U.S. patent application number 12/240015 was filed with the patent office on 2009-02-05 for steam turbine installation and associated operating method.
Invention is credited to Ralf Greim, Timothy Stephen Rice.
Application Number | 20090031726 12/240015 |
Document ID | / |
Family ID | 36645997 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090031726 |
Kind Code |
A1 |
Greim; Ralf ; et
al. |
February 5, 2009 |
STEAM TURBINE INSTALLATION AND ASSOCIATED OPERATING METHOD
Abstract
A steam turbine installation (1), especially for electricity
generation, includes a steam path (2) in which a steam generator
(4) and a steam turbine (3) are arranged. In order to reduce the
risk of erosion for components which are arranged in the steam path
(2), for example blades of the steam turbine (3), an inertial
separator (6) is arranged in the steam path (2) between the steam
generator (4) and the steam turbine (3).
Inventors: |
Greim; Ralf; (Birmenstorf,
CH) ; Rice; Timothy Stephen; (Rugby, GB) |
Correspondence
Address: |
CERMAK KENEALY & VAIDYA LLP
515 E. BRADDOCK RD, SUITE B
ALEXANDRIA
VA
22314
US
|
Family ID: |
36645997 |
Appl. No.: |
12/240015 |
Filed: |
September 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/EP2007/050730 |
Jan 25, 2007 |
|
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12240015 |
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Current U.S.
Class: |
60/657 ;
60/646 |
Current CPC
Class: |
B04C 5/04 20130101; B04C
5/12 20130101; F01D 25/32 20130101; B04C 5/081 20130101; F05D
2220/31 20130101; F01K 21/06 20130101 |
Class at
Publication: |
60/657 ;
60/646 |
International
Class: |
F01K 21/06 20060101
F01K021/06; F01K 13/00 20060101 F01K013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2006 |
CH |
00531/06 |
Claims
1. A steam turbine installation useful for electricity generation
comprising: a steam path; a steam generator and a steam turbine
arranged in the steam path, the steam turbine downstream of the
steam generator; and at least one inertial separator arranged in
the steam path between the steam generator and the steam
turbine.
2. The steam turbine installation as claimed in claim 1, wherein
the inertial separator comprises a cyclone separator.
3. The steam turbine installation as claimed in claim 2, comprising
at least one the following: the cyclone separator is arranged in an
upright position and has a vertical longitudinal center axis; a
steam inlet connected tangentially to the cyclone separator; a
steam outlet connected axially centrally or tangentially to the
cyclone separator; the cyclone separator includes a cylinder
section with a lower end region, a steam inlet connected to the
cyclone separator lower end region; the cyclone separator includes
a cylinder section with an upper end region, a steam outlet
connected to the cyclone separator upper end region; the cyclone
separator includes a cylinder section with a bottom, and a
downwards tapering cone section which adjoins the cylinder section
at the bottom.
4. The steam turbine installation as claimed in claim 2, comprising
at least one of the following: the cyclone separator has a globular
housing; the cyclone separator has a housing, and comprising a
steam inlet connected tangentially to the housing; the cyclone
separator has a housing, and comprising a steam inlet connected to
the housing in an equatorial plane; the cyclone separator has a
housing with a longitudinal center axis, and comprising a steam
outlet connected to the housing coaxially to the longitudinal
center axis of the housing; the cyclone separator has a steam
inlet, a steam outlet, and a longitudinal center axis associated
with the steam outlet is perpendicular to an equatorial plane
associated with the steam inlet; the cyclone separator has a steam
outlet, a longitudinal center axis, and an outlet opening for
removing contaminants from the housing which are deposited in the
housing arranged on the housing coaxially to the longitudinal
center axis of the housing; the cyclone separator has a steam
outlet, a longitudinal center axis, and a longitudinal center axis
associated with the outlet opening arranged coaxially to a
longitudinal center axis associated with the steam outlet; the
cyclone separator has a steam inlet, a steam outlet opening, and a
longitudinal center axis associated with the outlet opening
perpendicular to an equatorial plane which is associated with the
steam inlet; and the cyclone separator has a steam inlet, a steam
outlet opening, and a housing arranged in the upright position so
that an equatorial plane associated with the steam inlet extends
essentially horizontally, and/or so that a longitudinal center axis
associated with the steam outlet extends vertically, and/or so that
a longitudinal center axis associated with the outlet opening
extends vertically.
5. The steam turbine installation as claimed in claim 1, comprising
at least one of the following: the inertial separator is configured
and arranged to be operated at a steam pressure of about 250 bar to
about 350 bar, and/or at a steam temperature of about 620.degree.
C. to about 720.degree. C.; the inertial separator is configured
and arranged to separate out from the steam particles with a grain
size of less than 0.5 mm; and the inertial separator is configured
and arranged to separate out oxide particles.
6. The steam turbine installation as claimed in claim 5, wherein
the inertial separator is configured and arranged to separate out
from the steam particles with a grain size of less than 0.1 mm.
7. The steam turbine installation as claimed in claim 5, wherein
the oxide particles comprises magnetite or spinel.
8. A method for operating a steam turbine installation for
electricity generation, the method comprising: guiding steam from a
steam generator to a steam turbine; and extracting from the steam
particles which are entrained upstream of the steam turbine.
9. The method as claimed in claim 8, wherein extracting comprises
separating out particles from the steam with inertia forces.
Description
[0001] This application is a Continuation of, and claims priority
under 35 U.S.C. .sctn. 120 to, International application no.
PCT/EP2007/050730, filed 25 Jan. 2007, and claims priority
therethrough under 35 U.S.C. .sctn..sctn. 119, 365 to Swiss
application no. 00531/06, filed 31 Mar. 2006, the entireties of
which are incorporated by reference herein.
BACKGROUND
[0002] 1. Field of Endeavor
[0003] The invention relates to a steam turbine installation,
especially for electricity generation.
[0004] The invention also relates to a method for operating such a
steam turbine installation. Furthermore, the invention relates to a
use of an inertial separator.
[0005] 2. Brief Description of the Related Art
[0006] A combined gas turbine-steam power plant for electricity
generation is known from CH 653 097 A5. Such a combined cycle plant
includes, on the one hand, a gas turbine with an associated
compressor and an associated combustion chamber, and also, on the
other hand, a steam turbine with an associated steam generator. In
this case, the steam generator is heated with the hot exhaust gases
of the gas turbine.
[0007] In the case of the known combined cycle plant, the
combustion chamber is equipped with a fluidized bed. The exhaust
gases, or flue gases, which are created during operation are laden
with particles. In order to avoid entry of these particles into the
gas turbine, a plurality of cyclone separators are arranged in the
exhaust gas path upstream of the gas turbine.
[0008] A gas turbine installation is known from DE 198 34 376 A1,
in which stator blades are cooled with a cooling gas. In order to
separate out dust from the cooling gas, an axial cyclone is
arranged in the cooling gas path upstream of the stator blades
which are to be cooled.
[0009] With modern steam turbine installations, there is the trend
to increase the steam temperature and the steam pressure at the
inlet of the steam turbine in order to achieve higher levels of
efficiency as a result. With inlet temperatures of 580.degree. C.
to 600.degree. C., these steam turbines no longer operate
hypercritically or supercritically, but already
ultra-supercritically. Newer steam turbine installations tend
towards even higher inlet temperatures of 620.degree. C. to
650.degree. C. For future installations, even inlet temperatures of
700.degree. C. to 720.degree. C. are envisaged. It has been shown
that at these high steam temperatures, the oxidation of the
steam-conducting components, for example of the steam generator,
increases superproportionally. As a result of this, oxide particles
are created which become detached and are entrained by the steam
flow. The particles thus get into the steam turbine, but, as a
result of inertia, cannot follow the deflections of the steam flow
along the blades, as a result of which they impinge upon stator
blades and rotor blades. With the prevailing high velocities, it
leads to erosion phenomena on the blades. Such erosion phenomena
have a negative effect on the aerodynamics of the blades which
leads to a reduction of the efficiency of the steam turbine.
SUMMARY
[0010] The invention attempts to provide a remedy for this. One of
numerous aspects of the present invention deals with the problem of
showing a method for a steam turbine installation of the type
mentioned in the introduction, which especially reduces the risk of
erosion of the blades of the steam turbine as a result of oxide
particles.
[0011] Another aspect of the present invention is based on the
general idea of removing the entrained particles from the steam
flow in the steam path upstream of the steam turbine which leads
from the steam generator to the steam turbine, specifically
preferably by an inertial separator.
[0012] The use of an inertial separator, which in particular can be
designed as a cyclone separator, is a comparatively inexpensively
realizable measure which is characterized by a comparatively low
pressure loss compared with the use of conventional filters.
Furthermore, the use of an inertial separator is considerably more
cost-effective than the use of high-purity water for reducing the
oxidation effect of the steam, or than the use of especially
high-value materials in the region of the steam generator for
increasing the oxidation-resistance of these components, or than
the use of especially high-value alloys or coatings or surface
treatments of the blades for improving the erosion-resistance of
the blades. In comparison to these alternatives, the inertial
separator is therefore characterized by an extremely low pressure
loss and also by an inexpensive realizability. An inertial
separator is characterized in that a flow deflection is forced
within it, which the entrained particles cannot follow on account
of their greater mass. Instead of this, the particles impinge upon
corresponding obstacles, as a result of which they are additionally
braked.
[0013] Further important features and advantages of the present
invention result from the drawings and from the associated figure
description with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A preferred exemplary embodiment of the invention is shown
in the drawings and is explained in more detail in the subsequent
description, wherein like designations refer to the same, or
similar, or functionally the same components. In the drawing,
schematically in each case,
[0015] FIG. 1 shows a much simplified, circuit diagram-like
schematic representation of a steam turbine installation,
[0016] FIG. 2 shows a partially sectioned simplified side view of
an inertial separator, and
[0017] FIG. 3 shows a partially sectioned perspective view of
another inertial separator.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0018] According to FIG. 1, a steam turbine installation 1
exemplifying principles of the invention includes a steam path 2,
in which a steam turbine 3 and a steam generator 4 are arranged. In
this case, the steam turbine 3 is located downstream of the steam
generator 4 and for example can drive a generator 5 so that the
steam turbine installation 1 preferably serves for electricity
generation. The steam turbine installation 1 can be a part of a
combined cycle plant, that is to say a combined gas turbine-steam
power plant. In particular, the steam generator 4 can then be
heated with hot exhaust gases of the gas turbine. In principle,
however, the heating of the steam generator 4 is designed in any
desired manner.
[0019] According to an exemplary embodiment of the invention, an
inertial separator 6 is arranged in the steam path 2 downstream of
the steam generator 4 and upstream of the steam turbine 3. The
inertial separator 6 serves for separating out particles, that is
to say as a rule solid bodies, which are entrained in the steam
flow, which is carried out by means of inertia forces. The
separated-out particles can be extracted from the inertial
separator 6 in accordance with an arrow 7.
[0020] In steam turbine installations 1 with a plurality of
passages through the steam generator 4, so-called reheating, as are
customary nowadays typically both upstream of the high-pressure
turbine cylinder and of the intermediate-pressure turbine cylinder,
such an inertial separator can be associated with each passage. In
principle, each steam outlet from the steam generator 4 can be
equipped with such an inertial separator 6.
[0021] In accordance with FIGS. 2 and 3, the inertial separator 6
can preferably be designed as a cyclone separator which is
characterized in that the steam flow, which is represented by
arrows 8 in FIG. 2, rotates around a longitudinal center axis 9 of
the inertial separator 6. The cyclone separator is subsequently
also designated with 6. Other constructional forms, such as
electrostatic filters, are also possible so that the cyclone
separator 6 which is mentioned here is quoted purely exemplarily
and without limitation of the generality.
[0022] In the case of the embodiment which is shown in FIG. 2, the
cyclone separator 6 in the installed state is preferably arranged
in an upright position, as a result of which its longitudinal
center axis 9 extends essentially vertically. The cyclone separator
6 has two sections in the vertical direction, that is to say an
upper cylinder section 10 and a lower cone section 11. The cone
section 11 adjoins the cylinder section 10 at the bottom and tapers
as distance increases from the cylinder section 10, that is to say
downwards.
[0023] The cyclone separator 6 is integrated into the steam path 2
via a steam inlet 12 and a steam outlet 13. In the case of the
preferred embodiment which is shown here, the steam inlet 12 is
connected tangentially to the cyclone separator 6 or to its
cylinder section 10. As a result of this, the desired swirled flow
with regard to the longitudinal center axis 9 is already forced
during inflow into the cyclone separator 6. Such a swirled flow
creates strong centrifugal forces. Entrained particles are thrown
against the wall of the cyclone separator 6 on account of their
increased mass inertia, as a result of which the particles for one
thing can be sharply braked and for another thing can also be
broken up. The braking of the particles leads to these being able
to fall more easily downwards into the cone section 11 as a result
of gravity force. The breaking down of the particles has the
advantage that particles, which despite the intense separating
effect of the cyclone separator 6 leave the cyclone separator 6
again with the steam flow 8, represent only a reduced risk of
erosion in the steam turbine 3 for its blades.
[0024] As a result of the central swirl in the cyclone separator 6,
a centrifugal field is created in this, in which particles with
greater mass or greater specific weight are carried outwards. On
the outside, the wall contact then takes place with the
aforementioned consequences. In order to improve the breaking-down
effect when the particles impinge upon the wall of the cyclone
separator 6, the wall can be correspondingly designed. Furthermore,
the wall of the cyclone separator 6 can preferably be designed
specifically in the cylinder section 10 so that particles, which
move along the wall, cannot reach the steam outlet 13. For example,
the wall contains radially inwards projecting annular obstacles,
which are not shown. It is optionally or alternatively also
possible to electrostatically or electrodynamically charge the
respective wall which also makes it possible to "catch" particles
on the wall.
[0025] The cone section 11 serves as a collecting vessel for
separated particles. The separated particles can be extracted from
the cone section 11 in accordance with the arrow 7. This is
basically possible during the operation of the steam turbine
installation 1, since the steam flow operates with relatively high
pressures. By means of cyclic opening of a corresponding blow-off
valve, which is not shown here, which controls an outlet opening 14
of the cone section 11, the deposited particles can be discharged.
It is also possible to utilize downtimes of the steam turbine
installation 1 for removing the separated particles from the cone
section 11.
[0026] In the case of the embodiment which is shown here, the steam
outlet 13 is connected tangentially to the cyclone separator 6 or
to its cylinder section 10. This tangential connection, which
moreover is oriented in the rotational direction of the swirled
flow, reduces the throughflow resistance or the pressure drop when
exposing the cyclone separator 6 to throughflow. So that the
entrained particles cannot flow through the cyclone separator 6
unhindered, the two tangentially arranged connections, that is to
say steam inlet 12 and steam outlet 13, are arranged in a manner in
which they are at a distance from each other in the axial
direction. In this case, the arrangement which is shown here is
preferred, in which the steam inlet 12 is arranged in a lower end
region of the cylinder section 10, whereas the steam outlet 13 is
arranged in an upper end region of the cylinder section 10. In
order to reach the upper end region from the lower end region the
entrained particles would have to migrate upwards against gravity
force, which as a rule is not the case.
[0027] Unlike the embodiment which is shown, it is also possible in
principle to again arrange the steam outlet 13 tangentially but in
the opposite direction with regard to the rotational direction.
Similarly, the steam outlet 13 can be radially oriented with regard
to the longitudinal center axis 9. Furthermore, it is possible in
principle to arrange the steam outlet 13 axially and centrally with
regard to the longitudinal center axis 9. The last-named variant in
this case has the greatest separating effect.
[0028] The inertial separator 6 is adapted to the particular
operating conditions of the steam turbine installation 1. For this
purpose, the inertial separator 6 is preferably designed so that it
can operate at a steam pressure of between 250 bar and 350 bar.
Furthermore, the inertial separator 6 is designed for steam
temperatures in the range of 620.degree. C. to 720.degree. C. The
dimensioning of the inertial separator 6 for example is selected so
that as a result a steam quantity which is required for generating
a steam turbine output of about 1000 MW can to a greater or lesser
extent be cleaned of particles. For example, the inertial separator
6 is designed so that particles with a grain size of between 0.1 mm
and 0.5 mm can be separated out from the steam. The material
selection for the production of the inertial separator 6 is
expediently to be selected so that it is suitable for separating
out oxide particles such as magnetite or spinel. Furthermore, the
inertial separator 6 should have a service life of at least 50 000
h, but preferably 100 000 h to 200 000 h.
[0029] According to FIG. 3, the inertial separator 6, which is
designed as a cyclone separator 6, in another embodiment can have a
globular or spherical housing 15 which can be particularly simply
designed in an especially pressure-stable manner. The steam inlet
12 can also be connected tangentially to the housing 15 in this
case. The connection of the steam inlet 12 to the housing 15 is
preferably created in an equatorial plane 16 of the housing 15. In
the case of the preferred upright arrangement of the cyclone
separator 6 or of the housing 15, the equatorial plane 16 extends
essentially horizontally.
[0030] The steam outlet 13, in the case of the upright housing 15,
is preferably arranged at the top, in fact especially coaxially to
the longitudinal center axis 9 of the housing 15. The longitudinal
center axes of the globular housing 15 are characterized in that
they all extend through the middle point of the housing 15, which
is not described in more detail. In the case of the upright housing
15, the longitudinal center axis 9 which is associated with the
steam outlet 13 extends essentially vertically. In the preferred
embodiment which is shown here the longitudinal center axis 9 which
is associated with the steam outlet 13 is perpendicular to the
previously mentioned equatorial plane 16 which is associated with
the steam inlet 12.
[0031] The outlet opening 14, in the case of the upright
arrangement of the housing 15, is preferably located at the lower
end of the housing 15. In the preferred embodiment which is shown,
the outlet opening 14 is arranged on the housing 15 coaxially to a
longitudinal center axis 9' of the housing 15. In the present
embodiment, the longitudinal center axis 9' which is associated
with the outlet opening 14 is arranged coaxially to the
longitudinal center axis 9 which is associated with the steam
outlet 13, i.e., the two longitudinal center axes 9 and 9'
coincide. Therefore, in the present case the longitudinal center
axis 9', which is associated with the outlet opening 14, is also
perpendicular to the equatorial plane 16 and extends essentially
vertically.
LIST OF DESIGNATIONS
[0032] 1 Steam turbine installation [0033] 2 Steam path [0034] 3
Steam turbine [0035] 4 Steam generator [0036] 5 Generator [0037] 6
Inertial separator/cyclone separator [0038] 7 Separated particles
[0039] 8 Steam flow [0040] 9, 9' Longitudinal center axis of 6
[0041] 10 Cylinder section of 6 [0042] 11 Cone section of 6 [0043]
12 Steam inlet [0044] 13 Steam outlet [0045] 14 Outlet opening of
11 or 15 [0046] 15 Housing [0047] 16 Equatorial plane
[0048] While the invention has been described in detail with
reference to exemplary embodiments thereof, it will be apparent to
one skilled in the art that various changes can be made, and
equivalents employed, without departing from the scope of the
invention. The foregoing description of the preferred embodiments
of the invention has been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit
the invention to the precise form disclosed, and modifications and
variations are possible in light of the above teachings or may be
acquired from practice of the invention. The embodiments were
chosen and described in order to explain the principles of the
invention and its practical application to enable one skilled in
the art to utilize the invention in various embodiments as are
suited to the particular use contemplated. It is intended that the
scope of the invention be defined by the claims appended hereto,
and their equivalents. The entirety of each of the aforementioned
documents is incorporated by reference herein.
* * * * *