Pipeline steel corrosion rate sensor and data transmission system

Abstract

The invention provides a pipeline steel corrosion rate sensor and a data transmission system, the data transmission system adopts multi-wire parallel control, each collector is provided with a split data collection unit, and the collectors are controlled to collect and record data. A plurality of sensors can be mounted on the pipeline, and acquisition terminals of the sensors are connected in parallel through a data transmission bus and then merged into a data analysis transmission bus system to be recorded and transmitted to an upper computer; the corrosion rate sensor is of a planar spiral structure. Two reference electrodes are arranged at the center of the sensor and are used for measuring the corrosion rate by adopting an electrochemical method; and the split data acquisition unit is adopted, so that simultaneous detection of multiple parts of the pipeline is realized, and detection and analysis of the corrosion rate of the pipeline are realized. The electrode with a planar spiral structure can realize a plurality of corrosion rate detection methods. And obvious improvement effects on data fluctuation and errors are achieved when intermediate-frequency impedance is measured. The corrosion current density of the pipeline can be detected by a three-electrode system, and the equipment installation cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of comprehensive detection of pipeline steel corrosion behavior, and in particular to a pipeline steel corrosion rate sensor and a data transmission system. Background Art

[0002] A large number of pipeline steel frames are required for various oil and gas pipelines. X70 and X80 steels are the main steels used for major oil and gas pipelines, and high-strength pipeline steel is the main steel used for energy pipelines in the 21st century. However, pipeline steel is easily affected by the external environment, especially soil environmental corrosion. The soil environmental corrosion problem of pipeline steel is one of the most important engineering and technical problems that threaten the safety of pipeline operation and reduce the life of pipelines. The soil corrosion environment of pipeline steel is a thin liquid film corrosion under the closed coating system. The medium composition is extremely complex. At the same time, the defects and inclusions of the material itself greatly increase the nucleation density caused by local corrosion initiation and cracks, which will significantly increase the sensitivity of local corrosion. Pipeline steel is easily affected by the properties of the soil medium itself because it is buried deep underground. At the same time, it is affected by many environmental factors, such as rainwater, groundwater, oxygen, microorganisms and other corrosive media that penetrate into the gap to form an electrochemical corrosion environment, causing corrosion of various materials until leakage and failure. Moreover, once pipeline steel leaks and fails, it is particularly cumbersome, time-consuming and labor-intensive to survey and repair the leak point.

[0003] The detection of the electrochemical mechanism of the closed thin liquid film environment formed in the soil environment of high-strength pipeline steel and the initiation, evolution and expansion mechanism of local corrosion at different stages of corrosion and key influencing factors has important theoretical value and practical significance. At present, the patents for corrosion monitoring of in-service pipelines on site mainly include: CN 115793089 A provides an underground pipeline detection method and system, but the robot operation cost is high, and the system is relatively complex and cumbersome, and it is impossible to effectively and quickly detect pipeline corrosion.

[0004] CN 114485421 B discloses an underground pipeline detection device, system and method, CN 115046924 A discloses an underground pipeline measurement device and an underground pipeline fault measurement and detection system, and CN 212567511 U discloses an underground comprehensive pipeline detection system. The above patents use various methods to detect in-service pipelines, but do not describe the specific pipeline corrosion detection method and data processing method in detail, and the specific implementation is still difficult. This application uses a special corrosion monitoring probe to achieve effective integration of multiple detection methods, which can detect the complete process of corrosion and provide effective protection for evaluating pipeline corrosion. Summary of the invention

[0005] The purpose of the present invention is to provide a pipeline steel corrosion rate sensor and a data acquisition and transmission system. The data transmission system adopts multi-line parallel control, and each collector has a separate data acquisition unit to control the collector to collect and record data. Multiple sensors can be installed on the pipeline. After the sensor acquisition terminals are connected in parallel by the data transmission bus, they are incorporated into the data analysis transmission bus system to record and transmit to the host computer. The corrosion rate sensor is a planar spiral structure. The two sensors are insulated from each other and there is a gap in the middle. The width of the gap does not exceed 0.1mm. Two Ag-AgCl reference electrodes are installed in the center of the sensor for measuring the corrosion rate by electrochemical methods.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A pipeline steel corrosion rate sensor and data transmission system, including a sensor, a split data acquisition unit and a data analysis transmission bus system. The data transmission system adopts multi-line parallel control, and multiple parallel corrosion sensors can be installed on the pipeline. Each collector has a split independent data acquisition unit to control the collector to collect and record data. The sensor acquisition terminals are connected in parallel by the data transmission bus, and then incorporated into the data analysis transmission bus system for recording and transmission to the host computer. The two sensors are insulated from each other, with a gap in the middle, and the gap width does not exceed 0.1mm; two Ag-AgCl reference electrodes are installed in the center of the sensor for measuring the corrosion rate by electrochemical method.

[0007] The data transmission system is composed of sensors, split data acquisition units and data analysis transmission bus systems. When testing the corrosion rate of pipelines on site, the sensors can be installed on the surface of the pipelines. Multiple sensors can be installed on the same pipeline. The sensors are made of the same material as the pipelines and consist of two flat spiral structure probes. The diameter of the sensors is 5cm-20cm, and the size can be determined according to the site conditions. When in use, place the two probes as Figure 1 As shown in the installation, the two probes are insulated from each other and the gap between the probes is 0.02mm-0.1mm.

[0008] Two Ag-AgCl reference electrodes are installed in the center of the data sensor. The reference electrodes are cylindrical and their length does not exceed the thickness of the sensor. The reference electrodes are used to calibrate the surface potential of the sensor and increase the accuracy of electrochemical measurements.

[0009] When installing the sensor, first clean the corrosion products on the pipeline surface; then spray a small amount of insulating varnish on the side of the sensor that contacts the pipeline, or apply insulating glue on the contact interface to avoid the sensor and the pipeline forming a conductor loop and prevent data signal interference; after placing the sensor on the pipeline, install it together with the pipeline, bury it with soil, or install it under the outer protective layer of the pipeline to ensure that the corrosion environment of the sensor is the same as that of the pipeline.

[0010] After the two test strips and the reference electrode of the sensor are connected by a wire, they are introduced into a split data acquisition unit. The split data acquisition unit includes an AC signal generator and a zero-resistance ammeter. The AC signal generator is connected between the two test strips and can generate five groups of AC signals of high frequency, low frequency and medium frequency between 0.01Hz-10kHz to disturb the sensor. The signal frequency can be set according to the specific situation. The zero-resistance ammeter detects the current and voltage signals between the two test strips, one of which is used as the working electrode, and the other is used as the counter electrode, which is grounded through a wire and connected to the working electrode through the zero-resistance ammeter. The zero-resistance ammeter detects the current signal between the working electrode and the counter electrode, and at the same time detects the potential signal between the working electrode and the Ag-AgCl reference electrode.

[0011] The split data acquisition unit is connected in parallel to the data analysis transmission bus system through the data transmission line. The data analysis transmission bus system includes a central processing control unit, a data acquisition unit, a data storage unit and a data wireless transmission unit. The control, data aggregation and transmission of each split data acquisition unit are realized.

[0012] The wetting state of the sensor surface is determined based on the AC signal. If the surface is dry, the high-frequency impedance measurement result is high. At this time, the current and voltage signals measured by the zero-resistance ammeter can be used to determine whether there is a rust layer on the sensor surface. If the surface is dry, the high-frequency impedance measurement result is low. At this time, the electrical signal acquisition device can be used to measure the current and voltage changes between the two test pieces and the Ag-AgCl reference electrode, and a three-electrode system can be constructed to measure the corrosion rate of the sensor.

[0013] The beneficial effects of the present invention are: 1. The split data acquisition unit is used to achieve simultaneous detection of multiple locations on the pipeline.

[0014] 2. The sensor is installed using a patch, which is the same as the pipeline corrosion environment, realizing the detection and analysis of pipeline corrosion rate.

[0015] 3. The use of planar spiral structure electrodes can realize a variety of corrosion rate detection methods. The reference electrode is installed in the middle, which has a significant improvement effect on data fluctuation and error when measuring the intermediate frequency impedance. Moreover, when the sensor is wetted, the three-electrode system can be used to detect the corrosion current density of the pipeline.

[0016] 4. It can control multiple distributed data acquisition units, reducing the equipment installation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a corrosion sensor; Figure 2 The electrochemical test module completed in the embodiment; Figure 3 It is a schematic diagram of the test results; Figure 2 In the figure, 1 is a central processing control unit; 2 is a data storage unit; 3 is a data acquisition unit; 4 is a wireless data transmission unit; 5 is a separate data acquisition unit; 6 is a transmission antenna; 7 is a pipeline to be detected; and 8 is a corrosion sensor. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the embodiments, but is not limited thereto.

[0019] Example A pipeline steel corrosion rate sensor and data transmission system, comprising a sensor, a split data acquisition unit 5, a data acquisition unit 3 and a data analysis transmission bus system; wherein the data acquisition unit 3 adopts multi-line parallel control, and multiple parallel corrosion sensors 8 can be installed on the pipeline; each collector has a split independent data acquisition unit 3, which controls the collector to collect and record data; the sensor acquisition terminals are connected in parallel by the data transmission bus, and then incorporated into the data analysis transmission bus system to record and transmit to a host computer; the corrosion rate sensor is a planar spiral structure; two sensors are insulated from each other, with a gap in the middle, and the gap width does not exceed 0.1mm; two Ag-AgCl reference electrodes are installed in the center of the sensor for measuring the corrosion rate by an electrochemical method.

[0020] The data transmission system adopts sensors, split data acquisition unit 5 data acquisition unit 3 and data analysis transmission bus system. When detecting the pipeline corrosion rate on site, the sensor is installed on the pipeline surface, and multiple sensors can be installed on the same pipeline; the sensor is made of the same material as the pipeline, and consists of two flat spiral structure probes. The sensor diameter is 5cm-20cm, and the size is determined according to the on-site conditions; when in use, the two probes are installed, the two probes are insulated from each other, and the gap between the probes does not exceed 0.02mm-0.1mm.

[0021] Two Ag-AgCl reference electrodes are installed in the center of the data sensor. The reference electrodes are cylindrical and their length does not exceed the thickness of the sensor. The reference electrodes are used to calibrate the surface potential of the sensor and increase the accuracy of electrochemical measurements.

[0022] When installing the sensor, first clean the corrosion products on the pipeline surface; then spray insulating varnish on the side of the sensor that contacts the pipeline, or apply insulating glue on the contact interface to avoid the sensor and the pipeline from forming a conductor loop and prevent data signal interference; after placing the sensor on the pipeline, install it together with the pipeline, bury it with soil, or install it under the outer protective layer of the pipeline to be tested 7 to ensure that the corrosion environment of the sensor is the same as that of the pipeline to be tested 7.

[0023] After the two test pieces and the reference electrode of the sensor are connected by a wire, they are introduced into the split data acquisition unit 5 data acquisition unit 3; the split data acquisition unit 5 data acquisition unit 3 includes an AC signal generator and a zero-resistance ammeter, wherein the AC signal generator is connected between the two test pieces and can generate five groups of AC signals of high frequency, low frequency and medium frequency between 0.01Hz-10kHz to disturb the sensor; the signal frequency can be set according to specific circumstances; the zero-resistance ammeter detects the current and voltage signals between the two test pieces, wherein one test piece is used as a working electrode, and the other is used as a counter electrode, which is grounded through a wire and connected to the working electrode through the zero-resistance ammeter; the zero-resistance ammeter detects the current signal between the working electrode and the counter electrode, and simultaneously detects the potential signal between the working electrode and the Ag-AgCl reference electrode.

[0024] The split data acquisition unit 5 and the data acquisition unit 3 are connected in parallel to the data analysis transmission bus system through data transmission lines; the data analysis transmission bus system includes a central processing control unit 1, a data acquisition unit 3, a data storage unit 2 and a data wireless transmission unit 4; and realizes the control of each split data acquisition unit 5 and the data acquisition unit 3 and the data aggregation and transmission work.

[0025] The wetting state of the sensor surface is judged according to the AC signal. If the surface is dry, the high-frequency impedance measurement result is high. At this time, it can be judged whether there is a rust layer on the sensor surface according to the current and voltage signals measured by the zero-resistance ammeter; if the surface is dry, the high-frequency impedance measurement result is low. At this time, the electrical signal acquisition device can be used to measure the current and voltage changes between the two test pieces and the Ag-AgCl reference electrode, and a three-electrode system can be constructed to measure the corrosion rate of the sensor.

[0026] Electrochemical test module such as Figure 2 shown.

[0027] Sample preparation: (1) Sensor processing. The sensor is made of X80 pipeline steel and processed into a disc-shaped electrode sheet with a diameter of 8 cm. It is finely cut into two flat spiral structure electrode test pieces. A hole with a diameter of about 1 mm is processed in the center of the test piece, and the Ag-AgCl reference electrode is inserted. The electrode test pieces are insulated from each other, and the gap between them is maintained at 0.08 mm. The two electrode test pieces and the Ag-AgCl reference electrode are respectively led out with wires, and the flat spiral structure electrode is connected according to the attached Figure 1 After installation, the electrode is encapsulated as a whole with epoxy resin, and one side is polished as the working surface.

[0028] (2) Sensor installation. After the pipeline to be tested is half buried underground and the upper part is protected with insulating varnish, the corrosion sensor 8 is installed on the surface of the pipeline to be tested 7, with the working surface of the sensor facing upward. Then, the sensor and the pipeline to be tested 7 are buried in the soil. Multiple sensors can be installed on the surface of the pipeline to be tested 7. After the sensor wires are connected to the upper part-mounted data acquisition unit 5 and the data acquisition unit 3, they are connected in parallel to the data analysis transmission bus system.

[0029] Test method: The central processing control unit 1 sends test instructions to the split data acquisition unit 5 and the data acquisition unit 3 in turn, including impedance measurement and potential-current measurement. The impedance measurement frequency is selected as an AC potential signal disturbance sensor of 0.01Hz; 10Hz; 1kHz; 5kHz; 10kHz. The surface state of the sensor is judged according to the impedance signal. If the surface of the sensor is in a dry state, the corrosion of the pipeline 7 to be detected and the surface of the sensor is relatively slight or non-corroded; if the surface of the sensor is in a wet state or there is a rust layer on the surface, the polarization potential measurement method can be used to apply a dynamic potential disturbance to the sensor to detect the corresponding current signal. According to the impedance data, a zero-resistance ammeter module can also be used to measure the current and potential signals of the sensor.

[0030] The split data acquisition unit 5 and the data acquisition unit 3 send the collected potential, current and impedance data back to the central processing control unit 1. After being sorted by the data storage unit 2, the data wireless transmission unit 4 sends it to the terminal through the transmission antenna 6, or transmits it using the host computer interface.

[0031] Data Analysis: The measurement results are as follows Figure 3 The impedance measurement results show that the impedance modulus reaches about 2TΩ in the dry state; and the impedance modulus is about 1000Ω in the wet state. Other electrochemical tests can be performed in the wet state to detect the corrosion rate of the pipeline 7 to be tested. Matters not covered by the present invention are known technologies.

[0032] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A pipeline steel corrosion rate sensor and data transmission system, characterized in that: The pipeline steel corrosion rate sensor and data transmission system include a sensor, a split data acquisition unit and a data analysis transmission bus system; wherein the data acquisition unit adopts multi-line parallel control, and multiple parallel corrosion sensors can be installed on the pipeline; each collector has a split independent data acquisition unit to control the collector to collect and record data; the sensor acquisition terminals are connected in parallel by the data transmission bus, and then incorporated into the data analysis transmission bus system to record and transmit to the host computer; the corrosion rate sensor is a planar spiral structure; the two sensors are insulated from each other, with a gap in the middle, and the gap width does not exceed 0.1mm; two Ag-AgCl reference electrodes are installed in the center of the sensor for collecting electrochemical method to measure the corrosion rate.

2. A pipeline steel corrosion rate sensor and data transmission system according to claim 1, characterized in that: The pipeline steel corrosion rate sensor and data transmission system adopts a sensor, a split data acquisition unit and a data analysis and transmission bus system; when the pipeline corrosion rate is detected on site, the sensor is installed on the pipeline surface, and multiple sensors can be installed on the same pipeline; the sensor and the pipeline are made of the same material, and are composed of two flat spiral structure probes, and the sensor diameter range is 5cm-20cm; when in use, the two probes are insulated from each other, and the gap between the probes ranges from 0.02mm to 0.1mm.

3. A pipeline steel corrosion rate sensor and data transmission system according to claim 1, characterized in that: Two Ag-AgCl reference electrodes are installed in the center of the sensor. The reference electrodes are cylindrical and their length does not exceed the thickness of the sensor. The reference electrodes are used to calibrate the surface potential of the sensor.

4. A pipeline steel corrosion rate sensor and data transmission system according to claim 1, characterized in that: There is insulating varnish or insulating glue on the contact area between the sensor and the pipeline.

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