U.S. patent application number 14/239140 was filed with the patent office on 2014-07-31 for bypass steam line.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. The applicant listed for this patent is Peter Berenbrink, Frank Deidewig, Holger Gedanitz, Dirk Huckriede, Mario Koebe, Bernd Prade, Horst Uwe Rauh, Stephan Schestag. Invention is credited to Peter Berenbrink, Frank Deidewig, Holger Gedanitz, Dirk Huckriede, Mario Koebe, Bernd Prade, Horst Uwe Rauh, Stephan Schestag.
Application Number | 20140209044 14/239140 |
Document ID | / |
Family ID | 46603980 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140209044 |
Kind Code |
A1 |
Berenbrink; Peter ; et
al. |
July 31, 2014 |
BYPASS STEAM LINE
Abstract
A mixing unit for mixing water with steam in a bypass station is
provided. The mixing unit has a plurality of Laval nozzles arranged
in the mixing unit, which Laval nozzles are displaced axially with
respect to one another in a water steam direction, with the result
that the noise emissions are reduced overall.
Inventors: |
Berenbrink; Peter; (Bochum,
DE) ; Deidewig; Frank; (Essen, DE) ; Gedanitz;
Holger; (Bochum, DE) ; Huckriede; Dirk;
(Korschenbroich, DE) ; Koebe; Mario; (Mulheim an
der Ruhr, DE) ; Prade; Bernd; (Mulheim, DE) ;
Rauh; Horst Uwe; (Essen, DE) ; Schestag; Stephan;
(Oberhausen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Berenbrink; Peter
Deidewig; Frank
Gedanitz; Holger
Huckriede; Dirk
Koebe; Mario
Prade; Bernd
Rauh; Horst Uwe
Schestag; Stephan |
Bochum
Essen
Bochum
Korschenbroich
Mulheim an der Ruhr
Mulheim
Essen
Oberhausen |
|
DE
DE
DE
DE
DE
DE
DE
DE |
|
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
Munich
DE
|
Family ID: |
46603980 |
Appl. No.: |
14/239140 |
Filed: |
August 2, 2012 |
PCT Filed: |
August 2, 2012 |
PCT NO: |
PCT/EP2012/065121 |
371 Date: |
February 16, 2014 |
Current U.S.
Class: |
122/487 ;
261/118 |
Current CPC
Class: |
F02C 7/1435 20130101;
B01F 5/0428 20130101; B01F 2015/061 20130101; F02C 3/30 20130101;
F22G 5/123 20130101; B01F 15/063 20130101; F02C 7/16 20130101; F05D
2260/601 20130101; F05D 2220/31 20130101; F05D 2260/20 20130101;
B01F 5/0421 20130101; B01F 3/04056 20130101; F22G 5/126 20130101;
F01D 25/12 20130101; F05D 2260/96 20130101 |
Class at
Publication: |
122/487 ;
261/118 |
International
Class: |
F22G 5/12 20060101
F22G005/12 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2011 |
EP |
11179513.4 |
Claims
1. A mixing unit for mixing a flow medium with a cooling medium,
comprising a pipe conduit section, to which a mixing section is
coupled fluidically, the mixing section comprising a plurality of
Laval nozzles, through which the flow medium can flow, injection
ducts formed in the Laval nozzles through which the cooling medium
flows in such a way that mixing of the flow medium with the cooling
medium takes place, wherein the Laval nozzles are adjacent to one
another and arranged to be offset in relation to one another in the
direction of flow of the flow medium, and wherein the Laval nozzles
are coupled to a displacement device, allowing for displacement of
the Laval nozzles during operation.
2. The mixing unit as claimed in claim 1, wherein the Laval nozzles
are designed identically to one another.
3. The mixing unit as claimed in claim 1, wherein the injection
ducts are formed obliquely to the Laval nozzle wall.
4. The mixing unit as claimed in claim 1, wherein the flow medium
comprises steam.
5. The mixing unit as claimed in claim 1, wherein the cooling
medium comprises water.
6. The mixing unit as claimed in claim 1, wherein displacement
takes place electrically.
7. The mixing unit as claimed in claim 1, wherein displacement
takes place hydraulically.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2012/065121 filed Aug. 2, 2012, and claims
the benefit thereof. The International Application claims the
benefit of European Application No. EP11179513 filed Aug 31, 2011.
All of the applications are incorporated by reference herein in
their entirety.
FIELD OF INVENTION
[0002] The invention relates to a mixing unit for mixing a flow
medium with a cooling medium, having a pipe conduit section, to
which a mixing section is coupled fluidically, the mixing section
having a plurality of Laval nozzles through which the flow medium
can flow, there being formed in the Laval nozzles injection ducts
through which the cooling medium flows in such a way that mixing of
the flow medium with the cooling medium takes place.
BACKGROUND OF INVENTION
[0003] In steam power plants, steam is generated in a steam
generator which converts the thermal energy of the steam into
rotational energy in a turbo set coupled fluidically to the steam
generator. The rotational energy is finally converted into
electrical energy. As long as the steam power plant operates
continuously and the load on the electrical generator is
comparatively constant, the thermal dynamic conditions are
comparatively constant over time.
[0004] There are situations, however, in which the steam power
plant has to be adapted to rapidly changing load situations. It may
be, for example, that an incident occurs and the generator suddenly
has to be separated from the network. It may also happen that the
steam power plant has to change over from full load to part load
unpredictably. Such load changes are a challenge to the technology
for regulating the overall steam power plant. One possibility for
following or counteracting rapidly changing load situations is to
route the steam generated by the steam generator, and flowing
directly to the high-pressure subturbine during continuous
operation or full-load operation, directly to the condenser via a
bypass station. In this bypass station, devices are provided, which
mix the highly heated steam with water, in order thereby to change
the thermodynamic conditions of the steam. This water is injected
into the steam. According to the prior art, this takes place in a
bypass station in which is arranged a Laval nozzle having injection
ducts through which water is sprayed into the steam.
[0005] It has been shown, however, that, because of this, the noise
emission is comparatively high. Moreover, it has been shown that
the temperature distribution is not sufficiently homogeneous, thus
leading to a non-optimal operating behavior under part load.
[0006] Bypass stations used nowadays are composed essentially of a
bypass valve and of the bypass steam infeed. The bypass steam
infeed comprises a diaphragm, a water injection device and a mixing
pipe. When the steam power plant is started up or after a trip,
steam occurring in the steam turbines is cooled via the bypass
station by the injection of water and is introduced directly into
the condenser.
SUMMARY OF INVENTION
[0007] An object herein is to allow better mixing of the water with
the steam during operation and at the same time to reduce noise
emission.
[0008] This object is achieved by a mixing unit for mixing a flow
medium with a cooling medium, comprising a pipe conduit section, to
which a mixing section is coupled fluidically, the mixing section
comprising a plurality of Laval nozzles, through which the flow
medium can flow, there being formed in the Laval nozzles injection
ducts through which the cooling medium flows in such a way that
mixing of the flow medium with the cooling medium takes place,
Laval nozzles adjacent to one another being arranged so as to be
offset in relation to one another in the direction of flow of the
flow medium.
[0009] An aspect of the invention thus pursues the path of using a
plurality of diaphragm orifices, contrary to the existing concept
in which the steam flows through only a single diaphragm orifice.
The disadvantage arising from the use of a single diaphragm orifice
is that mixing is not optimal, particularly at the margins of the
mixing section. Better mixing and reduced noise emission are
achieved, using a plurality of diaphragm orifices.
[0010] An aspect of the invention is that two Laval nozzles
adjacent to one another are arranged so as to be offset in relation
to one another in the direction of flow. To cool the steam, in
bypass mode water is injected into the bypass steam line. In order
to achieve good atomization of the water and therefore effective
cooling, the steam, before being admixed, is routed through a Laval
nozzle or through a perforated diaphragm, with the result that the
flow velocity rises sharply. The high relative velocity between the
steam and the water drops leads to good atomization, but has the
disadvantage that the water drops do not reach into the core of the
steam stream and therefore the inner part or the inner core of the
steam stream is not sufficiently cooled. The Laval nozzles are in
this case displaced axially in the direction of flow of the flow
medium. When a flow passes through a Laval nozzle, a sound wave is
generated. The sound wave arises behind a Laval nozzle. If Laval
nozzles are additionally displaced axially with respect to one
another by a length, so that sound wave peaks and sound wave
troughs of different Laval nozzles adjacent to one another cancel
each other out, the overall sound emission is markedly reduced.
[0011] A feature here, therefore, is that the individual Laval
nozzles which are arranged adjacently to one another are mutually
displaced axially.
[0012] The Laval nozzles are coupled to a displacement device,
displacement of the Laval nozzles being possible during operation.
It is thus proposed to provide active displacement which can take
place electrically or hydraulically or by other means, so that the
Laval nozzle planes can be displaced with respect to one another in
such a way that different frequency bands can be influenced during
operation. Noise emission can thus be actively reduced in different
operating states.
[0013] In a first advantageous development, the Laval nozzles are
designed identically to one another. This leads to better
computability of the sound wave troughs and sound wave peaks, and
it can thus be predetermined more effectively by computations from
the sound emission how far axial displacement has to take
place.
[0014] In a further advantageous development, the Laval nozzles are
coupled to a displacement device, displacement of the Laval nozzles
being possible during operation. It is thus proposed to provide
active displacement which can take place electrically or
hydraulically or by other means, so that the Laval nozzle planes
can be displaced with respect to one another in such a way that
different frequency bands can be influenced during operation. Noise
emission can thus be actively reduced in different operating
states.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention, then, is explained in more detail by means of
an exemplary embodiment. In the drawings:
[0016] FIG. 1 shows a cross-sectional view of a conventional mixing
unit;
[0017] FIG. 2 shows a cross-sectional view of a mixing unit
according to the invention;
[0018] FIG. 3 shows a cross-sectional view of part of the mixing
unit.
DETAILED DESCRIPTION OF INVENTION
[0019] FIG. 1 shows a mixing unit 1 according to the prior art.
Such a mixing unit 1 is characterized by a pipe conduit section 2
in which a flow medium 3 flows in the direction of a mixing section
4. In this mixing section 4, a Laval nozzle 5 is arranged, in which
the flow medium is accelerated. Arranged in the Laval nozzle 5 are
injection ducts 6 through which a cooling medium, such as water,
flows. The cooling medium is mixed with the flow medium 3 in a pipe
section 7 which is connected fluidically to the mixing unit 4.
[0020] FIG. 2 shows an illustration according to the invention of
the mixing unit 1. The difference from the mixing unit 1 according
to FIG. 1 is that, in the mixing section 4, a plurality of Laval
nozzles 5a, 5b, 5c are arranged, through which the flow medium 3
flows and in each of which is formed an injection duct 6, by means
of which water is mixed with the flow medium. Furthermore, the
difference between the mixing unit 1 of FIG. 1 and that of FIG. 2
is that the Laval nozzles 5a, 5b, 5c are displaced with respect to
one another in the flow medium direction 8, which may also be
designated as the axial direction. As a result of this
displacement, the sound wave troughs, which coincide with sound
wave peaks of the adjacent Laval nozzles, are cancelled. An overall
reduction in sound emission is thereby achieved. Finally, the pipe
section 7 is connected to a condenser, not illustrated in any more
detail.
[0021] The axial displacement of the Laval nozzles 5a, 5b, 5c with
respect to one another may take place by active displacement by
means of electrical or hydraulic forces. This may take place during
operation where different operating states arise. Different
frequency bands can thereby be influenced, thus reducing noise
emission, overall, even during operation.
[0022] The frequency band can be measured during operation and the
diaphragms can then be displaced with respect to one another such
that noise emission becomes minimal. The most favorable axial
positions can be determined beforehand for each load point during
the commissioning of the plant, and these can then simply be input
during operation, without the frequency spectrum having to be
measured actively.
[0023] FIG. 3 shows by way of example an illustration of the
displacement of the Laval nozzles 5a and 5b. The Laval nozzle 5a is
displaced with respect to the Laval nozzle 5b by the length L. With
a sound frequency of 1000 Hz, this would give a sound velocity of
approximately 500 m/s, thus resulting in the required length of 0.5
m. This length may be set statically in the first approximation or,
as described further above, may be obtained, even during operation,
by active displacement.
* * * * *