JPH08277726A - Gas turbine installation - Google Patents

Abstract

PURPOSE: To provide a gas turbine plant having high efficiency in which steam cooling can be achieved in its comparatively simple structure as well as to minimize the consumption of cooling steam so as to improve plant efficiency in a gas turbine installation which cools a turbine stationary and moving blades using steam and recovers the steam. CONSTITUTION: This installation is provided with a first cooling system 12 which supplies steam to a stationary blade 20a so as to cool it and recovers the steam, and a second cooling system 15 which cools moving blades 30a, 30b using the recovered steam and recovers the steam. This installation is constituted by providing cooling means to cool the steam recovered in the first cooling system 12 between the first cooling system 12 and the second cooling system 15. Hereby, the consumption quantity of cooling steam on the turbine stationary blade 20a and the moving blades 30a, 30b can be restricted to the minimum, and also high temperature steam after it cools the moving blades 30a, 30b can be recovered so that plant efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine for cooling the stationary blades and moving blades of a turbine using steam, and more particularly to a gas turbine facility with improved plant efficiency.

[0002]

2. Description of the Related Art To improve the efficiency of a gas turbine, it is effective to improve the element performance and raise the temperature of the working gas.
The rise in working gas temperature is due to the development of heat resistant materials and high temperature element members,
In particular, it is based on the technology for cooling the turbine static / moving blades, but at present the material development requires a long period of time even though the working gas temperature exceeds the heat-resistant temperature of the blades. It is important to strengthen the cooling of the static and moving blades. Conventionally, in a gas turbine, the air extracted from the compressor is used as a cooling medium, and after cooling the inside of the turbine blade, most of the air is used for film cooling of the outer surface of the blade or is discharged from the blade directly into the working gas. are doing. Therefore, the entire amount of air compressed by the compressor does not work effectively from the first stage to the final stage of the turbine and consumes compression power, and the temperature of the working gas decreases or mixes due to dilution of the cooling air at a relatively low temperature. However, there was a drawback that the output of the turbine was reduced and the effect could not be fully exhibited, such as a mixing loss with the working gas. Further, at the high temperature of the level currently being promoted, the consumption amount of the cooling air is excessively increased, and the merit in the cycle due to the high temperature is impaired, and conversely the plant efficiency is lowered.

Therefore, as a method of effectively cooling a turbine blade with a small amount of cooling medium, steam having a heat transfer coefficient larger than that of air and a larger specific heat than that of air is used as a cooling medium due to differences in physical quantities such as viscosity coefficient and Prandtl number. It has been proposed to improve the cooling performance by using the steam turbine, and to collect the steam after cooling the turbine blades into the working gas without recovering the steam into the working gas to perform the work. As a device related to this type, for example, JP-A-5-163960 can be cited.In a combined cycle power plant utilizing exhaust heat from a gas turbine, after cooling a high temperature cooled part with superheated steam, The superheated steam is collected in a steam turbine. However, the specific cooling system in the turbine section is not shown. By the way, in a recovery-type gas turbine with an air cooling system, a configuration has been proposed in which the cooling air used for cooling the turbine section is returned to a combustor or the like.
Plant efficiency is higher when steam is used.

[0004]

SUMMARY OF THE INVENTION In order to effectively realize a gas turbine facility for steam-cooling turbine blades according to the purpose, not only steam cooling of stationary vanes, which is a stationary body and relatively easy to construct, is required. In order to prevent the consumption of cooling air from increasing, steam cooling is also essential for cooling the rotor blades that are rotating bodies. For that purpose, in order to improve the efficiency of the entire plant as in the case of using air as the cooling medium, it is necessary to reduce the consumption of steam as much as possible and to recover the steam to contribute effectively to the work. In addition, for the supply or recovery of steam to the rotor blades that are rotating bodies, there is a great improvement in overall plant efficiency of gas turbine equipment that uses steam as the cooling medium, such as reducing leakage at the seals. It becomes an issue. The object of the present invention is made in view of the above circumstances, and aims to improve efficiency as compared with the conventional air cooling system, and to provide an optimum gas turbine facility for a gas turbine by a steam cooling system. It is in.

[0005]

In order to achieve the above object, in the gas turbine equipment of the present invention, the superheated steam generated in the steam generating equipment is led to the stationary blades of the turbine by the supply pipe, and is introduced into the stationary blades. When the superheated steam passes through the provided cooling passage, heat is exchanged to cool the vanes, and the first cooling system that recovers the superheated steam by the recovery pipe and the superheated steam that is recovered by the first cooling system It is supplied to the moving blades of the turbine, which is a rotating body, through the piping leading to the shaft end and the steam supply path formed inside the turbine, and when superheated steam passes through the cooling passage provided inside the moving blade, heat is exchanged to the moving blades. After cooling
It is configured by a cooling system having a second cooling system that collects the steam from a shaft end of the gas turbine by a steam pipe through a steam recovery path formed inside the turbine.

Further, a cooling means for cooling the superheated steam recovered from the first cooling system is provided between the first cooling system and the second cooling system. If a water spray device is provided in the steam pipe as the cooling means, the superheated steam and the water directly exchange heat, so that the superheated steam can be cooled with a relatively small amount of water supply. Further, a water-cooled heat exchanger is provided as the cooling means, and the superheated steam recovered in the first cooling system is passed through the heat exchanger.
Indirect heat exchange can prevent the generation of mist in the steam.

[0007]

In the gas turbine equipment constructed as described above, when the gas turbine is operated, superheated steam having a larger heat transfer coefficient and specific heat than that of air is generated in the first cooling system and the second cooling system, respectively. The temperature rises due to heat exchange inside the stationary blades and moving blades. Since the heated superheated steam is not discharged into the working gas but is recovered by the steam turbine or the like in the plant, the plant efficiency can be improved.

On the other hand, the superheated steam is recovered at a lower pressure than when it is supplied to the first cooling system and supplied to the second cooling system because of the pressure loss generated in the first cooling system. It acts to reduce the pressure difference with respect to the cause of leakage at a seal portion or the like in a certain second cooling system.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a configuration diagram of a gas turbine facility of this embodiment and a partial cross-sectional view of a turbine portion. In order to make the present invention easier to understand, the case where it is applied to a two-stage turbine is shown. The gas turbine 5 mainly includes a turbine 1, a compressor 3 that is connected to the turbine 1 to obtain compressed air for combustion, and a combustor 2 that generates high-temperature high-pressure gas.

At the radially outer end of the stationary blade 20a of the turbine 1, there are a superheated steam supply port 21 and a discharge port 22. The supply port 21 and the discharge port 22 are hollow inside the stationary blade 20a. The cooling passages 23 provided are in communication with each other. A steam pipe 10 for supplying superheated steam to the supply port 21 and a discharge port 2
A steam pipe 11 for recovering superheated steam from 2 is installed, and a first cooling system 12 is configured.

On the other hand, inside the moving blades 30a and 30b, hollow cooling passages 33a and 33b are provided, respectively, and superheated steam supply ports 31a and discharge ports are provided at their radially inner ends. 32a or a supply port 31b and a discharge port 32b are provided, and the supply port and the discharge port communicate with each other through cooling passages. Then, in order to supply the superheated steam to the supply ports 31a and 31b of the moving blades 30a and 30b, a steam flow path including a steam pipe extending from the outside of the turbine 1 to the shaft end of the turbine 1 and a supply path provided inside the rotor of the turbine 13, and a steam flow composed of a recovery path for recovering the superheated steam from the exhaust ports 32a, 32b of the moving blades and extending to the shaft end of the turbine 1 provided inside the rotor and a steam pipe extending from the shaft end to the outside of the turbine 1. A passage (recovery pipe) 14 is formed and a second cooling system 15 is configured. The steam pipe 11 of the first cooling system 12 is connected to the steam passage 1 of the second cooling system 15.
3 communicating with the first cooling system 12 and the second cooling system 1
5 is equipped with a water-cooled heat exchanger 16.

In the present embodiment thus constructed,
The compressed air discharged from the compressor 3 along with the operation of the gas turbine is guided to the combustor 2 and burned with the fuel, and the burned high-temperature and high-pressure working gas is used for the first stage stationary blades 20a, moving blades 30a, Second stage stationary blade 20b, moving blade 30
When passing through b, the rotating shaft of the turbine (not shown) is rotated. The generator 4 connected to the rotating shaft of the turbine is driven to generate electric power. At this time, the working gas flows into the stationary blade 20a at a pressure of about 20ata and an average temperature of about 1400 to 1500 ° C, but this temperature exceeds the allowable temperature of the material for ensuring the reliability of the turbine blade. , Need to cool the wings. Therefore, the pressure generated by the steam generator (not shown) is 30at.
a. Superheated steam having a temperature of about 250 ° C. is supplied to the steam pipe 10 of the first cooling system 12. The supplied superheated steam reaches the supply port 21 of the stationary blade 20a through the steam pipe 10. When the superheated steam passes through the cooling passage 23 having the supply port 21 and the discharge port 22 communicating with each other, the inner wall surface of the stationary blade 20a is forcibly convectively cooled to remove the heat of the stationary blade 20a and rise in temperature. . In addition, when passing through the steam pipe 10 and the stationary blade 2
Due to the pressure loss that occurs when cooling 0a, the steam pipe 10
It is recovered from the discharge port 22 to the steam pipe 11 at a pressure lower than that when supplied to the steam pipe 11. The superheated steam recovered in the steam pipe 11 is indirectly cooled with the water supplied to the heat exchanger 16 by a water-cooled heat exchanger 16 provided between the first cooling system 12 and the second cooling system 15. And the temperature is returned to about 250 ° C., and the pressure is further reduced by pressure loss during this period. The superheated steam that has passed through the heat exchanger 16 is guided to the steam flow path 13 that is composed of the steam piping of the second cooling system 15 and the supply path inside the rotor that are in communication with each other, and the supply path that is configured by branching the moving path 30a. And 30b toward the supply ports 31a and 31b. When the superheated steam branched in the supply path passes through the cooling passages 33a and 33b having the supply port 31a and the discharge port 32a, and the supply port 31b and the discharge port 32b at the ends, the inner wall surfaces of the moving blades 30a and 30b. Is cooled by forced convection and heat exchange to raise the temperature to about 400 ° C, and the outlet
After passing through 32a, 32b, on a recovery path extending to the shaft end of the turbine 1 provided inside the rotor, and passing through a steam flow path 14 for recovery through a steam pipe extending from the shaft end to the outside of the turbine 1, It is recovered by a steam turbine (not shown).

In the process of supplying and recovering steam to the stationary blades and moving blades of the turbine described above, since the cooling system is configured in series, the number of steam pipes is small and the turbine has a relatively simple structure. The steam cooling of the stationary blades and the moving blades is achieved, and the plant efficiency can be improved by collecting the superheated steam in the steam turbine. In addition, against the occurrence of steam leakage at the seal part of the second cooling system that is responsible for supplying and recovering superheated steam to the rotor blades that are rotating bodies, for example, the conventional cooling medium supply method by air cooling is used. Similarly, compared to the case where the cooling system is configured in parallel and the same pressure is supplied to the stationary blades and the moving blades, the difference at the leakage point is equal to the decrease in the supply pressure due to the pressure loss generated in the first cooling system. The pressure is reduced and the amount of leakage can be reduced. Therefore, it is possible to reduce the amount of superheated steam generated in the steam generation facility, improve plant efficiency, and prevent an increase in the amount of makeup water for generating steam. Furthermore, when the cooling system is configured in parallel and the cooling medium is supplied to the stationary blade and the moving blade under the same temperature condition, the stationary blade 20a having a higher working gas temperature cools the moving blades 30a and 30b. Also requires a large amount of steam flow. In this case, the total amount of steam consumed is the sum of the amounts supplied to the stationary blades and the moving blades, whereas in the present embodiment, the steam flow rate required to cool the stationary blades 20a is set to the first cooling system 1.
If it is supplied to 2, the moving blades 30a, 30b, which inevitably require a smaller flow rate than the stationary blades, will be able to obtain a sufficient flow rate. Since it can be cooled, the production amount of superheated steam can be reduced and the plant efficiency can be improved.

In this embodiment, the steam recovered in the first cooling system 12 is cooled using the water-cooling type heat exchanger 16.
Of course, other means may be used for cooling,
For example, as another means, if you use a water spray,
Since it can be cooled by exchanging heat with superheated steam, the amount of cooling water can be reduced.

Further, in the present embodiment, the case where the invention is applied to a two-stage turbine is explained. Although only the stationary vanes 20a of the first stage on the stationary side are cooled by superheated steam, the stationary vanes of the first stage are
After cooling 20a, the superheated steam is recovered by the steam pipe, and the superheated steam is further introduced into the stationary blade 20b via the steam piping to the second stage stationary blade 20b to cool the blade, and then the stationary blade is cooled. Needless to say, the first cooling system 12 may be configured to recover the steam with the steam pipe provided on the blade 20b. When the second-stage stationary blade is also cooled, the consumption amount of superheated steam is reduced.

Another embodiment of the present invention will be described with reference to FIG. In FIG. 2, if the same symbols as in FIG.
The operation and the like are the same as those in the first embodiment. In FIG. 2, a gas turbine 5 equipped with the present invention is combined with a steam turbine plant 6, and an exhaust heat recovery boiler 7 and a generator 4a that generate steam for driving the steam turbine by utilizing exhaust heat from the gas tabine 5 are shown. A combined cycle power plant equipped is shown.

The combustion gas exhausted from the gas turbine 5 is guided to an exhaust heat recovery boiler 7 by a pipe (not shown), where it exchanges heat with the feed water from the steam turbine plant 6 and is exhausted to the outside. The exhaust heat recovery boiler 7 is of a three-pressure type and includes a low-pressure drum 8a, an intermediate-pressure drum 8b, and a high-pressure drum 8.
c is installed, and the low-pressure steam line 9a, the medium-pressure steam line 9b, and the high-pressure steam line 9c are connected to each other. The definitions of low pressure, medium pressure, and high pressure in the three-pressure formula are determined by the steam pressures that operate the low-pressure steam turbine 6a, the medium-pressure steam turbine 6b, and the high-pressure steam turbine 6c, respectively.
The vapor pressure increases in the order of low pressure, medium pressure, and high pressure. The low-pressure steam line 9a passes through the low-pressure superheater 7d and then the low-pressure steam turbine 6a.
Connected to. The superheated steam supplied to the low-pressure steam turbine 6a expands and drives the turbine, then becomes condensed water in the condenser 40, and is supplied to the exhaust heat recovery boiler 7 via the water supply line 9f. The medium pressure steam line 9b is connected to the medium pressure superheater 7c,
It is connected to the medium pressure steam turbine 6b via the reheater 7b.
Then, the steam discharged from the intermediate pressure steam turbine 6b is
Low-pressure steam line 9 connected through recovery steam line 9e
Join a. The high pressure steam line 9c is connected to the high pressure superheater 7a.
Then, superheated steam is supplied to the high-pressure steam turbine 6c. On the other hand, the high pressure steam line 9c is branched at a position upstream of the high pressure superheater 7a and is connected to the steam pipe 10 of the gas turbine 5. This superheated steam is introduced into the high pressure superheater 7a from the steam passage 14 of the second cooling system 15 as the cooling steam to the stationary blades and moving blades of the turbine, through the first cooling system 12 and the heat exchanger 16. It is collected by joining with the other branched high-pressure steam line 9c. The steam discharged from the high-pressure steam turbine 6c passes through the reheat steam line 9d and joins the connected intermediate pressure steam line 9b at a position upstream of the reheater 7b.

In the present embodiment thus constructed,
The air pressurized by the compressor 3 of the gas turbine 5 becomes high temperature and high pressure combustion gas in the combustor 2 and drives the turbine 1 to perform work. On the other hand, the combustion gas exhausted from the turbine 1 is sent to the exhaust heat recovery boiler 7 and the steam turbine plant 6
It is exchanged with water from the water supply and discharged. Exhaust heat recovery boiler 7
Then, the heat-exchanged feed water becomes low-pressure, medium-pressure and high-pressure superheated steam, and is collected in the low-pressure drum 8a, the medium-pressure drum 8b, and the high-pressure drum 8c. Steam conditions such as temperature and pressure of each drum are determined from optimum cycle conditions for driving the steam turbine plant 6. Here, focusing on the high pressure system that supplies the turbine stationary blades and the moving blades, the temperature of the combustion gas exhausted from the turbine 1 is generally about 600 ° C., and the steam condition supplied to the high pressure steam turbine 6c is the temperature. Is about 5
At 38 ° C, the pressure is set to about 103ata from the hs diagram (not shown) as a function of temperature and pressure. Therefore, in the high-pressure drum 8c, a steam condition of a temperature of about 330 ° C. and a pressure of about 140 ata is obtained from the pressure loss generated in the high-pressure steam line 9c and the supplied heat amount obtained by the high-pressure superheater 7a. The superheated steam generated in the high pressure drum 8c is
It is supplied to the first cooling system 12 at a rate of 3 to 5% with respect to the turbine inlet flow rate. The superheated steam supplied to the turbine stationary blades and the moving blades depends on the pressure loss in the first cooling system 12 and the second cooling system 15 and the cooling efficiency in the moving blades 30a and 30b. It is recovered in the second cooling system 15 when the pressure drops and the temperature rises by about 100 ° C. The recovered superheated steam is merged with the high pressure steam line 9c under relatively close pressure conditions to minimize the mixing loss at the time of merging, and the high pressure steam turbine 6c and the intermediate pressure steam turbine 6 are also combined.
b, and can contribute to the work of the low-pressure steam turbine 6a.

By incorporating the above-described system for supplying and recovering superheated steam to the turbine stationary blades and moving blades into a three-pressure type combined cycle power plant, it is possible to easily achieve and realize steam cooling of turbine blades. In addition, the maximum combined cycle efficiency when using high-pressure steam can be exhibited.

A third embodiment of the present invention will be described with reference to FIG. In FIG. 3, if the same symbols as in FIGS. 1 and 2 are used, the configuration, operation, etc. are the same as those in the first and second embodiments.
However, high pressure, medium pressure, and low pressure steam lines 9a, 9b, 9
Exclude c. In this embodiment, the medium pressure drum 8
The steam from b is used for cooling the turbine stationary blades and moving blades.

The low pressure steam line 9a is connected to the low pressure steam turbine 6a via a low pressure superheater 7d. The superheated steam supplied to the low-pressure steam turbine 6a expands and drives the turbine, then becomes condensed water in the condenser 40, and the water supply line 9f
And is supplied to the exhaust heat recovery boiler 7. The intermediate pressure steam line 9b is connected to the steam pipe 10 of the gas turbine 5 after passing through the intermediate pressure superheater 7c. This superheated steam is used as cooling steam for the stationary blades and moving blades of the turbine through the first cooling system 12 and the heat exchanger 16, and then from the recovery pipe 14 of the second cooling system 15.
It is supplied to the intermediate pressure steam turbine 6b via the reheater 7b.
Here, a part of the intermediate pressure steam line 9b is connected to the first cooling system 1
2 steam piping 10 and second cooling system 15 recovery piping 1
It becomes the composition which also serves as 4. And the medium pressure steam turbine 6b
The steam discharged from the fuel cell joins the low pressure steam line 9a connected through the recovery steam line 9e. The high pressure steam line 9c supplies superheated steam to the high pressure steam turbine 6c via the high pressure superheater 7a. The steam discharged from the high-pressure steam turbine 6c joins the medium-pressure steam line 9b connected through the reheat steam line 9d.

In the present embodiment thus constructed,
Focus on the medium pressure system that supplies superheated steam to turbine vanes and rotor blades. Steam conditions such as temperature and pressure of the medium pressure drum 8b are
It is determined from the optimum cycle conditions for driving the steam turbine plant 6. The superheated steam supplied to the high-pressure steam turbine 6c has a temperature of about 350 ° C. and a pressure of about 25 ata by performing work. The steam exhausted from the high-pressure steam turbine 6c then joins the intermediate-pressure steam line 9b connected through the reheat steam line 9d to drive the intermediate-pressure steam turbine 9b. Therefore, the medium pressure drum 8
The steam pressure of b must be the same as the exhaust steam from the high pressure steam turbine 6c. However, since the superheated steam from the intermediate pressure drum 8b once cools the turbine stationary blades and the moving blades, the pressure loss in the first cooling system 12 and the second cooling system 15 is about 35 ata and the temperature is about 35 ata. It is set to 240 ° C.
The superheated steam generated in the intermediate pressure drum 8b is superheated to about 270 ° C. in the intermediate pressure superheater 7c, and then supplied to the first cooling system 12 at a rate of 3 to 5% with respect to the turbine inlet flow rate. The superheated steam supplied to the turbine stationary blades and the moving blades causes pressure loss in the first cooling system 12 and the second cooling system 15, while the moving blades 3
Depending on the cooling efficiency at 0a and 30b, it will be recovered by the second cooling system 15 with a pressure drop of about 10 ata and a temperature rise of about 180 ° C. The recovered superheated steam is combined with the steam in the reheated steam line 9d under the same pressure condition,
In addition to minimizing the mixing loss at the time of merging, it is possible to contribute to the work of the intermediate pressure steam turbine 6b and the low pressure steam turbine 6a.

By incorporating the above-described system for supplying and recovering superheated steam to the turbine stationary blades and moving blades into a three-pressure type combined cycle power generation plant, steam cooling of the turbine blades can be easily achieved and realized. In addition, the maximum combined cycle efficiency when using medium pressure steam can be exhibited.

[0024]

According to the present invention, the stationary blades and the moving blades of the turbine can be cooled with the minimum steam flow rate, so that the excellent practical effect of maximizing the plant efficiency is brought about.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a steam cooling path of a turbine blade according to the present invention.

FIG. 2 is a diagram showing a configuration of a steam cooling path applied to a combined cycle power plant according to the present invention.

FIG. 3 is a diagram showing another embodiment showing a steam cooling path applied to a combined cycle power plant according to the present invention.

[Explanation of symbols]

1 ... Turbine, 5 ... Gas turbine, 6 ... Steam turbine plant, 7 ... Exhaust heat recovery boiler, 12 ... First cooling system, 15
... second cooling system, 16 ... heat exchanger, 20a, 20b ... stator blade,
30a, 30b ... moving blades.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F01K 23/10 F01K 23/10 C F02C 3/30 F02C 3/30 Z (72) Inventor Manabu Matsumoto 502 Jinritsucho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Seisakusho Co., Ltd. (72) Naruhisa Sugita 502, Kintatecho, Tsuchiura-shi, Ibaraki Hiratsugi Seisakusho Co., Ltd. (72) Inventor Shinya Enshima Shinya Ibaraki 502 Kintatecho, Tsuchiura-shi, inside the Mechanical Research Laboratory, Hiritsu Seisakusho Co., Ltd. (72) Inventor, Shinichi Higuchi, 502, Shintachi-cho, Tsuchiura City, inside the Mechanical Research Laboratory, Hitachi, Ltd. (72) Inventor Isamu Takehara, Saiwaicho, Hitachi-shi, Ibaraki Prefecture 3-1, 1-1 Hitachi Ltd. Hitachi factory

Claims (2)

[Claims] 1. In a gas turbine equipment having a gas turbine having a stationary blade and a moving blade and a cooling system for cooling the stationary blade and the moving blade, the stationary blade is cooled with steam and the steam is recovered. A gas turbine facility comprising a first cooling system and a second cooling system for cooling the moving blade using the recovered steam and recovering the steam. 2. The gas turbine facility according to claim 1, further comprising a cooling means for cooling the steam from the first cooling system between the first cooling system and the second cooling system. Gas turbine equipment to do.