JP5164928B2 - Gas turbine abnormality diagnosis device - Google Patents

Description

  The present invention relates to a gas turbine abnormality diagnosis device.

Gas turbine output (generator output) varies depending on many factors such as compressor inlet temperature, combustor injection steam volume, turbine inlet temperature, turbine outlet temperature, pressure ratio, compression efficiency, etc. To do. In addition, since these factors influence each other, it is difficult to understand abnormalities such as a decrease in output and performance deterioration under normal operating conditions, and the discovery of abnormalities tends to be delayed.
For example, in the gas turbine performance analysis / prediction method of Patent Document 1, a method of analyzing or predicting gas turbine performance from a plurality of original data acquired from an operating gas turbine is disclosed. In this analysis prediction method, one data (for example, gas turbine outlet temperature) serving as an index of gas turbine performance is selected as a target variable from a plurality of original data, and a plurality of data (gas turbine inlet) having a large influence on the target variable is selected. Gas temperature, gas turbine intake temperature, etc.) are selected as explanatory variables. Then, the future performance is predicted by regressing the relationship between the objective variable and the plurality of explanatory variables and analyzing the past performance change from the time series change.

JP 2007-2673 A

However, according to the method of Patent Document 1, it is necessary to collect individual detailed operation data of the compressor, turbine, combustor, and the like, and it is not easy to collect these operation data. Therefore, it cannot be used for early detection of an abnormality occurring in the gas turbine by a simple method. In particular, according to the method of Patent Document 1, a large amount of data is collected, and it is difficult to employ the existing gas turbine.
Therefore, development of an abnormality diagnosis device that can be easily applied to existing turbine equipment has been desired.

  The present invention has been made in view of the above-described conventional problems. A gas turbine capable of easily and quickly performing abnormality diagnosis with a small amount of data collection and easily performing abnormality diagnosis even in an existing gas turbine. An abnormality diagnosis device is intended to be provided.

The present invention includes a compressor that sucks in air, compresses it, and discharges it;
A combustor for combusting compressed air and fuel supplied from the compressor;
An apparatus for diagnosing whether or not any abnormality has occurred in a gas turbine that is disposed on the same axis as the compressor and includes a turbine that is rotated by combustion gas generated in the combustor,
After operating the gas turbine at a predetermined output, in the no-load operation state formed immediately before stopping the operation, the turbine outlet temperature, the compressor inlet temperature, and the turbine inlet temperature Measuring means for measuring at least two of
A first temperature difference obtained by subtracting the compressor inlet temperature from the turbine outlet temperature; a second temperature difference obtained by subtracting the compressor inlet temperature from the turbine inlet temperature; and the turbine inlet temperature. Calculating means for obtaining at least one of the third temperature differences obtained by subtracting the outlet temperature;
When at least one of the first to third temperature differences increases beyond a predetermined normal range, it has an abnormality detecting means for detecting that an abnormality has occurred in the gas turbine. It exists in the abnormality diagnosis apparatus of a gas turbine (Claim 1).

In the gas turbine abnormality diagnosis device of the present invention, in the no-load operation state formed in the gas turbine, the expansion work in the turbine is the sum of the compression work in the compressor and a predetermined friction loss, and the gas turbine is normal. In some cases, the abnormality diagnosis is performed paying attention to the fact that the first to third temperature differences do not change greatly.
In the no-load operation state of the gas turbine, the amount of fuel burned in the combustor is small, and it can be considered that the air compressed by the compressor forms a cycle in which expansion occurs in the turbine.

  The abnormality diagnosis apparatus according to the present invention includes at least two of the turbine outlet temperature, the compressor inlet temperature, and the turbine inlet temperature measured in the no-load operation state by the measuring means, the calculating means, and the abnormality detecting means. And determining at least one of the first to third temperature differences, and when at least one of the first to third temperature differences increases beyond a predetermined normal range, Detects that an abnormality has occurred in the gas turbine. Thereby, in this invention, abnormality diagnosis can be performed by measuring the temperature of each site | part in a gas turbine, and abnormality diagnosis can be performed easily and early by little data collection.

Further, the turbine outlet temperature, the compressor inlet temperature, and the turbine inlet temperature are usually monitored as gas turbine operation data, and the abnormality diagnosis device of the present invention can be easily used in an existing gas turbine. Can be adopted.
The no-load operation state is a state after the gas turbine is operated at a predetermined output. Therefore, the temperature of each part in the gas turbine is stable, and it is possible to suppress the occurrence of errors in abnormality detection.

  Therefore, according to the abnormality diagnosis device for a gas turbine of the present invention, abnormality diagnosis can be performed easily and early with a small amount of data collection, and an abnormality diagnosis can be easily performed even with an existing gas turbine.

Explanatory drawing which shows typically the abnormality diagnosis apparatus of the gas turbine in an Example. The slow chart which shows the flow which performs abnormality diagnosis by the abnormality diagnosis apparatus of the gas turbine in an Example. The graph which shows the state of the change of the temperature difference of each part of the gas turbine at the time of misfire, and the correction | amendment flow volume in a confirmation test. The graph which shows the state of the change of the temperature difference of each part of a gas turbine, and the flow volume after correction | amendment in the confirmation test when turbine dirt generate | occur | produces. The graph which shows the state of the change of the temperature difference of each part of a gas turbine, and the flow volume after correction | amendment when the leak of compressed air generate | occur | produces in a confirmation test.

A preferred embodiment of the above-described gas turbine abnormality diagnosis apparatus of the present invention will be described.
In the present invention, the gas turbine may be configured to have a generator that generates electric power by rotating the turbine. In addition, the combustor may have any configuration in which water vapor is injected or water vapor is not injected.
In the above-described no-load operation state, the generator rotation speed is the rated rotation speed, the generator output is zero, the steam injection amount in the combustor is zero, and the gas turbine is operated after being continuously operated for 1 hour or more. Can be in a state that satisfies all the conditions of stopping.

The measuring means also measures the flow rate of the fuel in the no-load operation state, and the abnormality detecting means has at least one of the first to third temperature differences exceeding a predetermined normal range. When the flow rate increases beyond a predetermined normal range, it can be detected that an abnormality has occurred in the gas turbine.
In this case, the abnormality diagnosis can be performed in consideration of the degree of change in the fuel flow rate, and the abnormality diagnosis can be made more accurate.

Embodiments of a gas turbine abnormality diagnosis apparatus according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the gas turbine 1 of this example includes a compressor 2 that sucks in air A <b> 1 and compresses and discharges it, a combustor 4 that burns compressed air A <b> 2 and fuel F supplied from the compressor 2, and a compressor 2. And a turbine 3 that is rotated by the combustion gas G <b> 1 generated in the combustor 4, and a generator 5 that generates electric power by the rotation of the turbine 3. The abnormality diagnosis device 6 of the gas turbine 1 of this example is configured to receive operation data from a control device that controls the gas turbine 1 and diagnose whether or not any abnormality has occurred in the gas turbine 1.

The abnormality diagnosing device 6 comprises the following measuring means 61, calculating means 62 and abnormality detecting means 63 using a computer.
The measuring means 61 operates the gas turbine 1 at a predetermined output, and in the no-load operation state formed immediately before stopping the operation, the outlet temperature TOT of the turbine 3, the inlet temperature CIT of the compressor 2, and At least two of the inlet temperatures TIT of the turbine 3 are measured. The calculating means 62 also includes a first temperature difference obtained by subtracting the inlet temperature CIT of the compressor 2 from the outlet temperature TOT of the turbine 3, and a second temperature difference obtained by subtracting the inlet temperature CIT of the compressor 2 from the inlet temperature TIT of the turbine 3. And at least one of the third temperature differences obtained by subtracting the outlet temperature TOT of the turbine 3 from the inlet temperature TIT of the turbine 3. The abnormality detection means 63 detects that an abnormality has occurred in the gas turbine 1 when at least one of the first to third temperature differences has increased beyond a predetermined normal range.

Hereinafter, the abnormality diagnosis device 6 for the gas turbine 1 of this example will be described in detail with reference to FIGS. 1 and 2.
As shown in FIG. 1, the gas turbine 1 of this example is a steam injection type gas turbine. In the combustor 4, combustion is performed using fuel F, compressed air A <b> 2, and steam S, and the turbine 3 is generated by the combustion gas G <b> 1. Is configured to generate power by the generator 5 and to generate water vapor S by an exhaust gas steam boiler (not shown) using the exhaust gas G2 from the turbine 3. Steam S is supplied to the combustor 4 from an exhaust gas steam boiler.

The gas turbine 1 of this example is configured to generate power by rotating the generator 5 at a predetermined rated rotational speed (for example, 14000 rpm).
The control device of the gas turbine 1 adjusts the fuel F injection amount and the water vapor S injection amount in the combustor 4 to control the output of the generator 5 to a predetermined output.
The gas turbine 1 is configured to measure the outlet temperature TOT of the turbine 3, the inlet temperature CIT of the compressor 2, the inlet temperature TIT of the turbine 3, and the flow rate of the fuel F. These temperatures and flow rates are all taken into the control device, and the abnormality diagnosis device 6 is configured to receive data on these temperatures and flow rates from the control device.

The abnormality diagnosis device 6 of this example obtains all of the first to third temperature differences, and when any of the first to third temperature differences and the flow rate of the fuel F increase beyond a predetermined normal range. In addition, it is configured to detect that an abnormality has occurred in the gas turbine 1.
The value of the flow rate of the fuel F can be corrected in consideration of a change in the inlet temperature (intake air temperature) CIT in the compressor 2. Specifically, the corrected flow rate Q ′ of the fuel F is obtained from Q ′ = Q × {(273 + Tg) / (273 + CIT)} ^1/2 when the measured value is Q (Nm ³ / hr). Can do. Here, Tg indicates the reference temperature of the air sucked into the compressor 2, and Tg = 15 (° C.).
In the no-load operation state in which abnormality diagnosis is performed by the abnormality diagnosis device 6 of this example, the rotation speed of the generator 5 is the rated rotation speed, the output of the generator 5 is zero, and the amount of steam S injected in the combustor 4 Is zero, and the gas turbine 1 is in a state that satisfies all the conditions that the operation is stopped after continuously operating the gas turbine 1 for one hour or more.

Next, it will be specifically described that abnormality diagnosis can be performed by the abnormality diagnosis device 6 of the present example, and the effects thereof will be described.
Immediately before stopping the gas turbine 1, in the no-load operation state in which the rotational speed of the generator 5 is constant (rated rotational speed), there is no injection of the steam S in the combustor 4, and the injection amount of the fuel F is also the air A1. It is extremely small compared to the amount of intake.
In the no-load operation state formed in the gas turbine 1, when the expansion work in the turbine 3 is Wt, the compression work in the compressor 2 is Wc, and the predetermined friction loss is L, the relationship of Wt = Wc + L is established. Here, Wt is Wt = E × Cpe × (TIT−TOT), and Wc is Wc = A × Cpa × (CDT−CIT). CIT is the inlet temperature of the compressor 2, CDT is the outlet temperature of the compressor 2, TIT is the inlet temperature of the turbine 3, TOT is the outlet temperature of the turbine 3, A is the intake air amount of the compressor 2, and Cpa is the constant pressure of the air A1. Specific heat, E represents the displacement of the turbine 3, and Cpe represents the constant pressure specific heat of the exhaust gas G2.

Below, the error which arises when calculating | requiring the said 1st-3rd temperature difference is examined.
In the gas turbine 1 in the no-load operation state, since the combustion amount in the combustor 4 is small, the intake amount A of the compressor 2 and the exhaust amount E of the turbine 3 are substantially the same. The no-load operation state can be regarded as a cycle in which the air A1 compressed by the compressor 2 expands in the turbine 3, and the constant pressure specific heat Cpe of the exhaust gas G2 is regarded as substantially the same as the constant pressure specific heat Cpa of the air A1. Can do.
Depending on the temperature of the air A1, the intake amount of the compressor 2 slightly changes and the compression work Wc also increases or decreases, but the exhaust amount of the exhaust gas G2 also changes in the same way, and the expansion work Wt increases or decreases. Therefore, the flow of the working gas in the gas turbine 1 only changes, the work performed by the unit intake air amount is the same, and no change as a heat cycle occurs.

In the gas turbine 1 in the no-load operation state, the friction loss L in the gas turbine 1 is substantially constant. Therefore, when the intake air amount of the compressor 2 decreases, the ratio of the friction loss L to the expansion work Wt in the turbine 3 increases, and the inlet temperature TIT of the turbine 3 needs to be increased. However, since the friction loss L is originally very small, there is little influence on obtaining the first to third temperature differences.
Changes in the intake air amount of the compressor 2 change the pressure ratio (expansion ratio), the compression efficiency of the compressor 2, and the expansion efficiency of the turbine 3. As a result, the outlet temperature CDT of the compressor 2, the outlet temperature TOT of the turbine 3, and the like also change. However, in the no-load operation state, the degree of change is minute, and there is little influence on obtaining the first to third temperature differences.

  From the above examination, the thermal cycle in the no-load operation state can be considered only by the temperature change of each part, and draws almost the same temperature cycle based on the inlet temperature CIT of the compressor 2. That is, when the gas turbine 1 is in a normal state, the temperature difference (CDT-CIT), the first temperature difference (TOT-CIT), and the second temperature difference (TIT-CIT) are substantially constant, and these relations To the third temperature difference (TIT-TOT) is also substantially constant. Since the outlet temperature CDT of the compressor 2 is not generally measured, a temperature difference (first to third temperature differences) other than the temperature difference (CDT-CIT) is used as an index when performing abnormality diagnosis.

Further, since the temperature cycle is constant, the flow rate Q ′ of the fuel F corrected for the change in the intake air amount due to the change in the inlet temperature (intake air temperature) CIT of the compressor 2 is taken as the measured value Q (Nm ³ / hr), Q ′ = Q × {(273 + Tg) / (273 + CIT)} ^1/2 . However, since the correction is not always accurate, the value of Q ′ can be supplementarily used when performing abnormality diagnosis.

When an abnormality such as a reduction in efficiency of the compressor 2 or the turbine 3 or an increase in the friction loss L occurs, the combustion amount in the combustor 4 is increased from the relationship of (TIT−TOT) ≈ (CDT−CIT) + L. The operation increases the inlet temperature TIT, and the first temperature difference (TOT-CIT), the second temperature difference (TIT-CIT), the third temperature difference (TIT-TOT), and the corrected flow rate Q ′ of the fuel F Is larger than normal.
On the other hand, when the gas turbine 1 is normal, the first to third temperature differences and the corrected flow rate Q ′ of the fuel F hardly change.

Note that the second temperature difference (TIT-CIT) and the third temperature difference (TIT-TOT) may slightly change each time maintenance is performed. Therefore, by performing abnormality diagnosis mainly using the first temperature difference (TOT-CIT), the diagnosis accuracy of abnormality diagnosis can be increased.
Further, it is considered that the same abnormality diagnosis can be performed even in the no-load operation state when the gas turbine 1 is started. However, since the heat capacity of the main body and piping of the gas turbine 1 is large, the temperature of each part is not stabilized in a short time, and the temperature difference of each part obtained by measurement at the start of the gas turbine 1 is diagnosed abnormally. Cannot be used as an indicator for

FIG. 2 shows a flow of abnormality diagnosis by the abnormality diagnosis device 6 of this example.
The abnormality diagnosis device 6 detects whether or not the output of the generator 5 becomes zero, the injection amount of the water vapor S in the combustor 4 becomes zero, and the gas turbine 1 has been operated continuously for one hour or more (in the drawing). Step S1). When these conditions are satisfied, the measuring means 61 is in the no-load operation state immediately before the operation stop, on condition that the temperature of each part of the gas turbine 1 is stable after 1 hour or more after the operation. Then, the outlet temperature TOT of the turbine 3, the inlet temperature CIT of the compressor 2, the inlet temperature TIT of the turbine 3, and the flow rate of the fuel F are measured (S2).
Next, the calculating means 62 calculates the first temperature difference (TOT-CIT), the second temperature difference (TIT-CIT), the third temperature difference (TIT-TOT), and the corrected flow rate Q ′ of the fuel F. Obtain (S3).

Thereafter, the abnormality detection means 63 indicates that an abnormality has occurred in the gas turbine 1 when any of the first to third temperature differences and the corrected flow rate Q ′ have increased beyond a predetermined normal range (S4). Is detected (S5). On the other hand, when all of the first to third temperature differences are within a predetermined normal range (S4), the abnormality detection means 63 detects that no abnormality has occurred in the gas turbine 1 (S6).
In the abnormality diagnosis (S4), the first temperature difference (TOT-CIT) can be used as a main diagnostic index, and the other can be used as a supplementary diagnostic index. For example, the normal range is set narrow for the first temperature difference (the temperature difference determined to be abnormal is set to a temperature difference close to the normal range), while the normal range is set wide for the other. This can be realized by setting the temperature difference determined to be abnormal to a temperature difference greatly deviating from the normal range.

Thus, in this example, abnormality diagnosis can be performed by measuring the temperature of each part in the gas turbine 1, and abnormality diagnosis can be performed easily and early by collecting a small amount of data. Normally, the outlet temperature TOT of the turbine 3, the inlet temperature CIT of the compressor 2, the inlet temperature TIT of the turbine 3, and the flow rate of the fuel F are monitored as operation data of the gas turbine 1. The diagnostic device 6 can be easily employed in the existing gas turbine 1.
The no-load operation state is a state after the gas turbine 1 is operated at a predetermined output. Therefore, the temperature of each part in gas turbine 1 is stable, and it can control that an error arises in abnormality detection.

  Therefore, according to the abnormality diagnosis device 6 of the gas turbine 1 of this example, the abnormality diagnosis can be performed easily and early by collecting a small amount of data, and the abnormality diagnosis can be easily performed even in the existing gas turbine 1. . In addition, when the operation of the gas turbine 1 is stopped, the presence or absence of an abnormality can be detected, and when there is any abnormality, it can be repaired before the operation is restarted. Further, it is possible to predict the possibility that an abnormality will occur in the gas turbine 1, and it is possible to perform preventive maintenance of the gas turbine 1 by performing maintenance before the abnormality occurs.

(Confirmation test)
In this confirmation test, every time the gas turbine 1 is stopped at intervals of about one week, the abnormality diagnosis device 6 is used to diagnose whether or not an abnormality has occurred in the gas turbine 1.
When an abnormality diagnosis is performed, the first temperature difference (TOT-CIT), the second temperature difference (TIT-CIT), the third temperature difference (TIT-TOT), and the corrected flow rate Q ′ of the fuel F Was used.
FIG. 3 shows the situation when a misfire occurs in one of the plurality of combustors 4 in the gas turbine 1. The horizontal axis indicates time (day), and the vertical axis indicates a temperature difference (° C.) and a flow rate ( Nm ³ / hr), and shows the state of change in each temperature difference and corrected flow rate Q ′. In the figure, it can be seen that the temperature difference and the corrected flow rate Q ′ are increased in the vicinity of 180 days and in the vicinity of 210 days. It can also be seen that the amount of change in the third temperature difference is smaller than the amount of change in other temperature differences.
Therefore, when a misfire occurs in the gas turbine 1, each temperature difference and the corrected flow rate Q ′ increase beyond a predetermined normal range, so that an abnormality has occurred in the gas turbine 1 by the abnormality diagnosis device 6. It can be seen that this can be detected stably.

FIG. 4 shows the situation when the turbine 3 is contaminated in the gas turbine 1 with the horizontal axis representing time (days) and the vertical axis representing temperature difference (° C.) and flow rate (Nm ³ / hr). Each temperature difference and the state of change of the corrected flow rate Q ′ are shown. In the figure, it can be seen that each temperature difference and the corrected flow rate Q ′ repeatedly increase gradually from the vicinity of 60 days. Further, it can be seen that the values of the second temperature difference and the third temperature difference slightly change after maintenance.
As a result, when turbine fouling occurs in the gas turbine 1, each temperature difference and the corrected flow rate Q ′ increase beyond a predetermined normal range, so that abnormality diagnosis is performed mainly with the first temperature difference as the main. By doing so, it can be seen that the occurrence of any abnormality in the gas turbine 1 can be detected stably.

FIG. 5 shows the situation when compressed air A2 leaks in the gas turbine 1, with the horizontal axis representing time (days) and the vertical axis representing temperature difference (° C.) and flow rate (Nm ³ / hr). Each temperature difference and the state of change of the corrected flow rate Q ′ are shown. In the figure, it can be seen that the first to third temperature differences and the corrected flow rate Q ′ increase in the vicinity of 60 days.
As a result, when the compressed air A2 leaks in the gas turbine 1, each temperature difference and the corrected flow rate Q ′ increase beyond a predetermined normal range, so that some abnormality has occurred in the gas turbine 1. It can be seen that can be detected stably. In addition, the case of FIG. 5 is the result of having performed the confirmation test about the thing in which the model of the gas turbine 1 differs from the case of FIG. 3, FIG.

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 3 Turbine 4 Combustor 5 Generator 6 Abnormality diagnosis apparatus 61 Measuring means 62 Calculation means 63 Abnormality detection means A1 Air A2 Compressed air F Fuel G1 Combustion gas G2 Exhaust gas CIT Compressor inlet temperature CDT Compressor outlet temperature TIT Turbine inlet temperature TOT Turbine outlet temperature

Claims (2)

A compressor that draws in air, compresses it, and discharges it;
A combustor for combusting compressed air and fuel supplied from the compressor;
An apparatus for diagnosing whether or not any abnormality has occurred in a gas turbine that is disposed on the same axis as the compressor and includes a turbine that is rotated by combustion gas generated in the combustor,
After operating the gas turbine at a predetermined output, in the no-load operation state formed immediately before stopping the operation, the turbine outlet temperature, the compressor inlet temperature, and the turbine inlet temperature Measuring means for measuring at least two of
A first temperature difference obtained by subtracting the compressor inlet temperature from the turbine outlet temperature; a second temperature difference obtained by subtracting the compressor inlet temperature from the turbine inlet temperature; and the turbine inlet temperature. Calculating means for obtaining at least one of the third temperature differences obtained by subtracting the outlet temperature;
When at least one of the first to third temperature differences increases beyond a predetermined normal range, it has an abnormality detecting means for detecting that an abnormality has occurred in the gas turbine. Gas turbine abnormality diagnosis device. In claim 1, the measuring means also measures the flow rate of the fuel in the no-load operation state,
The abnormality detecting means is configured to detect the gas when at least one of the first to third temperature differences increases beyond a predetermined normal range and the flow rate also increases beyond a predetermined normal range. An abnormality diagnosis device for a gas turbine, characterized by detecting that an abnormality has occurred in a turbine.

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