Lifetime Evaluation System and Lifetime Evaluation Method

Abstract

To provide a lifespan evaluation system capable of relatively accurately evaluating lifespan evaluation of a nozzle in a short time.SOLUTION: A lifespan evaluation system in at least an embodiment of the disclosure includes: a first stress calculation unit that handles at least one of a nozzle welded portion of a header or piping or a base material around the nozzle hole of the header or the piping in a thermal power plant as a first evaluation portion, which is the object of life evaluation, calculates the stress-lifespan evaluation used in lifespan evaluation for the first evaluation portion based on nozzle type, header size, nozzle size, rated pressure, rated temperature, and steel type relevant to the first evaluation portion; and a first lifespan evaluation unit that evaluates the lifespan of the first evaluation portion based on the stress-lifespan evaluation.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a life evaluation system and a life evaluation method.

Background Art

[0002] In boiler equipment and piping equipment provided in thermal power plants, as the operating temperature rises, high-chromium steel classified as high-strength heat-resistant steel is used. However, in the vicinity of the joints between the main pipes such as pipe supports and pipes and the pipes that are connected to them and constitute the pipe stand, due to the severe stress environment where thermal stress, internal pressure, bending stress due to self-weight, etc. are applied, it is essential to evaluate creep damage. Conventionally, creep analysis of pipe stands has been performed by creep damage evaluation using non-destructive inspection and creep damage evaluation using the finite element method (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, pipe stands have various shapes and dimensions, and the tendency of the generated stress differs for each shape and dimension. Therefore, in order to appropriately evaluate the life, evaluation by FEM elastic creep analysis is necessary. However, since the shapes of pipe stands used in thermal power plants are diverse, a great deal of time and labor are required for evaluation by FEM elastic creep analysis.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to evaluate the life of a pipe stand in a relatively short time with relatively high accuracy.

Means for Solving the Problems

[0006] (1) The life evaluation system according to at least one embodiment of the present disclosure includes using at least one of the pipe support or the pipe base weld of the pipe in the thermal power plant, or the base metal part around the pipe base hole of the pipe support or the pipe as a first evaluation part to be the object of life evaluation, and calculating a life evaluation stress for evaluating the life of the first evaluation part based on the pipe base type, the main pipe dimension, the pipe base dimension, the evaluation pressure, the evaluation temperature, and the steel material type related to the first evaluation part; a first stress calculation part a first life evaluation part for evaluating the life of the first evaluation part based on the life evaluation stress and comprising.

[0007] (2) The life evaluation method according to at least one embodiment of the present disclosure includes using at least one of the pipe support or the pipe base weld of the pipe in the thermal power plant, or the base metal part around the pipe base hole of the pipe support or the pipe as a first evaluation part to be the object of life evaluation, and calculating a life evaluation stress for evaluating the life of the first evaluation part based on the pipe base type, the main pipe dimension, the pipe base dimension, the evaluation pressure, the evaluation temperature, and the steel material type related to the first evaluation part; a step a step of evaluating the life of the first evaluation part based on the life evaluation stress and comprising.

Advantages of the Invention

[0008] According to at least one embodiment of the present disclosure, the life of the pipe base can be evaluated relatively accurately in a short time.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 4A

Figure 4B

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Figure 4D

Figure 4E

Figure 4F

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Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure thereto, but are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states in which there are tolerances or relative displacements with angles or distances that can obtain the same function. For example, expressions representing that things such as "identical", "equal", and "homogeneous" are in an equal state not only strictly represent an equal state, but also represent states in which there are tolerances or differences that can obtain the same function. For example, expressions representing shapes such as a rectangular shape or a cylindrical shape shall represent not only the geometrically exact shapes such as a rectangular shape or a cylindrical shape, but also shapes including concavo-convex portions, chamfered portions, etc. within the range where the same effects can be obtained. On the other hand, expressions such as "comprising", "having", "including", or "possessing" one component are not exclusive expressions that exclude the existence of other components.

[0011] (Overall Configuration of Life Evaluation System 100) FIG. 1 is a block diagram showing the configuration of the life evaluation system according to the present embodiment. The life evaluation system according to the present embodiment is a system for evaluating the life of piping in a thermal power plant. The life evaluation system 100 according to the present embodiment includes a processing unit 101, an input unit 103, a storage unit 105, and an output unit 107. The processing unit 101 is a computer system provided together with the input unit 103, the storage unit 105, and the output unit 107. Note that the life evaluation system 100 may be a server provided on a network and having the functions of the processing unit 101. If the processing unit 101 is a server provided on the network, the storage unit 105 may be a database provided on the network, and the input unit 103 and the output unit 107 may be parts of terminals connected via the network.

[0012] The input unit 103 is an input device such as a so-called keyboard or mouse, and is used for input operations of various data necessary for life evaluation related to the piping of a thermal power plant.

[0013] The processing unit 101 is composed of a CPU or the like, and by executing various programs stored in the storage unit 105, various processes necessary for the life evaluation system 100 are executed. In the present embodiment, the processing unit 101 has, as functional blocks, a first stress calculation unit 111, a first life evaluation unit 113, a second stress calculation unit 121, a time history calculation unit 122, and a second life evaluation unit 123. Details of the first stress calculation unit 111, the first life evaluation unit 113, the second stress calculation unit 121, the time history calculation unit 122, and the second life evaluation unit 123 will be described in detail later.

[0014] The storage unit 105 stores various programs used in the processing by the processing unit 101 and various types of data necessary for the implementation of the programs.

[0015] The output unit 107 is a notification device such as a so-called monitor, and outputs, as output data, the evaluation result of the life of the piping of the thermal power generation plant calculated by the processing unit 101.

[0016] (Regarding the life evaluation of the piping of a thermal power generation plant) In the boiler equipment and piping equipment provided in a thermal power generation plant, as the operating temperature rises, high-chromium steel classified as high-strength heat-resistant steel is used. However, in the vicinity of the joint between the main pipe such as pipe alignment and piping and the pipes that are connected to them and form a pipe support, due to the severe stress environment where thermal stress, internal pressure, bending stress due to its own weight, etc. are applied, the evaluation of creep damage is essential. Pipe supports have various shapes and dimensions, and the tendency of the generated stress differs for each shape and dimension. Therefore, in order to appropriately evaluate the life, evaluation by FEM elastic creep analysis is necessary. However, since the shapes of pipe supports used in thermal power generation plants are diverse, a great deal of time and effort are required for evaluation by FEM elastic creep analysis.

[0017] As a result of the inventors' intensive studies, FEM elastic creep analysis was performed in advance for a plurality of patterns with different header types and dimensions of each part of the header. Based on the analysis results, by parameterizing the life evaluation stress, it was found that the life evaluation stress can be easily calculated from the header type, main pipe dimensions, header dimensions, evaluation pressure, evaluation temperature, and steel type. Thereby, when evaluating the life of the first evaluation site, the life of the header can be evaluated with relatively high accuracy without newly performing FEM elastic creep analysis.

[0018] (Regarding the life evaluation of the first evaluation site in the life evaluation system 100) Hereinafter, the life evaluation in the life evaluation system 100 according to the present embodiment will be described. FIG. 2 is a flowchart schematically showing the life evaluation procedure for the first evaluation site of the life evaluation system 100 according to the present embodiment. The life evaluation method using the life evaluation system 100 according to the present embodiment includes a step S1 of inputting data related to the first evaluation site, a step S3 of calculating the life evaluation stress, a step S5 of evaluating the life, and a step S7 of outputting the result of the life evaluation.

[0019] (Step S1 of inputting data related to the first evaluation site) Step S1 of inputting data related to the first evaluation site according to the present embodiment is a step of inputting various data related to the first evaluation site into the processing unit 101. Here, the first evaluation site according to the present embodiment is the pipe alignment of a thermal power plant or the header weld of the piping of a thermal power plant, and the base metal part around the header hole of the above pipe alignment or the above piping. Note that the first evaluation site may be either the pipe alignment of a thermal power plant or the header weld of the piping of a thermal power plant, or the base metal part around the header hole of the above pipe alignment or the above piping. In the following description, the pipe alignment and piping of a thermal power plant may sometimes be simply referred to as piping.

[0020] FIG. 3 is an example of a cross-sectional view in the vicinity of the nozzle welding part of a pipe. In the example of FIG. 3, the first evaluation part 5 according to the present embodiment is the nozzle welding part 41 and the base material part (the base material part around the nozzle hole) 23 around the nozzle hole 21 of the pipe 10 (main pipe 20). The nozzle welding part 41 of the pipe of a thermal power generation plant may be, for example, a nozzle welding part for aligning boiler pipes, or may be a nozzle welding part of a pipe of a thermal power generation plant other than for aligning boiler pipes. The base material part 23 around the nozzle hole of the pipe of a thermal power generation plant may be, for example, a part where the nozzle hole 21 is formed in the main pipe 20 for aligning boiler pipes, or may be a part where the nozzle hole 21 is formed in the main pipe 20 of a boiler pipe other than for aligning boiler pipes.

[0021] In step S1 of inputting data regarding the first evaluation part 5, various data regarding the first evaluation part 5 may be input from the input part 103, or the data stored in the storage part 105 may be read out and input to the processing part 101.

[0022] The various data regarding the first evaluation part 5 input to the processing part 101 in step S1 of inputting data regarding the first evaluation part 5 include data regarding the nozzle 30 related to the first evaluation part 5 that is the object of life evaluation, evaluation pressure, evaluation temperature, steel material type, etc. The data regarding the nozzle 30 related to the first evaluation part 5 includes the nozzle type, main pipe dimensions, and nozzle dimensions, which will be described later. Here, the evaluation pressure is the internal pressure of the pipe 10 related to the first evaluation part 5, and the evaluation temperature is the temperature of the pipe 10 related to the first evaluation part 5. Also, the steel material type is, for example, the type of the material of the pipe 10 related to the first evaluation part, such as improved 2Cr steel, improved 9Cr steel, 12Cr steel, etc., which are classified as high-strength heat-resistant steel.

[0023] (Regarding the type of nozzle) The pipe base type included in the data related to the pipe base 30 related to the first evaluation part 5 is information indicating what type of pipe base is classified from at least any one of the positional relationship between the main pipe 20 and the connecting pipe (pipe base) 30, whether the connecting pipe 30 penetrates the main pipe 20, or the shape of the pipe base welded part 41. Figures 4A to 4F are diagrams showing examples of pipe base types classified from the above viewpoints. The pipe base 30 (pipe base 31) as shown in Figure 4A is referred to as type A, the pipe base 30 (pipe base 32) as shown in Figure 4B is referred to as type B, and the pipe base 30 (pipe base 33) as shown in Figure 4C is referred to as type C. The pipe base 30 (pipe base 34) as shown in Figure 4D is referred to as type E, the pipe base 30 (pipe base 35) as shown in Figure 4E is referred to as type F, and the pipe base 30 (pipe base 36) as shown in Figure 4F is referred to as type G.

[0024] In this embodiment, as a classification axis of the pipe base type, for example, it is classified by the positional relationship between the main pipe 20 and the connecting pipe (pipe base 30). In this case, the pipe base type is classified by whether it is a set-on pipe base or a set-in pipe base. The set-on pipe base is a type of pipe base in which the connecting pipe (pipe base 30) rides on the main pipe 20, such as the type A pipe base 31 shown in Figure 4A. The set-in pipe base is a type of pipe base in which, for example, as in the type B pipe base 32 shown in Figure 4B, a countersink process is performed on the main pipe 20 and the connecting pipe is inserted into the countersink hole.

[0025] In this embodiment, as a classification axis of the pipe base type, for example, it is classified by whether the connecting pipe penetrates the main pipe. For example, in the type F pipe base 35 shown in Figure 4E, the connecting pipe (pipe base 35) penetrates the main pipe 20, and in the other type pipe bases 30 shown in Figures 4A to 4D and 4F, the connecting pipe (pipe base 30) does not penetrate the main pipe 20.

[0026] In this embodiment, as a classification axis of the pipe base type, for example, it may be classified by the shape of the pipe base welded part or the groove shape. In this embodiment, as a classification axis of the pipe base type, for example, it may be classified according to the depth of the countersink hole, the taper angle, etc. in the built-in pipe base. For example, in the B-type pipe base 32 shown in FIG. 4B, the depth of the countersink hole is relatively shallow, and in the G-type pipe base 36 shown in FIG. 4F, the depth of the countersink hole is relatively deep.

[0027] (Step S3 of calculating the life evaluation stress) Step S3 of calculating the life evaluation stress according to this embodiment is a step of calculating the life evaluation stress σ used for evaluating the life of the first evaluation part 5 based on various data input in step S1 of inputting data related to the first evaluation part.

[0028] As a result of intensive studies by the inventors, for example, with respect to the stress serving as a reference for the life evaluation stress σ, such as the outer surface hoop stress σθsurface of the main pipe 20, it has been found that the life evaluation stress can be easily calculated by multiplying by a stress coefficient β determined in advance based on the pipe base type, the main pipe dimensions, the pipe base dimensions, the evaluation pressure, and the evaluation temperature, which will be described later.

[0029] FIG. 5 is an example of a graph showing the relationship between the stress coefficient β and the variable βx. The stress coefficient β according to this embodiment is obtained as a value proportional to the variable βx described below. The variable βx is represented by a function having, for example, as in the following formula (1), the outer diameter D of the main pipe 20, the outer diameter d of the pipe base 30, the wall thickness T of the main pipe 20, the wall thickness t of the pipe base, the depth z of the countersink hole, the tip angle h, the weld leg length b0, etc. as variables. These variables are the data input in step S1 of inputting data related to the first evaluation part 5. βx = f(D, d, T, t, z, h, b0) ···(1)

[0030] Note that the function for obtaining the variable βx is determined in advance for each of the above-described pipe base types and for each of the parts of the first evaluation part (the pipe base welding part 41 and the base material part 23 around the pipe base hole), and is stored in the storage part 105. Also, regarding the relationship between the stress coefficient β and the variable βx as shown in FIG. 5, it is determined in advance for each of the above-described pipe base types and for each of the parts of the first evaluation part (the pipe base welding part 41), and is stored in the storage part 105. Regarding the part of the first evaluation part (the base material part 23 around the pipe base hole), a stress coefficient and variables corresponding to the outer diameter and wall thickness of the header pipe and the pipe base are determined in advance and stored in the storage part 105. In step S3 of calculating the life evaluation stress, the first stress calculation unit 111 in the processing unit 101 reads from the storage unit 105 the function for obtaining the variable βx and information regarding the relationship between the stress coefficient β and the variable βx, based on the pipe base type and the part of the first evaluation part input in step S1 where data regarding the first evaluation part is input. Then, the first stress calculation unit 111 calculates the variable βx and the stress coefficient β.

[0031] Next, the first stress calculation unit 111 calculates a stress that serves as a reference for the life evaluation stress σ, such as the outer surface hoop stress σθsurface of the header pipe 20, from the evaluation pressure input in step S1 where data regarding the first evaluation part is input. Then, the first stress calculation unit 111 calculates the life evaluation stress σ by multiplying the calculated stress by the stress coefficient β, for example, as in the following formula (2). σ = σθsurface × β ···(2)

[0032] (Regarding the correction coefficient Ψ) In step S3 of calculating the life evaluation stress, the first stress calculation unit 111 may further calculate the life evaluation stress σ in consideration of a correction coefficient Ψ determined in advance based on the inspection result of the pipe 10 and the internal pressure creep test result, for example, as in the following formula (3). Note that the correction coefficient Ψ is a correction coefficient determined in advance based on the inspection result of the pipe 10 and the internal pressure creep test result in order to improve the accuracy of the life evaluation regarding the first evaluation part obtained based on the life evaluation stress σ. The correction coefficient Ψ is stored in the storage part 105. σ = σθsurface × β × Ψ ···(3)

[0033] As described above, in the life evaluation system 100 according to this embodiment, the first stress calculation unit 111 calculates the life evaluation stress σ in consideration of the stress coefficient β determined in advance based on the pipe base type, the main pipe dimensions, the pipe base dimensions, the evaluation pressure, and the evaluation temperature. Thereby, the stress coefficient β can be immediately obtained from the pipe base type, the main pipe dimensions, the pipe base dimensions, the evaluation pressure, and the evaluation temperature, and the life evaluation stress σ can be easily calculated by multiplying the obtained stress coefficient β by the stress serving as the reference for the life evaluation stress σ. Thereby, the life of the pipe base 30 can be evaluated relatively accurately in a short time.

[0034] In the life evaluation system 100 according to this embodiment, the first stress calculation unit 111 may calculate the life evaluation stress σ in consideration of the correction coefficient Ψ determined in advance based on the inspection result of the pipe 10 and the internal pressure creep test result. Thereby, the accuracy of the life evaluation of the pipe base 30 can be improved.

[0035] In the life evaluation system 100 according to this embodiment, by considering the pipe base type as described above, the accuracy of the life evaluation of the pipe base 30 can be improved.

[0036] (Step S5 of evaluating the life) Step S5 of evaluating the life according to this embodiment is a step of evaluating the life of the first evaluation site 5 based on the life evaluation stress σ calculated in step S3 of calculating the life evaluation stress. In step S5 of evaluating the life, the first life evaluation unit 113 in the processing unit 101 calculates the life of the first evaluation site 5 based on the life evaluation stress σ calculated in step S3 of calculating the life evaluation stress. Specifically, the first life evaluation unit 113 calculates the life by obtaining the creep damage rate of the first evaluation site 5 for each minute time based on the life evaluation stress σ. Here, the first life evaluation unit 113 may calculate the life of the first evaluation part 5 based on the life evaluation stress σ obtained by the above-described formula (3). Note that the first life evaluation unit 113 may also calculate the life of the first evaluation part 5 based on the life evaluation stress σ obtained by the above-described formula (2).

[0037] The life calculated in step S5 for evaluating the life is at least one of the initial crack generation life of the pipe base welding end part 41a (see FIG. 3) related to the first evaluation part 5, the life of the base material part 23 around the pipe base hole related to the first evaluation part 5, or the fracture life of the pipe base welding part 41 related to the first evaluation part 5. In the following description, the life calculated in step S5 for evaluating the life is the initial crack generation life of the pipe base welding end part 41a (see FIG. 3) related to the first evaluation part 5, the crack propagation life from the pipe base welding end part 41a or the unwelded part 42a of the internal pipe base welding (see FIG. 3), the life of the base material part 23 around the pipe base hole related to the first evaluation part 5, and the fracture life of the pipe base welding part 41 related to the first evaluation part 5.

[0038] As described above, the life evaluation system 100 according to the present embodiment includes a first stress calculation unit 111 that calculates a life evaluation stress σ used for evaluating the life of the first evaluation part 5 based on the pipe base type, the mother pipe dimension, the pipe base dimension, the evaluation pressure, the evaluation temperature, and the steel material type related to the first evaluation part 5, and a first life evaluation unit 113 that evaluates the life of the first evaluation part 5 based on the life evaluation stress σ. Thereby, when evaluating the life of the first evaluation part 5, the life of the piping 10 including the pipe base 30 can be evaluated with relatively high accuracy without newly performing the FEM elastic creep analysis. Therefore, according to the life evaluation system 100 according to the present embodiment, the life of the piping 10 including the pipe base 30 can be evaluated with relatively high accuracy in a short time.

[0039] In the life evaluation system 100 according to the present embodiment, the first life evaluation unit 113 calculates at least one of the initial crack generation life of the pipe base welding end part 41a related to the first evaluation part 5, the life of the base material part 23 around the pipe base hole related to the first evaluation part 5, or the fracture life of the pipe base welding part 41 related to the first evaluation part 5 based on the life evaluation stress σ. This enables life evaluation corresponding to the form of damage in the pipe 10 including the pipe base 30.

[0040] In the life evaluation system 100 according to this embodiment, the first life evaluation unit 113 calculates the crack propagation life from the pipe base weld termination part 41a or the pipe base internal unwelded part 42a (see FIG. 3) related to the first evaluation part 5 based on the life evaluation stress σ. This enables life evaluation based on the crack generated from the pipe base weld termination part 41a.

[0041] The life evaluation method using the life evaluation system 100 according to this embodiment includes a step S3 of calculating the life evaluation stress and a step S5 of evaluating the life. As described above, this enables relatively accurate evaluation of the life of the pipe base 30 without newly performing FEM elastic creep analysis when evaluating the life of the first evaluation part 5. Therefore, according to the life evaluation method using the life evaluation system 100 according to this embodiment, the life of the pipe 10 including the pipe base 30 can be evaluated relatively accurately in a short time.

[0042] (Step S7 of outputting the result of life evaluation) Step S7 of outputting the result of life evaluation according to this embodiment is a step of outputting the life of the first evaluation part 5 calculated in step S5 of evaluating the life to the output unit 107 as the result of life evaluation. In step S7 of outputting the result of life evaluation, the first life evaluation unit 113 generates display data for displaying the life of the first evaluation part 5 calculated in step S5 of evaluating the life at the output unit 107 and outputs it to the output unit 107. Note that the first life evaluation unit 113 may generate the life of the first evaluation part 5 calculated in step S5 of evaluating the life as, for example, voice data and output it to the output unit 107. That is, the data output in step S7 of outputting the result of life evaluation is not limited to display data. FIG. 6 is an example of a table showing the result of life evaluation of the first evaluation part 5 displayed at the output unit 107.

[0043] As shown in FIG. 6, the result 70 of the life evaluation of the first evaluation part 5 displayed at the output part 107 includes various data 71 input in step S1 for inputting data related to the first evaluation part 5 and the result 73 of the life evaluation of the first evaluation part 5. As shown in FIG. 6, the result 73 of the life evaluation of the first evaluation part 5 includes the initial crack generation life 731 of the nozzle weld stop end part 41a related to the first evaluation part 5, the crack propagation life 733 from the nozzle weld stop end part 41a or the unwelded part 42a of the nozzle internal weld (see FIG. 3), the life 735 of the base material part 23 around the nozzle hole related to the first evaluation part 5, and the fracture life 737 of the nozzle weld part 41 related to the first evaluation part 5.

[0044] Note that the evaluation stress σ1 shown in the result 73 of the life evaluation of the first evaluation part 5 is the life evaluation stress σ used to obtain the fracture life 737 of the nozzle weld part 41 related to the first evaluation part 5. The evaluation stress σ2 shown in the result 73 of the life evaluation of the first evaluation part 5 is the life evaluation stress σ used to obtain the initial crack generation life 731 of the nozzle weld stop end part 41a related to the first evaluation part 5. The evaluation stress σ3 shown in the result 73 of the life evaluation of the first evaluation part 5 is the life evaluation stress σ used to obtain the crack propagation life 733 from the nozzle weld stop end part 41a. The evaluation stress σ4 shown in the result 73 of the life evaluation of the first evaluation part 5 is the life evaluation stress σ used to obtain the life 735 of the base material part 23 around the nozzle hole related to the first evaluation part 5.

[0045] (Regarding the life evaluation related to the second evaluation part in the life evaluation system 100) Furthermore, the life evaluation in the life evaluation system 100 according to the present embodiment will be described. Thermal stress, stress due to internal pressure, bending stress due to self-weight, etc., i.e., the stress generated by external forces, acts on the base material part of the pipe 10 of the thermal power plant, the longitudinal welded part of the pipe 10, and the circumferential welded part of the pipe 10. Since this thermal stress causes a relaxation phenomenon in which it decreases over time, in order to grasp the appropriate life, it is necessary to conduct an evaluation considering this relaxation phenomenon. Conventionally, FEM elastic creep analysis has been carried out for creep damage evaluation (life evaluation) considering the relaxation phenomenon, which required a great deal of time and effort. In the following description, when the base material part of the pipe 10 of the thermal power plant, the longitudinal welded part of the pipe 10, or the circumferential welded part of the pipe 10 is the object of life evaluation, these parts are referred to as the second evaluation parts.

[0046] Based on the initial stress at the time of design of the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type, the initial stress for life evaluation used for evaluating the life of the second evaluation part is calculated. Based on the calculated initial stress for life evaluation, by calculating the time history of the life consumption rate of the second evaluation part considering the stress relaxation of the thermal expansion stress in the second evaluation part, the life of the second evaluation part can be evaluated. Here, regarding the initial stress at the time of design of the second evaluation part, by using the analysis results of a general-purpose pipe stress analysis system commonly used in the design of the pipe 10, the life of the second evaluation part can be evaluated with relatively high accuracy without performing FEM elastic creep analysis for life evaluation considering the relaxation phenomenon. That is, since the analysis results of the general-purpose pipe stress analysis system are obtained at the time of design of the pipe 10, if the initial stress at the time of design of the second evaluation part included in this analysis result is obtained, the initial stress for life evaluation used for evaluating the life of the second evaluation part can be easily calculated. Therefore, the life evaluation system 100 according to the present embodiment evaluates the life of the second evaluation part as follows.

[0047] FIG. 7 is a flowchart schematically showing the life evaluation procedure for the second evaluation part of the life evaluation system 100 according to the present embodiment. The life evaluation method using the life evaluation system 100 according to this embodiment includes a step S11 of inputting data related to the second evaluation site, a step S12 of inputting an initial stress, a step S13 of calculating a life evaluation stress, a step S14 of calculating a time history, a step S15 of evaluating a life, and a step S17 of outputting the result of the life evaluation.

[0048] (Step S11 of inputting data related to the second evaluation site) In the step S11 of inputting data related to the second evaluation site according to this embodiment, it is a step of inputting various data related to the second evaluation site into the processing unit 101. Here, the second evaluation site according to this embodiment is the base material part of the pipe 10 of the thermal power generation plant, the longitudinal welded part of the pipe 10, and the circumferential welded part of the pipe 10. Note that the second evaluation site may be any one of the base material part of the pipe 10 of the pipe of the thermal power generation plant, the longitudinal welded part of the pipe 10, or the circumferential welded part of the pipe 10. The pipe 10 may be a pipe for boiler tube alignment, or a boiler pipe other than boiler tube alignment. The pipe 10 may be the main pipe 20 or the pipe stand 30.

[0049] In the step S11 of inputting data related to the second evaluation site, various data related to the second evaluation site may be input from the input unit 103, or the data stored in the storage unit 105 may be read out and input to the processing unit 101.

[0050] Various data related to the second evaluation site input to the processing unit 101 in the step S11 of inputting data related to the second evaluation site includes data related to the dimensions of the pipe 10, the evaluation pressure, the evaluation temperature, the steel material type, etc., which are related to the second evaluation site that is the object of life evaluation. Here, the evaluation pressure is the internal pressure of the pipe 10 related to the second evaluation site, and the evaluation temperature is the temperature of the pipe 10 related to the second evaluation site. Also, the steel material type is classified into, for example, improved 2Cr steel, improved 9Cr steel, 12Cr steel, etc. classified as high-strength heat-resistant steel. 2It refers to the type of material of the pipe 10 related to the evaluation site.

[0051] (Step S12 of inputting the initial stress) In the present embodiment, step S12 of inputting the initial stress is a step of inputting the initial stress at the time of designing the second evaluation site. In step S12 of inputting the initial stress, the initial stress at the time of designing the second evaluation site is acquired from the analysis result of the general-purpose piping stress analysis system obtained at the time of designing the pipe 10. For example, if the analysis result of the general-purpose piping stress analysis system or the initial stress at the time of designing the second evaluation site included in the analysis result is stored in the storage unit 105 in advance, in step S12 of inputting the initial stress, the initial stress at the time of designing the second evaluation site can be read out and acquired from the storage unit 105.

[0052] (Step S13 of calculating the life evaluation stress) In the present embodiment, step S13 of calculating the life evaluation stress is a step of calculating the initial stress (life evaluation initial stress) of the life evaluation stress σ used for evaluating the life of the second evaluation site based on various data input in step S11 of inputting data related to the second evaluation site and various data input to the processing unit 101 in step S12 of inputting the initial stress. In step S13 of calculating the life evaluation stress, the second stress calculation unit 121 of the processing unit 101 calculates the life evaluation initial stress from the initial stress at the time of designing the second evaluation site in consideration of the dimensional data of the pipe 10 related to the second evaluation site among various data input in step S11 of inputting data related to the second evaluation site and various data input to the processing unit 101 in step S12 of inputting the initial stress.

[0053] (Step S14 of calculating the time history) In the present embodiment, step S14 of calculating the time history is a step of calculating the time history of the stress relaxation trajectory of the second evaluation site (time history of the life evaluation stress σ) in consideration of the stress relaxation of the thermal expansion stress in the second evaluation site based on the life evaluation initial stress calculated in step S13 of calculating the life evaluation stress. FIG. 8 is an example of a graph showing the time history of the life evaluation stress σ and the change over time of the cumulative life consumption rate. In the graph shown in FIG. 8, the horizontal axis is a logarithmic axis with respect to the elapsed time. In step S14 of calculating the time history, the time history calculation unit 122 of the processing unit 101 calculates the stress relaxation trajectory as a time history in consideration of the primary creep 91 with a relatively high speed and the secondary creep 92 with a relatively low speed.

[0054] (Step S15 of evaluating the life) Step S15 of evaluating the life according to the present embodiment is a step of calculating the life (cumulative life consumption rate) related to the second evaluation site based on the time history of the life evaluation stress σ calculated in step S14 of calculating the time history. In step S15 of evaluating the life, the second life evaluation unit 123 of the processing unit 101 calculates the cumulative life consumption rate by calculating the creep damage degree for each minute time based on the time history of the life evaluation stress σ calculated in step S14 of calculating the time history. The cumulative life consumption rate is set to 0 for the initial state of the pipe 10 where creep damage has not accumulated, and 1 for the state where creep damage has accumulated and the pipe 10 breaks.

[0055] (Step S17 of outputting the result of life evaluation) Step S17 of outputting the result of life evaluation according to the present embodiment is a step of outputting the life of the second evaluation site calculated in step S15 of evaluating the life to the output unit 107 as the result of life evaluation. In step S17 of outputting the result of life evaluation, the second life evaluation unit 123 generates display data for displaying the life of the second evaluation site calculated in step S15 of evaluating the life on the output unit 107 and outputs it to the output unit 107. Note that the second life evaluation unit 123 may generate the life of the second evaluation site calculated in step S15 of evaluating the life as, for example, voice data and output it to the output unit 107. That is, the data output in step S17 of outputting the result of life evaluation is not limited to display data. FIG. 9 is an example of a table showing the result of life evaluation of the second evaluation site displayed on the output unit 107.

[0056] As shown in FIG. 9, the result 80 of the life evaluation of the second evaluation part displayed in the output part 107 includes various data 81 input in the step S11 of inputting data related to the second evaluation part, data 82 such as the initial stress at the time of design of the second evaluation part obtained in the step S12 of inputting the initial stress, and the result 83 of the life evaluation of the second evaluation part. In the example shown in FIG. 9, as the result 83 of the life evaluation of the second evaluation part, for example, if the second evaluation part is the welded part of the welded joint, the life of the circumferential welded part of this welded joint is included, and if the second evaluation part is the base material of the pipe 10, the life of the base material part of this pipe 10 is included.

[0057] Note that when the second evaluation part is a bend part such as an elbow or a bent pipe, the second stress calculation part 121 may calculate the initial stress for life evaluation in consideration of the circumferential wall thickness distribution in the elbow or the bend part. When the second evaluation part is an elbow or a bend part, the time history calculation part 122 may calculate the above-mentioned time history in consideration of the wall thickness distribution. That is, the elbows and bends of the pipes 10 in the thermal power generation plant are manufactured by bending straight pipes. Therefore, there is a circumferential wall thickness distribution in the elbows and bends. As described above, by considering the circumferential wall thickness distribution in the elbows and bends, the accuracy of the life evaluation of the second evaluation part can be improved.

[0058] (Regarding the type of steel material) In some embodiments, the type of steel material related to the pipe 10 has been described as high-strength heat-resistant steel, but it is not limited to this. That is, in some embodiments, each part of the pipe 10 may be formed of, for example, high-chromium steel containing about 9 to 12 mass% of chromium or low-alloy steel containing about 1 to 3 mass% of chromium. In some embodiments, the type of steel material related to the pipe 10 may be any of various steel materials used in the creep temperature range.

[0059] The present disclosure is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0060] The content described in each of the above embodiments can be understood as follows, for example. (1) The life evaluation system 100 according to at least one embodiment of the present disclosure uses at least one of the nozzle weld portion 41 of the nozzle or the pipe 10 of the thermal power generation plant, or the base material portion 23 around the nozzle hole of the nozzle or the pipe 10 as the first evaluation site 5 for evaluating the life, and based on the nozzle type, header pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the first evaluation site 5, a first stress calculation unit 111 that calculates a life evaluation stress σ used for evaluating the life of the first evaluation site 5, and a first life evaluation unit 113 that evaluates the life of the first evaluation site 5 based on the life evaluation stress σ.

[0061] As a result of intensive studies by the inventors, FEM elastic creep analysis was previously performed on a plurality of patterns in which the nozzle type and the dimensions of each part of the nozzle are different, and based on the analysis results, the life evaluation stress σ was parameterized, so that the life evaluation stress σ can be easily calculated from the nozzle type, header pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type. Thereby, when evaluating the life of the first evaluation site 5, the life of the pipe 10 including the nozzle 30 can be evaluated with relatively high accuracy without newly performing FEM elastic creep analysis. Therefore, according to the configuration of the above (1), the life of the pipe 10 including the nozzle 30 can be evaluated with relatively high accuracy in a short time.

[0062] (2) In some embodiments, in the configuration of the above (1), the first life evaluation unit 113 may calculate at least one of the initial crack generation life of the nozzle weld end portion 41a related to the first evaluation site 5, the life of the base material portion 23 around the nozzle hole related to the first evaluation site 5, or the fracture life of the nozzle weld portion 41 related to the first evaluation site 5 based on the life evaluation stress σ.

[0063] According to the configuration of the above (2), life evaluation corresponding to the form of damage in the pipe 10 including the nozzle 30 can be performed.

[0064] (3) In some embodiments, in the configuration of (2) above, the first life evaluation unit 113 may calculate the crack propagation life from the pipe base welding stop end portion 41a or the unwelded portion 42a inside the pipe base (see FIG. 3) related to the first evaluation site 5 based on the life evaluation stress σ.

[0065] According to the configuration of (3) above, life evaluation can be performed for cracks generated from the pipe base welding stop end portion 41a or the unwelded portion 42a inside the pipe base (see FIG. 3).

[0066] (4) In some embodiments, in any of the configurations of (1) to (3) above, the first stress calculation unit 111 may calculate the life evaluation stress σ in consideration of a stress coefficient β determined in advance based on the pipe base type, the mother pipe dimensions, the pipe base dimensions, the evaluation pressure, and the evaluation temperature.

[0067] According to the configuration of (4) above, the stress coefficient β can be immediately obtained from the pipe base type, the mother pipe dimensions, the pipe base dimensions, the evaluation pressure, and the evaluation temperature, and the life evaluation stress σ can be easily calculated by multiplying the obtained stress coefficient β by the stress serving as the reference for the life evaluation stress σ. Thereby, the life of the piping 10 including the pipe base 30 can be evaluated relatively accurately in a short time.

[0068] (5) In some embodiments, in the configuration of (4) above, the first stress calculation unit 111 may calculate the life evaluation stress σ in consideration of a correction coefficient Ψ determined in advance based on the inspection result of the piping 10 and the internal pressure creep test result.

[0069] According to the configuration of (5) above, the accuracy of the life evaluation of the piping 10 including the pipe base 30 can be improved.

[0070] (6) In some embodiments, in any of the configurations of (1) to (5) above, the pipe base type may be classified from at least any one of the viewpoints of the positional relationship between the mother pipe 20 and the connecting pipe (pipe base 30), whether the connecting pipe (pipe base 30) penetrates the mother pipe 20, or the shape of the pipe base welding portion 41.

[0071] According to the configuration of (6) above, by considering the pipe support type classified from the above viewpoints, the accuracy of the life evaluation of the piping 10 including the pipe support 30 can be improved.

[0072] (7) In some embodiments, in any of the configurations of (1) to (6) above, at least one of the base material part of the piping 10, the longitudinal welded part of the piping 10, or the circumferential welded part of the piping 10 is used as a second evaluation part that is the object of life evaluation. A second stress calculation unit 121 that calculates an initial stress for life evaluation used for evaluating the life of the second evaluation part based on the initial stress at the time of design of the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type; A time history calculation unit 122 that calculates a time history of the stress relaxation trajectory of the second evaluation part in consideration of the stress relaxation of the thermal expansion stress in the second evaluation part based on the initial stress for life evaluation; and a second life evaluation unit 123 that evaluates the life of the second evaluation part based on the time history. It is preferable to include.

[0073] According to the configuration of (7) above, based on the initial stress at the time of design of the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type, an initial stress for life evaluation used for evaluating the life of the second evaluation part is calculated. By calculating the time history of the life consumption rate of the second evaluation part in consideration of the stress relaxation of the thermal expansion stress in the second evaluation part based on the calculated initial stress for life evaluation, the life of the second evaluation part can be evaluated.

[0074] (8) In some embodiments, in the configuration of (7) above, when the second evaluation part is an elbow or a bend part, the second stress calculation unit 121 preferably calculates the initial stress for life evaluation in consideration of the circumferential wall thickness distribution in the elbow or the bend part. When the second evaluation part is an elbow or a bend part, the time history calculation unit 122 preferably calculates the time history in consideration of the wall thickness distribution.

[0075] For elbows of the piping 10 in a thermal power plant and bends such as bent pipes, they are manufactured by bending straight pipes. Therefore, there is a circumferential wall thickness distribution in the bend part. According to the configuration of (8) above, by considering the circumferential wall thickness distribution in the bend portion, the accuracy of the life evaluation of the second evaluation site can be improved.

[0076] (9) In some embodiments, in any of the configurations of (1) to (8) above, the steel material type may preferably include high-chromium steel, which is high-strength heat-resistant steel.

[0077] Like the configuration of (9) above, the configurations of (1) to (8) above are suitable for the life evaluation of the piping 10 of a thermal power generation plant formed of high-chromium steel.

[0078] (10) The life evaluation method according to at least one embodiment of the present disclosure uses, as a first evaluation site 5 for which the life is to be evaluated, at least one of the nozzle weld portion 41 of the piping 10 of a thermal power generation plant or the base material portion 23 around the nozzle hole of the piping 10, and calculates a life evaluation stress σ to be used for the life evaluation of the first evaluation site 5 based on the nozzle type, header pipe dimensions, nozzle dimensions, evaluation pressure, evaluation temperature, and steel material type related to the first evaluation site 5 (step S3 of calculating the life evaluation stress σ), and based on the life evaluation stress σ, evaluates the life of the first evaluation site 5 (step S5 of evaluating the life).

[0079] According to the method of (10) above, as described above, when evaluating the life of the first evaluation site 5, the life of the nozzle can be evaluated with relatively high accuracy without newly performing FEM elastic creep analysis. Therefore, according to the method of (10) above, the life of the piping 10 including the nozzle 30 can be evaluated with relatively high accuracy in a short time.

Description of Reference Numerals

[0080] 5 First evaluation site 10 Piping 20 Header pipe 21 Nozzle hole 23 Base material portion around the nozzle hole 30 Nozzle (connecting pipe) 41 Nozzle weld portion 41a Nozzle weld termination end 42a Unwelded portion of the internal weld of the nozzle 100 Life evaluation system 101 Processing unit 103 Input unit 105 Memory unit 107 Output unit 111 First stress calculation unit 113 First life evaluation unit 121 Second stress calculation unit 122 Time history calculation unit 123 Second life evaluation unit

Claims

1. At least one of the pipe alignment or the pipe base welding part of the piping in a thermal power plant, or the base material part around the pipe base hole of the pipe alignment or the piping is set as a first evaluation part to be the target of life evaluation, and based on the pipe base type, the main pipe dimension, the pipe base dimension, the evaluation pressure, the evaluation temperature, and the steel material type related to the first evaluation part, a first stress calculation part that calculates a life evaluation stress used for the life evaluation of the first evaluation part, and a first life evaluation part that evaluates the life of the first evaluation part based on the life evaluation stress are provided, the first stress calculation part calculates the life evaluation stress in consideration of a stress coefficient determined in advance based on the pipe base type, the main pipe dimension, the pipe base dimension, the evaluation pressure, and the evaluation temperature life evaluation system.

2. The first life evaluation part calculates at least one of the initial crack generation life of the pipe base welding end part related to the first evaluation part, the life of the base material part around the pipe base hole related to the first evaluation part, or the fracture life of the pipe base welding part related to the first evaluation part based on the life evaluation stress The life evaluation system according to claim 1.

3. The first life evaluation part calculates the crack propagation life from the pipe base welding end part related to the first evaluation part based on the life evaluation stress The life evaluation system according to claim 2.

4. The first stress calculation part calculates the life evaluation stress in consideration of a correction coefficient determined in advance based on the inspection result of the piping and the internal pressure creep test result The life evaluation system according to any one of claims 1 to 3.

5. The pipe base type is classified from at least one of the positional relationship between the main pipe and the connecting pipe, whether the connecting pipe penetrates the main pipe, or the shape of the pipe base welding part The life evaluation system according to any one of claims 1 to 3.

6. At least one of the base material part of the piping, the longitudinal welding part of the piping, or the circumferential welding part of the piping is set as a second evaluation part to be the target of life evaluation, and based on the initial stress at the time of design of the second evaluation part, the type of the second evaluation part, the evaluation pressure, the evaluation temperature, and the steel material type, a second stress calculation part that calculates a life evaluation initial stress used for the life evaluation of the second evaluation part, and a time history calculation part that calculates the time history of the stress relaxation trajectory of the second evaluation part in consideration of the stress relaxation of the thermal expansion stress in the second evaluation part based on the life evaluation initial stress A second life evaluation unit that evaluates the life of the second evaluation site based on the time history; Comprising; The life evaluation system according to any one of claims 1 to 3.

7. When the second stress calculation unit is an elbow or a bend part of the second evaluation site, the life evaluation initial stress is calculated in consideration of the circumferential wall thickness distribution in the elbow or the bend part; When the second evaluation site is the elbow or the bend part, the time history calculation unit calculates the time history in consideration of the wall thickness distribution; The life evaluation system according to claim 6.

8. The steel material type includes high-chromium steel which is high-strength heat-resistant steel; The life evaluation system according to any one of claims 1 to 3.

9. Taking at least one of the pipe alignment of a thermal power plant or the pipe base welding part of the pipe, or the base metal part around the pipe base hole of the pipe alignment or the pipe as the first evaluation site for life evaluation, and based on the pipe base type, the mother pipe dimension, the pipe base dimension, the evaluation pressure, the evaluation temperature, and the steel material type related to the first evaluation site, calculating the life evaluation stress used for evaluating the life of the first evaluation site; Evaluating the life of the first evaluation site based on the life evaluation stress; Comprising; In the step of calculating the life evaluation stress, the life evaluation stress is calculated in consideration of a stress coefficient determined in advance based on the pipe base type, the mother pipe dimension, the pipe base dimension, the evaluation pressure, and the evaluation temperature; Life evaluation method.

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