U.S. patent application number 16/019089 was filed with the patent office on 2019-01-03 for combustion chamber of a gas turbine, gas turbine and method for operating the same.
The applicant listed for this patent is MAN DIESEL & TURBO SE. Invention is credited to Bernhard COSIC, Frank REISS, Gabrielle TEA-KEMPF.
Application Number | 20190003712 16/019089 |
Document ID | / |
Family ID | 62715805 |
Filed Date | 2019-01-03 |
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United States Patent
Application |
20190003712 |
Kind Code |
A1 |
COSIC; Bernhard ; et
al. |
January 3, 2019 |
COMBUSTION CHAMBER OF A GAS TURBINE, GAS TURBINE AND METHOD FOR
OPERATING THE SAME
Abstract
A combustion chamber assembly of a gas turbine, for combusting a
fuel in the presence of combustion air, includes: a combustion
chamber, in which combustion of fuel occurs; a precombustion
chamber upstream of the combustion chamber; an atomization device
that feeds a liquid fuel to the precombustion chamber; and a swirl
body that feeds combustion air and gaseous fuel to the
precombustion chamber. The combustion chamber assembly is
configured as a dual-fuel combustion chamber assembly, which, in a
gas fuel operating mode, feeds a mixture of a gaseous fuel and
combustion air to the combustion chamber via the swirl body, and
which, in a liquid fuel operating mode, feeds liquid fuel to the
combustion chamber via the atomization device and combustion air to
the combustion chamber via the swirl body. The atomization device
includes an atomization lance with a central atomization nozzle,
and plural decentralized atomization nozzles.
Inventors: |
COSIC; Bernhard;
(Duesseldorf, DE) ; REISS; Frank; (Lauchringen,
DE) ; TEA-KEMPF; Gabrielle; (Essen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MAN DIESEL & TURBO SE |
Augsburg |
|
DE |
|
|
Family ID: |
62715805 |
Appl. No.: |
16/019089 |
Filed: |
June 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 3/14 20130101; F23R
3/286 20130101; F23R 2900/00014 20130101; F23D 17/002 20130101;
F23R 3/343 20130101; F23R 2900/00015 20130101; F23R 3/36
20130101 |
International
Class: |
F23R 3/28 20060101
F23R003/28; F23R 3/14 20060101 F23R003/14; F23R 3/36 20060101
F23R003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 28, 2017 |
DE |
10 2017 114 362.9 |
Claims
1. A combustion chamber assembly of a gas turbine, for combusting a
fuel in the presence of combustion air, the combustion chamber
assembly comprising: a combustion chamber (1), in which combustion
of fuel occurs, the combustion chamber (1) being delimited by a
wall (2); a precombustion chamber (9), arranged upstream, in a fuel
feeding direction, of the combustion chamber (1); an atomization
device (4) configured to feed a liquid fuel to the precombustion
chamber (9); and a swirl body (3) configured to feed combustion air
and gaseous fuel to the precombustion chamber (9), wherein: the
combustion chamber assembly is configured as a dual-fuel combustion
chamber assembly, which, in a gas fuel operating mode, feeds a
mixture of a gaseous fuel and combustion air to the combustion
chamber (1) via the swirl body (3), and which, in a liquid fuel
operating mode, feeds liquid fuel to the combustion chamber (1) via
the atomization device (4) and combustion air to the combustion
chamber (1) via the swirl body (3), and the atomization device (4)
comprises: an atomization lance (17) with at least one atomization
nozzle (15, 16), the atomization lance (17) being centrally
arranged in the combustion chamber assembly with respect to a
longitudinal center axis (20) of the combustion chamber assembly
(1), and a plurality of atomization nozzles (18), the plurality of
atomization nozzles (18) being arranged in the combustion chamber
assembly in a decentralized manner with respect to the longitudinal
center axis (20) of the combustion chamber assembly.
2. The combustion chamber assembly according to claim 1, wherein
the decentralized atomization nozzles (18) are arranged on a
circular path (19) extending about the longitudinal center axis
(20).
3. The combustion chamber assembly according to claim 2, wherein a
center point of the circular path (19), on which the decentralized
atomization nozzles (18) are arranged, is positioned on the
longitudinal center axis (20).
4. The combustion chamber assembly according to claim 3, wherein
the circular path (19), on which the decentralized atomization
nozzles (18) are arranged, has a radius of between 0.4 times and
1.1 times an inner radius of the swirl body (3).
5. The combustion chamber assembly according to claim 1, wherein:
the centrally arranged atomization lance (17) comprises two
atomization nozzles (15, 16) which, alone and jointly, provide an
atomization cone (8a) with a maximum spray angle (.alpha.) of
60.degree. in each case, and each of the decentralized atomization
nozzles (18) provides an atomization cone (8b) with a maximum spray
angle (.beta.) of 50.degree..
6. The combustion chamber assembly according to claim 1, wherein
the centrally arranged atomization lance (17) is surrounded by an
adjoining component (5) at least in sections, so as to form
therebetween a radial gap (6) radially outside the centrally
arranged atomization lance (17), the combustion chamber (1) being
suppliable with combustion air via the radial gap (6) while
bypassing the swirl body (3).
7. The combustion chamber assembly according to claim 6, wherein
the combustion air flow fed via the radial gap (6) comprises
between 1% and 10% of the combustion air flow that is feedable to
the combustion chamber (1) via the swirl body (3).
8. The combustion chamber assembly according to claim 7, wherein
the radial gap (6) is configured to supply the combustion chamber
(1) with combustion air both in the gas fuel operating mode and in
the liquid fuel operating mode.
9. A gas turbine comprising: a combustion chamber assembly
according to claim 1; and a turbine for expanding exhaust gas
created during combustion in the combustion chamber assembly.
10. A method for operating a gas turbine according to claim 9,
comprising: supplying the combustion chamber (1) in the gas fuel
operating mode with a mixture of a gaseous fuel and combustion air
via the swirl body (3), and supplying the combustion chamber (1) in
the liquid fuel operating mode with a liquid fuel via the
atomization device (4) and combustion air at least via the swirl
body (3).
11. The method according to claim 10, wherein in the liquid fuel
operating mode both the centrally arranged atomization lance (17)
and the decentralized atomization nozzles (18) are utilized,
throughout an operating range between a no load state and a full
load state, to supply the combustion chamber (1) with the liquid
fuel.
12. The method according to claim 11, wherein via the centrally
arranged atomization lance (17), throughout the operating range
between the no load state and the full load state, a constant
quantity of liquid fuel is supplied to the combustion chamber (1),
and wherein power modulation is carried out by changing a quantity
of the liquid fuel fed to the combustion chamber (1) via the
decentralized atomization nozzles (18).
13. The method according to claim 10, wherein in the liquid fuel
operating mode, in an operating range below a predetermined load
limit, both the centrally arranged atomization lance (17) and the
decentralized atomization nozzles (18) are utilized to supply the
liquid fuel to the combustion chamber (1), whereas in an operating
range above the predetermined load limit the decentralized
atomization nozzles are utilized (18) exclusively for supplying the
liquid fuel to the combustion chamber (1).
14. The method according to claim 13, wherein in the operating
range below the predetermined load limit a constant quantity of
liquid fuel is supplied via the centrally arranged atomization
lance (17), wherein power modulation is carried out by changing a
quantity of the liquid fuel supplied to the combustion chamber (1)
via the decentralized atomization nozzles (18).
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates to a combustion chamber assembly,
having a combustion chamber, of a gas turbine, a gas turbine having
such a combustion chamber assembly and to a method for operating
such a gas turbine.
2. Description of the Related Art
[0002] Gas turbines comprise a combustion chamber and a turbine
arranged downstream of the combustion chamber. In the combustion
chamber of a gas turbine, a fuel is combusted and hot exhaust gas
created in the process. The hot exhaust gas is expanded in the
turbine of the gas turbine to extract energy in the process, which
can serve for providing drive power in order to, for example, drive
a generator for generating electric current. Gas turbines designed
as dual fuel turbines are already known from practice. Such dual
fuel gas turbines comprise a dual fuel combustion chamber in which
in a gas fuel operating mode a gaseous fuel and in a liquid fuel
operating mode a liquid fuel are combusted. In the gas fuel
operating mode, a mixture of a gaseous fuel and combustion air can
be fed to the combustion chamber via a swirl body. In the liquid
fuel operating mode, the liquid fuel can be fed to the combustion
chamber of the gas turbine via an atomization device and the
combustion air via the swirl body.
[0003] Thus, there is a need for further improving combustion
chambers of a gas turbine formed as dual fuel combustion chambers
so that, in particular in the liquid fuel operating mode, the
liquid fuel can be more effectively combusted, namely while
reducing undesirable exhaust gas emissions such as nitrogen oxide
emissions.
SUMMARY OF THE INVENTION
[0004] Starting out from the above, an object of the present
invention is to create a new type of combustion chamber assembly,
including a combustion chamber, of a gas turbine, a gas turbine of
such a combustion chamber assembly and a method for operating such
a gas turbine.
[0005] This object may be attained, in one aspect of the invention
through a combustion chamber assembly of a gas turbine in which,
the atomization device of which comprises, based on a longitudinal
center axis of the combustion chamber or based on a longitudinal
center axis of a precombustion chamber of the combustion chamber
assembly, a central atomization lance with at least one atomization
nozzle. The atomization device, furthermore, comprises multiple,
based on the longitudinal center axis of the combustion chamber or
based on the longitudinal center axis of the precombustion chamber
of the combustion chamber assembly, decentralized atomization
nozzles.
[0006] Via the central atomization lance, which comprises at least
one atomization nozzle, and via the multiple decentralized
atomization nozzles, the liquid fuel, in the liquid fuel operating
mode, can be optimally introduced into the combustion chamber to
ensure effective combustion of the liquid fuel. By way of the
central atomization lance, the liquid fuel can be directly
introduced into a central recirculation zone within the combustion
chamber or the precombustion chamber of the combustion chamber
assembly, as a result of which a stable combustion can be achieved.
Here, introducing the fuel via the central atomization lance does
not take place homogeneously to the combustion air, no premixing of
liquid fuel and combustion air takes place here. By way of the
decentralized atomization nozzles, the liquid fuel can be
homogeneously distributed in the combustion air. Furthermore, a
part premixing of liquid fuel and combustion air is achieved via
the decentralized atomization nozzle. By way of the decentralized
atomization nozzles, exhaust gas emissions, in particular nitrogen
oxide emissions, can be reduced compared with the central
atomization lance.
[0007] According to a further development of the invention, the
decentralized atomization nozzles are positioned on a circular path
extending about the longitudinal center axis of the combustion
chamber or about the longitudinal center axis of the precombustion
chamber of the combustion chamber assembly. Preferentially, a
center point of the circular path on which the decentralized
atomization nozzle is positioned, is positioned on the longitudinal
center axis of the combustion chamber or the precombustion chamber
of the combustion chamber assembly. Preferentially, a radius of the
circular path, on which the decentralized atomization nozzles are
positioned, preferably amounts to between 0.4 times and 1.1 times
and the inner radius of the swirl body. By way of such
decentralized atomization nozzles, with fuel, providing a
homogenous distribution of the same with the combustion air and
with respect to a premixing of the same with the combustion air can
be optimally introduced into the combustion chamber in order to
reduce exhaust gas emissions such as nitrogen oxide emissions as
much as possible.
[0008] According to a further development of the invention, the
central atomization lance comprises at least two, preferentially
two atomization nozzles, which alone and jointly each provide an
atomization cone with a maximum spray angle of 60.degree.,
preferentially of maximally 55.degree.. Each of the decentralized
atomization nozzles provides an atomization cone with a maximum
spray angle of 40.degree., preferentially of maximally 30.degree..
In this manner, it can be avoided that walls of the combustion
chamber and of the precombustion chamber are wetted with liquid
fuel. In particular, this serves for the effective combustion of
the liquid fuel while the reduction of exhaust gas emissions.
[0009] According to a further development of the invention, the
central atomization lance, while forming a radial gap, is bounded
by an adjoining component radially outside, at least in sections,
wherein the combustion chamber can be supplied with combustion air
via the radial gap while bypassing the swirl body. When using the
central atomization lance for introducing the liquid fuel into the
combustion chamber or precombustion chamber of the combustion
chamber assembly, an effective combustion of the liquid fuel in the
liquid fuel operating mode while reducing in particular nitrogen
oxide emissions can also be ensured by this.
[0010] According to a first version of the method according to an
aspect of the invention, both the central atomization lance and
also the decentralized atomization nozzles are utilized in the
liquid fuel operating mode throughout the operating range between
no load and full load in order to feed the liquid fuel to the
combustion chamber. This operating version of the invention is
suitable in particular when the gas turbine to be operated is to
perform rapid load changes since individual injection nozzles then
need not be activated or deactivated. Purging procedures, as are
required when switching off individual atomization nozzles, can be
avoided in this way. Compared with gas turbines, the combustion
chambers of which only have a central atomization lance, exhaust
gas emissions can be reduced.
[0011] According to a second version of the method according to an
aspect of the invention, both the central atomization lance and
also the decentralized atomization nozzles are utilized in the
liquid fuel operating mode in an operating range below a
predetermined load limit in order to feed liquid fuel to the
combustion chamber, whereas in an operating range above the
predetermined load limit exclusively the decentralized atomization
nozzles are utilized in order to feed the liquid fuel to the
combustion chamber. This operating version of the invention serves
for further reducing exhaust gas emissions, in particular nitrogen
oxide emissions. In an upper load range, the central atomization
lance for introducing the liquid fuel is not utilized further but
the introduction of the liquid fuel in the upper load range takes
place exclusively using the decentralized atomization nozzles.
Because of this, exhaust gas emissions such as nitrogen oxide
emissions can be further reduced namely in the operating range of
high loads.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Preferred further developments of the invention are obtained
from the description. Exemplary embodiments of the invention are
explained in more detail by way of the drawings without being
restricted to this. In the drawings:
[0013] FIG. 1 is a highly schematic extract from a combustion
chamber assembly of a gas turbine according to the invention;
[0014] FIG. 2 shows the area detail II of FIG. 1;
[0015] FIG. 3 is a detail of FIG. 1 in viewing direction III;
[0016] FIG. 4 is a diagram for illustrating a first method
according to the invention for operating the gas turbine according
to the invention; and
[0017] FIG. 5 is a diagram for illustrating a second method
according to the invention for operating the gas turbine according
to the invention.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0018] The invention relates to a combustion chamber assembly of a
gas turbine, to a gas turbine having such a combustion chamber
assembly and to a method for operating such a gas turbine.
[0019] FIG. 1 shows a schematic extract from a gas turbine in the
region of a combustion chamber 1. The combustion chamber 1 is
delimited by a wall 2, wherein in the combustion chamber 1 a fuel
is combusted. Exhaust gas generated during the combustion of the
fuel in the combustion chamber 1 can be fed to a turbine 100 of the
gas turbine in order to expand the exhaust gas in the turbine and
extract energy in the process.
[0020] The combustion chamber assembly is configured as dual fuel
combustion chamber assembly, which, on the one hand, can be
operated in a gas fuel operating mode and, on the other hand, can
be operated in a liquid fuel operating mode.
[0021] In the gas fuel operating mode of the combustion chamber
assembly, a gaseous fuel is combusted in the combustion chamber 1,
and a mixture of the gaseous fuel and combustion air is fed to the
combustion chamber 1, via a precombustion chamber 9 upstream of the
combustion chamber 1, via a swirl body 3.
[0022] The swirl body 3 is preferentially embodied as radial swirl
body and creates a defined swirl of the mixture of combustion air
and gaseous fuel entering the precombustion chamber 9 adjacent the
combustion chamber 1. The mixture of the gaseous fuel and the
combustion air is ignited in the gas fuel operating mode with the
help of an electric ignition device, which is not shown.
[0023] In the liquid fuel operating mode of the combustion chamber
assembly, a liquid fuel is combusted in the combustion chamber 1,
and the liquid fuel is fed to the combustion chamber 1, via the
precombustion chamber 9, with the help of an atomization device
4.
[0024] The atomization device 4 comprises a central atomization
lance 17 which is positioned approximately in the middle of the
precombustion chamber 9 or on a longitudinal center axis 20 of the
precombustion chamber 9 or on a longitudinal center axis 20 of the
combustion chamber 1 and injects the liquid fuel in the direction
of the longitudinal center axis 20 into the precombustion chamber 9
while forming an atomization cone or spray cone 8a.
[0025] In addition, with respect to the longitudinal center axis 20
of the combustion chamber 1, or of the precombustion chamber 9,
central atomization lance 17, the atomization device 4 comprises
multiple, based on the longitudinal center axis 20 of the
combustion chamber 1, or precombustion chamber 9, decentralized
atomization nozzles 18, which can likewise inject the liquid fuel
into the precombustion chamber 9, namely while forming a respective
spray cone 8b.
[0026] Accordingly, the atomization device 4 comprises the central
atomization lance 17 and multiple decentralized atomization nozzles
18. The central atomization lance 17 comprises at least one
atomization nozzle, preferentially multiple atomization nozzles 15,
16 (see FIG. 2).
[0027] FIG. 2 shows a detail of the central atomization lance 17 of
the atomization device 4. Between the atomization lance 17, which
is received in an assembly wall 12 of the combustion chamber
assembly, and an adjoining component 5, which is likewise received
in the assembly wall 12, which follows the atomization lance 17 of
the atomization device 4 radially outside and which surrounds the
atomization lance 17 of the atomization device 4 radially outside
at least in sections, a radial gap 6 is formed via which combustion
air can be likewise fed to the precombustion chamber 9, while
bypassing the swirl body 3. Accordingly, an arrow 13 (see FIG. 1)
visualises a flow of combustion air via the swirl body 3 and an
arrow 14 (see FIG. 2) a flow of combustion air via the radial gap 6
between the atomization lance 17 and the component 5, wherein the
combustion air flow via this radial gap 6 is conducted via a swirl
body 25.
[0028] The specific component 5, which together with the
atomization lance 17 of the atomization device 4 provides the
annular gap 6, is preferentially embodied as a separate sleeve
connected to the atomization lance 17. In contrast with this it is
also possible that the assembly wall 12 itself defines the
component 5 adjoining the atomization lance 17 radially outside,
which, together with the atomization lance 17, defines the radial
gap 6.
[0029] Based on the longitudinal center axis 20 of the combustion
chamber 1 or precombustion chamber 9, the decentralized atomization
nozzles 8 of the atomization device 4 are preferentially positioned
on a circular path 19 (see FIG. 3), which extends about the
longitudinal center axis 20 of the combustion chamber 1 or the
longitudinal center axis 20 of the precombustion chamber 9.
[0030] A center point of this circular path 19, on which the
decentralized atomization nozzles 18 are positioned, is positioned
on the longitudinal center axis 20 in this case. The decentralized
atomization nozzles 18 accordingly surround the central atomization
lance 17, preferentially concentrically.
[0031] FIG. 3 shows a radius d.sub.18 of the circular path 19, on
which the decentralized atomization nozzles 18 are arranged. Here
it is provided, in particular, that this radius dig of the circular
path 19, on which the decentralized atomization nozzles 18 are
positioned, amounts to between 0.4 times and 1.11 times an inner
diameter d.sub.3 of the swirl body 3. In particular, when the
radius d.sub.18 of the circular path 19, on which the decentralized
atomization nozzles 18 are arranged, amounts to between 1.0 times
and 1.1 times the inner diameter d.sub.3 of the swirl body 3 is the
swirl body 3 at least partly covered by the decentralized
atomization nozzles 18 in its outlet region.
[0032] The decentralized atomization nozzles 18 can also be
arranged on multiple preferentially concentric circular paths or on
an elliptical path or a polygon.
[0033] As already explained, the central atomization lance 17 of
the atomization device 4 preferentially comprises multiple
atomization nozzles, in the exemplary embodiment of FIG. 2, two
atomization nozzles 15, 16, which are preferentially swirl
atomization nozzles. These two atomization nozzles 15, 16 of the
central atomization lance 17 can be supplied with the liquid fuel
in the liquid fuel operating mode originating from a common liquid
fuel feed 21, wherein the fuel conducted from the liquid fuel feed
21 can be divided into two liquid fuel part feeds 21a, 21b in order
to supply both atomization nozzles 15, 16 of the central
atomization lance 17 with liquid fuel.
[0034] The central atomization lance 17 with both its atomization
nozzles 15, 16 sprays in the liquid fuel in the direction of the
combustion chamber 1 with the spray angle .alpha. which maximally
amounts to 60.degree., preferentially maximally 55.degree.. In
particular when both atomization nozzles 15, 16 of the atomization
lance 17 are jointly operated and also, in particular, when one of
these atomization nozzles 15, 16 is operated alone, does the spray
angle .alpha. amount to maximally 60.degree., preferentially
maximally 55.degree. in each case. Because of this it is ensured
that neither walls 2a of the precombustion chamber 9 nor walls 2 of
the combustion chamber 1 are wetted with liquid fuel, as a result
of which a more effective combustion of the liquid fuel can be
provided.
[0035] As already explained, combustion air can be fed via the gap
6 to the combustion chamber 1, via the precombustion chamber 9. The
air flow 14 conducted via this annular gap 6 serves, on the one
hand, for cooling the central atomization lance 17 of the
atomization device 4 while this air flow 14, on the other hand, at
least partly surrounds the spray cone 8a of the liquid fuel of the
atomization lance 17 on the outside, thus bundling the same.
[0036] The specific combustion air 14, which can be fed to the
combustion chamber 1, in FIG. 1, via the precombustion chamber 9,
while bypassing the swirl body 3 via the radial gap 6, amounts to
in particular between 1% and 10% of the combustion air that can be
fed to the combustion chamber via the swirl body 3.
[0037] Here, the combustion air flow 14 cannot only be fed to the
combustion chamber 1 via the radial gap 6 in the liquid fuel
operating mode but can also be fed via the radial gap 6 in the gas
fuel operating mode, In the gas fuel operating mode the atomization
device 4, i.e., in particular the atomization lance 17 of the same,
is inactive so that in the gas fuel operating mode no fuel is then
introduced via the atomization device 4, but is only supplied via
the swirl body 3.
[0038] As already explained, the atomization lance 17 is orientated
centrically, with respect to the longitudinal center axis 20;
liquid fuel can be introduced into a central recirculation zone via
the atomization lance 17 in the liquid fuel operating mode. Because
of this, a very stable combustion can be ensured. Introducing the
liquid fuel, based on the longitudinal center axis 20, via the
central atomization lance 17 accordingly takes place locally, i.e.,
not homogeneously to the combustion air, so that no premixing of
liquid fuel and combustion air takes place.
[0039] As already explained, the combustion chamber assembly, in
addition to the central atomization lance 17, comprises multiple
decentralized atomization nozzles 18, which are preferentially
arranged on the circular path 19. These decentralized atomization
nozzles 18 can be supplied with liquid fuel via a separate liquid
fuel feed 22 (see FIG. 1), wherein the decentralized atomization
nozzles 18 introduce the liquid fuel into the precombustion chamber
9 or combustion chamber 1 approximately in the same direction as
the central atomization lance 17, however with a spray angle .beta.
that is smaller than the spray angle .alpha., wherein the spray
angle .beta. of the decentralized atomization nozzles 18
preferentially amounts to maximally 40.degree., preferably
maximally 30.degree..
[0040] By virtue of the decentralized atomization nozzles 18, which
are preferentially equally distributed over the circular path 19,
the fuel, while forming a homogeneous distribution with the
combustion air, is introduced into the combustion chamber 1, via
the precombustion chamber 9, while at the same time a part
premixing of combustion air and liquid fuel is provided, in
particular supported in that the decentralized atomization nozzles
18 are arranged adjacent to the outlet of the swirl body 3. This
part premixing can be improved when the radius d.sub.18 is greater
than the radius d.sub.3. Accordingly, the radius d.sub.18 can
amount to between 1.0 times and 1.1 times the radius d.sub.3.
[0041] Preferentially double-jet nozzles or so-called plane jets
are utilized as decentralized atomization nozzles 18. By way of the
decentralized atomization nozzles 18 a homogeneous supply of the
liquid fuel to the combustion air is achieved and furthermore a
part premixing of liquid fuel and combustion air.
[0042] In particular when the combustion chamber assembly is to be
operated in the gas fuel operating mode is a gas-combustion air
mixture fed to the combustion chamber 1 via the swirl body 3.
[0043] In the gas fuel operating mode, combustion air can likewise
be conducted via the annular gap 6. The combustion air flow 14
conducted via the annular gap 6 is branched off in the region of an
air space, of a so-called plenum 10, upstream of the swirl body
3.
[0044] Accordingly, FIG. 1 shows an air line 11, via which the
combustion air can be branched off the plenum 10, wherein the
combustion air 14 branched off the plenum 10 is fed via the air
line 11 to an air chamber 7 formed by the wall 12 in order to then,
starting out from this air chamber 7, to be introduced into the
precombustion chamber 9 via the annular gap 6 formed between the
atomization lance 17 of the atomization device 4 and the adjoining
component 5.
[0045] In particular when the combustion chamber assembly is
operated in the liquid fuel operating mode with active atomization
device 4 is the liquid fuel fed to the combustion chamber 1 or
precombustion chamber 9 via the atomization device 4, combustion
air via the swirl body 3 and preferentially via the annular gap 6
between the central atomization lance 17 and the component 5.
[0046] In a first advantageous operating mode in the liquid fuel
operating mode both the central atomization lance 17 and also the
decentralized atomization nozzles 18 of the atomization device 4
are utilized throughout the operating range between no load and
full load in order to feed liquid fuel to the combustion chamber
1.
[0047] For this first operating condition, multiple curve profiles
21, 22, 23 and 24 are shown over the load L of the gas turbine, the
curve profile 21 corresponds to the liquid fuel feed 21 via the
central atomization lance 17, wherein the curve profile 22
corresponds to the liquid fuel feed 22 via the decentralized
atomization nozzles 18, the curve profile 23 shows the load
proportion in the total load L, which can be provided by the
combustion of the liquid fuel introduced via the central
atomization lance 17, and wherein the curve profile 24 shows the
load proportion in the total load L that can be provided by the
combustion of the fuel that is introduced into the combustion
chamber via the decentralized atomization nozzles 18.
[0048] Accordingly, FIG. 4 shows that, in particular when fuel is
fed to the combustion chamber 1 over the entire load range between
0% (no load) and 100% (full load) both via the central atomization
lance 17 and also via the decentralized atomization nozzles 18,
preferentially a constant quantity of liquid fuel is fed to the
combustion chamber 1 throughout the operating range between no load
(0%) and full load (100%) via the central atomization lance (17)
(see curve profile 21). Then, the power modulation is effected by
changing the liquid fuel introduced into the combustion chamber 1
via the decentralized atomization nozzles (18) (see curve profile
22) so that with increasing load demand L the load proportion 23 of
the central atomization lance 17 compared with the load proportion
of the decentralized atomization nozzles 18 decreases or the
corresponding load proportion 24 of the decentralized atomization
nozzles 18 increases.
[0049] According to this operating concept, in which throughout the
load range or operating range between no load and full load both
the central atomization lance 17 and also the decentralized
atomization nozzles 18 are utilized to feed the liquid fuel to the
combustion chamber it is provided, in particular, that during the
acceleration of the gas turbine of the combustion in the combustion
chamber 1 fuel is introduced into the combustion chamber 1
exclusively via one of the two atomization nozzles 15, 16 of the
atomization lance 17 and that following the acceleration and
following the reaching of a defined rotational speed of the gas
turbine both atomization nozzles 15, 16 of the atomization lance 17
are utilized and also to introduce the fuel into the combustion
chamber 1 via the atomization lance 17.
[0050] As already explained, the fuel quantity provided via the
central atomization lance 17 over the entire operating range and
thus load range of the gas turbine according to the operating
concept of FIG. 4 is constant, the power modulation is exclusively
effected by varying the fuel quantity provided via the
decentralized atomization nozzles 18. This operating concept is
suitable in particular for rapid load changes on the gas turbine
since, except for the ignition process, no atomization nozzles will
then have to be activated or deactivated. Nor is it required to
purge the atomization nozzles after the same have been deactivated.
This operating concept serves for a very robust and stable
combustion of the liquid fuel. In addition to this, low fuel
emissions can be realised, in particular nitrogen oxide emissions
of less than 150 vppm based on 15% of oxygen.
[0051] FIG. 5 illustrates a second operating concept of the
combustion chamber assembly according to the invention or of the
gas turbine according to the invention comprising the combustion
chamber assembly according to the invention. Accordingly, FIG. 5
shows that the load range L between no load (0%) and full load
(100%) is divided into two load ranges namely into a load range
between no load (0%) and a limit value (GW) and into a load range
between a limit value GW and full load (100%).
[0052] According to the second operating concept of FIG. 5
according to the invention, both the central atomization lance 17
and also the decentralized atomization nozzles 18 are utilized in
the liquid fuel operating mode in the operating range or load range
below the predetermined load limit GW in order to feed liquid fuel
to the combustion chamber 1. Here, the fuel quantity (see curve
profile 21) introduced via the central atomization lance 17 in this
load range is preferentially constant, the power modulation in turn
is again effected exclusively by changing the liquid fuel quantity
introduced via the decentralized atomization nozzles (18) (see
curve profile 22).
[0053] In the load range above the defined limit value GW, the
central atomization lance 17 is deactivated so that no fuel
whatsoever is supplied via the same so that in the upper load range
between the load limit GW and full load (100%) liquid fuel is then
exclusively fed to the combustion chamber 1 via the decentralized
atomization nozzles 18.
[0054] An advantage of this second operating concept according to
the invention consists in that at loads above the defined load
limit (GW) the liquid fuel is not centrally introduced into the
recirculation zone of the combustion chamber 1 but exclusively
decentralized, so that for the entire introduced liquid fuel a
homogeneous introduction to the combustion air and a part premixing
with combustion air can be ensured as a result of which exhaust gas
emissions, in particular nitrogen oxide emissions can be further
reduced compared with the operating concept of FIG. 4. In
particular, nitrogen oxide emissions of less than 90 vppm based on
15% oxygen can be realised
[0055] Thus, while there have been shown and described and pointed
out fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the device illustrated, and in its operation, may be made by those
skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
shown and/or described in connection with any disclosed form or
embodiment of the invention may be incorporated in any other
disclosed or described or suggested form or embodiment as a general
matter of design choice. It is the intention, therefore, to be
limited only as indicated by the scope of the claims appended
hereto.
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