JP2000179354A - Refrigerant recovering gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerant recovering gas turbine which enables reduction of refrigerant pipes leading to a turbine blade section that is high- temperature and subject to cooling, prevents leakage of refrigerant, increases the work efficiency while decreasing human errors by largely reducing work on pipe assembly, and prevents damage to the pipes because of thermal unevenness in the pipes. SOLUTION: This refrigerant recovering gas turbine comprises moving blades 21 and stator blades 20. Each stator blade 20 has end walls inside and outside in its radial direction and has a refrigerant flow passage within the outside end wall and the stator blade 20. The gas turbine is formed to pass a refrigerant through the refrigerant passage via a refrigerant supply pipe to cool the stator blade 20 and recovers the refrigerant that has cooled the stator blade via a refrigerant recovery pipe. A refrigerant supply path 17a passing through a plurality of stator blades adjacent in the perimeter direction is installed to the outside end walls of the each stator blade 20. The refrigerant supply pipes 13 less than the stator blades 20 in number are disposed between the refrigerant supply path and a refrigerant supply source.

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 recovering refrigerant, and more particularly, to a gas turbine having an end wall of a stationary vane and a refrigerant passage inside the stationary vane. The present invention relates to a refrigerant recovery type gas turbine configured to cool and recover a refrigerant after stationary blade cooling.

[0002]

2. Description of the Related Art In recent gas turbines, the temperature of a working gas is increased in order to improve thermal efficiency, and a turbine blade disposed in the working gas can withstand this high temperature. In addition, a passage through which a cooling medium (refrigerant) flows is provided inside the blade, and the blade is directly cooled from the inside by flowing the refrigerant through the passage.

Conventionally, in a gas turbine of this type generally used, air extracted from a compressor is used as a cooling medium, and the cooling air is cooled by flowing through the inside of a turbine blade. The cooling air after cooling the inside of the blade is discharged into the working gas for film cooling on the outer surface of the blade, from the trailing edge of the blade, and the like as seal air for the wheel space. This is a so-called open cooling system.

In this open cooling system, since the cooling air is discharged into the working gas, the temperature of the working gas decreases due to dilution of the cooling air, which is relatively low in temperature, and when the cooling air is mixed into the working gas. Since the output of the turbine is reduced due to a mixing loss or the like generated between the working gas and the like, there is a tendency that the effect of increasing the temperature cannot be sufficiently exhibited.

[0005] Further, as the temperature of the gas turbine is increased, the third generation gas turbine which is currently being developed is
The turbine inlet temperature becomes 1500 ° C class. In this class, it is known that the consumption of the cooling air mainly for the turbine blades and the sealing air to the wheel space and the like increases, and conversely, the merits in the cycle due to the high temperature are impaired.

Recently, as a remedy, a cooling air recovery type gas turbine that recovers cooling air after cooling the stationary vanes to a combustor without discharging the cooling air into the working gas, and a recovery turbine of the same type. A gas turbine using steam having a high heat transfer coefficient as a cooling medium (reduction of refrigerant consumption and contribution of work by recovery to a steam system) has been proposed. Examples of this type of refrigerant recovery type gas turbine include Japanese Patent Publication No. 58-43575 and Japanese Patent Application Laid-Open No. Sho 62-43575.
-294703 and the like.

[0007]

In order to efficiently realize the refrigerant recovery type gas turbine according to the purpose, it is important to control the supply and recovery of the cooling medium. That is, supply
An object of the present invention is to reduce the amount of cooling medium, including leakage, in the recovery path and in the turbine section, which is the part to be cooled, and to make the cooling medium effectively contribute to work.

FIG. 2 shows a configuration of a conventional cooling medium supply and recovery pipe for a part of an upper half casing. Based on two refrigerant chambers provided inside the turbine casing, piping is branched to supply and recover refrigerant. In a turbine that is branched into a supply pipe and a recovery pipe whose number is equal to the number of blades, there is a possibility that a leak may occur at a connection portion of the pipe.

Further, these pipes, apart from a large-capacity gas turbine, require assembling work in a small internal space of the casing, which makes difficulties difficult and reduces connection reliability.

[0010] Further, a structure is required to absorb the relative thermal expansion in the radial direction between the turbine casing, the piping, and the cooling blades, but the seal is formed by dividing the piping perpendicularly to the flow direction of the refrigerant. Leakage may occur in the structure.
In this case, a method of evacuating thermal expansion by helical piping is also conceivable.However, helical piping requires a large space inside the turbine, so the cooling air increases due to the expansion of the mainstream heat transfer area, including the design change of the gas path itself. And other problems occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to reduce the number of cooling medium pipes to turbine blades, which are high-temperature parts to be cooled, to prevent leakage of cooling medium, and Provided is a refrigerant recovery type gas turbine of this type that can improve work efficiency and reduce human error by significantly reducing piping assembly work, and can also prevent damage to piping due to thermal unevenness of piping groups. It is in.

[0012]

That is, the present invention provides a moving blade driven by high-pressure gas from a combustor, and a stationary blade disposed on a fixed portion upstream of the moving blade and guiding the high-pressure gas. A plurality of the stationary blades are arranged in the circumferential direction, and have an inner end wall and an outer end wall inside and outside in a radial direction of each stationary blade, and are provided inside the outer end wall and the stationary blade. In a refrigerant recovery type gas turbine having a refrigerant flow passage, the refrigerant is supplied from a refrigerant supply source through a refrigerant supply pipe to the refrigerant flow passage to cool and collect the stationary vanes. The outer end wall of the blade is provided with a refrigerant supply passage communicating with a plurality of circumferentially adjacent stationary blades, and the number of the stationary blades is provided between the refrigerant supply passage and the refrigerant supply source. Provide fewer refrigerant supply pipes Way is obtained so as to achieve the intended purpose.

[0013] In this case, the refrigerant supply pipe is provided on an outer end wall portion of the vane located substantially at the center of the refrigerant supply communication passage extending over a plurality of circumferentially adjacent vanes. It is like that.

Further, the present invention includes a moving blade driven by high-pressure gas from a combustor, and a stationary blade disposed on a fixed portion upstream of the moving blade and guiding the high-pressure gas. A plurality of blades are arranged in the circumferential direction, have an inner end wall and an outer end wall inside and outside in the radial direction of each stator blade, and have a refrigerant flow passage inside the outer end wall and the stator blade. A refrigerant recovery formed to flow the refrigerant from the refrigerant supply source through the refrigerant supply pipe through the refrigerant flow passage to cool the stationary vanes, and to collect the refrigerant after the stationary vane cooling through the refrigerant recovery pipe. In the type gas turbine, a refrigerant supply communication passage and a refrigerant recovery communication passage are provided on the outer end wall of each of the stationary blades so as to extend over a plurality of circumferentially adjacent stationary blades. Between the coolant supply The electrostatic refrigerant supply pipe smaller than the number provided in the wing, and between the coolant-collecting path and the refrigerant recovery unit is obtained by so providing the refrigerant recovery pipe smaller than the number of vanes.

[0015] In this case, the refrigerant supply pipe and the refrigerant recovery pipe may be connected to a plurality of stationary blades adjacent to each other in the circumferential direction, and the outer end of the stationary blade located at a substantially central portion of the refrigerant supply communication passage. This is provided on the wall. Further, the number of refrigerant supply communication passages that are communicated across the plurality of stationary blades is made equal to the number of circumferential divisions of the turbine casing.

Further, a flow rate adjusting means for adjusting an amount of the refrigerant flowing from the refrigerant supply path into the refrigerant flow path of the stationary blade, for example, a throttle mechanism is provided in the refrigerant supply path portion. Further, the connecting portion between the outer end walls adjacent to each other in the circumferential direction is formed into an uneven fitting connection, and the coolant supply communication passage is provided at the core of the uneven fitting portion. Further, a seal device for preventing leakage of the refrigerant is provided in the concave-convex fitting portion.

That is, in the refrigerant recovery type gas turbine formed as described above, the outer end wall of each vane is provided with a refrigerant supply passage communicating with a plurality of circumferentially adjacent vanes. Since the number of the refrigerant supply pipes is smaller than the number of the stationary blades between the refrigerant supply passage and the refrigerant supply source, the cooling medium for cooling the blades has a small number of supply paths. Can be introduced into the vane segment and communicate with the adjacent vane segment, thus greatly reducing piping and assembling work, i.e., improving work efficiency and manpower by greatly reducing piping assembling work. This makes it possible to reduce mistakes in the design and prevent damage to the piping due to thermal unevenness of the piping group.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a cross-sectional view of a main part of the refrigerant recovery type gas turbine. 25 is a turbine casing, 10 is a supply path, 13 is a refrigerant supply pipe for supplying a refrigerant, 14 is a refrigerant recovery pipe thereof, and 20 is a stationary blade.

Next, before describing these structural relationships,
Referring to FIG. 3, the overall configuration will be described from the flow of the working gas and the steam. The combined power generator mainly includes a turbine 3, a compressor 1 connected to the turbine 3 to obtain compressed air for combustion, a high-temperature high-pressure gas A steam turbine 5 comprising a combustor 2 for generating steam and a heat recovery steam generator 9 for generating steam for driving a steam turbine using exhaust heat from the gas turbine 4 and a generator 6. I have.

The combustion gas exhausted from the gas turbine 4 is led to an exhaust heat recovery boiler 9 where the steam turbine 5
It exchanges heat with the water supply from the tank and is exhausted to the outside. The exhaust heat recovery boiler 9 includes a drum 30, an evaporator 37, and a primary superheater 35.
a and a tertiary superheater 35b, and a steam supply line 3 for supplying steam to the steam turbine 5.
1 is connected. The steam supplied to the steam turbine 5 expands and drives the steam turbine 5,
And a part is circulated and supplied directly to a secondary economizer 36 of the exhaust heat recovery boiler 9 through a water supply line 33 by a water supply pump 34 for partly heating the pre-cooler 7 with cooling air.

Next, the flow of the cooling air supplied to the turbine unit will be described. The cooling air extracted from the compressor 1 is supplied to the cooling air supply path 10 to the turbine 3.
A first supply pipe 12a, a second supply pipe 12b,
After passing through the pre-cooler 7 and the boost compressor 8 along the third supply pipe 12c, it is guided to the inside of the turbine 3. After passing through the cooling passage of the stationary blade, the cooling air introduced into the turbine 3 is recovered by the combustor 2 through the recovery path 11.

Here, the flow of the cooling air in the turbine 3 will be described in detail in the order of FIG. 4, FIG. 5, and FIG. The turbine 3 of the present embodiment includes a four-stage stationary blade 20 and a moving blade 21, and has a structure for collecting the cooling air of the second-stage stationary blade as described above.

The cooling air guided from outside the turbine casing 25 to the turbine 3 is supplied to the support 28a of the shroud 27a of the first stage moving blade 21a, the support 28b of the shroud 27b of the second stage moving blade 21b, and the second stage. Stationary wing 2
It is led to the stationary blade segment 22b via the supply pipe 13 arranged in the space 29 formed by the zero. In the vicinity of the turbine casing 25 and the stationary blade segment 22b, the joint 4
The stationary blade segment 22 b directly connected to the supply pipe 13 connected by 5 becomes the first stationary blade segment 40.

With the stationary vane segment 22b arranged at the center,
The adjacent stationary blade segments 22a and 22c constitute a second stationary blade segment group 41. The first stationary blade segment 40 and the second stationary blade segment group 41 form adjacent outer diameter side end walls 24a, 24b, 24c in a concave shape, and form outer diameter side end walls 23a, 23b in a convex shape, Connected.

The cooling air supplied to the first stationary blade segment 40 is branched and flows into the second stationary blade segment group 41 through the supply-side communication hole 17a. In addition, a metal O-ring 26 for high temperature is provided at a connection portion of the uneven outer diameter side end wall. Further, the inside of the outer diameter side end walls 24a and 23c of the second stationary blade segment group 41 is as follows.
It is sealed in the circumferential direction by the closing plates 18a and 18c. Furthermore, since the stationary blade segments are manufactured in the same mold, the supply pipe 13 is also connected to the second stationary blade segment group 41. Therefore, the closing plate 46a
And 46c.

The supply side communication hole 17a and the stationary blades 20a, 20
Supply-side cooling holes 15a, 15b, 15c for connecting cooling passages (not shown) provided inside b, 20c are provided with orifices 16a, 16b, 16c. The orifices 16a and 16c are the same,
The flow coefficient of 6b is designed to be smaller than other orifices.

The stationary blade 20 of the second stationary blade segment group 41
The cooling air that has passed through the cooling passages a and 20c is connected to the collecting-side communication holes 17b through the collecting-side cooling holes 19a and 19c.
It goes to the stationary blade segment 22b having the recovery pipe 14 connected to the space 29 in the same manner as the supply pipe 13 using the joint 45. These stationary blade segments 22a and 22c to which the recovery pipe is not connected form a fourth stationary blade segment group 43.

On the other hand, the stationary blade segment 22 is
The cooling air flows from the cooling passage of the stationary blade 20b through the recovery side cooling hole 19b, and the fourth stationary blade segment group 44 through the recovery side communication hole 17b.
After being merged with the flow in the above, it is guided to the outside of the turbine casing 25 via the recovery pipe 14, and then recovered by the combustor 2.

In this embodiment, the first stationary blade segment 40
And the third stationary blade segment 42, the second stationary blade segment group 41, and the fourth stationary blade segment group 43 have the same configuration as a segment. A plurality of segment blocks 44 composed of the first stationary blade segment 40 and the second stationary blade segment group 41 or the third stationary blade segment 42 and the fourth stationary blade segment group 43 are arranged in the circumferential direction. ing.

In the present embodiment configured as described above,
The high-temperature and high-pressure working gas generated in the compressor 1 and the combustor 2 along with the operation of the gas turbine 4 flows into a first stage stationary blade provided in the turbine at a pressure of about 25 ata and a temperature of about 1400 ° C. The pressure and the temperature are reduced while the turbine works, and after flowing out of the final stage rotor blade at about 600 ° C., it is guided to the exhaust heat recovery boiler 9 along a duct (not shown). The steam generated by the exhaust heat recovery boiler 9 is supplied to the steam turbine 5
And the generator 6 directly connected to the steam turbine 5 rotates to obtain electric power.

At this time, a part of the high-pressure air obtained by the compressor 1 is extracted and used as cooling air. However, since the temperature of the extracted air in the compressor 1 is as high as about 500 ° C., the first supply pipe At 12a, the bleed air is led to the pre-cooler 7 to reduce the temperature to about 150 ° C. Further, the supply pressure for returning the extracted air to the combustor 2 as the cooling air needs to be set so that the recovery pressure is larger than 25 ata in consideration of the pressure loss in the portion to be cooled.

For this reason, the bleed air whose temperature has been reduced by the pre-cooler 7 is led to the boost compressor 8 through the second supply pipe 12b.
Only when the pressure is increased to about 0 ata, can cooling air on the high-stage side be used. The cooling air exchanges heat inside the stationary blades and the like to lower the metal temperature within the allowable temperature of the blade material. Thereafter, the cooling air is recovered to the combustor 2 along the recovery pipe 11a corresponding to the recovery path 11 and increases the turbine output.

The cooling air guided from the outside of the turbine casing 25 is one time smaller than the number of blades of the second stage stationary blade 20.
The number of supply pipes 13 is divided into the number of the supply pipes 13, and flows into the segment blocks 44. In each segment block, the flow is distributed to the stationary blades 20a, 20b, 20c almost uniformly by the orifices 16a, 16b, 16c having different flow coefficients in order to correct the deviation of the flow distribution with respect to the branch flow.

The uneven connecting portion between the first stationary blade segment 40 and the second stationary blade segment group 41 communicates with the supply side communication hole 17a and the gas path and the space 29.
Sealed by metal O-ring 26. The recovery path is established in the reverse pattern of the supply, and after reducing the cooling passage of the stationary blade, the number of the recovery pipes 14 is reduced to 1/3 in the same manner as the supply pipe.
Through the combustor.

The outer diameter side end wall described above is
In the refrigerant recovery type gas turbine communicating in the circumferential direction, by reducing the number of supply pipes and recovery pipes, the occurrence of leakage at the joint portion is prevented beforehand, so that the effect as a refrigerant recovery type gas turbine can be sufficiently exhibited. .

In addition, sealing air is required so that the mainstream gas does not leak from the gas path to the space side. Conventionally, a method of mounting a seal plate in a seal groove is adopted between segments. In this method, two leak channels sandwiching the seal plate are formed on adjacent segment surfaces. However, by forming the end wall into an uneven shape and connecting it, the leakage flow path is cut off on the convex stationary blade segment side, the seal air flow rate can be halved, and the gas turbine with high thermal efficiency Can be obtained.

Also, compared to a configuration in which piping for the number of blades is provided, particularly in a small-capacity gas turbine, the space is small, so that the piping work is difficult, but in this embodiment, the number of piping is reduced to 1/3. As a result, the working space is increased and the number of working steps is reduced, and a highly reliable gas turbine can be expected by reducing human error.

From the gist of the present invention, if the number of members of the second stationary blade segment group is increased, the effect is of course dramatically improved. And further reduction of cooling air piping can fundamentally eliminate the problem of relative thermal expansion between turbine casing and piping and stator blade segments,
A highly reliable recovery type gas turbine can be obtained.

Further, two segment blocks are used to divide the turbine casing into an upper half casing and a lower half casing, and a supply pipe for the first stator blade segment and a recovery pipe for the third stator blade segment are arranged vertically in each casing. If they are arranged on a line, the joint on the casing side connected in the space can be arranged outside the turbine casing, so that the working environment is further improved.

Although the present embodiment has been described with respect to only the second stage stationary blade, a greater effect can be expected if the present invention is applied to each stage stationary blade.

[0041]

As described above, according to the present invention, it is possible to reduce the number of cooling medium pipes to the turbine blade, which is a high-temperature cooled part, and it is possible to sufficiently prevent the leakage of the cooling medium. In addition, it is possible to obtain a refrigerant recovery type gas turbine capable of improving work efficiency and reducing human errors by greatly reducing piping assembly work, and preventing piping damage due to thermal unevenness of the piping group.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view and a longitudinal sectional front view of an essential part showing an embodiment of a refrigerant recovery type gas turbine of the present invention.

FIG. 2 is a sectional view showing a piping configuration of a cooling medium of a conventional refrigerant recovery type gas turbine.

FIG. 3 is a system diagram showing a gas turbine plant provided with a refrigerant recovery type gas turbine of the present invention.

FIG. 4 is a vertical sectional side view showing a main part of an embodiment of the refrigerant recovery type gas turbine of the present invention.

FIG. 5 is a partially cutaway view of the outer end wall of the refrigerant recovery type gas turbine of the present invention as viewed from the outside in the radial direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Combustor, 3 ... Turbine, 4 ... Gas turbine, 10 ... Supply path, 11 ... Recovery path, 13 ... Supply pipe, 14 ... Recovery pipe, 17a ... Supply side communication hole, 17b ...
Collection side communication hole, 20: stationary blade, 21: moving blade, 25: turbine casing, 40: first stationary blade segment, 41: second stationary blade segment, 42: third stationary blade segment, 4
3 ... fourth stator blade segment, 44 ... segment block.

Claims (9)

[Claims] 1. A moving blade driven by a high-pressure gas from a combustor, and a stationary blade disposed on a fixed portion side upstream of the moving blade and guiding the high-pressure gas, wherein the stationary blade includes: A plurality of the refrigerants are provided in the circumferential direction, have an inner end wall and an outer end wall inside and outside the radial direction of each vane, and have a refrigerant flow passage inside the outer end wall and the vane. In a refrigerant recovery type gas turbine formed so as to cool and collect a stationary blade by flowing a refrigerant from a refrigerant supply source through a refrigerant supply pipe to a flow passage, an outer end wall of each of the stationary blades has a circumferential direction. Provide a refrigerant supply communication passage that communicates across a plurality of stationary blades adjacent to the,
A refrigerant recovery type gas turbine wherein a number of refrigerant supply pipes less than the number of the stationary blades are provided between the refrigerant supply passage and the refrigerant supply source. 2. The refrigerant supply pipe is provided on an outer end wall portion of a stationary blade located substantially at a center of a refrigerant supply communication passage that is communicated across a plurality of circumferentially adjacent stationary blades. A refrigerant recovery type gas turbine according to claim 1. 3. A moving blade driven by high-pressure gas from a combustor, and a stationary blade disposed on a fixed portion side upstream of the moving blade and guiding the high-pressure gas, wherein the stationary blade comprises: A plurality of the refrigerants are provided in the circumferential direction, have an inner end wall and an outer end wall inside and outside the radial direction of each vane, and have a refrigerant flow passage inside the outer end wall and the vane. A refrigerant recovery type gas turbine formed to circulate a refrigerant from a refrigerant supply source through a refrigerant supply pipe to a flow passage to cool the vanes, and to collect the refrigerant after the vane cooling through a refrigerant recovery pipe. In the outer end wall of each of the stationary blades, a refrigerant supply communication passage and a refrigerant recovery communication passage communicating with a plurality of circumferentially adjacent stationary blades are provided, and the refrigerant supply communication passage and the refrigerant supply source are provided. Between the number of said vanes Ri refrigerant supply pipe provided small, and the between the coolant-collecting path and the refrigerant recovery unit, the refrigerant recovery type gas turbine, characterized in that it has to provide a refrigerant recovery pipe smaller than the number of vanes. 4. An outer end wall portion of a vane located substantially at the center of a refrigerant supply communication passage in which the refrigerant supply pipe and the refrigerant recovery pipe communicate with each other over a plurality of circumferentially adjacent stationary vanes. 4. The refrigerant recovery type gas turbine according to claim 3, wherein the gas turbine is provided in a gas turbine. 5. The method according to claim 1, wherein the number of the refrigerant supply communication passages extending across the plurality of stationary blades is formed equal to an integral multiple of the number of circumferential divisions of the turbine casing. The gas turbine of claim 1. 6. The refrigerant supply communication passage portion is provided with a flow rate adjusting means for adjusting an amount of refrigerant flowing from the refrigerant supply passage into the refrigerant flow passage of the stationary blade. The gas turbine of claim 1. 7. The refrigerant recovery type gas turbine according to claim 6, wherein a throttle mechanism is used as said flow rate adjusting means. 8. A connecting portion between the outer end walls which are adjacent in the circumferential direction is formed into an uneven fitting connection, and the coolant supply communication passage is provided at a core of the uneven fitting portion. A refrigerant recovery type gas turbine according to any one of claims 1 to 7. 9. The refrigerant recovery type gas turbine according to claim 8, wherein a seal device for preventing leakage of the refrigerant is provided in the concave-convex fitting portion.