U.S. patent application number 11/430010 was filed with the patent office on 2006-09-14 for steam turbine.
This patent application is currently assigned to HITACHI, LTD.. Invention is credited to Katsutoshi Higuma, Yoshifumi Kubo, Yasuhiro Oda, Masaki Takahashi, Akitaka Tateishi, Akio Umino.
Application Number | 20060201155 11/430010 |
Document ID | / |
Family ID | 34386371 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060201155 |
Kind Code |
A1 |
Takahashi; Masaki ; et
al. |
September 14, 2006 |
Steam turbine
Abstract
In a steam turbine plant in which a turbine casing containing a
turbine is constituted of an upper-half casing and a lower-half
casing, nozzles are provided to the upper-half casing and a steam
supplied through main steam piping lines are delivered into the
upper-half casing. Main steam pipes for supplying a steam from
respective main valves to the respective nozzles are each formed so
as to be dividable in a position out of the installation area of
the upper-half casing.
Inventors: |
Takahashi; Masaki; (Hitachi,
JP) ; Kubo; Yoshifumi; (Takahagi, JP) ;
Tateishi; Akitaka; (Hitachinaka, JP) ; Higuma;
Katsutoshi; (Takahagi, JP) ; Umino; Akio;
(Hitachi, JP) ; Oda; Yasuhiro; (Utsunomiya,
JP) |
Correspondence
Address: |
MATTINGLY, STANGER, MALUR & BRUNDIDGE, P.C.
1800 DIAGONAL ROAD
SUITE 370
ALEXANDRIA
VA
22314
US
|
Assignee: |
HITACHI, LTD.
|
Family ID: |
34386371 |
Appl. No.: |
11/430010 |
Filed: |
May 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10957710 |
Oct 5, 2004 |
7065968 |
|
|
11430010 |
May 9, 2006 |
|
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Current U.S.
Class: |
60/645 |
Current CPC
Class: |
F05D 2230/70 20130101;
F01K 13/00 20130101; F01D 9/06 20130101; F01D 25/24 20130101 |
Class at
Publication: |
060/645 |
International
Class: |
F01K 13/00 20060101
F01K013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 6, 2003 |
JP |
2003-346477 |
Claims
1-6. (canceled)
7. A steam turbine plant comprising: a boiler equipment for
generating a drive steam; a steam turbine driven by said steam from
said boiler equipment; a power generator driven by said steam
turbine; a main steam piping line connecting said boiler equipment
and said steam turbine; a main valve provided in way of said main
steam piping line; and a condenser for condensing a team discharged
from said steam turbine; and wherein said steam turbine includes a
turbine, a turbine casing containing said turbine, and a nozzle
provided to said turbine casing and to which said main steam piping
line is connected; said turbine casing includes an upper-half
casing and a lower-half casing, and said nozzle is provided to said
upper-half casing; and said main valve is set at a level higher
than the setting level of said steam turbine.
8. The steam turbine plant according to claim 7, wherein a portion
of said main steam piping line connecting said main valve and said
nozzle is formed so as to be dividable in a position out of an
installation area of the upper-half casing.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a steam turbine plant.
[0003] 2. Description of the Related Art
[0004] Conventional steam turbine plants include one disclosed in
JP, A 60-159310, for example. JP, A 60-159310 discloses a steam
turbine having a dual casing structure composed of an inner and an
outer casing wherein the space between the inner and outer casings
is divided by a partition wall into a first steam passage allowing
part of main steam to pass along the outer surface of the inner
casing and a second steam passage allowing cooling steam to pass
along the inner surface of the outer casing, and wherein an
opening/closing device is provided to each of the first and second
steam passages, whereby thermal stress in the inner and outer
casings is reduced even if this steam turbine is frequently started
and stopped. JP, A 60-159310 further discloses a structure wherein
main steam piping line for supplying a steam from a boiler is
connected to an upper portion of the outer casing, and wherein an
exhaust hole is provided for discharging exhaust steam that has
worked at various stages of the turbine and sending it to a next
turbine.
SUMMARY OF THE INVENTION
[0005] Generally, in order to facilitate the removal of the
upper-half casing when performing maintenance of a steam turbine,
the main steam piping line for supplying a main steam from steam
generating equipment such as boiler equipment to the steam turbine
is configured to be connected to a lower-half casing. As a result,
the steam turbine requires a space below it for installing pipes of
the main steam piping line having a large bore size. This increases
the installation height of the turbine, resulting in a high-rise of
the turbine building.
[0006] On the other hand, as in the above-described JP, A
60-159310, in the case where main steam piping line connected to
the turbine casing is configured to be connected to an upper
portion of the turbine casing, when attempting to disconnecting and
conveying the turbine casing upon maintenance, the main steam
piping line connected to the upper portion of the turbine casing
unfavorably interferes with the disconnecting and conveying of the
turbine casing, thereby making the maintenance operation
troublesome.
[0007] It is an object of the present invention to provide a steam
turbine plant which allows the setting level of the steam turbine
to be lowered and enables the maintenance of the steam turbine to
be facilitated.
[0008] To achieve the above-mentioned object, the present invention
provides a steam turbine plant in which a turbine casing containing
a turbine is constituted of an upper-half casing and a lower-half
casing, the steam turbine plant comprising a main steam piping
line, and a nozzle provided to the upper-half casing and through
which a steam supplied through the main steam piping line is
delivered into the upper-half casing, wherein the main steam piping
line includes a main steam pipe for supplying a steam from a main
valve to the nozzle and the main steam pipe is formed so as to be
dividable in a position out of an installation area of the
upper-half casing.
[0009] According to the present invention, a steam turbine plant
can be provided that allows the setting level of the steam turbine
to be lowered and enables the maintenance of the steam turbine to
be facilitated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a view (sectional view) showing a structure of a
first embodiment of the present invention in which main steam pipes
are each connected to an upper-half casing of a steam turbine,
according to a first embodiment of the present invention;
[0011] FIG. 2 is a view (plan view) showing a structure in which
the main steam pipes are each connected to the upper-half casing
according to the first embodiment;
[0012] FIG. 3 is an overall schematic plan view of a steam turbine
plant according to the first embodiment;
[0013] FIG. 4 is a view showing a state where the steam turbine
casing has moved due to thermal expansion;
[0014] FIG. 5 is a view showing a structure of a second embodiment
of the present invention in which the main steam pipes are each
connected between the upper-half and lower-half casings;
[0015] FIG. 6 is a view showing a structure in which the main steam
pipes are each sandwiched between the upper-half and lower-half
casings according to a modulation of the second embodiment;
[0016] FIG. 7 is a view showing a structure of grooves and main
steam pipe flanges at the connection portions between the
upper-half and lower-half casings and the main steam pipes
according to another modulation of the second embodiment; and
[0017] FIG. 8 is a view showing a structure for absorbing thermal
expansion.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Hereinafter, preferred embodiments of the present invention
will be described with reference to the accompanying drawings.
First Embodiment
[0019] FIG. 3 is a schematic view of a steam turbine plant
according to a first embodiment of the present invention. The steam
turbine plant according to this embodiment comprises steam turbines
100 driven by steam, boiler equipment 500 for generating drive
steam, a power generator 600 driven with rotation of the steam
turbine 100, main steam piping lines 10 for supplying steam
generated by the boiler equipment 500 to the turbines 100', and an
axial flow condenser 720 disposed in an axial direction of the
steam turbines 100 for condensing a steam discharged from the steam
turbines 100. The steam turbines 100 and the power generator 600
are installed on a steam turbine mount surface 850. The steam
turbines 100 includes a high-pressure steam turbine 110 and a
middle-pressure steam turbine 130. The main steam piping lines 10
comprise a high-pressure main steam piping line 210 for introducing
a high-pressure steam generated by the boiler equipment 500 to the
high-pressure steam turbine 110, and a middle-pressure main steam
piping line 230 (high-temperature reheat steam piping line) for
introducing a middle-pressure steam to the middle-pressure steam
turbine 130, the middle-pressure steam being obtained by reheating
an exhaust gas returned from the high-pressure steam turbine 110 by
a reheater (not shown) in the boiler 500. The exhaust gas from the
high-pressure steam. turbine 110 is returned to the boiler
equipment 500 through a low temperature reheat steam piping line
220. Also, the steam turbines 100 to which the main steam piping
lines 10 are connected, comprise nozzles 105 at steam inlets of
turbine casings to be described later.
[0020] FIG. 1 is a sectional view of the steam turbine plant
according to this embodiment as seen in a turbine axial direction.
High-pressure steam and middle-pressure steam (reheat steam)
generated by the above-described boiler equipment 500 are supplied
to the steam turbine 100 through the main steam piping lines 10
(high-pressure steam piping lines 210 and middle-pressure steam
piping lines (high-temperature reheat piping lines) 230), main
valves 90 such as main steam adjusting valves and stop valves. The
main steam piping lines 10 each comprises a main steam pipe 10A for
introducing steam from the main valve to the steam turbine 100,.
and the main steam pipe 10A comprises a first main steam pipe
(hereinafter, a main steam pipe 11) and a second main steam pipe
(hereinafter, a short pipe 12). A steam having past through the
main steam pipe 11 and the short pipe 12 is supplied to the steam
turbine 100 through the nozzle 105 provided to the upper-half
casing 101 of the steam turbine 100. The connection portion between
the main steam pipe 11 and the short pipe 12 and the connection
portion between the short pipe 12 and the nozzle 105 are provided
with flanges, respectively. Specifically, a main steam pipe flange
14 is formed in the connection portion between the main steam pipe
11 and the short pipe 12, while a main steam pipe nozzle portion
flange 106 is formed in the connection portion between the short
pipe 12 and the nozzle 105. In the example illustrated in FIG. 1,
the short pipes 12 are connected to the casing via the respective
flanges 106, but they may instead be formed integrally with the
casing. The casing of the steam turbine 100 comprises an upper-half
casing 101 and a lower-half casing 102. The nozzles 105, each
serving as a steam inlet of the steam turbine 100, are installed to
the upper-half casing 101 of the steam turbine 100. By virtue of
this configuration, as shown in FIG. 3, the main steam piping lines
10 can be run in higher places than the axial center line of the
steam turbines 100. This eliminates restriction by the main steam
piping lines with respect to the installation height of the steam
turbine 100, thereby allowing the steam turbine 100 itself to be
installed at a lower place.
[0021] Meanwhile, the main steam piping lines 10 generate thermal
expansion and contraction due to the temperature difference between
a plant operation time and a plant stop time, thereby generating
reaction force moments with respect to the boiler equipment. 500
and the steam turbine 100 which are fixedly mounted. As shown in
FIG. 4, even when the main steam piping lines 10 are connected to
the lower-half casing 102 from below the steam turbine 100, the
position of the steam turbine 100 is not changed by the
above-described reaction forces, because the reaction forces are
usually held down by the weights of the lower-half casing 102, a
turbine rotor 103, a turbine blade 104, and the upper-half casing
101. However, when the plant is adjusted and installed under the
condition where the piping lines have been thermally expanded, for
the purpose of preventing the piping lines from being subjected to
a reaction force during operation, an inverse reaction force occurs
at an operation stop time due to the contraction of the main steam
piping lines 10. As a result, when the upper-half casing 101,
turbine rotor 103, turbine blade 104, etc. are removed during
maintenance or the like, the overall weight of the steam turbine
100 reduces, and therefore, the lower-half casing 102, which is
left unremoved, may unfavorably moves during the maintenance or the
like, due to thermal contraction of the main steam piping lines
10.
[0022] On the other hand, in this embodiment, the main steam piping
lines for supplying a steam to the steam turbine 100 is connected
to the upper-half casing 101, and further the short pipes 12 can be
removed during maintenance. Therefore, even when the disconnection
of the upper-half casing 101,. turbine rotor 103, turbine blade 104
and the like during maintenance reduces the weight over the
lower-half casing 102, the lower-half casing 102 is not subject to
thermal expansion and the like of the main steam piping lines,
thereby eliminating the occurrence of movement of the lower-half
casing 102. In other words, as shown in FIG. 1, when the main steam
piping lines 10 are each connected to the upper-half casing 101
from above, the main steam piping lines 10 are perfectly separated
from the lower-half casing 102 during maintenance, thereby
preventing thermal expansion and contraction of the main steam
piping lines 10 (main steam pipe 11) from transmitting to the
lower-half casing 102.
[0023] In the conventional art, in which the main steam piping
lines 10 are each connected to the lower-half casing 102 as shown
in FIG. 4, the removal of the upper-half casing 101 can be easily
performed during maintenance since pipes and the like are not
connected to the upper-half casing 102. However, as shown in FIG.
1, when the main steam piping lines 10 are each connected to the
upper-half casing 101, it is necessary to separate the main steam
piping lines 10 from the upper-half casing 101 in order to
disconnect the upper-half casing 101. For this purpose, in this
embodiment, there are provided the flanges (a main steam pipe
flange 14 and a main steam pipe nozzle portion flange 106) for
separating the main steam pipe 10A from the upper-half casing 101.
In particular, the main steam pipe flange is disposed between the
nozzle 105 and the main valve 90 in a position out of the
installation area of the upper-half casing 101 as viewed in a
horizontal plane as shown in FIG. 2.
[0024] When the upper-half casing 101 of the steam turbine 100 is
to be conveyed after having been disassembled, the upper-half
casing 101 is first moved in a vertically upward direction, and
then conveyed in the other direction from the position where no
interfering object has come to be found therearound. Therefore,
when the upper-half casing 101 is to be conveyed in the vertically
upward direction, it is desirable that the main steam pipes 11 and
the main valves 90 disconnected from the upper-half casing 101 do
not interfere therewith. For this purpose, as shown in FIG. 2, the
main steam pipe flanges 14 for separating the main steam pipes 11
from the upper-half casing 101 are each located in a position
having a wider width than expected to cause interference with the
upper-half casing 101 upon conveyance thereof in the vertically
upward direction. By providing the flanges 14 in such positions and
separating the short pipes 12 from the main steam pipes 11 at the
flanges 14 upon maintenance, it is possible to eliminate any
obstacles above the upper-half casing 101, and easily perform
disconnection work and conveyance operation.
[0025] Furthermore, in this embodiment, there are provided the main
steam pipe nozzle portion flanges 106. When the main steam pipe
flanges 14 are each disposed far apart from the nozzle 105, the
short pipes 12 have to become correspondingly longer, thereby
unfavorably increasing their weights. Therefore, when the
upper-half casing 101 is conveyed with the short pipes 12 connected
therewith, the weights to be conveyed become heavier, resulting in
inconvenience for conveyance operation. In addition, there occurs
the need for a wide range of space for placing the upper-half
casing 101 after conveyance. In contrast, in this embodiment, when
the upper-half casing 101 is disconnected and conveyed, the short
pipes 12 are removed from the main steam pipe nozzle portion
flanges 106, thereby facilitating the conveyance of the upper-half
casing 101. The length of the short pipe 12 should be designed to
be a length such that the main valve 90 takes a position that does
not interfere with the upper-half casing 101 when the upper-half
casing 101 is disconnected and conveyed.
[0026] The steam turbine 100 with the above-described structure may
also be applied to a conventional high-floor power generation
plant. Moreover, this steam turbine 100 can be applied to a
low-floor power generation plant that has been difficult to realize
when the main steam piping lines 10 are connected to the lower-half
casing 102 as in the conventional steam turbine 100.
[0027] In this way, the high-pressure and middle-pressure or reheat
main steam piping lines 10 that have conventionally been connected
to the lower-half casing 102, are connected to the upper-half
casing 101 as shown in FIG. 1, and further, as shown in FIG. 2, the
main valves 90 for the main steam piping lines 10 are disposed in
proper positions such as not to interfere with the
disconnection/conveyance of the upper-half casing 101 upon
maintenance of the steam turbine 100, that is, in the positions
wider than that of the upper-half casing 101 of the steam turbine
100. Specifically, the main steam pipes 10A are each formed so as
to be dividable in a position out of the installation area of the
upper-half casing 101 as viewed in a horizontal plane as shown in
FIG. 2. In other words, the flanges 14 are each formed as dividing
means in a way of the main steam pipe 10A connecting the main valve
90 and the nozzle 105, and these flanges 14 are each located in a
position out of the installation area of the upper-half casing 101
as viewed in a horizontal plane as shown in FIG. 2. Also, as shown
in FIG. 1, in order that the main steam pipes 10A (short pipes 12)
become separable from the upper-half casing 101 of the steam
turbine 100, the main steam pipe nozzle portion flanges 106 are
each provided in a position where the main steam pipes 10A (short
pipes 12) are connected to the nozzles 105 of the upper-half casing
101. With those structures, it is possible to lower the setting
level of the steam turbine and to facilitate the maintenance of the
steam turbine.
Second Embodiment
[0028] FIG. 5 is a sectional view of the steam turbine plant
according to a second embodiment as viewed in a turbine axial
direction. As illustrated in FIG. 5, the connection portion between
the steam turbine 100 and each of the main steam pipes 10A
described with reference to FIG. 1 may be connected to the junction
between the upper-half casing 101 and the lower-half casing 102, as
shown in FIG. 5. One method for establishing such connection is to
sandwich each of the main steam pipes 10A between the upper-half
and lower-half casings, as shown in FIG. 6. In this case, also,
just as in the case of the foregoing, the main valves 90 each needs
to be disposed in a position such as not to interfere with the
disconnection/conveyance of the upper-half casing 101 of the steam
turbine 100, but it is foreseen that each of the main valves 90
would not interfere with the upper-half casing 101 or the
interference would be small should it occur even when the main
valves are disposed closest to the steam turbine 100. As a result,
it can be expected that the short pipe 12 between each of the main
steam pipe 11 and the steam turbine 100 can be omitted. Also, in
this structure, in which the main steam pipes 10A are each
sandwiched between the upper-half casing 101 and the lower-half
casing 102 of the steam-turbine 100, the disconnection of the
upper-half casing 101 of the steam turbine 100 is implementable
without separating the main steam pipes 100A from the upper-half
casing 101 by the flanges 14 or the like. However, in the state
where the main steam pipes 10A remain connected to the lower-half
casing 102 of the steam turbine 100, there is a possibility that
the lower-half casing 102 move due to reaction forces-caused by
thermal expansion and contraction of the main steam pipes 10A upon
operation and stoppage of the steam turbine 100. When there is
apprehension about such a movement of the lower-half casing 102, it
is desirable that the steam turbine 100 is connected with the main
steam pipes 11 through the short pipes 12 as described above. By
separating the short pipes 12 from the main steam pipes 11 and the
lower-half casing 102 after the upper-half casing 101 of the steam
turbine 100 is disassembled and conveyed, it is possible to
eliminate influences of reaction forces with respect to the
lower-half casing 102 that would be otherwise caused by thermal
expansion and contraction.
[0029] Also, when the main steam pipes 10A are each connected to
the casings of the steam turbine 100 by sandwiching them between
the upper-half casing 101 and the lower-half casings 102 of the
steam turbine 100 as described above, an end portion of each of the
main steam pipes 10A is formed with a flange structure 13 as shown
in FIG. 7, and each of the main steam pipe connecting portions of
the upper-half casing 101 and the lower-half casing 102 is formed
with a groove structure 107 into which the above-described end
portion of each of the main steam pipes 10A just fits; whereby each
of the main steam pipes 10A can be rotated about a pipe axis 15
even in the state of being connected to the casings of the steam
turbine 100.
[0030] Here, each of the main steam pipes 10A is installed to
extend in a route such that it is bent in the direction
perpendicular to the central axis of the steam turbine 100 and the
central axis of each of the main steam pipes 10A exiting the steam
turbine 100, and thereafter again each of them is bent in the axial
direction of the steam turbine 100, whereby a reaction force due to
thermal expansion and contraction of the main steam piping lines 10
upon operation and stoppage of the steam turbine 100 is not applied
thereto. This allows, as shown in FIG. 8, the amount of thermal
expansion to be absorbed by rotation of the connection portion
between the main steam pipe 10A and the steam turbine 100 even if
the main steam piping lines 10 are subjected to thermal expansion
in the axial direction of the steam turbine 100 upon operation of
the steam turbine 100.
[0031] By singly adopting one of the structures described above, or
combining some of these structures, it is possible to lower the
installation height of the steam turbine. This allows a turbine
building to be designed to be low, or enables an outdoor
installation method without a turbine building to be applied. In
particular, when a steam turbine with a low height is installed
outdoors without a turbine building, a small-sized crane requiring
no access to a high position can be used as a crane for hoisting
the upper-half casing, turbine rotor, and the like upon maintenance
of the steam turbine. This makes a required maintenance space
smaller, and also allows safe and economical maintenance to be
implemented. Moreover, this eliminates the need to support reaction
forces due to heat transfer by the lower-half casing of the steam
turbine and a foundation of the steam turbine when the steam
turbine casing is removed, thereby reducing the possibility of
accidents. Furthermore, the capability of making the turbine
foundation low enables an economical power generation plant that
reduces the cost of civil engineering to be constructed.
* * * * *