JP2006046088A - Steam turbine plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam turbine plant having a high-medium-pressure integral type structure which accommodates high-pressure and medium-pressure turbines in a turbine casing, wherein the realization of the high temperature of reheating steam supplied to the medium-pressure turbine is achieved. <P>SOLUTION: In the steam turbine plant which has a high-medium-pressure integral type structure for accommodating a high-pressure turbine part 2 and a medium-pressure turbine part 3 in a turbine casing 1, when steam reversed from an outlet in a high-pressure turbine first stage 9a of a high-pressure turbine part 2 is supplied to wheels 18a, 18b in a medium-pressure turbine first stage 14a in the medium-pressure turbine part 3 through the medium of an intermediate gland part 16 provided so as to straddle the high-pressure turbine nozzle box 5 and the high-pressure and medium-pressure turbine parts 2, 3, a cooling steam supply means 23 for supplying cooling steam to the steam reversed from the outlet in the high-pressure turbine first stage 9a of the high pressure turbine part 2 to be mixed is provided to the intermediate gland part 16. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steam turbine plant, and more particularly, to a high-medium pressure integrated structure in which a high-pressure turbine and an intermediate-pressure turbine are accommodated in a single turbine casing. The present invention relates to a steam turbine plant having a structure for increasing the temperature of the steam generator.

In recent steam turbine plants, while further improving the plant thermal efficiency, fuel consumption is reduced under further improvements in plant thermal efficiency, resulting in CO ₂ gas, SOx gas, NOx gas, etc. as environmental pollution sources. It is planned as one measure that can reduce the amount of pollutant gas generated. For this reason, efforts have been made to further increase the temperature of steam.

  Conventionally, a steam turbine plant has a steam temperature of about 600 ° C., and for such high-temperature steam, a ferritic heat-resistant steel is used for turbine nozzles, turbine blades, turbine rotors and the like, which are main components of the steam turbine. Used to maintain high strength.

  However, when the steam temperature is increased to 650 ° C or higher under high temperatures, ferritic materials such as CrMoV steel and 12Cr steel show steam oxidation, which is no longer a guarantee of maintaining high strength. Limitations have been made, and changes to austenitic materials such as Ni-based alloys and Co-based alloys are being studied.

  For example, in Japanese Patent Application Laid-Open No. 7-247806 (Patent Document 1), a high-medium pressure integrated structure in which a part of a high-pressure turbine and a part of an intermediate-pressure turbine are accommodated in one turbine casing, the steam temperature becomes 650 ° C. or higher. Austenitic materials are used for the components of the high-medium pressure integrated structure, conventional ferrite materials are used for the remaining steam turbine components, and austenitic and ferrite materials are used separately depending on the temperature. Proposals have been made.

  JP 2000-282808 A (Patent Document 2) divides the components of the steam turbine and uses austenitic materials for the components that handle steam at a temperature of 650 ° C. or higher among the divided components. When the steam temperature is around 600 ° C., a proposal has been made to use a ferrite-based material.

In Japanese Patent Laid-Open No. 2001-82109 (Patent Document 3), a separate high pressure turbine is provided in a conventional (general) steam turbine, and an austenitic material is used for the separate high pressure turbine. Proposals have been made to use ferritic materials for steam turbines.
JP-A-7-247806 JP 2000-282808 A JP 2001-82109 A

  Patent Documents 1 to 3 both use an austenitic material for a steam turbine component having a steam temperature of 650 ° C. or higher, and a conventional ferrite system for a steam turbine component having a steam temperature of around 600 ° C. However, there are still some concerns about using austenitic materials for components of steam turbines with steam temperatures of 650 ° C or higher. ing.

  Austenitic materials can maintain and guarantee a sufficiently high strength against steam at a temperature of 650 ° C or higher, but have low thermal conductivity, large thermal expansion due to temperature differences, and excessive thermal stress in high-thickness parts. Occurs. For this reason, there is a concern about cracks and the like.

  In addition, austenite-based materials may cause segregation and defects such as nests during production. For this reason, the production amount is naturally limited and the cost is increased. On the other hand, when the defective portion is taken into consideration, there is a certain amount of anxiety about forging and casting.

  A technology that can be used to cope with the high steam temperature has been developed without using the austenitic material that has some problems like this. It is being sought on the way.

  During the search for higher steam temperatures, a detailed observation and discussion of the steam turbine plant revealed that in the first stage of the turbine, a portion of the steam supplied from the turbine nozzle box and finished the expansion work was inverted, and the turbine nozzle It has been confirmed that it flows from the outer peripheral side of the box to the intermediate pressure turbine wheel (turbine disk) through the intermediate ground portion to cool the turbine blade wheel (implanted portion).

  If this cooling technology is incorporated into a steam turbine plant, it is considered that the steam temperature can be sufficiently increased.

  In particular, since the intermediate pressure turbine has a relatively low steam pressure, the thickness of the ferrite-based material is thin, and it is difficult to generate excessive thermal stress. It is considered more feasible to supply the medium pressure turbine than to supply steam.

  The present invention has been made based on such observations and considerations. The high-pressure turbine and the intermediate-pressure turbine are accommodated in one turbine casing to form a high-medium-pressure integrated structure. An object of the present invention is to provide a steam turbine plant that incorporates a cooling technology into a pressure turbine to maintain and guarantee high strength and to increase the temperature of the supplied steam.

  In order to achieve the above object, a steam turbine plant according to the present invention has a high and medium pressure integrated structure in which a high pressure turbine section and an intermediate pressure turbine section are accommodated in one turbine casing as described in claim 1. In the steam turbine plant, the steam reversed from the outlet of the first stage of the high-pressure turbine of the high-pressure turbine section is passed through the high-pressure turbine nozzle box and the intermediate ground portion provided across the high-pressure turbine section and the intermediate-pressure turbine section. When supplying to the wheel of the first stage of the intermediate pressure turbine in the intermediate pressure turbine section, the cooling ground supply means for supplying and mixing the cooling steam to the steam inverted from the outlet of the first stage of the high pressure turbine of the high pressure turbine section is the intermediate ground section Is provided.

  Further, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention is the cooling steam supply means as the cooling steam supply pipe as described in claim 2, and the cooling steam supply pipe is connected to the high-pressure turbine. This is configured to be connected to a bleed pipe provided in the high-pressure turbine stage of the section.

  Moreover, in order to achieve the above-described object, the steam turbine plant according to the present invention is provided with a bleed pipe in the final stage of the high-pressure turbine in the high-pressure turbine section.

  In order to achieve the above-mentioned object, the steam turbine plant according to the present invention is the cooling steam supply means, which is a cooling steam supply pipe as described in claim 4, and the cooling steam supply pipe is connected to the high-pressure turbine. It connects with the low-temperature reheat steam pipe provided in the high pressure turbine exhaust chamber of the part.

  Moreover, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention is a high and medium pressure integrated type housing a high pressure turbine section and an intermediate pressure turbine section in one turbine casing as described in claim 5. In the steam turbine plant having the structure, the steam reversed from the outlet of the first stage of the high pressure turbine of the high pressure turbine section is provided via a high pressure turbine nozzle box and an intermediate ground portion provided across the high pressure turbine section and the intermediate pressure turbine section. When the intermediate pressure turbine section is supplied to the first-stage wheel of the intermediate-pressure turbine, steam recovery means for extracting a part of the inverted steam from the outlet of the first-stage high-pressure turbine of the high-pressure turbine section is provided in the intermediate ground section. In addition, cooling steam supply means for supplying and mixing cooling steam to the remaining steam is provided in the intermediate ground portion. It is.

  In the steam turbine plant according to the present invention, in order to achieve the above-described object, the steam recovery means is a steam recovery pipe, and the steam recovery pipe is used as a high-pressure turbine section high-pressure turbine section. It is configured to be connected to a bleed pipe provided in the turbine stage.

  In order to achieve the above object, the steam turbine plant according to the present invention has a steam recovery pipe as a steam recovery pipe as described in claim 7, and this steam recovery pipe is used as a high pressure turbine section. It is configured to be connected to a low-temperature reheat steam pipe provided in the turbine exhaust chamber.

  Further, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention includes a cooling steam supply adjusting valve that is controlled to open and close in accordance with load fluctuations. It is provided.

  Moreover, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention includes, as described in claim 9, the steam recovery means includes a steam recovery adjustment valve that is controlled to open and close in accordance with load fluctuations. Is.

  Moreover, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention is a high-medium pressure integrated type housing a high-pressure turbine part and an intermediate-pressure turbine part in one turbine casing as described in claim 10. In the steam turbine plant having a structure, the intermediate pressure in the intermediate pressure turbine section is provided through an intermediate ground portion provided across the high pressure turbine section and the intermediate pressure turbine section from outside the high pressure turbine nozzle box provided in the high pressure turbine section. Cooling steam supply means for supplying cooling steam to the wheel of the turbine stage is provided in the high-pressure turbine nozzle box.

  Moreover, in order to achieve the above-mentioned object, the steam turbine plant according to the present invention is a high-medium-pressure integrated type housing a high-pressure turbine part and an intermediate-pressure turbine part in one turbine casing as described in claim 11. In a steam turbine plant having a structure, a high-pressure turbine nozzle box and a medium-pressure turbine stage wheel in the intermediate-pressure turbine section are provided in the high-pressure turbine section from an intermediate ground portion provided across the high-pressure turbine section and the intermediate-pressure turbine section. And a cooling steam supply means for supplying the cooling steam in a divided manner to each of the first and second intermediate ground portions.

  In order to achieve the above-mentioned object, the steam turbine plant according to the present invention is the cooling steam supply means as described in claim 12, wherein the cooling steam supply pipe is connected to the boiler. It is configured to be connected to the middle part of the superheater.

  In order to achieve the above-mentioned object, in the steam turbine plant according to the present invention, the cooling steam supply means is a cooling steam supply pipe, and the cooling steam supply pipe is connected to the boiler. It is configured to be connected to the inlet side of the superheater.

  The steam turbine plant according to the present invention includes a cooling steam supply means for supplying high-pressure turbine exhaust as cooling steam to an intermediate-pressure turbine section through an intermediate gland section, and an outer side of a high-pressure turbine nozzle box of the high-pressure turbine section. With steam recovery means that recovers the steam flowing from the middle to the intermediate grant section, and has a proven record of maintaining high strength even if reheat steam at a temperature of 650 ° C or higher is supplied to a medium-pressure turbine with a high-medium pressure integrated structure. High ferritic material can be applied as it is to turbine components to increase the temperature of the intermediate pressure turbine section, and steam flowing outside the high pressure turbine nozzle box can be effectively recovered.

  Hereinafter, an embodiment of a steam turbine plant according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.

  FIG. 1 is a partially cutaway, partially broken schematic longitudinal sectional view showing a first embodiment of a steam turbine plant according to the present invention. FIG. 1 shows only the upper half portion and omits the lower half portion.

  The steam turbine plant according to the present embodiment has a high-medium pressure integrated structure in which a high-pressure turbine section 2 and an intermediate-pressure turbine section 3 are accommodated in one turbine casing 1.

  In the high-medium pressure integrated structure, the high-pressure turbine section 2 is arranged in the axial direction of the high-pressure turbine nozzle box (steam chamber) 5 that communicates with the main steam pipe 4 and the turbine rotor 6. A turbine stage 9 including a moving blade 8 and a high-pressure turbine exhaust chamber 10 are provided, and main steam supplied from a boiler (not shown) via a main steam pipe 4 is guided to a high-pressure turbine nozzle box 5. The main steam supplied here is subjected to expansion work in the high-pressure turbine stage 9 to generate power, and the high-pressure turbine exhaust of the main steam that has finished the expansion work is guided to the high-pressure turbine exhaust chamber 10, from which the boiler is restarted. It is configured to supply to a heater (not shown).

  The turbine stage 9 includes a plurality of stages. The first (turbine nozzle box side) is referred to as the turbine nozzle 7a and the turbine blade 8a as a set, and the last (turbine exhaust chamber side) is referred to as the turbine nozzle 7a. 7b and the high-pressure turbine final stage 9b including the turbine rotor blade 8b.

  Similarly to the configuration of the high-pressure turbine unit 2, the intermediate-pressure turbine unit 3 is also disposed in the axial direction of the intermediate-pressure turbine nozzle box 11 communicated with the reheat steam pipe 10 and the turbine rotor 6. 12 and an intermediate pressure turbine stage 14 having a turbine rotor blade 13 as a set, and an intermediate pressure turbine exhaust chamber 15. The reheat steam supplied from the boiler reheater via the reheat steam pipe 17 The reheat supply that is guided to the pressure turbine nozzle box 11 is expanded by the intermediate pressure turbine stage 14 to generate power, and the medium pressure turbine exhaust of the reheat steam that has completed the expansion work is discharged into the medium. The pressure turbine exhaust chamber 15 is guided and supplied to a low pressure turbine (not shown) from here.

  As in the case of the high pressure turbine section 2, the intermediate pressure turbine stage 14 includes a plurality of stages, the first being referred to as an intermediate pressure turbine first stage 14 a in which the turbine nozzle 12 a and the turbine rotor blade 13 a are combined, and the last being the turbine. This is referred to as a turbine final stage 14b in which the nozzle 12b and the turbine rotor blade 13b are combined.

  On the other hand, an intermediate ground part 16 is provided across the high-pressure turbine part 2 and the intermediate-pressure turbine part 3. This intermediate gland part 16 is ejected from the high-pressure turbine nozzle box 5 of the high-pressure turbine part 2 and part of the steam that has finished the expansion work in the first stage 9a of the high-pressure turbine is inverted. The decompressed steam passes through the outside of the intermediate pressure turbine nozzle box 11 and the balance hole 19a of the wheels 18a, 18b provided in the intermediate pressure turbine first stage 14a and the intermediate pressure turbine second stage. , 19b for cooling.

  However, as a result of the trial calculation, the cooling steam supplied to the balance holes 19a and 19b of the wheels 18a and 18b is supplied from the reheat steam pipe 17 to the intermediate pressure turbine first stage 14a through the intermediate pressure turbine nozzle box 11. It was found that the temperature of the reheated steam is too high to be suitable for cooling.

  For this reason, the present embodiment is provided in the high-pressure turbine exhaust chamber 10 of the high-pressure turbine section 2 and is branched from a low-temperature reheat steam pipe 20 connected to a boiler reheater (not shown). A cooling steam supply pipe 23 that is connected to the jet port 22 of the intermediate gland portion 16 with a cooling steam supply adjusting valve 21 that is controlled to open and close in accordance with is provided.

  Further, in the present embodiment, in consideration of the high temperature of the steam flowing from the outside of the high-pressure turbine nozzle box 5 of the high-pressure turbine unit 2 to the intermediate gland unit 16, the present embodiment is provided at the suction port 24 of the intermediate gland unit 16. In the middle, a steam recovery pipe 27 is provided which is connected to the outlet side of the check valve 26 of the low temperature reheat steam pipe 20 via a steam recovery adjustment valve 25 which is controlled to open and close according to load fluctuations. is there.

  Here, the reason why the cooling steam supply adjusting valve 21 is provided in the cooling steam supply pipe 23 and the steam recovery adjusting valve 25 is provided in the steam recovery pipe 27 is as follows.

  In a steam turbine plant having a high-medium pressure integrated structure that supplies reheat steam having a temperature of 650 ° C. or higher to the intermediate pressure turbine unit 3, main steam supplied to each of the high pressure turbine unit 2 and the intermediate pressure turbine unit 3 during partial load operation. Steam and reheated steam are reduced in flow rate and pressure, but the temperature hardly decreases. For example, in the case of 50% load operation, both the main steam and the reheat steam are reduced only by about 10 ° C. For this reason, the temperature reduction range of the steam supplied from the outside of the high-pressure turbine nozzle box 5 of the high-pressure turbine unit 2 to the intermediate gland unit 16 is extremely small, and is not suitable for cooling the intermediate-pressure turbine unit 3.

  The present embodiment considers such an event, and when the temperature of the steam flowing from the outside of the high-pressure turbine nozzle box 5 to the intermediate gland portion 16 is high, the cooling steam supply adjustment valve 21 and the steam recovery adjustment valve 25. The high-temperature steam is sucked in at the suction port 24 of the intermediate gland part 16 and more cooling steam is ejected at the jet port 22 so that the cooling steam is brought to an appropriate temperature over the entire load operation. Since it supplies to balance hole 19a, 19b, wheel 18a, 18b can be cooled favorably.

  Thus, this embodiment branches from the low-temperature reheat steam pipe 20 of the high-pressure turbine exhaust chamber 10, and is connected to the jet outlet 22 of the intermediate ground portion 16 via the cooling steam supply adjustment valve 21 on the way. A high-pressure turbine exhaust chamber is provided with a cooling steam supply pipe 26 and a steam recovery pipe 27 connected to the low-temperature reheat steam pipe 20 from the suction port 24 of the intermediate gland 16 and a steam recovery adjustment valve 25 in the middle. The high pressure turbine exhaust from 10 is supplied as cooling steam to the medium pressure turbine first stage 14a and the second stage balance holes 19a and 19b of the intermediate pressure turbine section 3 to cool the wheels 18a and 18b, and the high pressure turbine nozzle box When a part of the steam supplied from 5 to the first stage 9a of the high-pressure turbine and finished the expansion work is inverted and the temperature of the inverted steam is high, the suction port 24 of the intermediate gland part 16 The high temperature guarantee is maintained even if reheat steam having a temperature of 650 ° C. or higher is supplied to the medium pressure turbine section 3 having a high and medium pressure integrated structure. It is possible to increase the temperature of the intermediate pressure turbine section 3 by applying a ferritic material having a proven record in the past to the turbine rotor 6, the turbine nozzles 12, 12a, 12b, the turbine blades 13, 13a, 13b, and the like as they are. Inverted steam from the high pressure turbine nozzle box 5 can be effectively recovered.

  2 and 3 are partially cutaway, partially broken schematic longitudinal sectional views showing a second embodiment of the steam turbine plant according to the present invention. In addition, in the figure, FIG. 2 shows the whole general | schematic longitudinal cross-section, and FIG. 3 shows the partial expansion of the A section of FIG.

  The steam turbine plant according to the present embodiment branches the extraction pipe 28 connected to the feed water heater (not shown) from the high-pressure turbine final stage 9b of the high-pressure turbine section 2 and passes the adjustment valve 21 for cooling steam supply on the way. And connected to the outlet side of the check valve 26 of the extraction pipe 28 from the suction port 24 of the intermediate gland part 16 and the cooling steam supply pipe 23 connected to the jet outlet 22 of the intermediate gland part 16. A steam recovery pipe 27 with a control valve 25 is provided.

  Since the other constituent elements are the same as the constituent elements of the first embodiment, only the same reference numerals are given, and redundant description is omitted.

  As shown in FIG. 3, the steam turbine plant having a high-medium pressure integrated structure having such a configuration has an intermediate ground through the outside of the high-pressure turbine nozzle box 5 with the steam inverted from the high-pressure turbine first stage 9 a of the high-pressure turbine section 2. The combined steam is caused to flow into the balance hole 19a of the intermediate pressure turbine first stage 14a of the intermediate pressure turbine section 3 by flowing into the section 16 where it is combined with the cooling steam ejected from the cooling steam supply pipe 23 to the ejection port 22 of the intermediate ground section 16. Supply and cool the wheel 18a. When the temperature of the reversing steam flowing outside the high-pressure turbine nozzle box 5 is high, the steam recovery pipe 27 collects the reverse steam through the suction port 24 of the intermediate gland portion 16.

  Thus, this embodiment supplies the extraction steam extracted from the periphery of the high-pressure turbine final stage 9b of the high-pressure turbine section 2 as cooling steam to the wheel 18 or the like of the intermediate-pressure turbine section 3 to cool the wheel 18 or the like. Because of the construction, high strength assurance is maintained even when reheat steam at a temperature of 650 ° C. or higher is supplied to the medium pressure turbine section 3 having a high and medium pressure integrated structure, and a ferritic material that has been proven in the past. Can be applied to turbine components such as the turbine rotor 6 as they are to increase the temperature of the intermediate pressure turbine section 3.

  4 and 5 are partially cutaway and partially broken schematic longitudinal sectional views showing a third embodiment of the steam turbine plant according to the present invention. 4 shows an overall schematic longitudinal section, and FIG. 5 shows a partial enlargement of a portion B in FIG.

  The steam turbine plant according to the present embodiment is connected to the outer peripheral side of the high-pressure turbine nozzle box 5 of the high-pressure turbine section 2 from an intermediate portion of the superheater 28 of the boiler 29 and is provided with a regulating valve 32 in the middle. It is equipped with.

  Since the other constituent elements are the same as the constituent elements of the first embodiment, only the same reference numerals are given, and redundant description is omitted.

  The steam turbine plant having a high-medium pressure integrated structure having such a configuration cools superheated steam extracted from an intermediate portion of the superheater 30 of the boiler 29 (this steam may be extracted from the inlet side of the superheater 30). As shown in FIG. 5, the steam is supplied from the cooling steam supply pipe 31 to the high-pressure turbine nozzle box 5 of the high-pressure turbine section 2, and after cooling the high-pressure turbine nozzle box 5, the intermediate-pressure turbine passes through the intermediate gland section 16. The intermediate pressure turbine first stage 14a of the section 3 and the intermediate pressure turbine second stage balance holes 19a and 19b are sequentially supplied to cool the wheels 18a and 18b.

  As described above, in the present embodiment, the superheated steam extracted from the intermediate portion or the inlet side of the superheater 30 of the boiler 29 is used as the cooling steam, and the outside of the high pressure turbine nozzle box 5 of the high pressure turbine section 2 through the cooling steam supply pipe 31. After the high pressure turbine nozzle box 5 is cooled, the wheels 18a and 18b of the intermediate pressure turbine section 3 are sequentially cooled through the intermediate gland section 16, so that the intermediate pressure turbine section 3 having a high and intermediate pressure integrated structure is provided. Even if reheat steam having a temperature of 650 ° C. or higher is supplied, a high strength guarantee is maintained, and a ferritic material having a proven record in the past is applied to turbine components such as the turbine rotor 6 as it is, so that the intermediate pressure turbine section 2 The temperature can be increased.

  In the present embodiment, the superheated steam extracted from the superheater 30 of the boiler 29 is supplied as the cooling steam to the outside of the high-pressure turbine nozzle box 5 of the high-pressure turbine section 2, but the present invention is not limited to this example. As shown in FIG. 3, superheated steam from the intermediate part or inlet side of the superheater 30 of the boiler 29 is transferred from the jet port 22 of the intermediate ground part 16 to the high pressure turbine nozzle box 5 side of the high pressure turbine part 2 and the intermediate pressure turbine part 3. The intermediate pressure turbine first stage 14a and the intermediate pressure turbine second stage may be divided into the respective wheels 18a and 18b.

1 is a partially cutaway, partially broken schematic longitudinal sectional view showing a first embodiment of a steam turbine plant according to the present invention. The partially notched and partially broken schematic longitudinal cross-sectional view which shows 2nd Embodiment of the steam turbine plant which concerns on this invention. The elements on larger scale of the A section of FIG. The partially cutaway and partially broken schematic longitudinal sectional view showing a third embodiment of the steam turbine plant according to the present invention. The elements on larger scale of the B section of FIG. The partially notched and partially broken schematic longitudinal cross-sectional view which shows 4th Embodiment of the steam turbine plant which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine casing 2 High pressure turbine part 3 Medium pressure turbine part 4 Main steam pipe 5 High pressure turbine nozzle box 6 Turbine rotor 7, 7a, 7b Turbine nozzle 8, 8a, 8b Turbine blade 9 High pressure turbine stage 9a High pressure turbine first stage 9b High pressure Turbine final stage 10 High-pressure turbine exhaust chamber 11 Medium-pressure turbine nozzle box 12, 12a, 12b Turbine nozzles 13, 13a, 13b Turbine blades 14 Medium-pressure turbine stage 14a Intermediate-pressure turbine first stage 14b Intermediate-pressure turbine final stage 15 Medium-pressure turbine Exhaust chamber 16 Intermediate ground portion 17 Reheat steam pipes 18a and 18b Wheels 19a and 19b Balance hole 20 Low temperature reheat steam pipe 21 Cooling steam supply adjustment valve 22 Outlet 23 Cooling steam supply pipe 24 Suction port 25 Steam recovery adjustment valve 26 Check valve 27 Steam recovery pipe 28 Trachea 29 boiler 30 superheater 31 cooling steam supply pipe 32 regulating valve

Claims (13)

In a steam turbine plant having a high-medium pressure integrated structure in which a high-pressure turbine section and an intermediate-pressure turbine section are accommodated in a single turbine casing, steam reversed from the outlet of the first stage of the high-pressure turbine of the high-pressure turbine section is supplied to a high-pressure turbine nozzle box and When supplying to the wheel of the first stage of the intermediate pressure turbine in the intermediate pressure turbine section through the intermediate ground portion provided across the high pressure turbine section and the intermediate pressure turbine section, the first stage of the high pressure turbine of the high pressure turbine section A steam turbine plant characterized in that a cooling steam supply means for supplying and mixing cooling steam to the inverted steam from the outlet is provided in the intermediate ground portion. 2. The steam turbine plant according to claim 1, wherein the cooling steam supply means is a cooling steam supply pipe, and the cooling steam supply pipe is connected to an extraction pipe provided in a high-pressure turbine stage of the high-pressure turbine section. . The steam turbine plant according to claim 2, wherein the extraction pipe is provided in a final stage of the high-pressure turbine in the high-pressure turbine section. The cooling steam supply means is a cooling steam supply pipe, and the cooling steam supply pipe is connected to a low temperature reheat steam pipe provided in a high pressure turbine exhaust chamber of the high pressure turbine section. Steam turbine plant. In a steam turbine plant having a high-medium pressure integrated structure in which a high-pressure turbine section and an intermediate-pressure turbine section are accommodated in a single turbine casing, steam reversed from the outlet of the first stage of the high-pressure turbine of the high-pressure turbine section is supplied to a high-pressure turbine nozzle box and When supplying to the wheel of the first stage of the intermediate pressure turbine in the intermediate pressure turbine section through the intermediate ground portion provided across the high pressure turbine section and the intermediate pressure turbine section, the first stage of the high pressure turbine of the high pressure turbine section A steam recovery means for extracting a part of the steam inverted from the outlet is provided in the intermediate gland part, and a cooling steam supply means for supplying and mixing the cooling steam to the remaining steam is provided in the intermediate gland part. A steam turbine plant. 6. The steam turbine plant according to claim 5, wherein the steam recovery means is a steam recovery pipe, and the steam recovery pipe is connected to an extraction pipe provided in a high-pressure turbine stage of the high-pressure turbine section. 6. The steam turbine according to claim 5, wherein the steam recovery means is a steam recovery pipe, and the steam recovery pipe is connected to a low temperature reheat steam pipe provided in a high pressure turbine exhaust chamber of the high pressure turbine section. plant. The steam turbine plant according to claim 1, wherein the cooling steam supply means includes a cooling steam supply adjusting valve that is controlled to open and close in accordance with load fluctuations. The steam turbine plant according to claim 5, wherein the steam recovery means includes a steam recovery adjustment valve that is controlled to open and close in accordance with a load fluctuation. In a steam turbine plant having a high and intermediate pressure integrated structure in which a high pressure turbine section and an intermediate pressure turbine section are accommodated in one turbine casing, the high pressure turbine section and the intermediate pressure turbine are provided from the outside of the high pressure turbine nozzle box provided in the high pressure turbine section. The high-pressure turbine nozzle box is provided with cooling steam supply means for supplying cooling steam to a wheel of an intermediate-pressure turbine stage in the intermediate-pressure turbine section through an intermediate ground portion provided across the section. Turbine plant. In a steam turbine plant having a high-medium pressure integrated structure in which a high-pressure turbine portion and an intermediate-pressure turbine portion are accommodated in a single turbine casing, the high-pressure turbine portion and the intermediate-pressure turbine portion are provided with the high-pressure from an intermediate ground portion provided across the high-pressure turbine portion and the intermediate-pressure turbine portion. Cooling steam supply means for supplying cooling steam by diverting to each of the high pressure turbine nozzle box provided in the turbine section and the wheel of the intermediate pressure turbine stage in the intermediate pressure turbine section is provided in the intermediate ground section. Steam turbine plant. The steam turbine plant according to claim 10 or 11, wherein the cooling steam supply means is a cooling steam supply pipe, and the cooling steam supply pipe is connected to an intermediate portion of a superheater of the boiler. The steam turbine plant according to claim 10 or 11, wherein the cooling steam supply means is a cooling steam supply pipe, and the cooling steam supply pipe is connected to an inlet side of a superheater of the boiler.

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