U.S. patent application number 15/417977 was filed with the patent office on 2017-09-07 for steam turbine plant.
The applicant listed for this patent is Mitsubishi Hitachi Power Systems, Ltd.. Invention is credited to Norihiro IYANAGA, Miyuki KAWATA, Eunkyeong KIM, Fumiyuki SUZUKI, Kazunori YAMANAKA, Tatsuro YASHIKI, Takuya YOSHIDA, Yasuhiro YOSHIDA.
Application Number | 20170254225 15/417977 |
Document ID | / |
Family ID | 57956145 |
Filed Date | 2017-09-07 |
United States Patent
Application |
20170254225 |
Kind Code |
A1 |
KIM; Eunkyeong ; et
al. |
September 7, 2017 |
Steam Turbine Plant
Abstract
A steam turbine plant of the present invention includes a heat
source device that heats a low temperature fluid by a heat source
medium to obtain a high temperature fluid, a steam generating
device that generates steam by heat exchange with the high
temperature fluid, a steam turbine that is driven by the steam, a
heating flow path that is disposed on an outer surface of a casing
of the steam turbine, a high temperature fluid supply passage that
is branched from a flow path of the high temperature fluid in the
steam generating device, is connected to the heating flow path, and
supplies the high temperature fluid to the heating flow path, and a
high temperature fluid flow rate regulating device that regulates a
flow rate of the high temperature fluid flowing through the high
temperature fluid supply passage.
Inventors: |
KIM; Eunkyeong; (Tokyo,
JP) ; YOSHIDA; Yasuhiro; (Tokyo, JP) ;
YOSHIDA; Takuya; (Tokyo, JP) ; YASHIKI; Tatsuro;
(Tokyo, JP) ; KAWATA; Miyuki; (Tokyo, JP) ;
YAMANAKA; Kazunori; (Yokohama, JP) ; IYANAGA;
Norihiro; (Yokohama, JP) ; SUZUKI; Fumiyuki;
(Yokohama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Hitachi Power Systems, Ltd. |
Yokohama |
|
JP |
|
|
Family ID: |
57956145 |
Appl. No.: |
15/417977 |
Filed: |
January 27, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 25/10 20130101;
F01K 7/16 20130101; F01K 21/045 20130101; F01K 13/02 20130101; Y02E
20/16 20130101; F01K 11/02 20130101; F01D 11/24 20130101; F01D
25/12 20130101 |
International
Class: |
F01K 21/04 20060101
F01K021/04; F01K 13/02 20060101 F01K013/02; F01K 11/02 20060101
F01K011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 7, 2016 |
JP |
2016-043739 |
Claims
1. A steam turbine plant comprising: a heat source device that
heats a low temperature fluid by a heat source medium to obtain a
high temperature fluid; a steam generating device that generates
steam by heat exchange with the high temperature fluid obtained by
the heat source device; a steam turbine that is driven by the steam
generated by the steam generating device; a heating flow path that
is disposed on an outer surface of a casing of the steam turbine or
inside a member configuring the casing; a high temperature fluid
supply passage that is branched from a flow path of the high
temperature fluid in the steam generating device, is connected to
the heating flow path, and supplies the high temperature fluid to
the heating flow path; and a high temperature fluid flow rate
regulating device that regulates a flow rate of the high
temperature fluid flowing through the high temperature fluid supply
passage.
2. The steam turbine plant according to claim 1, further
comprising: a heating control circuit that controls the high
temperature fluid flow rate regulating device such that the flow
rate of the high temperature fluid flowing through the high
temperature fluid supply passage is increased, as differential
thermal expansion between a rotor and the casing of the steam
turbine is increased.
3. The steam turbine plant according to claim 1, wherein the
heating flow path is disposed on the outer surface of the casing of
the steam turbine or inside the member configuring the casing, and
on a portion to be a relatively low temperature at a time of
starting a plant, the plant further comprising: a cooling flow path
that is disposed on the outer surface of the casing or inside the
member configuring the casing, and on a portion to be a relatively
high temperature at the time of starting the plant; a low
temperature fluid supply passage that supplies the low temperature
fluid to the cooling flow path; and a low temperature fluid flow
rate regulating device that regulates a flow rate of the low
temperature fluid flowing through the low temperature fluid supply
passage.
4. The steam turbine plant according to claim 3, further
comprising: a cooling control circuit that controls the low
temperature fluid flow rate regulating device so that the flow rate
of the low temperature fluid flowing through the cooling flow path
is increased, as temperature difference between a portion where the
cooling flow path is disposed and a portion where the heating flow
path is disposed is increased.
Description
BACKGROUND OF THE INVENTION
[0001] Field of the Invention
[0002] The present invention relates to a steam turbine plant
provided with a steam turbine such as a combined cycle power plant
or a coal-fired power plant.
[0003] Background Art
[0004] Since the power generation amount varies greatly in a power
generation plant using renewable energy represented by wind power
generation or solar power generation, fast start-up (in other
words, starting in a shorter period of time) of a power generation
plant (steam turbine plant) provided with a steam turbine is
required for the stabilization of the power system.
[0005] In the fast start-up of the steam turbine, since a rotor of
the steam turbine and a casing for housing the rotor are exposed to
high temperature steam entering the steam turbine, the rotor and
the casing are heated, and thermally expanded, and thus extend
particularly in a turbine axial direction. Since a structure and
heat capacity of the rotor are different from that of the casing,
difference between thermal expansion of the rotor and that of the
casing (hereinafter, referred to as the differential thermal
expansion between the rotor and the casing) is generated.
[0006] In the fast start-up of the steam turbine, it is known that
thermal deformation of the casing occurs. Specifically, for
example, since the casing is divided into an upper half and a lower
half, and their structure and heat capacity are different,
temperature difference is generated. The high temperature side is
thermally expanded greater than the low temperature side, and thus
heat deformation is generated so as to shrink along the side of the
low temperature side (refer to Rainer Quinkertz, Thomas Thiemann,
Kai Gierse, 2011, "Validation of advanced steam turbine
technology-A case study of an ultra super critical steam turbine
power plant", Proceedings of ASME Turbo Expo 2011, GT 2011-45816).
There is a flange portion for the upper half and lower half of the
casing are joined by screws, and the temperature of the inner
circumferential surface of the flange portion is increased, later
than the cylinder portion which is exposed to the high temperature
steam. Therefore, the thermal deformation caused by temperature
distribution is generated (for example, refer to John McElhaney,
2008, "Distortion Compensation by shape modification of complex
turbine geometries in the presence of high temperature gradients",
Proceedings of ASME Turbo Expo 2008, GT2008-50757).
[0007] When the differential thermal expansion between the rotor
and the casing or the thermal deformation of the casing described
above is increased, the rotor (rotating portion) and the casing
(stationary portion) are damaged in contact with each other.
Therefore, it is required to control the amount of heat input to
the steam turbine so that the differential thermal expansion falls
within a predetermined limit value.
[0008] For a method of controlling the amount of heat input to the
steam turbine, a method of generating steam by using exhaust heat
from a gas turbine compressor and of preheating the steam turbine
by using this steam in a combined cycle power plant is known (for
example, refer to JP-A-2013-133825). A method of disposing a
protective shield to protect against direct action of steam in the
steam passage of the steam turbine is known (for example, refer to
JP-A-2010-138916). A method of mounting the heater to the casing of
the steam turbine is known (for example, refer to
JP-A-9-88510).
SUMMARY OF THE INVENTION
[0009] As described in JP-A-2013-133825, since heat of fluid that
does not finish a work in a gas turbine is used, in a method using
steam generated by using exhaust heat from a gas turbine
compressor, there is a possibility of lowering efficiency of the
gas turbine (heat source device). There is a need for an
installation of a heat exchanger and changes of control circuits
that control the gas turbine.
[0010] As described in JP-A-2010-138916, a method using the steam
that flows in the steam passage of a steam turbine can use the heat
only when the steam is generated from a steam generating device.
Since the steam is normally and partially branched from a steam of
the main stream by a protective shield, there is a possibility of
lowering efficiency at rated load of the steam turbine.
[0011] As described in JP-A-9-88510, a method using a heater is
required an external power supply for securing the power of the
heater.
[0012] The purpose of the invention is to provide a steam turbine
plant that can reduce differential thermal expansion of a steam
turbine by further effectively using heat in a plant, without
affecting efficiency and control of a heat source device, and
regardless of a presence or absence of steam generation by a steam
generating device.
[0013] To achieve the above purpose, a steam turbine plant of the
invention includes a heat source device that heats a low
temperature fluid by a heat source medium to obtain a high
temperature fluid, a steam generating device that generates steam
by heat exchange with the high temperature fluid obtained by the
heat source device, a steam turbine that is driven by the steam
generated by the steam generating device, a heating flow path that
is disposed on an outer surface of a casing of the steam turbine or
inside a member configuring the casing, a high temperature fluid
supply passage that is branched from a flow path of the high
temperature fluid in the steam generating device, is connected to
the heating flow path, and supplies the high temperature fluid to
the heating flow path, and a high temperature fluid flow rate
regulating device that regulates a flow rate of the high
temperature fluid flowing through the high temperature fluid supply
passage.
[0014] According to the invention, it is possible to reduce the
differential thermal expansion of the steam turbine by further
effectively using the heat in the plant, without affecting the
efficiency and control of the heat source device, and regardless of
the presence or absence of the steam generation by the steam
generating device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic diagram illustrating a configuration
of a steam turbine plant according to a first embodiment of the
invention.
[0016] FIG. 2 is a cross-sectional view in a turbine radial
direction illustrating a schematic structure of a heating flow path
of a casing of a steam turbine according to the first embodiment of
the invention.
[0017] FIG. 3 is a cross-sectional view in a turbine axial
direction illustrating a schematic structure of the heating flow
path of the casing of the steam turbine according to the first
embodiment of the invention.
[0018] FIG. 4 is a view for explaining a flow rate control of a
high temperature fluid to be supplied to the heating flow path
according to the first embodiment of the invention.
[0019] FIG. 5 is a view for explaining differential thermal
expansion between a rotor of the steam turbine and the casing
according to the first embodiment of the invention and the related
art.
[0020] FIG. 6 is a schematic diagram illustrating a configuration
of a steam turbine plant according to a second embodiment of the
invention.
[0021] FIG. 7 is a cross-sectional view in a turbine radial
direction illustrating a schematic structure of a heating flow path
and a cooling flow path of a casing of a steam turbine according to
the second embodiment of the invention.
[0022] FIG. 8 is a cross-sectional view in a turbine axial
direction illustrating a schematic structure of the heating flow
path and the cooling flow path of the casing of the steam turbine
according to the second embodiment of the invention.
[0023] FIG. 9 is a view for explaining a flow rate control of a low
temperature fluid to be supplied to the cooling flow path according
to the second embodiment of the invention.
[0024] FIG. 10 is a view for explaining temperature difference
between an upper half and a lower half of the casing of the steam
turbine according to the second embodiment of the invention and the
related art.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Control means for controlling the amount of heat input to a
steam turbine and a steam turbine plant having this means according
to a first embodiment of the invention will be described with
reference to drawings.
[0026] FIG. 1 is a schematic diagram illustrating a configuration
of the steam turbine plant according to the embodiment. In FIG. 1,
only configuration components and control circuits required for
describing the invention are illustrated. FIG. 2 is a
cross-sectional view in a turbine radial direction illustrating a
schematic structure of a heating flow path of a casing of a steam
turbine according to the embodiment, and FIG. 3 is a
cross-sectional view in a turbine axial direction. In FIG. 2,
drawings of a rotor, a moving blade, and a stationary blade are
omitted, and in FIG. 3, only an upper half side of a turbine is
illustrated.
[0027] The steam turbine plant of the embodiment is provided with a
heat source device 1, a steam generating device 2, a steam turbine
3, a generator 4, and a plant control device 5.
[0028] The heat source device 1 generates high temperature fluid by
heating low temperature fluid with a heat source medium, and is
adapted to supply the high temperature fluid to the steam
generating device 2. There is a gas turbine of a combined cycle
power plant as one concrete example of the heat source device 1,
using natural gas and kerosene as the heat source medium. There is
a furnace of a coal-fired power plant as another concrete example,
using coal as the heat source medium. There is a heat collector of
a solar thermal power plant as still another concrete example,
using sunlight as the heat source medium.
[0029] The steam generating device 2 has a flow path in which the
high temperature fluid supplied from the steam generating device 2
flows, and a plurality of heat exchangers (only one is conceptually
illustrated in FIG. 1) disposed in a flow direction in the flow
path. The steam generating device 2 generates steam from the water
supply by heat exchange with the high temperature fluid, and is
adapted to supply the steam to the steam turbine 3.
[0030] The steam turbine 3 is provided with a casing 32 that houses
a rotor 31 and the rotor 31, and a heat insulating material 33
disposed on the outside of the casing 32. A plurality of the moving
blades are disposed in an outer peripheral side of the rotor 31,
and a plurality of the stationary blades are disposed in an inner
peripheral side of the casing 32. The moving blades and the
stationary blades are alternately arranged in the turbine axial
direction. The steam turbine 3 is driven by the steam supplied from
the steam generating device 2. The generator 4 connected to the
steam turbine 3 is adapted to convert a driving force of the steam
turbine 3 to the power.
[0031] The plant control device 5 inputs a measurement value of
plant state quantity (specifically, for example, such as the
temperature of the high temperature fluid supplied from the heat
source device 1 to the steam generating device 2 and the
temperature of the steam supplied from the steam generating device
2 to the steam turbine 3), and calculates to output a command value
to the plant configuration components (specifically, for example,
such as a valve to adjust the flow rate of the heat source medium
supplying to the heat source device 1, and a valve to adjust the
flow rate of the steam supplying from the steam generating device 2
to the steam turbine 3), based on the measurement value.
[0032] Here, as one feature of the embodiment, a plurality (six in
the embodiment) of the heating flow paths 13 having layer shape are
disposed between the casing 32 and the heat insulating material 33
of the steam turbine 3 (in other words, on outer surface of the
casing 32). The heating flow path 13 is partitioned by a plurality
of partition plates 14 extending in the turbine axial direction.
The heating flow path 13 is configured so that the high temperature
fluid flows into one side end of the heating flow path 13, and
flows out from the other side end of the heating flow path 13 after
the heating of the casing 32 is finished.
[0033] As one feature of the embodiment, a high temperature fluid
supply passage 11 branched from the flow path of the high
temperature fluid in the steam generating device 2, and connected
to the heating flow path 13 is disposed. The high temperature fluid
supply passage 11 partially supplies the high temperature fluid
flowing into the steam generating device 2 to the heating flow path
13. A high temperature fluid flow rate regulating device 12
disposed in the high temperature fluid supply passage 11 is adapted
to adjust the flow rate of the high temperature fluid flowing
through the high temperature fluid supply passage 11, based on the
command value (described later). Specifically, the high temperature
fluid flow rate regulating device 12, for example, has means for
adjusting a cross-sectional area of the flow path, and means for
facilitating the flow to manipulate these means at the same time.
As the means for adjusting the cross-sectional area of the flow
path, for example, a partition plate or a valve is included. As the
means for facilitating the flow, a ventilator or a blower is
included. For example, the cross-sectional area of the flow path is
varied by rotating or moving the partition plate, while maintaining
the flow velocity by the ventilator constant. Therefore, the flow
rate of the high temperature fluid is adjusted. However, if the
sufficient flow velocity of the high temperature fluid can be
ensured, it may not have the means for facilitating the flow. In a
case of using the ventilator capable of regulating the flow rate,
it may not have the means for regulating the cross-sectional area
of the flow path.
[0034] As one feature of the embodiment, the plant control device 5
has a heating control circuit 101 that controls the high
temperature fluid flow rate regulating device 12. The heating
control circuit 101 inputs the measurement value of differential
thermal expansion between the rotor 31 and the casing 32, or
calculates the differential thermal expansion between the rotor 31
and the casing 32 by a known method of the heat transfer
engineering. For example, as illustrated in FIG. 4, a numerical
table or a formula that indicates a relationship such that the flow
rate of the high temperature fluid of the high temperature fluid
supply passage 11 is increased, as the differential thermal
expansion between the rotor 31 and the casing 32 is increased, is
previously stored. The flow rate of the high temperature fluid
supply passage 11 is calculated from the measurement value or a
calculated value of the differential thermal expansion, based on
the numerical table or the formula, and the command value
corresponding to the flow rate is calculated and outputs to the
high temperature fluid flow rate regulating device 12.
[0035] As illustrated in FIG. 4, an example of a method for
obtaining the relationship between the differential thermal
expansion between the rotor 31 and the casing 32 and the flow rate
of the high temperature fluid of the high temperature fluid supply
passage 11, performs a following calculation for each differential
thermal expansion between the rotor 31 and the casing 32 (in other
words, for each temperature difference). The required amount of
heat is calculated in order that the temperature of the casing 32
is to be equal to the temperature of the rotor 31 from the
temperature, mass, or specific heat of the rotor 31 and the casing
32, based on the known method of the heat transfer engineering. The
required flow rate of the high temperature fluid for supplying the
amount of heat is calculated from the amount of heat described
above, the temperature of the high temperature fluid of the high
temperature fluid supply passage 11, or thermal resistance between
the high temperature fluid and the casing 32, based on the known
method of the heat transfer engineering. In addition to this
method, it is possible to seek by trial and error by using a steam
turbine structure analysis tool created based on the known method
of the heat transfer engineering.
[0036] Next, the function and effect of the embodiment will be
described with compared to the related art. FIG. 5 is a view for
explaining differential thermal expansion between the rotor and the
casing of the steam turbine according to the embodiment and the
related art.
[0037] In the related art (that is, in a case where the high
temperature fluid supply passage 11, the high temperature fluid
flow rate regulating device 12, and the heating flow path 13 are
not disposed), at a time of starting the plant, since thermal
expansion of the rotor and thermal expansion of the casing of the
steam turbine occur as illustrated in FIG. 5, the differential
thermal expansion between the rotor and the casing is
increased.
[0038] Meanwhile, in the embodiment, at the time of starting the
plant, the high temperature fluid is supplied to the heating flow
path 13 of the casing 32 of the steam turbine 3 from the steam
generating device 2 via the high temperature fluid supply passage
11. Thereby, the casing 32 is heated, and thus the thermal
expansion of the casing 32 is facilitated, as illustrated in FIG.
5. As a result, the differential thermal expansion between the
rotor 31 and the casing 32 can be reduced.
[0039] In the embodiment, since the high temperature fluid
finishing a work is used in the heat source device 1, the fluid
does not affect the efficiency and control of the heat source
device 1. Changing the control circuit for controlling the heat
source device 1 is not required.
[0040] In the embodiment, since the high temperature fluid flowing
in the steam generating device 2 is partially used, regardless of a
presence or absence of the steam generation in the steam generating
device 2, the heat of the high temperature fluid can be used.
Therefore, from before, that is, from an earlier time to generate
the steam in the steam generating device 2, the casing 32 can be
heated. Since the high temperature fluid which is at a higher
temperature than the steam can be used, the casing 32 can be heated
at fast. Accordingly, the differential thermal expansion can be
reduced.
[0041] In the embodiment, the heat of the high temperature fluid
can be used only in a period in which the differential thermal
expansion between the rotor 31 and the casing 32 of the steam
turbine 3 occurs. Therefore, the plant can be operated without
lowering the efficiency in the rated load of the steam turbine
3.
[0042] In the embodiment, by effectively using the heat in the
plant, the amount of heat input to the steam turbine 3 is
controlled. Therefore, for example, unlike a case of disposing a
heater for heating the casing, an external power source for
securing the power of the heater is not necessary.
[0043] Control means for controlling the amount of heat input to a
steam turbine and a steam turbine plant having this means according
to the second embodiment of the invention will be described with
reference to drawings. Portions equivalent to that of the first
embodiment will be denoted by the same reference numerals, and a
description thereof will be omitted.
[0044] FIG. 6 is a schematic diagram illustrating a configuration
of a steam turbine plant according to the embodiment. In FIG. 6,
only configuration components and control circuits required for
describing the invention are illustrated. FIG. 7 is a
cross-sectional view in a turbine radial direction illustrating a
schematic structure of a heating flow path and a cooling flow path
of a casing of a steam turbine according to the embodiment, FIG. 8
is a cross-sectional view in a turbine axial direction. In FIG. 7,
drawings of the rotor, the moving blade, and the stationary blade
are omitted.
[0045] In the embodiment, a plurality (five in the embodiment) of
the heating flow paths 13 having layer shape, and one cooling flow
path 23 having layer shape are disposed between the casing 32 and
the heat insulating material 33 of the steam turbine 3 (in other
words, on outer surface of the casing 32). The heating flow path 13
and the cooling flow path 23 are partitioned by a plurality of
partition plates 14 extending in the turbine axial direction.
[0046] The cooling flow path 23 is disposed on a portion (portion
of a lower half of the casing 32 in the embodiment) to be a
relatively high temperature at the time of starting the plant. The
heating flow paths 13 are disposed on a portion (remaining portion
of a lower half and an upper half of the casing 32 in the
embodiment) to be a relatively low temperature at the time of
starting the plant. The portion to be the relatively high
temperature at the time of starting the plant, for example, is a
portion where piping in which the steam is supplied is installed.
The cooling flow path 23 is configured so that the low temperature
fluid flows into one end of the cooling flow path 23, and flows out
from the other end of the cooling flow path 23, after cooling of a
portion of the lower half of the casing 32 is finished. The heating
flow path 13 is configured so that the high temperature fluid flows
into one side end of the heating flow path 13, and flows out from
the other end of the heating flow path 13, after heating of the
remaining portion of the lower half and the upper half of the
casing 32 is finished.
[0047] In the embodiment, a low temperature fluid supply passage 21
that supplies the low temperature fluid to the cooling flow path 23
is disposed. Here, the low temperature fluid supplied to the
cooling flow path 23 is at a lower temperature than the steam
supplied to the steam turbine 3 from the steam generating device 2.
As the low temperature fluid, for example, air in the atmosphere,
fluid obtained by mixing the air and a portion of the high
temperature fluid flowing in the steam generating device 2, or the
like is included. A low temperature fluid flow rate regulating
device 22 disposed in the low temperature fluid supply passage 21
is adapted to regulate the flow rate of the low temperature fluid
flowing in the low temperature fluid supply passage 21, based on
the command value described later. The low temperature fluid flow
rate regulating device 22 may be the same configuration as that of
the high temperature fluid flow rate regulating device 12.
[0048] In the embodiment, the plant control device 5 has a cooling
control circuit 201 that controls the low temperature fluid flow
rate regulating device 22. The cooling control circuit 201 inputs
the measurement value of the temperature difference between the
lower half (that is, a portion where the cooling flow path 23 is
disposed) and the upper half (that is, a portion where the heating
flow path 13 is disposed) of the casing 32, or calculates the
temperature difference between the lower half and the upper half of
the casing 32 by the known method of the heat transfer engineering.
For example, as illustrated in FIG. 9, a numerical table or a
formula that indicates a relationship such that the flow rate of
the low temperature fluid of the low temperature fluid supply
passage 21 is increased, as the temperature difference between the
lower half and the upper half of the casing 32 is increased, is
previously stored. The flow rate of the low temperature fluid
supply passage 21 is calculated from the measurement value or a
calculated value of the temperature difference, based on the
numerical table or the formula, and the command value corresponding
to the flow rate is calculated and outputs to the low temperature
fluid flow rate regulating device 22.
[0049] As illustrated in FIG. 9, an example of a method for
obtaining the relationship between the temperature difference
between the lower half and the upper half of the casing 32 and the
flow rate of the low temperature fluid of the low temperature fluid
supply passage 21, performs a following calculation for each
temperature difference between the lower half and the upper half of
the casing 32. The amount of heat required for the unit change in
temperature of the lower half of the casing 32 is calculated from
mass, or specific heat of the lower half of the casing 32, based on
the known method of the heat transfer engineering. By integrating
the temperature difference between the lower half and the upper
half of the casing 32 with respect to the amount of heat required
for the unit temperature change of the lower half of the casing 32,
the required amount of heat (amount of cooling) in order that the
temperature of the lower half of the casing 32 is to be equal to
the temperature of the upper half is calculated. The required flow
rate of the low temperature fluid for supplying the amount of heat
is calculated from the amount of heat described above, the
temperature of the low temperature fluid of the low temperature
fluid supply passage 21, or thermal resistance between the low
temperature fluid and the casing 32, based on the known method of
the heat transfer engineering. In addition to this method, it is
possible to seek by trial and error by using a steam turbine
structure analysis tool created based on the known method of the
heat transfer engineering.
[0050] In the embodiment configured as described above, at the time
of starting the plant, the high temperature fluid is supplied to
the heating flow path 13 of the casing 32 of the steam turbine 3
from the steam generating device 2 via the high temperature fluid
supply passage 11. Thereby, at the time of starting the plant, the
thermal expansion of the portion to be relatively low temperature
is facilitated by heating the portion thereof. As a result, similar
to the first embodiment, the differential thermal expansion between
the rotor 31 and the casing 32 can be reduced.
[0051] In the embodiment, thermal deformation of the casing 32 can
be reduced. Such as the function and effect will be described with
compared to the related art. FIG. 10 is a view for explaining
temperature difference between the lower half and the upper half of
the casing of the steam turbine according to the embodiment and the
related art.
[0052] In the related art (that is, in a case where the low
temperature fluid supply passage 21, the low temperature fluid flow
rate regulating device 22, and the cooling flow path 23 are not
disposed), at the time of starting the plant, since temperature
rise of the lower half and temperature rise of the upper half occur
as illustrated in FIG. 10, the temperature difference between the
lower half and the upper half is increased.
[0053] Meanwhile, in the embodiment, at the time of starting the
plant, the low temperature fluid is supplied to the cooling flow
path 23 of the casing 32 of the steam turbine 3 via the low
temperature fluid supply passage 21. Thereby, the lower half of the
casing 32 is cooled, and thus the temperature rise of the lower
half of the casing 32 is suppressed, as illustrated in FIG. 10. As
a result, the temperature difference between the lower half and the
upper half of the casing 32 can be reduced, and the thermal
deformation of the casing 32 can be reduced.
[0054] Although a case in which the cooling flow path 23 is
disposed on the portion of the lower half of the casing 32 as the
portion to be the relatively low temperature at the time of
starting the plant is described as an example in the second
embodiment, without being limited thereto, arrangement and number
of the cooling flow path 23 may be determined by the analysis of
the empirical knowledge or the known method of the heat transfer
engineering. That is, the cooling flow path may be disposed on the
upper half side of the casing 32 as the portion to be relatively
low temperature, at the time of starting the plant. In addition, at
the time of starting the plant, if the portion to be relatively low
temperature and the portion to be the relatively high temperature
is replaced, the cooling flow path and the heating flow path may be
replaced. In such a case, it is possible to obtain the same effect
as described above.
[0055] Although a case in which the heating flow path 13 is
disposed on the outer surface of the casing 32 of the steam turbine
3 is described as an example in the first embodiment, and a case in
which the heating flow path 13 and the cooling flow path 23 are
disposed on the outer surface of the casing 32 of the steam turbine
3 is described as an example in the second embodiment, it is not
limited thereto. That is, for example, if the casing of the steam
turbine has a dual structure, the heating flow path may be disposed
between the inner casing and the outer casing and the cooling flow
path may be disposed between the inner casing and the outer casing.
In such a case, it is possible to obtain the same effect as
described above.
* * * * *