JP5843515B2 - Gas turbine, gas turbine control device, and power generation system - Google Patents

Description

  The present invention relates to a gas turbine, a gas turbine control device, and a power generation system.

  Conventionally, for example, a method disclosed in Patent Document 1 is known as a technique related to control and operation of a gas turbine. In Patent Document 1, in a gas turbine having a bypass flow path for bypassing the combustor and supplying compressed air from the compressor to the turbine, when the increase in output is required, the bypass flow path is set from the compressor. Adjust the fuel supplied to the combustor so that the amount of bleed gas supplied to the turbine via the maximum is reached and the gas turbine inlet temperature at that time does not exceed the preset maximum value of the gas turbine inlet temperature. Is disclosed.

JP 2010-261458 A

  Incidentally, as disclosed in the above-mentioned Patent Document 1, in a gas turbine having a bypass channel that bypasses the combustor and supplies compressed air from the compressor to the turbine, the flow rate of air flowing through the bypass channel varies. As a result, the turbine inlet temperature of the gas turbine changes. As a result, for example, when the bypass air flow rate decreases, the ratio of the fuel amount to the combustion air relatively decreases compared to the reference bypass air flow rate, so the thermal efficiency decreases due to the turbine inlet temperature decrease. To do. On the other hand, when the bypass air flow rate increases, the ratio of the fuel amount to the combustion air increases relatively compared to the reference bypass air flow rate, resulting in excessive fuel, and the turbine inlet temperature becomes unnecessarily high. Rise and cause overfire.

  The present invention has been made in view of such circumstances, and in a gas turbine having a bypass passage that bypasses the combustor and supplies compressed air from the compressor to the turbine, the bypass passage is provided. An object of the present invention is to provide a gas turbine, a gas turbine control device, and a power generation system that can reflect the flow rate of air supplied to the turbine in operation.

In order to solve the above problems, the present invention employs the following means.
The present invention includes a compressor, a combustor, a gas turbine comprising a turbine, is connected from the compressor to the turbine, the air compressed by said compressor, bypassing the combustor A bypass flow path that is supplied as cooling air for cooling the turbine , a flow rate adjusting means that is provided in the bypass flow path for adjusting the flow rate of air flowing through the bypass flow path, and keeps the inlet temperature of the turbine constant. used for the first information indicating a relationship of parameters related to the inlet temperature of the turbine, and correcting means for correcting the first information on the basis of parameters related to the air flow rate or air flow rate flowing through the bypass passage , when the first information is corrected by said correction means, wherein whether the inlet temperature of the turbine is constant using the first information after the correction To provide a gas turbine having a determination means.

  According to the present invention, the bypass flow path for supplying a part of the air compressed by the compressor to the turbine by bypassing the combustor is provided, and the flow rate of air bypassed by the flow rate adjusting means can be adjusted. ing. In addition, first information used to maintain a constant inlet temperature of the turbine and indicating a parameter relationship related to the inlet temperature of the turbine is prepared in advance. The first information is corrected based on the parameter relating to the flow rate. When the first information is corrected by the correcting means, the determining means determines whether or not the inlet temperature of the turbine is constant based on the corrected first information. Thus, since the first information is corrected based on the air flow rate flowing through the bypass flow path, whether or not the inlet temperature of the turbine is constant based on appropriate first information corresponding to the bypassed air flow rate. Can be determined.

  The gas turbine adjusts the amount of fuel supplied to the combustor based on a flow rate of air flowing through the bypass passage or a parameter relating to the flow rate of air when it is determined that the inlet temperature of the turbine is not constant. Means may be provided.

  According to such a configuration, when it is determined that the inlet temperature of the turbine is not constant, the amount of fuel supplied to the combustor is adjusted based on the air flow rate of the bypass passage or the parameter relating to the air flow rate. . As a result, the amount of fuel supplied to the combustor is adjusted in a direction that makes the turbine inlet temperature constant, so that the turbine inlet temperature can be kept constant.

  In the gas turbine, the flow rate adjusting means may be a valve, and an air flow rate flowing through the bypass flow path may be estimated based on a valve opening degree of the valve and a differential pressure before and after the valve.

  According to such a configuration, the flow rate of air flowing through the bypass channel is estimated from the opening degree of the valve provided as the flow rate adjusting means and the differential pressure before and after the valve.

  In the gas turbine, the correction unit uses the value obtained by dividing the difference between the air flow rate flowing through the bypass flow path and a preset reference air flow rate by the air flow rate at the compressor inlet, to obtain the first information. It is good also as correcting.

  According to such a configuration, the first information is corrected based on the ratio of the difference between the air flow rate flowing through the bypass flow path and the reference air flow rate to the air flow rate at the compressor inlet, and thus more appropriate first information. Can be obtained.

  In the gas turbine, the first information is a temperature control characteristic that associates a casing pressure and an exhaust gas temperature on the downstream side of the final stage of the turbine, and the determination means includes the casing pressure and the exhaust gas temperature. When the above relationship deviates from the temperature control characteristic beyond a predetermined allowable range, it may be determined that the inlet temperature of the turbine is not constant.

  According to such a configuration, the first information is a temperature control characteristic that relates the cabin pressure and the exhaust gas temperature, and the measured value of the cabin pressure and the measured value of the exhaust gas temperature are obtained from the temperature control characteristic. If the predetermined allowable range is exceeded, it is determined that the turbine inlet temperature is not constant.

  In the gas turbine, the correction unit may correct the first information when the valve opening degree of the valve changes.

  According to such a configuration, when the valve opening degree of the valve changes, the correction of the first information is performed by the correction unit, and thus the processing can be reduced.

  The present invention provides a power generation system comprising any one of the gas turbines described above and a generator that generates electric power from the gas turbine.

The present invention includes a compressor, a combustor, a turbine, is connected from the compressor to the turbine, the air compressed by the compressor, as cooling air for cooling the turbine bypasses the combustor A gas turbine control device for controlling a gas turbine, comprising a bypass flow path to be supplied and a flow rate adjusting means for adjusting a flow rate of air flowing in the bypass flow path and adjusting the flow rate of the turbine. It used to keep the inlet temperature constant, the first information indicating a relationship of parameters related to the inlet temperature of the turbine, the first information on the basis of parameters related to the air flow rate or air flow rate flowing through the bypass passage and correcting means for correcting, when the first information is corrected by said correction means, using said first information corrected turbine Inlet temperature to provide a gas turbine control apparatus comprising determining means for determining whether a constant.

  According to the present invention, the flow rate of air supplied to the turbine via the bypass flow path can be reflected in the operation, and an effect that a more stable operation can be realized is achieved.

It is the figure which showed schematic structure of the electric power generation system which concerns on one Embodiment of this invention. It is the functional block diagram which expanded and showed the function with which the gas turbine control device concerning one embodiment of the present invention is provided. It is the figure which showed an example of the temperature control characteristic. It is the functional block diagram which expanded and showed the function with which the correction | amendment part shown in FIG. 2 is provided. It is a figure for demonstrating how to obtain | require a correction amount. It is the flowchart which showed the procedure of the process performed by the temperature control part with which a gas turbine control apparatus is provided.

Hereinafter, an embodiment of a gas turbine, a gas turbine control device, and a power generation system according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a power generation system according to an embodiment of the present invention. As shown in FIG. 1, the power generation system includes a gas turbine 10 and a generator 20. The gas turbine 10 includes a compressor 11 that compresses air, a combustor 12 that injects and burns fuel into the compressed air sent from the compressor 11, and generates high-temperature combustion gas, and the combustor 12. A turbine 13 driven by the high-temperature combustion gas exiting the combustor 12 and a gas turbine control device 14 for controlling the amount of fuel supplied to the combustor 12 are provided as main components. Yes.

  The generator 20 is connected to the same rotating shaft as the turbine 13, and generates power when the rotation of the turbine 13 is transmitted. The compressor 11 is also connected to the rotating shaft of the turbine 13 and is driven by the rotation of the turbine 13. The compressor 11, the combustor 12, and the turbine 13 are accommodated in a gas turbine casing (not shown).

  The combustion gas that has worked in the turbine 13 is discharged through an exhaust line. The intake amount of the compressor 11 is adjusted by opening and closing an inlet guide vane (IGV: Inlet Guide Vane) 15 provided at the inlet of the compressor 11. Control of the inlet guide vanes 15 is performed by the gas turbine controller 14.

  The gas turbine 10 includes a bypass passage 16 that bypasses the combustor 12 and supplies compressed air from the compressor 11 to the gas turbine 13. For example, the bypass flow path 16 is a flow path that guides compressed air extracted from the middle of the compressor 11 to the inside of a turbine vane that constitutes the turbine 13.

In the present embodiment, for convenience of explanation, it is assumed that one bypass flow path 16 is provided. For example, the bypass flow path 16 uses compressed air extracted from the low pressure stage of the compressor 11 as a turbine 13. A bypass flow path that leads to the inside of the low pressure stage stationary blade, a bypass flow path that guides the compressed air extracted from the intermediate pressure stage of the compressor 11 to the inside of the intermediate pressure stage stationary blade of the turbine 13, and the compressor 11 A plurality of flow paths such as a bypass flow path for guiding the compressed air extracted from the high pressure stage to the inside of the stationary blades of the high pressure stage of the turbine 13 may be provided. Further, the number of the flow paths is not limited.
The extracted compressed air introduced into the turbine stationary blade is used as purge air for cooling the turbine disk or turbine for the purpose of preventing the strength of the turbine disk (not shown) on which the turbine rotor blades are arranged. Used for sealing between discs (disc cavities).

The bypass passage 16 is provided with a bypass valve (flow rate adjusting means) 18 for controlling the extraction flow rate supplied to the turbine 13. The valve opening degree of the bypass valve is controlled by the gas turbine control device 14.
For example, the gas turbine control device 14 measures the temperature of the disk cavity, and when the temperature becomes higher than the limit value, the opening degree of the bypass valve 18 is increased in order to maintain the strength of the turbine disk. As a result, the purge air in the disk cavity is increased, and the temperature of the disk cavity is controlled to decrease. Further, when there is a margin between the temperature of the disk cavity and the limit value, the gas turbine control device 14 reduces the opening of the bypass valve 18 to improve the thermal efficiency of the gas turbine 10 and reduces the compressed air to be extracted. cut back.

  A fuel supply path 25 for supplying fuel is connected to the combustor 12. A flow rate adjustment valve 26 is provided in the fuel supply path 25. The amount of fuel gas supplied to the combustor 12 is controlled by controlling the opening degree of the flow control valve 26 by the gas turbine control device 14.

The gas turbine control device 14 is, for example, a computer, and includes a main storage device such as a CPU (Central Processing Unit) and a RAM (Random Access Memory), an auxiliary storage device, a communication device, and the like.
The auxiliary storage device is a computer-readable recording medium, such as a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, or a semiconductor memory. The auxiliary storage device stores various programs (for example, a fuel flow rate determination program, a temperature control program, etc.), and the CPU reads out the program from the auxiliary storage device to the main storage device, and executes various processes. Is realized.

  FIG. 2 is a functional block diagram showing the functions provided in the gas turbine control device 14 in an expanded manner. As shown in FIG. 2, the gas turbine control device 14 includes a fuel flow rate determination unit 30, a temperature control unit 31, and a fuel valve opening determination unit 32.

  The fuel flow rate determination unit 30 determines the fuel flow rate based on various parameters such as a target power generation command value and a gas turbine output, for example. For example, a load control signal LDCSO, a governor control signal GVCSO, a blade path temperature control signal BPCSO, and an exhaust gas control signal EXCSO calculated by various control units (not shown) are input to the fuel flow rate determination unit 30.

The load control signal LDCSO is a control signal for controlling the fuel flow rate so that the generator output matches the generator output command, and the governor control signal GVCSO matches the rotational speed or the rotational speed of the turbine 13 with the target value. The blade path temperature control signal BPCSO is a control signal for controlling the fuel flow rate so that the blade path temperature BPT of the turbine 13 does not exceed the blade path temperature upper limit value. The exhaust gas control signal EXCSO is a control signal for controlling the fuel flow rate so that the exhaust gas temperature does not exceed the exhaust gas temperature upper limit value. Here, the exhaust gas temperature means the temperature of the exhaust gas on the downstream side of the final stage of the turbine. The fuel flow rate determination unit 30 selects a control signal having the lowest value from the various control signals that have been input, and outputs this as a fuel flow rate command CSO.
The method for determining the fuel flow rate command CSO based on each control signal described above is a known technique, and for example, a method disclosed in Japanese Patent Application Laid-Open No. 2007-711144 can be used.

The temperature control unit 31 includes a storage unit 40, a correction unit (correction unit) 41, a determination unit (determination unit) 42, and a fuel adjustment unit (fuel adjustment unit) 43 as main components.
The storage unit 40 stores first information that is used to keep the inlet temperature of the turbine 13 constant and that indicates the relationship of parameters related to the temperature of the turbine 13. As the first information, for example, there is a temperature control characteristic in which the cabin pressure and the exhaust gas temperature are associated with each other. FIG. 3 is a diagram illustrating an example of temperature control characteristics. In the temperature control characteristics shown in FIG. 3, the horizontal axis represents the gas turbine casing pressure, and the vertical axis represents the exhaust gas temperature. Here, instead of the gas turbine casing pressure, the compressor outlet pressure may be used.

  The correction unit 41 corrects the temperature control characteristic stored in the storage unit 40 based on the flow rate of air flowing through the bypass flow path 16 and updates the temperature control characteristic in the storage unit 40. Details of the correction unit 41 will be described later.

  The determination unit 42 determines whether or not the inlet temperature of the turbine 13 is kept constant using the temperature control characteristics stored in the storage unit 40. Specifically, when the measured values of the gas turbine casing pressure and the exhaust gas temperature deviate from the temperature control characteristics stored in the storage unit 40 beyond a predetermined allowable range, the inlet temperature of the turbine 13 is constant. It is determined that it is not. Here, the allowable range can be arbitrarily set by design.

The fuel adjustment unit 43 adjusts the fuel flow rate command CSO determined by the fuel flow rate determination unit 30 when the determination unit 42 determines that the inlet temperature of the turbine 13 is not constant.
Specifically, in the temperature control characteristic shown in FIG. 3, when the point determined by the measured value of the gas turbine casing pressure and the measured value of the exhaust gas temperature is located below the temperature control characteristic, Then, it is determined that the fuel is insufficient, and the fuel flow rate command CSO is increased by a predetermined amount. On the other hand, in the temperature control characteristic shown in FIG. 3, when the point determined by the measured value of the gas turbine casing pressure and the measured value of the exhaust gas temperature is located above the temperature control characteristic, the fuel is excessive. The fuel flow rate command CSO is decreased by a predetermined amount.

  The fuel flow rate command CSO ′ adjusted by the fuel adjustment unit 43 is output to the fuel valve opening degree determination unit 32, and the valve opening degree according to the fuel flow rate command CSO ′ is determined. Thereby, the opening degree of the fuel control valve 26 is adjusted based on the valve opening degree determined by the fuel valve opening degree determining unit 32.

Next, the correction unit 41 will be described with reference to FIG.
FIG. 4 is a functional block diagram of the correction unit 41. As illustrated in FIG. 4, the correction unit 41 includes a first processing unit 51, a second processing unit 52, and a third processing unit 53.

The first processing unit 51 estimates the flow rate of air flowing through the bypass flow path 16 (hereinafter referred to as “extraction flow rate”). The first processing unit 51 obtains, as input information, a valve capacity coefficient Cv obtained from the input pressure P ₁ of the bypass valve 18, the input differential pressure ΔP, and the valve opening, for example. The extraction flow rate is estimated by using the function of

  The second processing unit 52 holds, for example, second information in which a parameter related to the extraction flow rate and the correction amount are associated, and the correction amount is calculated from the extraction flow rate estimated by the first processing unit 51 and the second information. Ask.

  For example, when the extraction flow rate decreases, the amount of cold air flowing to the turbine 13 decreases, so that the exhaust gas temperature rises when compared at the same cabin pressure. Further, when the extraction flow rate decreases, the flow rate of air (air used for combustion) passing through the turbine 13 increases, and the fuel flow rate and output also increase. Therefore, when the extraction flow rate decreases, the flow rate of air passing through the turbine 13 increases. Therefore, in order to keep the turbine inlet temperature constant, it is necessary to increase the fuel. Therefore, it is necessary to correct the temperature control characteristic shown in FIG. 3 in the positive direction, that is, in the direction in which the exhaust gas temperature rises with respect to the same cabin pressure.

  When the bleed flow rate increases, the amount of cold air flowing to the turbine increases, so that the exhaust gas temperature decreases when compared with the same casing pressure. Further, when the extraction flow rate increases, the flow rate of air passing through the turbine (air used for combustion) decreases, and the fuel flow rate and output also decrease. Therefore, when the extraction flow rate increases, the flow rate of air passing through the turbine decreases. Therefore, in order to keep the turbine inlet temperature constant, it is necessary to reduce the fuel. Therefore, it is necessary to correct the temperature control characteristics shown in FIG. 3 in the negative direction, that is, in a direction in which the exhaust gas temperature decreases with respect to the same cabin pressure.

  From such a relationship, for example, the second information has a relationship as shown in FIG. In FIG. 5, the horizontal axis represents the difference ΔQ between the extraction flow rate and a preset reference extraction flow rate, and the vertical axis represents the correction amount. When the extraction flow rate is smaller than the reference extraction flow rate, the correction amount increases in proportion to the difference ΔQ. When the extraction flow rate is higher than the reference extraction flow rate, the correction amount decreases in proportion to the difference ΔQ. It is said that.

  The third processing unit 53 corrects the temperature adjustment characteristic stored in the storage unit 40 based on the correction amount determined by the second processing unit 52, and updates the temperature adjustment characteristic of the storage unit 40. Thereby, it becomes possible to make the temperature control characteristic stored in the memory | storage part 40 into a suitable curve according to the driving | operation of the gas turbine at that time.

  Next, the operation of the gas turbine control device 14 of the power generation system having the above configuration will be described with reference to FIG. Here, the control by the temperature control unit 31 which is one of the main features of the present invention will be mainly described. FIG. 6 is a flowchart showing a procedure of processing executed by the temperature control unit 31.

  First, when the operation of the gas turbine is started and the condition for starting the temperature control of the gas turbine is satisfied (“YES” in step SA1), it is determined whether or not the opening degree of the bypass valve 18 has changed. (Step SA2). As a result, when the opening degree of the bypass valve 18 has changed ("YES" in step SA2), a correction amount is obtained based on the opening degree of the bypass valve 18 and the like, and the temperature is adjusted based on this correction amount. The characteristic is corrected (step SA3). Subsequently, it is determined whether or not the inlet temperature of the turbine 13 is constant based on the corrected temperature control characteristics (step SA4). As a result, when it is determined that the inlet temperature of the turbine 13 is not constant. ("NO" in step SA4), the fuel supply amount determined by the fuel flow rate determining unit 30 is increased or decreased by a predetermined amount (step SA5). On the other hand, when it is determined in step SA4 that the inlet temperature of the turbine 13 is constant (“YES” in step SA4), the process proceeds to step SA6. In step SA6, it is determined whether or not an operation for stopping the gas turbine has been performed. If not, the process returns to step SA2, and the processes in and after step SA2 are performed again. This process ends.

  As described above, according to the gas turbine, the gas turbine control device, and the power generation system according to the present embodiment, the temperature control characteristic is corrected based on the flow rate of air flowing through the bypass passage 16, so that the bypass is performed. Appropriate temperature control characteristics according to the air flow rate can be obtained. Then, it is determined whether or not the inlet temperature of the turbine 13 is constant based on the temperature control characteristic reflecting the bypassed air flow rate. If it is determined that the inlet temperature of the turbine 13 is not constant, the inlet of the turbine 13 is determined. The flow rate of the fuel supplied to the combustor 12 is adjusted so that the temperature becomes constant. As a result, the flow rate of the bleed air bypassing the combustor 12 can be reflected in the operation, and a more stable operation can be realized.

  In the present embodiment, the correction amount is obtained based on the difference between the air flow rate flowing through the bypass flow path 16 and the reference air flow rate, but further, the correction amount is determined in consideration of other parameters. It is good. For example, the correction value may be obtained using a value obtained by dividing the difference between the air flow rate flowing through the bypass passage 16 and a preset reference air flow rate by the air flow rate at the compressor inlet. Thus, by determining the correction amount in consideration of the air flow rate at the compressor inlet, it is possible to obtain more appropriate temperature control characteristics.

DESCRIPTION OF SYMBOLS 10 Gas turbine 11 Compressor 12 Combustor 13 Turbine 14 Gas turbine control apparatus 16 Bypass flow path 18 Bypass valve 20 Generator 30 Fuel flow rate determination part 31 Temperature control part 32 Fuel valve opening degree determination part 40 Storage part 41 Correction part 42 Determination unit 43 Fuel adjustment unit

Claims (8)

A gas turbine comprising a compressor, a combustor, and a turbine,
Is connected to the turbine from the compressor, the air compressed by the compressor, and the bypass flow path for supplying a cooling air for cooling the turbine bypasses the combustor,
A flow rate adjusting means for adjusting an air flow rate provided in the bypass flow channel and flowing through the bypass flow channel;
Used to keep the inlet temperature of the turbine constant, the first information indicating a parameter of relationships for the inlet temperature of the turbine,
And correcting means for correcting the first information on the basis of parameters related to the air flow rate or air flow rate flowing through the bypass passage,
Wherein when the first information is corrected by the correction means, the gas turbine inlet temperature of the turbine by using the first information comprises a determination means for determining whether a constant corrected.   The fuel adjustment means for adjusting the amount of fuel supplied to the combustor based on a flow rate of air flowing through the bypass flow path or a parameter related to the flow rate of air when it is determined that an inlet temperature of the turbine is not constant. The gas turbine according to 1. The flow rate adjusting means is a valve;
3. The gas turbine according to claim 1, wherein the flow rate of air flowing through the bypass passage is estimated based on a valve opening degree of the valve and a differential pressure before and after the valve. The correction means includes
4. The first information is corrected according to claim 1, wherein the first information is corrected using a value obtained by dividing a difference between an air flow rate flowing through the bypass flow path and a preset reference air flow rate by an air flow rate at the compressor inlet. A gas turbine according to any one of the above. The first information is a temperature control characteristic that associates the casing pressure and the exhaust gas temperature on the downstream side of the final stage of the turbine,
The said determination means determines that the inlet temperature of the said turbine is not constant when the relationship between the said vehicle interior pressure and the said exhaust gas temperature remove | deviates from the said temperature control characteristic exceeding a predetermined tolerance. The gas turbine according to any one of 4.   The gas turbine according to claim 3, wherein the correction unit corrects the first information when the valve opening degree of the valve changes. A gas turbine according to any one of claims 1 to 6,
A power generation system comprising: a power generator generated by the gas turbine. A compressor,
A combustor,
A turbine,
Is connected to the turbine from the compressor, the air compressed by the compressor, and the bypass flow path for supplying a cooling air for cooling the turbine bypasses the combustor,
A gas turbine control device for controlling a gas turbine, which is provided in the bypass flow path and includes a flow rate adjusting means for adjusting a flow rate of air flowing through the bypass flow path;
Used to keep the inlet temperature of the turbine constant, the first information indicating a parameter of relationships for the inlet temperature of the turbine,
And correcting means for correcting the first information on the basis of parameters related to the air flow rate or air flow rate flowing through the bypass passage,
Wherein when the first information is corrected by the correction means, corrected of the gas turbine control device inlet temperature of the turbine by using the first information comprises a determination means for determining whether a constant .

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