JP7154783B2 - Apparatus for estimating remaining life of heat transfer tube, method for estimating remaining life, and program - Google Patents

Description

TECHNICAL FIELD The present invention relates to a remaining life estimation device for a heat transfer tube, a remaining life estimation method, and a program.

2. Description of the Related Art In a heat transfer tube provided in a boiler in a power plant, it is necessary to measure the outer shape of the heat transfer tube in order to determine whether it needs to be replaced or not. As a method of measuring the outer shape, there is a method of manually measuring the entire circumference of the heat transfer tube with a vernier caliper, and a three -dimensional measurement method of dividing the circumference of the heat transfer tube into multiple sides and measuring it with a measuring device. is used.

As an example of a three-dimensional measurement method, Patent Document 1 describes a method in which a surface shape of an object to be measured is measured to obtain three-dimensional measurement data, and the surface shape is evaluated (curvature, etc.) based on the measurement data. ) is disclosed.

JP 2015-227796 A

However, the method of manually measuring the entire circumferential surface of the heat transfer tube with a vernier caliper requires a huge amount of time and manpower. In addition, even in the three-dimensional measurement method, in order to measure the entire peripheral surface, multiple measurements must be performed at different angles with respect to one heat transfer tube, which requires labor and time.

The present invention has been made in view of such circumstances, and provides a remaining life estimation device for heat transfer tubes, a remaining life estimation method, and a program that can greatly shorten the measurement time of heat transfer tubes. With the goal.

An embodiment of a heat transfer tube shape estimation device according to some embodiments of the present invention is a heat transfer tube shape estimation device provided in a boiler in a power plant, wherein the outer shape of a predetermined side surface of the heat transfer tube and a best-fit shape estimating unit for estimating a best-fit shape that is circular or oval based on the measurement result of the measuring unit. is.

According to the above configuration, the outer shape of the predetermined side surface of the heat transfer tube is partially measured, and the best-fit shape, which is a circular or oval shape, is estimated. It is possible to greatly reduce the time required. Note that the oval shape includes an elliptical shape. Conventionally, when measuring the outer shape of a circular or oval shape such as a heat transfer tube, the method of manually measuring the entire peripheral surface with a vernier caliper or dividing the entire peripheral surface into multiple side surfaces with a measuring device has been used. A three-dimensional measurement method is used to measure the The method of manually measuring the entire peripheral surface with a vernier caliper required a huge amount of time and manpower, and the three-dimensional measurement method required multiple measurements for one heat transfer tube, which was time-consuming. . However, according to the configuration as described above, in order to estimate the best-fit shape, which is a circular shape or an oval shape, based on the measurement result of the partially measured outer shape of the predetermined side surface, the measured predetermined side surface The best fit shape can be obtained without measuring the other side. That is, it becomes unnecessary to measure the entire circumference of the heat transfer tube, and the measurement time of the heat transfer tube can be greatly shortened. Therefore, for example, the construction period itself such as inspection can be shortened, and the boiler stop period can be shortened.

In the above shape estimation device, the predetermined side surface of the heat transfer tube may be a side surface of the heat transfer tube on the upstream side of the high-temperature gas flow.

According to the configuration as described above, the measurement target portion of the heat transfer tube is the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow. In the heat transfer tubes provided in the boiler, the heat load is higher on the side on the upstream side of the high temperature gas flow than on the side on the downstream side of the high temperature gas flow. Presumed. Therefore, by measuring the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow and estimating the best-fit shape, it is possible to obtain the best-fit shape that reflects the deformation of the heat transfer tube due to the heat load.

In the above-described shape estimation device, the measurement unit may measure a heat transfer tube arranged upstream of a high-temperature gas flow in a group of heat transfer tubes arranged in the boiler.

According to the above configuration, in order to measure the heat transfer tubes arranged on the upstream side (preferably the most upstream side) of the high-temperature gas flow in the heat transfer tube group arranged in the boiler, each of the heat transfer tube groups The shortest remaining life among the remaining lives of the heat transfer tubes can be easily obtained. The remaining life of the heat transfer tube can be evaluated by the outer diameter distortion (or expansion amount), and the main cause of the outer diameter distortion is thermal expansion due to high temperature gas. For this reason, by measuring the heat transfer tube placed upstream of the high temperature gas flow exposed to the highest temperature gas, data on the heat transfer tube with the largest outer diameter distortion and short remaining life can be obtained. be able to. In other words, by grasping the shortest remaining life, it is possible to efficiently plan the inspection cycle and replacement cycle of the heat transfer tubes.

In the shape estimating device described above, the best-fit shape estimating unit may estimate the best-fitting shape by applying a least-squares method based on the measurement result of the measuring unit.

According to the configuration as described above, the best-fit shape is estimated by applying the least-squares method based on the measurement result of the measuring unit, so the optimum approximate shape can be effectively obtained.

In one embodiment of the heat transfer tube remaining life estimation device according to some embodiments of the present invention, the heat transfer tube is approximately An expansion outer shape estimating unit for estimating an expansion outer shape assumed in the case of maximum expansion, and a remaining life estimation for estimating the remaining life of the heat transfer tube based on the initial outer shape and the expansion outer shape of the heat transfer tube. and a remaining life estimation device for heat transfer tubes.

According to the above configuration, since the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum is estimated, it is possible to estimate a substantially worst case as the expansion outer shape, and the estimated expansion outer shape By estimating the remaining life of the heat transfer tube using the shape, it is possible to prevent the remaining life of the heat transfer tube from being overestimated and to suppress the risk of damage or the like occurring in the heat transfer tube.

In the remaining life estimation device, the remaining life estimation unit calculates the external distortion of the expanded external shape with respect to the initial external shape of the heat transfer tube, and uses a preset relationship between the external diameter distortion and the life consumption rate, The remaining life of the heat transfer tube may be estimated.

According to the configuration as described above, it is possible to easily estimate the remaining life of the heat transfer tube using the preset relationship between the outer diameter distortion and the life consumption rate.

In the remaining life estimation device, the outer shape of the heat transfer tube is a circular shape, the best-fit shape is a circular shape, and the expansion outer shape estimating unit combines the measurement result of the measuring unit with the best-fit shape The expanded outer shape of the heat transfer tube may be estimated by calculating the maximum radial error in and and adding the value obtained by doubling the maximum error to the diameter of the best-fit shape.

According to the above configuration, the maximum radial error between the measurement result of the measurement unit and the best-fit shape is used to estimate the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum. , the worst case can be estimated as the dilated outer shape. Therefore, it is possible to prevent the remaining life of the heat transfer tube from being overestimated, and to suppress the risk of damage or the like occurring in the heat transfer tube.

In the remaining life estimation device, the outer shape of the heat transfer tube is a circular shape, the best-fit shape is a circular shape, and the expansion outer shape estimating unit combines the measurement result of the measuring unit with the best-fit shape Calculate the average value and standard deviation of the errors in the radial direction, and double the error of the deviation value preset in the range above the value obtained by adding twice the standard deviation to the average value The best The expanded outer shape of the heat transfer tube may be estimated by adding to the diameter of the fitted shape.

According to the configuration described above, using the average value and standard deviation of the radial error between the measurement result of the measurement unit and the best-fit shape, the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum is determined. Since it was decided to estimate, it is possible to estimate substantially the worst case as the expansion outer shape. Therefore, it is possible to prevent the remaining life of the heat transfer tube from being overestimated, and to suppress the risk of damage or the like occurring in the heat transfer tube.

In the remaining life estimation device, the outer shape of the heat transfer tube is an elliptical shape, the best-fit shape is an elliptical shape, and the expansion outer shape estimating unit includes, among the measurement results obtained by the measuring unit, Identifying a measurement point that maximizes the distance from the center point in the best-fit shape, enlarging the best-fit shape so that the measurement point coincides with the circumference, and expanding the best-fit shape The expanded outer shape of the heat tube may be estimated.

According to the configuration described above, the measurement point with the maximum distance from the center point in the best-fit shape is identified, the best-fit shape is enlarged so that the measurement point coincides with the circumference, and the Since the expansion outer shape of the heat transfer tube, which is the shape, is estimated, the worst case can be estimated as the expansion outer shape. Therefore, it is possible to prevent the remaining life of the heat transfer tube from being overestimated, and to suppress the risk of damage or the like occurring in the heat transfer tube.

One embodiment of a heat transfer tube shape estimation method according to some embodiments of the present invention is a heat transfer tube shape estimation method provided in a boiler in a power plant, wherein the outer shape of a predetermined side surface of the heat transfer tube and a best-fit shape estimation step of estimating a best-fit shape that is circular or oval based on the measurement results of the measurement step. be.

According to one embodiment of the program according to some embodiments of the present invention, a computer of a heat transfer tube shape estimating device provided in a boiler in a power plant partially estimates the outer shape of a predetermined side surface of the heat transfer tube. A program for executing a measurement process for measuring, and a best-fit shape estimation process for estimating a best-fit shape, which is circular or oval, based on the measurement result of the measurement process.

According to some embodiments of the present invention, it is possible to significantly shorten the measurement time of heat transfer tubes.

1 is a diagram showing a schematic configuration of an example of a remaining life estimation device according to some embodiments of the present invention; FIG. It is an example of measurement in the circumferential direction of the heat transfer tube by the measurement unit of the remaining life estimation device according to some embodiments of the present invention. It is an example of measurement in the axial direction of a heat transfer tube by the measurement unit of the remaining life estimation device according to some embodiments of the present invention. FIG. 4 is a diagram showing the relationship between an example of the outer shape of heat transfer tubes in a boiler and the flow of high-temperature gas. FIG. 4 is a diagram showing heat transfer tube groups and high-temperature gas flows in a boiler; It is the figure which illustrated the relationship of the measurement result by the measurement part of the life expectancy estimation apparatus which concerns on some embodiment of this invention, and a best-fit shape. It is the graph which showed the relationship between the outer-diameter strain and the life consumption rate in the life expectancy estimation apparatus which concerns on some embodiment of this invention. It is the figure which showed the flowchart of the life expectancy estimation method in the life expectancy estimation apparatus which concerns on some embodiment of this invention.

Below, one embodiment of the remaining life estimation device 1 according to some embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a remaining life estimation device 1. As shown in FIG. As shown in FIG. 1, the remaining life estimation device 1 includes a measurement unit 2, a best-fit shape estimation unit 3, an expansion outer shape estimation unit 4, and a remaining life estimation unit 5 as main components. Note that the measuring unit 2 and the best-fit shape estimating unit 3 may be provided as a shape estimating device.

In addition, the best-fit shape estimating unit 3, the expanded outer shape estimating unit 4, and the remaining life estimating unit 5 are provided as one information processing unit. Memory), a computer-readable recording medium, and the like. A series of processes for realizing various functions described later is recorded in the form of a program on a recording medium, etc., and the CPU reads this program into RAM, etc., and executes processing and arithmetic processing of information. Various functions, which will be described later, are realized. The best-fit shape estimator 3, the expanded outer shape estimator 4, and the remaining life estimator 5 may be divided into a plurality of information processors.

The measuring unit 2 is a measuring instrument that partially measures the outer shape of a predetermined side surface of the heat transfer tube. Specifically, the measuring unit 2 is a measuring instrument such as a line sensor, and is capable of measuring the outer shape of the heat transfer tube, which is the object to be measured. As the measuring unit 2, any other three-dimensional measuring instrument may be used as long as it is a measuring instrument capable of measuring the outer shape of the heat transfer tube, or a vernier caliper or the like may be used to measure the outer shape of the heat transfer tube. good. In this embodiment, the heat transfer tube is assumed to have a cylindrical shape (a cross section in a plane perpendicular to the central axis, that is, a circular cross section). A case where the heat transfer tube has an oblong cylindrical shape (a cross section in a plane perpendicular to the central axis, that is, an oval cross section) will be described later as another embodiment.

2 and 3 are examples of measurement of a heat transfer tube by the measurement unit 2. FIG. FIG. 2 shows an example of measuring the outer shape of a heat transfer tube in the circumferential direction. In addition, the heat transfer tube A shows an example of an outer shape (an example of thermal expansion) in the circumferential direction. FIG. 3 shows an example of measuring the outer shape of the heat transfer tube in the axial direction (the direction of the central axis). In addition, in the measurement examples of FIGS. 2 and 3 , the predetermined side surface of the heat transfer tube A is measured by the measurement unit 2 . In this embodiment, it is assumed that a line sensor is used as the measurement unit 2 . Therefore, the measuring unit 2 measures the circumferential outer shape of a predetermined side surface of the heat transfer tube at a predetermined position in the axial direction of the heat transfer tube by performing measurement as shown in FIG. 2 . By moving the measuring unit 2 in the axial direction of the heat transfer tube as shown in FIG. 3, the circumferential outer shape of a predetermined side surface of the heat transfer tube is measured at each position in the axial direction of the heat transfer tube. That is, the outer shape of the heat transfer tube in the circumferential direction as shown in FIG. 2 is measured by moving the heat transfer tube in the axial direction as shown in FIG. In FIGS. 2 and 3, the measurement unit 2 may target one heat transfer tube (for example, heat transfer tube A) in one measurement, or may target a plurality of heat transfer tubes (for example, heat transfer tube A, B, and C) may be targeted.

Further, for measurement of each position in the axial direction of the heat transfer tube as shown in FIG. 3, the number of divisions in the axial direction of the heat transfer tube is set in advance. That is, the measuring unit 2 measures the outer shape in the circumferential direction of the predetermined side surface of the heat transfer tube for the number of divisions set in advance by moving in the axial direction of the heat transfer tube. The number of divisions of the heat transfer tube in the axial direction is set according to the desired resolution for the outer shape of the heat transfer tube. For a specific heat transfer tube, if it is possible to determine in advance a range in which the heat load is particularly high in the axial direction of the heat transfer tube (for example, near the center of the heat transfer tube), only this range is measured, and the axis in this range is measured. Measurements may be taken at each position in the direction. In addition, when a position with a particularly high heat load in the axial direction of the heat transfer tube (for example, the center of the heat transfer tube) can be determined in advance, only this position is measured, and only this position is measured. It is also possible to measure the outer shape in the circumferential direction on the side surface of the .

The predetermined side surface of the heat transfer tube is the side surface of the heat transfer tube on the upstream side of the high temperature gas flow. FIG. 4 is a diagram showing a relationship between a high-temperature gas flow in a boiler and an example of the outer shape (example of thermal expansion) of a heat transfer tube. In the boiler, the high temperature gas flows in a certain direction, so a particularly high heat load is applied to the side surfaces of the heat transfer tubes that are exposed to the high temperature gas. For this reason, the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow is particularly bulged and deformed.

Specifically, if the angle of the high-temperature gas flow with respect to the central axis of the heat transfer tube is 0 degrees, then in the circumferential direction of the heat transfer tube, for example, the heat transfer angle is about ±60 degrees (120 degrees in total) with respect to the high-temperature gas flow. The outer shape of the heat tube bulges particularly unevenly. For this reason, the measurement unit 2 does not measure the entire peripheral surface of the heat transfer tube, but partially measures a predetermined side surface of the heat transfer tube, thereby measuring the outer shape of the heat transfer tube with a high degree of thermal expansion. can do.

The predetermined side surface of the heat transfer tube is the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow, and is arbitrarily set within a range measurable by the measurement unit 2 in one measurement. For example, when the measurable range of the measurement unit 2 in one measurement is 120 degrees in the circumferential direction of the heat transfer tube, the predetermined side surface of the heat transfer tube is as shown in FIG. The sides are set at ±60 degrees with respect to the hot gas flow in the circumferential direction. That is, in this embodiment, only the outer shape of the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow is measured in one measurement without performing multiple measurements at different angles for one heat transfer tube. there is

Note that the measurement unit 2 may measure only the heat transfer tube or the heat transfer tube group arranged on the upstream side of the high-temperature gas flow in the heat transfer tube group arranged in the boiler. FIG. 5 is a diagram illustrating heat transfer tube groups arranged in a boiler and the flow of hot gas. As shown in FIG. 5, heat transfer tubes used in boilers in power plants are exposed to hot gases flowing within the boiler. In particular, the heat transfer tube group G arranged on the upstream side of the hot gas flow is exposed to the hot gas in a higher temperature state and is subjected to a high heat load. In a boiler in a power plant, heat is exchanged between high-temperature gas and boiler water flowing through heat transfer tubes, so the temperature of the high-temperature gas decreases toward the downstream side of the high-temperature gas flow. In other words, the heat load applied to the heat transfer tubes located downstream of the high-temperature gas flow is lower. For example, in FIG. 5, the heat transfer tube group G1 on the upstream side of the high temperature gas flow is more deformed due to thermal expansion than the heat transfer tube group G2 on the downstream side of the high temperature gas flow. It is estimated to be. Therefore, in the heat transfer tube groups arranged in the boiler, it is presumed that the higher the heat transfer tube group arranged on the upstream side of the high-temperature gas flow, the higher the heat load is applied and the larger the deformation. For this reason, instead of measuring all the heat transfer tube groups arranged in the boiler, measurement is performed only for the heat transfer tube group (for example, the heat transfer tube group G1) arranged on the upstream side of the high temperature gas flow. good too. By doing so, it is possible to obtain information on the outer shape of the most thermally deformed (degraded) heat transfer tube without measuring all the heat transfer tubes. That is, the measuring unit 2 is arranged so as to be able to measure only a predetermined heat transfer tube or a predetermined heat transfer tube group arranged upstream of the high-temperature gas flow in the heat transfer tube group arranged in the boiler. may

The best-fit shape estimator 3 estimates a best-fit shape, which is circular or elliptical, based on the result of measurement by the measuring unit 2 . Specifically, the best-fit shape estimation unit 3 estimates the best-fit shape by applying the least-squares method based on the measurement result of the outer shape in the circumferential direction of the predetermined side surface of the heat transfer tube by the measurement unit 2. . That is, since the measurement unit 2 measures the outer shape in the circumferential direction of the predetermined side surface of the heat transfer tube for the number of divisions set in advance in the axial direction of the heat transfer tube, the best-fit shape estimation unit 3 The best-fit shape for the number of divisions determined is estimated. In the present embodiment, a case in which the least squares method is used to estimate the best-fit shape will be described. It is also possible to use a method of algebraically obtaining a circle passing through. In this embodiment, a case where a circular best-fit shape is used will be described as an example. A case of using an oval best-fit shape will be described later as another embodiment.

FIG. 6 is a diagram exemplifying the relationship between the measurement result of the measurement unit 2 and the best-fit shape. In FIG. 6, L1 is the initial outer shape (outer shape in the circumferential direction (cross section)), which is the outer shape of the heat transfer tube before use, and L2 is the measurement result (measurement point group) measured by the measurement unit 2. , L3 indicate the best-fit shape (best-fit circle) estimated by the best-fit shape estimator 3 . That is, in the example shown in FIG. 6, the heat transfer tube having the initial outer shape L1 expands (deforms) due to the heat load due to the high-temperature gas, and has an outer shape like L2.

The best-fit shape estimation unit 3 applies the method of least squares to each measurement point of the measurement result L2 by the measurement unit 2, and estimates the best-fit shape L3 so that the sum of squares of errors is minimized. Specifically, the best-fit shape estimating unit 3 determines that the outer shape of the heat transfer tube other than the predetermined side surface measured by the measuring unit 2 is the same as the outer shape of the predetermined side surface of the heat transfer tube measured by the measuring unit 2. Estimate the outer shape of the entire peripheral surface of the heat transfer tube assuming that there is, and estimate the approximate circle by the least squares method. For example, when the outer shape of the heat transfer tube at 120 degrees in the circumferential direction is measured by the measuring unit 2, the portion other than 120 degrees in the circumferential direction measured by the measuring unit 2 has the same outer shape as the outer shape measured by the measuring unit 2. Assuming that the heat transfer tube has a shape, the outer shape of the entire peripheral surface of the heat transfer tube is estimated. The best-fit shape estimator 3 applies the method of least squares to the estimated outer shape of the entire circumferential surface of the heat transfer tube to estimate an approximate circle (best-fit shape).

The expanded outer shape estimator 4 estimates an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum, based on the measurement result of the measurement unit 2 and the best-fit shape estimated by the best-fit shape estimator 3. . Specifically, the expansion outer shape estimating unit 4 determines the maximum radial error between the measurement result of the circumferential outer shape of the predetermined side surface of the heat transfer tube by the measuring unit 2 and the best-fit shape corresponding to the measurement result. and adding the value obtained by doubling the maximum error to the diameter of the best fit shape, the expanded outer shape of the heat transfer tube is estimated. That is, the measurement unit 2 measures the outer shape in the circumferential direction of a predetermined side surface of the heat transfer tube for a predetermined number of divisions in the axial direction of the heat transfer tube, and the best-fit shape estimation unit 3 measures the predetermined division number. Since several best-fit shapes are estimated, the inflated outer shape estimator 4 estimates the inflated outer shape corresponding to each of the preset division number of best-fit shapes.

As shown in FIG. 6, the best-fit shape estimated by the best-fit shape estimation unit 3 is an average circle with respect to the measurement result of the measurement unit 2, so the most bulging portion is not reflected. Therefore, if the remaining life is estimated using the best-fit shape, there is a possibility that the estimated remaining life will be longer than the actual remaining life. have a nature. Therefore, the expanded outer shape estimator 4 estimates an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum.

As shown in FIG. 6, when the heat transfer tube thermally expands to the outer shape L2, the best-fit shape is estimated as L3. At this time, the measurement point at which the radial error between the measurement result of the measurement unit 2 and the best-fit shape is maximum is the point P1, and the maximum error is the error Rerr. Since the point P1 is the point where the heat transfer tube expands the most due to thermal expansion, it is estimated to be the most degraded measurement point. Therefore, by adding the value obtained by doubling the error Rerr to the diameter of the best-fit shape, it is possible to estimate the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum.

In addition, the expansion outer shape estimation unit 4 calculates the average value and standard deviation of the radial error between the measurement result by the measurement unit 2 and the best-fit shape, and the value that is equal to or greater than the average value plus twice the standard deviation The expanded outer shape of the heat transfer tube may be estimated by adding the value obtained by doubling the error of the deviation value preset in the range to the diameter of the best-fit shape. Specifically, first, radial errors are calculated for each measurement group of measurement results by the measuring unit 2 and the best-fit shape estimated by the best-fit shape estimating unit 3 . Then, an average value and a standard deviation are calculated for each calculated error. Then, an error corresponding to a preset deviation value is calculated. Here, the preset deviation value is set in advance in a range equal to or greater than the value obtained by adding twice the standard deviation to the average value. The range above the value obtained by adding twice the standard deviation to the average value is the range that includes the highest 2.5% of the calculated errors, and the deviation value set in advance within this range The corresponding error is an error that has approximately the maximum value among the calculated errors. That is, by adding the value obtained by doubling the error corresponding to the preset deviation value to the diameter of the best-fit shape, it is possible to estimate the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum. can.

The remaining life estimating unit 5 estimates the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube. Specifically, the remaining life estimator 5 calculates the external distortion of the expansion external shape with respect to the initial external shape of the heat transfer tube, and evaluates the remaining life based on the calculated external distortion. That is, since the expansion outer shape estimating unit 4 estimates the expansion outer shape for the preset number of divisions, the remaining life estimating unit 5 calculates the outer shape distortion for each of the estimated plural expansion outer shapes. Calculate the remaining life using the largest outer diameter distortion. Therefore, the remaining life can be estimated based on the portion of the heat transfer tube that is estimated to have thermally expanded (degraded) the most.

The external distortion is obtained by dividing the difference (D1-D0) between the diameter D1 of the circle of the expanded external shape and the diameter D0 of the circle of the initial external shape of the heat transfer tube by the diameter D0 of the circle of the initial external shape of the heat transfer tube. The resulting quotient is ((D1-D0)/D0). That is, the outer diameter strain is an index representing how much the heat transfer tube has deformed (expanded) from the initial outer shape, and indicates the degree of deterioration.

FIG. 7 is a graph illustrating the relationship between outer diameter distortion and life consumption rate. Note that the life consumption rate is defined as t/tr, where t is the elapsed time up to the present, and tr is the rated time at which creep fracture is estimated to occur in the heat transfer tube. That is, the life consumption rate indicates how much of the estimated creep fracture time has passed since the heat transfer tube was used. The remaining life estimator 5 uses the calculated outer diameter strain and the graph shown in FIG. 7 to calculate the remaining life of the heat transfer tube. Specifically, the remaining life estimator 5 first calculates the life consumption rate from the largest outer diameter strain among the calculated outer diameter strains using the graph shown in FIG. Then, the remaining life is evaluated from the calculated life consumption rate. That is, the time from the life consumption rate to the rated time at which creep failure is estimated to occur is evaluated. For example, when the rated time tr at which creep rupture is estimated to occur in the heat transfer tube is set to 10 years (the time from the start of use until creep rupture is estimated to occur), the outer diameter strain is 1.0 %, and the life consumption rate is assumed to be 70% when the outer diameter strain is 1.0%. In such a case, the estimated time until the rated time at which creep fracture occurs is estimated to be 10 years × 0.3 = 3 years as the remaining life from 1 - life consumption rate 0.7 = 0.3. be done. That is, it is estimated that creep fracture will not occur in the measured heat transfer tubes for another three years.

Next, a method for estimating remaining life by the remaining life estimating device 1 described above will be described with reference to FIG. The flow shown in FIG. 8 is executed, for example, when the user of the remaining life estimation device 1 inputs a command to start measurement.

First, the outer shape of a predetermined side surface of the heat transfer tube is measured (S101). That is, the measurement unit 2 is used to measure the outer shape of the side surface of the heat transfer tube that is set in advance as the side surface on the upstream side of the high-temperature gas flow. Note that in the present embodiment, a predetermined side surface of the entire peripheral surface of the heat transfer tube is partially measured.

Next, a best-fit shape is estimated based on the measurement results (S102). That is, the best-fit shape estimation unit 3 applies the method of least squares to the measurement results of the measurement unit 2 to calculate a best-fit shape (for example, a best-fit circle).

Next, an expansion outer shape assumed when the heat transfer tube expands substantially to the maximum is estimated (S103). That is, the expansion outer shape estimation unit 4 expands the best-fit shape (for example, the best-fit circle) based on the measurement point estimated to have expanded substantially to the maximum among the measurement results of the measurement unit 2, so that the heat transfer tube is Estimate an expansion outer shape (for example, a circular shape) that is assumed when substantially maximal expansion occurs.

Next, the remaining life of the heat transfer tube is estimated based on the initial outer shape and the expanded outer shape of the heat transfer tube (S104). That is, the outer diameter strain is calculated based on the initial outer shape and the expanded outer shape of the heat transfer tube, and the life consumption rate is calculated using the outer diameter strain-life consumption rate curve as shown in FIG. to estimate

Since the remaining life is estimated based on the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum, it is possible to suppress the remaining life from being estimated long, and the user of the remaining life estimation device 1 can be more A safe tube replacement cycle can be planned.

Next, another embodiment of the remaining life estimation device 1 according to some embodiments of the present invention will be described. In the above embodiment, the case where the heat transfer tube has a cylindrical shape (the cross section in the plane perpendicular to the central axis, that is, the cross section is circular) and a circular best-fit shape is used. A case where the heat tube has an elliptical shape (cross section in a plane perpendicular to the central axis, ie, an elliptical cross section) and an elliptical best-fit shape is used will be described. Note that the oval shape includes an elliptical shape, a square with rounded corners, and the like. Specifically, in the present embodiment, the case where the heat transfer tube has an elliptical cylindrical shape (the cross section in the plane perpendicular to the central axis, that is, the cross section has an elliptical shape) and an elliptical best-fit shape is used will be described. Whether the shape of the heat transfer tube is cylindrical or elliptical (elliptical), and whether the best-fit shape is circular or elliptical (elliptical), depends on the remaining life estimation device 1. It shall be entered by the user as an initial setting. That is, the remaining life estimation device 1 can cope with both the cylindrical shape and the long cylindrical shape of the heat transfer tube.

The best-fit shape estimation unit 3 in this embodiment estimates a best-fit shape (best-fit ellipse) by applying the method of least squares based on the measurement result of the measurement unit 2 . Specifically, the best-fit shape estimating unit 3 determines that the outer shape of the heat transfer tube other than the predetermined side surface measured by the measuring unit 2 is the same as the outer shape of the predetermined side surface of the heat transfer tube measured by the measuring unit 2. Estimate the outer shape of the entire peripheral surface of the heat transfer tube assuming that there is, and estimate the approximate ellipse by the least squares method.

The inflated outer shape estimating unit 4 in this embodiment identifies, among the measurement results obtained by the measuring unit 2, the measurement point at which the distance from the center point in the best-fit shape is the maximum, and the measurement point is aligned with the circumference. The best-fit shape is enlarged, and the expanded outer shape of the heat transfer tube, which is similar to the best-fit shape, is estimated. Specifically, the inflated outer shape estimating unit 4 first identifies, among the measurement results obtained by the measuring unit 2, the measurement point that has the maximum distance from the center point of the ellipse that is the best-fit shape. The measurement point at which the distance from the central point of the ellipse, which is the best-fit shape, is the maximum is the point that is most deformed by the heat load due to the high-temperature gas, and is presumed to be the most deteriorated. Therefore, the best-fit shape is enlarged while maintaining the similarity so that the identified measurement points match the circumference, and the expanded outer shape is estimated. That is, the inflated outer shape includes on the circumference the measurement point at which the distance from the center point of the ellipse, which is the best-fit shape, is the maximum, and is similar to the best-fit shape.

The remaining life estimator 5 in this embodiment estimates the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube. Specifically, the remaining life estimating unit 5 calculates the outer shape strain of the expanded outer shape with respect to the initial outer shape of the heat transfer tube, for example, using the major axis of the ellipse, and based on the calculated outer shape strain, the remaining life evaluation. That is, the remaining life estimating unit 5 calculates the outer strain for each of the estimated multiple expanded outer shapes, and uses the largest outer diameter strain to evaluate the remaining life.

In addition, the outer shape distortion is the difference (D1′−D0′) between the major axis D1′ of the ellipse of the expanded outer shape and the major axis D0′ of the ellipse in the initial outer shape of the heat transfer tube. is the quotient ((D1'-D0')/D0') obtained by dividing by the long axis D0'. In addition, the external distortion can also be expressed as ((L−π·D0′)/(π·D0′)) using the length L of the circumference of the ellipse of the expanded external shape. Note that π·D0′ may be the length L′ of the circumference of the ellipse in the initial external shape of the heat transfer tube. The length L of the circumference of the ellipse can be calculated using the following equation (1) or equation (2) which is an approximation of equation (1).

In equations (1) and (2), a is the major axis of the ellipse of the expanded outer shape, and b is the minor axis of the ellipse of the expanded outer shape (a≧b). Also, in the equation (1), e is the eccentricity.

In this embodiment, when the initial outer shape of the heat transfer tube is circular, the best-fit shape is also circular, and when the initial outer shape of the heat transfer tube is oval, the best-fit shape is also oval. However, depending on the definition of outer diameter distortion, if the initial outer shape of the heat transfer tube is circular, the best fit shape is oval, or the initial outer shape of the heat transfer tube is oval In addition, it is also applicable when the best-fit shape is circular.

As described above, according to the remaining life estimation device 1 according to the present embodiment, the best fit shape, which is a circular shape or an oval shape, is determined based on the measurement result of the external shape of the predetermined side surface that is partially measured. Because of the estimation, the best-fit shape can be obtained without measuring sides other than the measured side. That is, it becomes unnecessary to measure the entire circumference of the heat transfer tube, and the measurement time of the heat transfer tube can be greatly shortened. Therefore, for example, the construction period itself such as inspection can be shortened, and the boiler stop period can be shortened.

In addition, in the heat transfer tubes provided in the boiler, the heat load on the side surface on the upstream side of the high temperature gas flow is higher than the side surface on the downstream side of the high temperature gas flow, so the heat transfer tube is deformed more by the heat load. presumed to be Therefore, by estimating the best-fit shape with the side surface of the heat transfer tube on the upstream side of the high-temperature gas flow as the measurement target point for the heat transfer tube, it is possible to obtain the best-fit shape that reflects the deformation of the heat transfer tube due to the heat load. can be done.

In addition, by measuring the heat transfer tubes arranged on the upstream side (preferably the most upstream side) of the high-temperature gas flow in the heat transfer tube group arranged in the boiler, each heat transfer tube in the heat transfer tube group The shortest remaining life among the remaining lives can be easily obtained. The remaining life of the heat transfer tube can be evaluated by the outer diameter distortion (or expansion amount), and the main cause of the outer diameter distortion is thermal expansion due to high temperature gas. For this reason, by measuring the heat transfer tube placed upstream of the high temperature gas flow exposed to the highest temperature gas, data on the heat transfer tube with the largest outer diameter distortion and short remaining life can be obtained. be able to. In other words, by grasping the shortest remaining life, it is possible to efficiently plan the inspection cycle and replacement cycle of the heat transfer tubes.

In addition, since the best-fit shape is estimated by applying the least squares method based on the measurement result of the measuring unit 2, the optimum approximate shape can be effectively obtained.

In addition, since it was decided to estimate the expansion outer shape assumed when the heat transfer tube expands substantially to the maximum, it is possible to estimate the approximate worst case as the expansion outer shape, and the estimated expansion outer shape can be used to estimate the heat transfer tube. By estimating the remaining life, it is possible to avoid estimating the remaining life of the heat transfer tube too long, and to suppress the risk of damage or the like occurring in the heat transfer tube.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention.

For example, in the present embodiment, the remaining life estimation device 1 includes a measuring unit 2, a best-fit shape estimating unit 3, an expanded outer shape estimating unit 4, and a remaining life estimating unit 5. However, the measuring unit 2 and the best-fit shape estimating unit 3 may be configured as a single unit as a shape estimating device that estimates a best-fitting shape.

1: Remaining life estimation device 2: Measurement unit 3: Best fit shape estimation unit 4: Expansion outer shape estimation unit 5: Remaining life estimation unit

Claims (11)

A shape estimation device for a heat transfer tube provided in a boiler in a power plant,
a measuring unit that measures the outer shape of a partial predetermined side surface of the entire peripheral surface of the heat transfer tube;
Best fit for estimating a best-fit shape, which is circular or oval, for the outer shape of the heat transfer tube including the predetermined side surface and side surfaces other than the predetermined side surface based on the measurement result by the measurement unit. a shape estimation unit;
an expanded outer shape estimating unit that estimates an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum based on the result of measurement by the measuring unit and the best-fit shape;
a remaining life estimating unit that estimates the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube;
Remaining life estimation device for heat transfer tubes. 2. The apparatus for estimating the remaining life of heat transfer tubes according to claim 1, wherein the predetermined side surface of the heat transfer tube is a side surface of the heat transfer tube on the upstream side of the high-temperature gas flow. 3. The heat transfer tube remaining life estimation device according to claim 1 or 2, wherein the measurement unit measures a heat transfer tube arranged upstream of a high-temperature gas flow in a group of heat transfer tubes arranged in the boiler. 4. The heat transfer tube surplus according to any one of claims 1 to 3, wherein the best-fit shape estimating unit estimates the best-fit shape by applying a least squares method based on the measurement result of the measuring unit. Life expectancy estimator. The remaining life estimating unit calculates the outer shape distortion of the expanded outer shape with respect to the initial outer shape of the heat transfer tube, and uses a preset relationship between the outer diameter strain and the life consumption rate to estimate the remaining life of the heat transfer tube. The apparatus for estimating remaining life of heat transfer tubes according to any one of claims 1 to 4 . The outer shape of the heat transfer tube is circular,
The best-fit shape is circular,
The expansion outer shape estimating unit calculates the maximum radial error between the measurement result of the measuring unit and the best-fit shape, and adds the value obtained by multiplying the maximum error by two to the diameter of the best-fit shape. 6. The apparatus for estimating the remaining life of heat transfer tubes according to any one of claims 1 to 5, wherein the expansion outer shape of the heat transfer tubes is estimated. The outer shape of the heat transfer tube is circular,
The best-fit shape is circular,
The expansion outer shape estimating unit calculates an average value and a standard deviation of errors in the radial direction between the measurement result of the measuring unit and the best-fit shape, and is equal to or greater than the value obtained by adding twice the standard deviation to the average value. Any one of claims 1 to 5, wherein the expanded outer shape of the heat transfer tube is estimated by adding to the diameter of the best fit shape a value obtained by doubling the error of the deviation value preset in the range of The remaining life estimating device for the heat transfer tube according to the above item . The outer shape of the heat transfer tube is an oval shape,
The best-fit shape is an oval shape,
The inflated outer shape estimating unit identifies, from among the measurement results obtained by the measuring unit, a measurement point that maximizes the distance from the center point in the best-fit shape, The remaining life estimation device for heat transfer tubes according to any one of claims 1 to 5 , wherein the fit shape is enlarged to estimate the expanded outer shape of the heat transfer tube that is similar to the best fit shape. A shape estimating device for a heat transfer tube provided in a boiler in a power plant, comprising: a measurement unit that partially measures the outer shape of a predetermined side surface of the heat transfer tube; and a circular shape based on the measurement result of the measurement unit or a shape estimating device having a best-fit shape estimating unit that estimates a best-fit shape that is an elliptical shape;
an expanded outer shape estimating unit that estimates an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum based on the result of measurement by the measuring unit and the best-fit shape;
a remaining life estimating unit that estimates the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube;
Remaining life estimation device for heat transfer tubes. A method for estimating the shape of a heat transfer tube provided in a boiler in a power plant,
a measuring step of measuring an outer shape of a partial predetermined side surface of the entire peripheral surface of the heat transfer tube;
Best fit for estimating a best fit shape that is circular or oval for the outer shape of the heat transfer tube including the predetermined side surface and side surfaces other than the predetermined side surface based on the measurement result of the measurement step. a shape estimation step;
an expanded outer shape estimating step of estimating an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum based on the measurement result of the measuring step and the best-fit shape;
a remaining life estimation step of estimating the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube;
A method for estimating the remaining life of a heat transfer tube having In the computer possessed by the remaining life estimation device of the heat transfer tube provided in the boiler in the power plant,
a measurement process of measuring an outer shape of a partial predetermined side surface of the entire peripheral surface of the heat transfer tube;
Best fit for estimating a best fit shape, which is circular or oval, for the outer shape of the heat transfer tube including the predetermined side surface and side surfaces other than the predetermined side surface based on the measurement result of the measurement process. shape estimation processing;
an expanded outer shape estimation process for estimating an expanded outer shape assumed when the heat transfer tube expands substantially to the maximum based on the measurement result of the measurement process and the best-fit shape;
a remaining life estimation process for estimating the remaining life of the heat transfer tube based on the initial outer shape and the expanded outer shape of the heat transfer tube;
program to run the

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