JP2002161710A - Steam cooling device of gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control the amount of steam introduced into a burner 117 eliminating the need for installing an expensive valve device in a steam channel 116. SOLUTION: An outlet steam in a middle pressure drum 106 is supplied from the steam channel 116 into the burner 117 as cooling steam, the amount of steam introduced into the burner 117 is adjusted by controlling opening/ closing of a first flow amount control valve 112 with a control means 125 such that the pressure of the middle pressure drum 106 is set to a set value in accordance with the loading condition of a gas turbine 101. The amount of steam required in accordance with the load condition of the gas turbine 101 is supplied to the burner 117 and the flow amount of steam introduced into the burner 11 is properly controlled by controlling the existing first flow amount control valve 112 to maintain the pressure of the middle pressure drum 106 at a predetermined state eliminating the need for installing an expensive valve device in the steam channel 116.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine steam cooling system for cooling a high-temperature component such as a gas turbine combustor with steam from an exhaust heat recovery boiler or auxiliary steam.

[0002]

2. Description of the Related Art From the viewpoints of effective use of energy resources and economic efficiency, various high efficiencies have been achieved in power generation facilities (power generation plants). A turbine power plant (combined power plant) combining a gas turbine and a steam turbine is one of them. In a combined cycle power plant, high-temperature exhaust gas from a gas turbine is sent to an exhaust heat recovery boiler, where steam is generated via a superheating unit in the exhaust heat recovery boiler, and the generated steam is sent to a steam turbine and sent to a steam turbine. I am going to work.

[0003] High-temperature components such as a combustor of a gas turbine have been cooled by air, but with the recent rise in combustion temperature, they have been cooled by steam. Also in a combined cycle power plant, a gas turbine that cools a high-temperature component such as a combustor with steam is applied, and a highly efficient power plant is planned in combination with a steam turbine.

A conventional gas turbine steam cooling system employing steam as a cooling medium for a gas turbine combustor will be described with reference to FIG. FIG. 4 shows a schematic configuration showing a cooling system of a combined cycle power plant equipped with a conventional gas turbine steam cooling device.

As shown in FIG. 1, exhaust gas from a gas turbine 1 is sent to an exhaust heat recovery boiler 2, which includes a high pressure drum 3, a high pressure superheater 4, and a medium pressure A drum 5, a medium pressure superheater 6, and a reheater 7 are provided. The steam generated by the high-pressure drum 3 is sent to a high-pressure steam turbine 9 via a high-pressure superheater 4 by a high-pressure steam introduction path 8. The steam of the intermediate-pressure drum 5 is sent to an intermediate-pressure steam turbine 11 via an intermediate-pressure superheater 6 and a reheater 7 in order through an intermediate-pressure steam introduction path 10.

The outlet steam of the high-pressure steam turbine 9 is supplied to the reheater 7
The steam that has merged with the intermediate-pressure steam introduction path 10 on the inlet side of the steam generator and passed through the reheater 7 is sent to the medium-pressure steam turbine 11. A medium pressure drum pressure control valve 12 is provided in a medium pressure steam introduction passage 10 between the medium pressure superheater 6 and the reheater 7, and the steam pressure of the medium pressure drum 5 is controlled by opening / closing control of the medium pressure drum pressure control valve 12. Is adjusted to a predetermined state. Incidentally, reference numeral 20 in the drawing denotes a condenser.

Medium pressure superheater 6 and medium pressure drum pressure control valve 12
Between the medium pressure steam introduction passage 10 and the steam cooling passage 14
Are provided in a branched manner, and the steam cooling path 14
Through the combustor 13, which is a high-temperature component, and joins the medium-pressure steam introduction passage 10 on the downstream side of the reheater 7. That is, the combustor 1
3, the outlet steam (for example, 300 ° C.) of the intermediate pressure drum 5 is supplied as cooling steam from the steam cooling passage 14, and the steam (for example, 560 ° C. to 600 ° C.) used for cooling is supplied to the reheater 7. It merges with the outlet steam and is guided to the medium-pressure steam turbine 11.
A control valve 15 is provided in the steam cooling passage 14 on the inlet side of the combustor 13, and the amount of steam guided to the combustor 13 is adjusted by the control valve 15. The control valve 15 may be provided in the steam cooling passage 14 on the outlet side of the combustor 13 in some cases.

In the above-described steam cooling device for a gas turbine, the steam (for example, 300 ° C.) at the outlet of the intermediate pressure drum 5 is supplied from the steam cooling passage 14 to the combustor 13 as cooling steam.
Cooling of the combustor 13 is performed. The amount of steam guided to the combustor 13 is adjusted by the control valve 15, and a desired amount of steam is supplied to the combustor 13. The steam after cooling the combustor 13 is collected by the medium-pressure steam turbine 11. For this reason, it becomes a combined cycle power plant in which an efficient cooling system is constructed.

[0009]

In a conventional gas turbine steam cooling system, a control valve 15 is provided in a steam cooling passage 14 for adjusting the amount of cooling steam supplied to a combustor 13. . Since the steam cooling passage 14 is a passage for high-temperature steam, an expensive control valve 15 having excellent heat resistance is required, and the cost of parts is increased, leading to an increase in the construction cost of the combined cycle power plant. When the control valve 15 is provided on the outlet side of the combustor 13, a particularly expensive control valve 15 is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a desired amount of cooling steam is supplied to a gas turbine without providing a valve device for directly adjusting the amount of steam in a cooling steam introduction system from the exhaust heat recovery boiler. It is an object of the present invention to provide a gas turbine steam cooling device that can supply high-temperature components.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an exhaust heat recovery boiler for generating steam by exhaust gas from a gas turbine, and a steam operated by the steam generated by the exhaust heat recovery boiler. A turbine, a steam introduction passage for introducing steam from the waste heat recovery boiler to the steam turbine, and a steam cooling passage provided in the steam introduction passage for bypassing the steam from the waste heat recovery boiler for cooling high-temperature components of the gas turbine. A generated steam pressure detecting means for detecting a steam pressure generated in the exhaust heat recovery boiler, and a steam introduction path based on the detected information of the generated steam pressure detecting means for adjusting the steam pressure generated in the exhaust heat recovery boiler. A generated steam pressure control valve that controls the flow rate of steam, and a cooled steam temperature that is provided in a steam cooling passage on the downstream side of the hot component and that detects the steam temperature after cooling the hot component. Control means for controlling the opening and closing of the generated steam pressure control valve so that the detected value of the generated steam pressure detecting means becomes a set value in order to adjust the flow rate of steam flowing into the steam cooling path based on the state of the gas turbine. Control means for controlling the opening and closing of the generated steam pressure control valve in order to adjust the flow rate of steam flowing into the steam cooling path based on the detection information of the cooled steam temperature detecting means.

A steam cooling path is provided by branching from a steam introduction path from the medium pressure drum to the medium pressure steam turbine.
An intermediate-pressure drum pressure control valve is provided in the steam introduction path on the downstream side of the branch of the steam cooling path to provide a generated steam pressure control valve, and the control means introduces steam based on the detection information of the post-cooling steam temperature detection means. It is characterized in that a function is provided for controlling the opening and closing of the medium pressure drum pressure control valve so as to regulate the flow rate of the passage and secure the flow rate of the steam cooling passage.

Further, an auxiliary steam introduction passage for introducing steam from the high pressure drum is connected to a steam cooling passage, and an auxiliary steam pressure control valve is provided in the auxiliary steam introduction passage to serve as a generated steam pressure control valve. A function of controlling the flow rate of the auxiliary steam introduction path based on the detection information of the post-cooling steam temperature detection means and controlling the opening and closing of the auxiliary steam pressure control valve so as to secure the flow rate of the steam cooling path. It is characterized by.

The steam cooling passage is connected to an auxiliary steam introduction passage through which steam from the high-pressure drum is introduced. The auxiliary steam introduction passage is connected to an auxiliary fluid flow passage. Auxiliary steam temperature detection means for detecting the temperature of the auxiliary steam is provided in the auxiliary steam introduction path on the flow side, an auxiliary fluid pressure control valve is provided in the auxiliary fluid flow path to serve as a generated steam pressure control valve, and the control means includes cooling. Open / close control of the auxiliary steam pressure control valve is performed to control the flow rate of the auxiliary fluid flow path based on the detection information of the post-steam temperature detection means and the detection information of the auxiliary steam temperature detection means so as to secure the flow rate of the steam cooling path. Features are provided.

A steam cooling passage is provided branching from a steam introduction passage from the medium pressure drum to the medium pressure steam turbine, and an auxiliary steam introduction passage through which steam from the high pressure drum is introduced is connected to the steam cooling passage. A medium-pressure drum pressure control valve is provided in the steam introduction path on the downstream side of the branch of the steam cooling path to provide a generated steam pressure control valve, and an auxiliary steam pressure control valve is provided in the auxiliary steam introduction path to control generated steam pressure. Valve and the control means
The opening and closing of the medium pressure drum pressure control valve is controlled so as to secure the flow rate of the steam cooling path by regulating the flow rate of the steam introduction path based on the detection information of the post-cooling steam temperature detection means, and A function is provided to control the opening and closing of the auxiliary steam pressure control valve so as to control the flow rate of the auxiliary steam introduction path based on the detection information and secure the flow rate of the steam cooling path.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a combined cycle power plant including a gas turbine steam cooling device according to an embodiment of the present invention, and FIGS. 2 and 3 show control blocks of a generated steam pressure control valve.

As shown in FIG. 1, the exhaust gas from the gas turbine 101 is sent to an exhaust heat recovery boiler 102. The exhaust heat recovery boiler 102
03, the first high-pressure superheater 104, and the second high-pressure superheater 105
And a medium-pressure drum 106, a medium-pressure superheater 107, and a reheater 108. The steam generated in the high-pressure drum 103 is supplied to the first high-pressure superheater 104,
The high-pressure superheater 105 sends the high-pressure steam to the high-pressure steam turbine 110 from the high-pressure side steam introduction passage 109. High pressure steam turbine 1
The exhaust steam of 10 passes through a reheater 108 and passes through a steam introduction path 111.
From the steam turbine 112. The exhaust steam of the medium-pressure steam turbine 112 is supplied to the low-pressure steam turbine 11
3 and is condensed by the condenser 114 and collected by the exhaust heat recovery boiler 102. On the other hand, the steam of the intermediate-pressure drum 106 is sent to the intermediate-pressure steam turbine 112 from the intermediate-pressure side steam introduction passage 115 serving as a steam introduction passage, sequentially through the intermediate-pressure superheater 107 and the reheater 108.

A steam passage 116 is provided as a steam cooling passage branching from the medium pressure side steam introduction passage 115.
16 is a combustor 11 which is a high-temperature component of the gas turbine 101.
7 and joins the steam introduction passage 111 on the inlet side of the intermediate-pressure steam turbine 112. Also, the second
A high-pressure steam flow path 118 is provided branching from the high-pressure steam introduction path 109 on the downstream side of the high-pressure superheater 105. The high-pressure steam flow path 118 joins a steam flow path 116 on the front side of the gas turbine 101. An auxiliary fluid channel 119 into which water supplied from a medium pressure water pump is introduced merges with the high pressure steam channel 118.

A first flow rate control valve 120 (medium pressure drum pressure control valve) as a generated steam pressure control valve is provided in the intermediate pressure side steam introduction path 115 on the downstream side of the branch portion of the steam flow path 116. By opening and closing the flow control valve 120, the amount of steam flowing through the medium pressure side steam introduction path 115 (steam pressure of the medium pressure drum 106) is adjusted. Further, a second flow rate control valve 121 (auxiliary steam pressure control valve) as a generated steam pressure control valve is provided in the high-pressure steam flow path 118 on the upstream side of the junction of the auxiliary fluid flow path 119, and the second flow rate control valve is provided. By opening and closing the valve 121, the flow rate of the high-pressure steam introduced from the high-pressure steam channel 118 to the steam channel 116 is adjusted. That is, the steam flow path 116
The steam temperature is adjusted. Further, the auxiliary fluid flow path 119
Has a third flow control valve 122 as a generated steam pressure control valve.
(Auxiliary fluid pressure control valve), and the third flow control valve 1
By opening / closing 22, an appropriate amount of medium-pressure feed water is introduced into the high-pressure steam flow path 118, the temperature of the steam in the high-pressure steam flow path 118 is reduced, and the temperature of the high-pressure steam introduced into the steam flow path 116 is controlled to a predetermined temperature. Is done.

A temperature detecting means T1 is provided in the steam flow path 116 between the junction of the high-pressure steam flow path 118 and the gas turbine 101, and the gas turbine 1 is detected by the temperature detecting means T1.
The temperature of the steam introduced at 01 is detected. Steam channel 1
A differential pressure detecting means P1 for detecting a steam pressure difference between an inlet side and an outlet side of the 16 combustors 117 is provided, and a differential pressure of steam flowing through the combustor 117, that is, a flow rate is detected by the differential pressure detecting means P1. You. Further, a second temperature detecting means T3 as auxiliary steam temperature detecting means is provided in the high-pressure steam flow path 118 on the downstream side of the junction of the auxiliary fluid flow path 119, and the second temperature detecting means T3 controls the high-pressure steam flow path. A steam temperature at 118 is detected. In the figure, P2 is the combustor 1 of the steam flow path 116.
An inlet pressure detecting means for detecting a steam pressure on the inlet side of 17;
P3 is an outlet pressure detecting means for detecting the steam pressure on the outlet side of the combustor 117 in the steam passage 116, and T2 is a post-cooling steam temperature detecting means for detecting the steam temperature on the outlet side of the combustor 117 in the steam passage 116. Outlet temperature detecting means.

The temperature detecting means T1, the differential pressure detecting means P1 and the second
The detection information of the temperature detecting means T3, and the detection information of the inlet pressure detecting means P2, the outlet pressure detecting means P3, and the outlet temperature detecting means T2 are input to the control means 125. Further, the output MW of the gas turbine 1 is input to the control means 125. Control means 125
From the first flow control valve 120, the second flow control valve 121
And an open / close command is output to the third flow control valve 122.

By opening and closing the first flow control valve 120 according to the detection information of the differential pressure detecting means P1 (according to the differential pressure), the flow of steam to the intermediate pressure steam turbine 112 side is regulated, and the combustor The flow rate of steam flowing through 117 is appropriately controlled. In addition, while opening and closing the second flow control valve 121 according to the detection information of the differential pressure detecting means P1 and the temperature detecting means T1,
By opening and closing the third flow control valve 122 according to the detection information of the second temperature detecting means T3, the amount of steam flowing through the combustor 117 is appropriately controlled while maintaining the appropriate flow rate.
At this time, if the steam temperature rises due to some abnormality even though the amount of steam flowing through the combustor 117 is kept appropriate (when the combustor 117 is not cooled as planned), the detection information of the outlet temperature detecting means T2 The first flow control valve 120, the second flow control valve 121, and the third flow control valve 12
2 is opened and closed, the amount of steam in the steam flow passage 116 is increased, and an excessive rise in the temperature of the steam flowing through the combustor 117 is prevented.

That is, in the control means 125, the combustor 11
7 and the differential pressure corresponding to the required amount of cooling steam is calculated, and the first flow control valve 120 is opened and closed so that the detected value of the differential pressure detecting means P1 becomes the calculated differential pressure. Output command. As a result, the required amount of cooling steam is supplied to the combustor 117. In the control means 125,
The required steam temperature of the gas turbine 101 is calculated, and an opening / closing command is output to the second flow control valve 121 so that the detection value of the temperature detecting means T1 becomes the calculated temperature. At this time, the control unit 125 issues an open / close command to the third flow control valve 122 based on the steam temperature (detection information of the second temperature detection unit T3 and detection information of the temperature detection unit T1) introduced into the steam flow passage 116. The steam temperature in the high-pressure steam flow channel 118 is reduced to a predetermined temperature by appropriately outputting the output of the medium-pressure supply water.

When the flow rate of steam flowing through the combustor 117 increases or decreases due to the temperature control, the first flow control valve 120 is controlled to open and close by the detection information of the differential pressure detecting means P1, and a specified steam flow rate is secured. When the generation of the medium-pressure steam is delayed due to fluctuations or the like, and the absolute flow rate of the steam flowing through the steam flow path 116 becomes insufficient, the detected value of the differential pressure detection means P1 is calculated in priority to the temperature control. The opening and closing of the second flow control valve 121 is controlled so that the pressure becomes high, and the steam flow is secured by introducing high-pressure steam (backup control). That is, the second
An opening / closing command is also output to the flow control valve 121 in the differential pressure control, and an opening command by the temperature control and a high value of the opening command by the differential pressure control are selected and controlled as the opening of the second flow control valve 121. It is supposed to be.

In the above-described steam control apparatus, the steam generated on the medium-pressure drum 106 side having a low temperature and the steam generated on the high-pressure drum 103 having a high temperature are mixed, and the mixed steam flow rate and steam temperature are appropriately controlled. It is introduced into the combustor 117.
Further, in order to perform the mixing optimally, the medium pressure side steam introduction passage 115
The steam flow rate is controlled by opening and closing a first flow control valve 120 provided in the tank, and the steam temperature is controlled by adjusting the high pressure steam flow by opening and closing a second flow control valve 121 provided in the high-pressure steam flow path 118. I have. When the medium pressure steam is insufficient, the second flow control valve 121 is controlled by the backup control.
Is opened and closed to introduce high-pressure steam to secure the flow rate. Therefore, the flow rate of the steam guided to the combustor 117 can be more appropriately controlled without providing an expensive valve device in the steam flow passage 116.

The first flow control valve 1 will be described with reference to FIGS.
The control situation of the 20 and the second flow control valve 121 will be described in detail. FIG. 2 shows a control block configuration of the first flow control valve 120, and FIG. 3 shows a control block configuration of the second flow control valve 121.

As shown in FIG. 2, the calculating means 141 of the control means 125 includes a temperature detecting means T1 and an inlet pressure detecting means P.
2. The detection information of the outlet pressure detecting means P3 and the outlet temperature detecting means T2 is input. Further, the output MW of the gas turbine 101 is input to the conversion operation means 142, and the conversion operation means 14
In 2, the output MW is converted as a required backup steam flow rate and input to the adding means 151. On the other hand, a bias corresponding to the temperature is calculated and added by the function unit 150 based on the detection information of the outlet temperature detecting unit T2, and the added bias value is added to the output MW of the gas turbine 101 by the adding unit 151. Is added. Gas turbine 10
The information obtained by adding the output MW of 1 and the bias value is input to the conversion operation means 142, and the output MW to which the bias value has been added by the conversion operation means 142 is converted as the required cooling steam flow rate, and the operation means 141 Is input to

The bias value is set so that the specifically required cooling steam flow rate increases as the steam temperature detected by the outlet temperature detecting means T2 increases.
That is, as the steam temperature detected by the outlet temperature detecting means T2 becomes higher, the first flow control valve 120 is operated to close and the amount of steam sent to the steam flow passage 116 is controlled to increase. The calculating means 141 converts the input information into a differential pressure equivalent value and outputs it to the adding means 143.
Is input with the detection information of the differential pressure detecting means P1. The adding means 143 obtains the difference between the information on the differential pressure equivalent value from the calculating means 141 and the detection information of the differential pressure detecting means P1, and
At 44, the obtained difference is used as an opening command of the 0-side information.
The 0 side information is sent to the selection means 152. A full closing command (minimum opening, for example, an opening of 3% to 5%) is sent from the commanding unit 153 to the selection unit 152 as one-side information.

The selection means 152 is normally turned off, and turned on when a command is issued from the comparison means 154. That is,
The selection means 152 switches the output command from the 0-side information to the 1-side information by turning on. When the selection means 152 is off, the opening command of the 0-side information (output MW of the gas turbine 101 and steam flow) An opening command according to the condition of the path 116) is output to the first flow control valve 120, and when it is on, an opening command (full closing command) of the one-side information is output to the first flow control valve 120. The detection information of the outlet temperature detecting means T2 is input to the comparing means 154, and the result of the comparing means 154 is
52. The outlet temperature detecting means T2 is provided by the comparing means 154.
If the detected information exceeds the predetermined value (upper limit), an ON signal is output from the comparing means 154 to the selecting means 152, and the selecting means 152 is switched to the opening degree command of the one-side information.

Accordingly, the opening and closing of the first flow control valve 120 is controlled based on the output MW of the gas turbine 101 and the detection information of the state of the steam flow passage 116 so that the steam flow in the steam flow passage 116 becomes a predetermined flow rate. And outlet temperature detecting means T2
When the temperature on the outlet side of the combustor 117 increases in accordance with the steam temperature detected in the step (b), the temperature is controlled to the closed side so that the steam amount in the steam flow passage 116 increases by the temperature rise. Furthermore, the first
When the information detected by the outlet temperature detecting means T2 exceeds a predetermined value (upper limit), the flow control valve 120 is fully closed by a fully closed command (minimum opening command). Is sent to the steam flow path 116 in its entirety.

As shown in FIG. 3, the calculating means 141 of the control device 125 includes a temperature detecting means T1 and an inlet pressure detecting means P.
2. The detection information of the outlet pressure detecting means P3 and the outlet temperature detecting means T2 is input. Further, the output MW of the gas turbine 101 is input to the second conversion calculating means 145, and the output MW is converted into a required backup steam flow rate and input to the adding means 162 in the second conversion calculating means 145.
On the other hand, a bias corresponding to the temperature is calculated and added by the function means 161 based on the detection information of the outlet temperature detecting means T2, and the added bias value is added to the adding means 16 according to the temperature.
In step 2, it is added to the output MW of the gas turbine 101. Information obtained by adding the output MW of the gas turbine 101 and the bias value is input to the calculating means 141, and the second conversion calculating means 145
The output MW to which the bias value has been added is converted as the required cooling steam flow rate and input to the calculating means 141.

Then, the input information is converted into a differential pressure equivalent value by the calculating means 141 and output to the adding means 143. The detecting information of the differential pressure detecting means P1 is input to the adding means 143.
The adding means 143 calculates the difference between the information of the differential pressure equivalent value from the calculating means 141 and the detection information of the differential pressure detecting means P1, and the PI calculating means 144 calculates the obtained difference as an opening degree command.

The bias value is set so that the specifically required cooling steam flow rate increases as the steam temperature detected by the outlet temperature detecting means T2 increases.
That is, as the steam temperature detected by the outlet temperature detecting means T2 increases, the second flow control valve 121 is operated to the open side, and the amount of steam sent from the high-pressure steam flow path 118 to the steam flow path 116 increases. Is controlled as follows.

Therefore, the opening and closing of the second flow control valve 121 is controlled based on the output MW of the gas turbine 101 and the detection information of the state of the steam flow passage 116 so that the steam flow in the steam flow passage 116 becomes a predetermined flow rate. And outlet temperature detecting means T2
When the temperature on the outlet side of the combustor 117 increases in accordance with the steam temperature detected in the step (1), the steam flow in the steam flow path 116 is controlled to be open so that the amount of steam in the steam flow path 116 increases.

For this reason, when the temperature at the outlet side of the combustor 117 increases, the amount of cooling steam increases as the steam temperature detected by the outlet temperature detecting means T2 increases, and the outlet temperature increases. When the detection information of the detection means T2 exceeds a predetermined value (upper limit value), the entire amount of the steam from the intermediate pressure drum 106 is sent to the steam flow path 116, and the amount of the cooling steam is increased. Thus, the combustor 117 is protected even if the cooling steam temperature rises despite the fact that the cooling steam amount is controlled to a predetermined amount.

When the temperature on the outlet side of the combustor 117 becomes high, the first flow control valve 120 and the second flow control valve 1
The opening and closing control of the steam generator 21 is performed by, for example, closing the first flow control valve 120 so that the steam from the medium pressure drum 106 is
6 and when the temperature at the outlet side of the combustor 117 is high even when the first flow control valve 120 is fully closed, the second flow control valve 121 is opened and the amount of steam from the high-pressure steam flow path 118 is opened. Is to be increased. The first flow control valve 1
The state of the opening and closing control of the 20 and the second flow control valve 121 is appropriately set according to the capacity of the equipment and the like, and is implemented in combination with the opening and closing of other control valves so that the securing of the predetermined flow rate and the securing of the predetermined temperature are compatible. You.

[0038]

According to the present invention, there is provided a steam cooling apparatus for a gas turbine, comprising: an exhaust heat recovery boiler for generating steam by exhaust gas from a gas turbine; a steam turbine operated by steam generated by the exhaust heat recovery boiler; A steam introduction passage for introducing steam from the boiler into the steam turbine, a steam cooling passage provided in the steam introduction passage for bypassing steam from the exhaust heat recovery boiler for cooling high-temperature components of the gas turbine, and a heat recovery steam generator Means for detecting steam pressure generated in the steam generator, and controlling the flow rate of steam in the steam introduction path based on the detection information of the generated steam pressure detecting means for adjusting the steam pressure generated in the exhaust heat recovery boiler. A generated steam pressure control valve, a post-cooling steam temperature detecting means provided in a steam cooling passage on a downstream side of the high-temperature component and detecting a steam temperature after cooling the high-temperature component, Control the opening and closing of the generated steam pressure control valve so that the detected value of the generated steam pressure detecting means becomes the set value in order to adjust the flow rate of the steam flowing into the steam cooling path based on the state of the bin, and detect the steam temperature after cooling. Control means for controlling the opening and closing of the generated steam pressure control valve in order to adjust the flow rate of steam flowing into the steam cooling path based on the detection information of the means, without providing an expensive valve device in the steam cooling path. By controlling the generated steam pressure control valve for maintaining the pressure of the steam generated in the exhaust heat recovery boiler in a predetermined state, it is possible to appropriately control the flow rate of the steam guided to the high-temperature parts, and to control the steam temperature after cooling. When the pressure rises, the flow rate of steam guided to the high-temperature component is controlled to be increased so that the high-temperature component can be protected. As a result, it is possible to suppress an increase in the construction cost of the combined cycle power plant and to prevent damage to the high-temperature components.

Further, a steam cooling passage is provided branching from a steam introduction passage from the medium pressure drum to the medium pressure steam turbine, and a medium pressure drum pressure control valve is provided in the steam introduction passage downstream of the branch portion of the steam cooling passage. The generated steam pressure control valve is provided, and the control means controls the medium pressure drum pressure so as to secure the flow rate of the steam cooling path by regulating the flow rate of the steam introduction path based on the detection information of the cooled steam temperature detecting means. Since a function of controlling the opening and closing of the control valve is provided, the steam from the medium pressure drum can be sent to the steam cooling path.

An auxiliary steam introduction passage into which steam from the high-pressure drum is introduced is connected to a steam cooling passage, and an auxiliary steam pressure control valve is provided in the auxiliary steam introduction passage to serve as a generated steam pressure control valve. And a function of controlling the opening and closing of the auxiliary steam pressure control valve so as to control the flow rate of the auxiliary steam introduction path based on the detection information of the post-cooling steam temperature detection means and to secure the flow rate of the steam cooling path. The steam from the high pressure drum can be sent to a steam cooling passage.

The steam cooling passage is connected to an auxiliary steam introduction passage through which steam from the high-pressure drum is introduced. The auxiliary steam introduction passage is connected to an auxiliary fluid flow passage. Auxiliary steam temperature detection means for detecting the temperature of the auxiliary steam is provided in the auxiliary steam introduction path on the flow side, an auxiliary fluid pressure control valve is provided in the auxiliary fluid flow path to serve as a generated steam pressure control valve, and the control means includes cooling. Open / close control of the auxiliary steam pressure control valve is performed to control the flow rate of the auxiliary fluid flow path based on the detection information of the post-steam temperature detection means and the detection information of the auxiliary steam temperature detection means so as to secure the flow rate of the steam cooling path. With the function, the steam from the high-pressure drum and the auxiliary steam can be sent to the steam cooling passage.

A steam cooling passage is provided branching from a steam introduction passage from the medium pressure drum to the medium pressure steam turbine, and an auxiliary steam introduction passage through which steam from the high pressure drum is introduced is connected to the steam cooling passage. A medium-pressure drum pressure control valve is provided in the steam introduction path on the downstream side of the branch of the steam cooling path to provide a generated steam pressure control valve, and an auxiliary steam pressure control valve is provided in the auxiliary steam introduction path to control generated steam pressure. Valve and the control means
The opening and closing of the medium pressure drum pressure control valve is controlled so as to secure the flow rate of the steam cooling path by regulating the flow rate of the steam introduction path based on the detection information of the post-cooling steam temperature detection means, and A function is provided to control the opening and closing of the auxiliary steam pressure control valve so as to secure the flow rate of the steam cooling path by controlling the flow rate of the auxiliary steam introduction path based on the detection information. Steam from the high pressure drum and auxiliary steam can be sent to a steam cooling path.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a cooling system of a combined cycle power plant including a gas turbine steam cooling device according to an embodiment of the present invention.

FIG. 2 is a control block diagram of a generated steam pressure control valve.

FIG. 3 is a control block diagram of a generated steam pressure control valve.

FIG. 4 is a schematic configuration diagram showing a cooling system of a combined cycle power plant equipped with a conventional gas turbine steam cooling device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Gas turbine 102 Exhaust heat recovery boiler 103 High pressure drum 104 1st high pressure superheater 105 2nd high pressure superheater 106 Medium pressure drum 107 Medium pressure superheater 108 Reheater 109 High pressure steam introduction channel 110 High pressure steam turbine 112 Medium pressure steam turbine 113 Low-pressure steam turbine 114 Condenser 115 Medium-pressure steam introduction path 116 Steam flow path 117 Combustor 118 High-pressure steam flow path 119 Auxiliary fluid flow path 120 First flow control valve 121 Second flow control valve 122 Third flow control valve 125 Control means 141 Calculation means 142 Conversion calculation means 143, 151, 162 Addition means 144 PI calculation means 145 Second conversion calculation means 150, 161 Function means 152 Selection means 153 Command means 154 Comparison means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Kita 1-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo F-term in Takasago Works, Mitsubishi Heavy Industries, Ltd. (reference) 3G081 BA02 BA11 BB00 BC07 BD00 DA06 DA23

Claims (5)

[Claims] An exhaust heat recovery boiler that generates steam by exhaust gas of a gas turbine, a steam turbine that operates by using the steam generated by the exhaust heat recovery boiler, and a steam that introduces steam from the exhaust heat recovery boiler into the steam turbine An introduction path, a steam cooling path provided in the steam introduction path to bypass steam from the exhaust heat recovery boiler for cooling high-temperature components of the gas turbine, and a generated steam pressure for detecting a steam pressure generated in the exhaust heat recovery boiler. Detecting means, a generated steam pressure control valve for controlling the flow rate of steam in the steam introduction path based on the detected information of the generated steam pressure detecting means for adjusting the steam pressure generated in the exhaust heat recovery boiler, After-cooling steam temperature detecting means provided in the steam cooling passage on the flow side to detect the steam temperature after cooling the high-temperature components, and flows into the steam cooling passage based on the state of the gas turbine. Control the opening and closing of the generated steam pressure control valve so that the detected value of the generated steam pressure detecting means becomes the set value in order to adjust the steam flow rate to be applied to the steam cooling passage based on the detection information of the cooled steam temperature detecting means. Control means for controlling the opening and closing of the generated steam pressure control valve in order to adjust the flow rate of the flowing steam. 2. A steam cooling passage branched from a steam introduction passage from an intermediate-pressure drum to an intermediate-pressure steam turbine is provided, wherein the steam cooling passage is provided downstream of a branch portion of the steam cooling passage. A pressure drum pressure control valve is provided as a generated steam pressure control valve, and the control means regulates the flow rate of the steam introduction path based on the detection information of the post-cooling steam temperature detection means to secure the flow rate of the steam cooling path. A steam turbine cooling device for a gas turbine, further comprising a function of controlling opening and closing of a medium pressure drum pressure control valve. 3. The generated steam pressure control valve according to claim 1, wherein the auxiliary steam introduction passage into which steam from the high-pressure drum is introduced is connected to the steam cooling passage, and the auxiliary steam introduction passage is provided with an auxiliary steam pressure control valve. The control means has a function of controlling the flow rate of the auxiliary steam introduction path based on the detection information of the post-cooling steam temperature detection means and controlling the opening and closing of the auxiliary steam pressure control valve so as to secure the flow rate of the steam cooling path. A steam cooling device for a gas turbine, which is provided. 4. The auxiliary steam introduction path according to claim 1, wherein an auxiliary steam introduction path through which steam from the high-pressure drum is introduced is connected to the steam cooling path, and an auxiliary fluid flow path is connected to the auxiliary steam introduction path. Auxiliary steam temperature detection means for detecting the temperature of the auxiliary steam is provided in the auxiliary steam introduction passage on the downstream side of the junction of the above, and an auxiliary fluid pressure control valve is provided in the auxiliary fluid flow path to generate a generated steam pressure control valve. The means includes an auxiliary steam pressure control valve that controls the flow rate of the auxiliary fluid flow path based on the detection information of the post-cooling steam temperature detection means and the detection information of the auxiliary steam temperature detection means to secure the flow rate of the steam cooling path. A steam cooling device for a gas turbine, comprising a function of controlling the opening and closing of a gas turbine. 5. The steam turbine according to claim 1, further comprising a steam cooling passage branched from a steam introduction passage from the medium pressure drum to the medium pressure steam turbine, and an auxiliary steam introduction passage through which steam from the high pressure drum is introduced. A medium pressure drum pressure control valve is provided in the steam introduction path on the downstream side of the branch of the steam cooling path to form a generated steam pressure control valve, and an auxiliary steam pressure control valve is provided in the auxiliary steam introduction path. The control means includes a medium-pressure drum pressure control valve that regulates the flow rate of the steam introduction path based on the detection information of the after-cooling steam temperature detection means and secures the flow rate of the steam cooling path. The function of controlling the opening and closing of the auxiliary steam pressure control valve so as to secure the flow rate of the steam cooling path by controlling the flow rate of the auxiliary steam introduction path based on the detection information of the after-cooling steam temperature detecting means. Provided Steam cooling apparatus for a gas turbine, characterized in that.