U.S. patent application number 09/828471 was filed with the patent office on 2002-10-10 for bypass air injection method and apparatus for gas turbines.
Invention is credited to Kolman, Kevin Michael, Storey, James Michael.
Application Number | 20020144507 09/828471 |
Document ID | / |
Family ID | 25251902 |
Filed Date | 2002-10-10 |
United States Patent
Application |
20020144507 |
Kind Code |
A1 |
Kolman, Kevin Michael ; et
al. |
October 10, 2002 |
BYPASS AIR INJECTION METHOD AND APPARATUS FOR GAS TURBINES
Abstract
A bypass air injection scheme for a combustor of a gas turbine.
Combustor includes a body with an inner liner and a casing
enclosing the body with a passageway defined therebetween. A
predetermined amount of the compressor discharge air passing
through the passageway is extracted through a manifold. A conduit
feeds the extracted air into an injection manifold having a
plurality of injection tubes for injecting the extracted air into
the combustor bypassing the reactor. The injection tubes and the
injection manifold are disposed in a substantially common axial
plane.
Inventors: |
Kolman, Kevin Michael;
(Clifton Park, NY) ; Storey, James Michael;
(Albany, NY) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
8th Floor
1100 North Glebe Road
Arlington
VA
22201-4714
US
|
Family ID: |
25251902 |
Appl. No.: |
09/828471 |
Filed: |
April 9, 2001 |
Current U.S.
Class: |
60/723 ;
60/752 |
Current CPC
Class: |
F23C 13/00 20130101;
F23R 3/40 20130101 |
Class at
Publication: |
60/723 ;
60/752 |
International
Class: |
F23R 003/40 |
Claims
What is claimed is:
1. A combustor for a gas turbine, comprising: a combustor body with
an inner liner; a casing enclosing said body and defining a
passageway therebetween for carrying compressor discharge air; a
combustion chamber within said body for combustion of fuel and air;
a first manifold for extracting a predetermined amount of
compressor discharge air from said passageway; a second manifold
for receiving the extracted air and supplying the extracted air
into said body at a location bypassing said combustion chamber; and
a plurality of injection tubes in communication with said second
manifold for injecting the extracted air into said body to quench
combustion, said injection tubes and said second manifold being
disposed in a substantially common axial plane.
2. The combustor of claim 1, further comprising: an array of
openings disposed in said casing to permit the compressor discharge
air to flow through said openings into said first manifold; and a
conduit for supplying the extracted air from said first manifold to
said second manifold.
3. The combustor of claim 2, wherein said second manifold includes
an access flange for each injection tube.
4. The combustor of claim 3, wherein the injection tubes are
equally spaced from one another about said second manifold.
5. The combustor of claim 4, wherein first and second ends of said
conduit terminate in said first and second manifolds,
respectively.
6. The combustor of claim 5, wherein said conduit includes a
control valve to regulate air flowing from said first manifold to
said second manifold.
7. The combustor of claim 6, wherein said first and second
manifolds are disposed about an outer surface of said casing.
8. A combustor for a gas turbine, comprising: a combustor body; a
casing enclosing said body and defining a passageway therebetween
for carrying compressor discharge air; a catalytic reactor disposed
in said body for controlling pollutants released during combustion;
a first manifold for extracting a predetermined amount of
compressor discharge air from said passageway; a second manifold
for receiving the extracted air and supplying the extracted air to
said body at a location bypassing said catalytic reactor; and a
plurality of injection tubes in communication with said second
manifold for injecting the extracted air into said body, said
injection tubes and said second manifold being disposed in a
substantially common axial plane.
9. The combustor of claim 8, wherein said casing includes an array
of openings adjacent to said first manifold to enable the
compressor discharge air to flow through said openings into said
first manifold; and a conduit for supplying the extracted air from
said first manifold to said second manifold.
10. The combustor of claim 9, wherein said second manifold includes
an access flange for each of said injection tubes.
11. The combustor of claim 10, wherein the injection tubes are
equally spaced from one another about said second manifold.
12. The combustor of claim 11, wherein first and second ends of
said conduit terminate in said first and second manifolds,
respectively.
13. The combustor of claim 12, wherein said first and second
manifolds are disposed about an outer surface of said casing.
14. A gas turbine comprising: a compressor section for pressurizing
air; a combustor for receiving the pressurized air; and a turbine
section for receiving hot gases of combustion from the combustor,
said combustor including a combustor body with an inner liner, a
casing enclosing said body and defining a passageway therebetween
for carrying compressor discharge air, a combustion chamber within
said body for combustion of fuel and air, a first manifold for
extracting a predetermined amount of compressor discharge air from
said passageway, a second manifold for receiving the extracted air
and supplying the extracted air into said body at a location
bypassing said combustion chamber, and a plurality of injection
tubes in communication with said second manifold for injecting the
extracted air to said body to quench combustion, said injection
tubes and said second manifold being disposed in a substantially
common axial plane.
15. A gas turbine according to claim 14, wherein said casing
further includes an array of openings adjacent to said first
manifold to enable the compressor discharge air to flow through
said openings into said first manifold, and a conduit for supplying
the extracted air from said first manifold to said second
manifold.
16. The gas turbine of claim 15, wherein said second manifold
includes an access flange for each injection tube.
17. The gas turbine of claim 16, wherein the injection tubes are
equally spaced from one another about said second manifold.
18. The gas turbine of claim 17, wherein first and second ends of
said conduit terminate in said first and second manifolds,
respectively.
19. In a combustor comprising a body with an inner liner and a
casing enclosing said body defining a passageway therebetween, a
catalytic reactor disposed within said body, first and second
manifolds about said casing, and a conduit for connecting said
first and second manifolds, a method for quenching combustion
comprising the steps of: extracting a predetermined amount of
compressor discharge air, before the air flows into said reactor,
from said passageway into said first manifold; supplying said
extracted air from said first manifold to said second manifold via
said conduit; injecting the extracted air received by said second
manifold into said body at a location along the body bypassing said
reactor using an array of injection tubes; and disposing said
injection tubes and said second manifold in a substantially common
axial plane.
20. In a gas turbine comprising a compressor, a combustor, and a
turbine, said combustor including a body with an inner liner, a
casing enclosing said body defining a passageway therebetween for
carrying compressor discharge air, a catalytic reactor disposed
within said body, first and second manifolds disposed about said
casing, and a conduit for connecting said first and second
manifolds, a method for quenching combustion comprising the steps
of: extracting a predetermined amount of compressor discharge air,
before the air flows into said reactor, from said passageway into
said first manifold; supplying said extracted air from said first
manifold to said second manifold via said conduit; and injecting
the extracted air received by said second manifold into said body
at a location along the body bypassing said reactor using an array
of injection tubes; and disposing said injection tubes and said
second manifold in a substantially common axial plane.
Description
[0001] The present invention relates to gas turbines, and more
particularly, relates to a bypass air injection apparatus and
method to increase the effectiveness of the combustor by quenching
the combustion process.
BACKGROUND OF THE INVENTION
[0002] 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.
[0003] 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. Thus, there is a need to
compensate for the degradation of the catalytic reactor.
BRIEF SUMMARY OF THE INVENTION
[0004] Accordingly, the present invention is directed to a bypass
air injection apparatus and method to compensate for the
degradation of a catalytic reactor and to increase combustor
efficiency by extracting compressor discharge air prior to its
entry into a combustion or reaction zone of the combustor, and
re-injecting the extracted compressor discharge air into the
combustor bypassing the catalytic reactor using a plurality of
injection tubes located substantially in a common axial plane with
an injection manifold. Compressor discharge air is received by the
combustor in a first combustion chamber through a passageway,
preferably an annulus defined between a combustor body with an
inner liner and a casing enclosing the body. The first combustion
chamber includes a pre-burner stage where fuel is mixed with
compressor discharge air for combustion, thus raising the
temperature of the hot gases sufficiently to sustain a reaction
with the catalyst disposed downstream of the first combustion
chamber. Hot gases flowing out of the first combustion chamber pass
through a main fuel premixer (MFP) assembly for combustion in a
main combustion chamber disposed downstream of the catalyst.
[0005] A predetermined amount of compressor discharge air, flowing
through the annulus, and prior to reception in the first combustion
chamber, is extracted into a manifold. The extraction manifold is
disposed adjacent to an array of openings located in the casing
enabling compressor discharge air to flow from the annulus into the
extraction manifold. A bypass conduit connects the extraction
manifold to an injection manifold. The injection manifold lies in
communication with a plurality of injection tubes for injecting the
extracted air into the combustor body bypassing the catalyst. As
noted above, each injection tube and the injection manifold are
disposed in a substantially common axial plane. Removable flange
covers are provided on the injection manifold in substantial radial
alignment with the respective injector tubes affording access to
the tubes. The injection tubes are installed from the outside of
the injection manifold at circumferentially spaced locations about
the casing and the liner through flange covers. A bypass air(i.e.,
extracted air) path is therefore provided to bridge the backside
cooling airflow annulus disposed between the combustor casing and
the combustion liner.
[0006] In another embodiment, the combustor includes only one
combustion chamber. Thus, the combustor is devoid of the catalyst
and the MFP assembly. Here, main combustion occurs at the
pre-burner stage where a greater amount of fuel is mixed with air
in order for combustion to occur.
[0007] In one aspect, the present invention provides a combustor
for a gas turbine having a combustor body with an inner liner; a
casing enclosing the body and defining a passageway therebetween
for carrying compressor discharge air; a combustion chamber within
the body for combustion of fuel and air; a first manifold for
extracting a predetermined amount of compressor discharge air from
the passageway; a second manifold for receiving the extracted air
and supplying the extracted air into the body at a location
bypassing the combustion chamber; and a plurality of injection
tubes in communication with the second manifold for injecting the
extracted air into the body to quench combustion, the injection
tubes and the second manifold being disposed in a substantially
common axial plane. The combustor further includes an array of
openings disposed in the casing to permit the compressor discharge
air to flow through the openings into the first manifold; and a
conduit for supplying the extracted air from the first manifold to
the second manifold. The second manifold preferably includes an
access flange for each of the injection tubes. Preferably, the
injection tubes are equally spaced from one another about the
second manifold. The first and second ends of the conduit terminate
in the first and second manifolds, respectively. The conduit
includes a control valve to regulate air flowing from the first
manifold to the second manifold. The first and second manifolds are
preferably disposed about an outer surface of the casing.
[0008] In another aspect, the present invention provides a
combustor for a gas turbine including a combustor body with an
inner liner; a casing enclosing the body and defining a passageway
therebetween for carrying compressor discharge air; a catalytic
reactor disposed in the body for controlling pollutants released
during combustion; a first manifold for extracting a predetermined
amount of compressor discharge air from the passageway; a second
manifold for receiving the extracted air and supplying the
extracted air to the body at a location bypassing the catalytic
reactor; and a plurality of injection tubes in communication with
the second manifold for injecting the extracted air into the body,
the injection tubes and the second manifold being disposed in a
substantially common axial plane.
[0009] In another aspect, the present invention provides a gas
turbine having a compressor section for pressurizing air; a
combustor for receiving the pressurized air; and a turbine section
for receiving hot gases of combustion from the combustor, the
combustor including a combustor body with an inner liner, a casing
enclosing the body and defining a passageway therebetween for
carrying compressor discharge air, a combustion chamber within the
body for combustion of fuel and air, a first manifold for
extracting a predetermined amount of compressor discharge air from
the passageway, a second manifold for receiving the extracted air
and supplying the extracted air into the body at a location
bypassing the combustion chamber, and a plurality of injection
tubes in communication with the second manifold for injecting the
extracted air to the body to quench combustion, the injection tubes
and the second manifold are disposed in a substantially common
axial plane.
[0010] In yet another aspect, the present invention provides a
method for quenching combustion by extracting a predetermined
amount of compressor discharge air, before the air flows into the
reactor, from the passageway into the first manifold; supplying the
extracted air from the first manifold to the second manifold via
the conduit; injecting the extracted air received by the second
manifold into the body at a location along the body bypassing the
reactor using an array of injection tubes; and disposing the
injection tubes and the second manifold in a substantially common
axial plane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic cross-sectional illustration of a
combustor forming a part of a gas turbine and constructed in
accordance with the present invention;
[0012] FIG. 2 is a detailed illustration of the injection manifold
and the bypass injection scheme of the present invention;
[0013] FIG. 3 illustrates another embodiment of the invention
wherein a catalytic reactor is removed from the combustor; and
[0014] FIG. 4 shows a section of the combustor casing, of FIG. 1,
having an array of openings for extracting compressor discharge
air.
DETAILED DESCRIPTION OF THE INVENTION
[0015] As is well known, a gas turbine includes 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.
[0016] 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), a cylindrical body 16 with an inner liner 15,
and a casing 20 enclosing the body 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. Discharge air received from a compressor 40
via an inlet duct 38 flows through the annulus 18 and enters the
body 16 through a plurality of holes 22 provided on the body 16.
Compressor discharge air enters body 16 under a pressure
differential across the cap assembly 21 to mix with fuel from the
fuel injector assembly 12. The mixture is burnt by the pre-burner
assembly 11. Combustion occurs in a first combustion chamber or
first reaction zone 14 within the body 16 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 a 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 to mix with hot gases, exiting the first combustion
chamber 14, thus producing a combustion reaction in the main
combustion chamber 29, whereby the hot gases of combustion pass
through a transition piece 36 to drive the turbine (an inlet
section of which is shown at 42).
[0017] A predetermined amount of the compressor discharge air is
extracted from the annulus 18 into a manifold 26 via an array of
openings 25 (FIG. 4) 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. Air received in manifold 32 is injected by a plurality
of injection tubes 33 into body 16, bypassing catalyst 27. Each of
the injection tubes 33 and manifold 32 are located substantially in
a common axial plane. Further, each injection tube opens into body
16 through apertures 34 (FIG. 2). 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 are installed from the outside of the
injection manifold at circumferentially spaced locations about the
casing and the liner through flange covers. Members 35 and 39 (FIG.
2) cooperate to secure each injection tube 33 to body 16 in a
floating seal to provide a sealingly tight connection. Thus,
injected air cools the reaction and quenches the combustion
process.
[0018] Referring to FIG. 3, 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 amount of fuel
supplied to mix with compressor discharge air is greater than the
amount supplied in the presence of a catalyst. 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.
[0019] 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.
[0020] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *