TWI711996B - Maintenance management menu decision method and factory maintenance management method - Google Patents

Abstract

The maintenance management menu determination method of at least one embodiment of the present invention is a maintenance management menu determination method of a factory, and is characterized by: having: predict the maintenance target site based on the inspection result of the maintenance target site in contact with the fluid in the factory If the predicted remaining life is shorter than the allowable period, the input factor value used in the remaining life evaluation of the maintenance target part will be changed by the measures to extend the life of the maintenance target part The step of re-predicting the aforementioned remaining life; and if it is confirmed that the re-predicted remaining life is longer than the aforementioned allowable period, a step of formulating a maintenance management menu for the aforementioned factory that includes the aforementioned life extension measures.

Description

Maintenance management menu decision method and factory maintenance management method

This disclosure is about the maintenance management menu decision method and the factory maintenance management method.

For example, in the piping of a boiler that is used for a long time in a high-temperature and high-pressure environment, creep damage may occur in the welded parts of the piping. As the creep damage progresses, it is necessary to evaluate the remaining life according to the progress of the creep damage, and timely repair the welded part. Therefore, the degree of creep damage in the welded portion is measured to evaluate the remaining life (see Patent Document 1). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5086615

(The problem to be solved by the invention)

In the method for evaluating the remaining life disclosed in Patent Document 1, if it is determined that the estimated remaining life is less than a predetermined time, that is, for example, the time equivalent to the period until the next inspection, until the next inspection, There is a high possibility that the inspection object will be broken, and some treatment is desired. However, for example, when the inspection target is replaced, if the replacement cannot be obtained immediately, after the factory is temporarily started, the factory must be stopped again in order to replace the inspection target before the next inspection. Therefore, there are costs related to the suspension of the factory after the temporary operation and the re-operation after the inspection object is replaced, or the loss of the benefits related to the suspension of the factory after the temporary operation. As shown above, there are cases where it is desired to extend the remaining life of the inspection object by a predetermined period (for example, an allowable period).

In view of the above-mentioned circumstances, the purpose of at least one embodiment of the present invention is to extend the life of the maintenance target part of the factory by a predetermined period. (Means to solve the problem)

(1) The maintenance management menu decision method of at least one embodiment of the present invention is the maintenance management menu decision method of the factory, and is characterized by: have: Steps of predicting the remaining life of the maintenance target part based on the inspection result of the inspection result of the maintenance target part in contact with the fluid in the aforementioned factory; If the predicted remaining life is shorter than the allowable period, the aforementioned remaining life when the input factor value used for the remaining life evaluation of the maintenance target part is changed by the aforementioned measures to extend the life of the maintenance target part will be repeated. The forecasting steps; and If it is confirmed that the predicted remaining life is longer than the allowable period, a procedure for the maintenance management menu for the factory including the life extension measures is drawn up.

Using the method in (1) above, after confirming that the remaining life after adopting life extension measures is longer than the allowable period, draw up a maintenance management menu that includes the life extension measures, so that the remaining life of the maintenance target can be made longer than the allowable period For longer.

(2) In some embodiments, in the method of (1) above, the life extension measures include: operating conditions mitigation measures to reduce the load on the maintenance target part by changing the operating conditions of the factory, or At least one of the local countermeasures implemented in the maintenance target part.

According to the method (2) above, by taking measures to ease the operating conditions, it is possible to reduce the load on the multiple sites within the range affected by the change in the operating conditions of the factory. In addition, by implementing local countermeasures to the parts to be maintained, the scope of the impact caused by the countermeasures can be limited.

(3) In some embodiments, in the method of (2) above, the step of re-predicting the remaining life includes: obtaining the input factor value changed by the aforementioned operating condition mitigation countermeasure or the aforementioned partial countermeasure, According to the calculated input factor value, the step of predicting the aforementioned remaining life.

According to the method (3) above, the input factor value changed by the operation condition mitigation countermeasure or the local countermeasure is obtained, so the obtained input factor value becomes the appropriate one. According to the obtained input factor value The accuracy of the remaining life predicted will be improved.

(4) In some embodiments, in the method (2) or (3) above, the aforementioned life extension countermeasure is a countermeasure that combines the aforementioned operating condition relaxation countermeasure and the aforementioned partial countermeasure.

With the above method (4), by combining the operating condition mitigation measures and local measures, the amount of changes in the operating conditions of the factory can be suppressed, the impact on the operation of the plant can be suppressed, and the local measures can be simplified.

(5) In some embodiments, in the method of (4) above, the aforementioned life extension countermeasures are based on the loss of benefits and increased costs compared with the case of separately implementing the aforementioned operating condition mitigation countermeasures and the aforementioned partial countermeasures. A combination of the aforementioned operating condition mitigation measures selected by the method of reducing the sum and the aforementioned partial measures.

For example, in the operating condition mitigation measures, due to the change of the operating conditions of the factory, the operating efficiency of the factory is reduced, and there is a case in which a lost profit occurs. Generally speaking, there is a tendency that the wider the operating conditions of the factory are changed, the more the operating efficiency of the factory decreases and the loss of benefits increases. In addition, in local countermeasures, generally speaking, the more effective the countermeasure is, the more the cost of countermeasures tends to increase. Therefore, for example, by combining operating condition mitigation measures and local measures, although the loss of profits due to changes in the operating conditions of the factory may be generated, the cost increase due to the implementation of local measures can be suppressed. In other words, by combining operating condition mitigation measures and local measures, although the cost of implementing local measures will be incurred, the lost profits due to changes in the operating conditions of the plant can be reduced. Therefore, by the method of (5) above, an appropriate combination of operating condition mitigation measures and partial measures can be selected, thereby suppressing the sum of lost benefits and increasing costs.

(6) In some embodiments, in any of the methods (2) to (5), the aforementioned operating condition mitigation measures include: measures to reduce the temperature of the fluid in contact with the maintenance target part, or the fluid At least one of the measures to reduce the pressure.

By the above method (6), the load applied to the part to be maintained can be reduced, so the remaining life of the part to be maintained can be prolonged.

(7) In some embodiments, in any of the methods (2) to (6), the aforementioned local countermeasures include: local cooling for local cooling of the maintenance target part, and relaxation of the stress in the maintenance target part At least one of stress relief measures or damage recovery measures for recovering the damage in the aforementioned maintenance target part.

According to the above method (7), the remaining life of the part to be maintained can be extended by at least one of local cooling, stress relief measures, and damage recovery measures.

(8) In some embodiments, in any one of the methods (2) to (7), the aforementioned local countermeasures include: reinforcement of the aforementioned maintenance target part, or at least the modification of the restriction conditions in the aforementioned maintenance target part One is as a stress relaxation measure to alleviate the stress in the aforementioned maintenance target part.

According to the above method (8), at least one of the reinforcement of the maintenance target part or the modification of the restriction conditions in the maintenance target part can relax the stress in the maintenance target part and extend the remaining life of the maintenance target part.

(9) In some embodiments, in any of the above methods (2) to (8), the aforementioned local countermeasure system includes at least: repair welding of the aforementioned maintenance target part as a method for restoring the damage in the aforementioned maintenance target part Damage recovery measures.

According to the above method (9), damage recovery measures including at least repair welding of the maintenance target part are used to restore the damage in the maintenance target part, thereby extending the remaining life of the maintenance target part.

(10) In some embodiments, in any of the methods (1) to (9) above, in the step of drawing up the maintenance management menu, if there is a plural number, the remaining life can be extended by the allowable period. As a countermeasure, the effect of applying at least one of the aforementioned life extension countermeasures is converted into an amount, and the result of the amount conversion is considered to determine the maintenance management menu.

According to the method (10) above, it is possible to make the remaining life of the maintenance target portion longer than the allowable period while suppressing the economic loss due to the implementation of life extension measures.

(11) In some embodiments, in any one of the methods (1) to (10) above, in the step of re-estimating the remaining life, the review of the allowable period or the review of the input factor value is performed After at least one of the above, predict the aforementioned remaining life.

According to the method of (11) above, after at least one of the review of the allowable period or the review of the input factor value is performed, the remaining life is predicted. For example, if the graph can be shortened to find the extended period due to life extension measures, It is possible to suppress the wide range of changes in the operating conditions of the factory due to the measures to ease the operating conditions, or to simplify the local measures implemented on the maintenance target parts.

(12) In some embodiments, in any of the methods (1) to (11) above, the aforementioned factory is a power plant, The aforementioned stream system vapor.

Using the method in (12) above, as described in (1) above, after confirming that the remaining life after adopting the life extension measure is longer than the allowable period, draw up a maintenance management menu that includes the life extension measure, thereby enabling power generation The remaining life of the maintenance target parts in the factory that are in contact with steam is longer than the allowable period.

(13) At least one embodiment of the plant maintenance management method of the present invention is characterized by: have: Determine the steps of the aforementioned factory's maintenance management menu by using any of the above-mentioned maintenance management menu selection methods (1) to (12); According to the aforementioned maintenance management menu, perform the aforementioned maintenance management steps of the maintenance target part; and After the aforementioned maintenance management, the step of monitoring the aforementioned maintenance target part is performed.

According to the above method (13), by implementing life extension measures, the remaining life of the maintenance target part can be made longer than the allowable period, and the state of the maintenance target part after the plant operation can be grasped.

(14) In some embodiments, in the method of (13) above, in the step of monitoring the maintenance target part, items that affect the value of the input factor used when re-estimating the remaining life are monitored, and It is determined whether or not it is out of the allowable range of the aforementioned items that should be satisfied in order for the predicted remaining life to be longer than the aforementioned allowable period.

By the method of (14) above, it can be judged whether the remaining life of the maintenance target part can be shorter than the allowable period. Therefore, if necessary, additional life extension measures can be implemented to make it longer than the allowable period. Further correspondence.

(15) In some embodiments, the method of (14) above additionally includes: When it is determined in the step of monitoring the maintenance target part that the value of the aforementioned item is out of the aforementioned allowable range, the step of predicting the new remaining life when the input factor value is changed by the new life extension countermeasure of the maintenance target part; and If it is confirmed that the aforementioned new remaining life is longer than the allowable period, a procedure for the maintenance management menu for the aforementioned factory including the aforementioned new life extension measures is drawn up. After confirming that the new remaining life after adopting the new life extension measures is longer than the allowable period by the method of (15) above, a maintenance management menu including the new life extension measures is drawn up, so that the remaining life of the maintenance target parts can be made It is longer than the allowable period. (Effect of Invention)

According to at least one embodiment of the present invention, the life of the maintenance target part of the factory can be extended by a predetermined period.

Several embodiments of the present invention will be described below with reference to the attached drawings. Among them, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiment or shown in the drawings are merely illustrative examples, and are not intended to limit the scope of the present invention thereto. For example, "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" and other expressions that express relative or absolute arrangement are formed to not only express strictly The configuration shown above also means a state of relative displacement with tolerance, or an angle or distance that can achieve the same function. For example, the expression representing the state where things such as "same", "equal", and "homogeneous" are equal is formed to not only rigorously express the state of equality, but also express the state of tolerance or difference in degree of obtaining the same function. For example, the expression system representing shapes such as a quadrangular shape or a cylindrical shape is formed to not only represent a quadrangular shape or a cylindrical shape in a geometrically rigorous sense, but also indicate that the same effect is included, including irregularities or inverted portions. Shapes such as corners. On the other hand, the expressions of "presence", "have", "have", "include", or "have" are not exclusive expressions that exclude the existence of other elements.

First, referring to Fig. 1, an overview of the maintenance management menu decision method and the factory maintenance management method of several embodiments will be explained. Fig. 1 is a diagram showing each process in the maintenance management method of a factory using the maintenance management menu determination method of several embodiments. The maintenance management method of the factory of several embodiments includes: step S1 of selecting a maintenance target part, step S1 of performing inspection of the maintenance target part, step S3 of determining a maintenance management menu, step S7 of performing maintenance management of the maintenance target part, and Step S8 of monitoring the maintenance target part is performed. The maintenance management menu decision method of some embodiments includes the step S3 of deciding the maintenance management menu. The maintenance management menu decision method and factory maintenance management method of some implementation forms are suitable for the maintenance management of metal components that are used for a long time under high temperature and heavy load environment. The maintenance management menu decision method and the maintenance management of the factory The method is, for example, suitable for maintenance and management of welded parts such as steam pipes that connect boilers and steam turbines in thermal power plants. Welding parts in steam pipes and the like include heat-affected parts due to welding. Creep damage as shown below occurs in the heat-affected zone. In other words, creep holes occur in the heat-affected zone due to long-term use at high temperatures. The number of creeping holes increases due to long-term use, and adjacent creeping holes are connected to each other to cause cracks. Then, the crack gradually grows, and finally penetrates the welded part in the thickness direction, and internal fluid leakage occurs. Therefore, in the operation of boilers and the like, it is necessary to properly maintain the welded parts such as steam piping.

The following describes the outline of each process in the maintenance management method of the factory in some embodiments. Among them, the various projects in the maintenance management method of the factory in several embodiments do not have to be carried out in the order shown in Figure 1, and there may be unimplemented projects as described later, or in the order shown in Figure 1. Projects implemented in different sequences may also be implemented repeatedly.

(Step S1 for selecting parts to be maintained) The step S1 of selecting a maintenance target part is a step of selecting a maintenance target part for performing maintenance management among welding parts such as a plurality of steam pipes in the factory.

(Step S2 for inspection of maintenance target parts) Step S2 of performing inspection of the maintenance target part is a step of performing flaw detection and inspection on the maintenance target part selected in step S1 of selecting the maintenance target part. For the flaw detection inspection performed in step S2 of inspecting the maintenance target part, for example, the phased array method, the UT method, the aperture synthesis method, the high frequency UT method, or the ultrasonic noise method can be used. Among them, the high-frequency UT method here refers to flaw detection using ultrasonic waves with frequencies above 20 MHz. Step S2 of inspecting the maintenance target part is implemented when the factory is stopped, such as a periodic inspection of the factory. In the following description, step S2 of inspecting the maintenance target part is performed at the time of the periodic inspection of the factory, and the periodic inspection at the time of implementation of step S2 of inspecting the maintenance target part is referred to as this periodic inspection. Among them, the next scheduled regular inspection after this regular inspection is called the next regular inspection, and the next regular inspection is called the next regular inspection.

(Step S3 to determine the maintenance management menu) The step S3 of determining the maintenance management menu includes the step S4 of predicting the remaining life of the maintenance target part described below, the step S5 of re-estimating the remaining life, and the step S6 of drawing up the maintenance management menu.

(Step S4 for predicting the remaining life of the maintenance target part) The step S4 of predicting the remaining life of the maintenance target part is a step of predicting the remaining life of the maintenance target part based on the inspection result of the maintenance target part performed in step S2 of the inspection of the maintenance target part. The remaining life refers to the time from the current point to the point where the maintenance target part is broken due to creep damage. In the prediction system of the remaining life, for example, crack progress calculation, FEM, damage mechanics evaluation, hole simulation method, or tissue simulation method can be used.

(Step S5 to predict the remaining life) The step S5 of re-predicting the remaining life is a step performed when the remaining life predicted in the step S4 of predicting the remaining life of the maintenance target part is shorter than the allowable period or when the relative allowable period is less. Here, the allowable period refers to, for example, the period until the next periodic inspection afterwards, and is the period until the period when the remaining life expectancy of the maintenance target part is expected to exceed. In step S5 of re-predicting the remaining life, the input factor value used for the remaining life evaluation (prediction of the remaining life) of the maintenance target part is reviewed to predict the remaining life again. In addition, in step S5 of re-estimating the remaining life, there are cases where the allowable period is reviewed.

In the review of the input factor value, it is considered to review the input factor value by reviewing the margin of the input factor value to the safety side.

Take the case of reviewing the input factor value by reviewing the margin of the input factor value to the safety side. For example, the input factor used when initially predicting the remaining life span is the relevant maintenance target part In the design value of the machine, the measured value is considered as the input factor value after the review. That is, generally speaking, there is a margin in the design value, and it is often set to a value more severe than the actual value. For example, the design value of the stress or temperature applied to the maintenance target part is often considered to be larger than the actual stress or temperature applied to the maintenance target part. Therefore, by using the actual measured value as the input factor value after the review, it is expected that the remaining life expectancy will be longer than the allowable period. Among them, the estimated value can also be used instead of the actual measured value as the input factor value after the review. For example, if it is difficult to measure the actual measurement value, the estimated value in the maintenance target part can be calculated from the operating conditions of the factory or the actual measurement value in the vicinity of the maintenance target part. For example, if the maintenance target part is a welded part in a steam pipe, the temperature or pressure of the steam flowing to the steam pipe can be obtained from the operation data of the factory to estimate the temperature or stress value in the maintenance target part.

In addition, in the review of the input factor value, it is considered to change the input factor value by the measures to extend the life of the maintenance target part described later. That is, it is assumed that a countermeasure for changing the value of the input factor to extend the remaining life (life extension countermeasure) is implemented to change the value of the input factor. Among them, in step S6 of drafting the maintenance management menu described later, it is also possible to implement step S5 of re-estimating the remaining life during the process of reviewing the measures for extending the life of the part to be maintained. Enter the factor value to predict the remaining life.

Take the example of the review allowable period, such as the allowable period before the review, for example, during the periodical inspection carried out every 2 years, the period until the next periodical inspection, that is, 4 years, consider Set the allowable period after the review to the period until the next periodic inspection, that is, 2 years. In addition, depending on the situation, such as a temporary factory shutdown, the period until a period different from the period of regular inspection may be the allowable period after the review. In addition, in step S5 of re-estimating the remaining life, either one of the review of the input factor value and the review of the allowable period may be performed, or both may be performed.

That is, in some embodiments, in step S5 of re-predicting the remaining life, at least one of the review of the allowable period or the review of the input factor value is performed, and then the remaining life is predicted. After at least one of the review of the allowable period or the review of the input factor value is performed, the remaining life can be predicted. If the period extended due to life extension measures, for example, can be shortened, measures can be taken for mitigating operating conditions. Suppression of the wide range of changes in plant operating conditions, or simplification of local countermeasures for maintenance target parts.

(Step S6 of drafting maintenance management menu) Step S6 of formulating a maintenance management menu is a step of formulating a maintenance management menu for the factory including life extension measures. For example, in step S6 of drawing up a maintenance management menu, if the re-predicted remaining life in step S5 of re-estimating the remaining life is shorter than the allowable period, a life extension countermeasure is drawn up. Specifically, the following measures are proposed for life extension.

Fig. 2 is a graph in which the temperature of the maintenance target part is taken on the horizontal axis and the stress of the maintenance target part is taken on the vertical axis. In the graph of FIG. 2, the solid line plot P0 represents the plot of temperature and stress acting on the maintenance target part during plant start-up, and the former is checked in step S5 of the remaining life prediction again. In the graph of FIG. 2, the dotted plot P1 represents the plot of the temperature and stress acting on the maintenance target part during the start of the factory, and the input factor value is checked in step S5 of the remaining life prediction again. In the graph of FIG. 2, the solid line system represents an iso-life line L0 under the temperature and stress conditions at which the remaining life of the maintenance target portion is equal to the allowable period. The iso-life line L0 is the iso-life line before the input factor value or the allowable period is checked in step S5 of re-estimating the remaining life. In the graph of FIG. 2, the broken line L1 is an isolife line L1 indicating the temperature and stress conditions at which the remaining life of the maintenance target portion is equal to the allowable period. The iso-life line L1 is the iso-life line after checking the input factor value or the allowable period in step S5 of re-estimating the remaining life. The dashed line L2 in the graph of FIG. 2 will be described later.

If the plant is restarted after this periodic inspection, if the temperature and stress acting on the maintenance target area are equivalent to the temperature and stress in the left area of the isolife line L0, the remaining life of the maintenance target area is greater than the allowable before the inspection The period is longer, and if it is the temperature and stress in the right area corresponding to the isolife line L0, the remaining life of the maintenance target part is shorter than the allowable period before the review. Similarly, if the plant is restarted after this periodic inspection, and if the temperature and stress acting on the maintenance target part are equivalent to the temperature and stress in the left region of the isolife line L1, the remaining life of the maintenance target part will be compared to the review The subsequent allowable period is longer, and if it is the temperature and stress in the right region corresponding to the equal life line L1, the remaining life of the maintenance target part is shorter than the allowable period after the review.

If the re-predicted remaining life in step S5 of re-estimating the remaining life is shorter than the allowable period, as shown in FIG. 2, the dotted plot P1 is a region located on the right side of the iso-life line L1. Therefore, after this periodic inspection, when the plant is restarted, at least one of the temperature and stress of the maintenance target site is changed so that the temperature and stress conditions of the maintenance target site are at least in the area to the left of the isometric line L1 Therefore, the remaining life of the maintenance target part can be longer than the allowable period.

As a countermeasure (life extension countermeasure) for changing the value of the input factor so as to extend the remaining life, that is, at least one of the temperature or stress of the maintenance target part, the following countermeasures can be cited.

(1) Measures to ease operating conditions The operating condition mitigation measures are life extension measures that reduce the load on the parts to be maintained by changing the plant operating conditions. For example, if the part to be maintained is a welded part in a steam pipe, the temperature of the part to be maintained can be lowered by lowering the temperature of the steam flowing to the steam pipe, as indicated by the dotted line P2. In addition, for example, if the maintenance target part is a welded part in a steam pipe, the stress of the maintenance target part can be reduced by reducing the pressure of the steam flowing to the steam pipe, as indicated by the dotted line P3. In addition, for example, if the part to be maintained is a welded part in a steam pipe, the temperature and pressure of the steam flowing to the steam pipe can be lowered, as shown by the dotted line P4, to reduce the temperature and stress of the part to be maintained.

In the operating condition mitigation measures, as described above, since the operating conditions of the factory are changed, it is possible to reduce the load on the maintenance target parts of the multiple locations within the range affected by the change of the operating conditions of the factory, and to extend the remaining life. In addition, the measures for mitigating the operating conditions include at least one of measures to reduce the temperature of the fluid in contact with the site to be maintained or measures to reduce the pressure of the fluid. Therefore, it is possible to reduce the load on the site to be maintained and extend the temperature of the site to be maintained. Remaining life. Among them, in the operating condition mitigation measures, as described above, since the operating conditions of the factory are changed, it is necessary to consider the impact on the operation of the factory. For example, it is necessary to consider a situation in which the operating efficiency of the factory may decrease due to the reduction of the temperature or pressure of the steam.

(2) Local countermeasures implemented on maintenance target parts The partial measures implemented on the maintenance target parts are the life extension measures implemented locally on the maintenance target parts. In the following description, the local countermeasures implemented on the maintenance target part are also referred to as partial countermeasures only. The local countermeasures include, for example, stress relaxation countermeasures to alleviate the stress in the maintenance target part, local cooling to locally cool the maintenance target part, and damage recovery countermeasures to restore the damage in the maintenance target part.

(2-1) Stress relaxation measures The stress mitigation measures are measures to alleviate the stress of the maintenance target part by implementing at least one of reinforcement of the maintenance target part or modification of the restriction conditions in the maintenance target part.

The reinforcement of the maintenance target part is a countermeasure for winding a heat-resistant and linear expansion coefficient of a cable made of the same material as the piping in a state where a pressing force is applied to the piping, for example, in the maintenance target part and the surrounding area in the pipe. By implementing reinforcement of the maintenance target part, as shown by the dotted line plot P3, the stress acting on the maintenance target part can be reduced. In addition, by performing surfacing welding on the maintenance target part, the wall thickness in the maintenance target part can be increased to strengthen the maintenance target part.

The modification of the restriction conditions in the maintenance target part is a countermeasure to reduce the stress that acts on the maintenance target part during the start of the factory. For example, a support structure including the pipe of the maintenance target part provides a restraining force to the pipe. For example, if the maintenance target portion is a circumferential weld that connects pipes to each other, a pressing force in the pipe axis direction is applied to the pipe so that the circumferential weld is compressed in the pipe axis direction of the pipe. By changing the restriction conditions in the maintenance target part, for example, as shown by the broken line plot P3, the stress acting on the maintenance target part can be reduced.

As shown above, in some embodiments, at least one of the reinforcement of the maintenance target part or the modification of the restriction condition in the maintenance target part is used as a stress relief measure. Therefore, the reinforcement of the maintenance target part, or the maintenance target part At least one of the changes in the restriction conditions of, can relax the stress in the maintenance target part and prolong the remaining life of the maintenance target part.

(2-2) Local cooling Local cooling is a measure to reduce the temperature of the maintenance target part by locally cooling the maintenance target part. For example, if the part to be maintained is a welded part in a steam pipe, the temperature of the part to be maintained can be lowered by blowing steam or air at a temperature lower than the temperature of the steam flowing to the steam pipe around the part to be maintained. . Thereby, as shown by the dotted line plot P5, for example, the temperature acting on the part to be maintained can be reduced. Among them, if the local cooling is performed, the temperature around the maintenance target site decreases and the periphery of the maintenance target site shrinks. Therefore, the stress system acting on the maintenance target site may be greater than before the local cooling. Therefore, it is necessary to add the change in the stress acting on the maintenance target part to set the amount of temperature drop in the maintenance target part.

(2-3) Damage recovery measures The damage recovery countermeasure is a countermeasure to repair the damage in the maintenance target part by performing repair welding on the maintenance target part, for example. Among them, in terms of damage recovery measures, for example, the maintenance target part can be heated while the thermal expansion of the maintenance target part is restricted, so that the creep holes or cracks of the maintenance target part can be crimped/repaired by thermal stress. . As shown above, by implementing damage recovery measures, for example, as shown by the line L2 of the broken line, the position of the line of equal life is moved.

As described above, in some embodiments, local countermeasures include at least repair welding of the maintenance target part as a damage recovery countermeasure for recovering the damage in the maintenance target part. Therefore, damage recovery measures including at least repair welding of the maintenance target part can restore the damage in the maintenance target part, thereby prolonging the remaining life of the maintenance target part.

As described above, in some embodiments, the local countermeasure system includes: local cooling to locally cool the part to be maintained, stress relaxation countermeasures to relieve stress in the target part of maintenance, or damage recovery countermeasures to restore damage in the target part of maintenance At least one of them. In this way, the remaining life of the part to be maintained can be extended by at least one of local cooling, stress relief measures, and damage recovery measures.

(About the calculation of the input factor value) Since the input factor value is changed by the aforementioned various operating condition mitigation measures or partial measures, the input factor value after the change is obtained as shown below, for example. For example, if the temperature of the steam flowing to the steam pipe is changed as the operating condition of the factory, and if the pipe has a large steam flow rate and is insulated, the temperature of the maintenance target part in the pipe can be regarded as equal to the steam temperature. Among them, consider, for example, piping where there is a maintenance target part, such as a branch pipe, where the steam flow rate is lower than that of the main piping through which steam flows, or in a piping that is not insulated, the temperature of the maintenance target part is not considered When the temperature is equal to that of the steam flowing through the main pipe. In the case shown above, if the temperature of the maintenance target part cannot be directly measured, some method must be used to estimate the temperature of the maintenance target part. For example, if the temperature of the branch pipe or the temperature of the steam circulating in the branch pipe can be obtained on the downstream side of the maintenance target part in the branch pipe, the temperature obtained and the temperature of the steam circulating in the main pipe can also be borrowed The temperature of the part to be maintained is estimated by interpolation. Among them, when estimating the temperature of the maintenance target part, it is appropriate to consider the heat generation or endotherm in the pipes surrounding the maintenance target part.

In addition, if the pressure of the steam flowing to the steam pipe is changed as the operating condition of the factory, the above-mentioned pressure value as the operating condition can also be referred to by adding the shape of the pipe including the maintenance target part, the pressure loss of the steam, and the The state of support is used to estimate the stress in the part to be maintained.

For example, if a local countermeasure is implemented, the local countermeasure can be used to estimate the degree of temperature reduction or stress reduction that is estimated, thereby estimating the temperature or stress in the part to be maintained.

As shown above, the input factor value is changed by the above-mentioned various operating condition mitigation measures or partial measures. Therefore, in step S6 of preparing the maintenance management menu, the process of preparing the maintenance management menu returns to step S5 of predicting the remaining life. Based on the changed input factor value obtained as described above, the remaining life is predicted. That is, the step S5 of re-estimating the remaining life includes the step of obtaining the input factor value changed by the operating condition mitigation countermeasure or the local countermeasure, and predicting the remaining life again based on the obtained input factor value. As shown above, since the input factor value changed by the operating condition mitigation countermeasure or the partial countermeasure is obtained, the obtained input factor value becomes the appropriate one, and the obtained input factor value is re-predicted The accuracy of the remaining life is improved.

In some embodiments, as described above, iteratively enumerate candidates for life extension measures in step S6 of drafting the maintenance management menu, and then predict the remaining life when candidates for life extension measures are implemented in step S5 of restoring the remaining life. And judge whether the predicted remaining life is longer than the allowable period. Next, in step S6 of drawing up the maintenance management menu, it is confirmed that the life extension countermeasure that the re-predicted remaining life is longer than the allowable period is drawn as the life extension countermeasure to be implemented.

As shown above, the maintenance management menu decision method of some embodiments is the maintenance management menu decision method of the factory, and it has the step of predicting the remaining life of the maintenance target part based on the inspection result of the maintenance target part in contact with the fluid in the factory S4. The maintenance management menu decision method of some implementation forms has the ability to change the input factor value used in the evaluation of the remaining life of the maintenance target part by the life extension measures of the maintenance target part if the predicted remaining life is shorter than the allowable period Step S5 of re-predicting the remaining life at the time. The maintenance management menu decision method of some implementation forms has the step of drawing up a maintenance management menu for the factory including life extension measures if it is confirmed that the predicted remaining life is longer than the aforementioned allowable period. In this way, after confirming that the remaining life after adopting the life extension measures is longer than the allowable period, a maintenance management menu including the life extension measures is drawn up, so that the remaining life of the maintenance target part can be longer than the allowable period.

Among them, if the plant is a power plant and the fluid circulating in the piping is steam, as described above, after confirming that the remaining life after adopting the life extension measure is longer than the allowable period, draw up a maintenance management menu that includes the life extension measure, thereby The remaining life of the maintenance target part in contact with steam in the power plant can be longer than the allowable period.

The life extension measures to be implemented may be one of the above-mentioned multiple life extension measures, or a combination of multiple life extension measures. For example, as a result of reviewing with reference to Fig. 2, if it is determined that the temperature in the part to be maintained must be lowered by T°C so that the remaining life is longer than the allowable period, one of the above-mentioned multiple life extension measures can also be used , Lower the temperature in the part to be maintained by T°C. In addition, one of the above-mentioned multiple life extension measures can be used to reduce the temperature in the maintenance target area by t1°C, and other measures can be used to reduce the temperature in the maintenance target area by t2°C to reduce the temperature t1 The sum with t2 becomes T°C or higher. The point of view shown above is the same with regard to the reduction of stress in the part to be maintained.

If a plurality of life extension measures are combined, the measures for reducing the steam temperature and measures for reducing the steam pressure, which are measures for mitigating the operating conditions, may be combined as described above. In addition, if multiple life extension measures are combined, it is also possible to combine stress relaxation measures and local cooling as local measures, and combine multiple measures with each other in local measures. In addition, if a combination of multiple life extension measures is combined, it is also possible to combine operating conditions relaxation measures and local measures. By combining operating condition mitigation measures and local measures, the amount of changes in the operating conditions of the factory can be suppressed, and the impact on the operation of the plant can be suppressed, and local measures can be simplified.

Among them, when implementing life extension measures, the occurrence of lost benefits or increased costs are considered. Therefore, it is advisable to calculate in advance to what extent the benefits or costs will increase due to the implementation of life extension measures. For example, if the temperature or pressure of the steam is reduced due to the measures for mitigating operating conditions, and the operating efficiency in the plant is reduced, the parameters including the degree of reduction of the operating efficiency and the loss of benefits during the implementation of the measures for mitigating operating conditions will occur. In addition, for example, due to local countermeasures, costs for implementing the countermeasures occur. The cost system includes the cost of equipment and materials required to prepare the countermeasure, or the construction cost for the countermeasure. In addition, if the plant's suspension period is extended due to the implementation of this countermeasure, the plant will lose profits due to the extension of the suspension period.

In step S6 of the above-mentioned drafting maintenance management menu, if there are multiple life extension measures that can extend the remaining life to the above allowable period, considering the above circumstances, convert the impact of applying at least one of the multiple life extension measures to the amount, and consider The result of the amount conversion determines the maintenance management menu. Thereby, it is possible to make the remaining life of the maintenance target part longer than the allowable period while suppressing the economic loss caused by the implementation of life extension measures.

For example, compared with the case of separately implementing the operating condition mitigation measures and local measures, the life extension measures can be formed as operating conditions mitigation measures and local measures selected in such a way that the sum of lost benefits and increased costs is reduced. The combination. That is, for example, in the operating condition mitigation countermeasures, the operating conditions of the factory are changed, so the operating efficiency of the factory is reduced as described above, and there is a case where a loss of profit occurs. Generally speaking, the wider the change of the operating conditions of the factory, the more the operating efficiency of the factory decreases and the loss of profit tends to increase. In addition, in local countermeasures, generally speaking, the more effective the countermeasure is, the more the cost of countermeasures tends to increase. Therefore, for example, a combination of operating condition mitigation measures and local measures can result in lost profits due to changes in the operating conditions of the plant, but the cost increase due to implementation of local measures can be suppressed. In other words, by combining operating condition mitigation measures and local measures, although the cost of implementing local measures will be incurred, the lost profits due to changes in the operating conditions of the plant can be reduced. Therefore, by appropriately selecting a combination of operating condition mitigation measures and partial measures, the sum of lost benefits and increased costs can be suppressed.

Combining measures to ease operating conditions and local measures is particularly effective when life extension measures are required for multiple locations. For example, consider a case where the remaining life of three locations is found to be shorter than the allowable period. Here, regarding these three locations, if it is desired to cope with temperature reduction as a countermeasure against operating conditions, it is determined that the temperature reduction required for location A is -100°C, location B is -50°C, and location C is -30°C. In addition, the following means (1) to (3) can be used as a countermeasure for life extension. Means (1) is a means to lower the steam temperature as the operating condition of the factory. In the method (1), the decrease in the vapor temperature is assumed to be -50°C as the limit. Among them, in the means (1), the lost benefit corresponding to the decrease in the steam temperature continues to occur during the implementation period of the means (1). Means (2) is the first means to locally lower the temperature. In the method (2), the temperature decrease amount is assumed to be -50°C as the limit. Among them, in the means (2), compared with the method (3) described later, the amount of temperature reduction is small, but the initial cost is small, and the maintenance cost to continue the means (2) is negligible. Means (3) is the second means to locally lower the temperature. In the method (3), the temperature decrease amount is assumed to be -100°C as the limit. Among them, in the means (3), compared with the above-mentioned means (2), the amount of temperature reduction is large, but the initial cost is expensive, and the maintenance cost for continuing the means (3) is negligible. Under this condition, an example of a table combining the combination type and the amount of temperature reduction for the life extension countermeasure is shown in FIG. 3. Type 1 in Figure 3 is the case where the means (1) is used to the maximum extent, type 3 is the case where the means (1) is not used, and type (2) is the middle case. Means (1) is a change in the operating conditions of the factory, and has an effect on all positions A to C. Means (2) and (3) are local countermeasures, and only have an effect at each position where countermeasures are implemented.

Specifically, in pattern 1, by means (1), the temperature of each position A to C is lowered by 50°C, and by means (2), the temperature of position A is further lowered by 50°C. Thereby, at the position A, the temperature is lowered by 100°C, and at the position B and the position C, the temperature is lowered by 50°C, respectively. In pattern 2, by means (1), the temperature of each position A to C is lowered by 30°C, and by means (2), the temperature of position B is further lowered by 20°C, and by means (3) , The temperature of position A is further reduced by 70°C. Thereby, at position A, the temperature drops by 100°C, at position B, the temperature drops by 50°C, and at position C, the temperature drops by 30°C. In pattern 3, by means (2), the temperature of position B is reduced by 50°C, and by means (2), the temperature of position C is lowered by 30 degrees, and by means (3), the temperature of position A The temperature drops by 100°C. Thereby, at position A, the temperature is reduced by 100°C, at position B, the temperature is reduced by 50°C, and at position C, the temperature is reduced by 30°C.

Which combination type is better, you can add the lost benefits caused by means (1) and the increased costs caused by means (2) and (3) for each type, and the result will be added Make comparisons to determine the most suitable combination.

(About monitoring content) Among them, in order to guarantee the remaining life extended by the life extension measures proposed as described above, if necessary, the plant is monitored in step S8 of monitoring the maintenance target part described later. Since the purpose is to guarantee the remaining life that is prolonged due to the above-mentioned life extension measures, the monitoring items and monitoring methods are formed as suitable for the proposed life extension measures among the monitoring items and methods listed below. . Therefore, in step S6 of drafting a maintenance management menu, a monitoring item and a monitoring method suitable for the planned life extension countermeasure are selected. Among them, the monitoring system includes monitoring performed during plant operation and monitoring performed when the plant is stopped.

In the monitoring performed during the operation of the plant, the temperature, pressure, deformation (strain), and the progress of cracking of the maintenance target part can be listed as monitoring items. The temperature monitoring method includes, for example, a thermocouple, a radiation thermometer, a temperature measurement by an infrared camera, etc., or a temperature measurement by an optical fiber. Among them, the temperature measurement by the optical fiber is a temperature measurement that uses the temperature dependence of the intensity of Raman scattered light in the optical fiber.

For the pressure monitoring method, for example, a pressure gauge installed in a factory can be used. The deformation (strain) monitoring method includes, for example, measurement by strain gauge, measurement by laser speckle strain gauge, displacement gauge side by image correlation method, creep button, Measurement by laser distance meter, displacement measurement by optical fiber displacement meter, etc. Here, the creep button refers to a method of setting a measurement point in advance in order to measure the creep strain that occurs during operation. The key system shows the shape of the measuring point. Specifically, it is a means to add protrusions on both sides with a weld line sandwiched therebetween, measure the distance between the protrusion and the protrusion as an initial value, and follow the change over the years of the distance.

In terms of monitoring methods for the progress of cracks, for example, the detection of acoustic emission, the potential difference method for detecting changes in resistance due to the progress of cracks, and the detection of changes in magnetic properties due to the progress of cracks Methods, strain measurement, etc.

In the monitoring performed during plant shutdown, the temperature, deformation (strain), and the progress of cracking of the maintenance target part can be listed as monitoring items. The temperature monitoring method includes, for example, a method of estimating a temperature history by observing the tissue of the part to be maintained by the replication method, a method of estimating a temperature history from a small amount of samples obtained, and a method of aging tissue The method of estimating the temperature history based on the observation of, and the method of estimating the temperature history from the formation state of steam oxidation scale or the formation state of precipitates.

The monitoring method of deformation (strain) is as described above.

Regarding the monitoring method of crack progress, for example, if it is the surface of the maintenance target part, it can include: magnetic particle inspection, penetrating inspection, inspection by MT transfer method, eddy current inspection, etc. In addition, if it is the inside of the maintenance target part, it can include: ultrasonic inspection by traditional UT method, ultrasonic inspection by TOFD method, ultrasonic inspection by guided wave, and phase array method Ultrasonic inspection, ultrasonic inspection by opening synthesis method, ultrasonic inspection by high frequency UT method, ultrasonic inspection by ultrasonic noise method, radiation inspection, etc.

(Step S7 of the maintenance management of the maintenance target part) In step S7 of the maintenance management of the maintenance target part, the maintenance management menu determined in step S3 of the maintenance management menu is determined, that is, the maintenance management menu including the life extension measures formulated in step S6 of the preparation of the maintenance management menu The maintenance management menu is used to perform the maintenance management steps of the maintenance target part.

(Step S8 for monitoring the maintenance target part) In step S8 of monitoring the maintenance target part, after performing the maintenance management in step S7 of performing maintenance management of the maintenance target part, a step of monitoring the maintenance target part is performed. In the monitoring performed in step S8 of monitoring the maintenance target part, the maintenance target part is monitored by the monitoring item and monitoring method selected in step S6 of preparing the maintenance management menu.

That is, in step S8 of monitoring the maintenance target part, the items that affect the input factor value used when re-estimating the remaining life are monitored, and it is judged whether or not the remaining life predicted is longer than the allowable period. The allowable range of monitoring items that should be met. By this, it can be judged whether the remaining life of the maintenance target part can be shorter than the allowable period. Therefore, if necessary, the life extension policy can be added to implement, etc., and the response can be made to be longer than the allowable period. .

As shown above, the maintenance management methods of the factories in several embodiments include: step S3 of determining the maintenance management menu of the factory; step S7 of maintenance management of the maintenance target part according to the maintenance management menu; and maintenance after the maintenance management Step S8 of monitoring the target part. As a result, by implementing life extension measures, the remaining life of the maintenance target part can be made longer than the allowable period, and the state of the maintenance target part during subsequent plant operation can be grasped.

Among them, if it is determined that the value of the monitoring item is out of the allowable range, a new life extension strategy is drawn up by re-implementing the above-mentioned step S5 of re-estimating the remaining life and step S6 of drawing up the maintenance management menu. That is, in some embodiments, if it is determined that the value of the monitoring item is out of the allowable range in the step of monitoring the maintenance target part, it is predicted that the input factor value will be changed by the new life extension measures of the maintenance target part. The step of new remaining life, that is, step S5 of re-predicting the remaining life. In addition, in some embodiments, if it is confirmed that the new remaining life is longer than the allowable period, the step of drawing up a maintenance management menu for the factory including a new life extension strategy, that is, step S6 of drawing up a maintenance management menu. As shown above, after confirming that the new remaining life after adopting the new life extension measures is longer than the allowable period, a maintenance management menu containing the new life extension measures is drawn up, so that the remaining life of the maintenance target part can be longer than the allowable period .

The present invention is not limited to the above-mentioned embodiment, and includes a form in which a modification is applied to the above-mentioned embodiment, or a form in which these forms are appropriately combined. For example, in the several embodiments described above, the maintenance target part is the welding part in the steam piping of a plurality of systems connecting the boiler and the steam turbine in the thermal power plant, but the maintenance target welding part is not limited to a part of the boiler. The maintenance management menu determination method and the maintenance management method of the factory of the present invention can be applied to various welded parts or parts other than the welded parts exposed to high temperature and high pressure.

L0, L1, L2‧‧‧equal life line

Fig. 1 is a diagram showing each process in the maintenance management method of a factory using the maintenance management menu decision method of several implementation forms. Fig. 2 is a graph in which the temperature of the maintenance target part is taken on the horizontal axis and the stress of the maintenance target part is taken on the vertical axis. Figure 3 is a table for explaining the combination of life extension measures and the amount of temperature reduction.

Claims (15)

A method for determining a maintenance management menu, which is a method for determining a maintenance management menu of a factory, and is characterized by: having: the maintenance target part of the factory in contact with the fluid obtained during the inspection carried out during the stop of the factory If the predicted remaining life is shorter than the allowable period, the above-mentioned maintenance target part’s life extension measures will be used to change the aforementioned maintenance target part’s life The step of re-predicting the aforementioned remaining life when the factor value used in the remaining life assessment is to be entered; and if it is confirmed that the aforementioned remaining life predicted again is longer than the aforementioned allowable period, then the aforementioned factory inspection after the current inspection Before starting again, draw up the steps of the maintenance management menu for the aforementioned factory including the aforementioned life extension measures. For example, the maintenance management menu determination method of the first item of the scope of patent application, wherein the aforementioned life extension measures include: the operation condition mitigation measures for reducing the load on the aforementioned maintenance target parts by changing the aforementioned factory operating conditions, or the aforementioned maintenance target At least one of the local countermeasures implemented at the site. If the maintenance management menu of item 2 of the scope of patent application determines the method, the Wherein, the step of re-predicting the remaining life includes: obtaining the input factor value changed by the aforementioned operating condition mitigation countermeasure or the aforementioned partial countermeasure, and then predicting the aforementioned remaining life based on the obtained input factor value step. For example, the maintenance management menu decision method of item 2 or item 3 of the scope of patent application, wherein the aforementioned life extension countermeasure is a countermeasure that combines the aforementioned operation condition relaxation countermeasure and the aforementioned partial countermeasure. For example, the maintenance management menu decision method of item 4 of the scope of patent application, in which the aforementioned life extension countermeasures are compared with the situation of separately implementing the aforementioned operating condition mitigation countermeasures and the aforementioned partial countermeasures, based on the sum of the lost benefits and increased costs. A combination of the aforementioned operating condition mitigation measures selected by the less mode and the aforementioned partial measures. For example, the maintenance management menu determination method of item 2 or item 3 of the scope of the patent application, wherein the aforementioned operating condition mitigation measures include: the aforementioned measures to reduce the temperature of the fluid in contact with the maintenance target part, or to reduce the pressure of the fluid At least one of the countermeasures. For example, the maintenance management menu determination method of item 2 or 3 of the scope of patent application, wherein the aforementioned local countermeasures include: local cooling of the aforementioned maintenance target part, local cooling of the aforementioned maintenance target part, stress relaxation countermeasures to relieve the stress in the aforementioned maintenance target part, Or damage that restores the damage in the aforementioned maintenance target part At least one of the recovery measures. For example, the maintenance management menu decision method of item 2 or 3 of the scope of the patent application, wherein the aforementioned local countermeasures include: reinforcement of the aforementioned maintenance target part or at least one of the modification of the restriction condition in the aforementioned maintenance target part as a mitigation The stress mitigation measures for the stress in the above-mentioned maintenance target part. For example, the maintenance management menu determination method of item 2 or 3 of the scope of patent application, wherein the aforementioned local countermeasures include at least repair welding of the aforementioned maintenance target part as a damage recovery countermeasure to restore the damage in the aforementioned maintenance target part. For example, the method for determining the maintenance management menu of any one of items 1 to 3 in the scope of the patent application, wherein, in the step of drawing up the maintenance management menu, if there is a plural number, the remaining life can be extended and the life span of the allowable period can be extended As a countermeasure, the effect of applying at least one of the aforementioned life extension countermeasures is converted into an amount, and the result of the amount conversion is considered to determine the maintenance management menu. For example, the maintenance management menu determination method of any one of items 1 to 3 in the scope of the patent application, wherein, in the step of re-estimating the remaining life, the review of the allowable period or the review of the input factor value is performed After at least one of the above, predict the aforementioned remaining life. For example, the maintenance management menu decision method of any one of items 1 to 3 of the scope of patent application, wherein the aforementioned factory is a power plant, and the aforementioned stream system steam. A maintenance management method for a factory, which is characterized by: having: the steps of determining the maintenance management menu of the aforementioned factory by the maintenance management menu determination method of any one of items 1 to 12 of the scope of patent application; The management menu includes the steps of performing the maintenance management of the aforementioned maintenance target part; and, after the aforementioned maintenance management, the step of monitoring the aforementioned maintenance target part. A maintenance management method of a factory, which is a maintenance management method of a factory equipped with steps to determine the maintenance management menu of the factory, characterized in that: in the step of deciding the maintenance management menu, the method is based on the fluid contact in the aforementioned factory The result of flaw detection inspection of the maintenance target part predicts the remaining life of the maintenance target part. If the predicted remaining life is shorter than the allowable period, the maintenance target part will be changed by the aforementioned maintenance target part life extension measures Re-predict the aforementioned remaining life when the input factor value used in the remaining life assessment of If it is confirmed that the predicted remaining life is longer than the aforementioned allowable period, a maintenance management menu for the aforementioned factory including the aforementioned life extension measures is drawn up. The aforementioned maintenance management method is additionally equipped: follow the aforementioned maintenance management menu to perform The step of the maintenance management of the aforementioned maintenance target part; and after the aforementioned maintenance management, the step of monitoring the aforementioned maintenance target part, in the aforementioned step of monitoring the maintenance target part, the monitoring is used to predict the remaining life For the item that the input factor value affects, it is determined whether it is out of the allowable range of the item that should be satisfied in order for the predicted remaining life to be longer than the allowable period. For example, the maintenance management method of the factory of the 14th patent application, which additionally includes: in the step of monitoring the maintenance target part, it is determined that the value of the aforementioned item is out of the aforementioned allowable range, and the new value of the maintenance target part is predicted Life extension measures to change the new remaining life when the aforementioned factor values are entered; and if it is confirmed that the aforementioned new remaining life is longer than the allowable period, formulate a maintenance management menu for the aforementioned factory that includes the aforementioned new life extension measures step.

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