JP5302264B2 - High temperature component life diagnosis method and diagnostic device - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for diagnosing the life of a high-temperature component, and in particular, diagnosing the life of a high-temperature component based on a gas turbine exhaust gas temperature suitable for use in a combined cycle power plant having a gas turbine and an exhaust heat recovery boiler using exhaust gas from the gas turbine. The present invention relates to a method and a diagnostic apparatus.

  In the gas turbine, it is important to manage the life of a high-temperature part that is exposed to a high temperature of 1300 ° C., and the high-temperature part is regularly replaced to maintain stable operation and maintain performance.

  In general, with regard to the life of gas turbine high-temperature components, the remaining life is evaluated by calculating the life consumption rate in consideration of the operation time of the gas turbine and the unsteady operation such as the number of start-ups and the number of trips.

  In addition, what removes the steady deviation of gas turbine outlet temperature using the outlet temperature of a gas turbine and temperature downstream from this is known (for example, refer patent document 1).

JP-A-6-264761

  However, even under the same operating conditions, the damage status of high-temperature parts varies depending on the plant. What is going on is the reality.

  In addition, when the gas turbine high-temperature components deteriorate over time, the output and efficiency of the gas turbine and the plant decrease, and in some cases, the specified output cannot be output, or the operation may be hindered due to the decrease in efficiency. Regarding performance degradation due to degradation of this high-temperature component, it can be seen that the performance is degraded by monitoring the operation data, but it is very difficult to understand what caused the performance degradation during operation. It is difficult to implement performance recovery measures during operation.

  Therefore, damaged high-temperature parts can be confirmed for the first time by disassembling and inspecting the gas turbine during periodic inspections, and performance can be restored by repairing and replacing those parts.

  For this reason, if the required output cannot be achieved, it is forced to operate without reaching the output until the next regular inspection, which will hinder the operation.

  For high-temperature parts, a replacement schedule for each part is determined based on a long-term schedule, and parts are prepared and replaced / repaired according to the replacement period. And repairs may be carried out.

  As a result, unexpected parts may be damaged, which may increase the number of regular inspection days by preparing parts quickly, or the parts that were planned for replacement may not have been damaged much. Although it is important to accurately grasp the life of gas turbine hot parts, it is actually very difficult.

  As described above, the life of high-temperature parts of the gas turbine is not simply assumed from the inspection results at the time of overhaul, but if the damage status of the parts can be confirmed during operation, it will be easily reflected in the previous inspection plan, and It is also very useful for reflection in a typical inspection plan.

  In addition, when sudden damage is expected, it is possible to plan the parts preparation and inspection as soon as possible, so that damage to the plant operation can be minimized.

  Therefore, it is very important to check the damage status of high-temperature parts during plant operation.

  An object of the present invention is to provide a life diagnosis method and a diagnosis apparatus for a high temperature component capable of grasping a damage state of a gas turbine high temperature component and capable of performing a life diagnosis of the high temperature component.

(1) In order to achieve the above object, the present invention is used in a combined cycle power plant having a gas turbine and an exhaust heat recovery boiler that uses exhaust gas from the gas turbine. A method for diagnosing the life of a high-temperature component, wherein the exhaust gas temperature of the gas turbine is measured at the outlet side of the gas turbine and the inlet side of the exhaust heat recovery boiler, and the plant control controls the operation of the gas turbine The apparatus uses the relationship between the temperature difference stored in advance in the database and the damage level of the high-temperature component due to the change in the temperature difference between the measured gas turbine outlet temperature and the exhaust heat recovery boiler inlet temperature. It is designed to predict and diagnose aged deterioration of a gas turbine.
With this method, it is possible to grasp the damage state of the gas turbine high-temperature component, and it is possible to diagnose the life of the high-temperature component.

  (2) In the above (1), preferably, the plant control device uses the relationship between the temperature difference accumulated in advance in the database and the damage level of the high temperature component to determine the replacement timing of the high temperature component of the gas turbine. It is something to be predicted.

  (3) In the above (1), preferably, the plant control device prompts a change of the operation mode when the speed of damage is faster than expected and there is a possibility of causing a performance degradation more than expected by the regular inspection. It is what I did.

  (4) In the above (1), preferably, the plant control device uses an exhaust gas temperature control line set by a compressor outlet pressure and an exhaust gas temperature so that the combustion temperature becomes constant. The exhaust gas temperature on the outlet side is controlled to coincide with the exhaust gas temperature control line.

(5) Moreover, in order to achieve the said objective, this invention combined with a gas turbine, the waste heat recovery boiler using the exhaust gas of this gas turbine, and the plant control apparatus which controls the driving | operation of the said gas turbine. A high-temperature component life diagnosis device used in a cycle power plant for diagnosing the life of a high-temperature component of the gas turbine, wherein the temperature measurement measures the temperature at the outlet side of the gas turbine and the inlet side of the exhaust heat recovery boiler Means, and a database in which the relationship between the temperature difference between the outlet side temperature of the gas turbine and the inlet side temperature of the exhaust heat recovery boiler and the damage level of the high temperature component is stored, and the plant control device is measured The temperature difference accumulated in the database and damage to high-temperature parts due to the temperature difference between the gas turbine outlet temperature and the exhaust heat recovery boiler inlet temperature. Using the relationship between the bell, in which the aging of the gas turbine and adapted to prognosticating.
With this configuration, it is possible to grasp the damage status of the gas turbine high-temperature component, and it is possible to diagnose the life of the high-temperature component.

ADVANTAGE OF THE INVENTION According to this invention, the damage condition of gas turbine high temperature components can be grasped | ascertained, and the lifetime diagnosis of high temperature components is attained.

1 is a system configuration diagram of a single-shaft combined plant power generation facility using a high-temperature component life diagnosis apparatus according to an embodiment of the present invention. It is explanatory drawing of the time-dependent change of gas turbine exhaust gas temperature T1, exhaust heat recovery boiler inlet temperature T2, and its temperature difference (DELTA) T used for the lifetime diagnostic apparatus of the high temperature components by one Embodiment of this invention. It is explanatory drawing of the exhaust temperature control line for demonstrating the diagnostic principle in the lifetime diagnostic apparatus of the high temperature components by one Embodiment of this invention. It is explanatory drawing of the diagnostic method by the lifetime diagnostic apparatus of the high temperature components by one Embodiment of this invention. It is explanatory drawing of the diagnostic method by the lifetime diagnostic apparatus of the high temperature components by one Embodiment of this invention.

Hereinafter, the configuration and operation of a high-temperature component life diagnosis apparatus according to an embodiment of the present invention will be described with reference to FIGS.
First, a system configuration of a single-shaft combined plant power generation facility that uses the high-temperature component life diagnosis apparatus according to the present embodiment will be described with reference to FIG.
FIG. 1 is a system configuration diagram of a single-shaft combined plant power generation facility using a high-temperature component life diagnosis apparatus according to an embodiment of the present invention.

  The air compressor 1, the gas turbine 3, the generator 4, and the steam turbine 5 are connected to one shaft. The air taken into the air compressor 1 is compressed and supplied to the combustor 2. In the combustor 2, the supplied fuel is burned together with the compressed air. The combustion gas is supplied to the gas turbine 3 and drives the gas turbine 3. The exhaust heat of the gas turbine 3 is taken into the exhaust heat recovery boiler 6. The exhaust heat recovery boiler 6 guides the exhaust gas of the gas turbine 3 to recover the exhaust heat, and releases the gas after the exhaust heat recovery to the atmosphere. Water is supplied to the exhaust heat recovery boiler 6 by a feed water pump 8. The supplied water becomes steam by exhaust heat and is supplied to the steam turbine 5. The steam turbine 5 is driven by steam supplied through the exhaust heat recovery boiler 6. The condenser 7 condenses the exhaust from the steam turbine 5 and supplies the condensed water to the exhaust heat recovery boiler 6 with the feed water pump 8. The shaft is rotated by the gas turbine 3 and the steam turbine 5 to drive the generator 4.

  The measured numerical values of the thermometer 10 installed in the vicinity of the gas turbine outlet and the thermometer 11 installed in the vicinity of the exhaust heat recovery boiler inlet are taken into the arithmetic control device 41 which is a plant performance monitoring device. The arithmetic and control unit 41 stores damage data.

  The arithmetic and control unit 41 continuously captures and monitors the temperature difference ΔT from the measured gas turbine exhaust gas temperature T1 and the exhaust heat recovery boiler inlet temperature T2 in an operation state with a constant base load.

  Moreover, the arithmetic and control unit 41 accumulates in the database 42 the damage status of the gas turbine high temperature components at the time of regular inspection of the present plant and various other plants, and continuously manages them. In the database 42, for example, the damage at the tip of the turbine rotor blade, the damage amount of the shroud, etc. are digitized, and the relationship between the temperature difference between the gas turbine exhaust gas temperature and the exhaust heat recovery boiler inlet temperature is accumulated.

Next, changes with time of the gas turbine exhaust gas temperature T1, the exhaust heat recovery boiler inlet temperature T2, and the temperature difference ΔT used in the high-temperature component life diagnosis apparatus according to the present embodiment will be described with reference to FIG.
FIG. 2 is an explanatory diagram of changes with time of the gas turbine exhaust gas temperature T1, the exhaust heat recovery boiler inlet temperature T2, and the temperature difference ΔT used in the high-temperature component life diagnosis apparatus according to one embodiment of the present invention.

  FIG. 2 shows changes over time in the gas turbine exhaust gas temperature T1, the exhaust heat recovery boiler inlet temperature T2, and the temperature difference ΔT thereof.

  Although the gas turbine exhaust gas temperature T1 varies depending on the season, there is no yearly change in the same season. On the other hand, the exhaust heat recovery boiler inlet temperature T2 is gradually decreased with time in addition to seasonal fluctuations.

  At this time, the temperature difference ΔT gradually increases, and returns to the initial state when the high temperature parts are largely replaced in the regular inspection.

Next, with reference to FIG. 3, the diagnosis principle of the high temperature component life diagnosis apparatus according to the present embodiment will be described.
FIG. 3 is an explanatory diagram of an exhaust temperature control line for explaining the diagnostic principle in the high-temperature component life diagnostic apparatus according to one embodiment of the present invention.

  In FIG. 3, the horizontal axis indicates the outlet pressure of the air compressor, and the vertical axis indicates the combustion temperature.

  In general, a gas turbine is controlled and operated so that the combustion temperature is constant for the purpose of operating at a combustion temperature lower than the design-acceptable combustion temperature and operating with high efficiency. However, since the combustion temperature cannot be directly measured, the combustion temperature is actually controlled by the exhaust temperature control line set by the compressor outlet pressure and the exhaust temperature shown in FIG.

  The exhaust gas temperature at the gas turbine outlet changes due to aged deterioration associated with the operation time of the gas turbine and the like. In actual operation, even if this temperature change occurs, the combustion temperature is controlled by feeding back the exhaust temperature of the gas turbine so that it matches the exhaust temperature control line. However, since the performance of the gas turbine is reduced accordingly, it is necessary to accurately grasp the gas turbine exhaust gas temperature and predict aging degradation.

  In a combined cycle power plant having an exhaust heat recovery boiler, the exhaust gas temperature is also measured on the exhaust heat recovery boiler side. Since the temperature of the exhaust heat recovery boiler outlet is far from the gas turbine outlet, the temperature is made uniform in the duct as compared with the gas turbine outlet.

  At this time, when the exhaust gas temperature at the gas turbine outlet and the exhaust gas temperature at the exhaust heat recovery boiler inlet are compared, it has been confirmed that the temperature difference changes over time. This is because, as described above, the exhaust gas temperature at the gas turbine outlet is fed back and the fuel flow rate is controlled so as to become a predetermined value, so that the exhaust gas temperature of the gas turbine does not change apparently.

  However, in actuality, the exhaust gas temperature has a temperature distribution in the radial direction, and the temperature distribution changes due to damage to high-temperature parts, etc., so the exhaust gas temperature measured at a certain position is the same fuel consumption. Change.

  When the exhaust gas temperature at the measurement position becomes high due to damage of high-temperature parts or the like, the fuel consumption is suppressed as a result, and the performance of the gas turbine is reduced. At this time, since the amount of fuel input is decreasing, the amount of heat to the exhaust heat recovery boiler is decreased, so that the temperature of the uniform exhaust heat recovery boiler inlet is decreased. The temperature difference that occurs here is due to the blade tip that is a gas turbine high-temperature component thinning due to high temperature, or the part called the shroud on the casing side being scraped over time or thinning due to high temperature, resulting in damage to the blade tip The increase in the gap on the casing side reduces the work of the turbine, and the exhaust gas is caused to flow downstream at a high temperature.

  Since this damage state can be confirmed at the time of overhaul inspection at the regular inspection, the damage state of the high temperature component can be predicted by grasping the temperature difference by associating the temperature difference and the damage state of the high temperature component in a database.

  In this embodiment, paying attention to this temperature difference and continuously measuring it, it is possible to diagnose the high-temperature component life of the gas turbine by calculating aged deterioration against a database of damage status of the component.

Next, a diagnosis method using the high-temperature component life diagnosis apparatus according to the present embodiment will be described with reference to FIGS. 4 and 5.
4 and 5 are explanatory diagrams of a diagnosis method using a high-temperature component life diagnosis apparatus according to an embodiment of the present invention.

  FIG. 4 shows the stored contents of the database 42 provided in the arithmetic and control unit 41 which is a plant performance monitoring device. As the database, the temperature difference and the damage level of the high-temperature parts are classified as shown in FIG. For example, if the temperature difference is equal to or less than Δt1, the high-temperature parts can be continuously used without significantly affecting the performance. When the temperature difference is between Δt1 and ΔT2, the performance is affected but is still slight, and high temperature parts can be reused by repair. If the temperature difference is equal to or greater than ΔT2, the repair is not effective even for high-temperature parts, and the performance is greatly affected.

  FIG. 5 shows the passage of time of the temperature difference ΔT between the gas turbine exhaust gas temperature T1 and the exhaust heat recovery boiler inlet temperature T2 taken into the arithmetic and control unit 41 which is a plant performance monitoring device. The solid line indicates the actually measured temperature difference ΔT, and the broken line indicates the predicted value predicted from the actual measurement value.

  The arithmetic and control unit 41 monitors the temperature difference ΔT of the target plant every moment and compares it with the temperature difference in the database 42. For example, when the temperature difference becomes ΔT1 at time t1, although it affects the performance, it is still minor and the high-temperature parts can be reused by repairing, so it is determined that repair is necessary. Further, if a change in the temperature difference is estimated from a measured value of the temperature difference so far as indicated by a dotted line and it can be predicted that the temperature difference ΔT2 will be reached at time t2, it can be determined that repair is necessary before that. Further, by making a prediction at a time before time t1, it is determined that repair is necessary before time t2 after time t1. In this way, by confirming the tendency, it is possible to predict the damage situation until the next regular inspection.

  Thus, in some cases, if there is a part that needs to be replaced earlier than planned, it is possible to prepare in advance, so that it is possible to avoid a process delay corresponding to the occurrence of damage at the time of regular inspection.

  In addition, if it is found that the damage speed may be faster than expected and there is a possibility that the performance may be degraded more than expected by the regular inspection, change the operation mode by increasing the inspection time or reducing the operation load, etc. It is possible to prevent damage to the main body from spreading to other parts by taking measures such as carrying out operations with less burden on the parts in advance. For this purpose, the arithmetic and control unit 41 prompts to change the operation mode. As a combined cycle power plant, when operating a single gas turbine, an example of changing the operation mode is to reduce the operating load of the gas turbine. For example, multiple gas turbines are operated in parallel. In this case, the operation mode is changed so that the overall load becomes the same by lowering the operation load of the gas turbine that may cause the performance degradation and increasing the operation load of other gas turbines. It can also be.

  In addition, if you have a long-term maintenance service contract with the customer and the administrator is monitoring this data, you can predict damage in advance, so you can recommend replacement parts to the customer and advance the regular inspection. Can make a suggestion.

It should be noted that the types and forms, types, configurations, combinations, and capacity of the power generation facilities described in the above-described embodiments limit the scope of the present invention unless otherwise specified. It is not a gist but merely an illustrative example.

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Combustor 3 ... Gas turbine 4 ... Generator 5 ... Steam turbine 6 ... Exhaust heat recovery boiler 7 ... Condenser 8 ... Feed water pump 10, 11 ... Thermometer 41 ... Plant controller 42 ... Database

Claims (5)

Used in a combined cycle power plant having a gas turbine and an exhaust heat recovery boiler that uses exhaust gas from the gas turbine,
A method for diagnosing the lifetime of a high-temperature component of the gas turbine,
Measuring the exhaust gas temperature of the gas turbine at the outlet side of the gas turbine and the inlet side of the exhaust heat recovery boiler;
The plant control device for controlling the operation of the gas turbine is configured so that the temperature difference stored in the database in advance and the high-temperature component are changed according to the change in the temperature difference between the measured outlet temperature of the gas turbine and the inlet temperature of the exhaust heat recovery boiler. A method for diagnosing the lifetime of a high-temperature component, wherein the age-related deterioration of the gas turbine is predicted and diagnosed using a relationship with a damage level. In the high temperature component life diagnosis method according to claim 1,
The plant control device predicts the replacement time of the high-temperature component of the gas turbine using the relationship between the temperature difference accumulated in the database in advance and the damage level of the high-temperature component. Method. In the high temperature component life diagnosis method according to claim 1,
The plant control apparatus prompts a change in the operation mode when the damage speed is faster than expected and there is a possibility that the performance may be deteriorated more than expected before a regular inspection. In the high temperature component life diagnosis method according to claim 1,
The plant control device uses an exhaust gas temperature control line set by a compressor outlet pressure and an exhaust gas temperature so that the combustion temperature is constant, and the exhaust gas temperature on the outlet side of the gas turbine is changed to the exhaust gas temperature control line. A method for diagnosing the life of a high-temperature component, characterized in that the control is performed so as to match. Used in a combined cycle power plant having a gas turbine, an exhaust heat recovery boiler that uses exhaust gas from the gas turbine, and a plant controller that controls the operation of the gas turbine,
A life diagnosis device for high temperature parts for diagnosing the life of high temperature parts of the gas turbine,
Temperature measuring means for measuring temperatures on the outlet side of the gas turbine and the inlet side of the exhaust heat recovery boiler;
A database storing the relationship between the temperature difference between the outlet side temperature of the gas turbine and the inlet side temperature of the exhaust heat recovery boiler and the damage level of the high-temperature components;
The plant control device uses a relationship between a temperature difference accumulated in advance in a database and a damage level of a high-temperature component due to a change in temperature difference between the measured outlet temperature of the gas turbine and the inlet side temperature of the exhaust heat recovery boiler. A life diagnosis apparatus for high-temperature parts, characterized by predicting and diagnosing aged deterioration of the gas turbine.

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