Method, device and system for monitoring the inner surface of a cryogenic pipeline of an lng

Abstract

The application provides a pipeline monitoring method, device and system for inner surface cracks of LNG cryogenic pipelines, the method comprising: based on the geometric characteristics of the inner surface cracks of the LNG cryogenic pipelines, arranging multiple sensors on the outer surface of the LNG cryogenic pipelines to generate pipeline strain observation values, temperature sensing data and vibration sensing data; and based on the pipeline strain observation values, the temperature sensing data, the vibration sensing data and strain reference values, monitoring the pipeline state and crack fatigue life of the LNG cryogenic pipelines. Through arranging multiple types of sensors on the outer surface and fusing multiple source data such as strain, temperature and vibration, non-invasive and high-reliability monitoring of the inner surface crack state of the pipelines is realized, the real expansion signal can be effectively distinguished from the working condition interference, and the accuracy of state judgment is improved. Meanwhile, the sensor arrangement and protection process adopted ensures long-term stable operation of the system in the low-temperature condensation environment, and provides integrated technical support for pipeline safety early warning and life assessment.

Description

Technical Field

[0001] This invention relates to the field of pipeline monitoring technology, and in particular to a pipeline monitoring method, apparatus and system for cracks on the inner surface of LNG cryogenic pipelines. Background Technology

[0002] During operation, liquefied natural gas (LNG) cryogenic pipelines may develop defects such as cracks on their inner surface due to the long-term effects of low temperatures, pressure fluctuations, and complex operating conditions. If these defects are not detected and monitored in a timely manner, they may gradually expand and lead to leaks or even safety accidents. However, LNG pipelines are typically encased in insulation and are in a continuous, interconnected state, making effective isolation or shut-off impossible, and direct detection or repair of internal surface cracks is not feasible. Therefore, developing a technology that can continuously and accurately monitor the state of internal surface cracks without affecting the normal operation of the pipeline is of significant engineering importance for ensuring the safe operation of cryogenic pipelines and enabling predictive maintenance.

[0003] Currently, monitoring methods for pipeline cracks mainly include optical detection and external monitoring based on a single parameter. Optical detection methods have poor applicability and insufficient stability in low-temperature, condensation-prone pipeline surface environments. Existing external monitoring technologies mostly rely on a single type of sensor (such as using only strain gauges), which are easily affected by condensation and low-temperature adhesive failure when attached to low-temperature pipeline surfaces, resulting in low sensor adhesion reliability and short lifespan. Furthermore, relying solely on strain as a single parameter makes it difficult to distinguish between the true strain change caused by crack propagation and interference signals caused by external factors, easily leading to false alarms or missed detections, thus limiting the accuracy and reliability of monitoring results.

[0004] In summary, existing pipeline crack monitoring technologies suffer from difficulties in implementation, poor environmental adaptability, insufficient sensor reliability, and high false alarm rates due to reliance on a single monitoring parameter. Therefore, there is an urgent need for an online crack condition monitoring and early warning method suitable for cryogenic pipeline operating environments, capable of multi-parameter collaborative monitoring and fusion analysis, and possessing both high reliability and high accuracy. This method would compensate for the shortcomings of existing technologies and improve the level of intelligent pipeline safety management.

[0005] This section is intended to provide background or context for the embodiments of this application set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section. Summary of the Invention

[0006] One objective of this invention is to provide a pipeline monitoring method for internal surface cracks in LNG cryogenic pipelines. By deploying multiple types of sensors on the outer surface and fusing multi-source data such as strain, temperature, and vibration, a non-invasive and highly reliable monitoring method for the crack state on the pipeline's inner surface is achieved. This method effectively distinguishes between real propagation signals and operational interference, improving the accuracy of condition assessment. Simultaneously, the sensor deployment and protection technology employed ensures the long-term stable operation of the system in cryogenic and condensation-prone environments, providing integrated technical support for pipeline safety early warning and life assessment. Another objective of this invention is to provide a pipeline monitoring device for internal surface cracks in LNG cryogenic pipelines. Yet another objective of this invention is to provide a pipeline monitoring system for internal surface cracks in LNG cryogenic pipelines. A further objective of this invention is to provide a computer-readable medium. A final objective of this invention is to provide a computer device.

[0007] To achieve the above objectives, this invention discloses a pipeline monitoring method for cracks on the inner surface of LNG cryogenic pipelines, comprising: Based on the geometric characteristics of the cracks on the inner surface of the LNG cryogenic pipeline, a variety of sensors are installed on the outer surface of the LNG cryogenic pipeline. Multi-source data is collected by multiple sensors to generate pipeline strain observation values, temperature sensing data and vibration sensing data; The pipeline condition of LNG cryogenic pipelines is monitored based on pipeline strain observations, temperature sensing data, and strain benchmark values. Crack fatigue life of the pipeline is generated based on vibration sensing data, and the strain benchmark values ​​are calculated based on geometric features.

[0008] Preferably, based on the geometric characteristics of cracks on the inner surface of the LNG cryogenic pipeline, multiple sensors are installed on the outer surface of the LNG cryogenic pipeline, including: Based on the geometric features, mark the crack geometry at the corresponding position on the outer surface; Based on the crack geometry markings, multiple strain sensors are set at the crack tip, both sides of the crack, and at a position at a distance of the first length from the crack. Based on the crack geometry, multiple circumferential orientations are selected at the second axial length position of the cross section where the crack is located, and multiple temperature sensors are set at the selected circumferential orientations. Based on the crack geometry, multiple vibration sensors are installed at a position three axial lengths away from the cross section where the crack is located.

[0009] Preferably, multiple strain sensors are provided, including: Remove the insulation layer of the LNG cryogenic pipeline according to the bonding area of ​​the strain sensor; The exposed pipeline body after dismantling was purged with gas and cleaned. The strain sensor is attached to the cleaned area using a polytetrafluoroethylene (PTFE) membrane. Apply low-temperature resistant sealant along the edge of the polytetrafluoroethylene film for sealing; Perform state initialization on the sealed strain sensor to complete the strain sensor setup.

[0010] Preferably, multiple temperature sensors are provided, including: Cleaning operations are performed on the LNG cryogenic pipeline; Multiple temperature sensors are fixed to the outer surface of the LNG cryogenic pipeline using clamps.

[0011] Preferably, multiple vibration sensors are provided, including: Cleaning operations are performed on the LNG cryogenic pipeline; Multiple vibration sensors are fixed to the outer surface of the LNG cryogenic pipeline using clamps.

[0012] Preferably, the multi-source data includes strain sensing data; Generate pipe strain observations, including: Based on the strain sensing data collected by strain sensors at the crack tip and both sides of the crack, and the strain sensing data collected by strain sensors at the first length distance from the crack, strain observation values ​​for the pipeline are generated.

[0013] Preferably, monitoring the pipeline condition of LNG cryogenic pipelines based on pipeline strain observations, temperature sensing data, and strain reference values ​​includes: Based on the strain benchmark value, determine whether the pipeline strain observation value is within the first fluctuation range; If it falls within the first fluctuation range, the pipeline status is determined to be normal; If it is outside the first fluctuation range, determine whether the LNG cryogenic pipeline is in operation based on temperature sensor data. If the pipeline is in operation, determine whether the observed strain value is within the second fluctuation range; If the pipeline is within the second fluctuation range, the pipeline status is determined to be abnormal, and a parameter warning is issued. If the crack propagation is outside the second fluctuation range, the pipeline condition is determined to be abnormal, and a crack propagation warning is issued. If the pipeline is not in operation, the system will determine that the sensors and monitoring equipment are malfunctioning and issue an equipment warning.

[0014] Preferably, the crack fatigue life of the pipeline is generated based on vibration sensing data, including: Based on the vibration sensing data, the pipeline vibration frequency parameters are generated according to the first time interval. Based on a pre-established finite element model, load identification and stress analysis are performed according to vibration frequency parameters to generate stress amplitude. By using a preset stress-life curve, the crack fatigue life of the pipeline corresponding to the stress amplitude is determined.

[0015] Preferably, the method further includes: According to the second time interval, the geometric characteristics of the inner surface cracks in the LNG cryogenic pipeline are remeasured and updated; Based on geometric features, the strain reference values ​​are recalculated and updated.

[0016] This invention also discloses a pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline, comprising: The sensor setting unit is used to set multiple sensors on the outer surface of the LNG cryogenic pipeline based on the geometric characteristics of the cracks on the inner surface of the pipeline. The data generation unit is used to collect multi-source data through multiple sensors and generate pipeline strain observation values, temperature sensing data, and vibration sensing data; The pipeline condition monitoring unit is used to monitor the pipeline condition of LNG cryogenic pipelines based on pipeline strain observations, temperature sensing data, and strain reference values. It also generates the crack fatigue life of the pipeline based on vibration sensing data, and the strain reference values ​​are calculated based on geometric features.

[0017] The present invention also discloses a pipeline monitoring system for cracks on the inner surface of an LNG cryogenic pipeline, comprising: the system including: an LNG cryogenic pipeline, multiple sensors, a pipeline monitoring device as described above, a network transmission medium, and a display device; The inner surface of the LNG cryogenic pipeline has cracks, and the outer surface is equipped with various sensors. The pipeline monitoring device is connected to various sensors on the outer surface of the LNG cryogenic pipeline via cables. The network transmission medium is connected to the pipeline monitoring device, which wirelessly transmits the pipeline status of the LNG cryogenic pipeline to the display device through the network transmission medium. The display device provides a visual representation of the LNG cryogenic pipeline's status.

[0018] The present invention also discloses a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the method described above.

[0019] The present invention also discloses a computer device, including a memory and a processor, wherein the memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions, wherein the processor executes the program to implement the method described above.

[0020] The present invention also discloses a computer program product, including a computer program / instruction, which, when executed by a processor, implements the method described above.

[0021] This invention, based on the geometric characteristics of cracks on the inner surface of LNG cryogenic pipelines, installs multiple sensors on the outer surface of the pipeline. These sensors collect multi-source data, generating pipeline strain observations, temperature sensing data, and vibration sensing data. The pipeline condition is monitored based on the strain observations, temperature sensing data, and strain benchmark values. Furthermore, the crack fatigue life of the pipeline is generated based on the vibration sensing data. The strain benchmark value is calculated based on geometric characteristics. By deploying multiple types of sensors on the outer surface and fusing multi-source data such as strain, temperature, and vibration, non-invasive and highly reliable monitoring of the crack state on the inner surface of the pipeline is achieved. This effectively distinguishes between real propagation signals and operational interference, improving the accuracy of condition assessment. Simultaneously, the sensor deployment and protection technology ensures long-term stable operation of the system in cryogenic, condensation-prone environments, providing integrated technical support for pipeline safety early warning and life assessment. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a pipeline monitoring system for cracks on the inner surface of an LNG cryogenic pipeline, provided in an embodiment of the present invention. Figure 2 A flowchart illustrating a pipeline monitoring method for inner surface cracks in an LNG cryogenic pipeline, provided as an embodiment of the present invention; Figure 3 A flowchart of another pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines provided in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating a strain sensor adhesive protection method according to an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating a temperature sensor adhesive protection method according to an embodiment of the present invention. Figure 6 A schematic diagram illustrating the adhesive protection of a vibration sensor according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline, provided in an embodiment of the present invention. Figure 8This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To facilitate understanding of the technical solution provided in this application, the relevant content of the technical solution will be explained below. For LNG cryogenic pipelines, due to the cryogenic characteristics of the transported medium and the complexity of the operating conditions, once cracks appear on the inner surface of the pipeline, it is often difficult to immediately shut down for repair or pipe section replacement. To ensure the long-term safe operation of the pipeline and improve risk prevention and control capabilities, it is necessary to implement online condition monitoring of identified inner surface cracks. This application, by tracking the development dynamics of cracks in real time and comprehensively assessing their safety status based on multi-source monitoring data, can provide timely warnings and initiate emergency response when abnormal crack propagation occurs, thereby realizing the transformation from passive maintenance to active protection and effectively improving the overall emergency response level of the pipeline system.

[0026] Figure 1 This is a schematic diagram of a pipeline monitoring system for cracks on the inner surface of an LNG cryogenic pipeline, provided in an embodiment of the present invention. Figure 1 As shown, the system includes: an LNG cryogenic pipeline, various sensors (strain sensors, temperature sensors, and vibration sensors), a pipeline monitoring device, a network transmission medium, and a display device.

[0027] The inner surface of the LNG cryogenic pipeline has cracks, and the outer surface is equipped with various sensors. The pipeline monitoring device communicates with the various sensors on the outer surface of the LNG cryogenic pipeline via cables. The network transmission medium communicates with the pipeline monitoring device, and the pipeline monitoring device wirelessly transmits the pipeline status of the LNG cryogenic pipeline to the display device via the network transmission medium. The display device visualizes the pipeline status of the LNG cryogenic pipeline.

[0028] It is worth noting that the pipeline monitoring device converts the signals collected by the sensors into digital signals for further analysis. The analysis process is detailed in [link to analysis]. Figure 2 or Figure 3 The pipeline monitoring methods for cracks on the inner surface of LNG cryogenic pipelines will not be elaborated here.

[0029] In this embodiment of the invention, the LNG cryogenic pipeline is the object of monitoring, and its inner surface has cracks and defects that need to be monitored. The side profile of the pipeline is... Figure 1The location of the crack is indicated by a thick black solid line. Figure 1 It is shown in dashed lines.

[0030] In this embodiment of the invention, the various sensors include strain sensors, temperature sensors, and vibration sensors. Specifically, the number of strain sensors is at least five, the number of temperature sensors is at least one, and the number of vibration sensors is at least one.

[0031] like Figure 1 As shown, strain sensors are represented by solid black circles. As an optional solution, resistance strain gauges are used as strain sensors. The placement of the strain sensor is determined based on the corresponding position of the projection of the crack on the inner surface onto the outer surface, such as: directly above the crack tip, on either side of the crack, or at a point at the first length from the crack. The function of the strain sensor is to detect localized micro-strain changes in the pipe wall caused by internal pressure, external load, or crack propagation, and to convert the strain signal into a resistance change signal.

[0032] In this embodiment of the invention, when the pipeline is subjected to pressure or external force, the crack and the pipeline will be subjected to force, causing the strain to change. The strain sensor can capture this change. When the crack extends from the inner surface to the outer surface, the strain response is more significant the closer it is to the outer surface. When a significant change trend different from the normal working condition appears, it can be considered that the crack has extended and the safety of the crack needs to be closely monitored.

[0033] Temperature sensors are indicated by solid green circles. As an optional solution, thermocouples or resistance temperature detectors (RTDs) can be used. The temperature sensors are installed at different clock positions in the axially adjacent region of the crack on the outer wall of the pipeline. The function of the temperature sensors is to measure the temperature of the pipeline's outer wall. By analyzing the temperature gradient distribution at different clock positions in the axially adjacent region of the crack, the liquid level and flow state of the LNG within the pipeline can be indirectly inferred.

[0034] In this embodiment of the invention, the liquid level in the pipeline is determined based on the temperature change of the pipeline. The temperature of the pipeline is higher during non-unloading periods than during unloading periods. The liquid level in the pipeline can be determined by the temperature change and distribution around the pipeline, and the flow state in the pipeline can be judged.

[0035] Vibration sensors are indicated by solid red circles. As an optional solution, accelerometers are used as vibration sensors. The vibration sensors are installed on the outer wall of the pipe near the crack. The function of the vibration sensors is to measure pipe vibration data, and then convert the time-domain signal into a frequency-domain signal through a subsequent Fourier transform to obtain the vibration frequency and amplitude characteristics of the monitoring point. This information is used to analyze vibration frequency changes and assess vibration fatigue life.

[0036] The network transmission medium, as a communication module, includes, but is not limited to, routers, network cables, or optical fibers. It connects to the wired or wireless interface of the pipeline monitoring device and is responsible for encapsulating the pipeline status and early warning information of the LNG cryogenic pipeline processed by the monitoring device into network data packets. These packets are then transmitted to the display equipment in the central control room via a wireless network, facilitating timely responses from staff based on the monitoring and early warning information.

[0037] The display device is located remotely and receives data from a network transmission medium. It runs dedicated software or a monitoring interface to provide real-time visualization of pipeline status and early warning information (such as strain values, temperature distribution maps, vibration spectra, crack safety levels, and warning messages) using charts, curves, numbers, and color codes.

[0038] The cables are typically multi-core shielded cables used to connect sensors to pipeline monitoring devices to enable communication transmission of sensor data.

[0039] In this embodiment of the invention, multiple sensors are physically connected to the corresponding input ports of the pipeline monitoring device via cables. The data output terminal of the pipeline monitoring device is connected to a network transmission medium via wired or wireless means. The network transmission medium establishes a communication connection with a remote display device through a wireless network.

[0040] Furthermore, the system may also include: an explosion-proof protection device. The explosion-proof protection device is a protective housing or encapsulation structure designed to meet the explosion-proof safety requirements of the LNG environment. The explosion-proof protection device encapsulates the pipeline monitoring device and necessary electrical connections, ensuring they meet the specified explosion-proof rating and preventing potential electrical sparks from the internal circuitry from igniting the external explosive atmosphere.

[0041] This system achieves non-invasive, online, multi-parameter fusion monitoring of crack conditions on the inner surface of LNG cryogenic pipelines by coordinating multiple sensors on the outer wall and integrating data acquisition, analysis, and remote transmission functions. The system can simultaneously acquire and comprehensively analyze strain information reflecting crack propagation, temperature and liquid level information reflecting pipeline operating conditions, and vibration information reflecting structural dynamic loads, thereby improving the accuracy and reliability of crack propagation behavior assessment. Simultaneously, remote wireless transmission and visual display functions allow personnel to monitor the pipeline's safety status in real time without physically being present at high-risk sites, improving the convenience and safety of monitoring. The system's explosion-proof design ensures its applicability and safety in specific hazardous environments.

[0042] It is worth noting that, Figure 1 The pipeline monitoring system for cracks on the inner surface of LNG cryogenic pipelines shown is also applicable to Figure 2 or Figure 3 The pipeline monitoring methods for cracks on the inner surface of LNG cryogenic pipelines will not be elaborated here.

[0043] The following uses a pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline as an example to illustrate the implementation process of the pipeline monitoring method for cracks on the inner surface of an LNG cryogenic pipeline provided in this embodiment of the invention. It is understood that the executing entity of the pipeline monitoring method for cracks on the inner surface of an LNG cryogenic pipeline provided in this embodiment of the invention includes, but is not limited to, a pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline.

[0044] Figure 2 A flowchart of a pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines provided in an embodiment of the present invention is shown below. Figure 2 As shown, the method includes: Step 101: Based on the geometric characteristics of the cracks on the inner surface of the LNG cryogenic pipeline, various sensors are installed on the outer surface of the LNG cryogenic pipeline.

[0045] In this embodiment of the invention, various sensors include strain sensors, temperature sensors, and vibration sensors. Geometric features include, but are not limited to, crack length, depth, orientation, and position in the circumferential and axial directions of the pipe.

[0046] Specifically, strain sensors are placed in the projected area of ​​the outer surface corresponding to the geometric features of the inner surface crack and at key monitoring points (such as directly above the crack tip and stress concentration areas on both sides of the crack); temperature sensors are uniformly distributed circumferentially in the cross-section near the crack to capture temperature gradients; and vibration sensors are installed in the area near the crack. All sensors are fixed to the outer wall of the pipe using reliable processes (such as special adhesives and protection, clamps) to ensure the effectiveness and long-term stability of signal transmission.

[0047] This invention employs a targeted deployment strategy based on crack geometry, enabling external surface sensors to optimally detect the external response triggered by internal crack propagation, thus laying a physical foundation for accurate subsequent monitoring.

[0048] Step 102: Collect multi-source data through multiple sensors to generate pipeline strain observation values, temperature sensing data, and vibration sensing data.

[0049] In this embodiment of the invention, the multi-source data includes strain sensing data, temperature sensing data, and vibration sensing data. Specifically, multiple sensors are deployed simultaneously to collect multi-source data: strain sensors output strain sensing data, temperature sensors output temperature sensing data, and vibration sensors output vibration sensing data.

[0050] In this embodiment of the invention, the strain observation value of the pipeline is the difference between the strain sensing data collected by strain sensors at the crack tip position and the positions on both sides of the crack and the strain sensing data collected by strain sensors at a position a first length away from the crack.

[0051] This invention provides calibrated and reliable input data for subsequent comprehensive analysis by simultaneously acquiring multi-source data and generating strain observation values ​​based on strain sensing data.

[0052] Step 103: Monitor the pipeline condition of the LNG cryogenic pipeline based on pipeline strain observations, temperature sensing data, and strain benchmark values, and generate the pipeline crack fatigue life based on vibration sensing data.

[0053] In this embodiment of the invention, based on the geometric characteristics of the crack (such as depth and length) and the pipe material properties, a theoretical strain benchmark value at the corresponding sensor location under the crack state is obtained through theoretical calculation or experimental calibration. The real-time generated pipe strain observation values ​​are compared and analyzed with this strain benchmark value, and combined with simultaneous temperature sensing data (used to determine pipe operating conditions and liquid level status) and vibration sensing data (used to assess the crack fatigue life of the pipe) for comprehensive analysis. Based on the degree to which the observed values ​​deviate from the benchmark value and the consistency trend of the multi-source data, the pipe is determined to be in a normal state, an abnormal state, or a crack propagation state requiring early warning. The strain benchmark value is calculated based on geometric characteristics.

[0054] This invention significantly improves the accuracy and reliability of condition judgment by comparing real-time observation values ​​with theoretical benchmark values ​​and cross-validating them by integrating temperature and vibration sensing data. It effectively distinguishes crack propagation signals from other operating condition interferences, and achieves accurate and reliable online monitoring of pipeline safety status.

[0055] The technical solution provided in this invention utilizes the geometric characteristics of cracks on the inner surface of LNG cryogenic pipelines. Multiple sensors are installed on the outer surface of the pipeline. These sensors collect multi-source data, generating pipeline strain observations, temperature sensing data, and vibration sensing data. The pipeline condition is monitored based on the strain observations, temperature sensing data, and strain reference values. Furthermore, the crack fatigue life of the pipeline is generated based on the vibration sensing data. The strain reference value is calculated based on geometric characteristics. By deploying multiple types of sensors on the outer surface and fusing multi-source data such as strain, temperature, and vibration, non-invasive and highly reliable monitoring of the crack condition on the inner surface of the pipeline is achieved. This effectively distinguishes between real propagation signals and operational interference, improving the accuracy of condition assessment. Simultaneously, the sensor deployment and protection processes ensure long-term stable operation of the system in cryogenic environments prone to condensation, providing integrated technical support for pipeline safety early warning and life assessment.

[0056] Figure 3 A flowchart of another pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines provided by an embodiment of the present invention is shown below. Figure 3 As shown, the method includes: Step 201: Based on the geometric features, mark the crack geometry at the corresponding position on the outer surface.

[0057] In this embodiment of the invention, each step is performed by a pipeline monitoring device for cracks on the inner surface of LNG cryogenic pipelines.

[0058] In this embodiment of the invention, non-destructive testing equipment is used to locate the geometric features of cracks on the inner surface of LNG cryogenic pipelines. These geometric features include, but are not limited to, crack length, depth, orientation, and position in the circumferential and axial directions of the pipeline. Precise crack geometric markings are then made in the corresponding area on the outer surface of the pipeline. These markings indicate the external projection position of the internal crack, providing a spatial reference for subsequent sensor placement.

[0059] Step 202: Based on the crack geometry markings, set multiple strain sensors at the crack tip, both sides of the crack, and at a distance of the first length from the crack.

[0060] In this embodiment of the invention, the placement points of the strain sensors are determined based on the geometric markings of the crack. At least five strain sensors are deployed, typically at the outer surface position corresponding to the crack tip, and at stress-sensitive areas on both sides of the crack. One or more sensors are also placed at a certain distance (a first length, e.g., 500 mm) from the crack in an intact pipe area as reference points. The strain sensors at the crack tip and directly above the crack on both sides of the crack primarily measure strain data, while the strain data measured by the strain sensor at a distance of the first length (500 mm) from the crack is used for comparison.

[0061] Figure 4 This is a schematic diagram of a strain sensor adhesive protection method provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the arrangement for protecting each strain sensor includes: the strain sensor, a low-temperature protective film (PTFE film), low-temperature sealant, and a signal cable. The specific setup process includes: Step 2021: Remove the insulation layer of the LNG cryogenic pipeline according to the bonding area of ​​the strain sensor.

[0062] In this embodiment of the invention, the bonding area is the outer surface area of ​​the pipe where the strain sensor is planned to be bonded. Specifically, in the outer surface area of ​​the pipe where the strain sensor is planned to be bonded, the insulation layer is partially removed to expose the pipe body for subsequent operations.

[0063] It is worth noting that the pasting area can be set according to the size of the area required for construction and the size of the construction tools; this embodiment of the invention does not limit this. As an optional solution, the pasting area is 20cm × 20cm.

[0064] Step 2022: Perform gas purging and cleaning operations on the exposed pipeline body after dismantling.

[0065] In this embodiment of the invention, the exposed surface of the pipe body is purged with gas (such as air or nitrogen) to remove any condensation or moisture that may be present; once there is no condensation on the pipe surface, the pipe surface is polished to remove oil stains, protective paint and other materials, exposing the metallic luster, and then wiped and cleaned with alcohol cotton balls to ensure that the surface is clean, dry and free of oil stains, achieving ideal bonding conditions.

[0066] Step 2023: Attach the strain sensor to the corresponding cleaned area using a polytetrafluoroethylene (PTFE) membrane.

[0067] In this embodiment of the invention, the strain sensor is attached to the cleaned corresponding area using a polytetrafluoroethylene (PTFE) film as an intermediary layer. The PTFE film serves to isolate and initially fix the sensor.

[0068] In this embodiment of the invention, considering the fragility of the strain gauge and the accuracy of its placement, the exhaust pipe can be temporarily removed when attaching the strain gauge. The attachment time should not exceed the specified duration (30 seconds). After attaching the strain gauge, press it continuously with your thumb through a polytetrafluoroethylene (PTFE) membrane (the membrane should completely cover the strain gauge with a length margin of one kilometre). The pressing time is recommended to be 5 minutes. At the beginning of pressing, the area should be purged with the exhaust pipe. After pressing, use a multimeter to test the voltage of the strain gauge. If the test is normal, proceed to the next step.

[0069] Step 2024: Apply low-temperature resistant sealant along the edge of the polytetrafluoroethylene film to seal it.

[0070] In this embodiment of the invention, a low-temperature resistant sealant is used to coat and seal the edge of the polytetrafluoroethylene film to form a protective layer, thereby isolating the sensor and the bonding interface from the influence of the external environment (such as moisture and low temperature), and ensuring its long-term stability and signal reliability in low-temperature environments.

[0071] In this embodiment of the invention, sealing is performed from the center outwards to expel as much air as possible from under the membrane. After sealing, a blower is used to continue purging until the protective adhesive is completely cured. The strain gauges at each location are then attached and protected sequentially.

[0072] Step 2025: Initialize the state of the sealed strain sensor to complete the strain sensor setup.

[0073] In this embodiment of the invention, after the strain sensor is installed and sealed, it is powered on for inspection and initialization is performed to establish an accurate initial measurement reference and complete the setting of the strain sensor.

[0074] In this embodiment of the invention, the initialization operation includes pre-cooling the pipeline. After the pipeline is restored to its original cold state, before pre-cooling begins, the strain sensor is balanced and "zeroed" to record the strain changes during the cooling process of the pipeline.

[0075] Furthermore, each strain sensor was operated to record strain changes during pipeline operation.

[0076] This invention ensures the effective installation, signal quality, and long-term operational stability of strain sensors in the harsh surface environment of low-temperature pipelines through precise positioning, surface treatment, bonding process with a protective layer, and initialization, laying the foundation for obtaining reliable strain data.

[0077] Step 203: Based on the crack geometry, select multiple circumferential orientations at the second axial length position of the cross section where the crack is located, and set multiple temperature sensors at the selected circumferential orientations.

[0078] In this embodiment of the invention, based on the geometric markings of the crack, multiple circumferential orientations (such as the 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock directions of a simulated clock) are selected at a certain distance (second length, for example, 200 mm) from the cross-section where the crack is located along the axial direction of the pipe, and temperature sensors are arranged at these orientations.

[0079] As an alternative, two temperature sensors are placed at the location of the crack, and one sensor is placed at the other circumferential locations.

[0080] Figure 5 This is a schematic diagram of a temperature sensor adhesive protection method provided in an embodiment of the present invention, as shown below. Figure 5 As shown, the solid green circles represent temperature sensors. One temperature sensor is placed at the 12 o'clock, 3 o'clock, and 9 o'clock positions on the simulated clock face, and two temperature sensors are placed at the 6 o'clock position (where the crack is located). The specific setup process includes: Step 2031: Clean the LNG cryogenic pipeline.

[0081] In this embodiment of the invention, the outer surface area of ​​the pipe where the temperature sensor is planned to be installed is cleaned. The cleaning process is described in step 2022 and will not be repeated here.

[0082] Step 2032: Fix multiple temperature sensors to the outer surface of the LNG cryogenic pipeline using clamps.

[0083] As an alternative, temperature sensors are placed at the 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock positions on the cross section 20cm away from the crack in the pipe, and two sensors are placed at the location of the crack.

[0084] In this embodiment of the invention, clamps made of metal or composite materials are used to tightly fix each temperature sensor to a designated clean position on the outer surface of the pipe, ensuring that each temperature sensor is in close contact with the pipe surface, thereby achieving good thermal contact.

[0085] Furthermore, various temperature sensors were operated to record data on the changes in the outer surface temperature of the pipeline during pre-cooling and operation.

[0086] Step 204: Based on the crack geometry, set up multiple vibration sensors at the third axial length position of the cross section where the crack is located.

[0087] In this embodiment of the invention, a vibration sensor is installed at a certain distance (a third length, for example, 10-15 cm) from the cross-section where the crack is located along the axial direction of the pipe, based on the crack geometry markings.

[0088] Figure 6 This is a schematic diagram of a vibration sensor adhesive protection method provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the solid orange circles represent vibration sensors. One vibration sensor is placed 10-15 cm away from each side of the pipe crack. The specific setup process includes: Step 2041: Clean the LNG cryogenic pipeline.

[0089] In this embodiment of the invention, the outer surface area of ​​the pipe where the vibration sensor is planned to be installed is cleaned. The cleaning process is described in step 2022 and will not be repeated here.

[0090] Step 2042: Fix multiple vibration sensors to the outer surface of the LNG cryogenic pipeline using clamps.

[0091] In this embodiment of the invention, clamps made of metal or composite materials are used to firmly fix each vibration sensor to a designated clean position on the outer surface of the pipe, ensuring that each vibration sensor is in close contact with the pipe surface, thereby enabling accurate detection of pipe vibration.

[0092] This invention clearly defines the positioning logic and mechanical fixing method of the temperature and vibration sensor. The sensor is fixed with a clamp to ensure good contact between the sensor and the pipeline, thereby effectively collecting temperature distribution and vibration signals that reflect the pipeline's operating conditions.

[0093] Step 205: Generate pipeline strain observation values ​​based on the strain sensing data collected by strain sensors at the crack tip and both sides of the crack, and the strain sensing data collected by strain sensors at the first length distance from the crack.

[0094] Specifically, the strain sensing data collected by strain sensors (monitoring points) at the crack tip and both sides of the crack are compared with the strain sensing data collected by a strain sensor (comparison point) at a distance of the first length from the crack to calculate the difference between multiple pipeline strain observation values.

[0095] In this embodiment of the invention, the strain observation values ​​of the pipeline are used to characterize the relative deformation state of the crack region, mainly to eliminate common mode interference (such as overall temperature strain) and highlight the local strain changes related to the crack.

[0096] Step 206: Based on the strain benchmark value, determine whether the observed strain value of the pipeline is within the first fluctuation range. If it is within the first fluctuation range, proceed to step 207; if it is outside the first fluctuation range, proceed to step 208.

[0097] In this embodiment of the invention, the strain gauge is made of a special material with the same coefficient of thermal expansion as the pipe material. When the pipe experiences strain due to temperature, the strain sensor itself will also experience the same temperature effect. At this time, the strain caused by temperature change is offset. That is, the strain change caused by temperature change is compensated by the material of the strain gauge itself, so that the change only comes from the load on the pipe.

[0098] Based on experiments and simulations, the relationship between the maximum strain (strain reference value) on the pipe monitoring surface and the crack depth h (from the inner wall of the pipe to the deepest point of the crack) and crack length L when the internal pressure of the pipe is 0.5 MPa is as follows:

[0099] in, Here, L is the strain reference value, L is the crack length, and h is the crack depth.

[0100] It is worth noting that the above formula applies to: pipe diameter and wall thickness of 12.7 mm, crack depth h ranging from 0 to 12 mm, and crack length L ranging from 0 to 170 mm.

[0101] Specifically, determine whether the observed strain value of the pipeline is within the pre-set first fluctuation range (less than or equal to 10% of the strain reference value). If yes, it indicates that no abnormality has occurred in the pipeline, and continue to step 207; if no, it indicates that an abnormality has occurred in the pipeline, and further judgment is required, and continue to step 208.

[0102] Step 207: Confirm that the pipeline status is normal, then proceed to step 213.

[0103] In this embodiment of the invention, if the strain observation value is within the first fluctuation range, it is determined that the pipeline and crack are currently in a normal state, and monitoring continues, and step 213 is continued.

[0104] Step 208: Determine whether the LNG cryogenic pipeline is in operation based on the temperature sensor data. If it is in operation, proceed to step 209; if it is not in operation, proceed to step 212.

[0105] In this embodiment of the invention, historical temperature sensing data and corresponding liquid levels in the pipeline are recorded during the operation of the temperature sensor; based on the historical temperature sensing data and corresponding liquid levels in the pipeline, a pipeline temperature-liquid level distribution map is drawn.

[0106] Specifically, by matching the real-time liquid level in the pipeline with the real-time temperature sensor data collected in the pipeline, the real-time liquid level in the pipeline is determined; it is determined whether the real-time liquid level in the pipeline is greater than the preset liquid level threshold. If yes, it indicates that the pipeline is in operation and step 209 is continued; if no, it indicates that the pipeline is not in operation. This abnormal situation is caused by the abnormality of the sensor and monitoring equipment. The cause of the change needs to be determined on-site and step 212 is continued.

[0107] Step 209: Determine whether the observed strain value of the pipeline is within the second fluctuation range. If it is within the second fluctuation range, proceed to step 210; if it is outside the second fluctuation range, proceed to step 211.

[0108] Specifically, determine whether the observed strain value of the pipeline is within the pre-set second fluctuation range (greater than 10% of the strain reference value and less than or equal to 20% of the strain reference value). If yes, it indicates that the pipeline has abnormal parameters, and continue to execute step 210; if no, it indicates that the pipeline has abnormal crack propagation, and continue to execute step 211.

[0109] Step 210: Determine that the pipeline status is abnormal and issue a parameter warning, then continue to step 213.

[0110] In this embodiment of the invention, the abnormal parameter status indicates that a significant change has been detected but has not yet reached an emergency level. The system triggers a parameter warning, prompting the operator to pay attention to and reduce parameters such as pipeline flow rate and continue monitoring. If the abnormality persists within 24 hours, on-site inspection is required.

[0111] Step 211: Determine that the pipeline is in an abnormal crack propagation state and issue a crack propagation warning. Continue to step 213.

[0112] In this embodiment of the invention, if the observed strain value of the pipeline is outside the second fluctuation range, it indicates that the observed strain value is greater than 20% of the strain reference value, and the pipeline condition is determined to be abnormal crack propagation. The abnormal crack propagation state suggests that the crack may have propagated rapidly or significantly, triggering a higher-level crack propagation warning, indicating the need for immediate shutdown for on-site verification and maintenance measures.

[0113] This invention constructs a hierarchical, multi-condition triggered state judgment and early warning logic. By introducing a first fluctuation range for preliminary screening, and combining it with the pipeline operating status for secondary judgment, and finally using a second fluctuation range to distinguish the degree of anomaly, false alarms are effectively reduced, and the accuracy of identifying the risk of real crack propagation and the pertinence of early warning are improved.

[0114] Step 212: Determine that the pipeline status is abnormal due to sensor and monitoring equipment, issue equipment warning, and continue to step 213.

[0115] In this embodiment of the invention, if it is determined that the pipeline is in an inactive state, but the strain observation value is abnormal, it indicates that the sensor and monitoring equipment are abnormal. The abnormality of the sensor and monitoring equipment is caused by the failure of the monitoring system's own equipment (such as sensor or line fault), which triggers the equipment warning and prompts the monitoring equipment to be inspected and maintained.

[0116] Step 213: Generate pipeline vibration frequency parameters based on vibration sensing data according to the first time interval.

[0117] In this embodiment of the invention, vibration sensing data collected by the vibration sensor is extracted according to a set first time interval; the vibration sensing data is subjected to spectrum analysis by Fourier transform to extract the vibration frequency parameters of the pipeline at the monitoring point. The vibration frequency parameters include, but are not limited to, the fundamental frequency, the main harmonic frequencies and their amplitudes.

[0118] It is worth noting that the first time interval can be set according to actual needs, and this embodiment of the invention does not limit it. As an optional solution, the first time interval is six months.

[0119] Step 214: Based on the pre-established finite element model, perform load identification and stress analysis according to the vibration frequency parameters to generate stress amplitude.

[0120] In this embodiment of the invention, the finite element model is a dedicated computational model for load identification and stress analysis. As a transfer function or converter, it converts the measured vibration frequency parameters, which reflect the dynamic characteristics of the overall pipeline system, into the stress amplitude borne by the local area at the crack tip for fatigue assessment.

[0121] As an optional approach, the finite element model construction process of this invention is as follows: First, based on the actual geometric dimensions (diameter, wall thickness), material mechanical parameters (elastic modulus, Poisson's ratio, density) of the LNG cryogenic pipeline to be monitored, and the initial geometric characteristics (location, length, depth) of the internal surface cracks obtained through non-destructive testing, a three-dimensional geometric model of the pipeline, including simplified crack characterization, is established. Second, boundary conditions are set at the corresponding locations of the model according to the actual support and constraint conditions of the pipeline. Then, the model is meshed, and local refinement is performed in the crack region. Finally, by comparing the natural frequencies calculated by the model with the initial measured vibration frequencies of the pipeline, the boundary conditions or material parameters of the model are verified and fine-tuned to ensure that the dynamic characteristics of the model are consistent with the actual pipeline, thereby obtaining a finite element model that can be used to convert vibration frequency parameters into crack tip stress amplitude.

[0122] In this embodiment of the invention, a pre-established finite element model of the pipeline system is used, with vibration frequency parameters as load inputs or excitation conditions, for dynamic analysis. Through model calculations, the alternating stress level generated at critical crack locations (such as crack tips) under corresponding vibration loads is identified, and then the stress amplitude used for fatigue assessment is calculated.

[0123] This invention achieves a quantitative conversion from macroscopic, holistic vibration frequency parameters to microscopic, localized crack tip stress amplitudes by introducing and applying a specially constructed finite element analysis model. This conversion enables vibration data, originally used only for condition monitoring, to be used for quantitative life prediction based on fracture mechanics or fatigue theory, enhancing the depth of data utilization in monitoring systems, avoiding the difficulty of directly measuring local strain under complex working conditions, and providing an indirect but engineering-feasible stress assessment path.

[0124] Step 215: Match the crack fatigue life of the pipeline corresponding to the stress amplitude using the preset stress-life curve (SN curve).

[0125] In this embodiment of the invention, based on the fatigue characteristics of the pipeline material and referring to its SN curve, the calculated stress amplitude is matched with the curve to estimate the estimated crack fatigue life of the pipeline (or crack) under the cyclic action of the stress amplitude, that is, the number of cycles or equivalent operating time required to reach fatigue failure.

[0126] This invention transforms vibration monitoring data into a quantitative assessment of structural fatigue life. Through spectrum analysis, finite element load identification, and SN curve matching, it establishes a technological chain from vibration phenomena to remaining life prediction, providing crucial data support for preventative maintenance and life management of pipelines.

[0127] Step 216: Remeasure and update the geometric characteristics of the inner surface cracks of the LNG cryogenic pipeline according to the second time interval.

[0128] In this embodiment of the invention, the geometric characteristics (such as depth and length) of the cracks on the inner surface of the pipe are remeasured using a non-destructive testing method during shutdown and maintenance according to a second time interval.

[0129] It is worth noting that the second time interval can be set according to actual needs, and this embodiment of the invention does not limit it. As an optional solution, the second time interval is one year.

[0130] Step 217: Based on geometric features, recalculate and update the strain reference values.

[0131] In this embodiment of the invention, based on the updated crack geometry, the relationship from step 206 is applied to recalculate and update the strain benchmark value used for state judgment, so that the judgment benchmark of the monitoring system keeps synchronized with the actual crack development state, ensuring the accuracy of long-term monitoring.

[0132] This invention establishes a self-updating and calibration mechanism for the monitoring system. By periodically updating the crack geometry and the corresponding strain reference value, the system can adapt to possible changes in the crack, avoid judgment distortion due to the use of outdated references, and ensure the effectiveness and reliability of long-term online monitoring.

[0133] It is worth noting that the acquisition, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. The user information in the embodiments of this application was obtained through legal and compliant means, and the acquisition, storage, use, and processing of user information have been authorized and agreed upon by the client.

[0134] It is worth noting that the information collected in this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data all comply with the relevant laws, regulations and standards of the relevant countries and regions, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding operation portals are provided for users to choose to authorize or refuse.

[0135] It is worth noting that the technical solution provided in this application provides users with a corresponding operation entry point, allowing users to choose to agree to or reject the automated decision-making result; if the user chooses to reject, the process will proceed to the expert decision-making process.

[0136] The technical solution of the pipeline monitoring method for internal surface cracks in LNG cryogenic pipelines provided in this invention involves setting multiple sensors on the outer surface of the LNG cryogenic pipeline based on the geometric characteristics of the internal surface cracks. Multiple sensors collect multi-source data to generate pipeline strain observation values, temperature sensing data, and vibration sensing data. The pipeline condition is monitored based on the strain observation values, temperature sensing data, and strain reference values. Based on the vibration sensing data, the pipeline's crack fatigue life is generated. The strain reference value is calculated based on geometric characteristics. By deploying multiple types of sensors on the outer surface and fusing multi-source data such as strain, temperature, and vibration, non-invasive and highly reliable monitoring of the internal surface crack condition is achieved. This effectively distinguishes between real propagation signals and operational interference, improving the accuracy of condition judgment. Simultaneously, the sensor deployment and protection processes ensure long-term stable operation of the system in cryogenic environments prone to condensation, providing integrated technical support for pipeline safety early warning and life assessment.

[0137] Figure 7 This is a schematic diagram of a pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline, provided in an embodiment of the present invention. This device is used to perform the aforementioned pipeline monitoring method for cracks on the inner surface of an LNG cryogenic pipeline. Figure 7 As shown, the device includes: a sensor setting unit 11, a data generation unit 12, and a pipeline condition monitoring unit 13.

[0138] The sensor setting unit 11 is used to set various sensors on the outer surface of the LNG cryogenic pipeline based on the geometric features of the cracks on the inner surface of the pipeline.

[0139] The data generation unit 12 is used to collect multi-source data through multiple sensors and generate pipeline strain observation values, temperature sensing data and vibration sensing data.

[0140] The pipeline condition monitoring unit 13 is used to monitor the pipeline condition of the LNG cryogenic pipeline based on the pipeline strain observation value, temperature sensing data and strain reference value, and to generate the crack fatigue life of the pipeline based on the vibration sensing data. The strain reference value is calculated based on geometric features.

[0141] In this embodiment of the invention, the sensor setting unit 11 is specifically used to mark crack geometry at corresponding positions on the outer surface according to geometric features; to set multiple strain sensors at the crack tip, both sides of the crack, and a position at a first length distance from the crack according to the crack geometry; to select multiple circumferential orientations at a second axial length distance from the cross-section where the crack is located according to the crack geometry, and to set multiple temperature sensors at the selected circumferential orientations; and to set multiple vibration sensors at a third axial length distance from the cross-section where the crack is located according to the crack geometry.

[0142] In this embodiment of the invention, the sensor setting unit 11 is specifically used to remove the insulation layer of the LNG cryogenic pipeline according to the pasting area of ​​the strain sensor; perform gas purging and cleaning operations on the exposed pipeline body after removal; paste the strain sensor to the corresponding area after cleaning using a polytetrafluoroethylene (PTFE) film; apply low-temperature resistant sealant along the edge of the PTFE film for sealing; initialize the state of the sealed strain sensor, and complete the setting of the strain sensor.

[0143] In this embodiment of the invention, the sensor setting unit 11 is specifically used to perform cleaning operations on the LNG cryogenic pipeline; multiple temperature sensors are fixed to the outer surface of the LNG cryogenic pipeline by clamps.

[0144] In this embodiment of the invention, the sensor setting unit 11 is specifically used to perform cleaning operations on the LNG cryogenic pipeline; multiple vibration sensors are fixed to the outer surface of the LNG cryogenic pipeline by clamps.

[0145] In this embodiment of the invention, the multi-source data includes strain sensing data; the data generation unit 12 is specifically used to generate pipeline strain observation values ​​based on the strain sensing data collected by strain sensors at the crack tip position and both sides of the crack position and the strain sensing data collected by strain sensors at a position a first length away from the crack.

[0146] In this embodiment of the invention, the pipeline condition monitoring unit 13 is specifically used to determine whether the pipeline strain observation value is within a first fluctuation range based on the strain reference value; if it is within the first fluctuation range, the pipeline condition is determined to be normal; if it is outside the first fluctuation range, the LNG cryogenic pipeline is determined to be in operation based on temperature sensing data; if it is in operation, the pipeline strain observation value is determined to be within a second fluctuation range; if it is within the second fluctuation range, the pipeline condition is determined to be abnormal, and a parameter warning is issued; if it is outside the second fluctuation range, the pipeline condition is determined to be abnormal crack propagation, and a crack propagation warning is issued; if it is not in operation, the pipeline condition is determined to be abnormal sensor and monitoring equipment, and an equipment warning is issued.

[0147] In this embodiment of the invention, the device further includes: a vibration frequency parameter generation unit 14, a stress amplitude analysis unit 15, and a life prediction unit 16.

[0148] The vibration frequency parameter generation unit 14 is used to generate pipeline vibration frequency parameters based on vibration sensing data according to a first time interval.

[0149] The stress amplitude analysis unit 15 is used to identify loads and perform stress analysis based on the pre-established finite element model and vibration frequency parameters to generate stress amplitudes.

[0150] The life prediction unit 16 is used to match the crack fatigue life of the pipeline corresponding to the stress amplitude through a preset stress life curve.

[0151] In this embodiment of the invention, the device further includes a geometric feature update unit 17 and a reference value update unit 18.

[0152] The geometric feature update unit 17 is used to remeasure and update the geometric features of the inner surface cracks of the LNG cryogenic pipeline according to the second time interval.

[0153] The reference value update unit 18 is used to recalculate and update the strain reference value based on geometric features.

[0154] In this invention, based on the geometric characteristics of cracks on the inner surface of an LNG cryogenic pipeline, multiple sensors are installed on the outer surface of the pipeline. These sensors collect multi-source data to generate pipeline strain observations, temperature sensing data, and vibration sensing data. The pipeline condition is monitored based on the strain observations, temperature sensing data, and strain reference values. Furthermore, the crack fatigue life of the pipeline is generated based on the vibration sensing data. The strain reference value is calculated based on geometric characteristics. By deploying multiple types of sensors on the outer surface and fusing multi-source data such as strain, temperature, and vibration, non-invasive and highly reliable monitoring of the crack condition on the inner surface of the pipeline is achieved. This effectively distinguishes between real propagation signals and operational interference, improving the accuracy of condition assessment. Simultaneously, the sensor deployment and protection processes employed ensure long-term stable operation of the system in cryogenic environments prone to condensation, providing integrated technical support for pipeline safety early warning and life assessment.

[0155] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer device, specifically, a computer device can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0156] This invention provides a computer device, including a memory and a processor. The memory stores information including program instructions, and the processor controls the execution of the program instructions. When the program instructions are loaded and executed by the processor, they implement the steps of the above-described pipeline monitoring method for cracks on the inner surface of LNG cryogenic pipelines. For a detailed description, please refer to the above-described pipeline monitoring method for cracks on the inner surface of LNG cryogenic pipelines.

[0157] The following is for reference. Figure 8It shows a schematic diagram of the structure of a computer device 600 suitable for implementing the embodiments of this application.

[0158] like Figure 8 As shown, the computer device 600 includes a central processing unit (CPU) 601, which can perform various appropriate tasks and processes based on programs stored in read-only memory (ROM) 602 or programs loaded from storage section 608 into random access memory (RAM) 603. The RAM 603 also stores various programs and data required for the operation of the computer device 600. The CPU 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0159] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal feedback (LCD), etc., and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed in storage section 608 as needed.

[0160] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program including program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 609, and / or installed from removable medium 611.

[0161] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0162] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0163] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0164] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0165] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0166] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0167] The acquisition, storage, use, and processing of data in this application all comply with the relevant provisions of national laws and regulations.

[0168] It should be noted that in the embodiments of this application, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, it does not mean that the applicant has used or necessarily used the solution.

[0169] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0170] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0171] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0172] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for monitoring cracks on the inner surface of an LNG cryogenic pipeline, characterized in that, The method includes: Based on the geometric characteristics of the cracks on the inner surface of the LNG cryogenic pipeline, a variety of sensors are installed on the outer surface of the LNG cryogenic pipeline. Multi-source data is collected by multiple sensors to generate pipeline strain observation values, temperature sensing data and vibration sensing data; The pipeline condition of the LNG cryogenic pipeline is monitored based on the pipeline strain observations, temperature sensing data, and strain reference values. Based on the vibration sensing data, the crack fatigue life of the pipeline is generated. The strain reference values ​​are calculated based on the geometric features.

2. The pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines according to claim 1, characterized in that, Based on the geometric characteristics of the cracks on the inner surface of the LNG cryogenic pipeline, various sensors are installed on the outer surface of the LNG cryogenic pipeline, including: Based on the aforementioned geometric features, crack geometric markings are made at corresponding positions on the outer surface; Based on the crack geometry markings, multiple strain sensors are set at the crack tip, both sides of the crack, and at a position at a distance of the first length from the crack. Based on the crack geometric markings, multiple circumferential orientations are selected at a position with a distance of the second axial length from the cross section where the crack is located, and multiple temperature sensors are set at the selected circumferential orientations. Based on the crack geometry markings, multiple vibration sensors are installed at a position three axial lengths away from the cross-section where the crack is located.

3. The pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines according to claim 2, characterized in that, The configuration of multiple strain sensors includes: Remove the insulation layer of the LNG cryogenic pipeline according to the bonding area of ​​the strain sensor; The exposed pipeline body after dismantling was purged with gas and cleaned. The strain sensor is attached to the cleaned area using a polytetrafluoroethylene (PTFE) membrane. Apply a low-temperature resistant sealant along the edge of the polytetrafluoroethylene film to seal it. The state of the sealed strain sensor is initialized to complete the setting of the strain sensor.

4. The pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines according to claim 2, characterized in that, The configuration includes multiple temperature sensors, including: The LNG cryogenic pipeline was cleaned. Multiple temperature sensors are fixed to the outer surface of the LNG cryogenic pipeline using clamps; The configuration of multiple vibration sensors includes: The LNG cryogenic pipeline was cleaned. Multiple vibration sensors are fixed to the outer surface of the LNG cryogenic pipeline using clamps.

5. The pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines according to claim 1, characterized in that, The monitoring of the LNG cryogenic pipeline's condition based on the observed pipeline strain values, temperature sensing data, and strain reference values ​​includes: Based on the strain reference value, determine whether the observed strain value of the pipeline is within the first fluctuation range; If it is within the first fluctuation range, the pipeline status is determined to be normal; If the temperature is outside the first fluctuation range, determine whether the LNG cryogenic pipeline is in operation based on the temperature sensing data. If the pipeline is in operation, determine whether the observed strain value is within the second fluctuation range; If the pipeline is within the second fluctuation range, its status is determined to be abnormal, and a parameter warning is issued. If the pipe is outside the second fluctuation range, the pipe condition is determined to be abnormal crack propagation, and a crack propagation warning is issued. If the pipeline is not in operation, the status of the sensors and monitoring equipment is determined to be abnormal, and an equipment warning is issued.

6. The pipeline monitoring method for inner surface cracks in LNG cryogenic pipelines according to claim 1, characterized in that, The step of generating the crack fatigue life of the pipeline based on the vibration sensing data includes: According to the vibration sensing data, the pipeline vibration frequency parameters are generated according to the first time interval. Based on the pre-established finite element model, load identification and stress analysis are performed according to the vibration frequency parameters to generate stress amplitude. By using a preset stress-life curve, the crack fatigue life of the pipeline corresponding to the stress amplitude is determined.

7. A pipeline monitoring device for cracks on the inner surface of an LNG cryogenic pipeline, characterized in that, The device includes: A sensor setting unit is used to set multiple sensors on the outer surface of the LNG cryogenic pipeline based on the geometric characteristics of cracks on the inner surface of the pipeline. The data generation unit is used to collect multi-source data through multiple sensors and generate pipeline strain observation values, temperature sensing data, and vibration sensing data; The pipeline condition monitoring unit is used to monitor the pipeline condition of the LNG cryogenic pipeline based on the pipeline strain observation values, temperature sensing data and strain reference values, and to generate the crack fatigue life of the pipeline based on the vibration sensing data. The strain reference values ​​are calculated based on the geometric features.

8. A pipeline monitoring system for cracks on the inner surface of an LNG cryogenic pipeline, characterized in that, The system includes: an LNG cryogenic pipeline, multiple sensors, the pipeline monitoring device as described in claim 7, a network transmission medium, and a display device; The inner surface of the LNG cryogenic pipeline has cracks, and the outer surface is equipped with various sensors. The pipeline monitoring device is connected to various sensors on the outer surface of the LNG cryogenic pipeline via cables. The network transmission medium is communicatively connected to the pipeline monitoring device, and the pipeline monitoring device wirelessly transmits the pipeline status of the LNG cryogenic pipeline to the display device through the network transmission medium; The display device provides a visual representation of the LNG cryogenic pipeline's status.

9. A computer-readable medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the pipeline monitoring method for cracks on the inner surface of LNG cryogenic pipelines as described in any one of claims 1 to 6.

10. A computer device comprising a memory and a processor, the memory for storing information including program instructions, and the processor for controlling the execution of the program instructions, characterized in that, When the program instructions are loaded and executed by the processor, the pipeline monitoring method for cracks on the inner surface of an LNG cryogenic pipeline as described in any one of claims 1 to 6 is implemented.

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