JP5550461B2 - Gas turbine combined cycle plant and purge method for gas turbine combined cycle plant - Google Patents

Description

  The present invention relates to a gas turbine combined cycle plant and a purge method for a gas turbine combined cycle plant.

  A gas turbine combined cycle (Gas Turbine Combined Cycle) plant drives a steam turbine by steam of an exhaust gas boiler (hereinafter referred to as “HRSG”) that recovers heat from exhaust gas exhausted from the gas turbine.

  When a gas turbine combined cycle plant shifts from a gas turbine cycle to a combined cycle including a steam turbine, it is necessary to purge the gas remaining in the exhaust gas boiler.

  Here, when purging using the exhaust gas from the gas turbine, there is a possibility that flammable gas may remain in the exhaust gas boiler. Therefore, according to the safety standard NFPA 85 by the American Fire Protection Association, the exhaust gas from the gas turbine It is said that the exhaust gas cannot be used for the purge unless the temperature is 100 ° F. (37.8 ° C.) or less.

  For this reason, in Patent Document 1, after adjusting or repositioning the gas turbine inlet guide vane (IGV) to lower the gas turbine exhaust temperature to a necessary temperature range, it is provided between the gas turbine and the HRSG. A technique for opening the exhaust bypass damper to the purge position is described.

JP 2009-8076 A

  However, in the technique described in Patent Document 1, since the gas turbine must be operated so that the exhaust temperature is lowered in order to purge HRSG, a waiting time is generated until the exhaust temperature is lowered, and the time required for the purge is increased. The operation efficiency of the gas turbine combined cycle plant is also reduced.

  The present invention has been made in view of such circumstances, and it is possible to shorten the time required for purging the exhaust gas boiler and to purge the gas turbine combined cycle plant and the gas turbine combined cycle plant, which suppresses the decrease in operating efficiency. It aims to provide a method.

  In order to solve the above problems, the gas turbine combined cycle plant of the present invention employs the following means.

That is, the gas turbine combined cycle plant according to the present invention is driven by a compression unit that compresses air to generate compressed air, and a combustion gas generated by combustion of fuel and the compressed air generated by the compression unit. A gas turbine that exhausts exhaust gas from an exhaust port; an exhaust gas boiler that is connected to the exhaust port via a flow path and generates heat by recovering heat from the exhaust gas; and provided in the flow path, A smoke pipe that discharges to the atmosphere, a first position that is provided in the flow path, allows the exhaust gas to flow into the smoke pipe and blocks the flow into the exhaust gas boiler, and allows the exhaust gas to flow into the exhaust gas boiler and to the smoke pipe A shut-off means located at any one of the second positions for shutting off the inflow of air and compressed air generated by the compressing means is extracted into the exhaust gas boiler. And extraction pipe for causing the provided extraction pipe, the compressed air in the open state is bled to the exhaust gas boiler, and switching means for blocking the bleed to the exhaust gas boiler of the compressed air in the closed state, the exhaust gas When purging the gas in the boiler, when the gas turbine is in operation, the shut-off means is located at the first position, the opening / closing means is open, and the purge is completed. Control means for controlling the blocking means and the opening / closing means so that the blocking means is located at the second position and the opening / closing means is closed.

  According to the present invention, the gas turbine is driven by the combustion gas generated by the combustion of the fuel and the compressed air generated by the compression means, and exhausts the exhaust gas from the exhaust port. And the exhaust gas boiler connected to the exhaust port of the gas turbine through the flow path recovers heat from the exhaust gas of the gas turbine to generate steam. Further, the flow path has a first position where the exhaust gas flows into the smoke pipe that releases the exhaust gas to the atmosphere and blocks the inflow to the exhaust gas boiler, and a second position that allows the exhaust gas to flow into the exhaust gas boiler and blocks the flow into the smoke pipe. A blocking means located anywhere is provided.

  That is, when the shut-off means is located at the first position, power generation by the exhaust gas boiler is not performed, and when the shut-off means is located at the second position, power generation by the gas turbine and power generation by the exhaust gas boiler are performed. .

  Here, before power generation by the exhaust gas boiler, the gas remaining in the exhaust gas boiler must be purged.

According to the present invention, the gas turbine combined cycle plant is provided with an extraction pipe for extracting compressed air to the exhaust gas boiler, and the extraction pipe is used for extracting compressed air to the exhaust gas boiler in the open state and compressing in the closed state. Opening and closing means for blocking air extraction from the exhaust gas boiler is provided. When purging the gas in the exhaust gas boiler by the control means, when the purge is completed when the shut-off means is located at the first position and the opening / closing means is opened while the gas turbine is driven. The blocking means and the opening / closing means are controlled so that the blocking means is located at the second position and the opening / closing means is closed.

  As a result, since the exhaust gas boiler can be purged even when the gas turbine is being driven, it is possible to shorten the time required for purging the exhaust gas boiler and to suppress a decrease in operating efficiency.

  The gas turbine combined cycle plant of the present invention may further include a cooling means for cooling the compressed air flowing through the extraction pipe by cooling the extraction pipe.

  According to the present invention, since the compressed air flowing through the extraction pipe is cooled by the cooling means, compressed air having a higher compression ratio can be used to purge the exhaust gas boiler.

  The gas turbine combined cycle plant of the present invention further includes a temperature measuring means for measuring the temperature in the exhaust gas boiler, and the cooling means has a temperature measured in advance by the temperature measuring means. As described above, the cooling amount for the extraction pipe may be controlled.

  According to the present invention, since the cooling amount for the extraction pipe by the cooling means is controlled so that the temperature measured by the temperature measuring means becomes a predetermined temperature, the temperature of the compressed air extracted to the exhaust gas boiler is further increased. It can be controlled with high accuracy.

  In the gas turbine combined cycle plant of the present invention, condensing means for returning steam to water, heat exchange means for exchanging heat between the compressed air flowing through the extraction pipe and water supplied from the condensing means, May be further provided.

  According to the present invention, the heat exchange means exchanges the heat of the compressed air flowing through the extraction pipe into the water supplied from the condensing means, so that the compressed air having a higher compression ratio can be obtained using existing equipment. It can be used to purge exhaust gas boilers.

  On the other hand, in order to solve the above-mentioned problems, the following method is adopted in the purge method for the gas turbine combined cycle plant of the present invention.

That is, the gas turbine combined cycle plant purging method according to the present invention includes a compression unit that compresses air to generate compressed air, and a combustion generated by combustion of fuel and the compressed air generated by the compression unit. A gas turbine that is driven by gas and exhausts exhaust gas from an exhaust port; an exhaust gas boiler that is connected to the exhaust port via a flow path and recovers heat from the exhaust gas to generate steam; and is provided in the flow path. A smoke pipe that discharges the exhaust gas to the atmosphere, a first position that allows the exhaust gas to flow into the smoke pipe and blocks the inflow to the exhaust gas boiler, and an exhaust gas that flows into the exhaust gas boiler and blocks the inflow to the smoke pipe A gas turbine combined cycle plant purge method comprising: In a state where the bottle is driven, the first step of positioning the blocking means at the first position and the opening / closing means provided in the extraction pipe for extracting the compressed air to the exhaust gas boiler are opened. Thus, when the compressed air extracted to the exhaust gas boiler reaches a predetermined amount, a second step of extracting the compressed air to the exhaust gas boiler is closed, and the compressed air is closed. A third step of blocking the extraction of the exhaust gas to the exhaust gas boiler, and a fourth step of positioning the blocking means at the second position.

  According to the present invention, the gas turbine combined cycle plant is provided with an extraction pipe for extracting compressed air to the exhaust gas boiler, and the extraction pipe is used for extracting compressed air to the exhaust gas boiler in the open state and compressing in the closed state. Opening / closing means for blocking air extraction from the gas boiler is provided. In the present invention, when purging the gas in the exhaust gas boiler, when the gas turbine is driven, the shut-off means is positioned at the first position, the opening / closing means is opened, and the purge is completed. The blocking means and the opening / closing means are controlled so that the blocking means is positioned at the second position and the opening / closing means is closed.

  As a result, since the exhaust gas boiler can be purged even when the gas turbine is being driven, it is possible to shorten the time required for purging the exhaust gas boiler and to suppress a decrease in operating efficiency.

  The time required for purging the exhaust gas boiler can be shortened, and a decrease in operating efficiency can be suppressed.

It is a mimetic diagram showing the composition of the gas turbine combined cycle plant concerning a 1st embodiment of the present invention. It is a flowchart which shows the flow of the exhaust gas boiler purge process which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the gas turbine combined cycle plant which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the flow of the exhaust gas boiler purge process which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the structure of the gas turbine combined cycle plant which concerns on 3rd Embodiment of this invention. It is a flowchart which shows the flow of the exhaust gas boiler purge process which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the structure of the gas turbine combined cycle plant which concerns on 4th Embodiment of this invention.

  Below, one embodiment of the gas turbine combined cycle (henceforth "GTCC") plant 10 concerning the present invention is described with reference to drawings.

[First Embodiment]
The first embodiment of the present invention will be described below.

  FIG. 1 shows a configuration of a GTCC plant 10 according to the first embodiment.

  The GTCC plant 10 includes a compressor 12 that compresses air to generate compressed air, a combustor 14 that burns fuel and compressed air generated by the compressor 12 to generate combustion gas, and a combustor 14 that generates the combustion gas. A gas turbine 16 that is driven by the generated combustion gas and exhausts exhaust gas from an exhaust port; an exhaust gas boiler 20 that is connected to the exhaust port via a bypass 18 and generates heat by recovering heat from the exhaust gas; and a bypass 18 And a smoke pipe 22 for releasing the exhaust gas exhausted from the gas turbine 16 to the atmosphere.

  The gas turbine 16 is connected to a power generator (not shown) and generates power by rotating the connected power generator. The steam generated in the exhaust gas boiler 20 drives a steam turbine (not shown), and the rotational energy of the steam turbine is converted into electric power.

  Moreover, as fuel used with the combustor 14, light fuels, such as natural gas, city gas, kerosene, light oil, gasoline, A heavy oil, are used, for example.

  Further, in the bypass 18, the exhaust gas exhausted from the gas turbine 16 flows into the smoke pipe 22 and the first position where the inflow to the exhaust gas boiler 20 is blocked, and the exhaust gas flows into the exhaust gas boiler 20 and enters the smoke pipe 22. An exhaust bypass damper 24 is provided at any one of the second positions where the inflow is blocked.

  The case where the exhaust bypass damper 24 is located at the first position is a case where power generation by the exhaust gas boiler is not performed because the exhaust gas exhausted from the gas turbine 16 does not flow into the exhaust gas boiler 20. On the other hand, the case where the exhaust bypass damper 24 is located at the second position means that the exhaust gas exhausted from the gas turbine 16 flows into the exhaust gas boiler 20, so that the GTCC plant 10 generates power from the gas turbine 16 and the exhaust gas boiler. This is a case where power generation by 20 is combined.

Furthermore, the GTCC plant 10 includes an extraction pipe 26 for extracting the compressed air from the compressor 12 to the exhaust gas boiler 20. The bleed pipe 26 is provided with a valve 28 that bleeds compressed air to the exhaust gas boiler 20 in the open state and shuts out the bleed air of the compressed air to the exhaust gas boiler 20 in the closed state.

  The compressed air extracted to the exhaust gas boiler 20 through the extraction pipe 26 is a part of the compressed air generated by the compressor 12. The opening degree of the valve 28 can be adjusted, and the amount of compressed air extracted from the compressor 12 to the exhaust gas boiler 20 may be arbitrarily changed.

  Further, the exhaust bypass damper 24 is driven by the damper driving unit 30 so as to be located at either the first position or the second position, and the valve 28 is driven by the valve driving unit 32 to be in the open state or the closed state. One of the states is set.

  The GTCC plant 10 includes a control unit 34 that controls the entire GTCC plant 10.

  When purging the gas in the exhaust gas boiler 20, the control unit 34 according to the first embodiment is configured such that the exhaust bypass damper 24 is positioned at the first position and the valve 28 is Exhaust gas boiler purge processing is performed to control the exhaust bypass damper 24 and the valve 28 so that the exhaust bypass damper 24 is positioned at the second position and the valve 28 is closed when the purge is completed. To do.

  Next, the operation of the GTCC plant 10 according to the first embodiment will be described.

  FIG. 2 is a flowchart showing the flow of the exhaust gas boiler purge process executed by the control unit 34. The exhaust gas boiler purge program for executing the exhaust gas boiler purge process shown in FIG. It is stored in advance in a predetermined area of the storage means shown. The valve 28 is closed before the exhaust gas boiler purge process is executed.

  First, in step 100, it is determined whether or not the exhaust bypass damper 24 is located at the first position. If the determination is affirmative, the process proceeds to step 104. If the determination is negative, the process proceeds to step 102. . That is, the case where a negative determination is made in this step is a case where the exhaust bypass damper 24 is located at the second position.

  In step 102, a first movement signal is transmitted to the damper drive unit 30 so that the exhaust bypass damper 24 is positioned at the first position, and the routine proceeds to step 104. When receiving the first movement signal transmitted from the control unit 34, the damper driving unit 30 moves the exhaust bypass damper 24 from the second position to the first position.

  In step 104, an open signal is transmitted to the valve drive unit 32 so that the valve 28 is opened. When the valve drive unit 32 receives the open signal transmitted from the control unit 34, the valve drive unit 32 opens the valve 28.

  In the next step 106, it is determined whether or not a predetermined amount of air has been extracted to the exhaust gas boiler 20. If the determination is affirmative, the process proceeds to step 108. If the determination is negative, the predetermined amount of air is determined to be the exhaust gas boiler. It will be in a waiting state until it bleeds to 20. That is, the case where this step is affirmative indicates that the exhaust gas boiler 10 has been purged.

  In the first embodiment, the predetermined air amount is set to an air amount that is three times the volume of the exhaust gas boiler 20 as an example, but the predetermined air amount is an amount that can purge the exhaust gas boiler 20. Well, not limited to this. In the GTCC plant 10 according to the first embodiment, the case where an affirmative determination is made in step 106 is a case where a previously derived time has elapsed until a predetermined amount of air is extracted, but is not limited thereto. Alternatively, the amount of air extracted into the exhaust gas boiler 20 may be measured, and the measurement result may be a predetermined amount of air.

  In step 108, a close signal is transmitted to the valve drive unit 32 so that the valve 28 is closed. When the valve drive unit 32 receives the close signal transmitted from the control unit 34, the valve drive unit 32 closes the valve 28.

  In the next step 110, a second movement signal is transmitted to the damper drive unit 30 so that the exhaust bypass damper 24 is positioned at the second position. Upon receiving the second movement signal transmitted from the control unit 34, the damper driving unit 30 moves the exhaust bypass damper 24 from the first position to the second position, and ends the program.

  As described above, when the gas in the exhaust gas boiler 20 is purged, the GTCC plant 10 according to the first embodiment moves the exhaust bypass damper 24 to the first position while the gas turbine 16 is driven. When the purge is finished, the exhaust bypass damper 24 is positioned at the second position and the valve 28 is closed, so that the exhaust gas can be exhausted even when the gas turbine 16 is driven. The boiler can be purged, the time required for purging the exhaust gas boiler can be shortened, and a decrease in operating efficiency can be suppressed.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.

  FIG. 3 shows a configuration of the GTCC plant 10 according to the second embodiment. 3 that are the same as in FIG. 1 are assigned the same reference numerals as in FIG. 1, and descriptions thereof are omitted.

  The GTCC plant 10 according to the second embodiment includes a cooling device 40 that cools the extraction pipe 26 to cool the compressed air flowing through the extraction pipe 26. The cooling device 40 according to the second embodiment includes a spray unit 42 that sprays water on the extraction pipe 26, and the spray unit 42 is connected to a water supply tank (not shown) via a water supply pipe 44. ing. Then, by opening the valve 46 provided in the water supply pipe 44, water is sprayed from the spray section 42 to the extraction pipe 26.

  The valve 46 is brought into either an open state or a closed state by the valve drive unit 48.

  Further, the control unit 34 controls the start and stop of the cooling by the cooling device 40 by controlling the valve driving unit 48.

  Next, the operation of the GTCC plant 10 according to the second embodiment will be described.

  FIG. 4 is a flowchart showing the flow of the exhaust gas boiler purge process executed by the control unit 34 according to the second embodiment, and the exhaust gas boiler purge program for executing the exhaust gas boiler purge process shown in FIG. It is stored in advance in a predetermined area of a storage means (not shown) provided in the unit 34. In the following description of FIG. 4, the same processes as those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, the description thereof is omitted, and the processes different from the exhaust gas boiler purge process shown mainly in FIG. explain.

  When an affirmative determination is made at step 100 and when the processing shown at step 102 is completed, the routine proceeds to step 200.

  In step 200, a cooling start signal is transmitted to the cooling device 40 so as to start cooling the extraction pipe 26, and the routine proceeds to step 104. When the cooling device 40 receives the cooling start signal transmitted from the control unit 34, the cooling device 40 starts cooling the extraction pipe 26. In the second embodiment, the cooling device 40 starts spraying water on the extraction pipe 26.

  In step 108, a close signal is transmitted to the valve drive unit 32 so that the valve 28 is closed, and the process proceeds to step 202.

  In step 202, a cooling stop signal is transmitted to the cooling device 40 so as to stop cooling of the extraction pipe 26, and the routine proceeds to step 110. When the cooling device 40 receives the cooling stop signal transmitted from the control unit 34, the valve driving unit 48 closes the valve 46. As a result, the cooling device 40 stops spraying water onto the extraction pipe 26, and thus cooling of the extraction pipe 26 is stopped.

  As described above, in the GTCC plant 10 according to the second embodiment, since the compressed air flowing through the extraction pipe 26 is cooled by the cooling device 40, the exhaust gas boiler 20 is purged with compressed air having a higher compression ratio. Can be used to

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described.

  FIG. 5 shows a configuration of the GTCC plant 10 according to the third embodiment. 5 that are the same as those in FIG. 3 are assigned the same reference numerals as in FIG. 3 and descriptions thereof are omitted.

  The GTCC plant 10 according to the third embodiment includes a temperature measurement unit 50 that measures the temperature in the exhaust gas boiler 20 using a temperature sensor and outputs temperature information indicating the temperature. The temperature measurement unit 50 according to the third embodiment uses a thermocouple as a temperature sensor, but is not limited to this, and other contact type temperature sensors such as a resistance temperature sensor, and a non-contact type such as an infrared temperature sensor. You may use other temperature sensors, such as this temperature sensor.

  The control unit 34 controls the temperature cooling device 40 to start and stop the cooling, and also measures the temperature measured by the temperature measurement unit 50 (hereinafter referred to as “measurement temperature”) and the exhaust gas boiler 20. The temperature is compared with a predetermined temperature (for example, 100 ° F. (37.8 ° C.), hereinafter referred to as “set temperature”) as a suitable temperature for purging. And the control part 34 controls the cooling amount with respect to the extraction pipe 26 of the cooling device 40 so that the temperature measured by the temperature measurement part 50 turns into setting temperature.

  Next, the operation of the GTCC plant 10 according to the third embodiment will be described.

  FIG. 6 is a flowchart showing the flow of the exhaust gas boiler purge process executed by the control unit 34 according to the third embodiment, and the exhaust gas boiler purge program for executing the exhaust gas boiler purge process shown in FIG. It is stored in advance in a predetermined area of a storage means (not shown) provided in the unit 34. In the following description of FIG. 6, the same processes as those in FIG. 4 are denoted by the same reference numerals as those in FIG. 4, the description thereof is omitted, and the processes different from the exhaust gas boiler purge process shown mainly in FIG. explain.

  In step 104, an open signal is transmitted to the valve drive unit 32 so that the valve 28 is in an open state, and the process proceeds to step 300.

  In step 300, temperature information indicating the magnitude of the measured temperature of the exhaust gas boiler 20 is acquired from the temperature measuring unit 50.

  In the next step 302, it is determined whether or not the measured temperature indicated by the temperature information acquired in step 300 is equal to or lower than the set temperature. If the determination is affirmative, the process proceeds to step 106. The process proceeds to step 304.

  In step 304, after a cooling amount increase signal for increasing the cooling amount for the extraction pipe 26 by the cooling device 40 is transmitted to the cooling device 40, the process proceeds to step 106. When receiving the cooling amount increase signal transmitted from the control unit 10, the cooling device 40 increases the amount of water sprayed on the extraction pipe 26 by a preset amount.

  In step 106, it is determined whether or not a predetermined amount of air has been extracted into the exhaust gas boiler 20. If the determination is affirmative, the process proceeds to step 108. If the determination is negative, the process returns to step 300.

  As described above, in the GTCC plant 10 according to the third embodiment, the cooling amount for the extraction pipe 26 by the cooling device 40 is controlled so that the measured temperature measured by the temperature measuring unit 50 becomes the set temperature. Therefore, the temperature of the compressed air extracted to the exhaust gas boiler 20 can be controlled with higher accuracy.

[Fourth Embodiment]
The fourth embodiment of the present invention will be described below.

  FIG. 7 shows the configuration of the GTCC plant 10 according to the fourth embodiment. In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The GTCC plant 10 according to the fourth embodiment includes a condenser 60 that returns steam generated in the exhaust gas boiler 20 to water (saturated water), compressed air that flows through the extraction pipe 26, and water supplied from the condenser 60. And a heat exchanger 62 for exchanging heat with each other.

  The water from the condenser 60 is supplied to the heat exchanger 62 through the water supply pipe 66 by the condensate pump 64. The feed water pipe 66 branches into a feed water pipe 66A that reaches the exhaust gas boiler 20 via the heat exchanger 62 and a feed water pipe 66B that leads to the exhaust gas boiler 20 without going through the heat exchanger 62 and before the exhaust water boiler 20 is reached. Join again.

  The compressed air extracted from the compressor 12 is heat-exchanged with the water supplied from the condenser 60 by the heat exchanger 62. As a result, the temperature of the compressed air decreases, and the compressed air whose temperature has decreased is sent to the exhaust gas boiler 20. On the other hand, the water supplied to the heat exchanger 62 is supplied to the exhaust gas boiler 20 together with the water flowing through the water supply pipe 66B.

  As described above, the GTCC plant 10 according to the fourth embodiment exchanges heat between the compressed air flowing through the extraction pipe 26 and the water supplied from the condenser 60 by the heat exchanger 62. The compressed air having a higher compression ratio can be used for purging the exhaust gas boiler 20.

  As mentioned above, although this invention was demonstrated using said each embodiment, the technical scope of this invention is not limited to the range as described in each said embodiment. Various changes or improvements can be added to the above-described embodiments without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention.

  For example, in the second and third embodiments, the case where a spray device that sprays water on the extraction pipe 26 is used as the cooling device 40 has been described. However, the present invention is not limited to this, and the cooling device 40 is used. As another example, another cooling device such as a cooling device using a thermoelectric element such as a Peltier element may be used. When a blower is used as the cooling device 40, the amount of blown air to the extraction pipe 26 is increased in step 304 of the exhaust gas boiler purge process according to the third embodiment. When a cooling device using a thermoelectric element is used as the cooling device 40, the amount of voltage applied to the thermoelectric element is increased in step 304.

  Moreover, although the said 4th Embodiment demonstrated the case where the condenser which returns the vapor | steam generate | occur | produced in the exhaust gas boiler 20 to water as the condenser 60 was demonstrated, this invention is not limited to this, As the condenser 60, a condenser that returns steam generated in another boiler to water may be used.

  Furthermore, the second embodiment and the fourth embodiment may be combined. Furthermore, the third embodiment and the fourth embodiment may be combined.

DESCRIPTION OF SYMBOLS 10 GTCC plant 12 Compressor 16 Gas turbine 20 Exhaust gas boiler 22 Smoke pipe 24 Exhaust bypass damper 26 Extraction pipe 28 Valve 34 Control part

Claims (5)

Compression means for compressing air to generate compressed air;
A gas turbine driven by combustion gas generated by combustion of fuel and the compressed air generated by the compression means, and exhausting exhaust gas from an exhaust port;
An exhaust gas boiler that is connected to the exhaust port via a flow path and generates steam by recovering heat from the exhaust gas;
A smoke pipe provided in the flow path for discharging the exhaust gas to the atmosphere;
A second position provided in the flow path for allowing the exhaust gas to flow into the smoke pipe and blocking the flow into the exhaust gas boiler; and a second position for allowing the exhaust gas to flow into the exhaust gas boiler and blocking the flow into the smoke pipe. A blocking means located at any of the positions;
An extraction pipe for extracting the compressed air generated by the compression means to the exhaust gas boiler;
Wherein provided in the extraction pipe, the compressed air in the open state is bled to the exhaust gas boiler, and switching means for blocking the bleed to the exhaust gas boiler of the compressed air in the closed state,
When purging the gas in the exhaust gas boiler, when the gas turbine is driven, the shut-off means is located at the first position, the open / close means is opened, and the purge is completed. Control means for controlling the blocking means and the opening / closing means so that the blocking means is located at the second position and the opening / closing means is in a closed state;
Gas turbine combined cycle plant equipped with.   The gas turbine combined cycle plant according to claim 1, further comprising cooling means for cooling the compressed air flowing through the extraction pipe by cooling the extraction pipe. Further comprising a temperature measuring means for measuring the temperature in the exhaust gas boiler,
The gas turbine combined cycle plant according to claim 2, wherein the cooling unit controls a cooling amount for the extraction pipe so that a temperature measured by the temperature measuring unit becomes a predetermined temperature. Condensing means for returning steam to water;
Heat exchange means for exchanging heat between the compressed air flowing through the extraction pipe and water supplied from the condensing means;
The gas turbine combined cycle plant according to claim 1, further comprising: A compression unit that compresses air to generate compressed air, a gas turbine that is driven by combustion gas generated by combustion of fuel and the compressed air generated by the compression unit, and exhausts exhaust gas from an exhaust port; An exhaust gas boiler that is connected to the exhaust port via a flow path and generates steam by recovering heat from the exhaust gas, a smoke pipe that is provided in the flow path and discharges the exhaust gas to the atmosphere, and the exhaust gas is supplied to the smoke pipe A shut-off means located at any one of a first position for inflowing and blocking the inflow to the exhaust gas boiler, and a second position for allowing the exhaust gas to flow into the exhaust gas boiler and blocking the inflow to the smoke pipe. A gas turbine combined cycle plant purge method comprising:
A first step of positioning the shut-off means at the first position while the gas turbine is driven;
A second step of extracting the compressed air to the exhaust gas boiler by opening an open / close means provided in an extraction pipe for extracting the compressed air to the exhaust gas boiler;
A third step of shutting off the extraction of the compressed air to the exhaust gas boiler by closing the opening and closing means when the compressed air extracted to the exhaust gas boiler reaches a predetermined amount;
A fourth step of positioning the blocking means at the second position;
A purge method for a gas turbine combined cycle plant including:

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