U.S. patent application number 12/083257 was filed with the patent office on 2009-11-26 for method for warming-up a steam turbine.
Invention is credited to Edwin Gobrecht, Karsten Peters.
Application Number | 20090288415 12/083257 |
Document ID | / |
Family ID | 36282973 |
Filed Date | 2009-11-26 |
United States Patent
Application |
20090288415 |
Kind Code |
A1 |
Gobrecht; Edwin ; et
al. |
November 26, 2009 |
Method for Warming-Up a Steam Turbine
Abstract
There is described a method for heating a steam turbine
comprising a medium-pressure turbine section and/or a low-pressure
turbine section, the discharge end of the medium-pressure turbine
section being provided with a catchment device. Steam penetrating
the medium-pressure turbine section during a starting process is
retained at an outlet by means of a catchment device in such a way
that the pressure of the steam increases in the medium-pressure
turbine section. The steam that is discharged from the
medium-pressure turbine section is retained, thus increasing the
pressure and the temperature of the steam. Heat transfer from the
steam to the thick-walled parts located on the medium pressure
turbine section and the shaft of the medium-pressure turbine
section is augmented, thus reducing the starting time of the steam
turbine.
Inventors: |
Gobrecht; Edwin; (Ratingen,
DE) ; Peters; Karsten; (Wesel, DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
36282973 |
Appl. No.: |
12/083257 |
Filed: |
October 11, 2006 |
PCT Filed: |
October 11, 2006 |
PCT NO: |
PCT/EP2006/067254 |
371 Date: |
April 8, 2008 |
Current U.S.
Class: |
60/646 ;
60/659 |
Current CPC
Class: |
Y02T 50/60 20130101;
F01D 25/10 20130101; F01K 7/165 20130101; Y02T 50/675 20130101;
F01K 13/02 20130101 |
Class at
Publication: |
60/646 ;
60/659 |
International
Class: |
F01K 13/02 20060101
F01K013/02; F01K 3/08 20060101 F01K003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2005 |
EP |
05022279.3 |
Claims
1.-8. (canceled)
9. A method for warming-up a steam turbine having an
intermediate-pressure turbine section, comprising: providing a
intermediate-pressure turbine section, wherein the
intermediate-pressure turbine section has an accumulating device on
an outlet side; and accumulating steam which flows through the
intermediate-pressure turbine section during a starting process at
the outlet, based upon the accumulating device such that the
pressure of the steam in the intermediate-pressure turbine section
is increased, such that a saturation temperature of the steam is
increased.
10. The method as claimed in claim 9, wherein the accumulating
device is arranged in an overflow line.
11. The method as claimed in claim 9, wherein the accumulating is
controlled.
12. The method as claimed in claim 10, wherein the accumulating is
controlled.
13. The method as claimed in claim 9, wherein the accumulating
device has a pivotable flap.
14. The method as claimed in claim 10, wherein the accumulating
device has a pivotable flap.
15. The method as claimed in claim 11, wherein the accumulating
device has a pivotable flap.
16. The method as claimed in claim 12, wherein the accumulating
device has a pivotable flap.
17. The method as claimed in one of claim 9, further comprising
accumulating the steam on the outlet side to values of between 3
and 5 bar, and between 130.degree. C. and 150.degree. C.
18. The method as claimed in one of claim 10, further comprising
accumulating the steam on the outlet side to values of between 3
and 5 bar, and between 130.degree. C. and 150.degree. C.
19. The method as claimed in one of claim 11, further comprising
accumulating the steam on the outlet side to values of between 3
and 5 bar, and between 130.degree. C. and 150.degree. C.
20. The method as claimed in one of claim 12, further comprising
accumulating the steam on the outlet side to values of between 3
and 5 bar, and between 130.degree. C. and 150.degree. C.
21. A steam turbine plant, comprising: an intermediate-pressure
turbine section; and an accumulating device arranged on an outlet
side of the intermediate-pressure turbine section.
22. The steam turbine plant as claimed in claim 21, wherein the
accumulating device has a pivotable flap.
23. The steam turbine plant as claimed in claim 21, wherein the
accumulating device is arranged in an overflow line.
24. The steam turbine plant as claimed in claim 22, wherein the
accumulating device is arranged in an overflow line.
25. The steam turbine plant as claimed in claim 21, wherein the
outlet side withstands steam with a pressure between 3 and 5 bar,
and a temperature between 130.degree. C. and 150.degree. C.
26. The steam turbine plant as claimed in claim 22, wherein the
outlet side withstands steam with a pressure between 3 and 5 bar,
and a temperature between 130.degree. C. and 150.degree. C.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2006/067254, filed Oct. 11, 2006 and claims
the benefit thereof. The International Application claims the
benefits of European Patent Office application No. 05022279.3 EP
filed Oct. 12, 2005, both of the applications are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a method for warming-up a steam
turbine which comprises an intermediate-pressure turbine section
and/or low-pressure turbine section, wherein the
intermediate-pressure turbine section on the outlet side has an
accumulating device.
BACKGROUND OF INVENTION
[0003] A steam turbine is also referred to as a turbomachine. Water
turbines, steam and gas turbines, wind wheels, centrifugal pumps
and centrifugal compressors and also propellers, are brought
together under the collective term of turbomachines. Common to all
these machines is that they serve for the purpose of extracting
energy from a fluid in order to drive another machine with it, or
vice versa to supply energy to a fluid in order to increase its
pressure.
[0004] A turbine section which on the inlet side is exposed to
admission of superheated steam, which can have temperatures of up
to 620.degree. C. and a pressure of up to 300 bar, is understood by
a high-pressure turbine section in this application. The
aforementioned temperature and pressure specifications are only
reference values. Turbine sections, which are designed for higher
temperatures and for higher pressures, can also be referred to as
high-pressure turbine sections. An intermediate-pressure turbine
section is customarily exposed to admission of superheated steam
which has a temperature of 600.degree. C. and a pressure of about
140 bar. A low-pressure turbine section is customarily exposed to
admission of steam which issues from the intermediate-pressure
turbine section. The steam which issues from the low-pressure
turbine section is finally collected in a condenser and converted
into water again. As a rule, the steam which issues from the
high-pressure turbine section is heated in a reheater and is fed
into the intermediate-pressure turbine section.
SUMMARY OF INVENTION
[0005] In local power supply, it is of great importance that the
steam turbines which are formed for driving the generators are able
to be run up to the nominal speeds as quickly as possible. The
nominal speeds are at 50 or 60 Hz. However, other nominal speeds
are also known.
[0006] In the course of this, it is problematical that the shafts
and other thick-walled components in steam turbines have to be
prewarmed in a controlled manner before loading with full operating
parameters in order to prevent impermissible stresses in the
components.
[0007] The turbine shafts of intermediate-pressure turbine sections
are customarily run up against a vacuum. That means, a
comparatively low pressure prevails on the outlet side of the
intermediate-pressure turbine section. For this reason, the
saturation temperature and the density of the throughflowing steam
in the intermediate-pressure turbine section is low. Consequently,
the heat yield to the shaft by means of the steam is low, which
leads to a delay when prewarming an intermediate-pressure turbine
section. Consequently, the starting time of the steam turbine is
altogether extended. A starting time which is too long is
considered to be an impairment.
[0008] It is an object of the invention, therefore, to disclose a
method with which a steam turbine can be quickly warmed up.
[0009] The object is achieved by means of a method for warming-up a
steam turbine which comprises an intermediate-pressure turbine
section and/or low-pressure turbine section, wherein the
intermediate-pressure turbine section on the outlet side has an
accumulating device, wherein during a starting process steam which
flows through the intermediate-pressure turbine section is
accumulated at an outlet by means of the accumulating device in
such a way that the pressure of the steam in the
intermediate-pressure turbine section is increased in such a way
that the saturation temperature of the steam is increased.
[0010] The invention is based inter alia upon the aspect that by
means of a controlled accumulating of the steam flow at the outlet
of the intermediate-pressure turbine section during the starting
process of the steam turbine, the pressure is increased. For
example, by means of closing a flap the pressure at the outlet of
the intermediate-pressure turbine section is increased. Increasing
the pressure leads to the saturation temperature of the steam being
increased. The heat transfer values are particularly high in the
case of saturated steam. These heat transfer values are higher than
in the case of convective warming-up. Therefore, the temperature of
the steam in the case of saturation is decisive for the heat yield
to the shaft. For example, the temperature without the accumulating
according to the invention is at about80.degree. C. and about 0.5
bar. By means of accumulating the outlet side steam of the
intermediate-pressure turbine section at the accumulating device,
for example to 4 bar, a saturation temperature of the steam of
144.degree. C. ensues as a result of this. The heat transfer to the
shaft which is arranged in the steam turbine is consequently
increased which results in the shaft being warmed-up comparatively
quickly.
[0011] Furthermore, due to the higher steam density, a subsequent
convective superheating of an intermediate-pressure turbine section
shaft is also accelerated.
[0012] By means of this measure according to the invention, with
the heat being able to be introduced quicker into an
intermediate-pressure turbine section shaft, the starting process
of a steam turbine can be shortened during a cold start by up to an
hour. In an advantageous development, the accumulating device is
arranged in the overflow line. The overflow line in this case is a
line which fluidically connects the outlet of the
intermediate-pressure turbine section to the inlet of a
low-pressure turbine section.
[0013] By means of this measure, it is comparatively simple to
increase the pressure on the outlet side of an
intermediate-pressure turbine section.
[0014] In a further advantageous development, the accumulating
device is formed with controllability.
[0015] Consequently, the warming-up process of the steam turbine
can be controlled. For example, a steam mass flow, which flows
discontinuously into the intermediate-pressure turbine section,
could be varied by means of the controllable accumulating device in
such a way that the heat yield to the thick-walled components of
the intermediate-pressure turbine section occurs at the same
time.
[0016] The temperature, the pressure and/or the steam mass flow
could be used as input values for controlling the accumulating
device.
[0017] In a further advantageous development, the accumulating
device is formed as a pivotable flap. The forming of a pivotable
flap is a comparatively inexpensive measure with which the desired
effect, specifically the accumulating of steam, is achieved.
[0018] In a further advantageous development, the steam on the
outlet side of the intermediate-pressure turbine section is
accumulated to pressure values of between 3 and 5 bar, and
temperature values of between 130.degree. C. and 150.degree. C.
[0019] It has been shown that with these pressure and temperature
values the heat yield of the steam to the intermediate-pressure
turbine section shaft is particularly high.
BRIEF DESCRIPTION OF THE DRAWING
[0020] Exemplary embodiments of the invention are subsequently
described in more detail with reference to the drawings. In this
case, components which are provided with the same designations have
the same principle of operation.
[0021] In this case, in the drawing:
[0022] FIG. 1 shows a schematic representation of an
intermediate-pressure turbine section and a low-pressure turbine
section.
DETAILED DESCRIPTION OF INVENTION
[0023] In FIG. 1, a schematic representation of a steam turbine 8
is shown. A steam turbine can comprise a high-pressure turbine
section, intermediate-pressure turbine section and/or a
low-pressure turbine section. The steam turbine which is shown in
the figure comprises an intermediate-pressure and a low-pressure
turbine section. As a rule, live steam flows into a high-pressure
turbine section, which is not shown in the figure, and is expanded
there, and cooled down to a lower temperature. This expanded and
cooled-down steam is heated to a higher temperature in a reheater,
which is not shown in more detail in FIG. 1, and then fed into an
intermediate-pressure turbine section 2 via a line 1. The steam
which flows into the intermediate-pressure turbine section 2
expands, wherein the pressure and the temperature of the steam drop
in the process.
[0024] On the outlet side of the intermediate-pressure turbine
section 2, the expanded steam flows from an outlet 3 via an
overflow line 4 into an inlet 5 of a low-pressure turbine section
6. The intermediate-pressure turbine section 2 and low-pressure
turbine section 6, which are shown in FIG. 1, are to be seen as
part of a steam turbine. For the sake of clarity, the high-pressure
turbine section, the reheater, the condenser and various units,
such as a pump, are not shown in more detail.
[0025] An accumulating device 7 is arranged in the overflow line 4.
The accumulating device 7 can be formed with controllability and/or
as a pivotable flap. During a starting process, the accumulating
device 7 is operated in such a way that the steam which issues at
the outlet 3 is accumulated in front of the control flap, as a
result of which the pressure of the steam is increased.
Consequently, the saturation temperature of the steam is increased,
which leads to an increase of the temperature transfer values of
the steam to the intermediate-pressure turbine shaft of the
intermediate-pressure turbine section 2. The intermediate-pressure
turbine shaft is not shown in more detail.
[0026] It has been shown that the steam on the outlet side should
be accumulated to values of between 3 and 5 bar, and 130.degree. C.
and 150.degree. C., in order to maintain good heat transfer
values.
[0027] The starting process of a steam turbine is shortened by
about one hour as a result.
* * * * *