Method and device for evaluating integrity of medium-low pressure pure hydrogen / hydrogen-doped gas pipeline

Abstract

The application provides a kind of low-pressure pure hydrogen / hydrogen-doped gas pipeline integrity evaluation method and device, including data acquisition, defect classification, macro mechanics test, finite element calculation, evaluation criterion correction, defect-containing pure hydrogen / hydrogen-doped gas pipeline integrity evaluation, defect-containing pure hydrogen / hydrogen-doped pipeline comprehensive evaluation seven links, the application has the advantages of systematization, operability, can fully consider the influence of low-pressure gas pipeline pure hydrogen / hydrogen-doped transmission on pipeline defect evaluation and the change of pipeline residual strength, is beneficial to the implementation of low-pressure pure hydrogen / hydrogen-doped gas pipeline integrity evaluation process.

Description

Technical Field

[0001] This invention relates to the field of pipeline management technology, and in particular to a method and apparatus for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines. Background Technology

[0002] my country's hydrogen energy industry is currently experiencing rapid development, with increasing demand for hydrogen in urban areas. There is an urgent need to accelerate the green energy transition, promote the development of the hydrogen energy industry, and utilize medium- and low-pressure pure hydrogen or hydrogen-blended gas for large-scale application in residential settings. Safety issues related to pure hydrogen / hydrogen-blended gas pipelines are crucial throughout the entire lifecycle of gas pipeline design, construction, operation, and maintenance.

[0003] However, due to the low density and high flammability and explosiveness of hydrogen, the safe transportation of hydrogen through pipelines has become an internationally recognized technical challenge. Simultaneously, given hydrogen's high density and zero emissions, the large-scale application of medium- and low-pressure pure hydrogen or hydrogen-blended gas in residential applications urgently requires overcoming technical difficulties related to inherent safety, transportation processes, and key equipment. Currently, the methods for evaluating the integrity of gas pipelines are relatively systematic; however, the impact of hydrogen blending or pure hydrogen transportation on pipeline defect assessment and changes in pipeline residual strength are not considered, resulting in certain limitations and an inability to comprehensively and systematically assess the integrity of pure hydrogen / hydrogen-blended pipelines during operation. On the one hand, existing research mainly focuses on obtaining material stress-strain curves through small-size hydrogen-blended sample tests under hydrogen-blended gas pipeline transportation conditions, as well as the fracture toughness of materials under different hydrogen blending ratios, to investigate the impact of hydrogen blending on the hydrogen embrittlement behavior of materials. This only considers the impact of hydrogen blending on material properties and lacks exploration of the impact of hydrogen blending on defect assessment and the residual strength of pipelines with defects after hydrogen blending. On the other hand, existing integrity assessment methods are designed for conventional oil or gas pipelines. These methods do not consider the impact of hydrogen on the safety assessment of defective pipelines, and the applicability of their safety assessment criteria to pure hydrogen / hydrogen-blended gas pipelines is unclear. The corresponding assessment criteria need to be adjusted according to hydrogen blending conditions. Therefore, establishing a method and system for evaluating the integrity of pure hydrogen / hydrogen-blended gas pipelines, based on traditional pipeline integrity assessment methods and considering the impact of hydrogen transportation on pipeline defect assessment and changes in residual strength, is of great significance for the safety of pure hydrogen / hydrogen-blended gas transportation. Summary of the Invention

[0004] The present invention aims to provide a method and apparatus for evaluating the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines that overcomes or at least partially solves the above-mentioned problems.

[0005] To achieve the above objectives, the technical solution of the present invention is specifically implemented as follows:

[0006] One aspect of the present invention provides a method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines, comprising:

[0007] Collect basic pipeline information and pipeline defect information;

[0008] Based on the pipeline basic information and the pipeline defect information, defects are classified into volumetric defects, crack defects, and dents.

[0009] Macroscopic mechanical tests are performed on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters, wherein the tests include: slow strain rate tensile test and fracture toughness test;

[0010] Establish a finite element model of the pipeline and calculate the stress distribution state of the pipeline during actual operation;

[0011] Revise the safety assessment criteria for each defect;

[0012] Integrity assessment of pure hydrogen / hydrogen-blended gas pipelines is conducted based on the revised defect safety assessment criteria.

[0013] A comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines was conducted.

[0014] Optionally, the pipeline basic information includes: material, operating pressure, temperature, medium, and hydrogen doping ratio;

[0015] The pipeline defect information includes: shape, location, and size.

[0016] Optionally, the volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects;

[0017] The crack-type defects include: surface cracks, buried cracks, and penetrating cracks;

[0018] Indentation includes localized elastoplastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface profile.

[0019] Optionally, the macroscopic mechanical testing of the pipeline environment to obtain yield strength, tensile strength, and fracture toughness parameters includes:

[0020] Slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments;

[0021] Slow strain rate tensile tests and fracture toughness tests in inert media environments;

[0022] The yield strength, tensile strength, fracture toughness, yield strength, and tensile strength of the material in a pure hydrogen / hydrogen-doped environment, as well as the yield strength and tensile strength of the material in an inert gas environment, were obtained.

[0023] Optionally, establishing a finite element model of the pipeline and calculating the stress distribution state of the pipeline during actual operation includes:

[0024] Based on the operating conditions, pressure, hydrogen doping ratio, temperature, and additional load conditions of pure hydrogen / hydrogen-blended pipelines in actual service, a finite element model is established to calculate the stress distribution of the pipeline during actual operation.

[0025] Optionally, the safety assessment criteria for correcting each defect include:

[0026] Based on the macroscopic mechanical performance test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators for different defect types are corrected for pure hydrogen / hydrogen-doped environment.

[0027] The safety assessment index corrections include: corrections to the safety assessment indexes for volumetric defects, corrections to the safety assessment indexes for crack-type defects, and corrections to the safety assessment indexes for dents.

[0028] in:

[0029] The correction of the volumetric defect safety assessment index includes: pure hydrogen / hydrogen-doped correction of the rheological stress involved in the evaluation process based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; in the process of determining the ultimate load, pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate internal pressure of the defective pipeline under pure internal pressure and pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate bending moment of the defective pipeline under pure bending moment.

[0030] The correction of the safety assessment index for crack-type defects includes: correcting the failure assessment diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments;

[0031] The correction of the indentation safety assessment index includes: correcting the evaluation critical diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment.

[0032] Optionally, the integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines based on the modified defect safety assessment criteria includes:

[0033] Based on the defect type, and combining the collected pipeline foundation information, pipeline defect information, and finite element analysis results, the safety of each defect is evaluated according to the revised safety assessment indicators.

[0034] Optionally, the comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines includes:

[0035] Based on the pipeline defect information and the comprehensive safety evaluation results of various defects, a comprehensive evaluation of the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines is made.

[0036] Another aspect of the present invention provides an integrity evaluation device for medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines, comprising:

[0037] The data acquisition module is used to collect basic pipeline information and pipeline defect information;

[0038] The classification module is used to classify defects based on the pipeline basic information and the pipeline defect information, and to classify defects into volume defects, crack defects and dents;

[0039] The testing module is used to perform macroscopic mechanical tests on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters. The tests include: slow strain rate tensile test and fracture toughness test.

[0040] The calculation module is used to build a finite element model of the pipeline and calculate the stress distribution of the pipeline during actual operation.

[0041] The correction module is used to correct the safety assessment criteria for various defects.

[0042] The first evaluation module is used to evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines based on the safety assessment criteria for the corrected defects.

[0043] The second evaluation module is used to conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects.

[0044] Optionally, the pipeline basic information includes: material, operating pressure, temperature, medium, and hydrogen doping ratio;

[0045] The pipeline defect information includes: shape, location, and size;

[0046] The volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects;

[0047] The crack-type defects include: surface cracks, buried cracks, and penetrating cracks;

[0048] Indentation includes localized elastoplastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface profile.

[0049] Therefore, the method and apparatus for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided by this invention, comprising seven steps—data acquisition, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects, and comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects—has the advantages of being systematic and operable. It can fully consider the impact of pure hydrogen / hydrogen-blended gas pipeline transportation on pipeline defect assessment and changes in pipeline residual strength, which is beneficial to the implementation of the integrity evaluation process for medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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.

[0051] Figure 1 A flowchart of the method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided in this embodiment of the invention;

[0052] Figure 2 This is a flowchart illustrating the method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided in an embodiment of the present invention.

[0053] Figure 3 This is a schematic diagram of the structure of the medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided in an embodiment of the present invention. Detailed Implementation

[0054] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0055] The purpose of this invention is to consider the impact of pure hydrogen / hydrogen-blended gas pipeline transportation on pipeline defect assessment and the changes in pipeline residual strength, and to establish a method and apparatus for evaluating the integrity of pure hydrogen / hydrogen-blended gas pipelines in medium and low pressure.

[0056] To address the aforementioned problems, this invention provides a method and apparatus for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines. The method comprises seven stages: data acquisition, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of defective pure hydrogen / hydrogen-blended gas pipelines, and comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines. This invention offers the advantages of being systematic and operable, fully considering the impact of pure hydrogen / hydrogen-blended gas transportation on pipeline defect assessment and changes in pipeline residual strength, thus facilitating the implementation of the integrity evaluation process for medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines.

[0057] Figure 1 A flowchart of the method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided in an embodiment of the present invention is shown. Figure 2 This diagram illustrates a flow chart of the method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided in an embodiment of the present invention. (See also...) Figure 1 and Figure 2 The method for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided in this embodiment of the invention includes:

[0058] S1 collects basic pipeline information and pipeline defect information.

[0059] The basic information of the pipeline includes: material, operating pressure, temperature, medium and hydrogen doping ratio; the pipeline defect information includes: shape, location and size.

[0060] Specifically, the data acquisition phase refers to collecting relevant data to support the integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines. This includes basic pipeline information such as material, operating pressure, temperature, medium, and hydrogen blending ratio, as well as pipeline defect information obtained through internal inspection and non-destructive testing methods. The data acquisition section can be integrated with other pipeline monitoring systems to read relevant pipeline monitoring data in real time and identify and classify it according to the data content and format required by this system, thus providing the foundational data for subsequent integrity evaluation.

[0061] S2, classify defects according to the pipeline basic information and the pipeline defect information, and classify defects into volume defects, crack defects and dents.

[0062] The volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects; the crack defects include: surface cracks, buried cracks, and penetrating cracks; the depressions include: localized elastoplastic deformations where the curvature of the pipe surface is significantly lower than the pipe surface profile.

[0063] Specifically, the defect classification process refers to classifying defects detected in pure hydrogen / hydrogen-blended gas pipelines into three main categories—volume defects, crack defects, and dents—based on pipeline defect information obtained through methods such as internal inspection and non-destructive testing. Volume defects include pipe corrosion, surface metal loss, and manufacturing defects; crack defects include surface cracks, buried cracks, and penetrating cracks; and dents include localized elastoplastic deformations caused by external impacts or compression during construction or operation, where the pipe surface curvature is significantly lower than the pipe surface contour.

[0064] S3. Perform macroscopic mechanical tests on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters. The tests include: slow strain rate tensile test and fracture toughness test.

[0065] The macroscopic mechanical tests performed on the pipeline environment to obtain yield strength, tensile strength, and fracture toughness parameters include: slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments; slow strain rate tensile tests and fracture toughness tests in inert medium environments; obtaining the yield strength, tensile strength, and fracture toughness of the material in pure hydrogen / hydrogen-doped environments, the yield strength in inert gas environments, and the tensile strength of the material in inert gas environments.

[0066] Specifically, the macroscopic mechanical testing includes slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments, as well as corresponding tests in an inert medium environment as a control. The macroscopic mechanical tests aim to obtain the corresponding yield strength, tensile strength, and fracture toughness parameters.

[0067] σ yH — Yield strength of materials in pure hydrogen / hydrogen-doped environments;

[0068] σ uH —Tensile strength of materials in pure hydrogen / hydrogen-doped environments;

[0069] K δH — Fracture toughness of materials in pure hydrogen / hydrogen-doped environments;

[0070] σ y — Yield strength of materials in an inert gas environment;

[0071] σ u — Yield strength of materials in an inert gas environment;

[0072] K δ —Tensile strength of materials in an inert gas environment.

[0073] S4. Establish a finite element model of the pipeline and calculate the stress distribution of the pipeline during actual operation.

[0074] The establishment of the pipeline finite element model and the calculation of the stress distribution state of the pipeline during actual operation include: based on the operating conditions, pressure, hydrogen doping ratio, temperature and additional load conditions of the pure hydrogen / hydrogen-doped pipeline in actual service conditions, the stress distribution state of the pipeline during actual operation is calculated by establishing a finite element model.

[0075] Specifically, the pipeline finite element analysis step refers to calculating the stress distribution of the pipeline during actual operation by using finite element modeling, based on the operating conditions, pressure, hydrogen blending ratio, temperature, and additional load conditions of the natural gas pure hydrogen / hydrogen-blended pipeline under actual service conditions.

[0076] S5, corrects the safety assessment criteria for each defect.

[0077] The safety assessment criteria for correcting various defects include: based on the macroscopic mechanical property test results in pure hydrogen / hydrogen-doped environments and inert environments, respectively, pure hydrogen / hydrogen-doped safety assessment indicators are corrected for different defect types; the correction of safety assessment indicators includes: correction of safety assessment indicators for volumetric defects, correction of safety assessment indicators for crack-type defects, and correction of safety assessment indicators for dents; wherein: the correction of safety assessment indicators for volumetric defects includes: based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments, the rheological stress involved in the evaluation process is... Pure hydrogen / hydrogen-doped correction; during the determination of ultimate load, the dimensionless plastic ultimate internal pressure of the defective pipeline under pure internal pressure is corrected using pure hydrogen / hydrogen-doped correction, and the dimensionless plastic ultimate bending moment of the defective pipeline under pure bending moment is corrected using pure hydrogen / hydrogen-doped correction; the correction of the safety assessment index for crack-type defects includes: correcting the failure assessment diagram based on the macroscopic mechanical properties under pure hydrogen / hydrogen-doped and inert environments; the correction of the safety assessment index for indentation includes: correcting the evaluation critical diagram based on the macroscopic mechanical properties under pure hydrogen / hydrogen-doped and inert environments.

[0078] Specifically, the evaluation criterion correction step refers to the pure hydrogen / hydrogen-doped hydrogen correction of safety assessment indicators for different defect types based on the macroscopic mechanical performance test results in pure hydrogen / hydrogen-doped hydrogen environments and inert environments.

[0079] Among them, the safety assessment index correction includes the correction of the safety assessment index for volumetric defects, the correction of the safety assessment index for crack defects, and the correction of the safety assessment index for dents.

[0080] The correction of the safety assessment index for volumetric defects refers to the adjustment of the rheological stress involved in the evaluation process based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments. Pure hydrogen / hydrogen-doped correction In the process of determining the ultimate load, the dimensionless plastic ultimate internal pressure p of a defective pipeline under pure internal pressure is considered. LS Perform pure hydrogen / hydrogen-doped correction p LSH The dimensionless plastic limit bending moment (m) of a defective pipeline under pure bending moment. LS Perform pure hydrogen / hydrogen-doped correction m LSH .

[0081] The correction of safety assessment index for crack-type defects refers to the modification of the failure assessment diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments.

[0082] The correction of the dent safety assessment index refers to the correction of the evaluation critical diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments.

[0083] S6, conduct an integrity assessment of pure hydrogen / hydrogen-blended gas pipelines based on the revised defect safety assessment criteria.

[0084] The integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines based on the modified defect safety assessment criteria includes: evaluating the safety of each defect according to the defect type, combined with the collected pipeline basic information, pipeline defect information, and finite element analysis results, based on the modified safety assessment indicators.

[0085] Specifically, the integrity evaluation of defective pure hydrogen / hydrogen-blended gas pipelines refers to conducting safety evaluations on pipelines containing the aforementioned defects based on the aforementioned defect types, combined with collected pipeline data, defect data, finite element analysis results, etc., and according to the revised safety assessment indicators.

[0086] S7 provides a comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines.

[0087] The comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines includes: based on the pipeline defect information, combining the safety evaluation results of various defects, and making a comprehensive evaluation of the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines.

[0088] Specifically, the comprehensive evaluation of defective pure hydrogen / hydrogen-blended pipelines refers to making a comprehensive evaluation of the integrity of medium and low-pressure pure hydrogen / hydrogen-blended gas pipelines based on the defect information of pure hydrogen / hydrogen-blended gas pipelines obtained from pipeline internal inspection and non-destructive testing, and by integrating the safety evaluation results of various defects.

[0089] The following example demonstrates a medium-pressure pure hydrogen gas pipeline with a maximum operating pressure of 4 MPa, a hydrogen blending ratio of 30%, and L245 pipeline steel.

[0090] Step 1, data acquisition, includes pipeline basic information and pipeline defect information. In this embodiment:

[0091] The basic information for the pipeline section includes: pipe diameter D = 406.4 mm, wall thickness t = 9.5 mm, material L245 pipeline steel, design pressure P = 4 MPa, service temperature is ambient temperature, the transported medium is hydrogen-blended natural gas, and the hydrogen blending ratio is 30%. The uniform thinning loss is 0.4 mm, and the future corrosion allowance (FCA) is 0.1 mm.

[0092] Pipeline defect information obtained through internal inspection, non-destructive testing, and other methods includes:

[0093] Defect 1 – Abnormal tube manufacturing: depth 23%, length 11mm, width 32mm.

[0094] Defect 2 - Depression: Maximum depression depth ddp = 15mm, depression radius rd = 26mm, length 25mm, width 48mm, distance from defect to weld Lw = 1524mm, distance from defect to discontinuity of main pipeline Lmsd = 2.2m.

[0095] Defect 3——

[0096] Step Two: Defect Classification. Based on the data collection results from Step One, defects are classified, where defect 1 is a volumetric defect, defect 2 is a dent, defect 3 is... Let's take defect 1 as an example:

[0097] Defect 1, a volumetric defect, is processed by regularizing its dimensions to achieve dimensionless representation as follows:

[0098] Relative axial length:

[0099] Relative circumferential length:

[0100] Relative depth: c = 0.23

[0101] Step 3: Macroscopic Mechanical Testing. Based on the basic information of the pipeline in this example, slow strain rate tensile tests and fracture toughness tests were conducted in a hydrogen environment with a total pressure of 4 MPa and 30% hydrogen doping, as well as in an inert environment. The corresponding yield strength, tensile strength, and fracture toughness parameters were obtained.

[0102] σ yH — Yield strength of L245 under a total pressure of 4 MPa and a hydrogen atmosphere with 30% hydrogen doping;

[0103] σ uH —Tensile strength of L245 under a total pressure of 4 MPa and a hydrogen atmosphere with 30% hydrogen content;

[0104] K δH — Fracture toughness of L245 under a total pressure of 4 MPa and a hydrogen atmosphere with 30% hydrogen doping;

[0105] σ y — Yield strength of materials in an inert gas environment;

[0106] σ u — Yield strength of materials in an inert gas environment;

[0107] K δ —Tensile strength of materials in an inert gas environment;

[0108] Step 4: Finite Element Analysis of the Pipeline. A finite element model of the pipeline is established, and the stress distribution of the L245 pipeline in this example is calculated under an internal pressure of 4 MPa. In this example, the internal pressure load is P, and the bending moment load at the defect under this evaluation condition is determined to be M using the finite element method.

[0109] Step 5: Evaluation Criterion Revision. This example illustrates the revision of the safety assessment criteria for volumetric defects:

[0110] Rheological stress of L245 pipeline steel in a total pressure environment of 4 MPa and 30% hydrogen doping The dimensionless plastic limit internal pressure p of a defective hydrogen-doped pipeline under pure internal pressure LSH =p LS ×HE, dimensionless plastic limit bending moment (m) of a defective hydrogen-doped pipeline under pure bending moment. LSH =m LS ×HE, thus the revised safety assessment criterion for volumetric defects is obtained as follows: Where HE represents the hydrogen embrittlement index obtained from mechanical property testing in pure hydrogen / hydrogen-doped environments, p LS and m LS These are the dimensionless plastic limit internal pressure and plastic limit bending moment of a defective pipeline under pure internal pressure and pure bending moment, respectively. They are functions of the defect size and can be calculated with reference to relevant standards.

[0111] Step Six: Integrity Evaluation of Pure Hydrogen / Hydrogen-Blended Gas Pipelines. This example uses defect 1 (volume-type defect) as an illustration:

[0112] Based on the revised safety assessment criteria for volumetric defects, defect 1 in this example is a volumetric defect. According to the data results from the aforementioned stages, in a total pressure environment of 4 MPa and 30% hydrogen doping, this volumetric defect... This defect is acceptable.

[0113] Step 7: Comprehensive evaluation of defective pure hydrogen / hydrogen-blended pipelines. All defects identified in the pipeline section through the aforementioned internal and non-destructive testing are classified and evaluated. If all defects are acceptable, the pipeline section is safe; otherwise, the pipeline section is unsafe and requires further repair or replacement.

[0114] Therefore, the integrity evaluation method for medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines provided by this invention can be used to assess the safety, reliability, and durability of hydrogen transportation pipelines during operation. It combines pure hydrogen / hydrogen-blended gas pipeline integrity evaluation technologies with multiple defect types, involving safety assessment and residual strength evaluation of pipelines with crack-type defects, volumetric defects, and dents. The method includes seven stages: data acquisition, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects, and comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects, to comprehensively and systematically evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines.

[0115] The process includes: data acquisition, which mainly involves collecting basic pipeline information and defect information required for the safety assessment of pipelines with defects, and classifying defects accordingly; macroscopic mechanical performance testing, which is mainly used for the correction of evaluation criteria in the integrity evaluation of pure hydrogen / hydrogen-blended pipelines; finite element calculation, which mainly determines the stress state of the pipeline for the integrity evaluation of pipelines with defects; and evaluation criterion correction, which is based on the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended transportation, to modify the criteria to be applicable to pure hydrogen / hydrogen-blended transportation conditions, and to conduct the integrity evaluation of defective pipelines accordingly, and to provide a comprehensive evaluation result for pipeline integrity management.

[0116] Furthermore, this invention can also achieve real-time monitoring and predictive analysis of pipeline operating status through artificial intelligence and big data analysis technologies, thereby improving pipeline operating efficiency and safety. The process method of this invention has the advantages of being systematic and operable, and can fully consider the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended gas pipeline transportation in medium and low-pressure gas pipelines. This is beneficial to the implementation of the integrity evaluation process for medium and low-pressure pure hydrogen / hydrogen-blended gas pipelines, and is of great significance for the integrity evaluation and safe service of pure hydrogen / hydrogen-blended gas pipeline transportation in medium and low-pressure gas pipelines.

[0117] Figure 3 This diagram illustrates the structure of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided in an embodiment of the present invention. This device applies the aforementioned method. The following is only a brief description of the structure of the device; for other matters not covered herein, please refer to the relevant descriptions in the aforementioned medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation method. Figure 3 The medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided in this embodiment of the invention includes:

[0118] The data acquisition module is used to collect basic pipeline information and pipeline defect information;

[0119] The classification module is used to classify defects based on the pipeline basic information and the pipeline defect information, and to classify defects into volume defects, crack defects and dents;

[0120] The testing module is used to perform macroscopic mechanical tests on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters. The tests include: slow strain rate tensile test and fracture toughness test.

[0121] The calculation module is used to build a finite element model of the pipeline and calculate the stress distribution of the pipeline during actual operation.

[0122] The correction module is used to correct the safety assessment criteria for various defects.

[0123] The first evaluation module is used to evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines based on the safety assessment criteria for the corrected defects.

[0124] The second evaluation module is used to conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects.

[0125] As an optional embodiment of the present invention, the basic pipeline information includes: material, operating pressure, temperature, medium, and hydrogen doping ratio;

[0126] The pipeline defect information includes: shape, location, and size;

[0127] The volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects;

[0128] The crack-type defects include: surface cracks, buried cracks, and penetrating cracks;

[0129] Indentation includes localized elastoplastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface profile.

[0130] As an optional embodiment of the present invention, the testing module performs macroscopic mechanical testing on the pipeline environment in the following manner to obtain yield strength, tensile strength, and fracture toughness parameters:

[0131] Slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments;

[0132] Slow strain rate tensile tests and fracture toughness tests in inert media environments;

[0133] The yield strength, tensile strength, fracture toughness, yield strength, and tensile strength of the material in a pure hydrogen / hydrogen-doped environment, as well as the yield strength and tensile strength of the material in an inert gas environment, were obtained.

[0134] As an optional implementation of this invention, the calculation module establishes a finite element model of the pipeline in the following manner to calculate the stress distribution state of the pipeline during actual operation:

[0135] Based on the operating conditions, pressure, hydrogen doping ratio, temperature, and additional load conditions of pure hydrogen / hydrogen-blended pipelines in actual service, a finite element model is established to calculate the stress distribution of the pipeline during actual operation.

[0136] As an optional implementation of this invention, the correction module corrects the safety assessment criteria for each defect in the following manner:

[0137] Based on the macroscopic mechanical performance test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators for different defect types are corrected for pure hydrogen / hydrogen-doped environment.

[0138] The safety assessment index corrections include: corrections to the safety assessment indexes for volumetric defects, corrections to the safety assessment indexes for crack-type defects, and corrections to the safety assessment indexes for dents.

[0139] in:

[0140] The correction of the volumetric defect safety assessment index includes: pure hydrogen / hydrogen-doped correction of the rheological stress involved in the evaluation process based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; in the process of determining the ultimate load, pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate internal pressure of the defective pipeline under pure internal pressure and pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate bending moment of the defective pipeline under pure bending moment.

[0141] The correction of the safety assessment index for crack-type defects includes: correcting the failure assessment diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments;

[0142] The correction of the indentation safety assessment index includes: correcting the evaluation critical diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment.

[0143] As an optional implementation of this invention, the first evaluation module evaluates the integrity of pure hydrogen / hydrogen-blended gas pipelines based on the safety assessment criteria for the corrected defects in the following manner:

[0144] Based on the defect type, and combining the collected pipeline foundation information, pipeline defect information, and finite element analysis results, the safety of each defect is evaluated according to the revised safety assessment indicators.

[0145] As an optional implementation of this invention, the second evaluation module performs a comprehensive evaluation of the defective pure hydrogen / hydrogen-blended gas pipeline in the following manner:

[0146] Based on the pipeline defect information and the comprehensive safety evaluation results of various defects, a comprehensive evaluation of the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines is made.

[0147] Therefore, the medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided by this invention can be used to assess the safety, reliability, and durability of hydrogen transportation pipelines during operation. It combines pure hydrogen / hydrogen-blended gas pipeline integrity evaluation technologies with multiple defect types, involving safety assessment and residual strength evaluation of pipelines with crack-type defects, volumetric defects, and dents. The process includes seven stages: data acquisition, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects, and comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects, to comprehensively and systematically evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines.

[0148] The process includes: data acquisition, which mainly involves collecting basic pipeline information and defect information required for the safety assessment of pipelines with defects, and classifying defects accordingly; macroscopic mechanical performance testing, which is mainly used for the correction of evaluation criteria in the integrity evaluation of pure hydrogen / hydrogen-blended pipelines; finite element calculation, which mainly determines the stress state of the pipeline for the integrity evaluation of pipelines with defects; and evaluation criterion correction, which is based on the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended transportation, to modify the criteria to be applicable to pure hydrogen / hydrogen-blended transportation conditions, and to conduct the integrity evaluation of defective pipelines accordingly, and to provide a comprehensive evaluation result for pipeline integrity management.

[0149] Furthermore, this invention can also achieve real-time monitoring and predictive analysis of pipeline operating status through artificial intelligence and big data analysis technologies, thereby improving pipeline operating efficiency and safety. The process method of this invention has the advantages of being systematic and operable, and can fully consider the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended gas pipeline transportation in medium and low-pressure gas pipelines. This is beneficial to the implementation of the integrity evaluation process for medium and low-pressure pure hydrogen / hydrogen-blended gas pipelines, and is of great significance for the integrity evaluation and safe service of pure hydrogen / hydrogen-blended gas pipeline transportation in medium and low-pressure gas pipelines.

[0150] The above are merely embodiments of this application and are 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 evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines, characterized in that, include: Collect basic pipeline information and pipeline defect information; Based on the pipeline basic information and the pipeline defect information, defects are classified into volumetric defects, crack defects, and dents. Macroscopic mechanical tests are performed on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters, wherein the tests include: slow strain rate tensile test and fracture toughness test; Establish a finite element model of the pipeline and calculate the stress distribution state of the pipeline during actual operation; Revise the safety assessment criteria for each defect; Integrity assessment of pure hydrogen / hydrogen-blended gas pipelines is conducted based on the revised defect safety assessment criteria. A comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines; in: The macroscopic mechanical tests performed on the pipeline environment to obtain yield strength, tensile strength, and fracture toughness parameters include: Slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments; Slow strain rate tensile tests and fracture toughness tests in inert media environments; The yield strength, tensile strength, fracture toughness, yield strength, and tensile strength of the material in a pure hydrogen / hydrogen-doped environment were obtained; The safety assessment criteria for correcting each defect include: Based on the macroscopic mechanical performance test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators for different defect types are corrected for pure hydrogen / hydrogen-doped environment. The safety assessment index revisions include: revisions to the safety assessment indexes for volumetric defects, revisions to the safety assessment indexes for crack-type defects, and revisions to the safety assessment indexes for dents. in: The correction of the volumetric defect safety assessment index includes: pure hydrogen / hydrogen-doped correction of the rheological stress involved in the evaluation process based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; in the process of determining the ultimate load, pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate internal pressure of the defective pipeline under pure internal pressure and pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate bending moment of the defective pipeline under pure bending moment. The correction of the safety assessment index for crack-type defects includes: correcting the failure assessment diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments; The correction of the indentation safety assessment index includes: correcting the evaluation critical diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment.

2. The method according to claim 1, characterized in that, The basic information of the pipeline includes: material, operating pressure, temperature, medium, and hydrogen doping ratio; The pipeline defect information includes: shape, location, and size.

3. The method according to claim 2, characterized in that, The volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects; The crack-type defects include: surface cracks, buried cracks, and penetrating cracks; Indentation includes localized elastoplastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface profile.

4. The method according to claim 3, characterized in that, The establishment of the finite element model of the pipeline and the calculation of the stress distribution state of the pipeline during actual operation include: Based on the operating conditions, pressure, hydrogen doping ratio, temperature, and additional load conditions of pure hydrogen / hydrogen-blended pipelines in actual service, a finite element model is established to calculate the stress distribution of the pipeline during actual operation.

5. The method according to claim 4, characterized in that, The integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines based on the corrected defect safety assessment criteria includes: Based on the defect type, and combining the collected pipeline foundation information, pipeline defect information, and finite element analysis results, the safety of each defect is evaluated according to the revised safety assessment indicators.

6. The method according to claim 5, characterized in that, The comprehensive evaluation of defective pure hydrogen / hydrogen-blended gas pipelines includes: Based on the pipeline defect information and the comprehensive safety evaluation results of various defects, a comprehensive evaluation of the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines is made.

7. A device for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended gas pipelines, characterized in that, include: The data acquisition module is used to collect basic pipeline information and pipeline defect information; The classification module is used to classify defects based on the pipeline basic information and the pipeline defect information, and to classify defects into volume defects, crack defects and dents; The testing module is used to perform macroscopic mechanical tests on the pipeline environment to obtain yield strength, tensile strength and fracture toughness parameters. The tests include: slow strain rate tensile test and fracture toughness test. The calculation module is used to build a finite element model of the pipeline and calculate the stress distribution of the pipeline during actual operation. The correction module is used to correct the safety assessment criteria for various defects. The first evaluation module is used to evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines based on the safety assessment criteria for the corrected defects. The second evaluation module is used to conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines with defects; in: The testing module performs macroscopic mechanical tests on the pipeline environment in the following manner to obtain yield strength, tensile strength, and fracture toughness parameters: Slow strain rate tensile tests and fracture toughness tests in pure hydrogen / hydrogen-doped environments; Slow strain rate tensile tests and fracture toughness tests in inert media environments; The yield strength, tensile strength, fracture toughness, yield strength, and tensile strength of the material in a pure hydrogen / hydrogen-doped environment were obtained; The correction module corrects the safety assessment criteria for each defect in the following manner: Based on the macroscopic mechanical performance test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators for different defect types are corrected for pure hydrogen / hydrogen-doped environment. The safety assessment index revisions include: revisions to the safety assessment indexes for volumetric defects, revisions to the safety assessment indexes for crack-type defects, and revisions to the safety assessment indexes for dents. in: The correction of the volumetric defect safety assessment index includes: pure hydrogen / hydrogen-doped correction of the rheological stress involved in the evaluation process based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; in the process of determining the ultimate load, pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate internal pressure of the defective pipeline under pure internal pressure and pure hydrogen / hydrogen-doped correction of the dimensionless plastic ultimate bending moment of the defective pipeline under pure bending moment. The correction of the safety assessment index for crack-type defects includes: correcting the failure assessment diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environments and inert environments; The correction of the indentation safety assessment index includes: correcting the evaluation critical diagram based on the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment.

8. The apparatus according to claim 7, characterized in that, The basic information of the pipeline includes: material, operating pressure, temperature, medium, and hydrogen doping ratio; The pipeline defect information includes: shape, location, and size; The volumetric defects include: pipe corrosion, surface metal loss, and manufacturing defects; The crack-type defects include: surface cracks, buried cracks, and penetrating cracks; Indentation includes localized elastoplastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface profile.

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