U.S. patent application number 13/291441 was filed with the patent office on 2013-05-09 for combustor and method for supplying fuel to a combustor.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Patrick Benedict Melton, James Harold Westmoreland, III. Invention is credited to Patrick Benedict Melton, James Harold Westmoreland, III.
Application Number | 20130115561 13/291441 |
Document ID | / |
Family ID | 47143692 |
Filed Date | 2013-05-09 |
United States Patent
Application |
20130115561 |
Kind Code |
A1 |
Melton; Patrick Benedict ;
et al. |
May 9, 2013 |
COMBUSTOR AND METHOD FOR SUPPLYING FUEL TO A COMBUSTOR
Abstract
A combustor includes an end cover, an end cap downstream from
the end cover, and tubes that extend through the end cap. An outer
support tube extends downstream from the end cover and connects to
an upstream surface of the end cap. An inner support tube extends
downstream from the end cover and connects to a downstream surface
of the end cap. A first plenum surrounds the inner support tube
between the end cover and the upstream surface and extends radially
between the upstream and downstream surfaces. A second plenum
surrounds the first plenum between the end cover and the upstream
surface and extends radially between the upstream and downstream
surfaces.
Inventors: |
Melton; Patrick Benedict;
(Horse Shoe, NC) ; Westmoreland, III; James Harold;
(Greer, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Melton; Patrick Benedict
Westmoreland, III; James Harold |
Horse Shoe
Greer |
NC
SC |
US
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
47143692 |
Appl. No.: |
13/291441 |
Filed: |
November 8, 2011 |
Current U.S.
Class: |
431/8 ;
431/353 |
Current CPC
Class: |
F23R 3/286 20130101;
F23R 2900/00002 20130101 |
Class at
Publication: |
431/8 ;
431/353 |
International
Class: |
F23C 7/00 20060101
F23C007/00 |
Claims
1. A combustor, comprising: a. an end cover; b. an end cap
downstream from the end cover that extends radially across at least
a portion of the combustor, wherein the end cap comprises an
upstream surface axially separated from a downstream surface; c. a
plurality of tubes that extends from the upstream surface through
the downstream surface to provide fluid communication through the
end cap; d. an outer support tube that extends downstream from the
end cover and connects to the upstream surface of the end cap; e.
an inner support tube that extends downstream from the end cover
and connects to the downstream surface of the end cap; f. a first
plenum that surrounds the inner support tube between the end cover
and the upstream surface, wherein the first plenum extends radially
between the upstream and downstream surfaces; and g. a second
plenum that surrounds the first plenum between the end cover and
the upstream surface, wherein the second plenum extends radially
between the upstream and downstream surfaces.
2. The combustor as in claim 1, wherein the first plenum extends
radially inside the end cap downstream from the second plenum.
3. The combustor as in claim 1, wherein the first plenum is in
fluid communication with a first set of the plurality of tubes and
the second plenum is in fluid communication with a second set of
the plurality of tubes.
4. The combustor as in claim 1, further comprising a barrier that
extends between the first and second plenums, wherein the barrier
extends axially between the first and second plenums upstream from
the upstream surface.
5. The combustor as in claim 4, wherein the barrier extends
radially between the first and second plenums downstream from the
upstream surface.
6. The combustor as in claim 1, further comprising a fuel plenum
inside the inner support tube.
7. The combustor as in claim 1, further comprising a casing that
circumferentially surrounds at least a portion of the end cap to
define an annular passage between the end cap and the casing and a
support extends radially between the end cap and the casing in the
annular passage.
8. The combustor as in claim 1, further comprising a cap shield
that circumferentially surrounds the end cap.
9. The combustor as in claim 8, further comprising a sliding
engagement between the end cap and the cap shield.
10. A combustor, comprising: a. an end cover; b. a fuel conduit
that extends downstream from the end cover; c. a downstream surface
connected to the fuel conduit, wherein the downstream surface
extends radially across at least a portion of the combustor; d. an
upstream surface axially separated from the downstream surface,
wherein the upstream surface extends radially across at least a
portion of the combustor; e. a plurality of tubes that extends from
the upstream surface through the downstream surface to provide
fluid communication through the upstream and downstream surfaces;
f. a first plenum that surrounds the fuel conduit between the end
cover and the upstream surface, wherein the first plenum extends
radially between the upstream and downstream surfaces; and g. a
second plenum that surrounds the first plenum between the end cover
and the upstream surface, wherein the second plenum extends
radially between the upstream and downstream surfaces.
11. The combustor as in claim 10, wherein the first plenum extends
radially between the upstream and downstream surfaces downstream
from the second plenum.
12. The combustor as in claim 10, wherein the first plenum is in
fluid communication with a first set of the plurality of tubes and
the second plenum is in fluid communication with a second set of
the plurality of tubes.
13. The combustor as in claim 10, further comprising a barrier that
extends between the first and second plenums.
14. The combustor as in claim 10, further comprising an outer
support tube that extends downstream from the end cover and
connects to the upstream surface.
15. The combustor as in claim 10, further comprising a flexible
coupling between the end cover and the fuel conduit.
16. The combustor as in claim 10, further comprising a barrier that
extends between the first and second plenums, wherein the barrier
extends axially between the first and second plenums upstream from
the upstream surface.
17. The combustor as in claim 16, wherein the barrier extends
radially between the first and second plenums downstream from the
upstream surface.
18. A method for supplying fuel to a combustor, comprising: a.
flowing a working fluid through a plurality of tubes radially
arranged in an end cap, wherein the end cap extends radially across
at least a portion of the combustor; b. flowing at least one of a
first fuel or a first diluent through a first plenum, wherein the
first plenum is at least partially defined by an inner support tube
that connects to a downstream surface of the end cap; and c.
flowing at least one of a second fuel or a second diluent through a
second plenum that circumferentially surrounds at least a portion
of the first plenum, wherein the second plenum is at least
partially defined by an outer support tube that connects to an
upstream surface of the end cap.
19. The method as in claim 18, further comprising flowing a third
fuel inside the inner support tube.
20. The method as in claim 18, further comprising flowing at least
one of the first fuel or first diluent radially inside the end cap
downstream from the second plenum.
Description
FIELD OF THE INVENTION
[0001] The present invention generally involves a combustor and
method for supplying fuel to a combustor.
BACKGROUND OF THE INVENTION
[0002] Combustors are commonly used in industrial and power
generation operations to ignite fuel to produce combustion gases
having a high temperature and pressure. For example, gas turbines
typically include one or more combustors to generate power or
thrust. A typical gas turbine used to generate electrical power
includes an axial compressor at the front, one or more combustors
around the middle, and a turbine at the rear. Ambient air may be
supplied to the compressor, and rotating blades and stationary
vanes in the compressor progressively impart kinetic energy to the
working fluid (air) to produce a compressed working fluid at a
highly energized state. The compressed working fluid exits the
compressor and flows through one or more nozzles into a combustion
chamber in each combustor where the compressed working fluid mixes
with fuel and ignites to generate combustion gases having a high
temperature and pressure. The combustion gases expand in the
turbine to produce work. For example, expansion of the combustion
gases in the turbine may rotate a shaft connected to a generator to
produce electricity.
[0003] Various design and operating parameters influence the design
and operation of combustors. For example, higher combustion gas
temperatures generally improve the thermodynamic efficiency of the
combustor. However, higher combustion gas temperatures also promote
flashback or flame holding conditions in which the combustion flame
migrates towards the fuel being supplied by the nozzles, possibly
causing severe damage to the nozzles in a relatively short amount
of time. In addition, localized hot streaks in the combustion
chamber may increase the disassociation rate of diatomic nitrogen,
increasing the production of nitrogen oxides (NO.sub.X) at higher
combustion gas temperatures. Conversely, lower combustion gas
temperatures associated with reduced fuel flow and/or part load
operation (turndown) generally reduce the chemical reaction rates
of the combustion gases, increasing the production of carbon
monoxide and unburned hydrocarbons.
[0004] In a particular combustor design, a plurality of tubes may
be radially arranged in an end cap to provide fluid communication
for the working fluid to flow through the end cap and into the
combustion chamber. A fuel and/or a diluent may be supplied to the
end cap and injected into the tubes to enhance mixing between the
working fluid and fuel prior to combustion. The enhanced mixing
between the working fluid and fuel prior to combustion reduces hot
streaks in the combustion chamber that can be problematic with
higher combustion gas temperatures. As a result, the tubes are
effective at preventing flashback or flame holding and/or reducing
NO.sub.X production, particularly at higher operating levels.
However, an improved combustor and method for supplying fuel to the
combustor that allows for staged fueling, multiple fuels, and/or
diluents to be supplied to the tubes without obstructing the tubes
would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention are set forth below
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0006] One embodiment of the present invention is a combustor that
includes an end cover and an end cap downstream from the end cover
that extends radially across at least a portion of the combustor.
The end cap includes an upstream surface axially separated from a
downstream surface. A plurality of tubes extends from the upstream
surface through the downstream surface to provide fluid
communication through the end cap. An outer support tube extends
downstream from the end cover and connects to the upstream surface
of the end cap. An inner support tube extends downstream from the
end cover and connects to the downstream surface of the end cap. A
first plenum surrounds the inner support tube between the end cover
and the upstream surface, and the first plenum extends radially
between the upstream and downstream surfaces. A second plenum
surrounds the first plenum between the end cover and the upstream
surface, and the second plenum extends radially between the
upstream and downstream surfaces.
[0007] Another embodiment of the present invention is a combustor
that includes an end cover and a fuel conduit that extends
downstream from the end cover. A downstream surface connected to
the fuel conduit extends radially across at least a portion of the
combustor. An upstream surface axially separated from the
downstream surface extends radially across at least a portion of
the combustor. A plurality of tubes extends from the upstream
surface through the downstream surface to provide fluid
communication through the upstream and downstream surfaces. A first
plenum surrounds the fuel conduit between the end cover and the
upstream surface, and the first plenum extends radially between the
upstream and downstream surfaces. A second plenum that surrounds
the first plenum between the end cover and the upstream surface,
and the second plenum extends radially between the upstream and
downstream surfaces.
[0008] The present invention may also include a method for
supplying fuel to a combustor. The method includes flowing a
working fluid through a plurality of tubes radially arranged in an
end cap, wherein the end cap extends radially across at least a
portion of the combustor. The method further includes flowing at
least one of a first fuel or a first diluent through a first
plenum, wherein the first plenum is at least partially defined by
an inner support tube that connects to a downstream surface of the
end cap, and flowing at least one of a second fuel or a second
diluent through a second plenum that circumferentially surrounds at
least a portion of the first plenum, wherein the second plenum is
at least partially defined by an outer support tube that connects
to an upstream surface of the end cap.
[0009] Those of ordinary skill in the art will better appreciate
the features and aspects of such embodiments, and others, upon
review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0011] FIG. 1 is a simplified cross-section view of an exemplary
combustor according to one embodiment of the present invention;
and
[0012] FIG. 2 is a downstream cross-section view of the combustor
shown in FIG. 1 taken along line A-A.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Reference will now be made in detail to present embodiments
of the invention, one or more examples of which are illustrated in
the accompanying drawings. The detailed description uses numerical
and letter designations to refer to features in the drawings. Like
or similar designations in the drawings and description have been
used to refer to like or similar parts of the invention. As used
herein, the terms "first", "second", and "third" may be used
interchangeably to distinguish one component from another and are
not intended to signify location or importance of the individual
components. In addition, the terms "upstream" and "downstream"
refer to the relative location of components in a fluid pathway.
For example, component A is upstream from component B if a fluid
flows from component A to component B. Conversely, component B is
downstream from component A if component B receives a fluid flow
from component A.
[0014] Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that modifications and
variations can be made in the present invention without departing
from the scope or spirit thereof. For instance, features
illustrated or described as part of one embodiment may be used on
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0015] Various embodiments of the present invention provide a
combustor and method for supplying fuel to a combustor. The
combustor generally includes a plurality of tubes radially arranged
in an end cap to enhance mixing between a working fluid and fuel
prior to combustion. In particular embodiments, an inner and an
outer support may connect to the end cap, and multiple plenums may
supply one or more fuels and/or diluents to the end cap to flow
through the tubes. In other particular embodiments, a fuel conduit
may connect to the end cap to support the end cap, and plenums
surrounding the fuel plenum may supply one or more fuels and/or
diluents to the end cap to flow through the tubes. In this manner,
the various embodiments within the scope of the present invention
may reduce flow disturbances through the tubes, increase structural
support provided to the end cap, reduce manufacturing costs of the
combustor, and/or enable staged fueling and/or multiple fuels
and/or diluents to be supplied to the tubes over a wide range of
operating conditions without exceeding design margins associated
with flashback, flame holding, and/or emissions limits. Although
exemplary embodiments of the present invention will be described
generally in the context of a combustor incorporated into a gas
turbine for purposes of illustration, one of ordinary skill in the
art will readily appreciate that embodiments of the present
invention may be applied to any combustor and are not limited to a
gas turbine combustor unless specifically recited in the
claims.
[0016] FIG. 1 provides a simplified cross-section view of an
exemplary combustor 10 according to one embodiment of the present
invention, and FIG. 2 provides a downstream cross-section view of
the combustor shown in FIG. 1 taken along line A-A. As shown, a
casing 12 generally surrounds the combustor 10 to contain a working
fluid 14 flowing to the combustor 10, and an end cover 16 provides
an interface for supplying fuel, diluent, and/or other additives to
the combustor 10. Possible diluents may include, for example,
water, steam, working fluid, air, fuel additives, various inert
gases such as nitrogen, and/or various non-flammable gases such as
carbon dioxide or combustion exhaust gases supplied to the
combustor 10. An end cap 18 may extend radially across at least a
portion of the combustor 10, and the casing 12 may
circumferentially surround at least a portion of the end cap 18 to
define an annular passage 20 between the end cap 18 and the casing
12. The end cap 18 and a liner 22 may define at least a portion of
a combustion chamber 24 downstream from the end cap 18. In this
manner, the working fluid 14 may flow through the annular passage
20 along the outside of the liner 22 to provide convective cooling
to the liner 22. When the working fluid 14 reaches the end cover
16, the working fluid 14 may reverse direction to flow through the
end cap 18 and into the combustion chamber 24.
[0017] The end cap 18 may include an upstream surface 26 axially
separated from a downstream surface 28, and a shroud 29 may
surround the upstream and downstream surfaces 26, 28. A plurality
of tubes 30 may extend axially from the upstream surface 26 to the
downstream surface 28 to provide fluid communication through the
end cap 18. The particular shape, size, number, and arrangement of
the tubes 30 may vary according to particular embodiments. For
example, the tubes 30 are generally illustrated as having a
cylindrical shape; however, alternate embodiments within the scope
of the present invention may include tubes having virtually any
geometric cross-section. In addition, the tubes 30 may be radially
arranged across the end cap 18 in one or more sets or groups of
various shapes and sizes, with each set of tubes 30 having one or
more separate fuel supplies. For example, multiple tubes 30 may be
radially arranged around a fuel nozzle, or multiple sets of tubes
30 may be radially arranged across the end cap 18. One or more
fluid conduits may provide one or more fuels, diluents, and/or
other additives to each set of tubes 30, and the type, fuel
content, and reactivity of the fuel and/or diluent may vary for
each fluid conduit or set of tubes. In this manner, different
types, flow rates, and/or additives may be supplied to one or more
sets of tubes to enhance staged fueling of the tubes 30 over a wide
range of operating conditions.
[0018] The combustor 10 may include one or more structures that
extend downstream from the end cover 16 to support the end cap 18
and/or provide various fluid passages between the end cover 16 and
the end cap 18. For example, as shown in FIG. 1, the combustor 10
may include an inner support tube 40 and an outer support tube 42
that extend downstream from the end cover 16. The inner support
tube 40 may connect to the downstream surface 28 of the end cap 18
to partially support the end cap 18 axially inside the combustor
10. In particular embodiments, the inner support tube 40 may also
function as or include a fuel conduit 40 that extends downstream
from the end cover 16 to define a fuel plenum 44 inside the inner
support tube 40. In this manner, the inner support tube/fuel
conduit 40 may provide fluid communication from the end cover 16 to
the end cap 18 to supply fuel to the end cap 18 and/or combustion
chamber 24.
[0019] The outer support tube 42 may circumferentially surround the
inner support tube 40 and connect to the upstream surface 26 of the
end cap 18 to partially support the end cap 18 axially inside the
combustor 10. In addition, the outer support tube 42 may define one
or more fluid passages between the end cover 16 and the end cap 18.
For example, as shown in FIG. 1, a barrier 46 may extend axially
between the inner and outer support tubes 40, 42 upstream from the
upstream surface 26 to partially define first and second plenums
50, 52 between the inner and outer support tubes 40, 42. Downstream
from the upstream surface 26, the barrier 46 may extend radially
between the first and second plenums 50, 52 to further separate the
first and second plenums 50, 52 inside the end cap 18. As a result,
the first plenum 50 may circumferentially surround the inner
support tube/fuel conduit 40 between the end cover 16 and the
upstream surface 26 before extending radially inside the end cap 18
between the upstream and downstream surfaces 26, 28. Similarly, the
second plenum 52 may circumferentially surround the first plenum 50
between the end cover 16 and the upstream surface 26 before
extending radially inside the end cap 18 between the upstream and
downstream surfaces 26, 28. In the particular embodiment shown in
FIG. 1, the first plenum 50 thus extends radially inside the end
cap 18 downstream from the second plenum 52 with respect to the
direction of the working fluid 14 through the end cap 18.
[0020] The first and second plenums 50, 52 provide fluid
communication between the end cover 16 and the end cap 18 to allow
various fuels, diluents, or other fluid additives to be supplied to
the tubes 30. Each tube 30 in turn may include one or more ports 54
that provide fluid communication through the tube 30 from the first
and/or second fuel plenums 50, 52. The ports 54 may be angled
radially, axially, and/or azimuthally to project and/or impart
swirl to the fluid flowing through the ports 54 and into the tubes
30. In addition, the particular number, size, and location of the
ports 54 in the tubes 30 may be varied to allow staged fluid flow
to the tubes 30. For example, as shown in FIG. 1, a first set of
tubes 60 may include ports 54 that provide fluid communication with
only the first plenum 50, and a second set of tubes 62 may include
ports 54 that provide fluid communication with only the second
plenum 52. In this manner, the working fluid 14 may flow outside of
the end cap 18 through the annular passage 20 until it reaches the
end cover 16 and reverses direction to flow through the tubes 30.
In addition, a first fuel or diluent may flow around the tubes 30
in the first plenum 50 to provide convective cooling to the tubes
30 before flowing through the ports 54 and into the first set of
tubes 60 to mix with the working fluid 14. Similarly, a second fuel
or diluent may flow around the tubes 30 in the second plenum 52 to
provide convective cooling to the tubes 30 before flowing through
the ports 54 and into the second set of tubes 60 to mix with the
working fluid 14. The mixture from each set of tubes 60, 62 may
then flow into the combustion chamber 24.
[0021] The combustor 10 may also include additional structures for
supporting the end cap 18 and/or allowing thermal expansion between
the various components. For example, as shown in the particular
embodiment illustrated in FIGS. 1 and 2, the combustor 10 may
include a flexible coupling 64 between the end cover 16 and the
inner support tube/fuel conduit 40 and/or the barrier 46. The
flexible coupling 64 may include an expansion joint, bellows, or
other device that allows for axial displacement of the inner
support tube/fuel conduit 40 and/or barrier 46 caused by thermal
expansion and contraction of the outer support tube 42 and/or tubes
30. One of ordinary skill in the art will readily appreciate that
alternate locations and/or combinations of flexible couplings 64
are within the scope of various embodiments of the present
invention, and the specific location or number of flexible
couplings 64 is not a limitation of the present invention unless
specifically recited in the claims.
[0022] As further shown in FIGS. 1 and 2, the combustor 10 may also
include a support 66 that extends radially between the end cap 18
and the casing 12 in the annular passage 20. The support 66 may
have an airfoil shape to reduce flow resistance of the working
fluid 14 flowing across the support 66 in the annular passage 20.
In particular embodiments, the support 66 may be angled to impart
swirl to the working fluid 14 flowing through the annular passage
20. Alternately or in addition, the combustor 10 may include a cap
shield 68 that circumferentially surrounds the end cap 18 and/or a
sliding engagement 70 between the end cap 18 and the cap shield 68.
The cap shield 68 may be connected to the support 66 and/or the
shroud 29 that surrounds the end cap 18. The sliding engagement 70
may include a spring washer, a hula seal, or similar device and may
extend continuously around the end cap 18 or in segments around the
end cap 18, as shown in FIG. 2, to allow axial movement of the end
cap 18 with respect to the cap shield 68 and/or support 66. In
particular embodiments, the sliding engagement 70 may also provide
a variable radial stiffness to the end cap 18 to allow slight
modifications to the natural or resonant frequency of the end cap
18.
[0023] The various embodiments shown in FIGS. 1 and 2 provide
multiple combinations of methods for supplying fuel to the
combustor 10. For example, the working fluid 14 may be supplied
through the annular passage 20 and tubes 30 radially arranged in
the end cap 18. A first fuel or a first diluent may be supplied
through the first plenum 50 to the first set of tubes 60, and a
second fuel or a second diluent may be supplied through the second
plenum 52 to the second set of tubes 62. Alternately, or in
addition, a third fuel or third diluent may be supplied through the
fuel plenum 44 to the combustion chamber 24. The first, second, and
third fuels and diluents may be the same or different, thus
providing very flexible methods for providing staged fueling to
various locations across the combustor 10 to enable the combustor
10 to operate over a wide range of operating conditions without
exceeding design margins associated with flashback, flame holding,
and/or emissions limits.
[0024] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *