TW202417731A - Steam turbine and modification method thereof - Google Patents

Abstract

In the steam turbine modification method, a wing removal project and a flow path separation project are performed. In the wing removal project, a plurality of rows of movable wing rows, including the movable wing row closest to the downstream side of the axis and adjacent to each other in the axial direction, are removed from among the plurality of rows of movable wing rows, and the stationary wing rows adjacent to the axial upstream side of the movable wing rows of the plurality of removed movable wing rows are removed from among the plurality of stationary wing rows. In the flow path separation project, the movable wing row closest to the downstream side of the axis, i.e., the last section of the movable wing row still close to the downstream side of the axis, among the one or more rows of movable wing rows remaining after the wing removal project, is separated from the annular steam flow path formed between the inner circumference of the rotor case and the outer circumference of the rotor shaft.

Description

Steam turbine and modification method thereof

The present invention relates to a steam turbine and a method for modifying the same.

Steam turbine equipment usually includes: a boiler, a steam turbine driven by steam from the boiler, a generator that generates electricity driven by the steam turbine, and a condenser that converts the steam exhausted from the steam turbine back into water.

For example, the following patent document 1 discloses a method for modifying a steam turbine device for effectively utilizing the heat of steam generated by a boiler. The steam turbine device before modification of the patent document 1 comprises: a high-pressure steam turbine driven by steam from a boiler, a low-pressure steam turbine driven by steam exhausted from the high-pressure steam turbine, a generator for generating electricity by driving the high-pressure steam turbine and the low-pressure steam turbine, and a condenser for converting steam exhausted from the low-pressure steam turbine back into water. The technology described in the patent document 1 is to modify the steam turbine equipment so that the steam exhausted from the high-pressure steam turbine is not directed to the low-pressure steam turbine, but the steam is directed to other steam utilization equipment as working steam. In this technology, since the steam is not directed to the low-pressure steam turbine, the power generation of the generator will decrease, but there will be no heat loss in the process of converting steam back to water in the condenser, so the heat from the steam of the old boiler can be effectively utilized. [Prior technical document] [Patent document]

[Patent Document 1] Japanese Patent Application Publication No. 2006-002696

[The problem the invention is trying to solve]

Although the technology described in the above-mentioned patent document 1 can effectively utilize the heat of the steam from the boiler, the pressure and temperature of the steam sent to the steam utilization equipment are conditional. Therefore, the technology described in the above-mentioned patent document 1 may not be able to supply steam with the desired pressure and temperature to the steam utilization equipment.

Therefore, the present invention aims to provide a steam turbine modification method and a steam turbine obtained by performing the modification method, which can deliver steam with the pressure and temperature desired by the steam utilization side to the steam utilization equipment. [Technical means for solving the problem]

A steam turbine modification method in one form of the invention for achieving the above-mentioned purpose is based on the following steam turbine. The steam turbine comprises: a rotor that can rotate around an axis, a rotor shell covering the outer circumference of the rotor, and a plurality of rows of stationary wing rows arranged on the inner circumference of the rotor shell and arranged in parallel in the axial direction extending from the axis. The rotor comprises: a rotor shaft centered on the axis and extending in the axial direction, and a plurality of rows of movable wing rows arranged on the rotor shaft. The plurality of rows of movable wing rows are respectively arranged on the downstream side of the axis in the axial direction of any row of stationary wing rows among the plurality of rows of stationary wing rows. In the steam turbine modification method, a wing removal process is performed, wherein among the plurality of rows of movable wing rows, a plurality of rows of movable wing rows that are adjacent to each other in the axis direction and include the movable wing row closest to the axis downstream, or the movable wing row closest to the axis downstream, are removed, and among the plurality of rows of stationary wing rows, one or more rows of movable wing rows are removed, and the stationary wing rows adjacent to the axis upstream in the axis direction of the movable wing rows are removed, and the plurality of rows of movable wing rows are removed. In the above-mentioned wing removal process, at least the active wing row closest to the upstream side of the aforementioned axis is retained, and among the aforementioned multiple rows of stationary wing rows, at least the stationary wing row closest to the upstream side of the aforementioned axis is retained; and a flow path separation process, which separates the annular steam flow path formed between the inner circumference of the aforementioned rotor shell and the outer circumference of the aforementioned rotor shaft at a position closer to the downstream side of the aforementioned axis than the active wing row closest to the downstream side of the aforementioned axis among the one or more active wing rows retained after the aforementioned wing removal process, i.e., the final section active wing row.

In this embodiment, the steam from the steam turbine is not sent to the condenser, but the steam in the upstream space on the side of the last moving wing row than the position where the steam flow path is divided is sent to the steam utilization equipment. Therefore, in this embodiment, there is no heat loss in the process of converting steam back to water in the condenser, and the heat of the steam from the boiler can be effectively used.

Furthermore, in this aspect, the wing row sections to be removed can be appropriately selected, thereby allowing steam with a pressure and temperature that meets the desired requirements of the steam utilization side to be delivered to the steam utilization equipment.

A steam turbine in one aspect of the invention for achieving the above-mentioned purpose comprises: a rotor rotatable about an axis, a rotor shell covering the outer circumference of the rotor, one or more rows of stationary wing rows arranged on the inner circumference of the rotor shell and arranged in parallel in the axial direction in which the axis extends, a partition plate for dividing a steam flow path, and an exhaust flow path forming portion forming an exhaust flow path that can guide steam to the outside of the rotor shell. The rotor comprises: a rotor shaft centered about the axis and extending in the axial direction, and one or more rows of movable wing rows arranged on the rotor shaft. One or more rows of movable wing rows are respectively arranged on the axial downstream side of any one row of stationary wing rows among the one or more rows of stationary wing rows in the axial direction. The aforementioned steam flow path is an annular flow path formed between the inner circumference of the aforementioned rotor shell and the outer circumference of the aforementioned rotor shaft. The aforementioned partition plate is located at a position closer to the downstream side of the aforementioned axis than the movable wing row closest to the downstream side of the aforementioned axis among more than one row of movable wing rows, that is, the final movable wing row. The aforementioned exhaust flow path can guide the steam in the space on the side of the aforementioned final movable wing row than the position where the aforementioned steam flow path is divided to the outside of the aforementioned rotor shell. [Effect of the invention]

According to one aspect of the present invention, steam having a pressure and a temperature that meet the requirements of the steam utilization side can be delivered to the steam utilization equipment.

Hereinafter, the steam turbine modification method of the present invention, and the implementation forms and variations of the steam turbine obtained by performing the modification method will be described in detail with reference to the drawings.

"First Implementation Form" Referring to Figures 1 to 4, the steam turbine modification method of the first implementation form and the steam turbine obtained by performing the modification method are explained.

First, a steam turbine before modification will be described with reference to Fig. 1. The steam turbine 10 before modification includes a high-pressure steam turbine section 20 and a low-pressure steam turbine section 50.

The high-pressure steam turbine unit 20 includes a high-pressure rotor 21 that can rotate about an axis Ar, a high-pressure rotor casing 30 that covers the outer periphery of the high-pressure rotor 21, a plurality of stationary blade rows 36, a high-pressure steam pipe 40, a high-pressure steam valve 41, a high-pressure shaft seal device 42, and an intermediate shaft seal device 43.

Here, the extending direction of the axis Ar is defined as the axis direction Da, one side of the axis direction Da is defined as the axis upstream side Dau, and the other side of the axis direction Da is defined as the axis downstream side Dad. Furthermore, the direction perpendicular to the axis Ar is defined as the radial direction Dr, the side of the radial direction Dr approaching the axis Ar is defined as the radial direction inner side Dri, and the side of the radial direction Dr away from the axis Ar is defined as the radial direction outer side Dro. In addition, the circumferential direction with respect to the axis Ar is simply defined as the circumferential direction Dc.

The high-pressure rotor 21 has a high-pressure rotor shaft 22 centered on the axis Ar and extending in the axial direction Da, and a plurality of rows of movable wing rows 25 provided on the high-pressure rotor shaft 22. The high-pressure steam turbine section 20 of this embodiment has four rows of movable wing rows 25. The plurality of rows of movable wing rows 25 are arranged side by side in the axial direction Da with spaces between them. The plurality of rows of movable wing rows 25 each have a plurality of movable wings 26 arranged side by side in the circumferential direction Dc. The movable wing 26 has a wing body 27 having a wing-shaped cross section and extending in a radial direction Dri perpendicular to the cross section, and a wing root 28 provided on the radial inner side Dri of the wing body 27. The high-pressure rotor shaft 22 is provided with a movable row mounting portion 23, to which the blade roots 28 of a plurality of movable blades 26 constituting the movable row 25 are mounted. The movable row mounting portion 23 is an annular groove that is recessed from the outer periphery of the high-pressure rotor shaft 22 toward the inner side in the radial direction Dri.

The plurality of rows of static wing rows 36 are respectively arranged at the axis upstream side Dau of any row of movable wing rows 25 among the plurality of rows of movable wing rows 25. Therefore, the high-pressure steam turbine section 20 of the present embodiment has four rows of static wing rows 36. That is, the high-pressure steam turbine section 20 of the present embodiment has four rows of wing rows. Moreover, one row of wing rows is composed of one row of static wing rows 36 and one row of movable wing rows 25. The plurality of rows of static wing rows 36 all have a plurality of wing bodies 37 arranged side by side in the circumferential direction Dc, and an annular outer ring 38 and an inner ring 39 centered on the axis Ar. The wing body 37 has a wing-shaped cross section, extending in a radial direction Dr perpendicular to the cross section. The outer ring 38 connects the radially outer ends of the plurality of wing bodies 37 arranged in parallel in the circumferential direction Dc to each other. The inner ring 39 connects the radially inner ends of the plurality of wing bodies 37 arranged in parallel in the circumferential direction Dc to each other. The high-pressure rotor shell 30 is formed with a stationary wing row mounting portion 32, to which each of the plurality of stationary wing rows 36 is mounted. The stationary wing row mounting portion 32 is an annular groove recessed from the inner circumferential surface of the high-pressure rotor shell 30 toward the radially outer side Dro.

In the high-pressure rotor case 30, a high-pressure steam pipe 40 is connected to a position closer to the axial upstream side Dau than the stationary wing row 36 closest to the axial upstream side Dau among the plurality of stationary wing rows 36. A high-pressure steam valve 41 is provided in the high-pressure steam pipe 40. In the high-pressure rotor case 30, a high-pressure steam exhaust port 33 is formed closer to the axial downstream side Dad than the movable wing row 25 closest to the axial downstream side Dad among the plurality of movable wing rows 25. An annular space between the inner circumference of the high-pressure rotor shell 30 and the outer circumference of the high-pressure rotor shaft 22, which is axially downstream of the high-pressure steam pipe 40 and axially upstream of the high-pressure steam exhaust port 33, forms an annular high-pressure steam flow path 35 for the high-pressure steam from the high-pressure steam pipe 40 to flow.

In the high-pressure rotor shell 30, a high-pressure shaft seal device 42 is arranged on the axial upstream side Dau of the high-pressure steam pipe 40. The high-pressure shaft seal device 42 is a device for suppressing the high-pressure steam in the high-pressure rotor shell 30 from flowing out from between the high-pressure rotor shell 30 and the high-pressure rotor shaft 22. The high-pressure shaft seal device 42 has: a seal 42s facing the outer peripheral surface of the high-pressure rotor shaft 22, and a seal support platform 42b supporting the seal 42s. The seal 42s and the seal support platform 42b are both annular with the axis Ar as the center. The seal support platform 42b is connected to the inner peripheral surface of the high-pressure rotor shell 30.

In the high-pressure rotor shell 30, an intermediate shaft seal device 43 is arranged on the axial downstream side Dad of the high-pressure steam exhaust port 33. The intermediate shaft seal device 43 is a device for suppressing the high-pressure steam in the high-pressure rotor shell 30 from flowing out from between the high-pressure rotor shell 30 and the high-pressure rotor shaft 22. The intermediate shaft seal device 43 has: a seal 43s facing the outer peripheral surface of the high-pressure rotor shaft 22, and a seal support platform 43b supporting the seal 43s. The seal 43s and the seal support platform 43b are both annular with the axis Ar as the center. The seal support platform 43b is connected to the inner peripheral surface of the high-pressure rotor shell 30.

The low-pressure steam turbine section 50 is arranged on the axis downstream side Dad of the high-pressure steam turbine section 20. The low-pressure steam turbine section 50 includes a low-pressure rotor 51 rotatable about the axis Ar, a low-pressure rotor casing 60 covering the outer periphery of the low-pressure rotor 51, a plurality of rows of stationary blades 66, a low-pressure steam pipe 70, a low-pressure steam valve 71, a low-pressure shaft seal 72, and an exhaust casing 75.

The low-pressure rotor 51 has a low-pressure rotor shaft 52 centered on the axis Ar and extending in the axial direction Da, and a plurality of rows of movable wing rows 55 provided on the low-pressure rotor shaft 52. The low-pressure steam turbine unit 50 of this embodiment has seven rows of movable wing rows 55. The plurality of rows of movable wing rows 55 are arranged side by side in the axial direction Da with a gap between them. The plurality of rows of movable wing rows 55 each have a plurality of rows of movable blades 56 arranged side by side in the circumferential direction Dc. The movable blade 56 has a wing body 57 having a wing-shaped cross section and extending in a radial direction Dri perpendicular to the cross section, and a blade root 58 provided on the radial inner side Dri of the wing body 57. The low-pressure rotor shaft 52 is provided with a movable row mounting portion 53 to which the blade roots 58 of a plurality of movable blades 56 constituting the movable row 55 are mounted. The movable row mounting portion 53 is an annular groove that is recessed from the outer periphery of the low-pressure rotor shaft 52 toward the inner side Dri in the radial direction.

The plurality of rows of static wing rows 66 are respectively arranged on the axis upstream side Dau of any row of movable wing rows 55 among the plurality of rows of movable wing rows 55. Therefore, the low-pressure steam turbine section 50 of the present embodiment has seven rows of static wing rows 66. That is, the low-pressure steam turbine section 50 of the present embodiment has seven rows of wing rows. Moreover, one row of wing rows is composed of one row of static wing rows 66 and one row of movable wing rows 55. The plurality of rows of static wing rows 66 all have a plurality of wing bodies 67 arranged side by side in the circumferential direction Dc, and an annular outer ring 68 and an inner ring 69 centered on the axis Ar. The wing body 67 has a wing-shaped cross section, extending in a radial direction Dr perpendicular to the cross section. The outer ring 68 connects the radially outer ends Dro of the plurality of wing bodies 67 arranged in parallel in the circumferential direction Dc to each other. The inner ring 69 connects the radially inner ends Dri of the plurality of wing bodies 67 arranged in parallel in the circumferential direction Dc to each other.

The low-pressure rotor casing 60 includes a casing body 61 and a diffusion portion 64 .

The shell body 61 covers the outer periphery of the low-pressure rotor 51, that is, the portion where the plurality of rows of stationary wing rows 66 and the plurality of rows of movable wing rows 55 exist in the axial direction Da. In the shell body 61, one end of a low-pressure steam pipe 70 is connected to a position closer to the axial upstream side Dau than the stationary wing row 66 closest to the axial upstream side Dau among the plurality of rows of stationary wing rows 66. The other end of the low-pressure steam pipe 70 is connected to the high-pressure steam exhaust port 33 of the high-pressure rotor shell 30. Thus, the low-pressure steam pipe 70 forms a downstream side steam flow path 70p connected to the annular high-pressure steam flow path 35. A low-pressure steam valve 71 is provided in the low-pressure steam pipe 70. The low-pressure steam valve 71 can separate the downstream steam flow path 70p by being in a closed state. In the shell body 61, an exhaust port 63 is formed at a position substantially in the middle of the axial direction Da, which extends from the inner peripheral side of the shell body 61 to the outer peripheral side. Specifically, the exhaust port 63 is formed at a position between the second wing row segment and the third wing row segment in the axial direction Da among the seven rows of wing rows. One end of the first steam supply pipeline 96a is connected to the exhaust port 63 of the shell body 61. The other end of the first steam supply pipeline 96a is connected to the first steam utilization device 95a.

The diffusion part 64 is arranged on the axial downstream side Dad of the shell body 61. The diffusion part 64 is formed in an annular shape with respect to the axis Ar, and forms a space which gradually moves toward the radial outer side Dro as it moves toward the axial downstream side Dad. Steam flows into the annular space after passing through the movable wing row 55 closest to the axial downstream side Dad among the plurality of rows of movable wing rows 55. The diffusion part 64 has an outer diffusion part (or a steam guide part or a fluid guide part) 64o defining the edge of the radial outer side Dro of the annular space, and an inner diffusion part (or a tapered bearing) 64i defining the edge of the radial inner side Dri of the space. The outer diffusion portion 64o is formed into a ring shape in a cross section perpendicular to the axis Ar, and gradually expands in a radial direction to the outer side Dro toward the axis downstream side Dad. The end of the outer diffusion portion 64o on the axis upstream side Dau is connected to the end of the low-pressure rotor shell 60 on the axis downstream side Dad. The inner diffusion portion 64i is formed into a ring shape in a cross section perpendicular to the axis Ar, and gradually expands in a radial direction to the outer side Dro toward the axis downstream side Dad. The end of the inner diffusion portion 64i on the axis downstream side Dad is connected to the exhaust shell 75.

The exhaust casing 75 forms an exhaust space 76 into which the steam passing through the diffusion section 64 flows. The exhaust casing 75 has an exhaust port 77 for exhausting the steam in the exhaust space 76 toward the condenser 99.

An annular space between the inner circumference of the shell body 61 and the outer circumference of the low-pressure rotor shaft 52, and an annular space within the diffusion section 64, which is axially downstream of the low-pressure steam pipe 70 and axially upstream of the diffusion section 64, forms an annular low-pressure steam flow path 65 for the low-pressure steam from the low-pressure steam pipe 70 to flow.

A low-pressure shaft sealing device 72 is disposed on the inner peripheral side of the inner diffusion portion 64i. The low-pressure shaft sealing device 72 is a device for suppressing the low-pressure steam in the low-pressure rotor shell 60 from flowing out from between the low-pressure rotor shell 60 and the low-pressure rotor shaft 52. The low-pressure shaft sealing device 72 includes: a seal 72s facing the outer peripheral surface of the low-pressure rotor shaft 52, and a seal support platform 72b supporting the seal 72s. The seal 72s and the seal support platform 72b are both annular with the axis Ar as the center. The seal support platform 72b is connected to the inner peripheral surface of the inner diffusion portion 64i of the low-pressure rotor shell 60.

The high-pressure rotor 21 and the low-pressure rotor 51 are located on the same axis Ar and are connected to each other to form the steam turbine rotor 11. The high-pressure rotor housing 30, the low-pressure rotor housing 60 and the exhaust housing 75 are connected to each other to form the steam turbine housing 15. The end of the axial upstream side Dau of the steam turbine rotor 11 protrudes from the inside of the steam turbine housing 15 to the axial upstream side Dau. In addition, the end of the axial downstream side Dad of the steam turbine rotor 11 protrudes from the inside of the steam turbine housing 15 to the axial downstream side Dad. The steam turbine 10 of this embodiment further includes a first bearing 16 and a second bearing 17 for rotatably supporting the steam turbine rotor 11. The first bearing 16 rotatably supports a portion of the steam turbine rotor 11 that protrudes from the steam turbine casing 15 to the upstream side of the axis Dau. The second bearing 17 rotatably supports a portion of the steam turbine rotor 11 that protrudes from the steam turbine casing 15 to the downstream side of the axis Dad.

Next, a modification method of the steam turbine 10 described above will be described according to the flow chart shown in FIG. 2 .

A request is received from a certain user to supply steam of a first pressure and a first temperature from the steam flowing in the steam turbine 10 before the modification described above. It is assumed that the steam passing through the fourth wing row section of the low-pressure steam turbine unit 50 is of the first pressure and the first temperature. In this case, as shown in FIG. 3 and FIG. 4 , the fourth wing row section of the low-pressure steam turbine unit 50 and all wing row sections on the axial upstream side Dau of the fourth wing row section are left, and all wing row sections on the axial downstream side Dad of the fourth wing row section are removed (wing removal process S1). Specifically, the static wing row 66 and the movable wing row 55 constituting the fifth wing row segment, the static wing row 66 and the movable wing row 55 constituting the sixth wing row segment, and the static wing row 66 and the movable wing row 55 constituting the seventh wing row segment closest to the axis downstream side Dad among the plurality of wing row segments are removed. As a result, the movable wing row 55 constituting the fourth wing row segment becomes the final movable wing row 55z of the modified steam turbine 10a.

Next, the annular low-pressure steam flow path 65 is divided at a position closer to the axis downstream side Dad than the final active wing row 55z using a partition plate 80 as a partition member (flow path partitioning process S2). The partition plate 80 has a partition plate body 81, an outer end 82, and an inner end 83. The partition plate body 81 is cylindrical with the axis Ar as the center, and the inner diameter gradually decreases toward the axis downstream side Dad. The outer end 82 is provided at the end of the partition plate body 81 on the outer side Dro in the radial direction and the end on the axis upstream side Dau. The outer peripheral end is annular with the axis Ar as the center. The inner end portion 83 is provided at the end of the radial inner side Dri of the partition plate body 81 and at the end of the axial downstream side Dad. The inner end portion 83 is annular with the axis Ar as the center. The inner end portion 83 has a partition plate seal 84 to seal between the partition plate 80 and the low-pressure shaft seal device 72. The annular outer end portion 82 is embedded in the annular groove, i.e., the stationary wing row mounting portion 62, and is mounted on the low-pressure rotor shell 60. The stationary wing row mounting portion 62 is a stationary wing row mounting portion on which the outer ring 68 of the stationary wing row 66 was once mounted among the multiple rows of stationary wing row mounting portions 62 of the low-pressure rotor casing 60. The stationary wing row 66 once constituted the fifth wing row segment removed by the wing removal process S1. The partition plate seal 84 of the annular inner end portion 83 contacts the seal support platform 72b of the annular low-pressure shaft seal device 72. The seal support platform 72b has an outer surface extending in the axial direction Da. The partition plate seal 84 contacts the outer surface of the seal support platform 72b so as to be movable relative to the seal support platform 72b in the axial direction Da.

In the present embodiment, the outer end 82 of the partition plate 80 is mounted on the stationary wing row mounting portion 62 formed on the low-pressure rotor casing 60 of the steam turbine 10 before modification. Therefore, modification of the low-pressure rotor casing 60 to which the outer end 82 of the partition plate 80 is mounted can be suppressed to a minimum. In addition, in the present embodiment, the outer end 82 of the partition plate 80 is embedded in the stationary wing row mounting portion 62, which is a groove recessed outward in the radial direction. Therefore, in the present embodiment, steam leakage between the low-pressure rotor casing 60 and the outer end 82 of the partition plate 80 can be suppressed.

Furthermore, in the present embodiment, the inner end portion 83 of the partition plate 80 is brought into contact with a stationary component having a portion along the outer peripheral surface of the low-pressure rotor shaft 52. Therefore, in the present embodiment, compared with a case where the inner end portion 83 of the partition plate 80 is brought into contact with a rotating component, it is possible to further suppress vapor leakage between the inner end portion 83 and the contact object.

The partition plate 80 expands in a direction including the radial direction Dr and the axial direction Da. As described above, the inner end portion 83 of the partition plate 80 can move in the axial direction Da with respect to the low-pressure shaft seal device 72. Therefore, the inner end portion 83 of the partition plate 80 can move in a direction including a component of the direction in which the partition plate 80 expands. Therefore, in this embodiment, even if the partition plate 80 is stretched due to heat, the extension of the partition plate 80 can be allowed by moving the inner end portion 83 of the partition plate 80.

In the present embodiment, the inner end portion 83 of the partition plate 80 is in contact with the low-pressure shaft seal 72, which is a stationary component. However, the inner end portion 83 of the partition plate 80 may be in contact with the inner diffuser 64i. In this case, the stationary components in contact with the inner end portion 83 include the low-pressure shaft seal 72 and the inner diffuser 64i.

Next, the exhaust flow path is set so that the steam in the upstream side space 65u on the side of the last stage active wing row 55z, which is closer to the position where the low-pressure steam flow path 65 is divided by the partition plate 80, can be guided to the outside of the low-pressure rotor shell 60 (exhaust flow path setting process S3). In the exhaust flow path setting process S3, an exhaust pipe (exhaust flow path forming portion) 85 forming the exhaust flow path is set. One end of the exhaust pipe 85 is connected to the partition plate 80, and the other end of the exhaust pipe 85 is connected to the second steam utilization device 95b that is the target of steam supply. Therefore, the exhaust pipe 85 becomes a second steam supply pipeline for sending the steam in the upstream side space 65u to the second steam utilization device 95b.

Next, the exhaust port 77 of the exhaust casing 75 is blocked by the blocking plate 86 (exhaust port blocking step S4). In the low-pressure steam flow path 65, a part of the steam in the upstream space 65u may flow into the downstream space 65d which is farther from the final active wing row 55z than the position where the low-pressure steam flow path 65 is divided by the partition plate 80, and may become drainage in the downstream space 65d. Therefore, it is preferable to provide a drainage discharge pipe 87 on the blocking plate 86 for discharging drainage from the exhaust space 76 connected to the downstream space 65d to the outside of the low-pressure steam turbine unit 50.

Next, a thermometer 93 capable of detecting the temperature of the downstream side space 65d and a spray nozzle 90 capable of spraying cooling water to the downstream side space 65d are installed (spray nozzle installation process S5). A cooling water pipeline 91 is connected to the spray nozzle 90. The cooling water pipeline 91 is provided with a regulating valve 92 capable of regulating the flow rate of cooling water flowing in the cooling water pipeline 91. The regulating valve 92 is opened when the temperature detected by the thermometer 93 is higher than a predetermined temperature. Here, the predetermined temperature is, for example, the design temperature of the exhaust casing 75. Therefore, if the temperature of the downstream side space 65d becomes higher than the design temperature of the exhaust casing 75, cooling water is sprayed from the spray nozzle 90 to the downstream side space 65d.

The steam temperature in the upstream side space 65u in the low-pressure steam flow path 65 is higher than the steam temperature of the active wing row 55 closest to the downstream side Dad of the steam turbine 10 before the modification. The steam pressure in the upstream side space 65u in the low-pressure steam flow path 65 is higher than the steam pressure of the active wing row 55 closest to the downstream side Dad of the steam turbine 10 before the modification. In addition, the design temperature and design pressure of the exhaust casing 75 are set in accordance with the steam temperature and pressure of the active wing row 55 closest to the downstream side Dad of the steam turbine 10 before the modification. Therefore, if part of the steam in the upstream space 65u flows into the downstream space 65d and the exhaust space 76, there is a possibility that the exhaust casing 75 or the low-pressure shaft seal device 72 may be damaged.

Therefore, in this embodiment, a spray nozzle 90 is provided that can spray cooling water into the downstream side space 65d. Even if a portion of the steam in the upstream side space 65u flows into the downstream side space 65d and the exhaust space 76, the temperature in the downstream side space 65d and the exhaust space 76 will not rise above a predetermined temperature, and the pressure in the downstream side space 65d and the exhaust space 76 will not rise above a predetermined pressure.

The above is the end of the modification of the steam turbine 10 of the present embodiment. Among the above processes, the exhaust flow path setting process S3, the exhaust port blocking process S4, and the spray nozzle installation process S5 can be performed at any stage. For example, the spray nozzle installation process S5 can be performed before the blade removal process S1.

The steam turbine 10a obtained by the modification described above lacks all the row sections that are closer to the axis downstream side Dad than the fourth row section of the low-pressure steam turbine section 50 before the modification. However, the steam turbine 10a obtained by the modification retains the stationary row mounting portion 62 for mounting the stationary row 66 constituting the removed row section and the movable row mounting portion 53 for mounting the movable row 55 constituting the removed row section. In addition, the steam turbine 10a obtained by the modification has a partition plate 80, a blocking plate 86, an exhaust pipe 85, and a spray nozzle 90 added to the steam turbine 10 before the modification.

As described above, in this embodiment, the steam from the steam turbine 10a is not sent to the condenser 99, but is sent to the second steam utilization device 95b. Therefore, there will be no heat loss in the process of converting the steam back into water in the condenser 99, and the heat of the steam from the boiler can be effectively utilized.

Furthermore, in this embodiment, the wing row sections to be removed can be appropriately selected, thereby allowing steam with the pressure and temperature desired by the steam utilization side to be delivered to the steam utilization equipment.

Furthermore, in this embodiment, a modification inside a shell can be used to deliver steam with a pressure and temperature that meets the desired requirements of the steam utilization side to the steam utilization equipment.

"Second Implementation Form" Referring to Figures 2, 5, and 6, the steam turbine modification method of the second implementation form and the steam turbine obtained by performing the modification method are explained.

The steam turbine before modification in this embodiment uses the steam turbine 10 described in FIG. 1 .

The modification method of the steam turbine 10 of this embodiment is described according to the flow chart shown in FIG. 2 .

A request is received from a certain user to supply steam of a second pressure and a second temperature from the steam flowing in the steam turbine 10 before modification. It is assumed that the steam passing through the second wing row section of the low-pressure steam turbine unit 50 is of the second pressure and the second temperature. In this case, as shown in FIG. 5 and FIG. 6 , the second wing row section of the low-pressure steam turbine unit 50 and all wing row sections on the axis upstream side Dau of the second wing row section are left, and all wing row sections on the axis downstream side Dad of the second wing row section are removed (wing removal process S1). Specifically, the static wing row 66 and the movable wing row 55 constituting the third wing row segment, the static wing row 66 and the movable wing row 55 constituting the fourth wing row segment, the static wing row 66 and the movable wing row 55 constituting the fifth wing row segment, the static wing row 66 and the movable wing row 55 constituting the sixth wing row segment, and the static wing row 66 and the movable wing row 55 constituting the seventh wing row segment closest to the axis downstream side Dad among the plurality of wing row segments are removed. As a result, the movable wing row 55 constituting the second wing row segment becomes the final movable wing row 55z of the modified steam turbine 10b.

Next, the annular low-pressure steam flow path 65 is divided at a position closer to the axis downstream side Dad than the final active wing row 55z using a partition plate 80a as a partition member (flow path partitioning process S2). The partition plate 80a of this embodiment also has: a partition plate body 81a, an outer end 82a, and an inner end 83a, similar to the partition plate 80 of the first embodiment. The partition plate body 81a is cylindrical with the axis Ar as the center, and the inner diameter gradually decreases toward the axis downstream side Dad. The outer end 82a is provided at the end of the partition plate body 81a on the outer side Dro in the radial direction and the end on the axis upstream side Dau. The outer end 82a is annular with the axis Ar as the center. Furthermore, the inner end portion 83a is provided at the end portion of the partition plate body 81a on the inner side Dri in the radial direction and on the end portion on the downstream side Dad of the axis. The inner end portion 83a is annular with the axis Ar as the center. The inner end portion 83a is different from the inner end portion 83a of the partition plate 80a of the first embodiment, and has a partition plate seal 84a for sealing between the partition plate 80a and the low-pressure rotor shaft 52. The annular outer end portion 82a is embedded in the annular groove, i.e., the stationary wing row mounting portion 62, and is mounted on the low-pressure rotor shell 60. The stationary wing row mounting portion 62 is a stationary wing row mounting portion 62 on which the outer ring 68 of the stationary wing row 66 is mounted among the plurality of rows of stationary wing row mounting portions 62 of the low-pressure rotor case 60. The stationary wing row 66 constitutes the third wing row section removed in the wing removal process S1. The partition plate seal 84a of the annular inner end portion 83a contacts the outer peripheral surface of the low-pressure rotor shaft 52 so as to be movable in the axial direction Da with respect to the low-pressure rotor shaft 52.

The partition plate 80a of this embodiment also expands in a direction including the radial direction Dr and the axial direction Da. As described above, the inner end portion 83a of the partition plate 80a can move in the axial direction Da with respect to the low-pressure rotor shaft 52. Therefore, the inner end portion 83a of the partition plate 80a can move in a direction including a component of the direction in which the partition plate 80a expands. Therefore, even if the partition plate 80a is stretched due to heat, the extension of the partition plate 80a can be allowed by moving the inner end portion 83a of the partition plate 80a.

Next, the exhaust air passage is set so that the steam in the upstream side space 65u on the side of the last stage active wing row 55z than the position where the low-pressure steam passage 65 is divided by the partition plate 80a in the low-pressure steam passage 65 can be guided to the outside of the low-pressure rotor case 60 (exhaust air passage setting process S3a). As described above, the low-pressure rotor case 60 of the steam turbine 10 before the modification is provided with an exhaust port 63 at a position between the second wing row section and the third wing row section in the axial direction Da. The exhaust port 63 is a hole that can guide the steam in the upstream side space 65u on the side of the last stage active wing row 55z than the position where the low-pressure steam passage 65 is divided by the partition plate 80a to the outside of the low-pressure rotor case 60. As described above, the first steam supply line 96a for sending steam to the existing first steam utilization device 95a is connected to the exhaust port 63. In addition, in the exhaust flow path setting project S3a, the exhaust port 63 and a part of the first steam supply line 96a are set as a part of the exhaust flow path. In addition, in the exhaust flow path setting project S3a, the existing first steam supply line 96a and the new third steam utilization device 95c are connected by the third steam supply line 96c. Therefore, in this embodiment, the steam in the upstream side space 65u can be sent to the first steam utilization device 95a through the first steam supply line 96a, and sent to the third steam utilization device 95c through the first steam supply line 96a and the third steam supply line 96c. Therefore, in the present embodiment, the exhaust port 63, the first steam supply line 96a, and the third steam supply line 96c constitute an exhaust flow path forming portion.

Next, similarly to the first embodiment, the exhaust port 77 of the exhaust casing 75 is blocked with the blocking plate 86 (exhaust port blocking step S4).

Next, similarly to the first embodiment, a thermometer 93 capable of detecting the temperature of the downstream space 65d and a spray nozzle 90 capable of spraying cooling water to the downstream space 65d are installed (spray nozzle installation process S5). A cooling water pipeline 91 is connected to the spray nozzle 90. A regulating valve 92 capable of regulating the flow rate of cooling water flowing in the cooling water pipeline 91 is installed in the cooling water pipeline 91. The regulating valve 92 is opened when the temperature detected by the thermometer 93 is higher than a predetermined temperature.

The above is the end of the modification of the steam turbine 10 according to the present embodiment.

The steam turbine 10b obtained by the modification described above lacks all the row sections that are closer to the axis downstream side Dad than the second row section of the low-pressure steam turbine section 50 before the modification. However, the steam turbine 10b obtained by the modification retains the stationary row mounting portion 62 for mounting the stationary row 66 constituting the removed row section and the movable row mounting portion 53 for mounting the movable row 55 constituting the removed row section. In addition, the steam turbine 10b obtained by the modification has a partition plate 80a, a blocking plate 86, and a spray nozzle 90 added to the steam turbine 10 before the modification.

As described above, in this embodiment, like the first embodiment, the steam from the steam turbine 10b is not sent to the condenser 99, but is sent to the third steam utilization device 95c. Therefore, there will be no heat loss in the process of converting the steam back into water in the condenser 99, and the heat of the steam from the boiler can be effectively utilized.

In addition, in this embodiment, as in the first embodiment, the wing row sections to be removed can be appropriately selected, thereby allowing steam with the pressure and temperature desired by the steam utilization side to be delivered to the steam utilization equipment.

In this embodiment, in addition to the existing first steam utilization equipment 95a, steam is also delivered to the new third steam utilization equipment 95c. However, in the case where the steam flow rate is required to be increased from the existing first steam utilization equipment 95a side, almost all of the steam in the upstream space 65u described above can be delivered to the first steam utilization equipment 95a through the first steam supply pipeline 96a. In this case, it is not necessary to set the aforementioned third steam supply pipeline 96c in the exhaust flow path setting project S3a, and there is no actual operation of the exhaust flow path setting project S3a. Therefore, the exhaust flow path setting project S3a is not required in this case.

"Third Implementation Form" Referring to Figures 7 and 8, the modification method of the steam turbine of the third implementation form and the steam turbine obtained by executing the modification method are explained.

The steam turbine before modification in this embodiment uses the steam turbine 10 described in FIG. 1 .

A request is received from a certain user to supply steam of a third pressure and a third temperature from the steam flowing in the steam turbine 10 before modification. It is assumed that the steam passing through the third wing row section of the high-pressure steam turbine unit 20 is of the third pressure and the third temperature. In this case, as shown in FIG. 7 and FIG. 8 , the third wing row section of the high-pressure steam turbine unit 20 and all wing row sections on the axial upstream side Dau of the third wing row section are left, and all wing row sections on the axial downstream side Dad of the third wing row section are removed (wing removal process S1). Specifically, the stationary wing row 36 and the movable wing row 25 constituting the fourth wing row section are removed. In addition, the stationary wing row 66 and the movable wing row 55 constituting the full wing row section are removed from the low-pressure steam turbine section 50. As a result, the movable wing row 25 constituting the third wing row section becomes the final movable wing row 25z of the modified steam turbine 10c.

Next, the annular high-pressure steam flow path 35 is divided at a position closer to the axis downstream side Dad than the final stage active wing row 25z using a partition plate 80b as a partition member (flow path partitioning process S2). The partition plate 80b of this embodiment also has: a partition plate body 81b, an outer end 82b, and an inner end 83b, similar to the partition plate 80 of the first embodiment. The partition plate body 81b is cylindrical with the axis Ar as the center, and the inner diameter gradually decreases toward the axis downstream side Dad. The outer end 82b is provided at the end of the partition plate body 81b on the outer side Dro in the radial direction and the end on the axis upstream side Dau. The outer end 82b is annular with the axis Ar as the center. The inner end portion 83b is provided at the end of the radial inner side Dri of the partition plate body 81b and at the end of the axial downstream side Dad. The inner end portion 83b is annular with the axis Ar as the center. The inner end portion 83b has a partition plate seal 84b to seal between the partition plate 80b and the intermediate shaft seal device 43. The annular outer end portion 82b is embedded in the annular groove, i.e., the stationary wing row mounting portion 32, and is mounted on the high-pressure rotor casing 30. The stationary wing row mounting portion 32 is a stationary wing row mounting portion 32 on which the outer ring 38 of the stationary wing row 36 is mounted among the plurality of stationary wing row mounting portions 32 of the high-pressure rotor casing 30. The stationary wing row 36 constitutes the fourth wing row section removed by the wing removal process S1. The partition plate seal 84b of the annular inner end portion 83b can contact the seal support platform 43b of the intermediate shaft seal device 43 so as to be movable in the axial direction Da with respect to the intermediate shaft seal device 43.

In the present embodiment, the inner end 83b of the partition plate 80b is in contact with the stationary part, that is, the intermediate shaft seal 43. However, the inner end 83b of the partition plate 80b may be in contact with the vicinity of the portion of the high-pressure rotor casing 30 to which the intermediate shaft seal 43 is connected. In this case, the stationary parts in contact with the inner end 83b include the low-pressure shaft seal 72 and the high-pressure rotor casing 30.

The partition plate 80b of this embodiment also expands in the direction including the radial direction Dr and the axial direction Da. As described above, the inner end portion 83b of the partition plate 80b can be moved in the axial direction Da with respect to the intermediate shaft seal device 43. Therefore, the inner end portion 83b of the partition plate 80b can be moved in the direction including the direction component in which the partition plate 80b expands. Therefore, even if the partition plate 80b is stretched due to heat, the extension of the partition plate 80b can be allowed by moving the inner end portion 83b of the partition plate 80b.

Next, the exhaust flow path is set so that the steam in the upstream side space 35u on the side closer to the last-stage active wing row 25z than the position where the high-pressure steam flow path 35 is divided by the partition plate 80b in the high-pressure steam flow path 35 can be guided to the outside of the high-pressure rotor shell 30 (exhaust flow path setting process S3). In the exhaust flow path setting process S3, an exhaust pipe (exhaust flow path forming portion) 85b forming the exhaust flow path is set. One end of the exhaust pipe 85b is connected to the partition plate 80b, and the other end of the exhaust pipe 85b is connected to the fourth steam utilization device 95d that is the target of steam supply. Therefore, the exhaust pipe 85b becomes a fourth steam supply pipeline for sending the steam in the upstream side space 35u to the fourth steam utilization device 95d.

Next, similarly to the first embodiment, the exhaust port 77 of the exhaust housing 75 is blocked with a blocking plate 86 (exhaust port blocking process S4). In addition, in the exhaust port blocking process S4, a blind flange 88 is provided in the first steam supply line 96a connected to the exhaust port 63 of the low-pressure rotor housing 60, so that steam does not flow in the first steam supply line 96a. In addition, similarly to the blocking plate 86, a drainage pipe 89 is preferably provided in the blind flange 88.

Next, similarly to the first embodiment, a thermometer 93 capable of detecting the temperature of the downstream space 35d and a spray nozzle 90 capable of spraying cooling water to the downstream space 35d are installed (spray nozzle installation process S5). A cooling water pipeline 91 is connected to the spray nozzle 90. A regulating valve 92 capable of regulating the flow rate of cooling water flowing in the cooling water pipeline 91 is installed in the cooling water pipeline 91. The regulating valve 92 is opened when the temperature detected by the thermometer 93 is higher than a predetermined temperature.

The above is the end of the modification of the steam turbine 10 according to the present embodiment.

The steam turbine 10c obtained by the modification described above lacks all the row sections that are closer to the axis downstream side Dad than the third row section of the high-pressure steam turbine section 20 before the modification. However, the steam turbine 10c obtained by the modification retains the stationary row mounting parts 32, 62 for mounting the stationary row 36, 66 constituting the removed row sections, and the movable row mounting parts 23, 53 for mounting the movable row 25, 55 constituting the removed row sections. Moreover, the steam turbine 10c obtained by the modification has a partition plate 80b, a blocking plate 86, an exhaust pipe 85b, and a spray nozzle 90 added to the steam turbine 10 before the modification.

As described above, in this embodiment, like the first embodiment, the steam from the steam turbine 10c is not sent to the condenser 99, but is sent to the fourth steam utilization device 95d. Therefore, there will be no heat loss in the process of converting the steam back into water in the condenser 99, and the heat of the steam from the boiler can be effectively utilized.

In addition, in this embodiment, as in the first embodiment, the wing row sections to be removed can be appropriately selected, thereby allowing steam with the pressure and temperature desired by the steam utilization side to be delivered to the steam utilization equipment.

"Variation" The inner end portions 83, 83a, 83b of the partition plates 80, 80a, 80b of the above embodiments allow the partition plates 80, 80a, 80b to be extended in the direction including the radial direction Dr and the axial direction Da, so they can move in the axial direction Da. However, the inner end portions 83, 83a, 83b of the partition plates 80, 80a, 80b can move in any direction as long as it includes the radial direction Dr and the axial direction Da in which the partition plates 80, 80a, 80b are expanded. Therefore, the inner end portions 83, 83a, 83b of the partition plates 80, 80a, 80b can also move in the radial direction Dr.

In the second embodiment, the inner end 83a of the partition plate 80a is in contact with the low-pressure rotor shaft 52. However, the inner end 83a of the partition plate 80a may be in contact with a stationary component as in the first embodiment. In addition, in the first and third embodiments, the inner end 83, 83b of the partition plates 80, 80b are in contact with a stationary component. However, the inner end 83, 83b of the partition plates 80, 80b may be in contact with the rotor shafts 22, 52 as in the second embodiment.

In the first and third embodiments, the exhaust pipes 85 and 85b are connected to the partition plates 80 and 80b. However, as long as the steam in the upstream side space 35u and 65u can be guided to the outside of the rotor shell 30 and 60, the exhaust pipes 85 and 85b may not be connected to the partition plates 80 and 80b. For example, as shown in FIG. 9, a port 63x is provided in the low-pressure rotor shell 60 for exhausting the steam in the upstream side space 65u to the outside of the low-pressure rotor shell 60, and the exhaust pipe 85c may be connected to the port 63x. In addition, the low-pressure rotor shell 60 can discharge the steam in the upstream side space 65u to the port 63x outside the low-pressure rotor shell 60. For example, there is also a situation in which the steam generated in the upstream side space 65u is discharged in advance.

In the flow path partitioning step S2 of the third embodiment, the partition plate 80b is used as a partitioning member to partition the annular high-pressure steam flow path 35 at a position closer to the axis downstream side Dad than the last stage active wing row 25z. However, as shown in FIG10 , in the flow path partitioning step S2, the annular high-pressure steam flow path 35 is not partitioned by the partition plate 80b, but the downstream side steam flow path 70p connected to the high-pressure steam flow path 35 may be partitioned by closing the low-pressure steam valve 71. In this case, the low-pressure steam valve 71 serves as a partitioning member. In this case, instead of blocking the exhaust port 77 of the exhaust casing 75 with the blocking plate 86, the downstream side steam flow path 70p may be blocked with a blocking plate 86b at a position downstream of the position where the low-pressure steam valve 71 is provided in the downstream side steam flow path 70p in the steam flow direction. When the blocking plate 86b is provided in the downstream side steam flow path 70p, it is preferable to provide a drainage discharge pipe in the blocking plate 86b in the same manner as the blocking plate 86. In this case, a thermometer 93 may be provided in a space downstream of the low-pressure steam valve 71 and upstream of the blocking plate 86b in the downstream side steam flow path 70p, and a spray nozzle 90 that can spray cooling water into the space may be provided.

In each of the above embodiments, there is only one exhaust flow path that guides the steam in the upstream side space 35u, 65u to the outside of the rotor casing 30, 60. However, the exhaust flow path may be plural. For example, in the first embodiment, although one exhaust pipe 85 forming the exhaust flow path is connected to the partition plate 80, a plurality of exhaust pipes 85 may be connected to the partition plate 80. In this case, for example, when viewed from the axial direction, the exhaust pipes 85 are connected at the 3 o'clock position and the 9 o'clock position, respectively.

In the steam turbines 10a, 10b, 10c after the modification of the above-mentioned embodiments, the stationary wing row mounting parts 32, 62 and the movable wing row mounting parts 23, 53 are retained. The stationary wing row mounting parts 32, 62 were once mounted with the stationary wing row 36, 66 constituting the wing row section removed due to the modification, and the movable wing row mounting parts 23, 53 were once mounted with the movable wing row 25, 55 constituting the wing row section removed due to the modification. However, in the modification process, the portion of the stationary wing row mounting parts 32, 62 where the stationary wing row 36, 66 is not mounted may be removed from the rotor casing 30, 60. Furthermore, the portion of the movable wing row mounting parts 23, 53 where the movable wing row 25, 55 is not mounted may be removed from the rotor shaft 22, 52.

In the above embodiment, the exhaust port blocking process S4 and the spray nozzle installation process S5 are performed. However, the exhaust port blocking process S4 and the spray nozzle installation process S5 may be omitted. In particular, in the case of the third embodiment, as long as the low-pressure steam valve 71 is closed after the modification, the steam will hardly flow to the downstream side of the low-pressure steam valve 71, so the exhaust port blocking process S4 and the spray nozzle installation process S5 may also be omitted.

The present invention is not limited to the above-described embodiments. Various additions, changes, substitutions, and partial deletions may be made within the scope of the contents and equivalents specified in the patent application and within the scope of the conceptual thinking and gist of the present invention.

"Notes" The modification method of the steam turbine 10 of the above-mentioned embodiments and modifications can be grasped as follows, for example.

(1) The steam turbine modification method of the first mode is based on the steam turbine 10 described below. The steam turbine 10 to be modified comprises: a rotor 21, 51 rotatable about an axis Ar, a rotor case 30, 60 covering the outer circumference of the rotor 21, 51, and a plurality of rows of stationary wing rows 36, 66 arranged on the inner circumference of the rotor case 30, 60 and arranged in parallel in the axial direction Da extending from the axis Ar. The rotor 21, 51 comprises: a rotor shaft 22, 52 centered about the axis Ar and extending in the axial direction Da, and a plurality of rows of movable wing rows 25, 55 arranged on the rotor shaft 22, 52. The aforementioned multiple rows of active wing rows 25, 55 are respectively arranged at: the axial downstream side Dad of any row of static wing rows 36, 66 among the aforementioned multiple rows of static wing rows 36, 66 in the aforementioned axial direction Da. In the modification method of the steam turbine 10, a wing removal process S1 is performed, wherein among the plurality of rows of active wing rows 25, 55, the plurality of rows of active wing rows 25, 55 that are adjacent to each other in the axial direction Dad or the plurality of rows of active wing rows 25, 55 that are adjacent to each other in the axial direction Dad are removed, and among the plurality of rows of stationary wing rows 36, 66, at least one row of active wing rows 25, 55 that are adjacent to the axial upstream side Dau in the axial direction Da of the active wing rows 25, 55 are removed, and among the plurality of rows of stationary wing rows 36, 66, at least the plurality of rows of active wing rows 25, 55 that are adjacent to the axial upstream side Dau are removed. The active wing rows 25, 55 on the upstream side Dau, and at least the static wing rows 36, 66 closest to the upstream side Dau of the aforementioned axis are retained among the aforementioned multiple rows of static wing rows 36, 66; and the flow path separation process S2, which separates the annular steam flow path 35, 65 formed between the inner circumference of the aforementioned rotor shell 30, 60 and the outer circumference of the aforementioned rotor shaft 22, 52, or the downstream side steam flow path 70p connected to the aforementioned steam flow path 35 at the position of the active wing rows 25, 55 closest to the downstream side Dad of the aforementioned axis among the one or more active wing rows 25, 55 retained after the aforementioned wing removal process S1, that is, the final stage active wing rows 25z, 55z are closer to the downstream side Dad of the aforementioned axis.

In this embodiment, the steam from the steam turbine 10 can be sent to the condenser 99 instead of the steam flow paths 35 and 65 being divided, and the steam in the upstream space 35u and 65u on the side of the last stage active wing row 25z and 55z can be sent to the steam utilization equipment. Therefore, in this embodiment, there is no heat loss in the process of converting the steam back to water in the condenser 99, and the heat of the steam from the boiler can be effectively utilized.

Furthermore, in this aspect, the wing row sections to be removed can be appropriately selected, thereby allowing steam with the pressure and temperature that meet the steam utilization side's expectations to be delivered to the steam utilization equipment.

(2) A second embodiment of a steam turbine modification method, is a modification method of the steam turbine 10 of the first embodiment, wherein an exhaust flow path setting process S3 for setting an exhaust flow path is performed, which can guide the steam in the space on the side of the last stage active wing row 25z, 55z in the steam flow paths 35, 65, which is closer to the position where the steam flow paths 35, 65 or the downstream side steam flow paths 70p are separated, to the outside of the rotor casing 30, 60. In the exhaust flow path setting process S3, pipes 85, 85b forming the exhaust flow paths are provided.

(3) A third embodiment of a steam turbine modification method is a modification method of the steam turbine 10 of the first embodiment, wherein an exhaust port 63 is formed in advance in the rotor casing 60, which can guide steam in a space on the side of the final stage active wing row 25z, 55z than the position where the steam flow path 35, 65 or the downstream side steam flow path 70p is divided to the outside of the rotor casing 60. An exhaust flow path setting process S3a for setting an exhaust flow path is performed, which can guide steam in a space on the side of the final stage active wing row 55z than the position where the steam flow path 35, 65 or the downstream side steam flow path 70p is divided to the outside of the rotor casing 60. In the exhaust flow path setting process S3a, the exhaust port 63 is set as at least a part of the exhaust flow path.

(4) A fourth embodiment of a steam turbine modification method is a modification method for a steam turbine 10 of any one of the first to third embodiments, wherein the steam turbine 10 has a steam valve 71 that can separate the downstream steam flow path 70p. In the flow path separation step S2, the steam valve 71 is closed to separate the downstream steam flow path 70p.

(5) A fifth embodiment of a steam turbine modification method is a modification method for a steam turbine 10 of any one of the first to third embodiments, wherein in the flow path partitioning process S2, partition plates 80, 80a, 80b are used to partition the steam flow paths 35, 65. The partition plates 80, 80a, 80b have: inner end portions 83, 83a, 83b, which are ends of the radial inner side Dri of the radial direction Dr with respect to the axis Ar; and outer end portions 82, 82a, 82b, which are ends of the radial outer side Dro of the radial direction Dr. In the flow path partitioning process S2, the outer end portions 82, 82a, 82b of the partition plates 80, 80a, 80b are connected to the rotor casings 30, 60.

(6) A sixth embodiment of a steam turbine modification method is a modification method of the steam turbine 10 of the fifth embodiment, wherein in the flow path partitioning process S2, the outer end portions 82, 82a, 82b of the partition plates 80, 80a, 80b are connected to the stationary wing row mounting portions 32, 62, the stationary wing row mounting portions 32, 62 being the stationary wing rows 36, 66 closest to the upstream side Dau of the axis among the stationary wing rows 36, 66 removed by the wing removal process S1 and having been mounted in the rotor casing 30, 60.

In this embodiment, the outer ends 82, 82a, 82b of the partition plates 80, 80a, 80b are mounted on the stationary row mounting portions 32, 62 formed on the rotor casing 30, 60 of the steam turbine 10 before modification. Therefore, in this embodiment, modification of the rotor casing 30, 60 to which the outer ends 82b of the partition plates 80, 80a, 80b are mounted can be suppressed to a minimum.

(7) A seventh embodiment of a steam turbine modification method is a modification method of the steam turbine 10 of the fifth embodiment or the sixth embodiment, wherein the steam turbine 10 has a stationary part which is arranged at a position closer to the downstream side Dad of the axis than the last stage active wing row 25z, 55z and has a portion along the outer peripheral surface of the rotor shaft 22, 52. In the flow path partitioning process S2, the inner end portions 83, 83b of the partition plates 80, 80b are brought into contact with the stationary part.

In this embodiment, the inner end portions 83 and 83b of the partition plates 80 and 80b are brought into contact with a stationary component having a portion along the outer circumferential surface of the rotor shaft 22 and 52. Therefore, in this embodiment, compared with a case where the inner end portions 83 and 83b of the partition plates 80 and 80b are brought into contact with a rotating component, it is possible to further suppress vapor leakage between the inner end portions 83 and 83b and the contact object.

(8) The eighth aspect of the steam turbine modification method is the modification method of the steam turbine 10 of the seventh aspect, wherein, in the flow path partitioning step S2, the inner side ends 83, 83b of the partition plates 80, 80b are movable in a direction including a direction component in which the partition plates 80, 80b are expanded so that the inner side ends 83, 83b of the partition plates 80, 80b are in contact with the stationary parts.

In this embodiment, the inner end portions 83, 83b of the partition plates 80, 80b are brought into contact with the stationary part so that the inner end portions 83, 83b of the partition plates 80, 80b can move in a direction including a direction component in which the partition plates 80, 80b expand. Therefore, in this embodiment, even if the partition plates 80, 80b are extended by heat, the extension of the partition plates 80, 80b can be allowed by moving the inner end portions 83, 83b of the partition plates 80, 80b.

(9) A ninth embodiment of a steam turbine modification method, is a modification method of the steam turbine 10 of the seventh embodiment or the eighth embodiment, wherein the stationary parts are shaft seals 42, 43 facing the outer peripheral surface of the rotor shaft 22, 52 and capable of inhibiting steam from flowing out to the Dad on the downstream side of the shaft before itself.

(10) A tenth embodiment of a steam turbine modification method is a modification method of a steam turbine 10 of any one of the first to ninth embodiments, wherein the steam turbine 10 is provided with an exhaust casing 75 that can guide steam flowing from the steam flow path 65 to the condenser 99. An exhaust port blocking process S4 is performed to block the exhaust port 77 in the exhaust casing 75 for discharging steam from the condenser 99.

In this embodiment, even if a portion of the steam in the upstream space 65u which is closer to the final movable wing row 55z than the position where the steam flow path 65 is divided flows into the downstream space 65d which is farther from the final movable wing row 55z than the position where the steam flow path 65 is divided, the steam can be prevented from flowing into the condenser 99.

(11) The eleventh embodiment of the steam turbine modification method is a modification method of the steam turbine 10 of any one of the first embodiment to the tenth embodiment, wherein the mist nozzle installation process S5 of installing the mist nozzle 90 is performed, and cooling water can be sprayed from the space on the side farther from the last stage active wing row 25z, 55z than the position where the steam flow paths 35, 65 are separated in the steam flow paths 35, 65.

The steam temperature in the upstream side space 35u, 65u in the steam flow path 35, 65 is higher than the steam temperature in the active wing row 25, 55 closest to the axial downstream side Dad of the steam turbine 10 before the modification. The steam pressure in the upstream side space 35u, 65u in the steam flow path 35, 65 is higher than the steam pressure in the active wing row 25, 55 closest to the axial downstream side Dad of the steam turbine 10 before the modification. Therefore, if a part of the steam in the upstream side space 35u, 65u flows into the downstream side space 35d, 65d, there is a possibility that the downstream side space 35d, 65d or the shell for partitioning the downstream side space may be damaged. Therefore, in this embodiment, a spray nozzle 90 is provided to spray cooling water to the downstream side space 35d, 65d. Even if a part of the steam in the upstream side space 35u, 65u flows into the downstream side space 35d, 65d, the temperature in the downstream side space 35d, 65d will not rise above a predetermined temperature, and the pressure in the downstream side space 35d, 65d will not rise above a predetermined pressure.

The steam turbines 10a, 10b, and 10c after modification of the above-mentioned embodiments and modifications can be grasped as follows, for example.

(12) A steam turbine of the twelfth embodiment, comprising: a rotor 21, 51 rotatable about an axis Ar, a rotor shell 30, 60 covering the outer circumference of the rotor 21, 51, one or more rows of stationary wing rows 36, 66 arranged on the inner circumference of the rotor shell 30, 60 and arranged in parallel in the axial direction Da extending from the axis Ar, a partition member 80, 80a, 80b, 71 for partitioning a steam flow path 35, 65 or a downstream steam flow path 70p connected to the steam flow path 35, and an exhaust flow path forming portion for forming an exhaust flow path capable of guiding steam to the outside of the rotor shell 30, 60. The rotor 21, 51 comprises a rotor shaft 22, 52 extending in the axial direction Da with the axis Ar as the center, and one or more rows of movable wing rows 25, 55 provided on the rotor shaft 22, 52. The one or more rows of movable wing rows 25, 55 are respectively arranged on the axial downstream side Dad of any one row of the one or more rows of the stationary wing rows 36, 66 in the axial direction Da. The steam flow path 35, 65 is an annular flow path formed between the inner circumference of the rotor case 30, 60 and the outer circumference of the rotor shaft 22, 52. The partition members 80, 80a, 80b, 71 are used to separate the aforementioned steam flow path 35, 65 or the downstream side steam flow path 70p at a position closer to the aforementioned axis downstream side Dad than the movable wing row 25, 55 closest to the aforementioned axis downstream side Dad among more than one row of movable wing rows 25, 55, that is, the final stage movable wing row 25z, 55z. The aforementioned exhaust flow path can guide the steam in the space closer to the aforementioned final stage movable wing row 25z, 55z than the position where the aforementioned steam flow path 35, 65 or the downstream side steam flow path 70p is separated to the outside of the aforementioned rotor shell 30, 60.

(13) The thirteenth embodiment of the steam turbine is the steam turbine 10a, 10b, 10c of the twelfth embodiment, wherein the rotor casing 30, 60 has a stationary wing row mounting portion 32, 62 on the downstream side of the axis Dad of the final stage active wing row 25z, 55z, which can be mounted with the stationary wing row 36, 66 but does not have the stationary wing row 36, 66 mounted thereon. The rotor shaft 22, 52 has a moving wing row mounting portion 23, 53 on the downstream side of the axis Dad of the final stage active wing row 25z, 55z, which can be mounted with the moving wing row 25, 55 but does not have the moving wing row 25, 55 mounted thereon.

(14) A steam turbine of the fourteenth embodiment is the steam turbine 10a, 10b, 10c of the twelfth embodiment or the thirteenth embodiment, wherein the partition member 80, 80a, 80b, 71 has a steam valve 71 that can partition the downstream steam flow path 70p. The steam valve 71 is in a closed state when partitioning the downstream steam flow path 70p.

(15) A steam turbine of the fifteenth form is the steam turbine 10a, 10b, 10c of the twelfth form or the thirteenth form, wherein the partition member 80, 80a, 80b, 71 has a partition plate 80, 80a, 80b that can partition the steam flow path 35, 65. The partition plate 80, 80a, 80b has: an inner end 83, 83a, 83b, which is an end of the radial direction Dri in the radial direction Dr with respect to the axis Ar; and an outer end 82b, which is an end of the radial direction Dro in the radial direction Dr. The outer end 82b of the partition plate 80, 80a, 80b is connected to the rotor shell 30, 60.

(16) The steam turbine of the sixteenth embodiment is the steam turbine 10a, 10b, 10c described in the thirteenth embodiment, wherein the partition plates 80, 80a, 80b have: inner end portions 83, 83a, 83b, which are the ends of the radial inner side Dri in the radial direction Dr with respect to the axis Ar; and outer end portions 82b, which are the ends of the radial outer side Dro in the radial direction Dr. The outer end portions 82b of the partition plates 80, 80a, 80b are connected to the stationary wing row mounting portions 32, 62 of the rotor casings 30, 60.

(17) A steam turbine according to the seventeenth embodiment is the steam turbine 10a, 10c according to the fifteenth embodiment or the sixteenth embodiment, wherein the steam turbine 10a, 10c has a stationary part which is arranged at a position closer to the downstream side Dad of the axis than the last stage active wing row 25z, 55z and has a portion along the outer peripheral surface of the rotor shaft 22, 52. The inner end portions 83, 83b of the partition plates 80, 80b contact the stationary part.

(18) The steam turbine of the eighteenth embodiment is the steam turbine 10a, 10c of the seventeenth embodiment, wherein the inner end portions 83, 83b of the partition plates 80, 80b are in contact with the stationary part so that the inner end portions 83, 83b of the partition plates 80, 80b can move in a direction including a direction component in which the partition plates 80, 80b expand.

(19) The steam turbine of the nineteenth embodiment is the steam turbine 10a, 10c of the seventeenth embodiment or the eighteenth embodiment, wherein the stationary part is a shaft seal device 42, 43 facing the outer peripheral surface of the rotor shaft 22, 52 and capable of suppressing the outflow of steam to the Dad on the downstream side of the shaft before itself.

(20) A steam turbine of the twentieth embodiment is a steam turbine 10a, 10b, 10c of any one of the twelfth to nineteenth embodiments, wherein the steam turbine 10a, 10b, 10c comprises: an exhaust casing 75 that can discharge steam flowing through the steam flow paths 35, 65 to the condenser 99; and a plugging plate 86 that can block the exhaust port 77 in the exhaust casing 75 that can discharge steam from the condenser 99.

(21) A steam turbine of the twenty-first aspect, is a steam turbine 10a, 10b, 10c of any of the twelfth to twentieth aspects, wherein a spray nozzle 90 is provided to spray cooling water into the space on the side farther from the last-stage active wing row 25z, 55z than the partition plate 80, 80a, 80b in the steam flow path 35, 65. [Industrial Applicability]

According to one aspect of the present invention, steam having a pressure and a temperature that meet the requirements of the steam utilization side can be delivered to the steam utilization equipment.

10: Steam turbine (before modification) 10a, 10b, 10c: Steam turbine (after modification) 11: Steam turbine rotor 15: Steam turbine casing 16: First bearing 17: Second bearing 20: High-pressure steam turbine section 21: High-pressure rotor 22: High-pressure rotor shaft 23: Active wing row mounting section 25: Active wing row 25z: Final active wing row 26: Active wing 27: Wing body 28: Wing root 30: High-pressure rotor casing 32: Stationary wing row mounting section 33: High-pressure steam exhaust port 35: High-pressure steam flow path 35u: Upstream side space 35d: Downstream side space 36: Stationary wing row 37: Wing body 38: Outer ring 39: Inner ring 40: High-pressure steam pipe 41: High-pressure steam valve 42: High-pressure shaft sealing device 42s: Seal 42b: Seal support platform 43: Intermediate shaft sealing device 43s: Seal 43b: Seal support platform 50: Low-pressure steam turbine section 51: Low-pressure rotor 52: Low-pressure rotor shaft 53: Active wing row mounting section 55: Active wing row 55z: Final active wing row 56: Active wing 57: Wing body 58: Wing root 60: Low-pressure rotor casing 61: Casing body 62: Stationary wing row mounting part 63: Exhaust port 63x: Port 64: Diffuser 64o: Outer diffuser 64i: Inner diffuser 65: Low-pressure steam flow path 65u: Upstream space 65d: Downstream space 66: Stationary wing row 67: Wing body 68: Outer ring 69: Inner ring 70: Low-pressure steam pipe 70p: Downstream steam flow path 71: Low-pressure steam valve (partitioning member) 72: Low-pressure shaft sealing device 72s: Seal 72b: Sealing support platform 75: Exhaust shell 76: Exhaust space 77: Exhaust port 80,80a,80b: Partition plate (partition member) 81,81a,81b: Partition plate body 82,82a,82b: Outer end 83,83a,83b: Inner end 84,84a,84b: Partition plate seal 85,85b,85c: Exhaust pipe (exhaust flow path forming part) 86,86b: Blocking plate 87: Drainage discharge pipe 88: Blind flange 89: Drainage discharge pipe 90: Spray nozzle 91: Cooling water pipeline 92: Regulating valve 93: Thermometer 95a: First steam utilization equipment 96a: First steam supply pipeline 95b: Second steam utilization equipment 95c: Third steam utilization equipment 96c: Third steam supply pipeline 95d: Fourth steam utilization equipment 99: Condenser Ar: Axis Da: Axis direction Dau: Axis upstream side Dad: Axis downstream side Dc: Circumferential direction Dr: Radial direction Dri: Radial inner side Dro: Radial outer side

[Figure 1] A schematic cross-sectional view of a steam turbine before modification according to the first embodiment of the present invention. [Figure 2] A flow chart showing the modification method of the steam turbine according to the first and second embodiments of the present invention. [Figure 3] A schematic cross-sectional view of a steam turbine after modification according to the first embodiment of the present invention. [Figure 4] A cross-sectional view of the main part of the steam turbine after modification according to the first embodiment of the present invention. [Figure 5] A schematic cross-sectional view of a steam turbine after modification according to the second embodiment of the present invention. [Figure 6] A cross-sectional view of the main part of the steam turbine after modification according to the second embodiment of the present invention. [Figure 7] A schematic cross-sectional view of a steam turbine after modification according to the third embodiment of the present invention. [Figure 8] A cross-sectional view of the main parts of the steam turbine after modification of the third embodiment of the present invention. [Figure 9] A schematic cross-sectional view of the steam turbine after modification of the first embodiment of the present invention. [Figure 10] A schematic cross-sectional view of the steam turbine after modification of the third embodiment of the present invention.

Claims (21)

A method for modifying a steam turbine, comprising: a rotor rotatable about an axis, a rotor shell covering the outer periphery of the rotor, a plurality of rows of stationary wing rows arranged on the inner periphery of the rotor shell and arranged in parallel in the axial direction extending from the axis, the rotor having: a rotor axis centered about the axis and extending in the axial direction, and a plurality of rows of movable wing rows arranged on the rotor axis, the plurality of rows of movable wing rows being respectively arranged on the downstream side of the axis in the axial direction before any row of stationary wing rows among the plurality of rows of stationary wing rows, and characterized by performing: Wing removal engineering, including, among the aforementioned multiple rows of active wing rows, the multiple rows of active wing rows that are adjacent to each other in the aforementioned axial direction, or the active wing rows that are closest to the downstream side of the aforementioned axis are removed, and among the aforementioned multiple rows of static wing rows, removing more than one row of active wing rows, each of which is adjacent to the upstream side of the axis in the aforementioned axial direction of the active wing rows, at least the active wing row that is closest to the upstream side of the aforementioned axis is retained among the aforementioned multiple rows of active wing rows, and at least the static wing row that is closest to the upstream side of the aforementioned axis is retained among the aforementioned multiple rows of static wing rows; and The flow path separation process is to separate the annular steam flow path formed between the inner circumference of the rotor shell and the outer circumference of the rotor shaft or the downstream steam flow path connected to the steam flow path at the position of the active wing row closest to the downstream side of the axis among the one or more active wing rows retained after the wing removal process, i.e. the final active wing row, which is closer to the downstream side of the axis. A method for modifying a steam turbine as described in claim 1, wherein, an exhaust flow path setting project for setting an exhaust flow path is performed, which can guide the steam in the space on the side of the aforementioned final stage active wing row than the position where the aforementioned steam flow path or the aforementioned downstream side steam flow path is separated to the outside of the aforementioned rotor casing, in the aforementioned exhaust flow path setting project, a pipe forming the aforementioned exhaust flow path is provided. A method for modifying a steam turbine as described in claim 1, wherein, an exhaust port is formed in advance in the rotor shell, which can guide the steam in the space on the side of the last stage active wing row than the position where the steam flow path or the downstream side steam flow path is divided to the outside of the rotor shell, an exhaust flow path setting project for setting an exhaust flow path is performed, which can guide the steam in the space on the side of the last stage active wing row than the position where the steam flow path or the downstream side steam flow path is divided to the outside of the rotor shell, in the exhaust flow path setting project, the exhaust port is set as at least a part of the exhaust flow path. A method for modifying a steam turbine as described in any one of claims 1 to 3, wherein: the steam turbine has a steam valve capable of separating the downstream steam flow path; in the flow path separation process, the steam valve is closed to separate the downstream steam flow path. A method for modifying a steam turbine as described in any one of claims 1 to 3, wherein, In the aforementioned flow path separation process, a partition plate is used to separate the aforementioned steam flow path, The aforementioned partition plate has: an inner end portion, which is an end portion on the inner side of the radial direction of the aforementioned axis; and an outer end portion, which is an end portion on the outer side of the radial direction of the aforementioned radial direction, In the aforementioned flow path separation process, the aforementioned outer end portion of the aforementioned partition plate is connected to the aforementioned rotor shell. A steam turbine modification method as described in claim 5, wherein, in the flow path partitioning process, the outer end of the partition plate is connected to a stationary wing row mounting portion, the stationary wing row mounting portion being the stationary wing row closest to the upstream side of the axis among the stationary wing rows removed by the wing removal process and having been installed in the rotor casing. A method for modifying a steam turbine as described in claim 5, wherein: the steam turbine is provided with a stationary part which is arranged at a position further downstream of the axis than the last stage active wing row and has a portion along the outer peripheral surface of the rotor shaft, and in the flow path partitioning process, the inner end of the partition plate is brought into contact with the stationary part. A method for modifying a steam turbine as described in claim 7, wherein, in the flow path partitioning process, the inner end of the partition plate is movable in a direction including a directional component of expansion of the partition plate so that the inner end of the partition plate contacts the stationary part. A method for modifying a steam turbine as described in claim 7, wherein the aforementioned stationary part is a shaft sealing device facing the outer peripheral surface of the aforementioned rotor shaft and capable of suppressing the outflow of steam to the downstream side of the aforementioned axis. A method for modifying a steam turbine as described in any one of claims 1 to 3, wherein the steam turbine is provided with an exhaust casing that can guide the steam flowing from the steam flow path to the condenser, and an exhaust port plugging process is performed to plug the exhaust port in the exhaust casing for discharging steam from the condenser. A method for modifying a steam turbine as described in any one of claims 1 to 3, wherein a spray nozzle installation project is performed to install a spray nozzle, and cooling water can be sprayed from a space on the side away from the last stage active wing row at a position in the steam flow path or the downstream side steam flow path where the steam flow path or the downstream side steam flow path is separated. A steam turbine comprises: a rotor rotatable about an axis, a rotor shell covering the outer periphery of the rotor, one or more rows of stationary wing rows arranged on the inner periphery of the rotor shell and arranged in parallel in the axial direction extending from the axis, a partition member for dividing a steam flow path or a downstream steam flow path connected to the steam flow path, an exhaust flow path forming portion for forming an exhaust flow path capable of guiding steam to the outside of the rotor shell, the rotor having: a rotor shaft centered about the axis and extending in the axial direction, and one or more rows of movable wing rows arranged on the rotor shaft, The above-mentioned active wing rows of more than one row are respectively arranged at: the downstream side of the axis in the above-mentioned axial direction of any one of the above-mentioned static wing rows of more than one row, the above-mentioned steam flow path is an annular flow path formed between the inner peripheral side of the above-mentioned rotor shell and the outer peripheral side of the above-mentioned rotor shaft, the above-mentioned partition member is located closer to the downstream side of the above-mentioned axis than the active wing row closest to the downstream side of the above-mentioned axis among the above-mentioned active wing rows, that is, the final active wing row, to separate the above-mentioned steam flow path or the above-mentioned downstream side steam flow path, The exhaust flow path can guide the steam in the space on the side of the aforementioned final section active wing row in the aforementioned steam flow path or the aforementioned downstream side steam flow path that is closer to the side where the aforementioned steam flow path or the aforementioned downstream side steam flow path is separated to the outside of the aforementioned rotor casing. A steam turbine as described in claim 12, wherein: the rotor casing has a stationary wing row mounting portion on the downstream side of the axis than the last movable wing row, which can be mounted with a stationary wing row but is not mounted with a stationary wing row, the rotor shaft has a movable wing row mounting portion on the downstream side of the axis than the last movable wing row, which can be mounted with a movable wing row but is not mounted with a movable wing row. A steam turbine as described in claim 12, wherein, a steam valve capable of separating the aforementioned downstream steam flow path is provided as the aforementioned separation member, and the aforementioned steam valve is in a closed state when separating the aforementioned downstream steam flow path. A steam turbine as described in claim 12, wherein, a partition plate for partitioning the steam flow path is provided as the partition member, the partition plate has: an inner end portion, which is an end portion radially inward of the axis in the radial direction; and an outer end portion, which is an end portion radially outward of the radial direction, the outer end portion of the partition plate is connected to the rotor casing. A steam turbine as described in claim 13, wherein, a partition plate for partitioning the steam flow path is provided as the partition member, the partition plate has: an inner end portion, which is an end portion radially inward of the axis in the radial direction; and an outer end portion, which is an end portion radially outward of the radial direction, the outer end portion of the partition plate is connected to the stationary wing row mounting portion of the rotor shell. A steam turbine as described in claim 15, wherein: the steam turbine has a stationary part which is arranged at a position further downstream of the axis than the last stage active wing row and has a portion along the outer circumference of the rotor shaft, and the inner end of the partition plate contacts the stationary part. A steam turbine as described in claim 17, wherein the inner end of the partition plate is in contact with the stationary part so that the inner end of the partition plate can move in a direction including a directional component of expansion of the partition plate. A steam turbine as described in claim 17 or 18, wherein the aforementioned stationary part is a shaft sealing device facing the outer peripheral surface of the aforementioned rotor shaft and inhibiting the steam from flowing out to the downstream side of the aforementioned axis. A steam turbine as described in any one of claims 12 to 18, wherein the steam turbine comprises: an exhaust casing that can discharge steam flowing from the steam flow path to the condenser; and a plug that can block the exhaust port of the condenser in the exhaust casing for discharging steam. A steam turbine as described in any one of claims 12 to 18, wherein, a spray nozzle is provided, which can spray cooling water into the space on the side farther from the aforementioned final stage active wing row than the aforementioned partition member in the aforementioned steam flow path or the aforementioned downstream side steam flow path.

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