JPH11311132A - Steam-cooling gas turbine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust cooling steam to a proper temperature for the purpose of cooling, without entailing any corrosion or the like in a cooling system, and to make it so as to be providable for the end by supplying both of gas turbine blade cooling steam and combustor tail pipe cooling steam to the blade and the tail pipe after they are adjusted to reduce their temperature by a heat exchange with fuel and a cooling device of a cooler or the like, in this combined cycle power plant. SOLUTION: High pressure exhaust of a high pressure turbine 7 available as cooling steam is heat transferred by a fuel heater 18 and, after it is cooled through a cooling device capable of adjusting a cooling temperature, the high pressure exhaust is made so as to be fed to each cooling part of the blade of a gas turbine 4 and the tail pipe of a combustor 6, constituting a steam cooling gas turbine system, and a cooling steam supplying temperature is made possible to be set to such a temperature as necessary even in any operating conditions, while the occurrence of any nonconformity such as a drop in heat transfer rate at a cooling passage and corrosion or the like is eliminated, and thus the gas turbine system is largely conducible to an improvement of efficiency in a combined cycle power plant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined cycle power plant, in which heat of gas turbine blade cooling steam and combustor tail pipe cooling steam is reduced by a heat exchange with fuel and a cooling device such as a cooler, and then the blade is cooled. And a steam-cooled gas turbine system adapted to supply to a transition piece.

[0002]

2. Description of the Related Art An outline of a conventional steam-cooled gas turbine will be described with reference to FIG.

[0003] Conventional steam-cooled gas turbines perform blade cooling using steam directly from the high pressure turbine outlet,
After that, it is a system to recover to medium pressure turbine,
The combustor transition piece was cooled by the outlet air of the compressor.

That is, in FIG. 2, reference numeral 01 denotes a gas turbine device, 02 denotes an exhaust heat recovery boiler, 7 denotes a high-pressure turbine, 8 denotes a medium-pressure turbine, and 9 denotes a low-pressure turbine. After compressing the ambient air to a predetermined pressure, the air pressurized by the compressor 5 is mixed with fuel adjusted to a predetermined temperature at the inlet of the turbine 4 and burned in a combustor 6.

[0005] In the turbine 4, the high-temperature and high-pressure combustion gas generated in the combustor 6 is expanded to generate an output, and the power
To generate electricity. Exhaust gas after work is exhaust gas duct 1.
0 to the exhaust heat recovery boiler 02.

[0006] The stationary blades and the moving blades of the turbine 4 are cooled by receiving high-pressure exhaust as cooling steam from the outlet of the high-pressure turbine 7 through the blade cooling steam supply pipe 11, and cooled by the cooling. The steam is supplied to the inlet of the intermediate pressure turbine 8 via the blade cooling steam recovery pipe 12.

In the exhaust heat recovery boiler 02, the high-pressure steam generated in the high-pressure drum 3 is guided to the high-pressure turbine 7 by the high-pressure steam pipe 13, and expands in the high-pressure turbine 7 to generate an output.

The outlet steam of the high-pressure turbine 7 is guided as cooling steam to the turbine stationary blades and the moving blades of the gas turbine 01 by the blade cooling steam pipe 11, and to the reheater 24 of the exhaust heat recovery boiler 02. Divided into things.

The medium-pressure steam generated in the medium-pressure drum 2 is mixed with the remaining high-pressure exhaust of the branch of the cooling steam from the outlet steam of the high-pressure turbine 7 and then supplied to the reheater 24. After being heated in the intermediate pressure turbine 8, it is mixed with the blade cooling steam guided by the blade cooling steam recovery pipe 12.
Supplied to

In the intermediate pressure turbine 8, these steams expand to obtain a predetermined output. The medium-pressure exhaust, which is the outlet steam of the medium-pressure turbine 8, is mixed with the low-pressure steam generated in the low-pressure drum 1 and supplied through the low-pressure steam pipe 15,
It is supplied to the low-pressure turbine 9 to obtain a predetermined output.

The low-pressure exhaust discharged from the low-pressure turbine 9 is condensed by a condenser 21, pressurized to a predetermined pressure by a pressurizing pump 22, and then supplied to an exhaust heat recovery boiler 02 by a water supply pipe 23. .

[0012]

As described above, in the conventional steam-cooled gas turbine system, the cooling steam for cooling the turbine stationary blades and the moving blades is cooled by directly supplying high-pressure exhaust gas from the high-pressure turbine 7. Because it is offered to
When the inlet temperature of the gas turbine, the opening degree of the inlet guide vanes, the atmospheric temperature, or the like changes, the outlet temperature of the high-pressure turbine 7 changes accordingly, and the turbine blade cooling steam temperature changes.

The change in the turbine blade cooling steam temperature leads to a simultaneous change in the turbine blade and metal temperatures. Particularly, at a partial load, the cooling steam temperature tends to increase, and the turbine blades may creep. However, there is a problem that the property arises.

As an attempt to control the supply temperature of the cooling steam to cope with the higher temperature of the cooling steam, it is conceivable to supply the spray water into the cooling steam. In this case, the spray water is mixed with the steam. During the evaporation and evaporation process, impurities in the spray water are generated in the cooling steam, and the impurities may adhere to the cooling passages of the steam cooling blades, causing corrosion of the steam cooling blades.

In addition to the corrosion problem, impurities adhering to the cooling passage of the steam cooling blade lower the heat transfer coefficient of the cooling steam passage, so that the blade metal temperature increases and the blade may creep. is there.

The corrosion of the cooling passages of the steam cooling blades causes the wall thickness of the blades to be thin, causing cracks, and the cooling steam may leak into the turbine 4 of the gas turbine 01.
In addition, since it is known that this steam leakage reduces the combined efficiency, it is an important matter to avoid the inclusion of corrosion-causing impurities in the cooling steam.

Under such a background, the present invention solves the problems in the conventional apparatus of this type and the conventional apparatus of this type, and eliminates the problem of corrosion or the like of the high-pressure exhaust used as cooling steam. It is an object of the present invention to provide a material which can be cooled to a suitable temperature.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a combination of a gas turbine plant and a steam turbine plant to generate steam for driving a steam turbine by utilizing exhaust heat of the gas turbine. In a combined cycle power plant equipped with an exhaust heat recovery boiler, high-pressure turbine high-pressure exhaust used as gas turbine blade cooling steam and combustor transition piece cooling steam is exchanged with gas turbine fuel through a fuel heater, and then the cooling temperature is reduced. A steam-cooled gas turbine system is provided that is cooled through an adjustable cooling device and then supplied to a cooling section of a gas turbine blade and a combustor transition piece.

According to the present invention, the high-pressure turbine high-pressure exhaust gas is cooled by the gas turbine fuel through the fuel heater before being supplied to the high-temperature portion of the gas turbine as the gas turbine blade cooling steam and the combustor transition piece cooling steam. The heat is recovered at the same time, and then cooled by a cooling device capable of adjusting the cooling temperature, and then subjected to the intended cooling, so that the temperature can be adjusted to a required temperature according to the condition of the high-temperature portion and supplied. Since the high-temperature portion can be cooled at an appropriate temperature, and there is no risk of impurities being mixed into the cooling steam in this process, there is no problem such as a decrease in heat transfer coefficient of the cooling passage and occurrence of corrosion. This greatly contributes to improving the efficiency of the combined cycle power plant.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

The same parts as those of the prior art described above are denoted by the same reference numerals in the drawings, and redundant description will be omitted, and the characteristic features of the present embodiment will be mainly described.

Reference numeral 18 denotes a fuel heater, which is a blade cooling steam supply pipe 11, a transition piece cooling steam supply pipe 16, and a combustor 6 for guiding high pressure exhaust gas of the high pressure turbine 7 to a high temperature portion of the gas turbine device 01.
Includes a path to supply fuel to

Reference numeral 19 denotes a cooler, which includes a turbine 4 and a combustor 6.
At the upstream position, the blade cooling steam supply pipe 11 and the transition piece cooling steam supply pipe 16 that have exited the fuel heater 18 are taken in.
The cooling temperature can be adjusted by a fan 26 driven by the fan 5.

In this embodiment configured as described above, part of the high-pressure exhaust discharged from the outlet of the high-pressure turbine 7 is used as cooling steam by the blade cooling steam supply pipe 11 and the transition piece cooling steam supply pipe 16. Guided through the fuel heater 18,
While heating the fuel of the gas turbine, the heat exchange itself is performed so as to be cooled, and then the blade cooling steam supply pipe 11 and the transition piece cooling steam supply pipe 16 are supplied to the cooler 19, and the cooler 19 cools the gas to a predetermined temperature. Decrease the temperature.

In the cooler 19, the number of rotations of the fan 26 is adjusted by controlling and adjusting the number of rotations of the motor 25 disposed facing the outside by a suitable control device (not shown). Cooling steam supply pipe 11
And the temperature after the temperature of the steam supplied from the transition pipe cooling steam supply pipe 16 is reduced.

That is, in the present embodiment, the cooler 19 is employed as the cooling device as described above, and the motor 25,
By operating the cooling temperature of the cooler 19 so as to be adjustable by the fan 26, it is possible to control and adjust the cooling steam supply temperature to a desired temperature during the rated operation and the partial load operation of the gas turbine device 01. Things.

Further, in the present embodiment, as described above, in adjusting the temperature of the cooling steam, the method of supplying the spray water to the cooling steam supply path is not used, and the cooling steam supply temperature is reduced by heat exchange in the cooler. Because it is warm
There is no risk of impurities being mixed into the cooling steam.

In the present embodiment, the cooling steam supply temperature can be controlled to a predetermined temperature during the rated operation and the partial load of the gas turbine as described above, so that the turbine 4 It is expected that the reliability of the stationary blade and the moving blade will be ensured, and that the combined efficiency will be improved by heating the fuel.

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

[0030]

As described above, according to the present invention, a combined gas turbine plant and a steam turbine plant are provided with an exhaust heat recovery boiler for generating steam for driving a steam turbine by utilizing exhaust heat of the gas turbine. In a cycle power plant, high-pressure turbine high-pressure exhaust used as gas turbine blade cooling steam and combustor tail tube cooling steam is exchanged with gas turbine fuel through a fuel heater, and then cooled through a cooling device whose cooling temperature is adjustable. After that, the steam-cooled gas turbine system was configured to supply the gas turbine blades and the combustor transition piece to the cooling section. High-pressure turbine high-pressure exhaust supplied to the gas turbine Cooling and heat recovery, and then cooled by a cooling device with adjustable cooling temperature, and then subjected to the intended cooling, so that the combustor transition piece cooling and the gas turbine turbine blade cooling steam supply temperature can be adjusted to any operating conditions. Temperature can be set to the required temperature, so that the temperature of the combustor transition piece and the turbine blade metal of the gas turbine can be controlled within the allowable temperature and cooled at an appropriate temperature. Since there is no risk of impurities being mixed, there is no problem such as a decrease in the heat transfer coefficient of the cooling passage and the occurrence of corrosion, and this has greatly contributed to the improvement of the efficiency of the combined cycle power plant.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing a system of a conventional steam-cooled gas turbine system.

[Explanation of symbols]

 Reference Signs List 01 Gas turbine device 02 Exhaust heat recovery boiler 3 High pressure drum 4 Turbine 5 Compressor 6 Combustor 7 High pressure turbine 8 Medium pressure turbine 9 Low pressure turbine 10 Exhaust gas duct 11 Blade cooling steam supply pipe 12 Blade cooling steam recovery pipe 13 High pressure steam pipe 16 Transition pipe cooling steam supply pipe 18 fuel heater 19 cooler 20 generator 21 condenser 22 pressurization pump 23 water supply pipe 24 reheater 25 motor 26 fan

Claims (1)

[Claims] 1. A combined cycle power plant comprising a gas turbine plant and a steam turbine plant and having an exhaust heat recovery boiler for generating steam for driving the steam turbine by using exhaust heat of the gas turbine. The high-pressure turbine, which is used as steam for cooling the combustor transition piece, exchanges heat with gas turbine fuel through a fuel heater, and then cools through a cooling device capable of adjusting the cooling temperature. A steam-cooled gas turbine system, characterized in that the steam is supplied to a cooling unit.