FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: STEAM TURBINE FACILITY AND COMBINED CYCLE PLANT
2. Applicant(s)
NAME NATIONALITY ADDRESS
MITSUBISHI POWER, LTD. Japanese 3-1, Minatomirai 3-Chome, Nishiku,
Yokohama-shi, Kanagawa
2208401, Japan
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.
TECHNICAL FIELD
[0001] The present disclosure relates to a steam turbine facility and a combined
cycle plant.

BACKGROUND
[0002] In a large-capacity steam turbine used for a combined cycle plant or the
like, in order to deal with a large amount of inflow steam, besides a turbine blade
row and a turbine into which high-pressure main steam flows, a turbine blade row
and a turbine into which lower-pressure steam flows may be provided.
[0003] For example, Patent Document 1 discloses a four-flow exhaust type steam
turbine power generation plant, where a high-pressure steam turbine to which highpressure
steam is introduced, an intermediate-pressure steam turbine to which
lower-pressure steam is introduced, two double-flow exhaust type low-pressure
steam turbine to which further-lower-pressure steam is introduced, and a generator are disposed on a single shaft.
Citation List
Patent Literature
[0004]
Patent Document 1: JP2006-22343A

SUMMARY
Technical Problem
[0005] Meanwhile, conventionally, in a large-capacity steam turbine facility, in order to improve performance, a configuration is generally adopted where turbine blade rows such as a high-pressure turbine blade row, an intermediate-pressure turbine blade row, and a low-pressure turbine blade row are accommodated in different casings. For example, in the case of a high-performance steam turbine of a four-flow exhaust type 5 including a high-pressure turbine blade row, an intermediate-pressure turbine blade row, and two sets of double-flow exhaust type low-pressure turbine blade rows, a four-casing configuration has generally been adopted.
With the configuration where the respective turbine blade rows are thus
accommodated in the different casings, it is possible to achieve the highperformance
steam turbine. On the other hand, however, the total length of the
turbine increases, and thus a facility cost of a building or the like where the steam turbines are accommodated tends to increase.
[0006] In view of the above, an object of at least one embodiment of the present invention is to provide a steam turbine facility capable of reducing the facility cost
while having high performance and a combined cycle plant including the same.
Solution to Problem
[0007] (1) A steam turbine facility according to at least one embodiment of the present invention includes a rotor shaft, a high-pressure turbine blade row and an intermediate-pressure turbine blade row disposed on the rotor shaft, a first lowpressure turbine blade row and a second low-pressure turbine blade row disposed on the rotor shaft on both sides of the intermediate-pressure turbine blade row,
respectively, and a third low-pressure turbine blade row and a fourth low-pressure turbine blade row disposed on the rotor shaft on both sides of the high-pressure turbine blade row, respectively. The steam turbine facility is configured such that steam having passed through the intermediate-pressure turbine blade row is divided
to flow into the first low-pressure turbine blade row, the second low-pressure turbine blade row, the third low-pressure turbine blade row, and the fourth lowpressure turbine blade row.
[0008] With the above configuration (1), 5 since a four-flow exhaust type is adopted where the high-pressure turbine blade row, the intermediate-pressure turbine blade row, and the first to fourth low-pressure turbine blade rows are disposed on the one rotor shaft, and the steam having passed through the intermediate-pressure turbine blade row is divided to flow into each of the first to fourth low-pressure turbine
blade rows, it is possible to have performance comparable to that of the abovedescribed conventional high-performance steam turbine of a four-casing
configuration (that is, the four-flow exhaust type steam turbine including the highpressure turbine blade row, the intermediate-pressure turbine blade row, and two sets of double-flow exhaust type low-pressure turbine blade rows). Moreover, in the above configuration (1), since the pair of low-pressure turbine blade rows (the first low-pressure turbine blade row and the second low-pressure turbine blade row) are disposed on the both sides of the intermediate-pressure turbine blade row,
respectively, it is possible to accommodate these turbine blade rows in one casing, and since the pair of low-pressure turbine blade rows (the third low-pressure turbine blade row and the fourth low-pressure turbine blade row) are disposed on the both sides of the high-pressure turbine blade row, respectively, it is possible to
accommodate these turbine blade rows in one casing. Thus, it is possible to
implement the steam turbine facility of a two-casing configuration.
That is, with the above configuration (1), it is possible to reduce an
installation area by reducing the number of casings than ever before, while
implementing performance corresponding to that of the conventional high-
performance steam turbine having four casings. Therefore, it is possible to
implement the steam turbine facility capable of reducing a facility cost, while having high performance.
[0009] (2) In some embodiments, in the above configuration (1), the steam turbine facility further includes a first pair of radial bearings 5 and a second pair of radial bearings for rotatably supporting the rotor shaft. The intermediate-pressure
turbine blade row, the first low-pressure turbine blade row, and the second lowpressure turbine blade row are disposed on the rotor shaft in a bearing span of the first pair of radial bearings, and the high-pressure turbine blade row, the third low pressure turbine blade row, and the fourth low-pressure turbine blade row are disposed on the rotor shaft in a bearing span of the second pair of radial bearings.
[0010] With the above configuration (2), since the intermediate-pressure turbine blade row and the pair of low-pressure turbine blade rows (the first low-pressure turbine blade row and the second low-pressure turbine blade row) are disposed in the bearing span of the pair of radial bearings, respectively, it is possible to accommodate these turbine blade rows in the single casing, and since the highpressure turbine blade row and the pair of low-pressure turbine blade rows (the third low-pressure turbine blade row and the fourth low-pressure turbine blade row) are
disposed in the bearing span of the pair of radial bearings, respectively, it is possible to accommodate these turbine blade rows in the single casing. Thus, it is possible to implement the steam turbine facility of the two-casing configuration, and to reduce the installation area as compared to the conventional high-performance steam turbine.
[0011] (3) In some embodiments, in the above configuration (1) or (2), the steam turbine facility further includes a first casing for accommodating the intermediatepressure
turbine blade row, the first low-pressure turbine blade row, and the second low-pressure turbine blade row, and a second casing for accommodating the highpressure turbine blade row, the third low-pressure turbine blade row, and the fourth low-pressure turbine blade row.
[0012] With the above configuration (3), since the intermediate-pressure turbine blade row and the pair of low-pressure 5 turbine blade rows (the first low-pressure turbine blade row and the second low-pressure turbine blade row) are accommodated in the first casing, and the high-pressure turbine blade row and the pair of low-pressure turbine blade rows (the third low-pressure turbine blade row and the fourth low-pressure turbine blade row) are accommodated in the second casing, it is possible to reduce the installation area as compared to the conventional
high-performance steam turbine, with the steam turbine facility having the twocasing
configuration.
[0013] (4) In some embodiments, in the above configuration (3), the steam turbine facility further includes a thrust bearing for rotatably supporting the rotor shaft. The thrust bearing is disposed between the first casing and the second casing.
[0014] With the above configuration (4), since the thrust bearing is disposed
between the casings (that is, between the first casing and the second casing), it is possible to reduce an influence by thermal expansion of the casings and components accommodated in the casings, respectively, on both sides of the thrust bearing in the axial direction.
[0015] (5) In some embodiments, in any one of the above configurations (1) to (4),
the first low-pressure turbine blade row is disposed downstream of the intermediatepressure
turbine blade row in a steam flow direction in the intermediate-pressure
turbine blade row, and the steam turbine facility includes a branched channel for introducing a part of a steam flow from the intermediate-pressure turbine blade row
toward the first low-pressure turbine blade row to the second low-pressure turbine blade row, the third low-pressure turbine blade row, and the fourth low-pressure turbine blade row.
[0016] With the above configuration (5), since the part of the steam flow from the intermediate-pressure turbine blade row toward the first low-pressure turbine blade row is introduced to the second low-5 pressure turbine blade row, the third lowpressure turbine blade row, and the fourth low-pressure turbine blade row via the branched channel, it is possible to implement the high-performance steam turbine facility of the four-flow exhaust type, while achieving the two-casing configuration capable of reducing the installation area.
[0017] (6) In some embodiments, in the above configuration (5), the steam turbine facility includes a first casing for accommodating the intermediate-pressure turbine blade row, the first low-pressure turbine blade row, and the second low-pressure turbine blade row, and a second casing for accommodating the high-pressure turbine blade row, the third low-pressure turbine blade row, and the fourth low-pressure
turbine blade row. The branched channel includes a first inner channel disposed so as to cause an inlet side of the first low-pressure turbine blade row and an inlet side of the second low-pressure turbine blade row to communicate with each other,
in the first casing, a second inner channel disposed so as to cause an inlet side of the third low-pressure turbine blade row and an inlet side of the fourth low-pressure turbine blade row to communicate with each other, in the second casing, and a connection pipe having an end connected to the first inner channel in the first casing
and another end connected to the second inner channel in the second casing.
[0018] With the above configuration (6), since a portion of the branched channel,
which causes the pair of low-pressure turbine blade rows accommodated in the
same casing to communicate with each other, is disposed as the inner channel inside the casing, and a portion of the branched channel, which causes the first/second low-pressure turbine blade rows and the third/fourth low-pressure turbine blade rows accommodated in the different casings to communicate with each other, is formed by the connection pipe, it is possible to implement the four-flow exhaust type steam turbine facility, while enabling downsizing of the steam turbine facility.
[0019] (7) In some embodiments, in the above 5 configuration (5) or (6), the steam turbine facility includes a first casing for accommodating the intermediate-pressure
turbine blade row, the first low-pressure turbine blade row, and the second lowpressure turbine blade row. The first casing includes an inner casing for
accommodating the intermediate-pressure turbine blade row, and an outer casingfor accommodating the inner casing, and at least a part of the first low-pressure turbine blade row and the second low-pressure turbine blade row, and the branched channel is formed at least partially by an outer surface of the inner casing and an inner surface of the outer casing.
[0020] With the above configuration (7), since the branched channel is formed at least partially by using the outer casing and the inner casing positioned on the inner side of the outer casing, it is possible to implement the steam turbine facility capable
of reducing the installation area and having high performance, by the simple
configuration.
[0021] (8) In some embodiments, in the above configuration (5) or (6), the steam turbine facility includes a first casing for accommodating the intermediate-pressure
turbine blade row, the first low-pressure turbine blade row, and the second lowpressure turbine blade row. The first casing includes an inner casing for
accommodating the intermediate-pressure turbine blade row, and an outer casing
for accommodating the inner casing, and at least a part of the first low-pressure turbine blade row and the second low-pressure turbine blade row, and the branched channel is formed at least partially by a pipe passing outside the outer casing.
[0022] With the above configuration (8), since the branched channel is formed at least partially by the pipe passing outside the outer casing, it is possible to implement the steam turbine facility capable of reducing the installation area and having high performance, by the simple configuration.
[0023] (9) In some embodiments, in any one of 5 the above configurations (5) to (8), the steam turbine facility further includes a steam introduction path connected to the branched channel, for introducing steam having a pressure lower than a pressure of steam in an inlet of the first low-pressure turbine blade row.
[0024] In the above configuration (9), since the above-described steam
introduction path connected to the branched channel is provided, the steam with the lower pressure introduced from the steam introduction path to the branched channel is introduced to the third and fourth low-pressure turbine blade rows via the branched channel, in addition to a part of steam flowing into the inlet of the first low-pressure turbine blade row (for example, exhaust air from the intermediate1pressure turbine blade row, or steam from a low-pressure drum or a low-pressure
evaporator of a boiler). Therefore, with the above configuration (9), it is possible to improve output power of the steam turbine facility.
[0025] (10) In some embodiments, in any one of the above configurations (1) to
(9), the steam turbine facility is configured such that steam flowing through the high-pressure turbine blade row and steam flowing through the intermediatepressure
turbine blade row flow in opposite directions to each other in an axial
direction, the steam turbine facility is configured such that steam flowing through the first low-pressure turbine blade row and steam flowing through the second lowpressure turbine blade row flow in opposite directions to each other in the axial direction, and the steam turbine facility is configured such that steam flowing through the third low-pressure turbine blade row and steam flowing through the fourth low-pressure turbine blade row flow in opposite directions to each other in
the axial direction.
[0026] With the above configuration (10), since the respective turbine blade rows
are disposed such that the steam flowing through the high-pressure turbine blade
row and the steam flowing through 5 the intermediate-pressure turbine blade row
flow in the opposite directions to each other in the axial direction, and the steams
flowing through the first/second pair of low-pressure turbine blade rows,
respectively, flow in the opposite directions to each other in the axial direction, it is
possible to balance a thrust load acting on the rotor shaft.
10 [0027] (11) In some embodiments, in any one of the above configurations (1) to
(10), the steam turbine facility further includes an exhaust chamber for discharging
steam from the first low-pressure turbine blade row and from the second lowpressure
turbine blade row toward a condenser. The exhaust chamber has an
exhaust chamber outlet disposed on a lateral side thereof.
15 [0028] With the above configuration (11), the steam having passed through the
first/second low-pressure turbine blade rows is laterally exhausted toward the
condenser via the exhaust chamber outlet disposed on the lateral side of the exhaust
chamber. That is, since the condenser can be disposed on the lateral side of the
exhaust chamber, it is possible to reduce the size of the steam turbine facility in the
20 height direction, as compared with a case in which the condenser is positioned
below the exhaust chamber. Therefore, it is possible to reduce the facility cost of
the steam turbine facility more effectively.
[0029] (12) In some embodiments, in any one of the above configurations (1) to
(11), the steam turbine facility further includes a condenser for condensing steam
25 from the first low-pressure turbine blade row and from the second low-pressure
turbine blade row.
10
[0030] (13) A combined cycle plant according to at least one embodiment of the
present invention includes a gas turbine facility, a boiler for generating steam by
heat of a discharged gas from the gas turbine facility, and the steam turbine facility
according to any one of the above configurations (1) to (12). The steam turbine
facility is configured to be driven by 5 the steam generated by the boiler.
[0031] With the above configuration (13), since a four-flow exhaust type is
adopted where the high-pressure turbine blade row, the intermediate-pressure
turbine blade row, and the first to fourth low-pressure turbine blade rows are
disposed on the one rotor shaft, and the steam having passed through the
10 intermediate-pressure turbine blade row is divided to flow into each of the first to
fourth low-pressure turbine blade rows, it is possible to have performance
comparable to that of the above-described conventional high-performance steam
turbine of a four-casing configuration (that is, the four-flow exhaust type steam
turbine including the high-pressure turbine blade row, the intermediate-pressure
15 turbine blade row, and two sets of double-flow exhaust type low-pressure turbine
blade rows). Moreover, in the above configuration (13), since the pair of lowpressure
turbine blade rows (the first low-pressure turbine blade row and the second
low-pressure turbine blade row) are disposed on the both sides of the intermediatepressure
turbine blade row, respectively, it is possible to accommodate these turbine
20 blade rows in one casing, and since the pair of low-pressure turbine blade rows (the
third low-pressure turbine blade row and the fourth low-pressure turbine blade row)
are disposed on the both sides of the high-pressure turbine blade row, respectively,
it is possible to accommodate these turbine blade rows in one casing. Thus, it is
possible to implement the steam turbine facility of a two-casing configuration.
25 That is, with the above configuration (13), it is possible to reduce an
installation area by reducing the number of casings than ever before, while
11
implementing performance corresponding to that of the conventional highperformance
steam turbine having four casings. Therefore, it is possible to
implement the combined cycle plant including the steam turbine facility capable of
reducing the facility cost, while having high performance.
5
Advantageous Effects
[0032] According to at least one embodiment of the present invention, a steam
turbine facility capable of reducing a facility cost while having high performance
and a combined cycle plant including the same are provided.
10
BRIEF DESCRIPTION OF DRAWINGS
[0033] FIG. 1 is a schematic configuration diagram of a combined cycle plant
according to an embodiment.
FIG. 2 is a schematic cross-sectional view of a steam turbine facility
according to an 15 embodiment, taken along its axial direction.
FIG. 3 is a cross-sectional view taken along line A-A (or a cross-sectional
view taken along line A’-A’) in FIG. 2.
DETAILED DESCRIPTION
20 [0034] Some embodiments of the present invention will be described below with
reference to the accompanying drawings. It is intended, however, that unless
particularly identified, dimensions, materials, shapes, relative positions and the like
of components described in the embodiments or shown in the drawings shall be
interpreted as illustrative only and not intended to limit the scope of the present
25 invention.
[0035] First, a combined cycle plant to which a steam turbine facility according
12
to some embodiments is applied will be described with reference to FIG. 1.
FIG. 1 is a schematic configuration diagram of the combined cycle plant
according to an embodiment. As shown in the diagram, a combined cycle plant 1
is a gas turbine combined cycle (GTCC) plant including a gas turbine facility 2, a
heat recovery steam generator (HRSG) 6 (boiler), 5 and a steam turbine facility 4.
[0036] The gas turbine facility 2 shown in FIG. 1 includes a compressor 10, a
combustor 12, and a turbine 14. The compressor 10 is configured to compress air
to produce compressed air. The combustor 12 is configured to generate a
combustion gas by a combustion reaction between the compressed air from the
10 compressor 10 and a fuel (for example, a natural gas or the like). The turbine 14
is configured to be rotary driven by the combustion gas from the combustor 12.
The turbine 14 is connected to a generator 18 via a rotational shaft 16. The
generator 18 is driven by rotational energy of the turbine 14 to generate electric
power. The combustion gas having finished work in the turbine 14 is discharged
15 from the turbine 14 as a discharged gas.
[0037] The heat recovery steam generator 6 is configured to generate steam by
heat of the discharged gas from the gas turbine facility 2.
The heat recovery steam generator 6 includes a duct (not shown) to which
the discharged gas from the gas turbine facility 2 is introduced and a heat exchanger
20 (not shown) disposed so as to pass inside the duct. Into the heat exchanger,
condensate water from a condenser 34 of the steam turbine facility 4 to be described
later is introduced. In the heat exchanger, steam is generated by heat exchange
between the condensate water and the discharged gas flowing through the abovedescribed
duct.
25 Note that the discharged gas having flown through the duct of the heat
recovery steam generator 6 and passed through the heat exchanger may be
13
discharged from a stack (not shown).
[0038] The steam turbine facility 4 shown in FIG. 1 includes a plurality of turbine
blade rows 22, 24, 26A to 26D and is configured to be driven by the steam from the
heat recovery steam generator 6.
The steam generated by the heat recovery 5 steam generator 6 is introduced
to the steam turbine facility 4. The steam turbine facility 4 is rotary driven by the
steam. Moreover, the steam turbine facility 4 is connected to a generator 32 via a
rotor shaft 28. The generator 32 is rotary driven by the steam turbine facility 4 to
generate electric power.
10 [0039] The steam turbine facility 4 according to some embodiments will be
described below in more detail.
FIG. 2 is a schematic cross-sectional view of the steam turbine facility 4
according to an embodiment, taken along its axial direction. Note that arrows in
FIG. 2 each indicate the direction of a steam flow in the steam turbine facility 4.
15 As shown in FIGs. 1 and 2, the steam turbine facility 4 includes the rotor
shaft 28, a first pair of radial bearings 30A, 30B, a second pair of radial bearings
31A, 31B, and a thrust bearing 68 for rotatably supporting the rotor shaft 28, the
turbine blade rows 22, 24, 26A to 26D disposed on the rotor shaft 28, and a first
casing 80 and a second casing 82.
20 [0040] The above-described turbine blade rows include the high-pressure turbine
blade row 22 where high-pressure steam from a boiler (such as the above-described
heat recovery steam generator) is introduced, the intermediate-pressure turbine
blade row 24 where steam of a lower pressure (intermediate-pressure steam) is
introduced, and the first low-pressure turbine blade row 26A to the fourth low25
pressure turbine blade row 26D where steam of a further lower pressure (lowpressure
steam) is introduced.
14
Note that in the present specification, the “low-pressure turbine blade row”
means a turbine blade row disposed downstream of a branched channel 62 to be
described later.
[0041] The first low-pressure turbine blade row 26A and the second low-pressure
turbine blade row 26B are disposed 5 on both sides of the intermediate-pressure
turbine blade row 24 in the axial direction, respectively. The intermediatepressure
turbine blade row 24, the first low-pressure turbine blade row 26A, and the
second low-pressure turbine blade row 26B are disposed on a first shaft part 27 of
the rotor shaft 28, in a bearing span of the first pair of radial bearings 30A, 30B.
10 Then, these turbine blade rows (the intermediate-pressure turbine blade row 24, the
first low-pressure turbine blade row 26A, and the second low-pressure turbine blade
row 26B) are accommodated in the first casing 80.
[0042] Moreover, the third low-pressure turbine blade row 26C and the fourth
low-pressure turbine blade row 26D are disposed on both sides of the high-pressure
15 turbine blade row 22 in the axial direction, respectively. The high-pressure turbine
blade row 22, the third low-pressure turbine blade row 26C, and the fourth lowpressure
turbine blade row 26D are disposed on a second shaft part 29 of the rotor
shaft 28, in a bearing span of the second pair of radial bearings 31A, 31B. Then,
these turbine blade rows (the high-pressure turbine blade row 22, the third low20
pressure turbine blade row 26C, and the fourth low-pressure turbine blade row 26D)
are accommodated in the second casing 82.
[0043] Note that any other radial bearing is not disposed in the bearing span of
each pair of radial bearings, in the axial direction. That is, any other radial bearing
is neither disposed between the radial bearing 30A and the radial bearing 30B, nor
25 between the radial bearing 31A and the radial bearing 31B.
[0044] The first shaft part 27 and the second shaft part 29 are connected via a
15
coupling 70 (see FIG. 2) disposed between the first pair of radial bearings 30A, 30B
and the second pair of radial bearings 31A, 31B.
The “rotor shaft” in the present specification may thus include the plurality
of shaft parts connected via the coupling 70.
[0045] The thrust bearing 68 is disposed between 5 the first casing 80 and the
second casing 82 in the axial direction. Note that in the exemplary embodiment
shown in FIG. 2, the thrust bearing 68 is disposed between the coupling 70 and the
first pair of radial bearings 30A, 30B. However, in another embodiment, the thrust
bearing 68 may be disposed between the coupling 70 and the second pair of radial
10 bearings 31A, 31B, or may be disposed between the radial bearing 30A and the
radial bearing 30B or between the radial bearing 31A and the radial bearing 31B.
[0046] As shown in FIG. 2, the first casing 80 for accommodating the
intermediate-pressure turbine blade row 24 and the first/second low-pressure
turbine blade rows 26A, 26B includes an outer casing 20 and an inner casing 36
15 disposed inside the outer casing 20. The intermediate-pressure turbine blade row
24 is accommodated in the inner casing 36, and the inner casing 36 and the
first/second low-pressure turbine blade rows 26A, 26B are accommodated in the
outer casing 20.
[0047] Moreover, the second casing for accommodating the high-pressure turbine
20 blade row 22 and the third/fourth low-pressure turbine blade rows 26C, 26D
includes an outer casing 21 and an inner casing 37 disposed inside the outer casing
21. The high-pressure turbine blade row 22 is accommodated in the inner casing
37, and the inner casing 37 and the third/fourth low-pressure turbine blade rows
26C, 26D are accommodated in the outer casing 21.
25 [0048] The outer casing 20 of the first casing 80 includes a bearing cone part 84
disposed radially outside the radial bearings 30A, 30B. Moreover, the outer casing
16
21 of the second casing 82 includes a bearing cone part 86 disposed radially outside
the radial bearings 31A, 31B.
[0049] Each of the turbine blade rows 22, 24, 26A to 26D includes a plurality of
stator vanes 7 and rotor blades 8. The plurality of stator vanes 7 and rotor blades
8 are arranged in the circumferential direction 5 to form rows, respectively. The
rows of the stator vanes 7 and the rows of the rotor blades 8 are arranged alternately
in the axial direction.
Note that each of the turbine blade rows 22, 24, 26A to 26D may include a
plurality of sets of rows of the stator vanes 7 and rows of the rotor blades 8.
10 [0050] The stator vanes 7 of each of the turbine blade rows 22, 24, 26A to 26D
are accommodated in the inner casings 36, 37 or the outer casings 20, 21 serving as
stationary members, respectively.
In the exemplary embodiment shown in FIG. 2, the stator vanes 7 of the
high-pressure turbine blade row 22 and the intermediate-pressure turbine blade row
15 24 are accommodated the inner casings 36, 37, respectively. Moreover, the lowpressure
turbine blade rows 26A to 26D are accommodated in the outer casings 20,
21, respectively.
[0051] Furthermore, the rotor blades 8 of the respective turbine blade rows 22, 24,
26A to 26D are mounted on the rotor shaft 28 and rotate with the rotor shaft 28.
20 [0052] The inlets of the high-pressure turbine blade row 22 and the intermediatepressure
turbine blade row 24 are connected to a high-pressure inlet pipe 38 and an
intermediate-pressure inlet pipe 42, respectively. Moreover, a space (steam
channel) between the inlet and outlet of the intermediate-pressure turbine blade row
24 is connected to a low-pressure inlet pipe 44, in the axial direction. Moreover,
25 the outlet of the high-pressure turbine blade row 22 is connected to a high-pressure
outlet pipe 40.
17
[0053] High-pressure steam, intermediate-pressure steam, and low-pressure steam
are introduced to the high-pressure turbine blade row 22, the intermediate-pressure
turbine blade row 24, and the space (steam channel) between the inlet and outlet of
the intermediate-pressure turbine blade row 24 via the high-pressure inlet pipe 38,
the intermediate-pressure inlet pipe 42, and 5 the low-pressure inlet pipe 44,
respectively.
[0054] The steams introduced to the respective turbine blade rows via the highpressure
inlet pipe 38, the intermediate-pressure inlet pipe 42, and the low-pressure
inlet pipe 44 may be the steams generated by the boiler described above.
10 Moreover, the steam having passed through the high-pressure turbine blade row 22
and discharged from the high-pressure outlet pipe 40 may be re-heated by a reheater
or the like, and then may be introduced to the intermediate-pressure turbine
blade row 24 via the intermediate-pressure inlet pipe 42.
[0055] As shown in FIG. 2, the first low-pressure turbine blade row 26A is
15 disposed downstream of the intermediate-pressure turbine blade row 24 in a steam
flow direction in the intermediate-pressure turbine blade row 24. That is, steam
having passed through the intermediate-pressure turbine blade row 24 can flow into
the inlet of the first low-pressure turbine blade row 26A.
[0056] Then, the steam turbine facility 4 includes the branched channel 62 for
20 introducing a part of a steam flow from the intermediate-pressure turbine blade row
24 toward the first low-pressure turbine blade row 26A to the second low-pressure
turbine blade row 26B, the third low-pressure turbine blade row 26C, and the fourth
low-pressure turbine blade row 26D. That is, in the steam turbine facility 4, the
steam having passed through the intermediate-pressure turbine blade row 24 is
25 divided to flow into the first low-pressure turbine blade row 26A, the second lowpressure
turbine blade row 26B, the third low-pressure turbine blade row 26C, and
18
the fourth low-pressure turbine blade row 26D, via the branched channel 62.
[0057] In the exemplary embodiment shown in FIG. 2, the branched channel 62
includes a first inner channel 64 disposed inside the first casing 80, a second inner
channel 66 disposed inside the second casing 82, and a connection pipe 65 disposed
between the first inner channel 64 and 5 the second inner channel 66.
The first inner channel 64 is disposed so as to cause an inlet side of the first
low-pressure turbine blade row 26A and an inlet side of the second low-pressure
turbine blade row 26B to communicate with each other, in the first casing 80.
The second inner channel 66 is disposed so as to cause an inlet side of the
10 third low-pressure turbine blade row 26C and an inlet side of the fourth lowpressure
turbine blade row 26D to communicate with each other, in the second
casing 82.
The connection pipe 65 has an end connected to the first inner channel 64
in the first casing 80 and another end connected to the second inner channel 66 in
15 the second casing 82.
[0058] In the steam turbine facility 4 including the above-described branched
channel 62, a part of the steam having passed through the intermediate-pressure
turbine blade row 24 flows into the first low-pressure turbine blade row 26A, and a
part of the rest of the steam heads for the first inner channel 64. Then, a part of
20 the steam having flown into the first inner channel 64 flows into the second lowpressure
turbine blade row 26B, and a part of the rest of the steam heads for the
second inner channel 66 of the second casing 82 through the connection pipe 65.
A part of the steam having flown into the second inner channel 66 flows into the
third low-pressure turbine blade row 26C, and the rest of the steam flows into the
25 fourth low-pressure turbine blade row 26D.
[0059] Note that the first to fourth low-pressure turbine blade rows 26A to 26D
19
may have the same number of stages (number of sets of rows of the stator vanes 7
and rows of the rotor blades 8) of the rows of the stator vanes 7 and rows of the
rotor blades 8. FIG. 2 is a schematic view, and in the exemplary embodiment
shown in FIG. 2, the number of stages of each of the first to fourth low-pressure
5 turbine blade rows is one.
[0060] A seal part for suppressing fluid leakage may be disposed between the rotor
shaft 28 and the inner casing 36, 37 in the radial direction. For example, in the
exemplary embodiment shown in FIG. 2, a seal part 60 for suppressing fluid leakage
between the intermediate-pressure turbine blade row 24 and the second low10
pressure turbine blade row 26B is disposed in the first casing 80. Moreover, seal
parts 61, 63 for suppressing fluid leakages between the high-pressure turbine blade
row 22, and the third low-pressure turbine blade row 26C and the fourth lowpressure
turbine blade row 26D, respectively, are disposed in the second casing 82.
[0061] In such a steam turbine facility 4, if steam is introduced to each of the
15 turbine blade rows 22, 24, 26A to 26D, the steam expands and are increased in speed
when passing through the stator vanes 7, and the steam thus increased in speed
performs work on the rotor blades 8 and rotates the rotor shaft 28.
[0062] The steam turbine facility 4 also includes a pair of exhaust chambers 50
and a pair of exhaust chambers 52. The pair of exhaust chambers 50 are disposed
20 to be positioned downstream of the low-pressure turbine blade rows 26A, 26B,
respectively. Moreover, the pair of exhaust chambers 52 are disposed to be
positioned downstream of the low-pressure turbine blade rows 26C, 26D,
respectively.
[0063] The steams having passed through the low-pressure turbine blade rows
25 26A, 26B are guided by a flow guide 54 to flow into the exhaust chambers 50, pass
inside the exhaust chambers 50, respectively, and are discharged via an exhaust
20
chamber outlet 51 (see FIG. 3) disposed on each of the exhaust chambers 50.
Moreover, the steams having passed through the low-pressure turbine
blade rows 26C, 26D are guided by a flow guide 55 to flow into the exhaust
chambers 52, pass inside the exhaust chambers 52, respectively, and are discharged
via an exhaust chamber outlet 53 (see FIG. 5 3) disposed on each of the exhaust
chambers 52.
[0064] The condenser 34 (see FIG. 1) is disposed downstream of the exhaust
chamber outlet 51, 53. The steam discharged from the exhaust chamber outlet 51,
53 flows into the condenser 34. In the condenser 34, the steam is cooled by heat
10 exchange with cooling water to be condensed, generating condensed water
(condensate water).
[0065] In some embodiments, the exhaust chamber outlets 51, 53 may be disposed
on the lower sides of the exhaust chambers 50, 52, respectively, and the condenser
34 may be disposed below the exhaust chamber 50, 52. Alternatively, in some
15 embodiments, the exhaust chamber outlets 51, 53 may be disposed on the lateral
sides of the exhaust chambers 50, 52, respectively, and the condenser 34 may be
disposed on the lateral side of the exhaust chamber 50, 52.
[0066] The steam turbine facility 4 according to the above-described embodiment
is the four-flow exhaust type steam turbine facility 4, where the high-pressure
20 turbine blade row 22, the intermediate-pressure turbine blade row 24, and the first
to fourth low-pressure turbine blade rows 26A to 26D are disposed on the one rotor
shaft 28, and the steam having passed through the intermediate-pressure turbine
blade row 24 is divided to flow into each of the first to fourth turbine blade rows
26A to 26D. Thus, it is possible to have performance comparable to that of the
25 conventional high-performance steam turbine of a four-casing configuration (that
is, the four-flow exhaust type steam turbine including the high-pressure turbine
21
blade row, the intermediate-pressure turbine blade row, and two sets of double-flow
exhaust type low-pressure turbine blade rows). Moreover, in the steam turbine
facility 4 according to the above-described embodiment, since the pair of lowpressure
turbine blade rows (the first low-pressure turbine blade row 26A and the
second low-pressure turbine blade row 26B) are 5 disposed on the both sides of the
intermediate-pressure turbine blade row 24, respectively, it is possible to
accommodate these turbine blade rows in one casing (first casing 80), and since the
pair of low-pressure turbine blade rows (the third low-pressure turbine blade row
26C and the fourth low-pressure turbine blade row 26D) are disposed on the both
10 sides of the high-pressure turbine blade row 22, respectively, it is possible to
accommodate these turbine blade rows in one casing (second casing 82). Thus, it
is possible to implement the steam turbine facility 4 of a two-casing configuration.
That is, according to the above-described steam turbine facility 4, it is
possible to reduce an installation area by reducing the number of casings than ever
15 before, while implementing performance corresponding to that of the conventional
high-performance steam turbine having four casings. Therefore, it is possible to
implement the steam turbine facility capable of reducing a facility cost, while
having high performance.
[0067] Moreover, in the steam turbine facility 4 according to the above-described
20 embodiment, since the intermediate-pressure turbine blade row 24 and the pair of
low-pressure turbine blade rows (the first low-pressure turbine blade row 26A and
the second low-pressure turbine blade row 26B) are disposed in the bearing span of
the pair of radial bearings 30A, 30B, respectively, it is possible to accommodate
these turbine blade rows in the single casing (first casing 80), and since the high25
pressure turbine blade row 22 and the pair of low-pressure turbine blade rows (the
third low-pressure turbine blade row 26C and the fourth low-pressure turbine blade
22
row 26D) are disposed in the bearing span of the pair of radial bearings 31A, 31B,
respectively, it is possible to accommodate these turbine blade rows in the single
casing (second casing 82). Thus, it is possible to implement the steam turbine
facility 4 of the two-casing configuration, and to reduce the installation area as
compared to the conventional 5 high-performance steam turbine.
[0068] Moreover, in the steam turbine facility 4 according to the above-described
embodiment, since the thrust bearing 68 for rotatably supporting the rotor shaft 28
is disposed between the casings (that is, between the first casing 80 and the second
casing 82), it is possible to dispose the origin of thermal expansion in the axial
10 direction of the rotor shaft 28 between the casings. Thus, it is possible to reduce
an influence by the thermal expansion of the first casing 80, the second casing 82,
and components accommodated in these casings, respectively, on both sides of the
thrust bearing 68 in the axial direction.
[0069] Moreover, in the steam turbine facility 4 according to the above-described
15 embodiment, since the part of the steam flow from the intermediate-pressure turbine
blade row 24 toward the first low-pressure turbine blade row 26A is introduced to
the second low-pressure turbine blade row 26B, the third low-pressure turbine blade
row 26C, and the fourth low-pressure turbine blade row 26D via the branched
channel 62, it is possible to implement the high-performance steam turbine facility
20 4 of the four-flow exhaust type, while achieving the two-casing configuration
capable of reducing the installation area.
[0070] In the exemplary embodiment shown in FIG. 2, the first inner channel 64
of the branched channel 62 is an annular channel formed by an outer circumferential
surface 36a of the inner casing 36 and an inner circumferential surface 20a of the
25 outer casing 20 of the first casing 80. Moreover, the second inner channel 66 of
the branched channel 62 is an annular channel formed by an outer circumferential
23
surface 37a of the inner casing 37 and an inner circumferential surface 21a of the
outer casing 21 of the second casing 82.
[0071] Thus at least partially forming the branched channel 62 by using the outer
casings 20, 21 and the inner casings 36, 37 positioned on the inner sides of the outer
casings 20, 21, respectively, it is possible to implement 5 the steam turbine facility 4
capable of reducing the installation area and having high performance, by the
simple configuration.
In addition, since the first inner channel 64 and the second inner channel
66 of the branched channel 62 are the annular channels, respectively, it is easy to
10 ensure a large channel area of the branched channel 62.
[0072] The outer casings 20, 21 may be produced from sheet metal. Moreover,
the inner casings 36, 37 may each be produced as a casting.
The steam flowing through the branched channel 62 disposed downstream
of the intermediate-pressure turbine blade row 24 has a relatively low temperature.
15 A difference between a pressure of this steam having a relatively low pressure and
a pressure (typically, the atmospheric pressure) outside the outer casings 20, 21 is
relatively small, making it possible to have a required strength even if the outer
casings 20, 21 are produced from the sheet metal. Thus, producing the outer
casings 20, 21 from the sheet metal, it is possible to implement the above-described
20 steam turbine facility 4 at a relatively low cost, while having the strength required
as the steam turbine facility 4.
[0073] In the embodiment shown in FIG. 2, guide members 48 for guiding the
flow of steam in the first inner channel 64 are disposed radially inner side of the
outer casing 20 and radially outer side of the inner casing 36. The guide members
25 48 are disposed obliquely with respect to the axial direction of the steam turbine
facility 4 to be gradually distanced from a center axis O of the rotor shaft 28 toward
24
a center position between the pair of low-pressure turbine blade rows 26A, 26B, in
the axial direction.
Moreover, in the embodiment shown in FIG. 2, guide members 49 for
guiding the flow of steam in the second inner channel 66 are disposed radially inner
side of the outer casing 21 and radially outer side 5 of the inner casing 37. The guide
members 49 are disposed obliquely with respect to the axial direction of the steam
turbine facility 4 to be gradually distanced from the center axis O of the rotor shaft
28 toward a center position between the pair of low-pressure turbine blade rows
26C, 26D, in the axial direction.
10 [0074] Moreover, in the embodiment shown in FIG. 2, the outer circumferential
surfaces 36a, 37a of the inner casings 36, 37 each have a smooth shape including a
convex curve protruding radially outward, in a cross-section along the axial
direction.
[0075] Disposing the above-described guide members 48, 49 or forming each of
15 the outer circumferential surfaces 36a, 37a of the inner casings 36, 37 into the
smooth shape as described above, it is possible to reduce turbulence of a steam flow
in the branched channel 62, and thus to reduce a fluid loss.
[0076] An insulator may be disposed on the member forming the branched
channel 62 or the surface of a member disposed in the branched channel 62. For
20 example, in the embodiment shown in FIG. 2, insulators 56, 57 are disposed on the
outer circumferential surfaces 36a, 37a of the inner casings 36, 37 forming the first
inner channel 64 and the second inner channel 66 (branched channel 62),
respectively. Moreover, although not illustrated in particular, an insulator may be
disposed in a portion of the high-pressure inlet pipe 38 or the high-pressure outlet
25 pipe 40 passing through the second inner channel 66 (branched channel 62). In
addition, as shown in FIG. 2, insulators 58, 59 may be disposed on the inner
25
circumferential surfaces 20a, 21a of the outer casings 20, 21 forming the branched
channel 62 and the surfaces of the guide members 48, 49, respectively.
[0077] Disposing the above-described insulators, it is possible to suppress heat
dissipation from the inner casings 36, 37, the high-pressure inlet pipe 38 or the highpressure
outlet pipe 40, and the like where steam 5 of a relatively high temperature
flows to the first inner channel 64 and the second inner channel 66 (branched
channel 62) where steam of relatively low temperature flows. Thus, it is possible
to suppress an efficiency decrease of the steam turbine facility 4 caused by such
heat dissipation.
10 [0078] In some embodiments, the branched channel 62 may at least partially be
formed by a pipe passing outside the outer casing 20 (first casing 80) or the outer
casing 21 (second casing 82).
[0079] Although not illustrated in particular, for example, in an embodiment, the
branched channel 62 includes a first pipe, a second pipe, and a connection pipe
15 disposed between the first pipe and the second pipe. The first pipe passes outside
the first casing 80, and causes the inlet side of the first low-pressure turbine blade
row 26A and the inlet side of the second low-pressure turbine blade row 26B to
communicate with each other. The second pipe passes outside the second casing
82, and causes the inlet side of the third low-pressure turbine blade row 26C and
20 the inlet side of the fourth low-pressure turbine blade row 26D to communicate with
each other. The connection pipe having an end connected to the above-described
first pipe and another end connected to the above-described second pipe.
[0080] Thus at least partially forming the branched channel 62 by the pipes
passing outside the outer casings 20, 21, respectively, it is possible to implement
25 the steam turbine facility 4 capable of reducing the installation area and having high
performance, by the simple configuration.
26
[0081] In the exemplary embodiment shown in FIG. 2, the connection pipe 65 of
the branched channel 62 is connected to a steam introduction path 74. The steam
introduction path 74 is configured to introduce steam having a pressure lower than
a pressure of steam in an inlet of the first low-pressure turbine blade row 26A to the
connection 5 pipe 65 (branched channel 62).
[0082] Thus introducing the steam having the pressure lower than the pressure of
the steam in the inlet of the first low-pressure turbine blade row 26A to the
connection pipe 65 (branched channel 62) via the steam introduction path 74, the
steam with the lower pressure introduced from the steam introduction path 74 to the
10 branched channel 62 is introduced to the third low-pressure turbine blade row 26C
and the fourth low-pressure turbine blade row 26D, in addition to a part of steam
flowing into the inlet of the first low-pressure turbine blade row 26A. Therefore,
it is possible to improve output power of the steam turbine facility 4.
[0083] Note that in the embodiment shown in FIG. 2, since the connection pipe
15 65 of the branched channel 62 passes outside the first casing 80 and the second
casing 82, it is possible to easily connect the steam introduction path 74 to the
connection pipe 65.
[0084] Moreover, in the exemplary embodiment shown in FIG. 2, the highpressure
turbine blade row 22 and the intermediate-pressure turbine blade row 24
20 are disposed such that the steam flowing through the high-pressure turbine blade
row 22 and the steam flowing through the intermediate-pressure turbine blade row
24 flow in opposite directions to each other in the axial direction. Moreover, the
first low-pressure turbine blade row 26A and the second low-pressure turbine blade
row 26B are disposed such that the steam flowing through the first low-pressure
25 turbine blade row 26A and the steam flowing through the second low-pressure
turbine blade row 26B flow in opposite directions to each other in the axial direction.
27
Furthermore, the third low-pressure turbine blade row 26C and the fourth lowpressure
turbine blade row 26D are disposed such that the steam flowing through
the third low-pressure turbine blade row 26C and the steam flowing through the
fourth low-pressure turbine blade row 26D flow in opposite directions to each other
5 in the axial direction.
[0085] Thus disposing the respective turbine blade rows such that the steam
flowing through the high-pressure turbine blade row 22 and the steam flowing
through the intermediate-pressure turbine blade row 24 flow in the opposite
directions to each other in the axial direction, and the steams flowing through the
10 first low-pressure turbine blade row 26A and the second turbine blade row 26B,
respectively, flow in the opposite directions to each other in the axial direction, it is
possible to balance a thrust load acting on the rotor shaft 28.
Furthermore, since the respective turbine blade rows are disposed such that
the steams flowing through the third low-pressure turbine blade row 26C and the
15 fourth low-pressure turbine blade row 26D, respectively, flow in the opposite
directions to each other in the axial direction, it is possible to balance the thrust load
acting on the rotor shaft 28 more effectively.
[0086] FIG. 3 is a schematic cross-sectional view of the exhaust chamber 50 or
the exhaust chamber 52 for the steam turbine facility 4 according to an embodiment,
20 and is a cross-sectional view taken along line A-A of FIG. 2 or line A’-A’ of FIG. 2.
In some embodiments, as shown in FIG. 3, the exhaust chamber 50, 52 for
the steam turbine facility 4 may include the exhaust chamber outlet 51, 53
positioned on the lateral side thereof.
The lateral side of the exhaust chamber 50, 52 refers to a direction away
25 from the center axis O of the rotor shaft 28 in the horizontal direction, when the
exhaust chamber 50, 52 is viewed from the axial direction (see FIG. 3).
28
[0087] In this case, the steam having passed through the first/second low-pressure
turbine blade row 26A, 26B and the third/fourth low-pressure turbine blade row is
laterally exhausted toward the condenser 34 via the exhaust chamber outlet 51, 53
disposed on the lateral side of the exhaust chamber 50, 52. That is, since the
condenser 34 can be disposed on the lateral side of 5 the exhaust chamber 50, 52, it
is possible to reduce the size of the steam turbine facility 4 in the height direction,
as compared with a case in which the condenser 34 is positioned below the exhaust
chamber 50, 52. Therefore, it is possible to reduce the facility cost of the steam
turbine facility 4 more effectively.
10 [0088] Note that the one condenser 34 may be disposed for each casing. That is,
the one condenser 34 may be disposed in correspondence with the pair of exhaust
chambers 50 provided for the first casing 80, and the one condenser 34 may be
disposed in correspondence with the pair of exhaust chambers 52 provided for the
second casing 82.
15 [0089] Embodiments of the present invention were described in detail above, but
the present invention is not limited thereto, and also includes an embodiment
obtained by modifying the above-described embodiments and an embodiment
obtained by combining these embodiments as appropriate.
[0090] Further, in the present specification, an expression of relative or absolute
20 arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”,
“centered”, “concentric” and “coaxial” shall not be construed as indicating only the
arrangement in a strict literal sense, but also includes a state where the arrangement
is relatively displaced by a tolerance, or by an angle or a distance whereby it is
possible to achieve the same function.
25 For instance, an expression of an equal state such as “same” “equal” and
“uniform” shall not be construed as indicating only the state in which the feature is
29
strictly equal, but also includes a state in which there is a tolerance or a difference
that can still achieve the same function.
Further, an expression of a shape such as a rectangular shape or a
cylindrical shape shall not be construed as only the geometrically strict shape, but
also includes a shape with unevenness or chamfered 5 corners within the range in
which the same effect can be achieved.
As used herein, the expressions “comprising”, “including” or “having” one
constitutional element is not an exclusive expression that excludes the presence of
other constitutional elements.
10
Reference Signs List
[0091]
1 Combined cycle plant
2 Gas turbine facility
15 4 Steam turbine facility
6 Heat recovery steam generator
7 Stator vane
8 Rotor blade
10 Compressor
20 12 Combustor
14 Turbine
16 Rotational shaft
18 Generator
20 Outer casing
25 20a Inner circumferential surface
21 Outer casing
30
21a Inner circumferential surface
22 High-pressure turbine blade row
24 Intermediate-pressure turbine blade row
26A First low-pressure turbine blade row
5 26B Second low-pressure turbine blade row
26C Third low-pressure turbine blade row
26D Fourth low-pressure turbine blade row
27 First shaft part
28 Rotor shaft
10 29 Second shaft part
30A, 30B Radial bearing
31A, 31B Radial bearing
32 Generator
34 Condenser
15 36 Inner casing
36a Outer circumferential surface
37 Inner casing
37a Outer circumferential surface
38 High-pressure inlet pipe
20 40 High-pressure outlet pipe
42 Intermediate-pressure inlet pipe
44 Low-pressure inlet pipe
48 Guide member
49 Guide member
25 50 Exhaust chamber
51 Exhaust chamber outlet
31
52 Exhaust chamber
53 Exhaust chamber outlet
54 Flow guide
55 Flow guide
5 56 Insulator
57 Insulator
58 Insulator
59 Insulator
60 Seal part
10 61 Seal part
62 Branched channel
63 Seal part
64 First inner channel
65 Connection pipe
15 66 Second inner channel
68 Thrust bearing
70 Coupling
74 Steam introduction path
80 First casing
20 82 Second casing
84 Bearing cone part
86 Bearing cone part
O Center axis
32
I/We Claim:
1. A steam turbine facility, comprising:
a rotor shaft;
a high-pressure turbine blade 5 row and an intermediate-pressure turbine
blade row disposed on the rotor shaft;
a first low-pressure turbine blade row and a second low-pressure turbine
blade row disposed on the rotor shaft on both sides of the intermediate-pressure
turbine blade row, respectively; and
10 a third low-pressure turbine blade row and a fourth low-pressure turbine
blade row disposed on the rotor shaft on both sides of the high-pressure turbine
blade row, respectively,
wherein the steam turbine facility is configured such that steam having
passed through the intermediate-pressure turbine blade row is divided to flow into
15 the first low-pressure turbine blade row, the second low-pressure turbine blade row,
the third low-pressure turbine blade row, and the fourth low-pressure turbine blade
row.
2. The steam turbine facility according to claim 1, further comprising:
20 a first pair of radial bearings and a second pair of radial bearings for
rotatably supporting the rotor shaft,
wherein the intermediate-pressure turbine blade row, the first low-pressure
turbine blade row, and the second low-pressure turbine blade row are disposed on
the rotor shaft in a bearing span of the first pair of radial bearings, and
25 wherein the high-pressure turbine blade row, the third low-pressure turbine
blade row, and the fourth low-pressure turbine blade row are disposed on the rotor
33
shaft in a bearing span of the second pair of radial bearings.
3. The steam turbine facility according to claim 1 or 2, further comprising:
a first casing for accommodating the intermediate-pressure turbine blade
row, the first low-pressure turbine blade row, 5 and the second low-pressure turbine
blade row; and
a second casing for accommodating the high-pressure turbine blade row,
the third low-pressure turbine blade row, and the fourth low-pressure turbine blade
row.
10
4. The steam turbine facility according to claim 3, further comprising:
a thrust bearing for rotatably supporting the rotor shaft,
wherein the thrust bearing is disposed between the first casing and the
second casing.
15
5. The steam turbine facility according to any one of claims 1 to 4,
wherein the first low-pressure turbine blade row is disposed downstream
of the intermediate-pressure turbine blade row in a steam flow direction in the
intermediate-pressure turbine blade row, and
20 wherein the steam turbine facility includes a branched channel for
introducing a part of a steam flow from the intermediate-pressure turbine blade row
toward the first low-pressure turbine blade row to the second low-pressure turbine
blade row, the third low-pressure turbine blade row, and the fourth low-pressure turbine blade row.
6. The steam turbine facility according to claim 5, comprising:
a first casing for accommodating the intermediate-pressure turbine blade
row, the first low-pressure turbine blade row, and the second low-pressure turbine blade row; and
a second casing for accommodating the high-pressure turbine blade row,
the third low-pressure turbine blade row, 5 and the fourth low-pressure turbine blade row, wherein the branched channel includes:
a first inner channel disposed so as to cause an inlet side of the
first low-pressure turbine blade row and an inlet side of the second low-pressure turbine blade row to communicate with each other, in the first casing; a second inner channel disposed so as to cause an inlet side of the
third low-pressure turbine blade row and an inlet side of the fourth low-pressure turbine blade row to communicate with each other, in the second casing; and a connection pipe having an end connected to the first inner
channel in the first casing and another end connected to the second inner channel in the second casing.
7. The steam turbine facility according to claim 5 or 6, comprising:
a first casing for accommodating the intermediate-pressure turbine blade
row, the first low-pressure turbine blade row, and the second low-pressure turbine blade row,
wherein the first casing includes:
an inner casing for accommodating the intermediate-pressure
turbine blade row; and an outer casing for accommodating the inner casing, and at least a part of the first low-pressure turbine blade row and the second low-pressure turbine blade row, and wherein the branched channel is formed at least partially by an outer surface of the inner casing and an inner surface of the outer casing.
8. The steam turbine facility according 5 to claim 5 or 6, comprising:
a first casing for accommodating the intermediate-pressure turbine blade
row, the first low-pressure turbine blade row, and the second low-pressure turbine blade row, wherein the first casing includes:
an inner casing for accommodating the intermediate-pressure
turbine blade row; and an outer casing for accommodating the inner casing, and at least a part of the first low-pressure turbine blade row and the second low-pressure turbine blade row, and
wherein the branched channel is formed at least partially by a pipe passing
outside the outer casing.
9. The steam turbine facility according to any one of claims 5 to 8, further
comprising: a steam introduction path connected to the branched channel, for
introducing steam having a pressure lower than a pressure of steam in an inlet of the first low-pressure turbine blade row.
10. The steam turbine facility according to any one of claims 1 to 9,
wherein the steam turbine facility is configured such that steam flowing
through the high-pressure turbine blade row and steam flowing through the
intermediate-pressure turbine blade row flow in opposite directions to each other in an axial direction,
wherein the steam turbine facility is configured such that steam flowing
through the first low-pressure turbine blade row and steam flowing through the
second low-pressure turbine blade row flow 5 in opposite directions to each other in the axial direction, and
wherein the steam turbine facility is configured such that steam flowing
through the third low-pressure turbine blade row and steam flowing through the
fourth low-pressure turbine blade row flow in opposite directions to each other in the axial direction.
11. The steam turbine facility according to any one of claims 1 to 10, further
comprising: an exhaust chamber for discharging steam from the first low-pressure turbine blade row and from the second low-pressure turbine blade row toward a condenser, wherein the exhaust chamber has an exhaust chamber outlet disposed on a lateral side thereof.
12. The steam turbine facility according to any one of claims 1 to 11, further
comprising:
a condenser for condensing steam from the first low-pressure turbine blade
row and from the second low-pressure turbine blade row.
13. A combined cycle plant, comprising:
a gas turbine facility;
a boiler for generating steam by heat of a discharged gas from the gas
turbine facility; and
the steam turbine facility according to any one of claims 1 to 12,
wherein the steam turbine facility is configured to be driven by the steam
generated by the boiler.