JP2941748B2 - Gas turbine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas turbine constituting a combined cycle plant (hereinafter, simply referred to as "plant"), which is capable of generating high temperature, high temperature generated by combustion of high pressure air discharged from a compressor and supplied fuel. The present invention relates to a gas turbine cooling device that cools moving blades and stationary blades that operate in high-pressure combustion gas, and in particular, applies high-pressure air used for cooling a rotating rotor and moving blades (hereinafter referred to as rotor cooling). Cooling from the high temperature state discharged from the compressor to the temperature of the rotor cooling air, reducing the amount of high-pressure air required for cooling the rotor, reducing the load on the compressor, and improving the unit efficiency of the gas turbine With the cooling heat recovered by cooling the high-pressure air, the temperature of the bleed air used for cooling the vanes is heated to the vane cooling air temperature,
The present invention relates to a gas turbine cooling device capable of improving the thermal efficiency of an entire plant by further reducing the load on a compressor that is increased by bleed air.

[0002]

2. Description of the Related Art In a gas turbine blade operating in a high-temperature, high-pressure combustion gas, high-temperature, high-pressure compressed air discharged from a compressor driven by a gas turbine is moved through a flow passage provided in a rotor. Introduced inside or at the root of the rotor, the rotor, the rotor including the disk and the root of the blade are cooled by the rotor, and the air is extracted from the middle stage of the compressor,
Compared to the high-temperature, high-pressure compressed air discharged from the compressor, by adopting a gas turbine cooling device that cools the stationary blades with low-temperature, low-pressure compressed air, these heats become high. By reducing the load, these gas turbine blades can be made of a material having a low resistance to high temperatures, thereby achieving cost reduction and achieving a highly reliable and long-life device.

[0003] After cooling the portion to be cooled, the cooling air used for such cooling is normally released into the combustion gas from the tip of the blade or from the front or rear edge side, and is recovered by cooling. Energy is not particularly recovered to improve the efficiency of the plant, and the adoption of such a gas turbine cooling device provides the above-mentioned advantages, but is disadvantageous in terms of thermal efficiency. Become.

Further, in rotor cooling for cooling a moving blade or the like that becomes high in temperature, a high-pressure air discharged from a compressor, which has a temperature of 400 ° C. or more, is cooled by an external cooler. It has been considered that the rotor is cooled to a temperature and the rotor is cooled with a small amount of cooling air to further improve the efficiency. That is, when the rotor is cooled with a small amount of cooling air, the amount of high-pressure air required for cooling the rotor can be reduced, and the load required for the compressor driven by the gas turbine is reduced. To be able to make that much smaller,
It is possible to increase the unit efficiency of the gas turbine.

However, when viewed as a whole plant including a gas turbine as a part, the cooling heat recovered by the external cooler that cools the high-pressure air for cooling the rotor is simply radiated to the outside. Therefore, it is not collected and returned to the plant to be used to contribute to the increase in power and the like generated in the plant, but the heat dissipated from the external cooler improves the efficiency of the gas turbine alone, for example. Even if it becomes, when converted to the overall plant efficiency, the same as the above-described gas turbine cooling device that performs rotor cooling while maintaining the high-temperature, high-pressure compressed air discharged from the compressor described above. In addition, there is a problem that the thermal efficiency of the entire plant is reduced, and the efficiency is reduced at least by the amount of heat dissipated.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages of the conventional gas turbine cooling system. First, in order to improve the efficiency of a single gas turbine, high-pressure air discharged from a compressor is first used. To cool the rotor and to supply it for cooling the rotor, to reduce the supply of high-pressure air required for cooling the rotor, to improve the efficiency of the gas turbine itself, and to cool the high-pressure air for cooling the rotor. By using the cooling heat recovered when heating the bleed air from the compressor that cools the stationary vanes, the load loss of the compressor due to bleed is reduced, and the gas turbine is partly configured. To provide a gas turbine cooling system that can improve not only the efficiency of the gas turbine alone but also the overall efficiency of the plant by improving the thermal efficiency of the entire plant. The title.

[0007]

For this reason, the gas turbine cooling device of the present invention has the following means. Low-temperature, low-pressure bleed air that is bled from the middle stage of the compressor and supplied to the vanes, and cooled to the vanes, is discharged from the compressor,
By exchanging heat with high-temperature, high-pressure discharge air supplied from the blade root portion or the blade root portion to the rotor blade through a flow passage formed in the rotor to cool the rotor and the rotor blade with the rotor, a high-pressure The heat retained by the air is recovered to the bleed air, the bleed air is heated to the stationary blade cooling air temperature designed for the stationary blade, and supplied to the stationary blade, and the rotor can be cooled with a small volume of high-pressure air. In this way, a heat recovery device that cools the high-pressure air to the rotor cooling air temperature and supplies it to the rotor and the rotor blades is provided.

The rotor cooling air temperature and the stationary blade cooling air temperature are determined based on the capacity and performance of the gas turbine.
It is uniquely determined in the design. Further, the heat recovery device is preferably provided so as to be able to adjust the temperature of the bleed air for each bleeding stage for cooling the stationary blade, respectively, and the temperature adjustment of the bleed air is performed by using water injection. Is also good.

According to the gas turbine cooling device of the present invention, the rotor can be cooled by a small volume of high-pressure air by the above-described means.
It is possible to reduce the discharge amount of high-pressure air that needs to be discharged more than necessary for combustion in the gas turbine, reduce the driving force of the compressor driven by the gas turbine, and reduce the power generated by the gas turbine. Can be increased. As a result, the power of the gas turbine that drives the compressor while generating power is improved.

In addition, the heat recovered by cooling the high-temperature, high-pressure high-pressure air that cools the rotor and the rotor blades by the heat recovery device is radiated to the outside like a conventional rotor cooling device. Without, low temperature that cools the stationary blade,
Since it is recovered by low-pressure extracted air and used to heat the extracted air that cools the stationary blades, the thermal efficiency of the plant that includes the gas turbine as a part can be improved considerably by the recovered cooling heat. it can.

That is, the bleed air extracted from the compressor to cool the stationary blades is a lower temperature, lower pressure bleed air,
In other words, the compressed air from the lower pressure bleeding stage of the compressor is sufficient, and the driving force of the compressor driven by the gas turbine can be reduced accordingly, and the gas turbine can generate extra power. In addition, the cooling heat recovered by the heat recovery device can further improve the thermal efficiency of the plant.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotor cooling device according to the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a gas turbine showing a first embodiment of a rotor cooling device of the present invention and a diagram showing a flow of cooling air, and FIG.
It is a perspective view which shows the detail of the heat exchanger shown in FIG.

As shown in FIG. 1, 400 discharged from a compressor 1 into a vehicle interior 3 provided so as to enclose the periphery of a combustor 2.
The high-pressure air 4 having a high temperature of ℃ is extracted from the compartment 3 and introduced into the high-temperature heat exchanger 5 as a heat recovery device, and exchanges heat with the high-pressure extraction 11 extracted from the high-pressure extraction hole 8 of the compressor 1. And the temperature is lowered to 380 ° C.
Spill out of.

The second stage stationary blade 1 is bleed from the high pressure bleed hole 8.
In the present embodiment, the high-pressure bleed air 11 that cools the fourth stage 4 happens to be a stationary blade cooling air temperature 35 that cools the second stage stationary blade 14.
Since the high-pressure bleed air 11 having the same temperature as 0 ° C. is bled, after the temperature of the high-pressure bleed air 11 is heated by the high-pressure air 4 in the high-temperature heat exchanger 5, it is optimal for cooling the two-stage stationary blade 14. Pure water 25 is injected from a water tank 24 by means of a device 23 to provide a water injection amount provided with a water amount control valve 22 so that the stationary blade cooling air temperature becomes 350 ° C.
I try to keep the temperature down.

This is because the rotor cooling device of the present embodiment is applied to an existing gas turbine. However, when a new gas turbine is designed, the high-pressure bleed holes 8 need to be slightly lower in pressure. If it is provided on the side, and the temperature of the high-pressure bleed air 11 is lowered to perform the bleed, the thermal efficiency can be further improved.

However, even when the temperature of the high-pressure bleed air 11 is set lower than in the case of the present embodiment, the water injection devices 23 etc.
It is preferable that the temperature of the bleed air such as 1 is provided so as to be able to be accurately adjusted to the rotor cooling air temperature and the vane cooling air temperature determined by the design.

The high-pressure air 4 flowing out of the high-temperature heat exchanger 45 is introduced into a medium-temperature heat exchanger 6 as a heat recovery device, and the medium-pressure bleed air 12 extracted from a medium-pressure bleed hole 9 of the compressor.
Pressure exchange with heat exchanged with 250 ° C
2 is 320 which is the vane cooling air temperature of the third stage vane 15
The temperature is lowered to 350 ° C. by heating the mixture to 350 ° C., and flows out of the intermediate temperature heat exchanger 6.

High pressure air 4 whose temperature has dropped to 350 ° C.
Is similarly introduced into the low-temperature heat exchanger 7 as a heat recovery device, and the low-temperature heat exchanger 7 exchanges heat with the low-pressure bleed air 13 extracted from the low-pressure bleed hole 10 of the compressor 1 to reduce the pressure to 150 ° C. By heating the bleed air 13 to 300 ° C., which is the stationary blade cooling air temperature of the fourth stage stationary blade 16, the high-pressure air 4
The temperature is reduced to 250 ° C., which is the rotor cooling air temperature determined by the design.

The high-pressure air 4 whose temperature has been lowered to the rotor cooling air temperature passes through a high-pressure air introduction pipe 26 and passes through the rotor 21.
Through the flow path provided in the axial direction of the first stage,
Second stage rotor blade 18, third stage rotor blade 19, and fourth stage rotor blade 20
In this order, the blades are introduced into the air passages provided inside the respective moving blades from the blade root portions to cool the moving blades 17 to 20 including the rotor 21, the disk, and the blade root portion.
From the leading edge side, the tip side, and the trailing edge side of 0, each is released into the combustion gas.

The high-temperature heat exchanger 5, the medium-temperature heat exchanger 6, and the low-temperature heat exchanger 7 as the heat recovery device are configured separately as shown in FIG. However, it is also possible to provide an integrated unit. Heat recovery device 27
The heat transfer unit 30 is sandwiched between end plates 29 erected on the base plate 28 and is tightened with a tightening bolt 31 to be integrated into a single unit.
And the low-temperature heat exchanger 7.

A high-pressure air inlet 32 and a high-pressure air outlet 33 for introducing or discharging the high-pressure air 4 shown in FIG. 1 are provided on the same side surface, and bleed air such as the high-pressure bleed air 11 is introduced or discharged. The bleed air inlet 34 and the bleed air outlet 35 to be provided are also provided on the same side surface, and heat transfer by the heat transfer unit 30 is performed to perform heat exchange of Air-Ti-Air. For this reason, even if a leak should occur due to aging or the like, it is safe, and the direct heat exchange method between the high-pressure air 4 and the bleed air 11 to 13 is adopted. In addition, the heat recovery device 27 itself can be designed to be compact.

As described above, in the gas turbine cooling device of the present invention, the cooling of the gas turbine blades is performed by the transfer of heat energy in the gas turbine cycle, and the cooling is performed outside the plant system as in the conventional gas turbine cooling device. Since the recovered heat is not radiated to the plant, the overall efficiency of the plant does not decrease, and the plant can be economically superior.

[0023]

As described above, according to the gas turbine cooling device of the present invention, low-temperature, low-pressure bleed air for cooling the stationary blades and the compressed air discharged from the compressor, and the rotor and the rotor blades are rotated by the rotor. By exchanging heat with high-temperature, high-pressure discharge air that has been cooled, the heat of the high-pressure air is recovered in advance as extracted air, and the recovered heat cools the extracted air with the stationary blades. A heat recovery device is provided that heats the rotor to a temperature and cools the rotor with a small volume of high-pressure air cooled to the rotor cooling air temperature by heating the extracted air.

Thus, the supplied high-pressure air is cooled for cooling the rotor, and the rotor can be cooled by a small amount of high-pressure air. In addition, the excess discharge amount of high-pressure air that needs to be discharged can be reduced, and the driving force of the compressor driven by the gas turbine can be reduced.
Thereby, the unit efficiency of the gas turbine is improved.

Further, the heat recovered by the heat recovery device cools the stationary blade without being radiated to the outside as in the conventional rotor cooling device. Since it is used for heating, the thermal efficiency of the plant including the gas turbine as a part can be improved at least by the recovered cooling heat. That is, low-pressure, medium-pressure, low-temperature, which is bled from the compressor and cools the vanes
By directly exchanging heat between the high-pressure bleed air and the high-temperature high-pressure air that cools the rotor of the rotor and the like, high-pressure air that performs rotor cooling in a high-temperature state without heat radiation loss outside the gas turbine cycle system The temperature can be lowered to the design temperature, the amount of high-pressure air for cooling can be reduced, and the thermal efficiency as a combined cycle plant can be increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a gas turbine showing a first embodiment of a rotor cooling device of the present invention and a diagram showing a flow of cooling air,

FIG. 2 is a perspective view showing details of a heat exchanger (heat recovery device) shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 compressor 2 combustor 3 cabin 4 high-pressure air 5 high-temperature heat exchanger as heat recovery device 6 medium-temperature heat exchanger as heat recovery device 7 low-temperature heat exchanger as heat recovery device 8 high-pressure bleed hole 9 medium-pressure extraction Pores 10 Low pressure extraction hole 11 High pressure extraction 12 Medium pressure extraction 13 Low pressure extraction 14 Second stage stationary blade 15 Third stage stationary blade 16 Fourth stage stationary blade 17 First stage moving blade 18 Second stage moving blade 19 Third stage moving blade 20 Fourth stage moving Wings 21 Rotor 22 Water volume control valve 23 Water injection device 24 Water tank 25 Pure water 26 High pressure air introduction pipe 27 Heat recovery device 28 Base plate 29 End plate 30 Heat transfer unit 31 Tightening bolt

Claims (1)

(57) [Claims] 1. A gas turbine cooling device which cools high-pressure air discharged from a compressor and cools a rotor and a rotor blade to a rotor cooling air temperature, and performs rotor cooling with a small volume of the high-pressure air. In the method, heat is exchanged between the high-pressure air and the low-temperature bleed air that is bled from the compressor and supplied to the vanes, and cools the vanes. And a heat recovery device for heating the stator blade cooling air temperature and supplying it to the stator blades, cooling the high-pressure air to a rotor cooling air temperature and supplying the rotor and the rotor blades. A gas turbine cooling device.