U.S. patent application number 10/711221 was filed with the patent office on 2006-03-02 for concentric fixed dilution and variable bypass air injection for a combustor.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to James Michael Storey.
Application Number | 20060042256 10/711221 |
Document ID | / |
Family ID | 35810427 |
Filed Date | 2006-03-02 |
United States Patent
Application |
20060042256 |
Kind Code |
A1 |
Storey; James Michael |
March 2, 2006 |
CONCENTRIC FIXED DILUTION AND VARIABLE BYPASS AIR INJECTION FOR A
COMBUSTOR
Abstract
A combustor for a gas turbine includes a combustor body having
an aperture and a casing enclosing the combustor body and defining
a passageway therebetween for carrying compressor discharge air.
There is at least one injection tube for supplying an amount of the
compressor discharge air into the combustor body and the injection
tube is disposed between the aperture and through the casing. A
collar is disposed at the passageway and surrounds the injection
tube so that the injection tube passes through the collar. A gap is
disposed between the collar and the injection tube. The collar has
a plurality of openings. A method for quenching combustion in a gas
turbine includes supplying a fixed amount of compressor discharge
air into a body of a combustor of the gas turbine and supplying a
variable amount of compressor discharge air into the body. The
fixed amount of compressor discharge air is disposed concentrically
around the variable amount of compressor discharge air.
Inventors: |
Storey; James Michael;
(Taylors, SC) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
1 River Road
Schenectady
NY
|
Family ID: |
35810427 |
Appl. No.: |
10/711221 |
Filed: |
September 2, 2004 |
Current U.S.
Class: |
60/772 ;
60/752 |
Current CPC
Class: |
F23R 3/06 20130101; F23R
3/26 20130101; F23R 2900/03341 20130101 |
Class at
Publication: |
060/772 ;
060/752 |
International
Class: |
F23R 3/04 20060101
F23R003/04 |
Claims
1. A combustor for a gas turbine comprising: a combustor body
having an aperture; a casing enclosing said body and defining a
passageway therebetween for carrying compressor discharge air; at
least one injection tube for supplying an amount of said compressor
discharge air into said combustor body, said injection tube is
disposed between said aperture and through said casing; and a
collar disposed at said passageway, wherein said collar surrounds
said injection tube so that said injection tube passes through said
collar and a gap is disposed between said collar and said injection
tube, said collar having a plurality of openings.
2. The combustor of claim 1, wherein said plurality of openings are
arranged and sized so that a predetermined amount of said
compressor discharge air is constantly supplied into said combustor
body.
3. The combustor of claim 1, wherein each of said plurality of
openings are about 0.6 centimeter to about 1.3 centimeter in
diameter.
4. The combustor of claim 1, wherein each of said plurality of
openings are arranged in equally spaced rows around said
collar.
5. The combustor of claim 1, wherein said collar having a first end
and a second end, said first end mounted to said combustor body and
said second end extending to said injection tube.
6. The combustor of claim 5, further comprising a retaining clip
that connects said collar to said body at said first end.
7. The combustor of claim 1, further comprising a space between an
outer diameter of said aperture of said body and an end of said
injection tube.
8. The combustor of claim 1, wherein said aperture is larger than
an outer span of said injection tube.
9. The combustor of claim 1, wherein said collar includes a
straight section that is mounted to said body and a sloped section
that extends to said injection tube.
10. The combustor of claim 9, wherein said straight section
includes said openings and said sloped section includes said
openings.
11. The combustor of claim 1, further comprising a catalytic
reactor disposed in said body for controlling pollutants released
during combustion.
12. The combustor of claim 1, further comprising a reaction zone
within said combustor body for main combustion of fuel and air.
13. The combustor of claim 1, wherein said amount of said
compressor discharge air from said at least one injection tube is
variable and said plurality of openings supplies a fixed amount of
said compressor discharge air into said compressor body.
14. A combustor for a gas turbine comprising: a combustor body
having an aperture; a casing enclosing said body and defining a
passageway therebetween for carrying compressor discharge air; at
least one injection tube for supplying a variable amount of said
compressor discharge air into said combustor body, said injection
tube is disposed between said aperture and through said casing; and
means for supplying a fixed amount of said compressor discharge air
into said body, said means for supplying said fixed amount of said
compressor discharge air disposed circumferentially around said at
least one injection tube for supplying a variable amount of said
compressor discharge air.
15. A combustor for a gas turbine comprising: a combustor body
having an aperture; a casing enclosing said body and defining a
passageway therebetween for carrying compressor discharge air; at
least one injection tube for supplying a variable amount of said
compressor discharge air into said combustor body, said injection
tube is disposed between said aperture and through said casing; and
a collar disposed at said passageway and mounted to said combustor
body and extending to said injection tube, said collar configured
to supply a fixed amount of said compressor discharge air to said
body.
16. A method for quenching combustion in a gas turbine comprising:
a combustor body having an aperture; a casing enclosing said body
and defining a passageway therebetween for carrying compressor
discharge air; at least one injection tube disposed between said
aperture and through said casing; and a collar disposed
concentrically around said at least one injection tube, the method
comprising: supplying a fixed amount of said compressor discharge
air into said combustor body through said collar; and supplying a
variable amount of said compressor discharge air into said
combustor body through said at least one injection tube, said fixed
amount of said compressor discharge air disposed concentrically
around said variable amount of said compressor discharge air.
Description
BACKGROUND OF THE INVENTION
[0001] Gas turbine manufacturers are currently involved in research
and engineering programs to produce new gas turbines that will
operate at high efficiency without producing undesirable air
polluting emissions. The primary air polluting emissions usually
produced by gas turbines burning conventional hydrocarbon fuels are
oxides of nitrogen, carbon monoxide and unburned hydrocarbons.
[0002] Catalytic reactors are generally used in gas turbines to
control the amount of pollutants as a catalytic reactor burns a
fuel and air mixture at lower temperatures, thus reduces pollutants
released during combustion. As a catalytic reactor ages, the
equivalence ratio (actual fuel/air ratio divided by the
stochiometric fuel/air ratio for combustion) of the reactants
traveling through the reactor needs to be increased in order to
maximize the effectiveness of the reactor with time.
BRIEF DESCRIPTION OF THE INVENTION
[0003] Exemplary embodiments of the invention include a combustor
for a gas turbine that includes a combustor body having an aperture
and a casing enclosing the combustor body and defining a passageway
therebetween for carrying compressor discharge air. There is at
least one injection tube for supplying an amount of the compressor
discharge air into the combustor body and the injection tube is
disposed between the aperture and through the casing. A collar is
disposed at the passageway and surrounds the injection tube so that
the injection tube passes through the collar. A gap is disposed
between the collar and the injection tube. The collar has a
plurality of openings.
[0004] Further exemplary embodiments of the invention include a
method for quenching combustion in a gas turbine that includes
supplying a fixed amount of compressor discharge air into a body of
a combustor of the gas turbine and supplying a variable amount of
compressor discharge air into the body. The fixed amount of
compressor discharge air is disposed concentrically around the
variable amount of compressor discharge air and is fed by the
plurality of said openings in the floating collars at each of the
injection locations into the body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a schematic cross-sectional illustration of a
combustor forming a part of a gas turbine.
[0006] FIG. 2 shows a section of the combustor casing of FIG. 1
having an array of openings for extracting compressor discharge
air.
[0007] FIG. 3 is a detailed illustration of a bypass injection
scheme.
[0008] FIG. 4 is a detailed illustration of a cross-section of a
floating collar as assembled in the bypass injection scheme.
[0009] FIG. 5 is a front view of the floating collar of FIG. 4.
[0010] FIG. 6 illustrates another embodiment of the invention in
which a catalytic reactor is removed from the combustor.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Gas turbines generally include a compressor section, a
combustion section and a turbine section. The compressor section is
driven by the turbine section typically through a common shaft
connection. The combustion section typically includes a circular
array of circumferentially spaced combustors. A fuel/air mixture is
burned in each combustor to produce the hot energetic gas, which
flows through a transition piece to the turbine section. For
purposes of the present description, only one combustor is
discussed and illustrated, it being appreciated that all of the
other combustors arranged about the turbine are substantially
identical to one another.
[0012] Referring now to FIG. 1, there is shown a combustor
generally indicated at 10 for a gas turbine including a fuel
injector assembly 12 having a single nozzle or a plurality of fuel
nozzles (not shown) and an inner liner assembly 13 that includes a
first reaction zone in combustion chamber 14, a cylindrical body
assembly 16, which is part of a main fuel premixer (MFP) assembly
24, and a main combustion chamber 29. The fuel injector assembly 12
also includes a casing 20 enclosing the body assembly 16 thereby
defining a passageway 18, preferably an annulus 18 therebetween. An
ignition device (not shown) is provided and preferably comprises an
electrically energized spark plug to ignite a fuel air mixture in
the preburner assembly 11 during turbine startup. Discharge air 44
received from a compressor 40 via an inlet duct 38 flows through
the annulus 18 and enters the preburner assembly 11 and body 16
through a plurality of holes 22 provided on the first combustion
chamber 14.
[0013] Compressor discharge air 44 enters body 16 under a pressure
differential across the cap assembly 21 to mix with fuel from the
fuel injector assembly 12. Combustion of this mixture occurs in a
first combustion chamber or first reaction zone 14 within the body
16 of the preburner assembly 11 thus raising the temperature of the
combustion gases to a sufficient level for the catalyst 27 to
react. Combustion air from the first combustion chamber 14 flows
through the main fuel premixer (MFP) assembly 24 and then through
catalyst 27 into the main combustion chamber or main reaction zone
29 for combustion. Additional fuel is pumped into the MFP assembly
24 to mix with hot gases, exiting the first combustion chamber 14,
thus producing a combustion reaction in the main combustion chamber
29. Accordingly, the hot gases of combustion pass through a
transition piece 36 to drive the turbine (an inlet section of the
turbine is shown at 42).
[0014] A predetermined amount of the compressor discharge air 44 is
extracted from the annulus 18 into a manifold 26 via an array of
openings 25 (FIG. 2) located in casing 20 and leading into an
opening 28 which sealingly mates with one end of a bypass conduit
30, while a second end of conduit 30 leads into an injection
manifold 32. A valve 31 regulates the amount of air supplied to
manifold 32 from manifold 26. Air 44 received in manifold 32 is
injected by a plurality of injection tubes 33 into body assembly
16, bypassing catalyst 27. It is noted that while the exemplary
embodiment shows a circular tube for the injection tubes 33,
injection tubes 33 may be any shape and does not have to be
circular so long as the tube is hollow so as to allow the air to
travel through the tube. Each of the injection tubes 33 and
manifold 32 are located substantially in a common axial plane
normal to the combustor centerline (spaced around the circumference
of body assembly 16 in the same plane).
[0015] Referring to FIG. 3, each injection tube 33 opens into body
16 through apertures 34. Removable flange covers 23 are provided on
the injection manifold in substantial radial alignment with the
respective injector tubes 33 affording access to the tubes. The
injection tubes 33 are installed from the outside of the injection
manifold 32 at circumferentially spaced locations about the casing
20 and the body 16 through flange covers 23. In an exemplary
embodiment, there are four injection tubes 33 spaced about 90
degrees apart about the casing 20. The injected air cools the
reaction and quenches the combustion process.
[0016] Referring to FIGS. 3 and 4, a cross-section of half of the
combustor is illustrated. This becomes apparent with reference to
the combustor centerline, shown at number 58. Each of the injection
tubes 33 interface with the body 16 through a floating collar 60
having openings 61 (e.g. holes, slots, etc.) (also referred to as
collar openings). Once the compressor discharge air 44 reaches the
floating collar 60, the air 44 is defined as a predetermined amount
of air 62 and a variable amount of air 64. Floating collar 60
allows the predetermined amount of air 62 from the passageway 18 to
be constantly injected into the hot gas path 63 with the combustor.
The floating collar 60 also allows the variable amount of air 64,
which travels through the bypass conduit 30 and is controlled by
the valve 31 (see FIG. 1), to be injected into the hot gas path 63
of the combustor. Thus, the floating collar 60 allows a variable
amount of air 64 and a fixed amount of air 62, which is located in
an annulus concentrically around the outside of the variable amount
of air 64, to be injected into the hot gas path 63.
[0017] The injection tube 33 is inserted through the casing 20 and
the passageway 18 to the body 16. The injection tube 33 is
connected, e.g., threaded, to the casing 20. In an exemplary
embodiment, there is a space 66 between the body 16 and an end 68
of the injection tube 33. The space 66 exists so that during
operation of the combustor when the injection tube 33 and body 16
heat up and expand, the injection tube 33 does not extend past the
body 16.
[0018] The floating collar 60 is mounted to the body 16 at a first
end 70 and rests against the injection tube at a second end 72. The
collar 60 is a cylindrical member that surrounds the injection tube
33 at the passageway 18. The floating collar 60 has a predetermined
number of openings. The number and size of openings can be varied
so as to determine the amount of air 62 (fixed dilution flow) that
will be constantly supplied to the combustor. In an exemplary
embodiment, the openings 61 are approximately 0.6 centimeters to
approximately 1.3 centimeters in diameter and are aligned so that
there are two rows of 15 to 20 openings equally spaced around the
entire collar 60 in an angled section 86 of collar 60 and one row
of 15 to 20 openings equally spaced around the entire collar in a
straight section 88 of collar 60. However, the hole size, number,
and location will vary depending on the amount of fixed dilution
that would be desirable or required.
[0019] In an exemplary embodiment, the floating collar 60 is
mounted to the body 16 through a retaining clip 80. There can also
be two retaining clips 80 located on either side of the floating
collar 60. The retaining clip 80 fits over an extension 82 of the
body 16 and into a slot 84 at the first end 70 of the floating
collar 60. The retaining clip 80 is welded into place at the
extension 82. The retaining clip 80 limits the movement of the
floating collar 60 by keeping the floating collar 60 from spinning
and from lifting off of the extension 82 of the body 16.
[0020] In addition, when the injection tube is inserted through
passageway 18 to body 16, the aperture 34 in body 16 is larger than
end 68 of injection tube, which produces a gap 78. The aperture 34
is larger than end 68 because of the thermal expansion that occurs
in body 16 when the combustor is operating. Thermal expansion will
also cause the injection tube 33 to be in different positions
within aperture 34 depending on the state of the combustor. Thus,
at cold conditions, the injection tube will be in a certain
position relative to the aperture 34 and at full operation, the
injection tube will be at a different position relative to the
aperture 34. At full operation, the centerline of the injection
tube 33 will be located at the centerline of the aperture 34. In
the cold condition, the centerline of the injection tube 33 will be
offset from the centerline of the aperture 34.
[0021] Moreover, the floating collar covers up the gap 78 so that
the air 44 does not leak into the combustor, except through the
controlled condition of the openings 61. In addition, because the
air 62 passes through the openings 61 in floating collar 60 into a
cavity 90, there is a plenum that is created that feeds the fixed
concentric dilution, which surrounds the variable bypass dilution.
The plenum provides a uniform, controlled flow of air to the gap 78
(or annulus) around the outside of the injection tube 33, which is
then injected into the combustor flow in the form an annular
jet.
[0022] The advantage of having the floating collar 60 configured as
such is that the collar 60 provides for a controlled amount of
fixed concentric dilution flow to be injected around the variable
bypass flow regardless of the position of the injection tube 33
relative to the aperture 34. By having the fixed concentric
dilution flow, the necessary range of movement for the valve 31 to
actuate is less than if the fixed concentric dilution was included
in the flow through the valve 31. Thus, the properly sized valve 31
can be operated within its highest accuracy range, which allows for
fine tuning (better control) of the variable bypass flow. Also, by
having the fixed amount of dilution flow facilitated by the
floating collar 60, the necessary size of the manifolds 26 &
32, the bypass conduit 30, and the valve 31 are reduced since they
need to accommodate only the variable flow. The fixed concentric
dilution flow allows for increased consistency in jet mixing with
the main combustor flow 63 over the variable bypass flow range.
[0023] Referring to FIG. 6, a second embodiment is illustrated
wherein like elements as in the combustor of FIG. 1 are indicated
by like reference numerals preceded by the prefix "1". Here, the
combustor 110 comprises a combustion chamber or reaction zone 114
where main combustion occurs. Catalyst 27 and MFP assembly 24 are
absent in this embodiment. Here, compressor discharge air from
annulus 118 flows into manifold 126, and from manifold 126 via
conduit 130 flows into body 116 through injection tubes 133
bypassing the combustion chamber 114. Further, the total amount of
fuel supplied to mix with compressor discharge air is injected
through the fuel injector assembly 112 in the absence of the
catalyst and MFP assembly. It will be appreciated that the location
of the combustion chamber 114 need not necessarily lie in close
proximity to the fuel injector assembly 112. Rather it may be
located within body 116 between end member 143 and manifold 132.
Likewise, manifold 132 may be appropriately located along casing
120 to inject air into body 116 provided the combustion chamber is
bypassed in order to quench the combustion process. The same
floating collar 60 (see FIGS. 2-5) can be incorporated at injection
tubes 133 of combustor 110.
[0024] Thus, the present invention has the advantages of maximizing
the effectiveness of the catalytic reaction, thereby increasing the
efficiency of the combustor. The present invention further provides
a simple means of controlling the combustion process in a
non-catalytic combustor by providing for air control capability to
the combustion zone independent of machine (turbine) operation.
[0025] In addition, while the invention has been described with
reference to exemplary embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be made
to adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended claims.
Moreover, the use of the terms first, second, etc. do not denote
any order or importance, but rather the terms first, second, etc.
are used to distinguish one element from another.
* * * * *