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

Abstract

The invention provides a method and device for evaluating the integrity of a medium-low pressure pure hydrogen / hydrogen-doped gas pipeline, and the method comprises seven links: data collection, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of a defect-containing pure hydrogen / hydrogen-doped gas pipeline, and comprehensive evaluation of the defect-containing pure hydrogen / hydrogen-doped gas pipeline. The method has the advantages of systematization and operability, can fully consider the influence of pure hydrogen / hydrogen-doped conveying of the medium and low pressure gas pipeline on the pipeline defect evaluation and the change of the residual strength of the pipeline, and is beneficial to the implementation of the integrity evaluation process of the medium and low pressure pure hydrogen / hydrogen-doped gas pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline management, and in particular to a method and device for evaluating the integrity of medium- and low-pressure pure hydrogen / hydrogen-blended fuel gas pipelines. Background Art

[0002] At present, my country's hydrogen energy industry is entering a fast lane of development. The demand for hydrogen in urban areas will continue to increase. It is urgent to accelerate the green transformation of energy, promote the development of the hydrogen energy industry, and use medium and low pressure pure hydrogen or hydrogen-blended gas to transport to households and achieve large-scale application. The safety issues of pure hydrogen / hydrogen-blended transmission pipelines run through the entire life cycle of gas pipeline design, construction, operation, and maintenance.

[0003] However, due to the low density and high flammability and explosiveness of hydrogen, the safety of hydrogen pipeline transportation has become an internationally recognized technical difficulty; at the same time, due to the high and non-emission characteristics of hydrogen, the use of medium and low pressure pure hydrogen or hydrogen-blended gas to transport to households and realize large-scale application also urgently needs to overcome the technical difficulties in intrinsic safety, transportation process, key equipment, etc. At present, the integrity evaluation method of gas pipelines is relatively systematic, but the impact of hydrogen-blended or pure hydrogen transportation on pipeline defect assessment and the change of pipeline residual strength are not taken into consideration. There are certain limitations, and it is impossible to comprehensively and systematically evaluate the integrity of pure hydrogen / hydrogen-blended pipelines during operation. On the one hand, the existing research mainly focuses on the stress-strain curve of materials obtained by hydrogen-blended small-size specimen tests under the conditions of hydrogen-blended transportation of gas pipelines, as well as the fracture toughness of materials under different hydrogen-blending ratios, etc., to study the influence of hydrogen-blending on the hydrogen embrittlement behavior of materials. Only the influence of hydrogen-blending on material properties is considered, and there is a lack of exploration of the influence of defective pipelines on defect assessment after hydrogen-blended transportation and the influence of pipeline residual strength. On the other hand, the existing integrity evaluation methods are for conventional oil pipelines or gas pipelines. The existing integrity evaluation methods do not consider the impact of hydrogen on the safety assessment of defective pipelines. The applicability of its safety assessment criteria in pure hydrogen / hydrogen-blended gas pipelines is unclear, and its corresponding evaluation criteria need to be adjusted according to the hydrogen blending conditions. Therefore, on the basis of traditional pipeline integrity evaluation, considering the impact of pipeline defect assessment and the change of residual strength caused by hydrogen transportation, the establishment of a pure hydrogen / hydrogen-blended gas pipeline integrity evaluation method and system is of great significance to the safety of pure hydrogen / hydrogen-blended gas transportation. Summary of the invention

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

[0005] To achieve the above object, 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 a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline, comprising:

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

[0008] Classifying defects according to the pipeline basic information and the pipeline defect information, and classifying the defects into volume defects, crack defects and depressions;

[0009] Performing macroscopic mechanical tests 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 pipeline finite element model and calculate the stress distribution state of the pipeline during actual operation;

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

[0012] Conduct integrity assessment of pure hydrogen / hydrogen-blended gas pipelines based on the revised safety assessment criteria for defects;

[0013] Conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects.

[0014] Optionally, the basic information of the pipeline includes: material, operating pressure, temperature, medium and hydrogen blending 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 through cracks;

[0018] Concavity includes: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

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

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

[0021] Slow strain rate tensile test and fracture toughness test in inert medium environment;

[0022] The yield strength of materials in pure hydrogen / hydrogen-doped environments, the tensile strength of materials in pure hydrogen / hydrogen-doped environments, the fracture toughness of materials in pure hydrogen / hydrogen-doped environments, the yield strength of materials in inert gas environments, the yield strength of materials in inert gas environments and the tensile strength of materials in inert gas environments are obtained.

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

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

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

[0026] According to the macroscopic mechanical property test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators of different defect types are corrected for pure hydrogen / hydrogen-doped respectively;

[0027] The safety assessment index correction includes: volume defect safety assessment index correction, crack defect safety assessment index correction and dent safety assessment index correction;

[0028] in:

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

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

[0031] The correction of the dent safety assessment index includes: correcting the evaluation critical diagram according to the macroscopic mechanical properties in a pure hydrogen / hydrogen-doped environment and an inert environment.

[0032] Optionally, the pure hydrogen / hydrogen-blended gas pipeline integrity assessment based on the corrected defect safety assessment criteria includes:

[0033] According to the defect type, combined with the collected pipeline basic 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 the pure hydrogen / hydrogen-blended gas pipeline containing defects includes:

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

[0036] Another aspect of the present invention provides a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity assessment device, comprising:

[0037] Collection module, used to collect basic information and pipeline defect information of pipelines;

[0038] A classification module, used to classify defects according to the pipeline basic information and the pipeline defect information, and classify the defects into volume defects, crack defects and depressions;

[0039] A test module is used to perform macroscopic mechanical tests 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;

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

[0041] Correction module, used to correct the safety assessment criteria of each defect;

[0042] The first evaluation module is used to evaluate the integrity of the pure hydrogen / hydrogen-blended gas pipeline according to the corrected safety assessment criteria of the defects;

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

[0044] Optionally, the basic information of the pipeline includes: material, operating pressure, temperature, medium and hydrogen blending 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 through cracks;

[0048] Concavity includes: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

[0049] It can be seen that the medium and low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation method and device provided by the present invention include seven links: data acquisition, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, defective pure hydrogen / hydrogen-blended gas pipeline integrity evaluation, and defective pure hydrogen / hydrogen-blended gas pipeline comprehensive evaluation. The present invention has the advantages of systematization and operability, and can fully consider the impact of pure hydrogen / hydrogen-blended transportation of medium and low pressure gas pipelines on pipeline defect assessment and changes in pipeline residual strength, which is beneficial to the implementation of the medium and low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0051] Figure 1 A flow chart of a method for evaluating the integrity of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline provided in an embodiment of the present invention;

[0052] Figure 2 A schematic flow chart of a method for evaluating the integrity of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline provided in an embodiment of the present invention;

[0053] Figure 3 A schematic diagram of the structure of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline integrity assessment device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

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

[0056] In order to solve the above problems, the present invention provides a method and device for evaluating the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines, including data collection, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects, and comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects. The present invention has the advantages of systematization and operability, and can fully consider the impact of pure hydrogen / hydrogen-blended transportation of medium and low pressure gas pipelines on pipeline defect assessment and changes in pipeline residual strength, which is beneficial to the implementation of the integrity evaluation process of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines.

[0057] Figure 1 The flowchart of the method for evaluating the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines provided by an embodiment of the present invention is shown. Figure 2 A schematic diagram of the process of evaluating the integrity of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline provided by an embodiment of the present invention is shown. Figure 1 and Figure 2 The embodiment of the present invention provides a method for evaluating the integrity of a medium- and low-pressure pure hydrogen / hydrogen-blended gas pipeline, comprising:

[0058] S1, collect pipeline basic information and pipeline defect information.

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

[0060] Specifically, the data collection link refers to the collection of relevant data supporting the integrity evaluation of pure hydrogen / hydrogen-blended gas pipelines, including basic pipeline information such as material, operating pressure, temperature, medium, hydrogen blending ratio, and pipeline defect information obtained through internal inspection, non-destructive inspection, etc. The data collection part can be combined with other pipeline monitoring and detection systems to read the corresponding pipeline monitoring and detection data in real time, and identify and classify the data according to the data content and form required by this system, so as to serve as the basic data for subsequent integrity evaluation.

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

[0062] The volume defects include: pipe corrosion, surface metal loss and manufacturing defects; the crack defects include: surface cracks, buried cracks and through cracks; depressions include: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

[0063] Specifically, the defect classification link refers to the classification of defects detected in pure hydrogen / hydrogen-blended gas pipelines into three categories: volume defects, crack defects and depressions based on parameters such as shape, position and size, based on pipeline defect information obtained through internal inspection, non-destructive testing and other methods. Volume defects include pipe body corrosion, surface metal loss, manufacturing defects, etc. Crack defects include surface cracks, buried cracks and penetrating cracks, etc. Depressions include local elastic-plastic deformation in which the curvature of the pipeline surface is significantly lower than the pipeline surface contour due to external force impact or extrusion during construction or operation.

[0064] S3, performing macroscopic mechanical tests 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.

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

[0066] Specifically, the macroscopic mechanical testing includes slow strain rate tensile testing and fracture toughness testing in pure hydrogen / hydrogen-doped environments, as well as corresponding tests in inert medium environments as controls. The corresponding yield strength, tensile strength and fracture toughness parameters need to be obtained through macroscopic mechanical testing:

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

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

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

[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 pipeline finite element model and calculate the stress distribution state of the pipeline during actual operation.

[0074] The establishing of the pipeline finite element model and calculating the stress distribution state of the pipeline during actual operation includes: calculating the stress distribution state of the pipeline during actual operation by establishing a finite element model according to the operating conditions, pressure, hydrogen blending ratio, temperature and additional load conditions of the pure hydrogen / hydrogen blended pipeline in actual service conditions.

[0075] Specifically, the pipeline finite element analysis link refers to the calculation of the stress distribution state of the pipeline during actual operation through 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 in actual service conditions.

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

[0077] The safety assessment criteria for correcting each defect include: performing pure hydrogen / hydrogen-doped correction on the safety assessment indicators of different defect types according to the macroscopic mechanical properties test results in pure hydrogen / hydrogen-doped environment and inert environment; the safety assessment indicator correction includes: safety assessment indicator correction for volume defect, safety assessment indicator correction for crack defect and safety assessment indicator correction for dent; wherein: the safety assessment indicator correction for volume defect includes: performing rheological stress correction on the rheological stress involved in the evaluation process according to the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; Pure hydrogen / hydrogen-doped correction; in the process of determining the limit load, the plastic limit internal pressure of the dimensionless defective pipeline under pure internal pressure is corrected by pure hydrogen / hydrogen-doped correction, and the plastic limit bending moment of the dimensionless defective pipeline under pure bending moment is corrected by pure hydrogen / hydrogen-doped correction; the correction of the safety assessment index of the crack type defect includes: correcting the failure assessment diagram according to the macroscopic mechanical properties in the pure hydrogen / hydrogen-doped environment and the inert environment; the correction of the safety assessment index of the dent includes: correcting the evaluation critical diagram according to the macroscopic mechanical properties in the pure hydrogen / hydrogen-doped environment and the inert environment.

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

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

[0080] The correction of the safety assessment index of volumetric defects refers to the correction of the rheological stress involved in the evaluation process according to the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment. Perform pure hydrogen / hydrogen blending correction In the process of determining the limit load, the dimensionless plastic limit internal pressure p of the defective pipe under pure internal pressure is LS Perform pure hydrogen / hydrogen blending correction LSH , the plastic limit bending moment m of the dimensionless defective pipe under pure bending moment LS Perform pure hydrogen / hydrogen blending correction m LSH .

[0081] The correction of crack-type defect safety assessment index refers to the correction of failure assessment diagram according to the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment.

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

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

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

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

[0086] S7, conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects.

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

[0088] Specifically, the comprehensive evaluation link of defective pure hydrogen / hydrogen-blended pipelines refers to the defect information of pure hydrogen / hydrogen-blended gas pipelines obtained through in-pipeline inspection and non-destructive testing, and the safety evaluation results of various defects are integrated to make a comprehensive evaluation of the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines.

[0089] The following is a demonstration using a medium-pressure pure hydrogen gas pipeline as an example. The maximum operating pressure of the pipeline is 4MPa, the hydrogen blending ratio is 30%, and the pipeline material is L245 pipeline steel.

[0090] Step 1: Data collection, including basic pipeline information and pipeline defect information. In this embodiment:

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

[0092] The pipe section defect information obtained through internal testing, non-destructive testing and other means includes:

[0093] Defect 1 - The tube body is manufactured abnormally, with a depth of 23%, a length of 11mm and a width of 32mm.

[0094] Defect 2 - Depression: The maximum depth of the depression is ddp = 15mm, the radius of the depression is rd = 26mm, the length is 25mm, the width is 48mm, the distance between the defect and the weld is Lw = 1524mm, and the distance between the defect and the discontinuity of the main pipeline is Lmsd = 2.2m.

[0095] Defect 3——

[0096] Step 2: Defect classification. According to the data collection results in step 1, the defects are classified, where defect 1 is a volume defect, defect 2 is a dent, and defect 3 is... Take defect 1 as an example to illustrate:

[0097] Defect 1, volume defect, the defect is dimensionally processed as follows:

[0098] Relative axial length:

[0099] Relative circumferential length:

[0100] Relative depth: c = 0.23

[0101] Step 3: Macro-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 4MPa and 30% hydrogen doping and an inert environment, respectively, to obtain the corresponding yield strength, tensile strength and fracture toughness parameters:

[0102] σ yH ——Yield strength of L245 in a total pressure of 4MPa-30% hydrogen environment;

[0103] σ uH ——Tensile strength of L245 in a total pressure of 4MPa-30% hydrogen environment;

[0104] K δH ——Fracture toughness of L245 in a total pressure of 4MPa-30% hydrogen environment;

[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 pipelines. Establish a pipeline finite element model and calculate the stress distribution state of the L245 pipeline in this example under the condition of 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 by the finite element method.

[0109] Step 5: Modification of evaluation criteria. This example takes the modification of safety assessment criteria for volumetric defects as an example:

[0110] Flow stress of L245 pipeline steel in a total pressure of 4MPa-30% hydrogen-doped environment Dimensionless plastic limit internal pressure p of defective hydrogen-blended pipeline under pure internal pressure LSH =p LS ×HE, dimensionless plastic limit bending moment of defective hydrogen-doped pipeline under pure bending moment m LSH =m LS ×HE, the modified safety assessment criterion for volumetric defects is: HE is the hydrogen embrittlement index obtained from the mechanical properties test in pure hydrogen / hydrogen-doped environments, and p LS and m LS They are the dimensionless plastic limit internal pressure of the defective pipe under pure internal pressure and the plastic limit bending moment under pure bending moment, which are functions of the defect size and can be calculated with reference to relevant standards.

[0111] Step 6: Integrity assessment of pure hydrogen / hydrogen-blended gas pipelines. This example uses defect 1, volumetric defect, as an example:

[0112] According to the revised safety assessment criteria for volumetric defects, defect 1 in this example is a volumetric defect. Based on the data results of the above links, it is obtained that in a total pressure 4MPa-30% hydrogen-doped environment, this volumetric defect This defect is acceptable.

[0113] Step 7: Comprehensive evaluation of pure hydrogen / hydrogen-blended pipelines with defects. Classify and evaluate the various defects found in the pipe section through the aforementioned internal inspection and non-destructive testing. If all defects are acceptable, the pipe section is safe. Otherwise, the pipe section is unsafe and requires further repair or replacement.

[0114] It can be seen that the medium and low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation method provided by the embodiment of the present invention can be used to evaluate the safety, reliability and durability of the hydrogen pipeline during operation. It combines the pure hydrogen / hydrogen-blended pipeline integrity evaluation technology containing multiple defect types, involving the safety assessment and residual strength evaluation of pipelines containing crack-type defects, volume defects and depressions, including data collection, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, defect pure hydrogen / hydrogen-blended gas pipeline integrity evaluation, and defect pure hydrogen / hydrogen-blended gas pipeline comprehensive evaluation. Seven links are used to comprehensively and systematically evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines.

[0115] Among them: data collection is mainly to collect the basic information and defect information of the pipeline required for the safety assessment of defective pipelines, and to classify the defects based on this; the macro-mechanical properties test is mainly used to correct the evaluation criteria in the integrity evaluation of pure hydrogen / hydrogen-blended pipelines; the finite element calculation link is mainly to determine the stress state of the pipeline in order to evaluate the integrity of defective pipelines; the evaluation criterion correction is mainly based on the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended transportation, and the criteria are corrected to be suitable for pure hydrogen / hydrogen-blended transportation conditions, and the defective pipeline integrity evaluation is carried out accordingly, and the evaluation results are comprehensively given for pipeline integrity management.

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

[0117] Figure 3 The structure diagram of the medium-low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided by an embodiment of the present invention is shown. The medium-low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device applies the above method. The following is only a brief description of the structure of the medium-low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device. For other matters not covered, please refer to the relevant description in the above medium-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 assessment device provided by the embodiment of the present invention comprises:

[0118] Collection module, used to collect basic information and pipeline defect information of pipelines;

[0119] A classification module, used to classify defects according to the pipeline basic information and the pipeline defect information, and classify the defects into volume defects, crack defects and depressions;

[0120] A test module is used to perform macroscopic mechanical tests 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;

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

[0122] Correction module, used to correct the safety assessment criteria of each defect;

[0123] The first evaluation module is used to evaluate the integrity of the pure hydrogen / hydrogen-blended gas pipeline according to the corrected safety assessment criteria of the defects;

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

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

[0129] Concavity includes: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

[0130] As an optional implementation of the embodiment of the present invention, the test 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 test and fracture toughness test in pure hydrogen / hydrogen-doped environment;

[0132] Slow strain rate tensile test and fracture toughness test in inert medium environment;

[0133] The yield strength of materials in pure hydrogen / hydrogen-doped environments, the tensile strength of materials in pure hydrogen / hydrogen-doped environments, the fracture toughness of materials in pure hydrogen / hydrogen-doped environments, the yield strength of materials in inert gas environments, the yield strength of materials in inert gas environments and the tensile strength of materials in inert gas environments are obtained.

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

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

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

[0137] According to the macroscopic mechanical property test results in pure hydrogen / hydrogen-doped environment and inert environment, the safety assessment indicators of different defect types are corrected for pure hydrogen / hydrogen-doped respectively;

[0138] The safety assessment index correction includes: volume defect safety assessment index correction, crack defect safety assessment index correction and dent safety assessment index correction;

[0139] in:

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

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

[0142] The correction of the dent safety assessment index includes: correcting the evaluation critical diagram according to the macroscopic mechanical properties in a pure hydrogen / hydrogen-doped environment and an inert environment.

[0143] As an optional implementation of the embodiment of the present invention, the first evaluation module performs the integrity evaluation of the pure hydrogen / hydrogen-blended gas pipeline according to the safety assessment criteria of the modified defects in the following manner:

[0144] According to the defect type, combined with the collected pipeline basic 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 the embodiment of the present invention, the second evaluation module comprehensively evaluates the pure hydrogen / hydrogen-blended gas pipeline containing defects in the following manner:

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

[0147] It can be seen that the medium and low pressure pure hydrogen / hydrogen-blended gas pipeline integrity evaluation device provided by the embodiment of the present invention can be used to evaluate the safety, reliability and durability of the hydrogen pipeline during operation. It combines the pure hydrogen / hydrogen-blended pipeline integrity evaluation technology containing multiple defect types, involving the safety assessment and residual strength evaluation of pipelines containing crack-type defects, volume defects and depressions, including data collection, defect classification, macroscopic mechanical testing, finite element calculation, evaluation criterion correction, defect pure hydrogen / hydrogen-blended gas pipeline integrity evaluation, and defect pure hydrogen / hydrogen-blended gas pipeline comprehensive evaluation. Seven links are used to comprehensively and systematically evaluate the integrity of pure hydrogen / hydrogen-blended gas pipelines.

[0148] Among them: data collection is mainly to collect the basic information and defect information of the pipeline required for the safety assessment of defective pipelines, and to classify the defects based on this; the macro-mechanical properties test is mainly used to correct the evaluation criteria in the integrity evaluation of pure hydrogen / hydrogen-blended pipelines; the finite element calculation link is mainly to determine the stress state of the pipeline in order to evaluate the integrity of defective pipelines; the evaluation criterion correction is mainly based on the changes in pipeline integrity caused by pure hydrogen / hydrogen-blended transportation, and the criteria are corrected to be suitable for pure hydrogen / hydrogen-blended transportation conditions, and the defective pipeline integrity evaluation is carried out accordingly, and the evaluation results are comprehensively given for pipeline integrity management.

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

[0150] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present 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 information and pipeline defect information of pipelines; Classifying defects according to the pipeline basic information and the pipeline defect information, and classifying the defects into volume defects, crack defects and depressions; Performing macroscopic mechanical tests 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 pipeline finite element model and calculate the stress distribution state of the pipeline during actual operation; Correct the safety assessment criteria for each defect; Conduct integrity assessment of pure hydrogen / hydrogen-blended gas pipelines based on the revised safety assessment criteria for defects; Conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects.

2. The method according to claim 1, characterized in that The basic information of the pipeline includes: material, operating pressure, temperature, medium and hydrogen blending 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 through cracks; Concavity includes: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

4. The method according to claim 3, characterized in that The macroscopic mechanical test of the pipeline environment is performed to obtain the yield strength, tensile strength and fracture toughness parameters including: Slow strain rate tensile test and fracture toughness test in pure hydrogen / hydrogen-doped environment; Slow strain rate tensile test and fracture toughness test in inert medium environment; The yield strength of materials in pure hydrogen / hydrogen-doped environments, the tensile strength of materials in pure hydrogen / hydrogen-doped environments, the fracture toughness of materials in pure hydrogen / hydrogen-doped environments, the yield strength of materials in inert gas environments, the yield strength of materials in inert gas environments and the tensile strength of materials in inert gas environments are obtained.

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

6. The method according to claim 5, characterized in that The safety assessment criteria for correcting each defect include: According to the macroscopic mechanical property test results in pure hydrogen / hydrogen-doped environment and inert environment, pure hydrogen / hydrogen-doped corrections are made to the safety assessment indicators of different defect types respectively; The safety assessment index correction includes: volume defect safety assessment index correction, crack defect safety assessment index correction and dent safety assessment index correction; in: The correction of the volume defect safety assessment index includes: performing pure hydrogen / hydrogen-doped correction on the rheological stress involved in the evaluation process according to the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; performing pure hydrogen / hydrogen-doped correction on the plastic limit internal pressure of the dimensionless defective pipeline under pure internal pressure, and performing pure hydrogen / hydrogen-doped correction on the plastic limit bending moment of the dimensionless defective pipeline under pure bending moment in the process of determining the limit load; The correction of the safety assessment index of crack type defects includes: correcting the failure assessment diagram according to the macroscopic mechanical properties in pure hydrogen / hydrogen-doped environment and inert environment; The correction of the dent safety assessment index includes: correcting the evaluation critical diagram according to the macroscopic mechanical properties in a pure hydrogen / hydrogen-doped environment and an inert environment.

7. The method according to claim 6, characterized in that The integrity assessment of pure hydrogen / hydrogen-blended gas pipeline based on the modified defect safety assessment criteria includes: According to the defect type, combined with the collected pipeline basic information, pipeline defect information, and finite element analysis results, the safety of each defect is evaluated according to the revised safety assessment indicators.

8. The method according to claim 7, characterized in that The comprehensive evaluation of the pure hydrogen / hydrogen-blended gas pipeline containing defects includes: Based on the pipeline defect information and comprehensive safety evaluation results of various defects, a comprehensive evaluation is made on the integrity of medium and low pressure pure hydrogen / hydrogen-blended gas pipelines.

9. A medium and low pressure pure hydrogen / hydrogen-blended gas pipeline integrity assessment device, characterized in that: include: Collection module, used to collect basic information and pipeline defect information of pipelines; A classification module, used to classify defects according to the pipeline basic information and the pipeline defect information, and classify the defects into volume defects, crack defects and depressions; A test module is used to perform macroscopic mechanical tests 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; The calculation module is used to establish a pipeline finite element model and calculate the stress distribution state of the pipeline during actual operation; Correction module, used to correct the safety assessment criteria of each defect; The first evaluation module is used to evaluate the integrity of the pure hydrogen / hydrogen-blended gas pipeline according to the corrected safety assessment criteria of the defects; The second evaluation module is used to conduct a comprehensive evaluation of pure hydrogen / hydrogen-blended gas pipelines containing defects.

10. The device according to claim 9, characterized in that The basic information of the pipeline includes: material, operating pressure, temperature, medium and hydrogen blending 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 through cracks; Concavity includes: local elastic-plastic deformation where the curvature of the pipe surface is significantly lower than the pipe surface contour.

Images