JP2915885B1 - Gas turbine combined cycle system - Google Patents

Abstract

A gas turbine combined cycle power generation system incorporating a steam-cooled gas turbine, which is capable of more appropriate and stable steam cooling without impairing controllability of cooling steam. It is an object to provide a system. SOLUTION: In a steam-cooled gas turbine combined power generation system using exhaust gas of a high-pressure turbine as gas turbine cooling steam, a gas spray combined power generation system is configured by arranging a water spray device or the like in a cooling steam supply pipe,
When using high-pressure exhaust gas as cooling steam for a gas turbine, the outlet steam temperature of the high-temperature cooled part of the gas turbine is uniquely determined with respect to the cooling steam flow rate by controlling the supply temperature of the cooling steam with a water spray device to be constant. The control form has been simplified to improve the controllability of cooling steam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combined cycle system incorporating a steam-cooled gas turbine.

[0002]

2. Description of the Related Art A steam-cooled gas turbine combined cycle system is a system characterized by using high-temperature exhaust gas from a gas turbine as a heat source of a boiler and cooling high-temperature components inside the gas turbine with steam. A description will be given based on FIG .

[0003] Reference numeral 1 denotes a high-pressure turbine, which is axially connected to the intermediate-pressure turbine 5, the low-pressure turbine 19, and the steam turbine generator 14, and forms a power generation unit using the steam turbine in the combined power generation system.

[0004] Reference numeral 2 denotes a gas turbine unit, which communicates with a combustor 11 via a transition piece and a gas turbine compressor 12.
And a gas turbine generator 13 to form a power generation unit using a gas turbine in the combined power generation system.

[0005] Reference numeral 3 denotes an exhaust heat recovery boiler, a reheater 4 and a superheater 1.
0, including an evaporator, an economizer, and the like, not shown, which are heated by the gas turbine exhaust gas 18 of the gas turbine section 2 to generate main steam 7, high-pressure reheat steam 9 and the like, and recover the exhaust heat. The final exhaust from the boiler 3 is configured to be released to the atmosphere by a chimney 15.

Here, since the gas turbine section 2 needs to cool its high-temperature portion, a moving blade cooled portion 2a and a stationary blade cooled portion 2b are formed in the gas turbine main body, and a transition piece portion of the combustor 11 is formed. The cooling part 2c of the tail pipe of the combustor is formed at the bottom.

The high-pressure turbine exhaust 8 discharged from the high-pressure turbine 1 as a refrigerant for cooling these high-temperature portions
Is used by partially bypassing the transition pipe cooling steam control valve 6a,
Stator blade cooling steam control valve 6b and moving blade cooling steam control valve 6c
Through the combustor transition piece cooled portion 2c and the stationary blade cooled portion 2b
And the moving blade cooling portion 2a.

The remainder of the high-pressure turbine exhaust 8 is as follows:
The reheater 4 communicates with the reheater 4 via the reheater inlet control valve 6d, merges with the cooling steam from the moving blade cooled portion 2a in the middle of the reheater 4, and further has the stationary blade cooled portion 2b and The cooling steam from the combustor tail pipe cooled portion 2c is combined with the cooling steam and supplied to the intermediate pressure turbine 5 via the intermediate pressure turbine inlet control valve 6e.

As described above, in the ordinary steam-cooled gas turbine combined cycle system, a part of the exhaust gas of the high-pressure turbine 1 is branched and supplied to the gas turbine section 2 to be cooled by the combustor transition piece exposed to the high-temperature gas. The part 2c, the stationary blade cooled part 2b, and the moving blade cooled part 2a are cooled.

[0010] The steam which has been heated to a high temperature as a result of the cooling of each of the parts to be cooled is recovered at the intermediate portion of the reheater 4 of the exhaust heat recovery boiler 3 or at the outlet thereof, and supplied to the intermediate pressure turbine 5. Inflates and does work.

When the cooling steam is supplied to the gas turbine from the steam cycle, it is preferable to control the amount of the cooling steam in accordance with the heat load of the high temperature part in order to keep the metal temperature of the high temperature part of the gas turbine below the limit value.

Therefore, the gas turbine steam cooling system includes:
A number of flow control valves (tail pipe cooling steam control valve 6a, stationary blade cooling steam control valve 6
b, bucket cooling steam control valve 6c, reheater inlet control valve 6d,
A medium-pressure turbine inlet control valve 6e) is installed, and the gas turbine high-temperature cooled part (the moving blade cooled part 2a, the stationary blade cooled part 2)
b, The steam flow rate control is performed so that the steam temperature at the outlet of the combustor transition piece cooled portion 2c) is always below the limit value.

In the steam-cooled gas turbine combined power generation system, the high-pressure turbine exhaust 8 is often most suitable as the gas turbine cooling steam in terms of pressure and temperature conditions.

When supplying cooling steam from the path of the high-pressure turbine exhaust 8 to the gas turbine, a part of the high-pressure turbine exhaust 8 is used by branching and bypassing, and the rest is an exhaust heat recovery boiler 3 using the gas turbine exhaust as a heat source. And reheat.

This is because, when excessive steam is supplied to the gas turbine unit 2 for cooling the gas turbine, the outlet steam temperature after cooling the gas turbine unit 2 falls below the optimum temperature as the inlet steam of the intermediate-pressure turbine 5. In order to reduce the efficiency of the cycle, only a necessary and sufficient amount is supplied to the gas turbine, and the surplus is separately heated by the exhaust heat recovery boiler 3, so that the gas turbine is mixed at the inlet of the intermediate pressure turbine 5 where both are mixed. This is because the optimum steam temperature can be maintained.

Further, since the heat load of the gas turbine high-temperature cooled part changes every moment according to the gas turbine load, a control valve for constantly supplying an appropriate amount of steam to the gas turbine part 2 is required. In order to play a role, a reheater inlet control valve 6d is installed at the reheat steam inlet of the reheater 4.

That is, when the load on the gas turbine rises, the reheater inlet control valve 6d operates in the closing direction to reduce the amount of steam supplied to the reheater 4, and instead, the steam bypassed to the gas turbine. By increasing the amount, it is possible to cope with an increase in the heat load of the gas turbine high temperature cooled part.

A control valve (a transition cooling steam control valve 6a, a transition pipe cooling valve 6a) for controlling the steam flow rate for each system is provided upstream of the transition piece of the combustor 11 and the moving and stationary blades of the gas turbine.
A stationary blade cooling steam control valve 6b, a moving blade cooling steam control valve 6c, a reheater inlet control valve 6d, and a medium pressure turbine inlet control valve 6e) are installed, and an optimum steam amount is supplied to each high temperature cooled part. The desired cooling is performed.

However, with the above-described control that has been conventionally considered, the gas turbine cooling steam outlet temperature control may not be performed as desired by the following mechanism.

Assume that the load of a plant currently operating with a certain gas turbine load is increased. This plant throttles the reheater inlet control valve according to the procedure described above, but at that time, the steam flow in the gas turbine steam cooling system increases, and the boiler reheater including the reheater inlet control valve is also used. Although the steam flow rate decreases in the system, the pressure loss of the entire system increases due to an increase in the throttle loss of the reheater inlet control valve.

On the other hand, since the inlet pressure of the intermediate-pressure turbine is constant, the exhaust pressure of the high-pressure turbine, which is determined by accumulating the pressure losses of the respective systems, rises. As a result, the high-pressure turbine exhaust temperature rises.

This phenomenon is a serious problem when the high-pressure turbine exhaust is used as a cooling steam source, and the result of the increase in the steam flow rate is offset by the increase in the supply steam temperature.

Accordingly, the problem that the steam temperature at the outlet of the gas turbine high-temperature cooled part cannot be effectively controlled only by controlling the steam cooling flow rate becomes apparent.

Although not shown again as another embodiment different from the above, in order to increase the amount of cooling steam, in addition to the configuration described in FIG.
There is a case where a path for connecting the medium-pressure steam to the supply side of the gas turbine cooling steam is provided to increase the amount of the cooling steam.

In such a configuration, the drum pressure of the medium pressure system is determined depending on the pressure of the gas turbine cooling steam supply system.

In the case described above, the reheater 4
In order to throttle the reheater inlet control valve 6d on the inlet side of the gas turbine, the gas turbine cooling steam supply pressure rises, and the medium pressure drum pressure rises accordingly.

Then, the saturation temperature of the medium-pressure evaporator (not shown) increases, the temperature difference from the gas temperature decreases, and the amount of evaporation in the evaporator decreases.

As a result, the amount of cooling steam of the gas turbine decreases, so that the temperature of the steam at the gas turbine high-temperature cooled part outlet increases.

As described above, the throttle operation of the reheater inlet control valve for increasing the gas turbine cooling steam causes an increase in the exhaust pressure of the high-pressure turbine and a decrease in the amount of the medium-pressure steam. Offset.

This phenomenon is particularly remarkable in a moving blade steam cooling system which requires a large cooling steam flow rate because a large effective load cannot be obtained due to a high heat load and structural restrictions.

[0031] In addition, blades for a high speed rotation body, the cooling steam is present pumping losses incurred to traffic a rotating system and a stationary system, rapidly increases Re this is with the increase of the steam flow rate Therefore, there is a special situation that the pressure loss of the rotor blade system is greatly increased.

FIG . 5 shows an example of a change in the steam temperature at the moving blade outlet when the steam flow rate of the moving blade is increased or decreased.

When the steam flow rate is equal to or less than Go, the pressure loss of the entire gas turbine steam cooling system is controlled by the stationary blade system arranged in parallel with the moving blade system.

On the other hand, when the steam flow rate is equal to or higher than Go, the pressure loss of the moving blade system increases and becomes larger than that of the stationary blade system, and the moving blade system pressure loss is dominant.

In the region where the pressure loss of the moving blade system is dominant, the exhaust pressure and the temperature of the high-pressure turbine increase with the increase of the moving blade steam flow, and the moving blade inlet steam temperature increases.

Also, the amount of medium-pressure steam that merges with the moving blade cooling steam, lowers the steam temperature at the moving blade inlet, and increases the flow rate decreases, and the proportion of the relatively high-temperature high-pressure turbine exhaust increases. You can see that he is doing it.

This is also one of the factors for raising the moving blade inlet steam temperature. As a result, even if the temperature of the moving blade cooling steam is increased or decreased by the control valve, the moving blade outlet temperature does not change so much, which indicates that it is difficult to control the outlet temperature using the cooling steam.

FIG . 6 schematically shows a gas turbine steam cooling system. When attention is paid to the moving blades of the rotating system, a moving blade pressure loss occurs in the moving blade itself, and a pumping loss (PL) occurs upstream and downstream of the moving blade. ) Occurs.

In FIG. 7 , the rotor blade steam loss corresponding to the piping pressure loss, the pressure loss at the rotor blade steam side control valve, the pumping loss, the pressure loss of the rotor blade itself, and the sum of these pressure losses The pressure loss of the moving blade system total is shown in breakdown.

That is, in the region where the pressure loss of the moving blade system where the steam flow rate is equal to or more than Go is dominant, both the increase in the pressure loss of the moving blade due to the increase in the steam flow rate and the increase in the pressure loss due to the pumping loss overlap. It can be seen that the pressure loss of the entire wing system has increased rapidly.

[0041]

As described above, in the conventional gas turbine combined power generation system using this kind of steam as a cooling medium, there are some problems inherent in the gas turbine combined power generation system. More appropriate ones are required and never stop.

The present invention is based on this point of view and solves the above-mentioned various problems in the prior art to enable more stable steam cooling without impairing the controllability of cooling steam. It is an object of the present invention to provide a combined gas turbine power generation system.

[0043]

The present invention solves the above-mentioned problems.
In a steam-cooled gas turbine combined power generation system that uses the exhaust of a high-pressure turbine as gas turbine cooling steam, a superheat spray control device of a superheat reducer that controls the temperature of the main steam is used to solve the problem. Input information and supply temperature information of the gas turbine cooling steam,
The present invention provides a gas turbine combined cycle system that controls the operation of a superheater spray in accordance with such information. In the present invention, as described above, the overheating of the superheat reducer is performed based on the main steam temperature information and the gas turbine cooling steam supply temperature information. Since the operation of the superheater spray is controlled in the spray control device, and as a result, the temperature of the main steam is controlled, the desired control can be performed without the necessity of providing a special cooler for the gas turbine cooling steam. is there.

Further, according to the present invention, in a steam-cooled gas turbine combined power generation system using exhaust gas of a high-pressure turbine as gas turbine cooling steam, a medium-pressure steam pipe is connected to a cooling steam supply system, and the medium-pressure steam pipe is controlled. Installing a valve and controlling the saturation temperature of the medium-pressure evaporator by adjusting its opening,
The present invention provides a gas turbine combined power generation system in which the temperature of the cooling steam is controlled by changing the amount of evaporation of the medium-pressure evaporator. By supplying pressurized steam and thereby controlling the supply temperature of the cooling steam to a constant value, the outlet steam temperature of the high-temperature cooled portion of the gas turbine can be almost uniquely determined with respect to the cooling steam flow rate. It is possible to greatly improve the performance.

Also, the present invention provides a gas turbine combined power generation system in which the medium-pressure steam piping is connected from either the outlet of the medium-pressure superheater or the middle thereof, and in the present invention, supplies the gas into the cooling steam of the gas turbine. Not limited to using saturated steam that has exited the medium pressure evaporator as in the above invention as the medium pressure steam,
After leaving the medium-pressure evaporator, it is further heated through a medium-pressure superheater and supplied from the outlet or the middle of the medium-pressure superheater, and the type of medium-pressure steam used, The shape is given a range to achieve the desired effect of temperature reduction.

Further, in the present invention, in a steam-cooled gas turbine combined power generation system utilizing exhaust gas of a high-pressure turbine as gas turbine cooling steam, a medium-pressure steam pipe is connected to a cooling steam supply system and a high-pressure turbine communicated with the high-pressure turbine. A high-pressure steam control valve is placed in the main steam pipe, the opening of the high-pressure steam control valve is adjusted to change the saturation pressure of the high-pressure evaporator, and the medium pressure is indirectly changed by changing the amount of evaporation of the high-pressure evaporator. The present invention provides a gas turbine combined power generation system in which the temperature of the cooling steam is controlled by changing the amount of evaporation of an evaporator. In the present invention, the medium-pressure steam is supplied into the cooling steam in the same manner as in the above invention. When controlling the steam temperature, the saturation pressure of the high-pressure evaporator is changed by the operation of the high-pressure steam control valve upstream of the introduction of the medium-pressure steam, thereby indirectly evaporating the medium-pressure evaporator. It is for controlling the temperature of the cooling steam by changing the one in which was set to implement a qualified temperature control by opening and closing operation of the simple valve.

Further, the present invention provides a gas turbine combined power generation system in which the intermediate-pressure steam supplied to the cooling steam supply system is supplied from either the outlet of the intermediate-pressure superheater or the middle thereof. The opening degree of the high-pressure steam control valve arranged in the pipe is adjusted, and as a result, the medium-pressure steam controlled as a result exits the medium-pressure evaporator and is further heated through the medium-pressure superheater. The steam is supplied from the outlet of the pressure superheater or from the middle thereof, and the kind and form of the medium-pressure steam to be used is varied to achieve the intended temperature-reducing effect.

[0048]

Figure a first embodiment of DESCRIPTION OF THE INVENTION The present invention will now
1 will be described. FIG. 1 shows a steam-cooled gas turbine combined cycle system according to the present embodiment in which a main steam temperature is adjusted by a superheater and a superheat reducer of an exhaust heat recovery boiler to control a supply temperature of gas turbine cooling steam. 1 shows a schematic configuration.

[0049] Note that although the equipment and the same portion of the conventional described above are given the same reference numerals in the figures, and redundant description will be mainly described a configuration in which certain features of the present embodiment is omitted.

In this embodiment, reference numeral 50 denotes a superheat reducer, which is a temperature detector 51a for detecting a main steam temperature T1 from the superheater 10 and a temperature detector for detecting a cooling steam temperature T2 of a gas turbine cooling steam supply pipe 54. The superheated spray water control valve 5 is controlled by the superheater spray control device 51 according to a command from the heater 51b
2 to supply an appropriate amount of spray water 53.

That is, the main steam temperature T1 and the cooling steam temperature T2
For example, when the supply temperature of the gas turbine cooling steam is high, the main steam temperature is lowered by injecting spray water into the superheater 10, and the temperature of the gas turbine cooling steam is reduced indirectly. ing.

In this embodiment, the gas turbine cooling steam is not directly temperature-controlled, but the main steam temperature is reduced by using the existing superheater 10 and superheat reducing device 50 in the exhaust heat recovery boiler 3. The turbine cooling steam temperature can be controlled to be substantially constant.

In the present embodiment, by controlling the supply temperature of the gas turbine cooling steam to be substantially constant in this manner, the high-temperature cooled portion (the moving blade cooled portion 2a, The outlet steam temperature of the blade cooled portion 2b and the combustor transition piece cooled portion 2c) can be uniquely determined by the flow rate of the cooling steam.

This means that the temperature control mechanism in the present embodiment is simple and clear, and controllability is greatly improved.

Further, according to the present embodiment, as described above, existing equipment is sufficient, and there is no need to separately install a cooler for cooling gas turbine cooling steam, so that the system can be configured simply. In addition, there is no problem that the installation of the cooler causes the drain to enter the gas turbine or raise the pressure loss of the system.

Further, if the drum saturated steam contained in a part of the exhaust heat recovery boiler 3 is used as a cooling medium of the superheater 10 and the superheat reducer 50, a deposit inside the high temperature cooled portion of the gas turbine may be concerned. It is also possible to avoid contamination with impurities.

Next, a second embodiment of the present invention will be described with reference to FIG . Fig. 2 shows a book that lowers the temperature of the gas turbine cooling steam by mixing the medium pressure steam into the gas turbine cooling steam supply pipe and controlling the amount of medium pressure steam generated by changing the saturation pressure of the medium pressure evaporator. 1 shows a schematic configuration of a steam-cooled gas turbine combined cycle system according to an embodiment.

The above-described conventional apparatus and the first embodiment
The same parts as those in the form states denoted by the same reference numerals in the figures, and redundant description will be mainly described a configuration in which certain features of the present embodiment is omitted.

That is, in this embodiment, reference numeral 60 denotes a medium-pressure evaporator. The medium-pressure steam 62 generated by the medium-pressure evaporator 60 is adjusted by a medium-pressure steam control valve 61 to control the gas turbine cooling steam supply pipe. 54 to control the gas turbine cooling steam supply temperature.

In other words, the medium-pressure steam 62 supplied from the medium-pressure evaporator 60 is connected to the gas turbine cooling steam supply system via the medium-pressure steam control valve 61, By changing the pressure, the drum pressure of the medium-pressure evaporator 60 changes, and the amount of evaporation of the medium-pressure steam 62 can be controlled. And this medium pressure steam 6
By controlling 0, the supply temperature of the gas turbine cooling steam can be controlled to be substantially constant.

In this embodiment, by controlling the supply temperature of the gas turbine cooling steam to be substantially constant in this manner, the high-temperature cooling of the gas turbine unit 2 is performed in the same manner as in the other embodiments described above. The outlet steam temperature of the sections (the moving blade cooled section 2a, the stationary blade cooled section 2b, and the combustor transition piece cooled section 2c) can be uniquely determined by the flow rate of the cooling steam.

This is not corrected, and the mechanism of temperature control in the present embodiment is simple and clear.
Controllability will be greatly improved.

In the present embodiment, the supply temperature of the cooling steam is reduced by mixing the cooling steam with the low-temperature medium-pressure steam, and a control valve is provided at the outlet of the medium-pressure steam to provide a medium-pressure drum. The supply temperature of the gas turbine cooling steam is controlled by changing the pressure to adjust the evaporation amount of the medium-pressure steam.

During normal operation, the medium pressure steam control valve is designed to be slightly throttled, and if the supply temperature of the cooling steam is likely to rise due to some factors, the medium pressure steam control valve is opened to open the medium pressure steam control valve. It is preferable to increase the evaporation amount of the gas turbine, thereby lowering the gas turbine cooling steam supply temperature. In other words, such a contrivance enables more appropriate temperature control.

In the above description, the medium-pressure steam 62 to be supplied to the gas turbine cooling steam supply pipe 54 is obtained from the medium-pressure evaporator 60. A similar control is possible with the steam superheated.

Therefore, the medium-pressure evaporator 60 described in the present embodiment may be appropriately replaced with the medium-pressure superheater 60. Moreover, in the case where this is a medium-pressure superheater 60, it is not limited to passing through all the paths and supplying from the outlet,
This includes supply from the middle of the intermediate-pressure superheater 60, whereby the type and form of the medium-pressure steam to be supplied is given a wide range so that the intended temperature-reducing effect can be achieved. Things.

Next, a third embodiment of the present invention will be described with reference to FIG . FIG. 3 shows a book in which medium-pressure steam is mixed into the gas turbine cooling steam supply pipe, and the gas turbine cooling steam temperature is reduced by controlling the amount of medium-pressure steam generated by changing the saturation pressure of the high-pressure evaporator. 1 shows a schematic configuration of a steam-cooled gas turbine combined cycle system according to an embodiment.

It should be noted that the conventional device described above and the
The same parts as those of the first and second embodiments are denoted by the same reference numerals in the drawings, and the overlapping description will be omitted, and the description will focus on the characteristic configuration in the present embodiment.

That is, in the present embodiment, reference numeral 70 denotes a high-pressure steam control valve, which is provided in the supply path of the main steam 7 from the superheater 10 in the exhaust heat recovery boiler 3 to the high-pressure turbine 1. The saturation pressure of the high-pressure evaporator (not shown) is changed by controlling the control valve 70, and as a result, the amount of medium-pressure steam generated in the downstream medium-pressure evaporator is adjusted.

Under such a configuration, for example, when lowering the temperature of the gas turbine cooling steam, if the high-pressure steam control valve 70 is throttled, the saturation pressure and temperature of the high-pressure drum (not shown) increase, and the heating source The temperature difference from the gas side becomes smaller, and the amount of high-pressure evaporation decreases.

As a result, the amount of heat exchanged by the high-pressure evaporator decreases, so that the outlet gas temperature of the high-pressure evaporator increases, and the medium-pressure evaporator installed downstream of the high-pressure evaporator in the exhaust heat recovery boiler 3 The inlet gas temperature at 60 also increases. As a result, the amount of evaporation in the medium-pressure evaporator 60 increases, and a sufficient amount of the medium-pressure steam 62 can be supplied to the gas turbine cooling steam, and the supply temperature of the gas turbine cooling steam decreases.

As in the case of the second embodiment, the medium-pressure steam 62 is not limited to the one that has come out of the medium-pressure evaporator 60. It can be heated further through an omitted medium-pressure superheater and supplied from the outlet or the middle of the medium-pressure superheater. Application.

[0073] Incidentally, including this embodiment, the said embodiment
In the first and second embodiments, the cooling steam is described as a high-temperature portion to be cooled of the gas turbine unit 2 for the moving blade cooled portion 2a, the stationary blade cooled portion 2b, and the combustor transition piece cooled portion 2c. However, the high-temperature part to be cooled has been identified as the most delicate gas turbine blade system in terms of mechanical structure and cooling structure from the characteristics of the structure and function of the gas turbine, and appropriate cooling has been performed. It can also provide a great cooling effect.

Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0075]

As described above, according to the present invention, in a steam-cooled gas turbine combined cycle system utilizing exhaust gas of a high-pressure turbine as gas turbine cooling steam,
The temperature information of the main steam and the supply temperature information of the gas turbine cooling steam are input to the superheat spray control device of the superheat reducer that controls the temperature of the main steam, and the operation of the superheater spray is controlled according to the information. Therefore, the operation of the superheater spray is controlled by the superheat spray control device of the superheat reducer based on the temperature information of the main steam and the supply temperature information of the gas turbine cooling steam as described above. As a result, it is possible to obtain a system in which the temperature of the main steam is controlled, so that the desired control can be performed without the necessity of newly providing a cooler for the gas turbine cooling steam. .

According to the second aspect of the present invention, there is provided a steam-cooled gas turbine combined cycle system utilizing exhaust gas of a high-pressure turbine as gas turbine cooling steam.
A medium-pressure steam pipe is connected to the cooling steam supply system, and a control valve is installed in the medium-pressure steam pipe to control the saturation temperature of the medium-pressure evaporator by adjusting the opening, and the evaporation amount of the medium-pressure evaporator is controlled. Since the gas turbine combined power generation system is configured so as to control the temperature of the cooling steam by changing, the medium pressure steam is supplied to the cooling steam supply system by changing the evaporation amount of the medium pressure evaporator, whereby the cooling is performed. By controlling the steam supply temperature to be constant, the outlet steam temperature of the high-temperature cooled part of the gas turbine can be almost uniquely determined with respect to the cooling steam flow rate, so that the controllability of the cooling steam is greatly improved. The system as described above was obtained.

According to the third aspect of the present invention, the intermediate-pressure steam pipe is connected to either the outlet of the intermediate-pressure superheater or from the middle thereof to form a gas turbine combined power generation system. The medium-pressure steam supplied to the cooling steam of the gas turbine is not limited to using the saturated steam that has exited the medium-pressure evaporator as in the above invention. In order to achieve the desired temperature reduction effect, the type and form of the medium-pressure steam to be used can be varied by further heating the medium and supplying it from the outlet or the middle of the medium-pressure superheater. It was done.

According to the fourth aspect of the present invention, there is provided a steam-cooled gas turbine combined cycle system utilizing exhaust gas from a high-pressure turbine as gas turbine cooling steam.
The medium-pressure steam pipe is connected to the cooling steam supply system, and the high-pressure steam control valve is arranged in the high-pressure main steam pipe connected to the high-pressure turbine. And the temperature of the cooling steam is controlled by indirectly changing the evaporation amount of the medium-pressure evaporator by changing the evaporation amount of the high-pressure evaporator to constitute the gas turbine combined power generation system. Therefore, when the medium-pressure steam is supplied into the cooling steam and the temperature of the cooling steam is controlled in the same manner as the above invention, the saturation pressure of the high-pressure evaporator is increased by operating the high-pressure steam control valve upstream of the introduction of the medium-pressure steam. A system that controls the temperature of the cooling steam by indirectly changing the evaporation amount of the medium-pressure evaporator and thereby performing appropriate temperature control by a simple valve opening / closing operation. It is.

According to the fifth aspect of the present invention, the intermediate-pressure steam supplied to the cooling-steam supply system is supplied from one of the outlet and the middle of the intermediate-pressure superheater. Since the system is configured, adjust the opening of the high-pressure steam control valve located in the high-pressure main steam pipe,
The medium-pressure steam controlled as a result exits the medium-pressure evaporator, is further heated through the medium-pressure superheater, and is supplied from the outlet or the middle of the medium-pressure superheater. A system that achieves a desired temperature reduction effect by giving a variety of types and forms of the pressurized steam could be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a steam-cooled gas turbine combined cycle system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a steam-cooled gas turbine combined cycle system according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a schematic configuration of a steam-cooled gas turbine combined cycle system according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a schematic configuration of a conventional steam-cooled gas turbine combined cycle system.

FIG. 5 is an explanatory diagram illustrating an example of a change in a moving blade outlet steam temperature when the steam flow rate of the moving blade is increased or decreased in the steam-cooled gas turbine combined cycle system.

FIG. 6 is an explanatory diagram schematically showing a gas turbine steam cooling system in the steam-cooled gas turbine combined cycle system.

FIG. 7 is an explanatory diagram showing pressure loss of a rotor blade system in the steam-cooled gas turbine combined cycle system, which is divided into parts.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-pressure turbine 2 Gas turbine part 2a Cooled part of moving blade 2b Cooled part of stationary blade 2c Cooled part of combustor transition piece 3 Exhaust heat recovery boiler 4 Reheater 5 Medium pressure turbine 6a Transition pipe cooling steam control valve 6b Static blade Cooling steam control valve 6c Rotor blade cooling steam control valve 6d Reheater inlet control valve 6e Medium pressure turbine inlet control valve 7 Main steam 8 High pressure turbine exhaust 9 High pressure reheat steam 10 Superheater 11 Combustor 12 Gas turbine compressor 13 Gas Turbine generator 14 Steam turbine generator 15 Chimney 16 Atmosphere 17 Fuel 18 Gas turbine exhaust gas 19 Low pressure turbine 50 Superheat reducer 51 Superheater spray control device 51a Temperature detector 51b Temperature detector 52 Superheated spray water control valve 53 Spray water 54 Gas turbine cooling steam supply pipe 60 Medium pressure evaporator 61 Medium pressure steam control valve 62 Medium pressure steam 70 High pressure steam Damping valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01K 23/10 F02C 6/00 F02C 7/18

Claims (5)

(57) [Claims] 1. In a steam-cooled gas turbine combined cycle system utilizing exhaust gas from a high-pressure turbine as gas turbine cooling steam, the superheat spray control device of a superheat reducer for controlling the temperature of the main steam includes information on the temperature of the main steam and the temperature. A gas turbine combined power generation system characterized in that supply temperature information of gas turbine cooling steam is input and operation of a superheater spray is controlled in accordance with the information. 2. In a steam-cooled gas turbine combined cycle system using exhaust gas from a high-pressure turbine as gas turbine cooling steam, a medium-pressure steam pipe is connected to a cooling steam supply system, and a control valve is installed in the medium-pressure steam pipe. Controlling the saturation temperature of the medium-pressure evaporator by adjusting the opening thereof, and controlling the temperature of the cooling steam by changing the amount of evaporation of the medium-pressure evaporator. . 3. claims, characterized in that it has contacted one of the outlet or midway of the medium-pressure steam pipe medium pressure superheater
Item 3. A gas turbine combined cycle system according to Item 2 . 4. A steam-cooled gas turbine combined cycle system utilizing exhaust gas from a high-pressure turbine as gas turbine cooling steam, wherein a medium-pressure steam pipe is connected to a cooling steam supply system and is connected to the high-pressure turbine. A high-pressure steam control valve is placed in the high-pressure steam control valve, and the opening of the high-pressure steam control valve is adjusted to change the saturation pressure of the high-pressure evaporator. A gas turbine combined cycle system, wherein the temperature of the cooling steam is controlled by changing the amount of evaporation. 5. The gas turbine combined cycle system according to claim 4 , wherein the intermediate-pressure steam supplied to the cooling-steam supply system is supplied from any one of an outlet and a middle of the intermediate-pressure superheater.