An automatic testing device for pipeline corrosion rate

Abstract

The present invention discloses an automatic pipeline corrosion rate testing device, comprising: a power module, a metal test piece probe, a standard signal source, a measurement module, a signal processing module, a positioning module, and a communication storage module. The metal test piece probe comprises: a probe body, a corroded metal test piece, and a compensation metal test piece. The corroded metal test piece is made of the same material as the pipeline being tested and is buried in the soil near the pipeline being tested. The compensation metal test piece is encapsulated within the probe body. The measurement module measures the voltage across the corroded metal test piece and the compensation metal test piece when a standard signal source provides current. The signal processing module calculates the thickness change and corrosion rate of the corroded metal test piece over a certain period of time. The positioning module locates the installation position of the test device. The communication storage module transmits various data signals to a cloud platform and / or a mobile terminal. The present invention can realize online monitoring and evaluation of pipeline corrosion rate and improve monitoring efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum pipeline detection, and more particularly to an automatic testing device for pipeline corrosion rate. Background Art

[0002] With the large-scale construction of UHV transmission lines and buried oil and gas pipelines, the two are increasingly located adjacent to or running parallel to each other. This poses a growing risk of corrosion, perforation, and explosions in oil and gas pipelines due to interference from stray currents in UHV transmission lines. Currently, manual inspection methods using weightless inspection strips are commonly used, but these methods have limitations, requiring frequent manual inspections and pipeline excavation, resulting in low efficiency and a waste of resources.

[0003] Therefore, how to provide an automatic pipeline corrosion rate testing device that can realize online monitoring of pipeline corrosion rate and improve detection accuracy is a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] In view of this, the present invention provides an automatic testing device for pipeline corrosion rate, which can realize online monitoring and evaluation of pipeline corrosion rate and improve monitoring efficiency.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A pipeline corrosion rate automatic testing device includes: a power supply module, a metal test piece probe, a standard signal source, a measurement module, a signal processing module, a positioning module, and a communication storage module; the power supply module supplies power to the standard signal source, the measurement module, the signal processing module, the communication storage module, and the positioning module respectively;

[0007] The metal test piece probe includes: a probe body, a corrosion metal test piece, and a compensation metal test piece; wherein the material of the corrosion metal test piece is consistent with the material of the pipeline to be tested and is buried in the soil near the pipeline to be tested; the compensation metal test piece is encapsulated inside the probe body;

[0008] The standard signal source is used to provide a constant current to the corroded metal test piece and the compensation metal test piece under the control of the signal processing module;

[0009] The measuring module is used to measure the voltage across the corroded metal test piece and the compensation metal test piece at intervals of a preset time period under the control of the signal processing module;

[0010] The signal processing module is used to calculate the thickness change and corrosion rate of the corroded metal specimen within a certain period of time based on the voltage signal measured by the measurement module;

[0011] The positioning module is used to locate the installation position of the test device;

[0012] The communication storage module is used to transmit the corrosion rate of the corroded metal test piece and the location information of the testing device to a cloud platform and / or a mobile terminal.

[0013] Furthermore, it also includes: a reference electrode; the measuring module is used to measure the voltage between the corroded metal test piece and the reference electrode and the voltage between the compensation metal test piece and the reference electrode.

[0014] Furthermore, the measurement module includes two measurement units, each of which includes a voltage attenuation unit, a bias unit and an ADC conversion unit; the voltage attenuation unit is used to attenuate the large voltage existing in the current environment into a smaller voltage by voltage division; the bias unit is used to convert the attenuated voltage into a specific voltage signal that can be input into the ADC conversion unit; the ADC conversion unit is used to convert the specific voltage signal into a corresponding digital signal and output it to the signal processing module.

[0015] Furthermore, the signal processing module includes: a resistance calculation unit, a metal test piece thickness calculation unit and a corrosion rate calculation unit;

[0016] The resistance calculation unit is used to calculate the resistance R of the corroded metal test piece according to the constant current output by the standard signal source, the voltage across the two ends of the corroded metal test piece, and the voltage across the two ends of the compensation metal test piece. C and the resistance R of the compensation metal test piece R ;

[0017] The metal test piece thickness calculation unit is used to calculate the current thickness of the corroded metal test piece according to the resistance changes of the corroded metal test piece and the compensation metal test piece within a certain period of time;

[0018] The corrosion rate calculation unit is used to calculate the corrosion rate according to the thickness change of the corroded metal test piece within a certain period of time.

[0019] Furthermore, the signal processing module further includes: a current density calculation unit; the measurement module further includes: an AC / DC separation unit;

[0020] The AC / DC separation unit is used to separate the AC and DC flowing through the corroded metal test piece by Fourier transform to obtain a DC component and an AC component;

[0021] The current density calculation unit is used to calculate the DC current density of the corroded metal test piece based on the DC component obtained by Fourier transform and the area of the corroded metal test piece, and to calculate the AC current density of the corroded metal test piece based on the AC component obtained by Fourier transform and the area of the corroded metal test piece.

[0022] Furthermore, the signal processing module further includes: a diffusion resistance calculation unit; the diffusion resistance calculation unit is used to calculate the diffusion resistance of the corrosion test piece.

[0023] Furthermore, the signal processing module further includes: an alarm data generating unit;

[0024] The alarm data generating unit is used to compare the corrosion rate and / or corrosion thickness of the corroded metal test piece with a preset threshold value, and generate alarm data when the preset threshold value is exceeded.

[0025] Furthermore, the communication storage module includes: a communication unit and a storage unit;

[0026] The communication unit is used to remotely send various data generated by the signal processing unit and the location information of the test device to a cloud platform or a mobile terminal using 4G+MQTT+JSON;

[0027] The storage unit is used to temporarily store the data to be sent when the communication unit fails to send data.

[0028] Furthermore, the communication unit includes: an RS485 interface, a GPRS interface, an NB-IOT interface and a Bluetooth interface.

[0029] Furthermore, the power supply module is a rechargeable battery, a mains power supply module or a solar power supply module.

[0030] As can be seen from the above technical solution, compared with the existing technology, the present invention provides an automatic pipeline corrosion rate testing device. Through a bimetallic test piece probe composed of a corrosion metal test piece and a compensation metal test piece, the voltage value at both ends of the corrosion metal test piece and the compensation metal test piece is measured in real time. The compensation metal test piece is encapsulated so that it does not contact the soil, thereby ensuring that the thickness of the compensation metal test piece does not change. Based on the positive correlation between the resistance and thickness of the two metal test pieces, the thickness of the corrosion metal test piece is measured, ultimately achieving online monitoring of the pipeline corrosion rate. The present invention does not require frequent manual inspections of pipeline excavation, and can also achieve online automatic monitoring and online evaluation of the pipeline, greatly improving detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the metal test piece probe provided by the present invention;

[0033] Figure 2 A schematic diagram of the connection between the automatic testing device provided by the present invention and the pipeline;

[0034] Figure 3 This is a structural block diagram of the measurement module provided by the present invention. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, an embodiment of the present invention discloses an automatic test device for pipeline corrosion rate, comprising: a power supply module, a metal test piece probe, a standard signal source, a measurement module, a signal processing module, a positioning module, and a communication storage module; the power supply module supplies power to the standard signal source, the measurement module, the signal processing module, the communication storage module, and the positioning module respectively; the power supply module is a rechargeable battery, a mains power supply module, or a solar power supply module;

[0037] The metal test piece probe includes: a probe body, a corrosion metal test piece, and a compensation metal test piece; wherein the corrosion metal test piece is made of the same material as the pipe to be tested and is buried in the soil close to the pipe to be tested; the compensation metal test piece is encapsulated inside the probe body;

[0038] The standard signal source (i.e., constant current source) is used to provide a constant current to the corroded metal test piece and the compensation metal test piece under the control of the signal processing module;

[0039] The measuring module is used to measure the voltage across the corroded metal test piece and the compensated metal test piece at every preset time interval under the control of the signal processing module;

[0040] The signal processing module is used to calculate the thickness change and corrosion rate of the corroded metal specimen within a certain period of time based on the voltage signal measured by the measurement module;

[0041] The positioning module is used to locate the installation position of the test device;

[0042] The communication storage module is used to transmit the corrosion rate of the corroded metal test piece and the location information of the test device to the cloud platform and / or the mobile terminal.

[0043] In one embodiment, it further includes: a reference electrode; a measuring module for measuring the voltage across the corroded metal test piece and the reference electrode and for compensating the voltage across the metal test piece and the reference electrode.

[0044] When the present invention is actually applied, the parameter measurement method is as follows:

[0045] Corrosion rate measurement

[0046] Switch S0 is open, and switches S1 and S2 are closed. The first voltmeter records the voltage between the corroded metal test piece and the reference electrode, while the second voltmeter records the voltage between the compensation metal test piece and the reference electrode. Switches S0, S1, and S2 are relays that are activated at regular intervals under the control of the signal processing module.

[0047] Step 1: Calculate the voltage across the corrosion test piece, which is the voltage recorded by the first voltmeter minus the fixed voltage of the reference electrode, that is, V1;

[0048] Step 2: Calculate the resistance R of the corrosion test piece at this moment based on the known current. C (t), temperature compensation test piece resistance R R (t);

[0049] Step 3: According to the formula:

[0050]

[0051] Calculate the thickness of the corrosion test piece at this moment, calculate the thickness corroded based on the initial thickness, and then calculate the corrosion rate.

[0052] In one embodiment, Figure 3 As shown, the measurement module includes two measurement units, each of which includes a voltage attenuation unit, a bias unit and an ADC conversion unit; the voltage attenuation unit is used to attenuate the large voltage existing in the current environment into a smaller voltage by voltage division; the bias unit is used to convert the attenuated voltage into a specific voltage signal that can be input into the ADC conversion unit; the ADC conversion unit is used to convert the specific voltage signal into a corresponding digital signal and output it to the signal processing module.

[0053] In a specific embodiment, the signal processing module includes: a resistance calculation unit, a metal test piece thickness calculation unit, and a corrosion rate calculation unit;

[0054] The resistance calculation unit is used to calculate the constant current output by the standard signal source and the voltage V at both ends of the corroded metal test piece. C and compensate the voltage V across the metal test piece R , calculate the resistance R of the corroded metal specimen C and the resistance R of the compensation metal test piece R ;

[0055] The metal test piece thickness calculation unit is used to calculate the current thickness of the corroded metal test piece based on the resistance change of the corroded metal test piece and the compensation metal test piece within a certain period of time. The specific calculation formula is as follows:

[0056]

[0057] Among them, d c (t) is the thickness of the corroded metal specimen measured at time t; d(t=0) is the thickness of the corroded metal specimen at the initial time; R C (t=0) is the resistance value of the corroded metal specimen at the initial moment; R R (t=0) is the initial compensation metal test piece resistance value; R C (t) is the resistance value of the corroded metal specimen at time t; R R (t) is the compensated metal test piece resistance value at moment t.

[0058] The corrosion rate calculation unit is used to calculate the corrosion rate based on the thickness change of the corroded metal specimen within a certain period of time. The specific calculation formula is as follows:

[0059]

[0060] Among them, K d is the corrosion rate; d(t=0) is the thickness of the metal test piece at the initial moment, in millimeters (mm); D(t) is the measured thickness of the metal test piece at time t, in millimeters (mm); t is the corrosion time, in years.

[0061] In other embodiments, the signal processing module further includes: a current density calculation unit; the measurement module further includes: an AC / DC separation unit;

[0062] The AC / DC separation unit is used to separate the AC and DC flowing through the corroded metal test piece by Fourier transform to obtain DC component and AC component;

[0063] The current density calculation unit is used to calculate the DC current density of the corroded metal test piece based on the DC component obtained by Fourier transform and the area of the corroded metal test piece, and to calculate the AC current density of the corroded metal test piece based on the AC component obtained by Fourier transform and the area of the corroded metal test piece. The specific calculation formula is:

[0064] AC current density: J AC =I AC / S;

[0065] DC current density: J DC =I DC / S;

[0066] Where S is the area of the corroded metal test piece. In the embodiment of the present invention, the current density is the magnitude of the current per unit area of the test piece, which is equivalent to the leakage per unit area of the corrosion damage point of the pipeline.

[0067] This embodiment aims to separate the AC and DC voltages in a pipeline. A sacrificial anode or a potentiostat is pre-installed in the pipeline under cathode protection. S0 is closed, S1 and S2 are opened, and the voltage across the corrosion test piece is recorded. The recorded voltage represents the AC and DC voltages flowing through the pipeline and the corroded metal test piece. FFT is then used to analyze the DC and AC voltages in the AC and DC voltages, thereby analyzing the interference of stray currents on the pipeline.

[0068] In other embodiments, the signal processing module of the present invention further includes a diffusion resistance calculation unit, which is used to calculate the diffusion resistance of the pipeline to be tested or the corrosion test piece. The diffusion resistance is also a parameter reflecting the corrosion condition of the pipeline. The calculation formula of the diffusion resistance is as follows:

[0069] Where VAC represents the AC voltage flowing through the corroded metal specimen.

[0070] In one embodiment, the signal processing module further includes: an alarm data generating unit;

[0071] The alarm data generating unit is used to compare the corrosion rate and / or corrosion thickness of the corroded metal test piece with a preset threshold value, and generate alarm data when the preset threshold value is exceeded.

[0072] This embodiment can perform online evaluation of the pipeline through alarm data.

[0073] In one embodiment, the communication storage module includes: a communication unit and a storage unit;

[0074] The communication unit is used to remotely send various data generated by the signal processing unit and the location information of the test device to the cloud platform or mobile terminal using 4G+MQTT+JSON; in an embodiment of the present invention, the communication unit sends data once every preset time interval.

[0075] The storage unit is used to temporarily store the data to be sent when the communication unit fails to send data, waiting for the next sending.

[0076] Among them, the communication unit includes: RS485 interface, GPRS interface, NB-IOT interface and Bluetooth interface.

[0077] Specifically, the testing process of the present invention is as follows:

[0078] Step 1: Follow Figure 2 Install the automatic test device. The standard resistor in the figure refers to the sampling resistor, which is used to measure the AC and DC voltage of the pipeline;

[0079] Step 2: The signal processing module controls the standard signal source to output a constant current;

[0080] Step 3: The measurement module completes the voltage measurement of the corroded metal test piece and the compensation metal test piece;

[0081] Step 4: The signal processing module reads the signal from the measurement module in real time and calculates the current density, resistance value and corrosion rate;

[0082] Step 5: Analyze the pipeline status by combining the pipeline corrosion rate and AC / DC voltage and current, determine the pipeline status and alarm level, and send pipeline status signals and alarm status signals to the background according to the corresponding status; pipeline status signals include: whether the pipeline corrosion is serious, whether the pipeline protection potential is normal, and whether the interference from stray current is large.

[0083] Step 6: Send the collected data, pipeline status signal, and alarm level status signal to the background. If the data transmission fails, the data will be temporarily stored in the storage module (SD card) and wait for the next transmission.

[0084] Step 7: Store and analyze the data, pipeline status signals, and alarm level status signals on the cloud platform, and issue alarm information based on the pipeline status signals and alarm level status signals.

[0085] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0086] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An automatic testing device for pipeline corrosion rate, characterized in that: include: Power supply module, metal test piece probe, standard signal source, measurement module, signal processing module, positioning module and communication storage module; The power supply module supplies power to the standard signal source, the measurement module, the signal processing module, the communication storage module and the positioning module respectively; The metal test piece probe includes: a probe body, a corrosion metal test piece, and a compensation metal test piece; wherein the material of the corrosion metal test piece is consistent with the material of the pipeline to be tested and is buried in the soil near the pipeline to be tested; the compensation metal test piece is encapsulated inside the probe body; The standard signal source is used to provide a constant current to the corroded metal test piece and the compensation metal test piece under the control of the signal processing module; The measuring module is used to measure the voltage across the corroded metal test piece and the compensation metal test piece at intervals of a preset time period under the control of the signal processing module; The signal processing module is used to calculate the thickness change and corrosion rate of the corroded metal specimen within a certain period of time based on the voltage signal measured by the measurement module; The positioning module is used to locate the installation position of the test device; The communication storage module is used to transmit the corrosion rate of the corroded metal test piece and the location information of the testing device to the cloud platform and / or the mobile terminal; The device further comprises: a reference electrode; the measuring module is used to measure the voltage between the corroded metal test piece and the reference electrode and the voltage between the compensation metal test piece and the reference electrode; One end of the standard signal source, switch S1, the corroded metal test piece, the compensation metal test piece, switch S2, the reference electrode, and the other end of the standard signal source are connected in this order; a first voltmeter V1 is connected between the corroded metal test piece and the reference electrode; a second voltmeter V2 is connected between the compensation metal test piece and the reference electrode; and the pipeline under test is connected to the connection node between switch S1 and the corroded metal test piece via switch S0; When measuring the corrosion rate, switch S0 is open, and switches S1 and S2 are closed; When measuring stray current, switch S0 is closed, and switches S1 and S2 are open.

2. The automatic testing device for pipeline corrosion rate according to claim 1, characterized in that: The measurement module includes two measurement units, each of which includes a voltage attenuation unit, a bias unit and an ADC conversion unit; the voltage attenuation unit is used to attenuate the large voltage existing in the current environment into a smaller voltage by voltage division; the bias unit is used to convert the attenuated voltage into a specific voltage signal that can be input into the ADC conversion unit; the ADC conversion unit is used to convert the specific voltage signal into a corresponding digital signal and output it to the signal processing module.

3. The automatic testing device for pipeline corrosion rate according to claim 1, characterized in that: The signal processing module includes: a resistance calculation unit, a metal test piece thickness calculation unit and a corrosion rate calculation unit; The resistance calculation unit is used to calculate the resistance R of the corroded metal test piece according to the constant current output by the standard signal source, the voltage across the two ends of the corroded metal test piece, and the voltage across the two ends of the compensation metal test piece. C and the resistance R of the compensation metal test piece R ; The metal test piece thickness calculation unit is used to calculate the current thickness of the corroded metal test piece according to the resistance changes of the corroded metal test piece and the compensation metal test piece within a certain period of time; The corrosion rate calculation unit is used to calculate the corrosion rate according to the thickness change of the corroded metal test piece within a certain period of time.

4. The automatic testing device for pipeline corrosion rate according to claim 3, characterized in that: The signal processing module further includes: a current density calculation unit; the measurement module further includes: an AC / DC separation unit; The AC / DC separation unit is used to separate the AC / DC voltage flowing through the corroded metal test piece by Fourier transform to obtain a DC component and an AC component; The current density calculation unit is used to calculate the DC current density of the corroded metal test piece based on the DC component obtained by Fourier transform and the area of the corroded metal test piece, and to calculate the AC current density of the corroded metal test piece based on the AC component obtained by Fourier transform and the area of the corroded metal test piece.

5. The automatic testing device for pipeline corrosion rate according to claim 4, characterized in that: The signal processing module further includes: a diffusion resistance calculation unit; the diffusion resistance calculation unit is used to calculate the diffusion resistance of the corrosion test piece.

6. The automatic testing device for pipeline corrosion rate according to claim 3, characterized in that: The signal processing module further includes: an alarm data generating unit; The alarm data generating unit is used to compare the corrosion rate and / or corrosion thickness of the corroded metal test piece with a preset threshold value, and generate alarm data when the preset threshold value is exceeded.

7. The automatic testing device for pipeline corrosion rate according to claim 1, characterized in that: The communication storage module includes: a communication unit and a storage unit; The communication unit is used to remotely send various data generated by the signal processing module and the location information of the test device to a cloud platform or a mobile terminal using 4G+MQTT+JSON; The storage unit is used to temporarily store the data to be sent when the communication unit fails to send data.

8. The automatic testing device for pipeline corrosion rate according to claim 7, characterized in that: The communication unit includes: an RS485 interface, a GPRS interface, an NB-IOT interface and a Bluetooth interface.

9. The automatic testing device for pipeline corrosion rate according to claim 1, characterized in that: The power supply module is a rechargeable battery, a mains power supply module or a solar power supply module.

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