CN113434985B - State evaluation method for tube seat and connecting tube of steam-water separator of supercritical or ultra-supercritical boiler - Google Patents
State evaluation method for tube seat and connecting tube of steam-water separator of supercritical or ultra-supercritical boiler Download PDFInfo
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Abstract
A state evaluation method for a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler comprises the following steps of; 1) Explicitly evaluating the object and the basic information; 2) Defining detailed evaluation points; 3) The specific stage of the full-operation life cycle of the object is clearly evaluated; 4) Calculating a state factor; 5) Calculating a correction factor; 6) Making a metal inspection scheme and implementing the scheme; 7) Obtaining a metal inspection result; 8) Evaluating point states; 9) Evaluating the state of an evaluation object; 10 Filing and feeding back the evaluation result. The invention can help technical boilers or metal professionals in thermal power plants to better formulate maintenance strategies.
Description
Technical Field
The invention belongs to the technical field of equipment state evaluation of thermal power plants, and particularly relates to a state evaluation method for a tube seat and a connecting tube of a steam-water separator of a supercritical or ultra-supercritical boiler.
Background
The supercritical or ultra-supercritical boiler steam-water separator is an important component of a boiler system of a thermal power plant, and in recent years, a large-scale high-parameter supercritical or ultra-supercritical thermal power unit frequently participates in power grid peak shaving operation, so that the supercritical or ultra-supercritical boiler steam-water separator is in a worse working condition in the operation process and is easily influenced by the action of heat alternating load. Particularly, the steam-water separator tube seat and the connecting tube area have larger stress concentration phenomenon, the stress concentration is more obvious as the number of the connecting tubes is larger, and the welding seams at the tube seat are dense, so that the structural state of the welding seams is worsened and the structural embrittlement is increased under the influence of high-temperature high-pressure variable load. In addition, since the supercritical or ultra supercritical boiler steam-water separator tube seat and the adapter tube are located outside the boiler, if a failure occurs, a serious safety accident may be caused, and thus it is necessary to evaluate the state of the supercritical or ultra supercritical boiler steam-water separator tube seat and the adapter tube more accurately.
For supercritical or ultra supercritical boiler steam-water separators, stress analysis and stress distribution based on transient thermosetting coupling of tangential miter joint structures at steam inlets of steam-water separators by ANSYS software have been reported in the literature, such as literature "steam inlet tangential miter joint structure stress analysis research at steam-water separator start-up stage, power station auxiliary, 2013 (2)", thermal stress concentration near the long axis of connecting pipe elliptical holes by finite element method analysis, such as literature "600MW supercritical boiler steam-water separator internal pressure stress finite element analysis, boiler technology, 2009 (1)", and literature "medium pressure steam-water separator external wall take-over fillet crack cause discussion, such as literature" medium pressure steam-water separator external wall take-over fillet crack discussion and treatment, noble chemical, 2012 (2) ". The state analysis or life assessment of the steam-water separator tube seat and the connecting tube is particularly reported. The steam-water separator tube seat and the connecting tube are subjected to stress analysis or service life assessment, and the following conditions are required: the personnel to be evaluated have abundant mathematical analysis basic knowledge, metal material basic knowledge, mechanical calculation knowledge, life evaluation knowledge and experience; complete design data and design data need to be collected; complete operation history data needs to be collected; complete and comprehensive metal inspection related data needs to be collected; a stress field and temperature field model is required to be constructed; comprehensive laboratory analysis data of samples of the same material are required as a reference group, etc. The complex conditions determine that the development of stress analysis, life loss calculation and other technologies is limited to professional technical institutions and personnel, and the collection of basic data and data, complete and comprehensive metal inspection and laboratory analysis can lead to increased maintenance costs and labor costs of power plants.
Therefore, a method with universality is needed to be found, and the state evaluation can be carried out on the tube seat and the takeover of the steam-water separator of the supercritical or ultra-supercritical boiler only by obtaining the existing metal test data without the need of having abundant mathematical analysis basic knowledge, metal material basic knowledge, mechanical calculation knowledge, service life evaluation knowledge and experience by an evaluator and without bearing additional test cost, so that the maintenance strategy can be directly formulated by the technicians of a thermal power plant.
Disclosure of Invention
In order to overcome the technical problems, the invention aims to provide a state evaluation method for a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler, which helps technical boilers or metal professionals of a thermal power plant to better formulate a maintenance strategy.
In order to achieve the above purpose, the technical scheme adopted by the invention and the beneficial effects of the invention are as follows:
a state evaluation method for a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler comprises the following steps of;
1) Explicitly evaluating the object and the basic information;
2) Defining detailed evaluation points;
3) The specific stage of the full-operation life cycle of the object is clearly evaluated;
4) Calculating a state factor C S ;
5) Calculating correction factor C C ;
6) Making a metal inspection scheme and implementing the scheme;
7) Obtaining a metal inspection result;
8) Evaluating point states;
9) Evaluating the state of an evaluation object;
10 Filing and feeding back the evaluation result.
The evaluation object of the step 1) is a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler, and the basic information comprises a design drawing, a design diameter, a design wall thickness, a design material and a latest overhaul record file;
the specific operation steps of the step 2) are as follows:
comprehensively considering maintenance plans, time, cost and past maintenance results, determining evaluation points in a targeted manner, and classifying the evaluation points into two types: the adapter tube and the socket are distinguished by subscripts nc and ts, respectively.
The specific operation steps of the step 3) are as follows:
determining which phase of the early, mid, end and end phases of the full operational life cycle the object is in;
all phases of the full operational life cycle | Time ranges for each phase of the full operational life cycle |
Early stage | (0,0.1L c ] |
Mid-stage | (0.1L c ,0.6L c ] |
End stage | (0.6L c ,0.85L c ] |
End stage | (0.85L c ,L c ] |
Wherein L is c For design life, it is generally defined as the design life of the unit for 30 years.
The specific operation steps for calculating the state factor in the step 4) are as follows:
based on the clear assessment object of step 3)A row life cycle stage for determining its corresponding state factor C S ;
All phases of the full operational life cycle | State factor C S |
Early stage | 1+s |
Mid-stage | 1 |
End stage | 1+2s |
End stage | 1+5s |
Wherein the value of s is looked up according to the following table based on the design and manufacturing data collected in step 1).
The specific operation steps for calculating the correction factor in the step 5) are as follows:
based on the feedback of the last evaluation result of the evaluation object, a correction factor C is determined according to the formula (1) C ;
In the formula, the values of the parameters delta and c are searched from the following table.
The specific operation steps of the step 6) are as follows:
comprehensively considering maintenance plan, time, cost and past maintenance results, and selecting proper projects from macro inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, wall thickness measurement, hardness inspection and oxide skin thickness measurement for the evaluation points determined in the step 2) to formulate a metal inspection scheme and implement.
The specific operation steps of the step 7) are as follows:
according to the metal inspection items determined in the step 6), obtaining all metal inspection results of the evaluation points, classifying the state parameters into three categories according to the metal inspection results, and confirming the state parameters CP and the weights Q corresponding to all the metal inspection items of all the evaluation points.
The specific operation steps of the step 8) are as follows:
performing state evaluation on the single evaluation point according to the metal inspection result obtained in the step 7), and defining the state of the single evaluation point as C k The evaluation model is shown as a formula (2);
evaluation pointState C of (2) k The numerical result of (2) normally falls within [0,4 ]]Within the interval range C k The state of the evaluation point becomes worse as the value of (2) changes from 0 to 4.
Weights Q of three types of state parameters in the formula (2) Ii 、Q IIi And Q IIIi Giving the rule of formula (3);
the specific operation steps in the step 9) are as follows:
counting all the evaluation points obtained in the step 8) according to classification of takeover and tube seat (subscript is nc and ts respectively), counting the number m of the takeover evaluation points and the number n of the tube seat evaluation points, and then carrying out overall evaluation on the evaluation object, wherein an evaluation model of a final state value is shown as a formula (12);
if the state C value of the evaluation object is 0, the state of the evaluation object is considered to be optimal, and when the C value is changed from 0 to 4, the state of the evaluation object gradually becomes worse; when the C value is larger than 2.5, the state of the evaluation object is general, but part of evaluation points are worse, so that the attention of technicians is required, and the maintenance or replacement treatment is timely carried out on part of evaluation points; when the C value is larger than 3.2, the state of the evaluation object is poor, and the state of most evaluation points is poor. If the individual evaluation point is in a poor state, the individual evaluation point can be replaced. If the overall condition of the assessment object is poor, particularly at the end and end stages of the full operational life cycle, the enterprise should be ready for the overall replacement of the assessment object.
The specific operation steps in the step 10) are as follows:
and 3) completely recording and archiving the state evaluation result of the evaluation object obtained in the step 9), and feeding back for the next evaluation to calculate the correction factor of the step 5).
The first step in the step 8)Class status parameters: macroscopic state parameter CP I1-k Results of macroscopic examination R I1-k : { no defect found, few suspected defects found, invention apparent defect } is defined as shown in formula (4):
the first type of state parameters in the step 8): surface state parameter CP I2-k From the result R of the surface inspection I2-k : { no defects found, surface defects found but eliminated after grinding, surface defects found but still present after grinding } are defined as shown in formula (5):
the second type of state parameter in the step 8): lossless state parameter CP II1-k From the result R of non-destructive inspection II1-k : { stage I, stage II, stage III, stage IV } is defined as shown in formula (6):
the second type of state parameter in the step 8): tissue state parameter CP II2-k From the result R of metallographic examination II2-k : { level 1, level 2, level 3, level 4, level 5 } is defined as shown in formula (7):
the third type of state parameter in the step 8): pipe diameter state parameter CP III1-k From the result R of pipe diameter inspection III1-k Definition, as shown in formula (8):
in the formula (8), D 0 The unit is mm for designing pipe diameter; e is the limit creep rate, the unit is that for the steam-water separator connecting pipe, the limit creep rate takes the values shown in the following table:
material of material | Alloy steel | Carbon steel |
e takes value | 2.5% | 3.5% |
The third type of state parameter in the step 8): wall thickness state parameter CP III2-k From the result R of the wall thickness inspection III2-k Defined as shown in formula (9):
in the formula (9), d 0 For designing the wall thickness, the unit is mm;
the third type of state parameter in the step 8): hardness state parameter CP III3-k From the result R of hardness test III3-k Defined as shown in formula (10):
the hardness in the formula (10) is Brinell hardness, HB L And HB H Respectively minimum and maximum extreme hardness forSteam-water separator connecting pipe and HB of common material L And HB H The values are summarized in the following table:
material of material | T22 | T23 | G102 | T91 | 12C1MoV | … |
HB L | 120 | 150 | 150 | 180 | 135 | … |
HB H | 163 | 220 | 220 | 250 | 179 | … |
The third type of state parameter in the step 8): scale state parameter CP III4-k Results R from examination of inner wall scale III4-k Defined as shown in formula (11):
in the formula (11), X H The maximum allowable inner wall scale thickness is given in mm. For steam-water separator connecting pipe, X of common material H The value summary is shown in the following table:
material of material | T22 | T23 | G102 | T91 | 12C1MoV | … |
X H | 0.30 | 0.30 | 0.45 | 0.30 | 0.35 | … |
The invention has the beneficial effects that:
the invention does not need to have abundant metal material basic knowledge, mechanical calculation knowledge, service life assessment knowledge and experience by an evaluator, does not need to bear extra test cost, is based on conventional metal test data such as macro test, surface flaw detection, nondestructive inspection, metallographic inspection, pipe diameter inspection, wall thickness measurement, hardness inspection and oxide skin thickness measurement aiming at the pipe seat and the connecting pipe of the steam-water separator of the supercritical or ultra-supercritical boiler, and carries out state evaluation on the pipe seat and the connecting pipe of the steam-water separator of the supercritical or ultra-supercritical boiler through correction of state factors and correction factors, thereby directly helping technicians of a thermal power plant to formulate a next maintenance strategy, and can be singly replaced if the state of the pipe seat and the connecting pipe of the steam-water separator of the supercritical or ultra-supercritical boiler is poor, and an enterprise is ready for evaluating the whole replacement of an object if the whole state is poor.
Taking the results of C repair of a steam-water separator tube seat at the left side of a 660MW supercritical boiler and taking over 12 months in 2020 as an example, the state evaluation is implemented according to the method of the invention, and the evaluation process and the final result are as follows.
Drawings
FIG. 1 is a schematic diagram of a state evaluation flow according to the present invention.
Detailed Description
The invention is further described below with reference to the drawings and examples.
As shown in fig. 1:
1) Explicitly evaluating object and basic information
The object to be evaluated is first explicitly the supercritical or ultra supercritical boiler steam separator nipple and socket.
In addition, it is also necessary to collect and explicitly evaluate the design drawings, design diameters, design wall thicknesses, design materials, and most recent overhaul record files of the object.
2) Clear detailed evaluation point
In order to know the actual state of the evaluation object in detail, it is generally recommended to check the evaluation object for a plurality of positions (pipe and socket), which are also called evaluation points, since the checking points ultimately take part in the state evaluation. And the evaluation points are divided into two categories: the adapter tube and the socket are distinguished by subscripts nc and ts, respectively.
3) Specific stage of full-operation life cycle of object under clear evaluation
The state of the evaluation object has a certain relation with the specific stage of the full-operation life cycle in which the evaluation object is positioned, and the state is not good due to design and manufacturing defects and installation hidden dangers in the early stage of the full-operation life cycle. Along with the stable operation of the unit, the unit enters the middle stage of the full-operation life cycle, and the evaluation object reaches the optimal state and can last for a long time. When the end stage of the full-operation life cycle is entered, the state of the evaluation object gradually deteriorates under the influence of the long-term peak shaving operation of the unit. When the material enters the final stage of the full-operation life cycle, the material is gradually aged under the high-temperature high-pressure service condition for a long time, and the rapid degradation of the state of the object is evaluated.
Determining which phase of the early, mid, end and end phases of the full operational life cycle the object is in;
all phases of the full operational life cycle | Time of full operation life cycle stagesInter-range |
Early stage | (0,0.1L c ] |
Mid-stage | (0.1L c ,0.6L c ] |
End stage | (0.6L c ,0.85L c ] |
End stage | (0.85L c ,L c ] |
Wherein L is c For design life, it is generally defined as the design life of the unit for 30 years.
4) Calculating a state factor C S
Determining the corresponding state factor C based on the stage of 3) definite evaluation object S ;
All phases of the full operational life cycle | State factor C S |
Early stage | 1+s |
Mid-stage | 1 |
End stage | 1+2s |
End stage | 1+5s |
Wherein the value of s is looked up according to the following table based on the design and manufacturing data collected in 1).
If all indexes in the design and manufacturing data are normal and no major problem is found, c takes a value of 0.01, otherwise, according to the problem found in the design and manufacturing stage, an evaluator can also adjust according to the actual situation of the component.
5) Calculating correction factor C C
Based on the feedback of the last evaluation result of the evaluation object, a correction factor C is determined according to the formula (1) C ;
In the formula, the values of the parameters delta and c are searched from the following table.
6) Making a metal inspection scheme and implementing
Comprehensively considering maintenance plan, time, cost and past maintenance results, and selecting proper projects from macro inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, wall thickness measurement, hardness inspection and oxide skin thickness measurement for the evaluation points determined in the step 2) to formulate a metal inspection scheme and implement.
7) Obtaining a metal inspection result
According to the metal inspection items determined in the step 6), obtaining all metal inspection results of the evaluation points, classifying the state parameters into three categories according to the metal inspection results, and confirming the state parameters CP and the weights Q corresponding to all the metal inspection items of all the evaluation points.
8) Evaluation point state evaluation
Performing state evaluation on the single evaluation point according to the metal inspection result obtained in the step 7), and defining the state of the single evaluation point as C k The evaluation model is shown in formula (2).
State C of evaluation point k The numerical result of (2) normally falls within [0,4 ]]Within the interval range C k The state of the evaluation point becomes worse as the value of (2) changes from 0 to 4.
Comprehensively considering the importance of various metal inspection projects, the implementation frequency, the accuracy of results and other factors, and the weights Q of three types of state parameters in the formula (2) Ii 、Q IIi And Q IIIi Giving the rule of formula (3);
the following gives an evaluation method of three types of state parameters of a single evaluation point.
8.1 State parameter evaluation of the first class
8.1.1 Macro state parameter evaluation corresponding to macro inspection
Results of macroscopic inspectionR I1-k Generally one of the sets { no defects found, out of specification defects found }, corresponding to the macroscopic state parameter CP I1-k The definition of (2) is shown in the formula (4).
8.1.2 Surface state parameter evaluation corresponding to surface flaw detection
Results of surface inspection R I2-k Generally { no defects found, surface defects found but removed after polishing, surface defects found but still present after polishing }, corresponding to the surface state parameter CP I2-k The definition of (2) is shown in the formula (5).
8.2 State parameter evaluation of the second class
8.2.1 Non-destructive state parameter assessment corresponding to non-destructive inspection
The nondestructive inspection project can be divided into ultrasonic wave, magnetic powder, penetration and ray detection, and the nondestructive inspection result R II1-k Generally defined as { class I, class II, class III, class IV }, if multiple nondestructive inspection items are implemented, selecting the nondestructive inspection item with the highest rating as the nondestructive inspection result, and corresponding nondestructive state parameter CP II1-k The definition of (2) is shown in a formula (6).
8.2.2 Lossless state parameter evaluation corresponding to metallographic examination
Results of metallographic examination R II2-k Is generally defined as { level 1, level 2, level 3, level 4, level 5 }, which corresponds to the organization state parameter CP II2-k The definition of (2) is shown in the formula (7).
8.3 Third class state parameter evaluation
8.3.1 Wall thickness state parameter evaluation corresponding to pipe diameter inspection
The external diameter creep of the evaluation object can gradually occur when the evaluation object operates under high temperature conditions, and the failure is easy to cause when the creep is serious.
Results of pipe diameter inspection R III1-k Corresponding pipe diameter state parameter CP III1-k The definition of (2) is shown in the formula (8).
In the formula (8), D 0 The unit is mm for designing pipe diameter; e is the limit creep rate, the unit is that for the steam-water separator connection, the limit creep rate takes on the values shown in the table below.
Material of material | Alloy steel | Carbon steel |
e takes value | 2.5% | 3.5% |
8.3.2 Wall thickness state parameter estimation corresponding to wall thickness inspection
The inner wall of the evaluation object can generate high-temperature oxidation under the erosion and corrosion action of high-temperature steam, and the base metal of the evaluation object is gradually consumed, so that the wall thickness is reduced, and the evaluation object has a worse state.
Results of wall thickness inspection R III2-k Corresponding wall thickness state parameter CP III2-k The definition of (2) is shown in the formula (9).
In the formula (9), d 0 For the design of the wall thickness, the unit is mm.
8.3.3 Hardness check corresponding hardness status parameter assessment
The evaluation object gradually ages under high temperature conditions, so that the hardness gradually decreases and the state becomes worse, and finally, failure may be caused.
Results of hardness inspection R III3-k Corresponding hardness state parameter CP III3-k The definition of (2) is shown in a formula (10).
The hardness in the formula (10) is Brinell hardness, HB L And HB H Respectively the minimum and maximum extreme hardness, and for the steam-water separator connecting pipe, HB of common materials L And HB H The values are summarized in the following table:
material of material | T22 | T23 | G102 | T91 | 12C1MoV | … |
HB L | 120 | 150 | 150 | 180 | 135 | … |
HB H | 163 | 220 | 220 | 250 | 179 | … |
8.3.4 Evaluation of scale state parameters corresponding to inner wall scale inspection
The inner wall of the evaluation object can generate high-temperature oxidation under the erosion and corrosion actions of high-temperature steam, and the formed inner wall oxide layer increases heat transfer resistance, so that the actual use temperature of the evaluation object is increased, and the aging of the material is aggravated.
Results of inner wall oxide skin inspection R III4-k Corresponding scale state parameter CP III4-k The definition of (2) is shown in the formula (11).
Formula (11), X H The maximum allowable inner wall scale thickness is given in mm. For steam-water separator connecting pipe, X of common material H The value summary is shown in the following table:
material of material | T22 | T23 | G102 | T91 | 12C1MoV | … |
X H | 0.30 | 0.30 | 0.45 | 0.30 | 0.35 | … |
9) Evaluation object state evaluation
And (3) counting all the evaluation points obtained in the step 8) according to classification of takeover and tube seat (subscripts are nc and ts respectively), counting the number m of the takeover evaluation points and the number n of the tube seat evaluation points, and then carrying out overall evaluation on the evaluation object, wherein an evaluation model of the final state value is shown as a formula (12).
If the state C value of the evaluation object is 0, the state of the evaluation object is considered to be optimal, and when the C value is changed from 0 to 4, the state of the evaluation object gradually becomes worse; when the C value is larger than 2.5, the state of the evaluation object is general, but part of evaluation points are worse, so that the attention of technicians is required, and the maintenance or replacement treatment is timely carried out on part of evaluation points; when the C value is larger than 3.2, the state of the evaluation object is poor, and the state of most evaluation points is poor. If the individual evaluation point is in a poor state, the individual evaluation point can be replaced. If the overall condition of the assessment object is poor, particularly at the end and end stages of the full operational life cycle, the enterprise should be ready for the overall replacement of the assessment object.
10 Filing and feeding back evaluation results
And 3) completely recording and archiving the state evaluation result of the evaluation object obtained in the step 9), and feeding back for the next evaluation to calculate the correction factor of the step 5).
The state of the supercritical or ultra-supercritical boiler steam-water separator tube seat and the connecting tube is obtained through the evaluation of the technical scheme, so that a thermal power plant technician can be helped to know the actual state of the supercritical or ultra-supercritical boiler steam-water separator tube seat and the connecting tube, the change trend of the state of the supercritical or ultra-supercritical boiler steam-water separator tube seat and the connecting tube can be predicted according to the multiple state evaluation results of the same evaluation point, the state results of all the evaluation points can be synthesized to evaluate the integral state of the supercritical or ultra-supercritical boiler steam-water separator tube seat and the connecting tube, and the method has important significance in making a maintenance plan and a replacement strategy.
Claims (8)
1. A state evaluation method of a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler is characterized by comprising the following steps of;
1) Explicitly evaluating the object and the basic information;
2) Defining detailed evaluation points;
3) The specific stage of the full-operation life cycle of the object is clearly evaluated;
4) Calculating a state factor C S ;
5) Calculating correction factor C C ;
6) Making a metal inspection scheme and implementing the scheme;
7) Obtaining a metal inspection result;
8) Evaluating point states;
9) Evaluating the state of an evaluation object;
10 Filing and feeding back an evaluation result;
the specific operation steps of the step 5) are as follows:
based on the feedback of the last evaluation result of the evaluation object, a correction factor C is determined according to the formula (1) C ;
Wherein, the values of the parameters delta and c are searched from the following table;
the specific operation steps of the step 8) are as follows:
performing state evaluation on the single evaluation point according to the metal inspection result obtained in the step 7), and defining the state of the single evaluation point as C k The evaluation model is shown as a formula (2);
state C of evaluation point k The numerical result of (2) normally falls within [0,4 ]]Within the interval range, when C k As the value of (2) changes from 0 to 4, the state of the evaluation point becomes worse;
weights Q of three types of state parameters in the formula (2) Ii 、Q IIi And Q IIIi Giving the rule of formula (3);
the first type of state parameters in the step 8): macroscopic viewStatus parameter CP I1-k Results of macroscopic examination R I1-k : { no defect found, suspicious defect found, defect found } is defined as shown in formula (4):
the first type of state parameters in the step 8): surface state parameter CP I2-k From the result R of the surface inspection I2-k : { no defects found, surface defects found but eliminated after grinding, surface defects found but still present after grinding } are defined as shown in formula (5):
the second type of state parameter in the step 8): lossless state parameter CP II1-k From the result R of non-destructive inspection II1-k : { stage I, stage II, stage III, stage IV } is defined as shown in formula (6):
the second type of state parameter in the step 8): tissue state parameter CP II2-k From the result R of metallographic examination II2-k : { level 1, level 2, level 3, level 4, level 5 } is defined as shown in formula (7):
the third type of state parameter in the step 8): pipe diameter state parameter CP III1-k From the result R of pipe diameter inspection III1-k Definition, as shown in formula (8):
in the formula (8), D 0 The unit is mm for designing pipe diameter; e is the limit creep rate, and the unit is;
the third type of state parameter in the step 8): wall thickness state parameter CP III2-k From the result R of the wall thickness inspection III2-k Defined as shown in formula (9):
in the formula (9), d 0 For designing the wall thickness, the unit is mm;
the third type of state parameter in the step 8): hardness state parameter CP III3-k From the result R of hardness test III3-k Defined as shown in formula (10):
in the formula (10), HB L And HB H Respectively a minimum limit hardness value and a maximum limit hardness value;
the third type of state parameter in the step 8): scale state parameter CP III4-k Results R from examination of inner wall scale III4-k Defined as shown in formula (11):
formula (11), X H The maximum allowable inner wall scale thickness is given in mm.
2. The method for evaluating the state of the steam-water separator tube seat and the connecting tube of the supercritical or ultra-supercritical boiler according to claim 1, wherein the evaluation object in the step 1) is the steam-water separator tube seat and the connecting tube of the supercritical or ultra-supercritical boiler, and the basic information comprises a design drawing, a design diameter, a design wall thickness, a design material and a latest overhaul record file.
3. The method for evaluating the state of a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler according to claim 1, wherein the specific operation steps of the step 2) are as follows:
all evaluation points of the evaluation object are explicitly evaluated and are divided into: the take-over evaluation point and the tube seat evaluation point are respectively distinguished by subscripts nc and ts.
4. The method for evaluating the state of a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler according to claim 1, wherein the step 3) comprises the following specific operation steps:
determining which phase of the early, mid, end and end phases of the full operational life cycle the object is in;
Wherein L is c For the design life, it is defined as the design life of the unit for 30 years.
5. The method for evaluating the state of a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler according to claim 1, wherein the specific operation steps in the step 4) are as follows:
determining the corresponding state factor C based on the stage of the clear evaluation object in the step 3) S ;
Wherein the design and manufacturing data collected according to step 1);
6. the method for evaluating the state of a steam-water separator tube seat and a connecting tube of a supercritical or ultra-supercritical boiler according to claim 1, wherein the step 6) comprises the following specific operation steps:
comprehensively considering maintenance plan, time, cost and past maintenance results, selecting items from macro inspection, surface flaw detection, nondestructive flaw detection, metallographic inspection, pipe diameter inspection, wall thickness measurement, hardness inspection and oxide skin thickness measurement to formulate a metal inspection scheme and implementing aiming at the evaluation points determined in the step 2).
7. The method for evaluating the state of a steam separator tube seat and a connecting tube of a supercritical or ultra supercritical boiler according to claim 1, wherein the specific operation steps of the step 7) are as follows:
according to the metal inspection items determined in the step 6), obtaining all metal inspection results of the evaluation points, classifying the state parameters into three categories according to the metal inspection results, and confirming the state parameters CP and the weights Q corresponding to all the metal inspection items of all the evaluation points;
8. the method for evaluating the state of a steam separator tube seat and a connecting tube of a supercritical or ultra supercritical boiler according to claim 1, wherein the specific operation steps in the step 9) are as follows:
counting all the evaluation points obtained in the step 8) according to classification of the takeover and the tube seat, counting the number m of the evaluation points of the takeover and the number n of the evaluation points of the tube seat, and then carrying out overall evaluation on the evaluation object, wherein an evaluation model of a final state value is shown as a formula (12);
if the state C value of the evaluation object is 0, the state of the evaluation object is considered to be optimal, and when the C value is changed from 0 to 4, the state of the evaluation object gradually becomes worse; when the C value is more than 2.5, the attention of technicians is required, and part of evaluation points are timely maintained or replaced; when the C value is more than 3.2, the enterprise is ready for evaluating the whole replacement of the object;
the specific operation steps in the step 10) are as follows:
and 3) completely recording and archiving the state evaluation result of the evaluation object obtained in the step 9), and feeding back for the next evaluation to calculate the correction factor of the step 5).
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