U.S. patent application number 13/312116 was filed with the patent office on 2012-06-14 for combustion chamber and method for supplying fuel to a combustion chamber.
This patent application is currently assigned to ALSTOM TECHNOLOGY LTD. Invention is credited to Stefano BERNERO, Fernando BIAGIOLI, Fridolin HEYNEN, Douglas Anthony PENNELL.
Application Number | 20120148962 13/312116 |
Document ID | / |
Family ID | 44351681 |
Filed Date | 2012-06-14 |
United States Patent
Application |
20120148962 |
Kind Code |
A1 |
BERNERO; Stefano ; et
al. |
June 14, 2012 |
COMBUSTION CHAMBER AND METHOD FOR SUPPLYING FUEL TO A COMBUSTION
CHAMBER
Abstract
The combustion chamber has a body with nozzles to inject a fuel
to be burnt therein. The nozzles define a plurality of groups to be
fed in parallel. The nozzles of each group define at least two
stages that are differently operated according to the different
operating conditions. The combustion chamber also has a manifold
for collecting a fuel to be distributed among the groups, a
plurality of supply elements distributing the fuel originating from
the manifold to each group, for each group, splitters for diverting
the fuel coming from the supply elements between the stages.
Inventors: |
BERNERO; Stefano;
(Oberrohrdorf, CH) ; PENNELL; Douglas Anthony;
(Windisch, CH) ; BIAGIOLI; Fernando; (Fislisbach,
CH) ; HEYNEN; Fridolin; (Wurenlingen, CH) |
Assignee: |
ALSTOM TECHNOLOGY LTD
Baden
CH
|
Family ID: |
44351681 |
Appl. No.: |
13/312116 |
Filed: |
December 6, 2011 |
Current U.S.
Class: |
431/8 ;
431/354 |
Current CPC
Class: |
F23N 1/002 20130101;
F23R 3/28 20130101 |
Class at
Publication: |
431/8 ;
431/354 |
International
Class: |
F23C 5/00 20060101
F23C005/00; F23D 14/62 20060101 F23D014/62 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2010 |
EP |
10194320.7 |
Claims
1. Combustion chamber having a body with nozzles to inject a fuel
to be burnt therein, wherein: the nozzles define a plurality of
groups (13) to be fed in parallel, and the nozzles of each group
(13) define at least two stages (12a, 12b, 12c, 12d), that are
differently operated according to the different operating
conditions, the combustion chamber comprising: a manifold (14) for
collecting a fuel to be distributed among the groups (13), a
plurality of supply elements (15) distributing the fuel originating
from the manifold (14) to each group (13); and at least one
splitter (17) associated with each group for diverting the fuel
coming from the supply elements (15) between the stages (12a, 12b,
12c, 12d).
2. The combustion chamber according to claim 1, further comprising
a plurality of supply elements (15), each supply element (15) being
connected to another supply element (15).
3. The combustion chamber according to claim 1, wherein one main
line (19) to supply fuel into the manifold (14) is provided, the
main line (19) having a control valve (20) to regulate the fuel
flow within the manifold (14).
4. The combustion chamber according to claim 1, wherein each
splitter (17) can only divert the fuel flow among the stages (12a,
12b, 12c, 12d).
5. The combustion chamber according to claim 1, wherein, for each
group (13), each supply element (15) is defined by a duct, and
further ducts (22) are provided between the splitters (17) and the
nozzles of each stage (12a, 12b, 12c, 12d), the splitters (17)
comprise a control valve (25) on each duct operated by an actuator
(26).
6. The combustion chamber according to claim 5, wherein the
actuator (26) is a common actuator.
7. The combustion chamber according to claim 1, wherein for each
group (13), each supply element (15) is defined by a duct, and
further ducts (22) are provided between the splitters (17) and the
nozzles of each stage (12a, 12b, 12c, 12d), the splitters (17)
comprise a multiple-way control valve (28) to which the ducts are
connected.
8. The combustion chamber according to claim 1, wherein the
splitters (17) are locally controlled.
9. The combustion chamber according to claim 8, wherein the
splitters (17) are controlled on the basis of a fuel pressure
within the duct that carries them.
10. The combustion chamber according to claim 8, wherein the
splitters (17) are controlled on the basis of an open loop control
or closed loop control scheme.
11. The combustion chamber according to claim 1, wherein the
splitters (17) are centrally controlled.
12. The combustion chamber according to claim 11, wherein the
splitters (17) are controlled on the basis of an open loop control
or closed loop control scheme.
13. The combustion chamber according to claim 1, wherein the
combustion chamber is a premixed combustion chamber having mixing
devices (31) and at least one combustion device (30), wherein the
nozzles of each group (13) belong to same mixing device (31).
14. Method for supplying fuel to a combustion chamber having a body
with nozzles to inject a fuel to be burnt therein, wherein: the
nozzles define a plurality of groups (13) to be fed in parallel,
and the nozzles of each group (13) define at least two stages (12a,
12b, 12c, 12d), that are differently operated according to the
different operating conditions, the method comprising: collecting
in a manifold (14) the fuel to be distributed among the groups
(13), distributing the fuel originating from the manifold (14) to
each group (13) via supply elements (15); diverting, for each group
(13), the fuel coming from the supply elements (15) between the
stages (12a, 12b, 12c, 12d).
Description
RELATED APPLICATION
[0001] The present application hereby claims priority under 35
U.S.C. Section 119 to European Patent application number
10194320.7, filed Dec. 9, 2010, the entire contents of which are
hereby incorporated by reference.
FIELD OF INVENTION
[0002] The present invention relates to a combustion chamber and a
method for supplying fuel to a combustion chamber. In particular,
reference to a combustion chamber of a gas turbine is made.
BACKGROUND
[0003] Combustion chambers are known to comprise a body into which
fuel and an oxidiser (typically compressed air) are injected to be
combusted and generate hot gases that are expanded in a
turbine.
[0004] Typically, in order to comply with emissions (NO.sub.x, CO,
uncombusted hydro carbon), pulsations, power optimisation, etc, the
fuel is supplied into the combustion chamber via a plurality of
stages.
[0005] Each stage (typically comprising a plurality of nozzles)
allows a fuel to be injected within the combustion chamber in a
particular position according to the current load.
[0006] With reference to FIG. 1, a traditional premixed combustion
chamber 1 is shown.
[0007] The premixed combustion chamber 1 has mixing devices 2 into
which fuel is supplied and mixed with the compressed air to form a
mixture that in burnt into a combustion device 3.
[0008] Each mixing device 2 has a plurality of stages identified by
4a, 4b, 4c (any number of stages is anyhow possible, often they are
between two and four) each typically comprising a plurality of
nozzles.
[0009] In order to supply fuel to these stages, a supply circuit 5
is provided, having manifolds 7a, 7b, 7b for each stage and
connected to a main line 8a, 8b, 8c supplying fuel into it; in
addition control valves 9a, 9b, 9c are provided, to regulate the
fuel flow to the manifolds 7a, 7b, 7c.
[0010] During operation the fuel is supplied to the manifolds 7a,
7b, 7c that distribute it.
[0011] In particular the mass flow distribution among the stages
4a, 4b, 4c is controlled via the valves 9a, 9b, 9c.
[0012] Even if largely used, this structure implies structural and
operating constrains.
Structural Constrains
[0013] The supply circuit 5 with a manifold for each stage is
complex and expensive; in particular the most expensive components
are the manifolds 7a, 7b, 7c, which are made up of rings running
over the whole combustion chamber circumference, and the valves 9a,
9b, 9c.
Operational Constrains
[0014] Operation during transient periods is very complex, since
the three valves 9a, 9b, 9c must be regulated at the same time; in
some cases this regulation can cause instabilities and, in extreme
cases, it can also cause flame extinction.
[0015] In addition, when one (or more) of these valves 9a, 9b, 9c
is closed, the relative manifold 7a, 7b, 7c must be purged with
air. During the following operation the air contained within the
manifold becomes hot and when the valve must be opened to supply
fuel within the manifold again, it is necessary to purge the same
manifold with air before fuel is introduced within it (to avoid
risks of explosions). For this reason, when the valve is opened,
first air enters the combustion chamber and only afterwards the
required fuel is injected. It is clear that in some cases this air
injection could be very troubling; for example, in case of
operation close to the lean blow off, flame extinction could
occur.
[0016] In addition, when the valves 9a and/or 9b and/or 9c are
open, in case their regulation must be changed (for example to
counter pulsations or increase flame stability), time is required
for the fuel pressure to be adjusted over the whole manifolds 7a
and/or 7b and/or 7c and up to the injectors 4a, 4b, 4c; this time
interval increases the time required for the regulation.
SUMMARY
[0017] The present disclosure is directed to a combustion chamber
having a body with nozzles to inject a fuel to be burnt therein.
The nozzles define a plurality of groups to be fed in parallel, and
the nozzles of each group define at least two stages, that are
differently operated according to the different operating
conditions. The combustion chamber includes a manifold for
collecting a fuel to be distributed among the groups, a plurality
of supply elements distributing the fuel originating from the
manifold to each group; and at least one splitter associated with
each group for diverting the fuel coming from the supply elements
between the stages.
[0018] In another aspect, the disclosure is directed to a method
for supplying fuel to a combustion chamber having a body with
nozzles to inject a fuel to be burnt therein. The nozzles define a
plurality of groups to be fed in parallel, and the nozzles of each
group define at least two stages, that are differently operated
according to the different operating conditions. The method
includes collecting in a manifold the fuel to be distributed among
the groups and distributing the fuel originating from the manifold
to each group via supply elements. The method also includes
diverting, for each group, the fuel coming from the supply elements
between the stages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Further characteristics and advantages of the invention will
be more apparent from the description of a preferred but
non-exclusive embodiment of the combustion chamber and method,
illustrated by way of non-limiting example in the accompanying
drawings, in which:
[0020] FIG. 1 is a schematic view of a traditional combustion
chamber;
[0021] FIGS. 2 through 5 schematically show different embodiments
of the invention;
[0022] FIG. 6 schematically shows an embodiment of the invention
implemented in a premixed combustion chamber;
[0023] FIG. 7 schematically shows an embodiment of the invention
implemented in a diffusion combustion chamber; and
[0024] FIG. 8 schematically shows a further embodiment of the
invention implemented in a premixed combustion chamber.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Introduction to the Embodiments
[0025] An aspect of the invention therefore includes providing a
combustion chamber and a method by which the combustion chamber is
simpler and the operating constrains are reduced.
[0026] Another aspect of the invention is to provide a combustion
chamber wherein the fuel response to valve regulation is very
quick.
[0027] These aspects are attained by providing a combustion chamber
and a method in accordance with the accompanying claims.
DETAILED DESCRIPTION
[0028] With reference to the figures, these show a combustion
chamber 10 having a body with nozzles to inject a fuel to be burnt
therein.
[0029] The nozzles define a plurality of groups 13 to be fed in
parallel, and the nozzles of each group 13 define at least two
stages 12a, 12b (each stage 12a, 12b generally includes a plurality
of nozzles; additional stages in addition to the two stages 12a,
12b described can also be provided, i.e. any number of stages is
possible); the stages 12a, 12b are differently operated according
to the different operating conditions, for example load.
[0030] In addition, a manifold 14, typically in the form of a ring,
that collects the fuel to be distributed between the stages 12a,
12b of the groups 13 is provided; advantageously one single
manifold 14 is provided, alternatively also more than one manifold
can be provided, in this case at least one manifold 14 feeds
different stages of different groups.
[0031] Connected to the manifold 14, supply elements 15 that
distribute the fuel originating from the manifold 14 to each group
13 are provided.
[0032] In addition, for each group 13, one or more than one
splitter 17 (according to the distribution scheme) for diverting
the fuel coming from the supply elements 15 between the stages 12a,
12b is also provided.
[0033] One main line 19 to supply fuel into the manifold 14 is
provided, the main line 19 has a control valve 20 to regulate the
fuel flow within the manifold 14.
[0034] For each group 13, each supply element 15 is defined by a
duct, and further ducts 22 are provided between the splitters 17
and the nozzles of each stage 12a, 12b (FIGS. 2 and 3).
[0035] Splitters 17 can have different configurations, but in all
cases they divert the fuel flow between the stages 12a, 12b but
cannot control the total flow (i.e. the fuel flow is only regulated
via the valve 20).
[0036] In an embodiment (FIG. 3) the splitters 17 comprise a
control valve 25 on each duct 15, 22, operated by an actuator 26;
preferably the actuator 26 is a common actuator (i.e. a single
actuator operating all the valves 25 of the particular splitter
17).
[0037] In a different embodiment (FIG. 2) the splitters 17 comprise
a multiple-way control valve 28 to which the ducts 15, 22 are
connected.
[0038] The number of stages can also be greater than only two
(FIGS. 4 and 5).
[0039] In this case a plurality of supply elements 15 are provided
for each group 13, each supply element 15 being connected to
another supply element 15.
[0040] In particular FIGS. 4 and 5 show examples with different
configurations of the splitters 17 already shown in FIGS. 2 and 3;
it is clear that any configuration is possible, that the splitter
used can be the same in all cases or different and each of the
splitter 17 shown and described can be located upstream or
downstream of the other according to the particular needs.
[0041] The splitters 17 can be locally controlled, for example they
can be controlled on the basis of the fuel pressure within the duct
15 that carries them.
[0042] Alternatively the splitters 17 can be centrally controlled,
i.e. they can be all connected to a control unit that drives them
according to the different operating conditions such as, for
example, load.
[0043] In both cases the following control schemes are possible:
[0044] open loop control that adjusts the fuel distribution
according to fixed or variable boundary conditions (for example
burner position within the combustion chamber, operating condition
such as load, load gradient, ambient conditions, fuel quantity,
flame temperature, etc). [0045] closed loop control that adjusts
the fuel distribution according to a measured parameter (for
example emissions, pressure fluctuation, pressure drop, flame
temperature, material temperature, fuel composition, etc). [0046]
mixing devices-to-mixing device difference control, i.e. the
operating differences among mixing devices can be pre-defined as a
function of given operating parameters (from open loop controllers)
or measured parameters (from closed loop controllers) or can be
self-adjusting based on optimisation algorithms linked to a closed
loop control.
[0047] Naturally, also combinations of locally and centrally
controlled splitters 17 are possible.
[0048] The operation of the combustion chamber is apparent from
that described and illustrated and is substantially the
following.
[0049] In the following reference to the embodiment of FIG. 4 is
made, operation of different embodiments is similar and not
described in detail.
[0050] Fuel is supplied via line 19 and valve 20 into the manifold
14; the valve 20 regulates the fuel flow, i.e. the amount of fuel
that enters the manifold 14 and that is distributed among the
groups 13.
[0051] From the manifold 14 the fuel enters the supply elements 15
and reaches the first splitters 17.
[0052] Each first splitter 17 can: [0053] divert the whole fuel to
the duct 22 and, thus supply the whole fuel to the first stage 12a;
[0054] divert the whole fuel to the second supply element 15
downstream of the supply element 15 directly connected to the
manifold 14. Since the second supply element 15 is also provided
with a splitter 17, the fuel is then diverted to a duct 22 that
feeds the second stage 12b and/or to another duct 22 that feeds the
third stage 12c; [0055] divert a part of the fuel to the duct 22
and thus to the first stage 12a and a part of the fuel to the
second supply element 15 downstream of the supply element 15
directly connected to the manifold 14. Also in this case, the fuel
is then diverted between a duct 22 that feeds the second stage 12b
and/or another duct 22 that feeds the third stage 12c.
[0056] It is clear that by appropriately diverting the fuel at the
splitters 17, the required fluid distribution among the stages 12a,
12b, 12c for each particular load can be achieved. Advantageously,
the combustion chamber in embodiments of the invention is simple,
because the most troubling and expensive component are the manifold
and the valve 20; the splitters 17 and their control system are not
troubling and are generally cheap.
[0057] In addition operation is much simpler than with traditional
combustion chambers. In fact only one single valve 20 controls the
fuel flow within the combustion chamber, thus regulation of a
plurality of valves that control the amount of fuel flow to a
plurality of manifolds is avoided.
[0058] In addition, since the splitters 17 only control the fuel
distribution among the stages, the fuel amount to each group 13 is
in all cases regulated via the valve 20, i.e. defective controls
and risks of providing a fuel amount too large or too low is
avoided.
[0059] Moreover, during operation the valve 20 is always open
(because when it is closed no fuel reaches the nozzles and the
flame extinguishes), no manifold purging with air is thus
necessary; this further simplifies the structure and reduces
possible troubling operating conditions that could be caused by air
that enters the combustion chamber when fuel is required
instead.
[0060] Advantageously, since the fuel regulation is made downstream
of the manifold 14, the regulation is very quick.
[0061] During operation, it is not mandatory that the staging of
different groups of nozzles be the same; i.e. the staging can be
the same for all groups of it can be different.
[0062] In the following, an example of locally controlled splitters
is described.
[0063] In this case, each supply element 15 receives (almost) the
same amount of fuel; then the splitters 17, on the basis of local
conditions that may be different over the circumference of the
combustion chamber, regulate the staging, i.e. the amount of fuel
supplied to each stage of the group.
[0064] In the following an example of centrally controlled
splitters is described.
[0065] Also in this case each supply element 15 receives (almost)
the same amount of fuel; then the splitters 17, on the basis of a
signal provided by the control unit, regulate the staging, i.e. the
amount of fuel supplied to each stage of the group.
[0066] In the following three schematic examples of a premixed
combustion chamber (FIG. 6), a diffusion combustion chamber (FIG.
7), and a different premixed combustion chamber (FIG. 8) are
described.
[0067] The premixed combustion chamber (FIG. 6) has a combustion
device 30 (for example with an annular shape) with mixing devices
31 connected upstream of it.
[0068] The mixing devices 31 can be made up of two or more shells
defining a cone swirl space; the shells define slots for air
introduction within the cone swirl shape. A lance is housed within
the cone swirl space.
[0069] A first stage 12a is for example defined by nozzles provided
at the lance (for example at the tip of the lance, it could be a
pilot stage) and a second stage 12b is defined by the nozzles at
the shells.
[0070] As schematically shown, one single ring shaped manifold 14
is provided with one single supply line 19 and valve 20.
[0071] From the manifold 14 the supply elements 15 extend and are
connected to the splitters 17; from the splitters 17 the ducts 22
that feed the first and second stages 12a, 12b depart.
[0072] In this embodiment the nozzles of each group 13 belong to
the same mixing device 31.
[0073] FIG. 7 shows a diffusion combustion chamber with a
combustion device 30 that is for example annular in shape. Nozzles
are connected to the combustion device 30 defining the stages 12a,
12b, 12c; also in these cases (even if mixing devices are not
provided and the nozzles directly face the combustion device 30)
the stages 12a, 12b, 12c are grouped in groups 13.
[0074] As shown, the ring shaped manifold 14 is provided connected
to a line 19 provided with the valve 20. From the manifold 14 the
supply elements 15 depart, each connected to a first splitter 17
that supplies fuel to a duct 22 feeding the first stage 12a and a
further supply element 15 connected downstream of the first
splitter 17. This further supply element 15 is connected to a
further splitter 17 that fees two ducts 22 connected to the second
stage 12b and third stage 12c.
[0075] Naturally also different types of combustion chambers are
possible, for example a can combustor combustion chamber can
implement the structure and the method in embodiments of the
present invention.
[0076] FIG. 8 shows an example in which a group 13 includes the
stages of a plurality of mixing devices 31.
[0077] Each mixing device 31 has the same features already
described with reference to the first example and FIG. 6. In this
example, the combustion chamber has four stages 12a through
12d.
[0078] In particular two stages 12a and 12b are common to two of
the mixing devices 31 of each group 13, and one single mixing
device has a third and fourth stage 12c and 12d; therefore during
operation the two mixing devices operated in common can for example
generate a flame with a higher temperature and the other mixing
device a flame with a lower temperature. Naturally in different
embodiments the groups 13 can include any number of mixing devices
operated in common with flame having a higher temperature and any
number of mixing device operated with a flame at a lower
temperature and the number of stages of each burner can also be
any, for example only one. A possible embodiment is thus a
combustion chamber with the features shown in FIG. 8, wherein the
mixing devices 31 have only one stage (i.e. the mixing devices 31
could have only the stages 12a and 12c; in this case each mixing
device or group of mixing devices 31 defines a stage).
[0079] The present invention also refers to a method for supplying
fuel to a combustion chamber.
[0080] With reference to FIG. 2, the method comprises: [0081]
collecting the fuel to be distributed among the groups 13 in the
manifold 14, [0082] distributing the fuel originating from the
manifold 14 to each group 13 via a supply element 15; [0083] for
each group 13, diverting the fuel coming from the supply elements
15 between the stages 12a, 12b (and possible further stages).
[0084] It should be understood that the features described may be
independently provided from one another.
[0085] In practice, the materials used and the dimensions can be
chosen at will according to requirements and to the state of the
art.
REFERENCE NUMBERS
Prior Art
[0086] 1 combustion chamber [0087] 2 mixing devices [0088] 3
combustion device [0089] 4a, 4b, 4c nozzles [0090] 5 supply circuit
[0091] 7a, 7b, 7c manifolds [0092] 8a, 8b, 8c main lines [0093] 9a,
9b, 9c control valves
Embodiment of the Invention
[0093] [0094] 10 combustion chamber [0095] 12a, 12b, 12c, 12d
stages [0096] 13 groups [0097] 14 manifold [0098] 15 supply element
[0099] 17 splitters [0100] 19 main line [0101] 20 control valve
[0102] 22 ducts [0103] 25 control valve [0104] 26 actuator [0105]
28 multiple way control valve [0106] 30 combustion device [0107] 31
mixing device
* * * * *