Sacrificial anode residual life evaluation method based on monitoring data

Abstract

The invention discloses a method for evaluating the residual life of a sacrificial anode based on monitoring data. The method comprises the following steps: S1, installing a reference motor and a current sensor; s2, measuring natural potential and initial closed-circuit current between the sacrificial anode block which is not officially used and the reference electrode, and then solving structural resistance through an Ohm law; s3, regularly and daily monitoring the potential difference between the sacrificial anode block and the reference electrode, neglecting the change of the structure resistance, and obtaining a corresponding daily protection current through the Ohm's law; s4, calculating the real-time consumption mass of the sacrificial anode block; s5, accumulating the actual consumption mass of the sacrificial anode block obtained by daily monitoring to obtain the actual consumption mass of the sacrificial anode block; s6, the utilization rate of the sacrificial anode block is evaluated, and a corresponding early warning value is set according to the utilization rate; and S7, establishing a prediction model of the residual service life of the sacrificial anode block. According to the method, the utilization rate and the residual life of the sacrificial anode block can be accurately evaluated in real time.

Description

Technical Field

[0001] The present invention relates to a method for evaluating the remaining life of sacrificial anodes based on monitoring data. Background Art

[0002] In the fields of industrial manufacturing and ocean engineering, sacrificial anodes, as a key anti-corrosion technology, are widely used to protect metal structures from corrosion. Sacrificial anodes are usually economically applied only to structures with small protection current requirements and in environments with low soil resistivity. With the continuous progress of technology and the increasing complexity of engineering environments, higher requirements are put forward for the life management of sacrificial anodes. Traditionally, the utilization rate and remaining life assessment of sacrificial anodes mainly rely on regular manual inspections. This method is not only time-consuming and laborious but also difficult to reflect the actual state of the anodes in real time and accurately.

[0003] In the prior art, although there are some monitoring devices and methods for sacrificial anodes, they still have deficiencies in terms of accuracy, real-time performance, and reliability. For example, some monitoring devices can only provide limited current change data and cannot comprehensively reflect the corrosion process of the anodes; other methods rely on complex electrochemical tests, which are cumbersome to operate and costly. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for evaluating the remaining life of sacrificial anodes based on monitoring data, which can evaluate the utilization rate and remaining life of sacrificial anode blocks in real time and accurately, thereby optimizing the maintenance strategy of equipment, reducing maintenance costs, and improving the reliability and safety of equipment.

[0005] The purpose of the present invention is achieved as follows: A method for evaluating the remaining life of sacrificial anodes based on monitoring data includes the following steps:

[0006] S1. Install monitoring devices. Symmetrically install two reference electrodes on both sides of the steel pipe pile to be protected. The distance between the two reference electrodes and the sacrificial anode block is 0.8 m to 1.2 m, and the burial depth of the two reference electrodes is flush with the sacrificial anode block; install a current sensor in each anode connection circuit. The current sensor is directly fixed on the electrical connection cable between the sacrificial anode block and the steel pipe pile, and the distance from the connection point or cable joint of the sacrificial anode block is ≤0.5 m;

[0007] S2. Measure initial parameters. First, measure the natural potential U and the initial closed-circuit current I between the unused sacrificial anode block and the reference electrode, and then calculate the structural resistance R according to the natural potential U and the initial closed-circuit current I through Ohm's law;

[0008] S3. Daily monitoring and data collection. Regularly monitor the potential difference U between the anode block and the reference electrode i, and ignoring the change in the structural resistance R, the corresponding daily protection current is obtained

[0009] S4. Calculate the real-time consumption mass of the sacrificial anode block. From the daily protection current I i , the actual consumption mass W of the sacrificial anode block within the corresponding time t is obtained through formula (1);

[0010] W = E g I i t (1)

[0011] In the above formula (1):

[0012] t is the service life of a single sacrificial anode block, unit: year;

[0013] E g is the consumption rate of the sacrificial anode block, unit: kg / (A·year);

[0014] S5. Correct the utilization coefficient of the sacrificial anode block. Accumulate the actual consumption mass W of the sacrificial anode block obtained from daily monitoring to obtain the actual consumption mass of the sacrificial anode block; when the actual consumption mass ΣW of the sacrificial anode block = W i μ, it is considered that the sacrificial anode block has been completely consumed; μ is the utilization coefficient of the sacrificial anode block, indicating the proportion of the sacrificial anode block effectively utilized in actual use; W i is the actual weight of a single sacrificial anode block itself, excluding any additional coating, connection parts or other non-anode material parts;

[0015] S6. Life evaluation. Through the formula evaluate the utilization rate of the sacrificial anode block, and set the corresponding warning value accordingly. When the actual consumption mass W of the sacrificial anode block reaches the warning value, a warning is triggered;

[0016] S7. Deploy the prediction model. When the actual consumption mass W of the sacrificial anode block reaches the warning value, establish a prediction model for the remaining service life of the sacrificial anode block, and use the prediction model to calculate the change of the subsequent daily protection current I i so as to realize the evaluation of the remaining service life of the sacrificial anode block.

[0017] For the above method for evaluating the remaining life of the sacrificial anode based on monitoring data, when performing step S1, the reference electrode should be installed avoiding the scouring area.

[0018] The above-mentioned method for evaluating the remaining life of sacrificial anodes based on monitoring data, wherein when performing step S7, the prediction model is a prediction model based on time series analysis, machine learning algorithms or electrochemical mechanism modeling, including at least one of a time series analysis model ARIMA, a recurrent neural network LSTM or a finite element simulation model; when the historical monitoring data is a single current time series signal, the time series analysis model ARIMA is used; when the monitoring data includes environmental parameters, the recurrent neural network LSTM is used; when coupling the electrochemical corrosion kinetics equation, the finite element simulation model is used.

[0019] The method for evaluating the remaining life of sacrificial anodes based on monitoring data according to the present invention is characterized in that it can evaluate the utilization rate and remaining life of sacrificial anode blocks in real time and accurately, and accurately calculate based on the monitoring data to evaluate its utilization rate and remaining life, so as to optimize the equipment maintenance strategy, reduce the maintenance cost, improve the reliability and safety of the equipment, and has important practical significance and application value. This method can not only improve the efficiency and accuracy of managing sacrificial anode blocks, but also promote the informatization and intelligent upgrading of related industries, providing a solid technical guarantee for the long-term stable operation of the equipment. Brief Description of the Drawings

[0020] Figure 1 is a flow chart of the method for evaluating the remaining life of sacrificial anodes based on monitoring data according to the present invention. Detailed Embodiments

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] According to the "Durability Design Standard for Marine Engineering Structures" (JTS153-2015), the service life of a single sacrificial anode can be checked by the following formula:

[0023]

[0024] In the formula, t is the service life (years) of a single sacrificial anode block;

[0025] W i is the net mass (kg) of a single sacrificial anode block;

[0026] E g is the consumption rate [kg / (A·year)] of the sacrificial anode block;

[0027] I' a is the average output current (A) of the sacrificial anode block during the service life, I' a is 0.50 to 0.55 times the initial output current of a single sacrificial anode;

[0028] μ is the utilization coefficient of the sacrificial anode block, representing the proportion of the sacrificial anode block effectively utilized in actual use; for strip-shaped sacrificial anodes, it is taken as 0.85 - 0.90, for bracelet-shaped sacrificial anodes, it is taken as 0.75 - 0.80, and for plate-shaped and other-shaped sacrificial anodes, it is taken as 0.75 - 0.85.

[0029] Check the net mass W of a single sacrificial anode block according to the factory specifications of the sacrificial anode block. i And the utilization coefficient μ of the sacrificial anode block. Obtain the consumption rate E of the sacrificial anode block through electrochemical performance (obtain the inherent material property parameters of the sacrificial anode block through standard electrochemical test methods, including but not limited to open-circuit potential, current efficiency, and electrochemical equivalent, etc. The specific test method shall be implemented in accordance with national standards such as GB / T17848). g Through monitoring means, the real-time output current I' of the sacrificial anode within the service life can be obtained. a From this, the service life t of a single sacrificial anode block can be obtained.

[0030] Please refer to Figure 1 The method for evaluating the remaining life of a sacrificial anode based on monitoring data in the present invention includes the following steps:

[0031] S1. Symmetrically install two reference electrodes on both sides of the steel pipe pile to be protected. Both reference electrodes are 0.8 m - 1.2 m away from the sacrificial anode block, and the burial depth of the two reference electrodes is flush with the sacrificial anode block; install a current sensor in each anode connection circuit. The current sensor is directly fixed on the electrical connection cable between the sacrificial anode block and the steel pipe pile, and the distance from the connection point or cable joint of the sacrificial anode block is ≤ 0.5 m; the selection of the reference electrode should consider its stability, corrosion resistance, and material matching with the sacrificial anode block.

[0032] S2. Measure the initial parameters. First, use a voltmeter and an ammeter to measure the natural potential U and the initial closed-circuit current I between the unused sacrificial anode block and the reference electrode, and then calculate the structural resistance R according to the natural potential U and the initial closed-circuit current I through Ohm's law.

[0033] S3. Daily monitoring and data collection. Regularly monitor the potential difference U between the sacrificial anode block and the reference electrode. i And ignore the change in the structural resistance R to obtain the corresponding daily protection current.

[0034] During daily operation, the structural resistance R may change slightly. The present invention ignores this change and regards the structural resistance R as a constant value. By monitoring the potential difference between the sacrificial anode block and the reference electrode, the corresponding current is obtained, improving the accuracy and reliability of the evaluation result.

[0035] S4. Calculate the real-time consumption mass of the sacrificial anode block. From the daily protection current I i , obtain the mass W actually consumed by the sacrificial anode block within the corresponding time t through formula (1);

[0036] W = E g I i t (1)

[0037] In the above formula (1):

[0038] t is the service life of a single sacrificial anode block, unit: year;

[0039] E g is the consumption rate of the sacrificial anode block, unit: kg / (A·year);

[0040] S5. Correct the utilization coefficient of the sacrificial anode block. Accumulate the actual consumption mass W of the sacrificial anode block obtained from daily monitoring to obtain the actual consumption mass of the sacrificial anode block. When the actual consumption mass ∑W of the sacrificial anode block = W i μ, it is considered that the sacrificial anode block has been exhausted; μ is the utilization coefficient of the sacrificial anode block; W i is the actual weight of a single sacrificial anode block itself, excluding any additional coating, connection parts or other non-anode material parts;

[0041] S6. Evaluate the utilization rate of the sacrificial anode block through the formula , and set the corresponding warning value accordingly. When the actual consumption mass W of the sacrificial anode block reaches the warning value, trigger a warning;

[0042] S7. Deploy a prediction model. When the actual consumption mass W of the sacrificial anode block reaches the warning value, establish a prediction model for the remaining service life of the sacrificial anode block, and use the prediction model to calculate the change of the subsequent daily protection current I i , and then realize the evaluation of the remaining service life of the sacrificial anode block.

[0043] The prediction model is a prediction model based on time series analysis, machine learning algorithm or electrochemistry mechanism modeling, including at least one of the time series analysis model ARIMA, the recurrent neural network LSTM or the finite element simulation model; when the historical monitoring data is a single current time series signal, the time series analysis model ARIMA is used; when the monitoring data includes environmental parameters, that is, includes temperature T, salinity S and resistivity ρ, the recurrent neural network LSTM is used; when coupling the electrochemical corrosion kinetics equation, the finite element simulation model is used. The following uses a specific example to illustrate the present invention.

[0044] A high-piled wharf in a coastal port (pile diameter 1.2 m, pile length 50 m, design life 20 years) uses an aluminum-magnesium alloy sacrificial anode block group (Al-Zn-In system, electrochemical equivalent K = 2.98 g / (A·h), current efficiency η = 0.88) for cathodic protection. The tidal range in the wharf area is 3 - 5 m, and the seawater sediment content is relatively high. It is necessary to monitor the remaining life of the sacrificial anode blocks in a complex environment.

[0045] S1, Install measurement devices

[0046] Symmetrically install two aluminum-magnesium alloy (Zn-AgCl) reference electrodes 1 m below the mud surface of the steel pipe pile (avoiding the scouring area); the burial depths of the two reference electrodes are flush with the sacrificial anode blocks; the reference electrodes provide a reference point for potential measurement, and are used to monitor whether the potential of the protected steel pipe pile is within the anti-corrosion safety range; install a current sensor in each anode connection circuit, and the current sensor is directly fixed on the electrical connection cable between the sacrificial anode block and the protected body, with a distance from the connection point or cable joint of the sacrificial anode block ≤ 0.5 m to ensure the accuracy of signal acquisition; the current sensor is used to measure the current intensity output by the sacrificial anode block in real time, and evaluate the consumption rate and remaining life of the sacrificial anode block;

[0047] S2, Measure initial parameters

[0048] Use a portable potentiostat to measure the natural potential U0 = -0.85 V (vs. Ag / AgCl) between the sacrificial anode block and the reference electrode, and use an ammeter to measure the initial closed-circuit current I0 = 3.2 A between the sacrificial anode block and the reference electrode; then calculate the structural resistance R according to the natural potential U0 and the initial closed-circuit current I0 through Ohm's law:

[0049]

[0050] S3, Daily monitoring and data acquisition

[0051] Deploy an undersea monitoring network and collect monitoring data every 6 hours: The monitoring network includes temperature sensors, salinity sensors, ultrasonic thickness gauges, etc.

[0052] The potential difference U between the sacrificial anode block and the reference electrode i : Transmitted to the onshore control room through optical fiber

[0053] Ambient temperature T: 8 - 28 °C (seasonal fluctuation)

[0054] Salinity S of seawater: 2.8 - 3.2% (affected by river runoff)

[0055] Thickness d of sediment deposition: 0 - 0.3 m (periodic dredging)

[0056] Simultaneously record the anode output current Ii Continuously monitor for 365 days.

[0057] S4. Calculate the real-time consumption mass of the sacrificial anode block

[0058] The consumption rate E of the aluminum-magnesium alloy g = 2.98 kg / (A·year)

[0059] The measured anode output current I on the 180th day i = 2.9 A, the cumulative time t = 180 days

[0060] Calculate the actual consumed mass W of the sacrificial anode block within 180 days according to formula (1)

[0061]

[0062] When accumulated to the 365th day, the total consumed mass W of the sacrificial anode block total = 9.3 kg.

[0063] S5. Correct the utilization factor of the sacrificial anode block

[0064] The sacrificial anode block in this embodiment is cylindrical. The cylindrical anode belongs to other shape types. Or according to the "Durability Design Standard for Marine Engineering Structures" (JTS153 - 2015), the utilization factor range of the cylindrical anode is 0.75 - 0.85, and the recommended value is taken as 0.80 - 0.82. Therefore, the utilization factor μ of the sacrificial anode block is taken as 0.82;

[0065] S6. Life assessment

[0066] The net mass of a single sacrificial anode block is W i = 100 kg (factory nominal value), and the warning threshold is taken as 75%;

[0067] W i μ = 100 * 0.82 * 0.75 = 61.5 kg. When the cumulative consumed mass of the sacrificial anode block reaches 61.5 kg, a warning is triggered;

[0068] S7. Deploy a prediction model. When the actual consumed mass W of the sacrificial anode block reaches the warning value, establish an autoregressive integrated moving average (ARIMA) time series analysis model to estimate the subsequent daily protection current I i and then realize the assessment of the remaining service life of the sacrificial anode block and predict the future usage of the sacrificial anode block.

[0069] The above embodiments are only for illustrating the present invention and are not intended to limit the present invention. Those skilled in the relevant technical fields can also make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by each claim.

Claims

1. An evaluation method for the remaining life of sacrificial anodes based on monitoring data, characterized in that, The evaluation method includes the following steps: S1. Install monitoring devices. Symmetrically install two reference electrodes on both sides of the steel pipe pile to be protected. Both reference electrodes are 0.8 m to 1.2 m away from the sacrificial anode block, and the burial depths of the two reference electrodes are flush with the sacrificial anode block; install a current sensor in each anode connection circuit. The current sensor is directly fixed on the electrical connection cable between the sacrificial anode block and the steel pipe pile, and the distance from the connection point or cable joint of the sacrificial anode block is ≤0.5 m; S2. Measure initial parameters. First, measure the natural potential U and the initial closed-circuit current I between the unused sacrificial anode block and the reference electrode, and then calculate the structure resistance R according to the natural potential U and the initial closed-circuit current I through Ohm's law; S3. Daily monitoring and data collection, by regularly monitoring the potential difference U between the anode block and the reference electrode daily i and ignoring the change in the structural resistance R, the corresponding daily protection current is obtained S4. Calculate the real-time consumption mass of the sacrificial anode block. From the daily protection current I i , obtain the actual consumption mass W of the sacrificial anode block within the corresponding time t through formula (1); W = E g I i t (1) In the above formula (1): t is the service life of a single sacrificial anode block, unit: year; E g The consumption rate of the sacrificial anode block, unit: kg / (A·year); S5. Modify the utilization coefficient of the sacrificial anode block. Accumulate the actual consumption mass W of the sacrificial anode block obtained from daily monitoring to get the actual consumption mass of the sacrificial anode block. When the actual consumption mass ∑W of the sacrificial anode block = W i μ, it is considered that the sacrificial anode block has been completely consumed; μ is the utilization coefficient of the sacrificial anode block, representing the proportion of the sacrificial anode block that is effectively utilized in actual use; W i is the actual weight of a single sacrificial anode block itself, excluding any additional coatings, connectors, or other non-anode material parts; S6, Life assessment, through-type Evaluate the utilization rate of the sacrificial anode block, and set the corresponding warning value accordingly. When the actual consumed mass W of the sacrificial anode block reaches the warning value, a warning is triggered; S7. Deploy a prediction model. When the actual consumption mass W of the sacrificial anode block reaches the warning value, establish a prediction model for the remaining service life of the sacrificial anode block, and use the prediction model to calculate the subsequent daily protection current I i to realize the evaluation of the remaining service life of the sacrificial anode block.

2. The method for evaluating the remaining life of sacrificial anodes based on monitoring data according to claim 1, wherein When performing step S1, avoid the scouring area when installing the reference electrode.

3. The method for evaluating the remaining life of sacrificial anodes based on monitoring data according to claim 1, wherein When performing step S7, the prediction model is a prediction model based on time series analysis, machine learning algorithm or electrochemical mechanism modeling, including at least one of the time series analysis model ARIMA, the recurrent neural network LSTM or the finite element simulation model; when the historical monitoring data is a single current time series signal, use the time series analysis model ARIMA; when the monitoring data includes environmental parameters, use the recurrent neural network LSTM; when coupling the electrochemical corrosion kinetics equation, use the finite element simulation model.

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