Steam turbine and modification method thereof

Abstract

In this method for reforming a steam turbine, a blade removal step and a flow path separation step are executed. In the blade removal step, a plurality of rotor blade rows, which are adjacent to each other in the axial direction and include the rotor blade row closest to the downstream side of the axis, among the plurality of rotor blade rows are removed, and a stator blade row, which is adjacent to the upstream side of the axis of each of the plurality of rotor blade rows to be removed, among the plurality of stator blade rows is removed. In the flow path partitioning step, an annular steam flow path formed between the inner peripheral side of the rotor housing and the outer peripheral side of the rotor shaft is partitioned on the downstream side of the axial line than a final stage blade row, which is the blade row closest to the downstream side of the axial line, among the one or more blade rows left after the blade removal step.

Description

Technical Field

[0001] The invention relates to a steam turbine and a modification method thereof.

[0002] This application claims priority based on Japanese Patent Application No. 2022-161529 filed in Japan on October 6, 2022, the contents of which are cited herein. Background Art

[0003] Steam turbine equipment generally includes a boiler, a steam turbine driven by steam from the boiler, a generator that generates electricity by driving the steam turbine, and a condenser that converts steam exhausted from the steam turbine into water.

[0004] For example, the following patent document 1 discloses a method for modifying a steam turbine device for effectively utilizing the heat of steam generated in a boiler. The steam turbine device before modification in the patent document 1 includes: 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 that generates electricity by driving the high-pressure steam turbine and the low-pressure steam turbine; and a condenser that recovers steam exhausted from the low-pressure steam turbine to water. In the technology described in the patent document 1, the steam turbine device is modified so that the steam exhausted from the high-pressure steam turbine is not guided to the low-pressure steam turbine, but is guided to other steam utilization equipment as process steam. In this technology, although the amount of power generated by the generator is reduced because the steam is not guided to the low-pressure steam turbine, the heat loss generated in the process of recovering the steam to water through the condenser disappears, so the heat of the steam from the boiler can be effectively utilized.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-002696 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the technology described in the above-mentioned Patent Document 1, although the heat of the steam from the boiler can be effectively utilized, there are restrictions on the pressure and temperature of the steam delivered to the steam utilization equipment. Therefore, in the technology described in the above-mentioned Patent Document 1, steam with the pressure and temperature required by the steam utilization equipment may not be supplied.

[0010] Therefore, an object of the present disclosure is to provide a steam turbine modification method capable of supplying steam of a pressure and temperature corresponding to requirements of a steam utilization side to a steam utilization device, and a steam turbine obtained by executing the modification method.

[0011] Solutions for solving problems

[0012] A steam turbine modification method according to one aspect of the invention for achieving the above-mentioned object targets the following steam turbine.

[0013] The steam turbine comprises: a rotor rotatable around an axis; a rotor housing covering the outer circumference of the rotor; and a plurality of stationary blade rows arranged on the inner circumference of the rotor housing and arranged in the axial direction in which the axis extends. The rotor comprises: a rotor shaft extending in the axial direction around the axis; and a plurality of moving blade rows arranged on the rotor shaft. The plurality of moving blade rows are respectively arranged on the axial downstream side of any one of the plurality of stationary blade rows in the axial direction.

[0014] In the steam turbine modification method, a blade removal process is performed to remove a plurality of moving blade rows including a moving blade row closest to the downstream side of the axis and adjacent to each other in the axial direction or a moving blade row closest to the downstream side of the axis, and to remove a stationary blade row adjacent to the upstream side of the axis in the axial direction of each of the one or more moving blade rows to be removed, leaving at least the moving blade row closest to the upstream side of the axis, and leaving at least the stationary blade row closest to the upstream side of the axis among the multiple moving blade rows; and a flow path separation process to separate an annular steam flow path formed between the inner circumference of the rotor casing and the outer circumference of the rotor shaft at a position closer to the downstream side of the axis than the moving blade row closest to the downstream side of the axis, i.e., the final-stage moving blade row, among the one or more moving blade rows remaining after the blade removal process.

[0015] In this scheme, the steam from the steam turbine can be delivered to the steam utilization equipment in the upstream space closer to the final stage moving blade row side than the position where the steam flow path is divided, instead of being delivered to the condenser. Therefore, in this scheme, the heat loss generated in the process of returning the steam to water through the condenser disappears, and the heat of the steam from the boiler can be effectively utilized.

[0016] Furthermore, in the present embodiment, by appropriately selecting the blade row stage to be removed, steam having a pressure and a temperature corresponding to the requirements of the steam utilization side can be delivered to the steam utilization equipment.

[0017] A steam turbine of one embodiment of the invention for achieving the above object comprises: a rotor rotatable about an axis; a rotor housing covering the outer circumference of the rotor; a plurality of stationary blade rows or a single stationary blade row provided on the inner circumference of the rotor housing and arranged in the axial direction in which the axis extends; a partition plate partitioning a steam flow path; and an exhaust flow path forming portion forming an exhaust flow path capable of guiding steam to the outside of the rotor housing. The rotor comprises: a rotor shaft extending in the axial direction about the axis; and a plurality of moving blade rows or a single moving blade row provided on the rotor shaft. One or more moving blade rows are respectively arranged on the axial downstream side of any one of the one or more stationary blade rows in the axial direction. The steam flow path is an annular flow path formed between the inner circumference of the rotor housing and the outer circumference of the rotor shaft. The partition plate partitions the steam flow path at a position closer to the axial downstream side than the moving blade row closest to the axial downstream side, i.e., the final stage moving blade row, among the one or more moving blade rows. The exhaust flow path can guide steam in a space in the steam flow path that is closer to the final-stage rotor blade row than a position that divides the steam flow path to the outside of the rotor casing.

[0018] Effects of the Invention

[0019] According to one aspect of the present disclosure, steam having a pressure and a temperature corresponding to a requirement of a steam utilization side can be delivered to a steam utilization device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic cross-sectional view of the steam turbine before modification according to the first embodiment of the present disclosure.

[0021] Figure 2 It is a flowchart showing the process of the steam turbine modification method according to the first embodiment and the second embodiment of the present disclosure.

[0022] Figure 3 It is a schematic cross-sectional view of a steam turbine after modification according to the first embodiment of the present disclosure.

[0023] Figure 4 This is a cross-sectional view of a main part of a steam turbine after modification according to the first embodiment of the present disclosure.

[0024] Figure 5 It is a schematic cross-sectional view of a steam turbine after modification according to the second embodiment of the present disclosure.

[0025] Figure 6 It is a cross-sectional view of a main part of a steam turbine after modification according to a second embodiment of the present disclosure.

[0026] Figure 7 It is a schematic cross-sectional view of a steam turbine after modification according to a third embodiment of the present disclosure.

[0027] Figure 8 It is a cross-sectional view of a main part of a steam turbine after modification according to a third embodiment of the present disclosure.

[0028] Fig. 9 It is a schematic cross-sectional view of a steam turbine after modification according to a modification example of the first embodiment of the present disclosure.

[0029] Fig.10 It is a schematic cross-sectional view of a steam turbine after modification according to a modification example of the third embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments and modifications of a steam turbine modification method of the present disclosure and a steam turbine obtained by executing the modification method will be described in detail with reference to the drawings.

[0031] "First Implementation Method"

[0032] Reference Figure 1 to Figure 4 , a steam turbine modification method according to a first embodiment and a steam turbine obtained by executing the modification method are described.

[0033] First, refer to Figure 1 The steam turbine 10 before the transformation is described below. The steam turbine 10 before the transformation includes a high-pressure steam turbine section 20 and a low-pressure steam turbine section 50 .

[0034] The high-pressure steam turbine section 20 includes: a high-pressure rotor 21, which can rotate around the axis Ar; a high-pressure rotor casing 30, which 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 sealing device 42; and an intermediate shaft sealing device 43.

[0035] Here, the direction in which the axis Ar extends is defined as the axis direction Da, one side in the axis direction Da is defined as the axis upstream side Dau, and the other side in the axis direction Da is defined as the axis downstream side Dad. In addition, the direction perpendicular to the axis Ar is defined as the radial direction Dr, the side close to the axis Ar in the radial direction Dr is defined as the radial inner side Dri, and the side away from the axis Ar in the radial direction Dr is defined as the radial outer side Dro. Moreover, the circumferential direction relative to the axis Ar is defined as only the circumferential direction Dc.

[0036] The high-pressure rotor 21 includes: a high-pressure rotor shaft 22 extending in the axial direction Da with the axis Ar as the center; and a plurality of moving blade rows 25 provided on the high-pressure rotor shaft 22. The high-pressure steam turbine unit 20 of the present embodiment includes four moving blade rows 25. The plurality of moving blade rows 25 are arranged in the axial direction Da at intervals from each other. Each of the plurality of moving blade rows 25 includes a plurality of moving blades 26 arranged in the circumferential direction Dc. The moving blade 26 includes: a blade body 27 having a blade shape in cross section and extending in a radial direction Dr perpendicular to the cross section; and a blade root 28 provided on the radial inner side Dri of the blade body 27. A moving blade row mounting portion 23 is formed on the high-pressure rotor shaft 22 to which the blade roots 28 of the plurality of moving blades 26 constituting the moving blade row 25 are mounted. The moving blade row mounting portion 23 is an annular groove recessed from the outer circumference of the high-pressure rotor shaft 22 to the radial inner side Dri.

[0037] The plurality of stationary blade rows 36 are respectively arranged on the axial upstream side Dau of any one of the plurality of moving blade rows 25. Therefore, the high-pressure steam turbine section 20 of the present embodiment has four stationary blade rows 36. That is, the high-pressure steam turbine section 20 of the present embodiment has four blade row stages. It should be noted that one blade row stage is composed of one stationary blade row 36 and one moving blade row 25. The plurality of stationary blade rows 36 each have a plurality of blade bodies 37 arranged in the circumferential direction Dc, an annular outer ring 38 centered on the axis Ar, and an inner ring 39. The cross section of the blade body 37 is blade-shaped and extends in a radial direction Dr perpendicular to the cross section. The outer ring 38 connects the ends of the radially outer sides Dro of the plurality of blade bodies 37 arranged in the circumferential direction Dc to each other. The inner ring 39 connects the ends of the radially inner sides Dri of the plurality of blade bodies 37 arranged in the circumferential direction Dc to each other. A stationary blade row assembly portion 32 for assembling each of the plurality of stationary blade rows 36 is formed in the high-pressure rotor housing 30. The stationary blade row mounting portion 32 is an annular groove that is recessed from the inner peripheral surface of the high-pressure rotor housing 30 toward the radially outer side Dro.

[0038] In the high-pressure rotor casing 30, a high-pressure steam pipe 40 is connected to a position closer to the upstream side Dau of the stationary blade row 36 that is closest to the upstream side Dau of the axis among the plurality of stationary blade rows 36. A high-pressure steam valve 41 is provided in the high-pressure steam pipe 40. In the high-pressure rotor casing 30, a high-pressure steam exhaust port 33 is formed closer to the downstream side Dad of the axis than the moving blade row 25 that is closest to the downstream side Dad of the axis among the plurality of moving blade rows 25. An annular space between the inner peripheral side of the high-pressure rotor casing 30 and the outer peripheral side of the high-pressure rotor shaft 22 that is closer to the downstream side Dad of the axis than the high-pressure steam pipe 40 and closer to the upstream side Dau of the axis than 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.

[0039] In the high-pressure rotor housing 30, a high-pressure shaft sealing device 42 is arranged on the upstream side Dau closer to the axis than the high-pressure steam pipe 40. The high-pressure shaft sealing device 42 is a device that suppresses the high-pressure steam in the high-pressure rotor housing 30 from flowing out from between the high-pressure rotor housing 30 and the high-pressure rotor shaft 22. The high-pressure shaft sealing device 42 includes: a seal 42s, which is opposite to the outer peripheral surface of the high-pressure rotor shaft 22; and a seal support platform 42b, which supports 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 housing 30.

[0040] In the high-pressure rotor housing 30, an intermediate shaft sealing device 43 is arranged on the downstream side Dad closer to the axis than the high-pressure steam exhaust port 33. The intermediate shaft sealing device 43 is a device that suppresses the high-pressure steam in the high-pressure rotor housing 30 from flowing out from between the high-pressure rotor housing 30 and the high-pressure rotor shaft 22. The intermediate shaft sealing device 43 includes: a seal 43s, which is opposite to the outer peripheral surface of the high-pressure rotor shaft 22; and a seal support platform 43b, which supports 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 housing 30.

[0041] 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 that can rotate around the axis Ar; a low-pressure rotor casing 60 that covers the outer periphery of the low-pressure rotor 51; a plurality of stationary blade rows 66; a low-pressure steam pipe 70; a low-pressure steam valve 71; a low-pressure shaft sealing device 72; and an exhaust casing 75.

[0042] The low-pressure rotor 51 has: a low-pressure rotor shaft 52 extending in the axial direction Da with the axis Ar as the center; and a plurality of moving blade rows 55 provided on the low-pressure rotor shaft 52. The low-pressure steam turbine section 50 of the present embodiment has seven moving blade rows 55. The plurality of moving blade rows 55 are arranged in the axial direction Da at intervals from each other. The plurality of moving blade rows 55 each have a plurality of moving blades 56 arranged in the circumferential direction Dc. The moving blade 56 has: a blade body 57 having a blade-shaped cross section extending in a radial direction Dr perpendicular to the cross section; and a blade root 58 provided on the radial inner side Dri of the blade body 57. A moving blade row mounting portion 53 is formed on the low-pressure rotor shaft 52 to which the blade roots 58 of the plurality of moving blades 56 constituting the moving blade row 55 are mounted. The moving blade row mounting portion 53 is an annular groove recessed from the outer circumference of the low-pressure rotor shaft 52 to the radial inner side Dri.

[0043] The plurality of stationary blade rows 66 are respectively arranged on the axial upstream side Dau of any one of the plurality of moving blade rows 55. Therefore, the low-pressure steam turbine section 50 of the present embodiment has seven stationary blade rows 66. That is, the low-pressure steam turbine section 50 of the present embodiment has seven blade row stages. It should be noted that one blade row stage is composed of one stationary blade row 66 and one moving blade row 55. The plurality of stationary blade rows 66 each have a plurality of blade bodies 67 arranged in the circumferential direction Dc, an annular outer ring 68 centered on the axis Ar, and an inner ring 69. The cross section of the blade body 67 is blade-shaped and extends in a radial direction Dr perpendicular to the cross section. The outer ring 68 connects the ends of the radially outer sides Dro of the plurality of blade bodies 67 arranged in the circumferential direction Dc to each other. The inner ring 69 connects the ends of the radially inner sides Dri of the plurality of blade bodies 67 arranged in the circumferential direction Dc to each other.

[0044] The low-pressure rotor casing 60 includes a casing body 61 and a diffuser 64 .

[0045] The casing body 61 covers the outer periphery of the low-pressure rotor 51 and has a portion in the axial direction Da where a plurality of stationary blade rows 66 and a plurality of moving blade rows 55 exist. In the casing 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 blade row 66 closest to the axial upstream side Dau among the plurality of stationary blade 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 casing 30. Therefore, the low-pressure steam pipe 70 forms a downstream steam flow path 70p that communicates with 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 becoming a closed state. In the casing body 61, an exhaust port 63 that passes from the inner peripheral side to the outer peripheral side of the casing body 61 is formed at a substantially middle position in the axial direction Da. Specifically, the air extraction port 63 is formed between the second and third blade row stages in the axial direction Da among the seven blade row stages. One end of the first steam supply line 96a is connected to the air extraction port 63 of the casing body 61. The other end of the first steam supply line 96a is connected to the first steam utilization device 95a.

[0046] The diffuser 64 is arranged on the axial downstream side Dad of the casing body 61. The diffuser 64 is annular relative to the axis Ar, forming a space that gradually moves toward the radial outer side Dro as it approaches the axial downstream side Dad. Steam from the moving blade row 55 closest to the axial downstream side Dad among the multiple moving blade rows 55 flows into the annular space. The diffuser 64 has: an outer diffuser (or steam guide, flow guide) 64o, which defines the edge of the radial outer side Dro of the annular space; and an inner diffuser (or bearing cone) 64i, which defines the edge of the radial inner side Dri of the space. The cross-section of the outer diffuser 64o perpendicular to the axis Ar is annular, and gradually expands toward the radial outer side Dro as it approaches the axial downstream side Dad. The end of the outer diffuser 64o on the axial upstream side Dau is connected to the end of the low-pressure rotor casing 60 on the axial downstream side Dad. The inner diffuser 64i has an annular cross section perpendicular to the axis Ar, and gradually expands toward the radially outer side Dro as it approaches the axial downstream side Dad. The end of the inner diffuser 64i on the axial downstream side Dad is connected to the exhaust casing 75.

[0047] The exhaust housing 75 forms an exhaust space 76 into which the steam passing through the diffuser 64 flows. The exhaust housing 75 has an exhaust port 77 for exhausting the steam in the exhaust space 76 to the condenser 99 .

[0048] The annular space between the inner circumference of the casing body 61 and the outer circumference of the low-pressure rotor shaft 52, which is closer to the axial downstream side Dad than the low-pressure steam pipe 70 and closer to the axial upstream side Dau than the diffuser 64, and the annular space within the diffuser 64 form an annular low-pressure steam flow path 65 for the low-pressure steam from the low-pressure steam pipe 70 to flow.

[0049] A low-pressure shaft sealing device 72 is arranged on the inner peripheral side of the inner diffuser 64i. The low-pressure shaft sealing device 72 is a device that suppresses the low-pressure steam in the low-pressure rotor housing 60 from flowing out from between the low-pressure rotor housing 60 and the low-pressure rotor shaft 52. The high-pressure shaft sealing device 72 includes: a seal 72s, which is opposite to the outer peripheral surface of the low-pressure rotor shaft 52; and a seal support platform 72b, which supports 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 diffuser 64i of the low-pressure rotor housing 60.

[0050] 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 casing 30, the low-pressure rotor casing 60 and the exhaust casing 75 are connected to each other to form the steam turbine casing 15. The end of the steam turbine rotor 11 on the upstream side Dau of the axis protrudes from the inside of the steam turbine casing 15 to the upstream side Dau of the axis. In addition, the end of the steam turbine rotor 11 on the downstream side Dad of the axis protrudes from the inside of the steam turbine casing 15 to the downstream side Dad of the axis. The steam turbine 10 of this embodiment also has a first bearing 16 and a second bearing 17 that can support the steam turbine rotor 11 so that it can rotate. The first bearing 16 supports the portion of the steam turbine rotor 11 that protrudes from the inside of the steam turbine casing 15 to the upstream side Dau of the axis so that it can rotate. The second bearing 17 supports the portion of the steam turbine rotor 11 that protrudes from the inside of the steam turbine casing 15 to the downstream side Dad of the axis so that it can rotate.

[0051] Next, follow Figure 2 The flowchart shown will explain the modification method of the steam turbine 10 described above.

[0052] Assume that a user requests that steam of the first pressure and the first temperature be supplied from the steam flowing in the steam turbine 10 before the modification described above. Assume that the steam passing through the fourth blade row stage in the low-pressure steam turbine section 50 is at the first pressure and the first temperature. In this case, Figure 3 and Figure 4 As shown in FIG. 1 , the fourth blade row stage and all blade row stages closer to the axial upstream side Dau than the fourth blade row stage in the low-pressure steam turbine section 50 are left in advance, while all blade row stages closer to the axial downstream side Dad than the fourth blade row stage are removed (blade removal process S1). Specifically, the stationary blade row 66 and the moving blade row 55 constituting the fifth blade row stage, the stationary blade row 66 and the moving blade row 55 constituting the sixth blade row stage, and the stationary blade row 66 and the moving blade row 55 constituting the seventh blade row stage closest to the axial downstream side Dad among the plurality of blade row stages are removed. As a result, the moving blade row 55 constituting the fourth blade row stage becomes the final stage moving blade row 55z in the steam turbine 10a after the reconstruction.

[0053] Next, the partition plate 80 as a partition member is used to divide the annular low-pressure steam flow path 65 at a position closer to the downstream side Dad of the axis than the final stage moving blade row 55z (flow path partitioning step 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 as it approaches the downstream side Dad of the axis. The outer end 82 is provided at the end of the radially outer side Dro of the partition plate body 81 and the end of the axis upstream side Dau. The outer peripheral end is annular with the axis Ar as the center. In addition, the inner end 83 is provided at the end of the radially inner side Dri of the partition plate body 81 and the end of the axis downstream side Dad. The inner end 83 is annular with the axis Ar as the center. The inner end 83 has a partition plate seal 84 that seals between the partition plate 80 and the low-pressure shaft sealing device 72. The annular outer end 82 is embedded in the stator row assembly part 62 which is an annular groove and is assembled to the low-pressure rotor housing 60. The stator row assembly part 62 is a stator row assembly part to which the outer ring 68 of the stator row 66 of the fifth blade row level removed in the blade removal process S1 among the multiple stator row assembly parts 62 constituting the low-pressure rotor housing 60 is assembled. The partition plate seal 84 of the annular inner end 83 is brought into contact with the seal support platform 72b of the annular low-pressure shaft sealing device 72. The seal support platform 72b has an outer surface extending in the axial direction Da. The partition plate seal 84 is in contact with the outer surface of the seal support platform 72b in a manner that can move relative to the seal support platform 72b in the axial direction Da.

[0054] In the present embodiment, the outer end 82 of the partition plate 80 is mounted on the stator blade row mounting portion 62 formed in 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. Moreover, in the present embodiment, the outer end 82 of the partition plate 80 is embedded in the stator blade row mounting portion 62 which is a groove recessed toward the radially outer side. Therefore, in the present embodiment, steam leakage from between the low-pressure rotor casing 60 and the outer end 82 of the partition plate 80 can be suppressed.

[0055] 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 suppress leakage of steam from between the inner end portion 83 and the contacting object.

[0056] The partition plate 80 expands in a direction including the radial direction Dr and the axial direction Da. As described above, the inner end 83 of the partition plate 80 can move in the axial direction Da relative to the low-pressure shaft sealing device 72. Therefore, the inner end 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 the present embodiment, even when the partition plate 80 is extended by heat, the inner end 83 of the partition plate 80 moves, allowing the extension of the partition plate 80.

[0057] In the present embodiment, the inner end portion 83 of the partition plate 80 is brought into contact with the low-pressure shaft seal device 72 as a stationary part. However, the inner end portion 83 of the partition plate 80 may be brought into contact with the inner diffuser 64i. In this case, the stationary parts that the inner end portion 83 contacts include the low-pressure shaft seal device 72 and the inner diffuser 64i.

[0058] Next, an exhaust flow path is set in the low-pressure steam flow path 65, and the exhaust flow path can guide the steam in the upstream space 65u closer to the final stage blade row 55z side than the position where the low-pressure steam flow path 65 is divided by the partition plate 80 to the outside of the low-pressure rotor casing 60 (exhaust flow path setting step S3). In the exhaust flow path setting step S3, an exhaust pipe (exhaust flow path forming portion) 85 forming the exhaust flow path is provided. 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 of the steam supply client. Therefore, the exhaust pipe 85 forms a second steam supply line for conveying the steam in the upstream space 65u to the second steam utilization device 95b.

[0059] 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 flows into the downstream space 65d which is farther from the final-stage rotor blade row 55z than the position where the low-pressure steam flow path 65 is partitioned by the partition plate 80, and there is a possibility that the steam becomes drainage in the downstream space 65d. Therefore, it is preferable to provide a drainage discharge pipe 87 for discharging drainage from the exhaust space 76 communicating with the downstream space 65d to the outside of the low-pressure steam turbine unit 50 in the blocking plate 86.

[0060] Next, a thermometer 93 capable of sensing the temperature of the downstream space 65d and a spray nozzle 90 capable of spraying cooling water into the downstream space 65d are provided (spray nozzle installation step S5). A cooling water line 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 line 91 is provided in the cooling water line 91. When the temperature sensed by the thermometer 93 is higher than a predetermined temperature, the regulating valve 92 is opened. Here, the predetermined temperature refers to, for example, the design temperature of the exhaust casing 75. Therefore, when the temperature of the downstream space 65d is higher than the design temperature of the exhaust casing 75, cooling water is sprayed from the spray nozzle 90 into the downstream space 65d.

[0061] The temperature of the steam in the upstream space 65u in the low-pressure steam flow path 65 is higher than the temperature of the steam passing through the moving blade row 55 closest to the downstream side Dad in the steam turbine 10 before the modification. The pressure of the steam in the upstream space 65u in the low-pressure steam flow path 65 is higher than the pressure of the steam passing through the moving blade row 55 closest to the downstream side Dad in the steam turbine 10 before the modification. In addition, the design temperature and design pressure of the exhaust casing 75 are set based on the temperature and pressure of the steam passing through the moving blade row 55 closest to the downstream side Dad in the steam turbine 10 before the modification. Therefore, when a 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 and the low-pressure shaft sealing device 72 are damaged.

[0062] Therefore, in this embodiment, a spray nozzle 90 is provided that can spray cooling water into the downstream side space 65d, so that even if a part 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 the specified temperature, and the pressure in the downstream side space 65d and the exhaust space 76 will not rise above the specified pressure.

[0063] The above is the end of the modification of the steam turbine 10 of the present embodiment. It should be noted that the exhaust flow path setting step S3, the exhaust port blocking step S4, and the spray nozzle setting step S5 in the above steps can be performed at any stage. For example, the spray nozzle setting step S5 can also be performed before the blade removal step S1.

[0064] In the steam turbine 10a obtained by the modification described above, all blade row stages closer to the axis downstream side Dad than the fourth blade row stage in the low-pressure steam turbine section 50 before the modification are missing. However, in the steam turbine 10a obtained by the modification, the stationary blade row mounting portion 62 to which the stationary blade row 66 constituting the removed blade row stage was mounted and the moving blade row mounting portion 53 to which the moving blade row 55 constituting the removed blade row stage was mounted remain. 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.

[0065] As described above, in this embodiment, the steam from the steam turbine 10a is not delivered to the condenser 99 but is delivered to the second steam utilization device 95b. Therefore, the heat loss generated in the process of restoring the steam to water through the condenser 99 disappears, and the heat of the steam from the boiler can be effectively utilized.

[0066] Furthermore, in the present embodiment, by appropriately selecting the blade row stage to be removed, steam having a pressure and a temperature corresponding to the requirements of the steam utilization side can be supplied to the steam utilization equipment.

[0067] Furthermore, in the present embodiment, steam having a pressure and a temperature corresponding to the requirements of the steam utilization side can be supplied to the steam utilization equipment by modification within one casing.

[0068] "Second Implementation Method"

[0069] Reference Figure 2 , Figure 5 as well as Figure 6 , a steam turbine modification method according to a second embodiment and a steam turbine obtained by executing the modification method are described.

[0070] The steam turbine before the transformation of this embodiment is used Figure 1 The steam turbine 10 has been described.

[0071] according to Figure 2 The flowchart shown in FIG. 1 will now explain a method for modifying the steam turbine 10 according to the present embodiment.

[0072] Assume that a user requests to supply steam of the second pressure and the second temperature among the steam flowing in the steam turbine 10 before the modification. Assume that the steam passing through the second blade row stage in the low-pressure steam turbine section 50 is at the second pressure and the second temperature. In this case, Figure 5 and Figure 6As shown in FIG. 1 , the second blade row stage and all blade row stages closer to the axial upstream side Dau than the second blade row stage in the low-pressure steam turbine section 50 are left in advance, while all blade row stages closer to the axial downstream side Dad than the second blade row stage are removed (blade removal process S1). Specifically, the stationary blade row 66 and the moving blade row 55 constituting the third blade row stage, the stationary blade row 66 and the moving blade row 55 constituting the fourth blade row stage, the stationary blade row 66 and the moving blade row 55 constituting the fifth blade row stage, the stationary blade row 66 and the moving blade row 55 constituting the sixth blade row stage, and the stationary blade row 66 and the moving blade row 55 constituting the seventh blade row stage closest to the axial downstream side Dad among the plurality of blade row stages are removed. As a result, the moving blade row 55 constituting the second blade row stage becomes the final stage moving blade row 55z in the steam turbine 10b after the reconstruction.

[0073] Next, the partition plate 80a as a partition member is used to partition the annular low-pressure steam flow path 65 at a position closer to the axis downstream side Dad than the final stage moving blade row 55z (flow path partitioning step 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 as it approaches the axis downstream side Dad. The outer end 82a is provided at the end of the radially outer side Dro of the partition plate body 81a and the end of the axis upstream side Dau. The outer end 82a is annular with the axis Ar as the center. In addition, the inner end 83a is provided at the end of the radially inner side Dri of the partition plate body 81a and the end of the axis downstream side Dad. The inner end 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 that seals between the partition plate 80a and the low-pressure rotor shaft 52. The annular outer end portion 82a is fitted into the stationary blade row assembly portion 62 as an annular groove and assembled to the low-pressure rotor housing 60. The stationary blade row assembly portion 62 is a stationary blade row assembly portion 62 to which the outer ring 68 of the stationary blade row 66 of the third blade row stage removed in the blade removal step S1 among the plurality of stationary blade row assembly portions 62 constituting the low-pressure rotor housing 60 is assembled. The partition plate seal 84a of the annular inner end portion 83a contacts the outer peripheral surface of the low-pressure rotor shaft 52 in a manner that can move in the axial direction Da relative to the low-pressure rotor shaft 52.

[0074] The partition plate 80a of the present embodiment also expands in a direction including the radial direction Dr and the axial direction Da. As described above, the inner end 83a of the partition plate 80a can move in the axial direction Da relative to the low-pressure rotor shaft 52. Therefore, the inner end 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 when the partition plate 80a is extended by heat, the inner end 83a of the partition plate 80a moves, allowing the extension of the partition plate 80a.

[0075] Next, an exhaust flow path is set in the low-pressure steam flow path 65, which can guide the steam in the upstream side space 65u closer to the final stage moving blade row 55z side than the position where the low-pressure steam flow path 65 is divided by the partition plate 80a to the outside of the low-pressure rotor casing 60 (exhaust flow path setting step S3a). As described above, in the low-pressure rotor casing 60 of the steam turbine 10 before the modification, the air extraction port 63 is provided at a position between the second blade row stage and the third blade row stage in the axial direction Da. The air extraction port 63 is a hole that can guide the steam in the upstream side space 65u closer to the final stage moving blade row 55z side than the position where the low-pressure steam flow path 65 is divided by the partition plate 80a to the outside of the low-pressure rotor casing 60. As described above, the first steam supply line 96a for supplying steam to the existing first steam utilization device 95a is connected to the air extraction port 63. Therefore, in the exhaust flow path setting step S3a, the air extraction port 63 and a part of the first steam supply line 96a are set as a part of the exhaust flow path. Furthermore, in the exhaust flow path setting step S3a, the existing first steam supply line 96a is connected to the new third steam utilization device 95c through the third steam supply line 96c. Therefore, in the present embodiment, the steam in the upstream space 65u can be transported to the first steam utilization device 95a via the first steam supply line 96a, and the steam in the upstream space 65u can be transported to the third steam utilization device 95c via 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.

[0076] Next, similarly to the first embodiment, the exhaust port 77 of the exhaust case 75 is blocked by the blocking plate 86 (exhaust port blocking step S4 ).

[0077] Next, similarly to the first embodiment, a thermometer 93 capable of sensing the temperature of the downstream space 65d and a spray nozzle 90 capable of spraying cooling water into the downstream space 65d are provided (spray nozzle installation step S5). A cooling water line 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 line 91 is provided in the cooling water line 91. When the temperature sensed by the thermometer 93 is equal to or higher than a predetermined temperature, the regulating valve 92 is opened.

[0078] As described above, the modification of the steam turbine 10 according to the present embodiment is completed.

[0079] In the steam turbine 10b obtained by the modification described above, all blade row stages closer to the axis downstream side Dad than the second blade row stage in the low-pressure steam turbine section 50 before the modification are missing. However, in the steam turbine 10b obtained by the modification, the stationary blade row mounting portion 62 to which the stationary blade row 66 constituting the removed blade row stage was mounted and the moving blade row mounting portion 53 to which the moving blade row 55 constituting the removed blade row stage was mounted remain. 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.

[0080] As described above, in this embodiment, as in the first embodiment, the steam from the steam turbine 10b is not transported to the condenser 99, but is transported to the third steam utilization device 95c. Therefore, the heat loss generated in the process of restoring the steam to water through the condenser 99 disappears, and the heat of the steam from the boiler can be effectively utilized.

[0081] Furthermore, in the present embodiment, as in the first embodiment, by appropriately selecting the blade row stage to be removed, steam of a pressure and temperature corresponding to the requirements of the steam utilization side can be fed to the steam utilization equipment.

[0082] In this embodiment, steam is transported to the new third steam utilization device 95c in addition to the existing first steam utilization device 95a. However, if there is a demand to increase the steam flow rate from the existing first steam utilization device 95a, almost all of the steam in the upstream space 65u described above may be transported to the first steam utilization device 95a via the first steam supply line 96a.

[0083] In this case, in the exhaust flow path setting step S3a, it is not necessary to provide the third steam supply line 96c described above, and the actual work in the exhaust flow path setting step S3a is eliminated. Therefore, in this case, the exhaust flow path setting step S3a is unnecessary.

[0084] "Third Implementation Method"

[0085] Reference Figure 7 and Figure 8 , a steam turbine modification method according to a third embodiment and a steam turbine obtained by executing the modification method are described.

[0086] The steam turbine before the transformation of this embodiment is used Figure 1 The steam turbine 10 has been described.

[0087] Assume that a user requests that the steam flowing in the steam turbine 10 before modification be supplied with steam of the third pressure and the third temperature. Assume that the steam passing through the third blade row stage in the high-pressure steam turbine section 20 is at the third pressure and the third temperature. In this case, Figure 7 and Figure 8 As shown, the third blade row stage and all blade row stages closer to the axial upstream side Dau than the third blade row stage in the high-pressure steam turbine section 20 are left in advance, and on the other hand, all blade row stages closer to the axial downstream side Dad than the third blade row stage are removed (blade removal process S1). Specifically, the stationary blade row 36 and the moving blade row 25 constituting the fourth blade row stage are removed. Furthermore, the stationary blade row 66 and the moving blade row 55 constituting all blade row stages in the low-pressure steam turbine section 50 are removed. As a result, the moving blade row 25 constituting the third blade row stage becomes the final stage moving blade row 25z in the steam turbine 10c after the transformation.

[0088] Next, the partition plate 80b as a partition member is used to partition the annular high-pressure steam flow path 35 at a position closer to the downstream side Dad of the axis than the final stage moving blade row 25z (flow path partitioning step 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 as it approaches the downstream side Dad of the axis. The outer end 82b is provided at the end of the radially outer side Dro of the partition plate body 81b and the end of the axis upstream side Dau. The outer end 82b is annular with the axis Ar as the center. In addition, the inner end 83b is provided at the end of the radially inner side Dri of the partition plate body 81b and the end of the axis downstream side Dad. The inner end 83b is annular with the axis Ar as the center. The inner end portion 83b has a partition plate seal 84b that seals between the partition plate 80b and the intermediate shaft seal device 43. The annular outer end portion 82b is fitted into the stationary blade row assembly portion 32, which is an annular groove, and is assembled to the high-pressure rotor housing 30. The stationary blade row assembly portion 32 is a stationary blade row assembly portion 32 to which the outer ring 38 of the stationary blade row 36 of the fourth blade row stage removed in the blade removal step S1 among the plurality of stationary blade row assembly portions 32 constituting the high-pressure rotor housing 30 is assembled. The partition plate seal 84b of the annular inner end portion 83b contacts the seal support 43b of the intermediate shaft seal device 43 in a manner that is movable in the axial direction Da relative to the intermediate shaft seal device 43.

[0089] In the present embodiment, the inner end 83b of the partition plate 80b is brought into contact with the intermediate shaft seal device 43 as a stationary part. However, the inner end 83b of the partition plate 80b may be brought into contact with the vicinity of a portion of the high-pressure rotor housing 30 to which the intermediate shaft seal device 43 is connected. In this case, the stationary parts with which the inner end 83b is brought into contact include the low-pressure shaft seal device 72 and the high-pressure rotor housing 30.

[0090] 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 83b of the partition plate 80b can move in the axial direction Da relative to the intermediate shaft seal device 43. Therefore, the inner end 83b of the partition plate 80b can move in the direction including the component of the direction in which the partition plate 80b expands. Therefore, even if the partition plate 80b is extended by heat, the inner end 83b of the partition plate 80b moves, allowing the extension of the partition plate 80b.

[0091] Next, an exhaust flow path is set in the high-pressure steam flow path 35, and the exhaust flow path can guide the steam in the upstream space 35u closer to the final stage moving blade row 25z side than the position where the high-pressure steam flow path 35 is divided by the partition plate 80b to the outside of the high-pressure rotor housing 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 of the steam supply client. Therefore, the exhaust pipe 85b forms a fourth steam supply line for conveying the steam in the upstream space 35u to the fourth steam utilization device 95d.

[0092] Next, similarly to the first embodiment, the exhaust port 77 of the exhaust casing 75 is blocked by the blocking plate 86 (exhaust port blocking step S4). In addition, in the exhaust port blocking step 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 casing 60 so that steam does not flow in the first steam supply line 96a. It should be noted that, similarly to the blocking plate 86, a drainage discharge pipe 89 is preferably provided in the blind flange 88.

[0093] Next, similarly to the first embodiment, a thermometer 93 capable of sensing the temperature of the downstream space 35d and a spray nozzle 90 capable of spraying cooling water into the downstream space 35d are provided (spray nozzle installation step S5). A cooling water line 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 line 91 is provided in the cooling water line 91. When the temperature sensed by the thermometer 93 is equal to or higher than a predetermined temperature, the regulating valve 92 is opened.

[0094] As described above, the modification of the steam turbine 10 according to the present embodiment is completed.

[0095] In the steam turbine 10c obtained by the modification described above, all the blade row stages closer to the axis downstream side Dad than the third blade row stage in the high-pressure steam turbine section 20 before the modification are missing. However, in the steam turbine 10c obtained by the modification, the stationary blade row mounting parts 32, 62 to which the stationary blade rows 36, 66 constituting the removed blade row stages were mounted and the moving blade row mounting parts 23, 53 to which the moving blade rows 25, 55 constituting the removed blade row stages were mounted remain. In addition, the steam turbine 10a 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 10c before the modification.

[0096] As described above, in this embodiment, as in the first embodiment, the steam from the steam turbine 10c is not transported to the condenser 99, but is transported to the fourth steam utilization device 95d. Therefore, the heat loss generated in the process of restoring the steam to water through the condenser 99 disappears, and the heat of the steam from the boiler can be effectively utilized.

[0097] Furthermore, in the present embodiment, as in the first embodiment, by appropriately selecting the blade row stage to be removed, steam of a pressure and temperature corresponding to the requirements of the steam utilization side can be fed to the steam utilization equipment.

[0098] "Variation"

[0099] The inner end portions 83, 83a, 83b of the partition plates 80, 80a, 80b of the above-mentioned embodiments can move in the axial direction Da to allow the partition plates 80, 80a, 80b to extend in the direction including the radial direction Dr and 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 the direction includes the radial direction Dr and the axial direction Da in which the partition plates 80, 80a, 80b extend. Therefore, the inner end portions 83, 83a, 83b of the partition plates 80, 80a, 80b can also move in the radial direction Dr.

[0100] 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 part as in the first embodiment. In addition, in the first and third embodiments, the inner end 83, 83b of the partition plates 80, 80b is in contact with a stationary part. However, the inner end 83, 83b of these partition plates 80, 80b may be in contact with the rotor shafts 22, 52 as in the second embodiment.

[0101] 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 space 35u and 65u can be guided to the outside of the rotor housing 30 and 60, the exhaust pipes 85 and 85b may not be connected to the partition plates 80 and 80b. For example, Fig. 9 As shown, a port 63x capable of discharging the steam in the upstream space 65u to the outside of the low-pressure rotor housing 60 may be provided in the low-pressure rotor housing 60, and the exhaust pipe 85c may be connected to the port 63x. It should be noted that, for example, a port 63x capable of discharging the steam in the upstream space 65u to the outside of the low-pressure rotor housing 60 may be formed in advance in the low-pressure rotor housing 60 to discharge the steam generated in the upstream space 65u.

[0102] In the flow path partitioning step S2 of the third embodiment, the partition plate 80b is used as a partition member to partition the annular high-pressure steam flow path 35 at a position closer to the axial downstream side Dad than the final stage rotor blade row 25z. Fig.10 As shown, in the flow path partitioning step S2, the annular high-pressure steam flow path 35 may be partitioned by closing the low-pressure steam valve 71 instead of the partitioning plate 80b. Thus, in this case, the low-pressure steam valve 71 forms a partition member. It should be noted that, in this case, the downstream steam flow path 70p may be blocked by a blocking plate 86b at a position closer to the downstream side in the direction of steam flow than the position where the low-pressure steam valve 71 is provided, instead of blocking the exhaust port 77 of the exhaust casing 75 with a blocking plate 86. When the blocking plate 86b is provided in the downstream steam flow path 70p, it is preferable to provide a drainage discharge pipe on 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 steam flow path 70p, and a spray nozzle 90 capable of spraying cooling water into the space may be provided.

[0103] In each of the above embodiments, there is only one exhaust flow path that guides the steam in the upstream space 35u, 65u to the outside of the rotor housing 30, 60. However, the exhaust flow path may be multiple. For example, in the first embodiment, one exhaust pipe 85 forming the exhaust flow path is connected to the partition plate 80, but multiple exhaust pipes 85 may be connected to the partition plate 80. In this case, for example, the exhaust pipe 85 is connected at each of the 3 o'clock and 9 o'clock positions when viewed from the axial direction Da.

[0104] In the steam turbines 10a, 10b, 10c after the reconstruction of the above embodiment, the stationary blade row mounting parts 32, 62 to which the stationary blade rows 36, 66 constituting the blade row stage removed by reconstruction were mounted and the moving blade row mounting parts 23, 53 to which the moving blade rows 25, 55 constituting the blade row stage removed by reconstruction were mounted remain. However, in the process of reconstruction, the parts of the stationary blade row mounting parts 32, 62 to which the stationary blade rows 36, 66 are not mounted may be removed from the rotor casings 30, 60. In addition, the parts of the moving blade row mounting parts 23, 53 to which the moving blade rows 25, 55 are not mounted may be removed from the rotor shafts 22, 52.

[0105] In the above embodiment, the exhaust port blocking step S4 and the spray nozzle setting step S5 are performed. However, the exhaust port blocking step S4 and the spray nozzle setting step S5 may be omitted. In particular, in the case of the third embodiment, if the low-pressure steam valve 71 is closed in advance after the modification, steam hardly flows from the low-pressure steam valve 71 to the downstream side, and therefore, the exhaust port blocking step S4 and the spray nozzle setting step S5 may be omitted.

[0106] The present disclosure is not limited to the above-described embodiments, and various additions, changes, substitutions, partial deletions, etc. may be made without departing from the conceptual idea and gist of the present invention as derived from the claims and their equivalents.

[0107] [Note]

[0108] The modification method of the steam turbine 10 according to the above-mentioned embodiment and the modified example can be understood as follows, for example.

[0109] (1) The steam turbine reconstruction method according to the first aspect is targeted at the following steam turbine 10 .

[0110] The steam turbine 10 to be modified includes: a rotor 21, 51 rotatable around an axis Ar; a rotor case 30, 60 covering the outer circumference of the rotor 21, 51; and a plurality of stationary blade rows 36, 66 provided on the inner circumference of the rotor case 30, 60 and arranged in an axial direction Da along which the axis Ar extends. The rotor 21, 51 includes: a rotor shaft 22, 52 extending in the axial direction Da around the axis Ar; and a plurality of moving blade rows 25, 55 provided on the rotor shaft 22, 52. The plurality of moving blade rows 25, 55 are respectively arranged on the axial downstream side Dad in the axial direction Da of any one of the plurality of stationary blade rows 36, 66.

[0111] In the modification method of the steam turbine 10, a blade removal step S1 is performed to remove a plurality of moving blade rows 25, 55 including the moving blade row 25, 55 closest to the axial downstream side Dad and adjacent to each other in the axial direction Da, or the moving blade row 25, 55 closest to the axial downstream side Dad, from among the plurality of moving blade rows 25, 55, and to remove a stationary blade row 36, 66 adjacent to the axial upstream side Dau in the axial direction Da of each of the one or more moving blade rows 25, 55 to be removed, leaving at least one of the plurality of moving blade rows 25, 55 closest to the axial upstream side Dad. au's moving blade row 25, 55, and leaving at least the stationary blade row 36, 66 closest to the upstream side Dau of the axis among the multiple stationary blade rows 36, 66; and a flow path separation step S2, in which the annular steam flow path 35, 65 formed between the inner circumference of the rotor casing 30, 60 and the outer circumference of the rotor shaft 22, 52 or the downstream side steam flow path 70p connected to the steam flow path 35 is separated at a position closer to the downstream side Dad of the axis than the moving blade row 25, 55 closest to the downstream side Dad of the axis among the one or more moving blade rows 25, 55 left after the blade removal step S1, i.e., the final-stage moving blade row 25z, 55z.

[0112] In this embodiment, the steam from the steam turbine 10 can be delivered to the steam utilization equipment in the upstream space 35u, 65u closer to the final stage rotor blade row 25z, 55z side than the position dividing the steam flow paths 35, 65, without being delivered to the condenser 99. Therefore, in this embodiment, the heat loss generated in the process of returning the steam to water through the condenser 99 is eliminated, and the heat of the steam from the boiler can be effectively utilized.

[0113] Furthermore, in the present embodiment, by appropriately selecting the blade row stage to be removed, steam having a pressure and a temperature corresponding to the requirements of the steam utilization side can be delivered to the steam utilization equipment.

[0114] (2) In the steam turbine modification method of the second embodiment,

[0115] In the modification method of the steam turbine 10 of the first aspect, the following exhaust flow path setting step S3 is performed: an exhaust flow path is set in the steam flow path 35, 65, and the exhaust flow path can guide the steam in the space closer to the final stage rotor blade row 25z, 55z side than the position dividing the steam flow path 35, 65 or the downstream side steam flow path 70p to the outside of the rotor casing 30, 60. In the exhaust flow path setting step S3, the pipes 85, 85b forming the exhaust flow path are provided.

[0116] (3) In the steam turbine modification method of the third embodiment,

[0117] In the modification method of the steam turbine 10 of the first aspect, the rotor housing 60 is pre-formed with an air extraction port 63, and the air extraction port 63 can guide the steam in the space closer to the last-stage moving blade row 25z, 55z than the position dividing the steam flow path 35, 65 or the downstream-side steam flow path 70p to the outside of the rotor housing 60. In the modification method of the steam turbine of the third aspect, the following exhaust flow path setting step S3a is performed: an exhaust flow path is set in the steam flow path 35, 65 or the downstream-side steam flow path 70p, and the exhaust flow path can guide the steam in the space closer to the last-stage moving blade row 55z than the position dividing the steam flow path 35, 65 or the downstream-side steam flow path 70p to the outside of the rotor housing 60. In the exhaust flow path setting step S3a, the air extraction port 63 is set as at least a part of the exhaust flow path.

[0118] (4) In the steam turbine modification method of the fourth aspect,

[0119] In the steam turbine 10 modification method of any one of the first to third aspects, the steam turbine 10 includes a steam valve 71 capable of partitioning the downstream steam flow path 70p. In the flow path partitioning step S2, the downstream steam flow path 70p is partitioned by closing the steam valve 71.

[0120] (5) In the steam turbine modification method of the fifth embodiment,

[0121] In the modification method of the steam turbine 10 of any one of the first to third aspects, in the flow path partitioning step S2, the steam flow paths 35, 65 are partitioned using partition plates 80, 80a, 80b. The partition plates 80, 80a, 80b have inner ends 83, 83a, 83b, which are ends on the radial inner side Dri in the radial direction Dr relative to the axis Ar, and outer ends 82, 82a, 82b, which are ends on the radial outer side Dro in the radial direction Dr. In the flow path partitioning step S2, the outer ends 82, 82a, 82b of the partition plates 80, 80a, 80b are connected to the rotor casings 30, 60.

[0122] (6) In the steam turbine modification method of the sixth aspect,

[0123] In the modification method of the steam turbine 10 of the fifth scheme, in the flow path partitioning step S2, in the rotor casing 30, 60, the stator blade row assembly portion 32, 62 for assembling the stator blade row 36, 66 closest to the upstream side Dau of the axis among one or more stator blade rows 36, 66 removed in the blade removal step S1 is connected to the outer end portion 82, 82a, 82b of the partition plate 80, 80a, 80b.

[0124] In this embodiment, the outer ends 82, 82a, 82b of the partition plates 80, 80a, 80b are mounted on the stationary blade row mounting portions 32, 62 formed in the rotor casings 30, 60 of the steam turbine 10 before modification. Therefore, in this embodiment, modification of the rotor casings 30, 60 to which the outer ends 82b of the partition plates 80, 80a, 80b are mounted can be suppressed to a minimum.

[0125] (7) In the steam turbine modification method of the seventh embodiment,

[0126] In the modification method of the steam turbine 10 of the fifth or sixth scheme, 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 final stage moving blade row 25z, 55z, and has a portion along the outer peripheral surface of the rotor shaft 22, 52.

[0127] In the flow path partitioning step S2 , the inner end portions 83 , 83 b of the partition plates 80 , 80 b are brought into contact with the stationary component.

[0128] 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 peripheral surface of the rotor shaft 22 and 52. Therefore, in this embodiment, compared with the 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 suppress the leakage of steam from between the inner end portions 83 and 83b and the contacting object.

[0129] (8) In the steam turbine modification method of the eighth aspect,

[0130] In the modification method of the steam turbine 10 of the seventh scheme, in the flow path partitioning step S2, the inner ends 83, 83b of the partition plates 80, 80b are brought into contact with the stationary parts in such a manner that the inner ends 83, 83b of the partition plates 80, 80b can move in a direction including a directional component of the expansion of the partition plates 80, 80b.

[0131] 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 component of the direction in which the partition plates 80, 80b expand. Therefore, in this embodiment, even when the partition plates 80, 80b are extended by heat, the inner end portions 83, 83b of the partition plates 80, 80b move, thereby allowing the partition plates 80, 80b to extend.

[0132] (9) In the steam turbine modification method of the ninth aspect,

[0133] In the modification method of the steam turbine 10 of the seventh or eighth embodiment, the stationary part is a shaft sealing device 42, 43 which faces the outer peripheral surface of the rotor shaft 22, 52 and can suppress the outflow of steam to the downstream side Dad of the axis thereof.

[0134] (10) In the steam turbine modification method of claim 10,

[0135] In the method for modifying the steam turbine 10 of any one of the first to ninth aspects, the steam turbine 10 includes an exhaust casing 75 capable of guiding the steam flowing in the steam flow path 65 to the condenser 99. An exhaust port blocking step S4 of blocking the exhaust port 77 in the exhaust casing 75 for discharging steam to the condenser 99 is performed.

[0136] In this embodiment, even if a portion of the steam in the upstream space 65u on the side closer to the final-stage moving blade row 55z than the position where the steam flow path 65 is divided flows into the downstream space 65d on the side farther from the final-stage moving blade row 55z than the position where the steam flow path 65 is divided, the steam can be prevented from flowing into the condenser 99.

[0137] (11) In the steam turbine modification method of the eleventh scheme,

[0138] In the modification method of the steam turbine 10 of any one of the first to tenth schemes, the following spray nozzle setting step S5 is performed: in the steam flow path 35, 65, a spray nozzle 90 capable of spraying cooling water is set in the space on the side away from the final stage moving blade row 25z, 55z compared to the position that separates the steam flow path 35, 65.

[0139] In the steam turbine 10 before the modification, the temperature of the steam in the upstream space 35u, 65u in the steam flow path 35, 65 is higher than the temperature of the steam passing through the moving blade row 25, 55 closest to the downstream side Dad of the axis. In the steam turbine 10 before the modification, the pressure of the steam in the upstream space 35u, 65u in the steam flow path 35, 65 is higher than the pressure of the steam passing through the moving blade row 25, 55 closest to the downstream side Dad of the axis. Therefore, when a part of the steam in the upstream space 35u, 65u flows into the downstream space 35d, 65d, there is a possibility that the casing defining the downstream space 35d, 65d and the casing defining the space on the downstream side thereof may be damaged. Therefore, in the present embodiment, a spray nozzle 90 is provided which can spray cooling water into the downstream side space 35d, 65d, so that 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 the prescribed temperature, and the pressure in the downstream side space 35d, 65d will not rise above the prescribed pressure.

[0140] The steam turbines 10a, 10b, and 10c after modification according to the above-mentioned embodiment and the modified example are understood as follows, for example.

[0141] (12) The steam turbine of the twelfth option has:

[0142] The rotor 21, 51 is rotatable around the axis Ar; the rotor housing 30, 60 covers the outer circumference of the rotor 21, 51; a plurality of stationary blade rows 36, 66 or one stationary blade row 36, 66 is provided on the inner circumference of the rotor housing 30, 60 and arranged in the axial direction Da along which the axis Ar extends; a partition member 80, 80a, 80b, 71 partitions the steam flow path 35, 65 or the downstream steam flow path 70p communicating with the steam flow path 35; and an exhaust flow path forming portion forms an exhaust flow path capable of guiding steam to the outside of the rotor housing 30, 60. The rotor 21, 51 has a rotor shaft 22, 52 extending in the axial direction Da around the axis Ar; and a plurality of moving blade rows 25, 55 or one moving blade row 25, 55 provided on the rotor shaft 22, 52. The one or more moving blade rows 25, 55 are respectively arranged on the axial downstream side Dad in the axial direction Da of any one of the one or more stationary blade rows 36, 66. The steam flow path 35, 65 is an annular flow path formed between the inner peripheral side of the rotor housing 30, 60 and the outer peripheral side of the rotor shaft 22, 52. The partition member 80, 80a, 80b, 71 partitions the steam flow path 35, 65 or the downstream side steam flow path 70p at a position closer to the axial downstream side Dad than the moving blade row 25, 55 closest to the axial downstream side Dad among the one or more moving blade rows 25, 55, that is, the final stage moving blade row 25z, 55z. The exhaust flow path can guide steam in a space closer to the final-stage blade row 25z, 55z than a position dividing the steam flow path 35, 65 or the downstream-side steam flow path 70p to the outside of the rotor casing 30, 60.

[0143] (13) In the steam turbine of claim 13,

[0144] In the steam turbine 10a, 10b, 10c of the twelfth aspect, the rotor casing 30, 60 has a stationary blade row mounting portion 32, 62 on the downstream side Dad of the axis line relative to the final stage moving blade row 25z, 55z, to which the stationary blade row 36, 66 is mounted but not mounted. The rotor shaft 22, 52 has a moving blade row mounting portion 23, 53 on the downstream side Dad of the axis line relative to the final stage moving blade row 25z, 55z, to which the moving blade row 25, 55 is mounted but not mounted.

[0145] (14) In the steam turbine of claim 14,

[0146] In the steam turbine 10a, 10b, 10c of the twelfth or thirteenth aspect, the partition member 80, 80a, 80b, 71 includes a steam valve 71 capable of partitioning the downstream steam flow path 70p. The steam valve 71 is closed when partitioning the downstream steam flow path 70p.

[0147] (15) In the steam turbine of the fifteenth embodiment,

[0148] In the steam turbine 10a, 10b, 10c of the twelfth or thirteenth aspect, a partition plate 80, 80a, 80b is provided as the partition member 80, 80a, 80b, 71 for partitioning the steam flow path 35, 65. The partition plate 80, 80a, 80b has an inner end portion 83, 83a, 83b which is an end portion on the radial inner side Dri in the radial direction Dr relative to the axis Ar, and an outer end portion 82b which is an end portion on the radial outer side Dro in the radial direction Dr. The outer end portion 82b of the partition plate 80, 80a, 80b is connected to the rotor housing 30, 60.

[0149] (16) In the steam turbine of claim 16,

[0150] In the steam turbine 10a, 10b, 10c according to the thirteenth aspect,

[0151] The partition plates 80, 80a, 80b have inner end portions 83, 83a, 83b, which are radially inner end portions Dri in a radial direction Dr relative to the axis Ar, and outer end portions 82b, which are radially outer end portions Dro in the radial direction Dr. The outer end portions 82b of the partition plates 80, 80a, 80b are connected to the stationary blade row mounting portions 32, 62 of the rotor housings 30, 60.

[0152] (17) In the steam turbine of claim 17,

[0153] In the steam turbine 10a, 10c of the fifteenth or sixteenth aspect, the steam turbine 10a, 10c includes a stationary component which is arranged at a position closer to the axis downstream side Dad than the final stage blade row 25z, 55z and has a portion along the outer peripheral surface of the rotor shaft 22, 52. The inner end portion 83, 83b of the partition plate 80, 80b contacts the stationary component.

[0154] (18) In the steam turbine of claim 18,

[0155] In the steam turbine 10a, 10c of the seventeenth aspect,

[0156] The inner end portions 83 and 83b of the partition plates 80 and 80b are in contact with the stationary part so that the inner end portions 83 and 83b of the partition plates 80 and 80b can move in a direction including a directional component in which the partition plates 80 and 80b expand.

[0157] (19) In the steam turbine of claim 19,

[0158] In the steam turbine 10a, 10c of the seventeenth or eighteenth aspect, the stationary part is a shaft sealing device 42, 43 which faces the outer peripheral surface of the rotor shaft 22, 52 and suppresses outflow of steam to the downstream side Dad of the axis line thereof.

[0159] (20) In the steam turbine of the twentieth embodiment,

[0160] In the steam turbine 10a, 10b, 10c of any one of the twelfth to nineteenth schemes, the steam turbine 10a, 10b, 10c comprises: an exhaust casing 75 capable of discharging the steam flowing in the steam flow path 35, 65 to the condenser 99; and a blocking plate 86, in the exhaust casing 75, blocking the exhaust port 77 capable of discharging steam to the condenser 99.

[0161] (21) In the steam turbine of claim 21,

[0162] In the steam turbine 10a, 10b, 10c of any one of the twelfth to twentieth embodiments, there is a spray nozzle 90, which can spray cooling water in the steam flow path 35, 65 to the space on the side farther from the final stage moving blade row 25z, 55z than the partition plate 80, 80a, 80b.

[0163] Industrial Applicability

[0164] According to one aspect of the present disclosure, steam having a pressure and a temperature corresponding to a requirement of a steam utilization side can be delivered to a steam utilization device.

[0165] Description of Reference Numerals

[0166] 10: Steam turbine (before transformation);

[0167] 10a, 10b, 10c: (modified) steam turbine;

[0168] 11: Steam turbine rotor;

[0169] 15: Steam turbine casing;

[0170] 16: first bearing;

[0171] 17: Second bearing;

[0172] 20: High pressure steam turbine section;

[0173] 21: High pressure rotor;

[0174] 22: High pressure rotor shaft;

[0175] 23: Moving blade row assembly;

[0176] 25: moving blade row;

[0177] 25z: final stage rotor blade row;

[0178] 26: moving leaves;

[0179] 27: blade body;

[0180] 28: Leaf root;

[0181] 30: high pressure rotor housing;

[0182] 32: Stationary blade row assembly;

[0183] 33: High pressure steam exhaust port;

[0184] 35: high pressure steam flow path;

[0185] 35u: upstream side space;

[0186] 35d: downstream side space;

[0187] 36: static blade row;

[0188] 37: blade body;

[0189] 38: Outer ring;

[0190] 39: inner ring;

[0191] 40: High-pressure steam pipe;

[0192] 41: High pressure steam valve;

[0193] 42: High pressure shaft sealing device;

[0194] 42s: seals;

[0195] 42b: seal support platform;

[0196] 43: Intermediate shaft sealing device;

[0197] 43s: seals;

[0198] 43b: seal support platform;

[0199] 50: Low-pressure steam turbine section;

[0200] 51: low pressure rotor;

[0201] 52: low pressure rotor shaft;

[0202] 53: Moving blade row assembly;

[0203] 55: moving blade row;

[0204] 55z: final stage rotor blade row;

[0205] 56: moving leaves;

[0206] 57: blade body;

[0207] 58: Leaf root;

[0208] 60: low pressure rotor housing;

[0209] 61: Shell body;

[0210] 62: Stationary blade row assembly;

[0211] 63: air extraction port;

[0212] 63x: mouth;

[0213] 64: Diffuser;

[0214] 64o: Outer diffuser;

[0215] 64i: Inboard diffuser;

[0216] 65: low pressure steam flow path;

[0217] 65u: upstream side space;

[0218] 65d: downstream side space;

[0219] 66: static blade row;

[0220] 67: blade body;

[0221] 68: Outer ring;

[0222] 69: inner ring;

[0223] 70: low pressure steam pipe;

[0224] 70p: downstream steam flow path;

[0225] 71: low pressure steam valve (separating member);

[0226] 72: low pressure shaft sealing device;

[0227] 72s: seals;

[0228] 72b: seal support platform;

[0229] 75: exhaust housing;

[0230] 76: Exhaust space;

[0231] 77: Exhaust port;

[0232] 80, 80a, 80b: partition plate (partition member);

[0233] 81, 81a, 81b: partition plate body;

[0234] 82, 82a, 82b: outer ends;

[0235] 83, 83a, 83b: inner end;

[0236] 84, 84a, 84b: separator plate seal;

[0237] 85, 85b, 85c: exhaust pipe (exhaust flow path forming portion);

[0238] 86, 86b: blocking plate;

[0239] 87: drainage discharge pipe;

[0240] 88: Blind flange;

[0241] 89: drainage discharge pipe;

[0242] 90: spray nozzle;

[0243] 91: Cooling water pipeline;

[0244] 92: regulating valve;

[0245] 93: Thermometer;

[0246] 95a: first steam utilization equipment;

[0247] 96a: first steam supply line;

[0248] 95b: second steam utilization equipment;

[0249] 95c: Third steam utilization equipment;

[0250] 96c: third steam supply line;

[0251] 95d: Fourth steam utilization equipment;

[0252] 99: condenser;

[0253] Ar: axis;

[0254] Da: axis direction;

[0255] Dau: upstream side of the axis;

[0256] Dad: downstream side of the axis;

[0257] Dc: circumferential direction;

[0258] Dr: radial;

[0259] Dri: radial medial;

[0260] Dro: radially outward.

Claims

1. A method for modifying a steam turbine, wherein: The steam turbine comprises: The rotor can rotate around the axis; a rotor housing covering an outer peripheral side of the rotor; and A plurality of stationary blade rows are provided on the inner peripheral side of the rotor housing and are arranged in the axial direction along which the axis extends. The rotor includes: a rotor shaft extending in the axial direction with the axis as the center; and a plurality of rotor blade rows provided on the rotor shaft. The plurality of moving blade rows are respectively arranged on the axial downstream side of any one of the plurality of stationary blade rows in the axial direction, In the steam turbine modification method, the following steps are performed: a blade removal step of removing a plurality of moving blade rows including a moving blade row closest to the downstream side of the axis and adjacent to each other in the axial direction or a moving blade row closest to the downstream side of the axis, and removing a stationary blade row adjacent to the upstream side of the axis in the axial direction of each of the one or more moving blade rows to be removed, leaving at least a moving blade row closest to the upstream side of the axis, and leaving at least a stationary blade row closest to the upstream side of the axis, among the plurality of moving blade rows; as well as A flow path separation process is to separate an annular steam flow path formed between the inner circumference of the rotor casing and the outer circumference of the rotor shaft or a downstream steam flow path connected to the steam flow path at a position closer to the downstream side of the axis than the final-stage moving blade row among the one or more moving blade rows remaining after the blade removal process.

2. The steam turbine modification method according to claim 1, wherein: performing the following exhaust flow path setting step: setting an exhaust flow path in the steam flow path, the exhaust flow path being capable of guiding steam in a space closer to the final-stage rotor blade row side than a position dividing the steam flow path or the downstream-side steam flow path to the outside of the rotor casing, In the exhaust flow path setting step, a pipe forming the exhaust flow path is provided.

3. The steam turbine modification method according to claim 1, wherein: The rotor housing is pre-formed with an air extraction port, which can guide steam in a space closer to the final-stage rotor blade row than a position dividing the steam flow path or the downstream-side steam flow path to the outside of the rotor housing. In the steam turbine modification method, the following exhaust flow path setting step is performed: an exhaust flow path is set in the steam flow path or the downstream side steam flow path, the exhaust flow path being capable of guiding steam in a space closer to the final stage moving blade row side than a position dividing the steam flow path or the downstream side steam flow path to the outside of the rotor casing, In the exhaust flow path setting step, the exhaust port is set as at least a part of the exhaust flow path.

4. The steam turbine modification method according to 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 partitioning step, the downstream steam flow path is partitioned by closing the steam valve.

5. The steam turbine modification method according to any one of claims 1 to 3, wherein: In the flow path partitioning step, a partition plate is used to partition the steam flow path. The partition plate has an inner end portion, which is an end portion on the radial inner side in the radial direction relative to the axis, and an outer end portion, which is an end portion on the radial outer side in the radial direction. In the flow path partitioning step, the outer end portion of the partition plate is connected to the rotor case.

6. The steam turbine modification method according to claim 5, wherein: In the flow path partitioning step, the outer end portion of the partition plate is connected to a stationary blade row mounting portion in the rotor casing to which a stationary blade row most upstream of the axis among the one or more stationary blade rows removed in the blade removing step is mounted.

7. The steam turbine modification method according to claim 5, wherein: The steam turbine includes a stationary part, the stationary part being arranged at a position downstream of the axis line relative to the final stage rotor blade row and having a portion along the outer peripheral surface of the rotor shaft. In the flow path partitioning step, the inner end portion of the partition plate is brought into contact with the stationary component.

8. The steam turbine modification method according to claim 7, wherein: In the flow path partitioning step, the inner end of the partition plate is brought into contact with the stationary component so that the inner end of the partition plate can move in a direction including a directional component in which the partition plate expands.

9. The steam turbine modification method according to claim 7, wherein: The stationary component is a shaft sealing device that faces the outer peripheral surface of the rotor shaft and can suppress the outflow of steam to the downstream side of the axis of the stationary component.

10. The steam turbine modification method according to any one of claims 1 to 3, wherein: The steam turbine includes an exhaust casing capable of guiding the steam flowing in the steam flow path to a condenser. An exhaust port blocking step of blocking an exhaust port through which steam is discharged to the condenser in the exhaust casing is performed.

11. The steam turbine modification method according to any one of claims 1 to 3, wherein: The following spray nozzle installation step is performed: installing a spray nozzle capable of spraying cooling water in a space on the side farther from the final-stage blade row than a position dividing the steam flow path or the downstream-side steam flow path.

12. A steam turbine comprising: The rotor can rotate around the axis; A rotor housing covering the outer circumference of the rotor; A plurality of stationary blade rows or a single stationary blade row are provided on the inner peripheral side of the rotor housing and arranged in the axial direction in which the axis extends; a partition member that partitions the steam flow path or a downstream steam flow path that communicates with the steam flow path; and The exhaust flow path forming portion is formed with an exhaust flow path capable of guiding steam to the outside of the rotor housing, The rotor comprises: a rotor shaft extending in the axial direction with the axis as the center; and a plurality of blade rows or one blade row provided on the rotor shaft. The one or more moving blade rows are respectively arranged on the axial downstream side of any one of the one or more stationary blade rows in the axial direction, The steam flow path is an annular flow path formed between the inner peripheral side of the rotor housing and the outer peripheral side of the rotor shaft. The partition member partitions the steam flow path or the downstream steam flow path at a position closer to the downstream side of the axis than the last-stage blade row, which is the blade row closest to the downstream side of the axis among the one or more blade rows. The exhaust flow path can guide steam in a space closer to the final-stage blade row than a position dividing the steam flow path or the downstream-side steam flow path to the outside of the rotor casing.

13. The steam turbine according to claim 12, wherein: The rotor housing has a stationary blade row mounting portion on the downstream side of the axis relative to the final stage moving blade row, to which the stationary blade row can be mounted but is not mounted. The rotor shaft has a blade row mounting portion to which a blade row can be mounted but to which no blade row is mounted, on a downstream side of the axis line relative to the final-stage blade row.

14. The steam turbine according to claim 12, wherein: The partition member includes a steam valve capable of partitioning the downstream steam flow path. The steam valve is in a closed state while partitioning the downstream steam flow path.

15. The steam turbine according to claim 12, wherein: The partition member includes a partition plate for partitioning the steam flow path. The partition plate has an inner end portion, which is an end portion on the radial inner side in the radial direction relative to the axis, and an outer end portion, which is an end portion on the radial outer side in the radial direction. The outer end portion of the partition plate is connected to the rotor housing.

16. The steam turbine according to claim 13, wherein: The partition member includes a partition plate for partitioning the steam flow path. The partition plate has an inner end portion, which is an end portion on the radial inner side in the radial direction relative to the axis, and an outer end portion, which is an end portion on the radial outer side in the radial direction. The outer end portion of the partition plate is connected to the stationary blade row mounting portion of the rotor housing.

17. The steam turbine according to claim 15, wherein: The steam turbine includes a stationary part, the stationary part being arranged at a position downstream of the axis line relative to the final stage rotor blade row and having a portion along the outer peripheral surface of the rotor shaft. The inner end portion of the partition plate is in contact with the stationary component.

18. The steam turbine according to claim 17, wherein: The inner end portion of the partition plate is in contact with the stationary component so as to be movable in a direction including a directional component in which the partition plate expands.

19. The steam turbine according to claim 17 or 18, wherein: The stationary component is a shaft sealing device that faces the outer peripheral surface of the rotor shaft and suppresses outflow of steam to the downstream side of the axis of the stationary component.

20. The steam turbine according to any one of claims 12 to 18, wherein: The steam turbine comprises: an exhaust casing capable of exhausting the steam flowing in the steam flow path to a condenser; and A blocking plate is provided in the exhaust housing to block an exhaust port through which steam can be discharged toward the condenser.

21. The steam turbine according to any one of claims 12 to 18, wherein: The steam turbine includes a spray nozzle capable of spraying cooling water toward a space on a side farther from the final-stage rotor blade row than the partition member in the steam flow path or the downstream-side steam flow path.

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