained through experimental calibration. This model can convert measured environmental parameters into corresponding environmental correction coefficients, providing a basis for subsequent corrosion rate calculations.

[0099] The specific implementation of step S50 is as follows: Establish a corrosion rate calculation model, and use the corrosion reaction rate constant... With the environmental correction factor Combined. Corrosion rate. It can be represented as:

[0100] ;

[0101] in, This is the cathodic protection potential, measured in volts. This is the self-corrosion potential, measured in volts. The cathodic protection efficiency coefficient has a range of values. The model multiplies the corrosion reaction rate constant and the environmental correction factor, and takes into account the influence of cathodic protection, to obtain the final corrosion rate.

[0102] The specific implementation of step S60 is as follows: Calculate the instantaneous corrosion rate according to the corrosion rate calculation model. The corrosion reaction rate constant k obtained in step S20 and the environmental correction coefficient obtained in step S40 are used to determine the corrosion rate rate constant k. By substituting the cathodic protection parameters into the corrosion rate calculation model, the instantaneous corrosion rate v at the current moment can be obtained. This instantaneous corrosion rate reflects the real-time corrosion state of the tank surface, providing basic data for subsequent smoothing and corrosion depth calculation.

[0103] The specific implementation of step S70 is as follows: the instantaneous corrosion rate is measured using the moving time window method. Smoothing treatment was performed to obtain the steady-state corrosion rate. The specific formula for the moving time window method is:

[0104] ;

[0105] in, For a moment steady-state corrosion rate; The length of the time window; The sampling time interval is in hours. This method effectively filters out instantaneous fluctuations and obtains a more stable corrosion rate trend by averaging the instantaneous corrosion rate over a certain time range.

[0106] The specific implementation of step S80 is as follows: based on the steady-state corrosion rate Calculate corrosion depth And perform corrosion early warning assessment. Corrosion depth It can be represented as:

[0107] ;

[0108] By integrating the steady-state corrosion rate This allows us to obtain the corrosion depth at the current moment. If the corrosion depth If the value exceeds a preset threshold, such as 5 mm, a corrosion warning will be triggered, and protective measures will be taken in a timely manner.

[0109] The specific implementation of step S90 is as follows: Update the historical database for subsequent corrosion trend analysis, and use the instantaneous corrosion rate v calculated in step S60 and the steady-state corrosion rate calculated in step S70. And the corrosion depth calculated in step S80. Data such as these are stored in a historical database in chronological order. This data can be used to analyze long-term trends in tank corrosion, providing a basis for future maintenance and upkeep.

[0110] Specifically, the principle of this invention is:

[0111] 1. Electrochemical parameter detection: The device has densely packed electrode sensors on the surface of the tank, enabling real-time measurement of the potential value during the corrosion process. Current density value and metal ion concentration values Isoelectric parameters. These parameters reflect the kinetics of the corrosion reaction and form the basis for subsequent corrosion rate calculations.

[0112] 2. Calculation of corrosion reaction rate constant: Based on the measured electrochemical parameters and the Butler-Volmer equation, the corrosion reaction rate constant can be calculated. This constant describes the inherent kinetic characteristics of the corrosion reaction and is related to factors such as temperature and current density.

[0113] 3. Environmental Correction Coefficient Modeling: Besides the kinetic characteristics of the corrosion reaction itself, environmental factors such as soil resistivity, water content, pH value, and redox potential also significantly affect the corrosion rate. Therefore, this invention establishes an environmental correction coefficient calculation model. These environmental parameters are converted into corresponding correction coefficients to provide a basis for subsequent corrosion rate calculations.

[0114] 4. Comprehensive Corrosion Rate Calculation: Finally, this invention proposes a corrosion rate calculation model, which incorporates the corrosion reaction rate constant obtained in step 2. And the environmental correction factor obtained in step 3 Multiplying the values ​​and considering the influencing factors of cathodic protection, the instantaneous corrosion rate is calculated. By smoothing the instantaneous corrosion rate using a moving time window, the steady-state corrosion rate can be obtained. This provides data support for the calculation and early warning of corrosion depth.

[0115] 5. Intelligent Monitoring and Early Warning: The detection device of this invention is equipped with a microprocessor chip, which can automatically complete the above-mentioned electrochemical parameter measurement, corrosion rate calculation, and other processes, and upload the results to the monitoring center. Once the corrosion depth is detected to exceed the preset threshold, the system will automatically issue an early warning signal to remind managers to take necessary maintenance measures. This intelligent monitoring and early warning function greatly improves the efficiency of storage tank safety management.

[0116] By integrating the aforementioned core technologies, the corrosion rate detection device for cathodic protection of soil-covered storage tanks of this invention can comprehensively, accurately, and in real time monitor the corrosion status of the storage tank, providing effective technical support for ensuring the safety of the storage tank and extending its service life. Its innovation lies in fully utilizing electrochemical measurements and corrosion kinetic models to construct a complete intelligent corrosion status monitoring system, overcoming the shortcomings of existing technologies in terms of detection accuracy, comprehensiveness, and applicability.

[0117] The following is an example of a specific application scenario of the present invention: A steel company has a soil-covered storage tank located in a coastal area that has been operating with cathodic protection technology for many years. In order to monitor the corrosion status of the storage tank in real time, the company decided to install and test the corrosion rate detection device for soil-covered storage tanks after cathodic protection proposed in this invention.

[0118] The storage tank is a cylindrical structure with a diameter of 20 meters, a length of 50 meters, and a burial depth of 5 meters. After a comprehensive inspection of the tank, three sets of the detection devices of this invention were installed at the upper, middle, and lower positions on the tank surface. Each detection device consists of a tank body, a protective plate, a base, a spherical end cap, a corrosion rate detection mechanism, and a calculation chip.

[0119] First, the electrochemical parameters of the tank surface were measured using an electrode sensor. As shown in Figure 8, the detection results show the potential value of the tank surface. The current density value varies between -0.85 volts and -0.92 volts. The concentration of metal ions fluctuated between 0.12 amperes per square meter and 0.22 amperes per square meter. Approximately 0.05 grams per liter. These parameters reflect that the surface of the storage tank is in a state of active corrosion.

[0120] Secondly, based on the measured electrochemical parameters, the rate constant of the corrosion reaction was calculated. Assuming a pre-exponential factor Pick ,activation energy for kilojoules per mole, temperature The electron transfer number is 298 Kelvin. If the value is 2, then we can obtain:

[0121] millimeters per year;

[0122] This value indicates that, under the current corrosive environmental conditions, the inherent corrosion reaction rate on the tank surface is relatively fast.

[0123] Next, the environmental parameters of the soil where the storage tank is located were measured: resistivity for Ommeter, moisture content for pH value for Oxidation-reduction potential for Volts. Substituting these parameters into the environmental correction factor calculation model, we obtain:

[0124] ;

[0125] This correction factor indicates that the current soil environment has a certain accelerating effect on the corrosion of storage tanks.

[0126] Then, the data obtained in steps 2 and 3 are substituted into the corrosion rate calculation model, assuming the cathodic protection potential. for Volt, self-corrosion potential for Volt, cathodic protection efficiency coefficient for The instantaneous corrosion rate was calculated. for:

[0127] millimeters per year;

[0128] This instantaneous corrosion rate reflects the real-time corrosion state of the tank surface at the current moment.

[0129] To further improve the stability of corrosion rate prediction, this invention employs a moving time window method to smooth the instantaneous corrosion rate. Assuming a time window length of... The sampling time interval is 6. If the time is 2 hours, the steady-state corrosion rate can be calculated. for:

[0130] millimeters per year;

[0131] By integrating the steady-state corrosion rate This allows us to obtain the corrosion depth at the current moment. for:

[0132] millimeters;

[0133] Since the corrosion depth has not exceeded the preset 5 mm threshold, the system did not trigger a corrosion warning.

[0134] To further analyze the long-term trend of tank corrosion, the detection device of this invention records the above detection data and stores it in a historical database. Table 1 shows some data within 6 months:

[0135] Table 1 Corrosion Detection Data for Storage Tanks

[0136]

[0137] As can be seen from the data in Table 1, the potential value on the surface of the storage tank decreases with increasing usage time. Gradually decrease, current density and metal ion concentration The rate also shows an upward trend, indicating that the corrosion problem is becoming increasingly serious. The calculated instantaneous corrosion rate... and steady-state corrosion rate The instantaneous corrosion rate is also constantly increasing, reflecting the intensification of corrosion. As shown in Figure 9, the instantaneous corrosion rate on the surface of the storage tank increases over time. and steady-state corrosion rate All showed an upward trend, which is related to the potential value. The downward trend is consistent. Finally, Figure 10 shows the corrosion depth of the storage tank. Changes: Clearly showing the corrosion depth on the surface of the storage tank. Over time, the magnitude of the particle size gradually increased from an initial 0.72 mm to 1.83 mm, approaching the warning threshold of 5 mm.

[0138] Based on the above detection data and trend analysis, the following conclusions can be drawn:

[0139] 1. The surface of the storage tank is in a state of severe corrosion, and the corrosion problem is constantly worsening. The decrease in potential value, increase in current density, and increase in metal ion concentration reflect the increasingly active nature of the corrosion reaction.

[0140] 2. Both the instantaneous corrosion rate and the steady-state corrosion rate show a continuous upward trend, and the corrosion rate is accelerating. If effective measures are not taken, the service life of the storage tank will be significantly shortened.

[0141] 3. The corrosion depth on the surface of the storage tank is approaching the warning threshold and is very likely to exceed the threshold within the next 6 months. At that time, emergency maintenance measures must be taken to ensure the safe use of the storage tank.

[0142] Based on the above analysis results, the steel company decided to carry out maintenance and repair of the storage tank as soon as possible, and at the same time strengthen the daily inspection and data analysis of the detection device of the present invention to provide reliable technical support for the safe operation of the storage tank.

[0143] In summary, the corrosion rate detection device for cathodic protection of soil-covered storage tanks proposed in this invention can comprehensively, accurately, and in real time monitor the corrosion status of the storage tank, providing an effective technical means to ensure the safety of the storage tank and extend its service life.

[0144] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for detecting the corrosion rate of a soil-covered storage tank after cathodic protection, characterized in that, include: The system comprises a tank body, a protective plate, a base, spherical heads, a corrosion rate detection mechanism, and a computing chip. The tank body has bases symmetrically fixed to both sides of its bottom, and spherical heads fixed to both ends. The protective plate is a cuboid structure with guide rails symmetrically fixed to one side of its interior. Limit plates are fixed to both ends of the guide rails, and a threaded rod is rotatably connected between the two limit plates. Guide rods are symmetrically arranged on the outer side of the threaded rod, and a movable plate is threadedly connected to the outer side of the threaded rod. The threaded rod is fixedly connected to the output end of a motor, and the motor is fixedly connected to the inner top wall of the protective plate. A corrosion rate detection mechanism is located on one side of the movable plate. The computing chip is electrically connected to the corrosion rate detection mechanism and contains a corrosion rate calculation module. This module calculates the corrosion rate based on parameters collected by the corrosion rate detection mechanism and preset parameters. The mathematical model calculates the corrosion rate; the corrosion rate detection mechanism includes a threaded sleeve, which is cylindrical in shape and has a threaded seat internally connected to it. A telescopic rod is rotatably connected to the center of the threaded seat, and one end of the telescopic rod is fixedly connected to an arc plate. The arc plate has an arc shape, and its inner arc surface matches the outer surface of the tank. An electrode sensor and a cleaning brush are fixedly connected to the inner side of the arc plate. The electrode sensor is used to detect the corrosion potential and current density on the surface of the tank. A cathodic protector is fixedly connected to one side of the spherical head. The cathodic protector is electrically connected to an external power source via a waterproof cable and is used to provide cathodic protection current to the tank. A pipe is fixedly connected to the lower end of one side of the spherical head, and a gas concentration detector is fixedly connected to one end of the pipe. The corrosion rate calculation module is used to perform the following steps: S10. Measure the electrochemical parameters on the surface of the tank using electrode sensors to obtain potential values, current density values, and metal ion concentration values; S20. Establish a corrosion electrochemical model and calculate the corrosion reaction rate constant based on the potential value, the current density value, and the metal ion concentration value. S30. Obtain environmental parameters, including soil resistivity, water content, pH value and redox potential; S40. Based on the environmental parameters, establish an environmental correction coefficient calculation model; S50. Establish a corrosion rate calculation model, combining the corrosion reaction rate constant with the environmental correction coefficient; S60. Calculate the instantaneous corrosion rate according to the corrosion rate calculation model; S70. The instantaneous corrosion rate is smoothed using the moving time window method to obtain the steady-state corrosion rate; S80. Calculate the corrosion depth based on the steady-state corrosion rate and make a corrosion early warning judgment.

2. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 1, characterized in that, The corrosion rate calculation module also includes step S90, updating the historical database for subsequent corrosion trend analysis.

3. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 2, characterized in that, The guide rod is fixedly connected between the two limiting plates. The guide rod has a cylindrical structure and a smooth surface. The movable plate is slidably connected to the outside of the guide rod. The movable plate is slidably engaged with the guide rod through a built-in bearing.

4. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 3, characterized in that, The protective plate is provided with sealing strips on both sides. The sealing strips are made of rubber and are tightly attached to the outer surface of the tank. The protective plate is fixed to the ground by fixing bolts, and the length of the protective plate matches the length of the tank.

5. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 4, characterized in that, The threaded sleeve has a limiting protrusion on its outer side, and the movable plate has a limiting groove that mates with the limiting protrusion. The mate between the limiting protrusion and the limiting groove is used to prevent the threaded sleeve from rotating.

6. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 5, characterized in that, The motor is a stepper motor with adjustable speed. The stepper motor is fixed to the inner wall of the protective plate by a motor mount with a shockproof structure. A coupling is provided between the output shaft of the stepper motor and the threaded rod.

7. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 6, characterized in that, The base is made of reinforced concrete, and the top surface of the base is provided with anti-slip texture. The base is fixed to the ground by expansion bolts, and the height of the base is not less than 50 centimeters.

8. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 7, characterized in that, The cleaning brush includes a brush body and bristles. The brush body has a cuboid structure and bristles are evenly distributed on its surface. The bristles are made of corrosion-resistant nylon material. The brush body is fixedly connected to the inner surface of the arc plate by screws. The length of the bristles is set according to the roughness of the tank surface.

9. The corrosion rate detection device for a soil-covered storage tank after cathodic protection according to claim 8, characterized in that, The computing chip is located inside the protective plate.

Images