U.S. patent application number 13/524504 was filed with the patent office on 2012-12-20 for combustor housing for combustion of low-btu fuel gases and methods of making and using the same.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Joel Meador Hall, Sergey Adolfovich Oskin, Scott Robert Simmons.
Application Number | 20120322013 13/524504 |
Document ID | / |
Family ID | 42145802 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120322013 |
Kind Code |
A1 |
Hall; Joel Meador ; et
al. |
December 20, 2012 |
Combustor Housing for Combustion of Low-BTU Fuel Gases and Methods
of Making and Using the Same
Abstract
A combustor housing includes an inlet cover plate having a
central inlet configured to receive a supply of one of a high BTU
content fuel or air and at least one radially-spaced, peripheral
fuel inlet configured to receive a supply of a low BTU content fuel
and an outlet cover plate having at least one radially-spaced,
peripheral fuel outlet. The combustor housing also includes a
peripheral sidewall joining the inlet cover and the outlet cover
and enclosing a plenum, the at least one peripheral fuel inlet
opening through the inlet cover plate into the plenum and the at
least one fuel outlet opening from the plenum through the outlet
cover plate. The central inlet opens into at least one conduit
which extends away from the central inlet and opens into at least
one high BTU content fuel conduit or air supply conduit that is
axially aligned with the at least one fuel outlet.
Inventors: |
Hall; Joel Meador; (Mauldin,
SC) ; Oskin; Sergey Adolfovich; (Saint-Petersburg,
RU) ; Simmons; Scott Robert; (Simpsonville,
SC) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
42145802 |
Appl. No.: |
13/524504 |
Filed: |
June 15, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12328346 |
Dec 4, 2008 |
8220272 |
|
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13524504 |
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Current U.S.
Class: |
431/351 |
Current CPC
Class: |
F23R 2900/00002
20130101; F23R 3/283 20130101; F23R 3/36 20130101 |
Class at
Publication: |
431/351 |
International
Class: |
F23C 7/00 20060101
F23C007/00 |
Claims
1. A combustor housing, comprising: an inlet cover plate having a
central inlet configured to receive a supply of one of a high BTU
content fuel or air and at least one radially-spaced, peripheral
fuel inlet configured to receive a supply of low BTU content fuel;
an outlet cover plate having at least one radially-spaced,
peripheral fuel outlet; and a peripheral sidewall joining the inlet
cover plate and the outlet cover plate and enclosing a plenum, the
at least one radially-spaced, peripheral fuel inlet opening through
the inlet cover plate into the plenum and the at least one
radially-spaced, fuel outlet opening from the plenum through the
outlet cover plate, the central inlet opening into at least one
conduit which extends away form the central inlet and opens into at
least one high BTU content fuel conduit or air supply conduit that
is axially aligned with the at least one radially-spaced, fuel
outlet.
2. The combustor housing of claim 1, wherein the inlet cover plate
comprises a plurality of radially-spaced, peripheral fuel inlets,
the outlet cover plate comprises a plurality of radially-spaced,
peripheral fuel outlets, and the central inlet opens into a
plurality of radially-spaced conduits which extend away from the
central inlet and open into respective ones of a plurality of high
BTU content fuel conduits or air supply conduits that are axially
aligned with the corresponding outlets.
3. The combustor housing of claim 2, further comprising a plurality
of radially-spaced protruding lugs extending from the inlet cover
plate into the plenum and axially aligned with and proximate to the
plurality of radially-spaced, outlets, the plurality of high BTU
content fuel conduits or air supply conduits disposed in the
radially-spaced protruding lugs.
4. The combustor housing of claim 3, wherein the central inlet is
configured to receive a high BTU content fuel, and the plurality of
radially-spaced conduits open into a respective plurality of high
BTU content fuel conduits.
5. The combustor housing of claim 4, wherein the plurality of high
BTU content fuel conduits are each spaced from and extend axially
through respective outlets creating a 360.degree. spacing between
them.
6. The combustor housing of claim 5, wherein the plurality of high
BTU content fuel conduits are concentrically spaced within the
respective outlets.
7. The combustor housing of claim 5, further comprising a plurality
of nozzles disposed on a side of the outlet cover plate away from
the plenum and enclosing the respective outlets and fuel conduits,
the plurality of nozzles having a respective plurality of nozzle
bores and firing ends, the fuel conduits spaced from and extending
axially away from the outlet cover plate through the outlets and
within the plurality of nozzle bores to a respective plurality of
injection ends, each injection end having a 360.degree. spacing
from the respective firing end within the plurality of nozzle
bores.
8. The combustor housing of claim 3, wherein the central inlet is
configured to receive air, and the plurality of radially-spaced
conduits open into a respective plurality of air conduits, and
wherein a respective plurality of high BTU fuel conduits are also
disposed in the radially spaced protruding lugs extending through
the inlet cover plate and axially within the plurality of air
supply conduits.
9. The combustor housing of claim 8, wherein the plurality of high
BTU fuel conduits and the plurality of air supply conduits are each
spaced from and extend axially through respective outlets creating
a 360.degree. spacing between them.
10. The combustor housing of claim 9, wherein the plurality of high
BTU content fuel conduits and plurality of air supply conduits are
concentrically spaced within the respective outlets.
11. The combustor housing of claim 9, further comprising a
plurality of nozzles disposed on a side of the outlet cover plate
away from the plenum and enclosing the respective outlets, the
plurality of nozzles having a respective plurality of nozzle bores
and firing ends, the plurality of high BTU content fuel conduits
and plurality of air supply conduits are radially spaced from and
extending axially away from the outlet cover plate through the
outlets and within the plurality of nozzle bores to a respective
plurality of injection ends, each injection end having a
360.degree. spacing from the respective firing ends within the
plurality of nozzle bores.
12. The combustor housing of claim 1, wherein the inlet cover plate
is integral with the sidewall and the plenum and the outlet cover
plate is attached within an opening in the sidewall opposite the
inlet cover plate.
13. The combustor housing of claim 1, wherein the inlet cover plate
is integral with the sidewall and the plenum and the outlet cover
plate covers an opening in the sidewall and is attached to an inlet
end of the sidewall.
14. The combustor housing of claim 12, wherein the inlet cover
plate further comprises an indexing protrusion and outlet cover
plate further comprises an indexing hole, wherein the outlet cover
plate is indexed to the inlet cover plate by location of the
indexing protrusion within the indexing hole.
15. The combustor housing of claim 1, wherein the outlet cover
plate is integral with the sidewall and the plenum and the inlet
cover plate is attached within an opening in the sidewall opposite
the outlet cover plate.
16. The combustor housing of claim 1, wherein the outlet cover
plate is integral with the sidewall and the plenum and the inlet
cover plate covers an opening in the sidewall and is attached to an
outlet end of the sidewall.
17. The combustor housing of claim 15, wherein the inlet cover
plate further comprises an indexing protrusion and outlet cover
plate further comprises an indexing hole, wherein the inlet cover
plate is indexed to the outlet cover plate by location of the
indexing protrusion within the indexing hole.
Description
RELATED APPLICATION
[0001] The present patent application claims the benefit of
priority from and is a continuation application of U.S.
Non-provisional Patent Application Ser. No. 12/328,346, filed on
Dec. 4, 2008.
BACKGROUND OF THE INVENTION
[0002] The subject matter disclosed herein relates to combustors
for a high-temperature gas turbine engine, and more particularly,
to combustor housings for use with fuel gas having a low BTU
content.
[0003] Uncertainties in the cost and availability of
petroleum-based fuels and natural gas, coupled with the desire to
use all available fuel sources have resulted in commercial interest
in the use of very low heating value gas fuels to power gas
turbines. Various designs have been proposed for the use of low
heating value gases, such as those having heating contents as low
as 2500 BTU/lbm and have generally consisted of adaptations of
existing combustor designs.
[0004] One example is U.S. Pat. No. 4,498,288 that describes a
combustor design whereby a portion of a low-BTU gas fuel is
injected through a traditional style fuel nozzle into a primary
burning zone and the balance of the low-BTU gas fuel is injected
through a secondary pipe into a main burning zone. This combustor
design does not consider or accommodate the need for large flow
areas upstream of combustion.
[0005] Another example, EP0310327A3 describes a combustor that is
similar to that described in U.S. Pat. No. 4,498,288 above in that
the balance of the low-BTU gas fuel is injected through a secondary
passage. However, in this case, both the primary and secondary
injection passages discharge into a single combustion zone. This
combustor design also does not consider or accommodate the need for
large flow areas upstream of combustion.
[0006] Still another example, U.S. Pat. No. 6,201,029 contains
another approach to burning low-BTU content gas fuels that again
involves downstream injection of a portion of the low-BTU content
fuel gas. This combustor design also does not consider or
accommodate the need for large flow areas upstream of
combustion.
[0007] Still another example, US2007/0275337 describes a combustor
in which a helical air swirler is modified to include fuel
injection into the swirling air passages, and indicates that such
injection is well-suited to the combustion of low-BTU synthesis gas
and that such a burner can operate in pre-mixed or diffusion mode
and can handle low or high levels of fuel heating value with
different fuel injection circuits. The radial air passages are
large relative to the conventional fuel passages, such that area is
available for injection of low BTU gas. This combustor design also
does not consider or accommodate the need for large flow areas
upstream of combustion.
[0008] As the calorific value (BTU or energy content, or Lower
Heating Value (LHV)) of gas fuels is reduced, the required flow
rate increases. This leads to an increased pressure loss through
passageways originally designed for fuels with higher energy
content. This loss of pressure comes at a great price to the
turbine cycle efficiency if the fuel compressor is driven by the
gas turbine. This problem is exacerbated in fuel gases having a
very low calorific value, such as those having a calorific value
less than 2500 BTU/lbm. It is even further exacerbated as the
number of separate inlets used for the very low energy content gas
are increased to provide the amount of such gas necessary for
combustion. Gas velocities through fuel flow passages may also be
high, leading to increased heat transfer from the metal walls to
the fuel gas, or vice versa. This can cause local thermal gradients
within the combustor leading to increased cyclic thermal stresses
and the possibility for degradation or failure of the various
combustor components. The design, development, machining and other
manufacturing processes employed to create multiple fuel flow
passages into the combustor or combustion chamber adds complexity
and cost to systems using multiple passages.
[0009] Therefore, it is desirable to reduce pressure losses
associated with the use of very low content fuels so as to improve
the system efficiency. It is also desirable to reduce gas velocity
to reduce thermal gradients and associated thermal stresses,
particularly where the fuel gas exits the combustor through the
nozzle, since this is the high-temperature portion of the
combustor. It is also desirable to simplify the combustor design,
particularly as it relates to the incorporation of multiple fuel
lines into the combustor to lower the complexity and cost of the
combustor.
BRIEF DESCRIPTION OF THE INVENTION
[0010] According to one aspect of the invention, a combustor
housing includes an inlet cover plate having a central inlet
configured to receive a supply of one of a high BTU content fuel or
air and at least one radially-spaced, peripheral fuel inlet
configured to receive a supply of low BTU content fuel. It also
includes an outlet cover plate having at least one radially-spaced,
peripheral fuel outlet. The combustor housing also includes a
peripheral sidewall joining the inlet cover and the outlet cover
and enclosing a plenum, the at least one peripheral fuel inlet
opening through the inlet cover plate into the plenum and the at
least one fuel outlet opening from the plenum through the outlet
cover plate. The central inlet opens into at least one conduit
which extends away from the central inlet and opens into at least
one high BTU fuel conduit or air supply conduit that is axially
aligned with the at least one fuel outlet.
[0011] According to another aspect of the invention, a method of
making a combustor housing includes providing an inlet cover plate
having a central inlet configured to receive a supply of one of a
high BTU content fuel or air, at least one radially-spaced
peripheral fuel inlet configured to receive a supply of a low BTU
content fuel, the inlet cover plate and an integral peripheral
sidewall partially enclosing a plenum. The at least one peripheral
fuel inlet opening through the inlet cover plate into the plenum.
The central inlet opening into at least one conduit which extends
away from the central inlet and opens into at least one high BTU
content fuel conduit or air supply conduit. The method also
includes providing an outlet cover plate having at least one
radially-spaced, peripheral fuel outlet opening from the plenum
through the outlet cover plate. Further, the method includes
attaching the outlet cover plate to the peripheral sidewall to
enclose the plenum, wherein the at least high BTU content fuel
conduit or air supply conduit is axially aligned with the at least
one fuel outlet.
[0012] According to yet another aspect of the invention, a method
of making a combustor housing includes providing an outlet cover
plate having at least one radially-spaced, peripheral fuel outlet
and an integral peripheral sidewall partially enclosing a plenum.
It also includes providing an inlet cover plate having a central
inlet configured to receive a supply of one of a high BTU content
fuel or air and at least one radially-spaced, peripheral fuel inlet
configured to receive a supply of a low BTU content fuel, the at
least one peripheral fuel inlet opening into the plenum, the
central inlet opening into at least one conduit which extends away
from the central inlet and opens into at least one high BTU fuel
conduit or air supply conduit. The method also includes attaching
the inlet cover plate to the peripheral sidewall to enclose the
plenum, wherein the at least one high BTU fuel conduit or air
supply conduit is axially aligned with the at least one fuel
outlet, the fuel outlet opening from the plenum through the outlet
cover plate.
[0013] According to yet another aspect of the invention, a method
of using a combustor housing includes providing a combustor housing
comprising an inlet cover plate having a central inlet configured
to receive a supply of one of a high BTU content fuel or air and at
least one radially-spaced, peripheral fuel inlet configured to
receive a supply of a low BTU content fuel; an outlet cover plate
having at least one radially-spaced, peripheral fuel outlet; and a
peripheral sidewall joining the inlet cover plate and the outlet
cover plate and enclosing a plenum, the at least one peripheral
fuel inlet opening into the plenum and the at least one fuel outlet
opening from the plenum through the outlet cover plate, the central
inlet opening into at least one conduit which extends away from the
central inlet and opens into at least one high BTU fuel conduit or
air supply conduit that is axially aligned with the at least one
fuel outlet. The method also includes providing a supply of gaseous
fuel having BTU content of less than 2500 BTU/lbm to the at least
one radially-spaced, peripheral fuel inlet, wherein the gaseous
fuel enters the plenum and is distributed to the at least one
radially-spaced, peripheral fuel outlet.
[0014] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0016] FIG. 1 is an exploded perspective view of an exemplary
embodiment of a combustor housing as disclosed herein;
[0017] FIG. 2 is a perspective view of the assembled housing of
FIG. 1;
[0018] FIG. 3 is a cross-sectional view of the combustor housing of
FIG. 2 taken along section 3-3;
[0019] FIG. 4 is a cross-sectional view of a second exemplary
embodiment of a combustor housing as disclosed herein;
[0020] FIG. 5 is a cross-sectional view of a third exemplary
embodiment of a combustor housing as disclosed herein;
[0021] FIG. 6 is a cross-sectional view of a fourth exemplary
embodiment of a combustor housing as disclosed herein;
[0022] FIG. 7 is a perspective cross-sectional view of an exemplary
embodiment of a partial combustor assembly as disclosed herein;
[0023] FIG. 8 is a perspective cross-sectional view of an exemplary
embodiment of a combustor assembly as disclosed herein; and
[0024] FIG. 9 is a perspective cross-sectional view of a second
exemplary embodiment of a partial combustor assembly as disclosed
herein.
[0025] FIG. 10 is a perspective cross-sectional view of an
exemplary embodiment of an inlet and associated flanges and piping
as disclosed herein; and
[0026] FIG. 11 is a perspective cross-sectional view of a second
exemplary embodiment of an inlet and associated flanges and piping
as disclosed herein.
[0027] The detailed description explains embodiments of the
invention, together with advantages and features, by way of example
with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0028] A combustor designed to supply large quantities of very low
BTU content gas fuel to a gas-turbine combustion system with
reduced pressure loss, uniform distribution of the fuel gas, and
improved material durability is disclosed. The combustor includes a
combustor housing that houses a single fuel supply plenum adapted
to receive fuel through multiple inlets from multiple fuel supply
lines. The plenum is formed from a metal body that is configured to
be connected to one or more fuel nozzles downstream and to one or
more fuel supply pipes upstream. The exemplary embodiments
disclosed include a cylindrical metal housing into which a gas
manifold or plenum is formed within a peripheral sidewall and may
include in a base portion thereof either of one or more fuel
outlets or fuel inlets. This housing also includes a cover plate to
which includes one or more fuel inlets or fuel outlets,
respectively. The inlets is configured to receive one or more inlet
supply pipes for delivery of low BTU content gas fuels and is
particularly suited for use with very low BTU content fuels. The
inlet side of the housing may also be configured to receive air as
well as starting fuels of higher energy content. The very low BTU
content gas fuels are delivered into the plenum and distributed
thereby to one or more nozzles disposed over outlets on the outlet
side of the combustor for delivery to and combustion in the
combustion chamber. The air, starting fuels or both are passed
through the center of the housing and into the nozzle for ignition
of the very low BTU content fuel gas flowing through the
nozzle.
[0029] The plenum is designed to provide a large flow area to
create a low flow velocity of the very low BTU content fuel and to
reduce the pressure loss at the combustor. The connection between
the plenum and the downstream fuel nozzle(s) is designed so that a
(360.degree.) spacing, such as annular spacing, is provided from
the plenum into each nozzle. The upstream or inlet side of the
housing is designed such that an increased area is available for
attachment of the fuel supply pipes. This combustor serves as the
fuel inlet and combustion source for a gas turbine combustion
system, which may operate on fuels with a large range of heating
values, while reducing pressure loss and non-uniformity of the gas
flow, even at the very high gas flow rates required for use of a
very low BTU content gas fuels. The combustors disclosed herein are
suitable for use many gaseous fuels, including low BTU content
fuels having a low BTU content down to about 2500 BTU/lbm, but is
particularly suited for use with gaseous fuel having a very low BTU
content less than 2500 BTU/lbm, and more particularly for fuels
having a very low BTU content of about 800 to 1500 BTU/lbm, and
even more particularly about 1000 BTU/lbm. The portions of the
housing described herein may be sealably joined by various joining
means, such as various welding processes or fastening means, such
as a plurality of threaded bolts.
[0030] Referring to FIGS. 1-3, a first exemplary embodiment of a
combustor housing 10 is illustrated. The combustor housing 10 has
an inlet cover plate 12 on an inlet side 14, an outlet cover plate
16 on an outlet side 18 and a peripheral sidewall 20. In this
embodiment, inlet cover plate 12 and sidewall 20 are formed from an
integral metal plate. The combustor housing 10 may have any
suitable shape or size, and may be formed from any suitable high
temperature material. In the embodiment of FIGS. 1-3, combustor
housing 10 is in the shape of a cylinder having a diameter of
between about 1.0-3.0 ft., and more particularly about 1.5 ft., and
a thickness of about 4-5 inches. Combustor housing 10 may be made
using any suitable material adapted to perform at operating
temperatures of up to about 600.degree. C., including various
grades of steel, such as stainless steels, as well as various,
Ni-based, Fe-based, Co-based and other high temperature metal
alloys and materials. Forming of the integral inlet cover plate 12
and sidewall 20 may be performed using any suitable method,
including the use of machining, grinding and the like.
[0031] As shown in FIGS. 3 and 7-10, the inlet cover plate 12 has a
central inlet 22, preferably in the form of a cylindrical central
bore, but with other inlet shapes also being possible. Central
inlet 22 is configured to receive a supply of one of a relatively
higher BTU content starting fuel or air through a supply pipe 24.
Central inlet 22 may also have an attachment flange 26 disposed
thereon for attachment of supply pipe 24, but may also include
other suitable attachment means for attaching supply pipe 24 for
the high BTU content fuel or air. Supply pipe 24 and attachment
flange 26 may be attached by welds 28 as shown in FIG. 9, or by
other suitable attachment means.
[0032] Inlet cover plate 12 also includes at least one
radially-spaced, peripheral fuel inlet 30. Peripheral fuel inlet 30
may have any suitable shape or size. More particularly, fuel inlet
30 may have the form of a cylindrical inlet bore having a bore
diameter, by way of a non-limiting example, of about 3-5 inches. As
used herein, "radially-spaced" and "peripheral" should be broadly
understood to indicate that the item referred to, in this case the
at least one fuel inlet 30, is generally positioned away from the
center of the object on which it is located, in this case the inlet
cover plate 12, and that it is spaced radially with respect to
other openings that may extend through the object in a similar
manner. It is not limiting as to the distance from the center or
the radial spacing with respect to, in the case of inlets, other
inlets or openings, or, in the case of outlets, other outlets or
openings. While one fuel inlet 30 may be included, inlet cover
plate 12 is particularly well suited to include a plurality of fuel
inlets 30, as shown in FIGS. 1-3, 7 and 8. Fuel inlet 30 is
configured to receive a supply of low BTU content fuel through one
or more low BTU content fuel supply pipe 32, as shown in FIGS. 7
and 8. Low BTU content fuel supply pipe 32 and associated
attachment flange 34 may be attached by welds 36 as shown in FIG.
9, or by other suitable attachment means, including the use of
threaded bolts. The upstream or inlet side of the combustor housing
10 is designed such that has a large area available for attachment
of multiple fuel supply pipes, as shown in FIG. 9 and is
particularly desirable when using very low BTU content fuels, such
as blast furnace gases.
[0033] Combustor housing 10 further includes a peripheral sidewall
20 joining the inlet cover plate 12 and the outlet cover plate 16.
Peripheral sidewall 20 may have any suitable size and shape. In the
embodiments shown herein, peripheral sidewall 20 has a generally
cylindrical shape, with the range of diameters and thicknesses
described herein. The thickness of sidewall 20 will be selected to
accommodate the pressures associated with the flow of low BTU
content fuel gases into the combustor housing 10, as described
herein, but generally will be about 3 to 8 inches. In the
embodiment shown in FIGS. 3, 7-10, peripheral sidewall 20 is
integrally formed with inlet cover plate 12, and as noted above,
may be formed by any suitable manufacturing process, including
machining or grinding.
[0034] Peripheral sidewall 20 encloses a plenum 38 or cavity.
Plenum 38 may have any suitable size or shape. In the embodiments
shown herein, plenum 38 includes a generally cylindrical or bowl
shaped cavity. The peripheral fuel inlet 30 or inlets, open into
the inlet side 37 of the plenum 38 (see FIG. 7). At least one
radially-spaced, peripheral fuel outlet 40 opens outwardly away
from plenum 38 on the combustion side 41 of the plenum 38 toward
the combustion chamber (not shown), and a plurality of peripheral
fuel outlets 40 may be used, depending on the design requirements,
particularly the energy output required from the combustor. The
plenum 38 is designed to provide an enlarged flow area upstream of
the combustion chamber to create a low flow velocity of the large
quantities of very low BTU content fuel and to reduce the pressure
loss at the combustor. In the embodiment of FIGS. 1-3, the plenum
38 is generally cylindrical with a diameter of about 25 inches, and
a depth or thickness in the radially outward portion of the plenum
where it is most open of about 3 inches. Opposite the inlet cover
plate 12, plenum 38 and peripheral sidewall 20 define an opening 39
that is configured to receive outlet cover plate 16. Opening 39 has
a generally cylindrical shape and a diameter in the range of 15 to
20 inches, and more particularly 18 inches.
[0035] As shown in FIGS. 1-3, inlet cover plate 12 also includes a
plurality of protruding lugs 42 that protrude into plenum 38 toward
the outlet cover plate 16. The protruding lugs 42 may be located on
a raised portion 44 of inlet cover plate 12, as shown in FIGS. 1-3.
Raised portion 44 provides enhanced strength and stiffness to the
center of inlet cover plate 12 where radially-spaced, peripheral
protruding lugs 42 are located. In the embodiment of FIGS. 1-3,
raised portion 44 has a diameter of about 2 to 5 inches and
projects into the plenum 38 about 2 inches. Protruding lugs 42 may
have any suitable width, height and shape and any number many be
included. In the embodiment of FIGS. 1-3, there are six protruding
lugs 42. They have a tapered cylindrical base 46 and a generally
cylindrical upper portion 48 having a diameter of about 1 to 2
inches and a height above the surface of raised portion 44 of about
1 inch, such that they extend substantially entirely across raised
portion 44. Any suitable number and pattern of protruding lugs 42
may be used, depending on the particular design requirements for
combustor housing 10. In the embodiments illustrated herein, there
are a total of six protruding lugs 42. Protruding lugs 42 may be
identical or different in either of their size, shape or function.
In the embodiment of FIGS. 1-3, there is a central protruding lug
50 or indexing lug that is different from protruding lugs 42.
Central protruding lug 50 has a height that is greater than the
other protruding lugs 42 and it is configured to provide an
indexing function for the outlet cover plate 16 through cooperation
with a central index hole 52 located therein. Lug 50 and index hole
52 position outlet cover plate 16 within opening 39, and also
indexes the radial alignment of the protruding lugs 42 and fuel
outlets 40. For example, by rotating outlet cover plate 16 about
lug 50, the center of cylindrical fuel outlets 40 may be aligned
with the center of protruding lugs 42, such that they are
concentrically arranged about longitudinal axis 43 (FIG. 3).
Central protruding lug 50 is configured to extend through central
indexing hole proximate the outer surface of outlet cover plate 16.
In the embodiment of FIGS. 1-3, the other protruding lugs include
radially-spaced, peripheral protruding lugs 42. They are radially
spaced for concentric axial alignment with radially-spaced,
peripheral fuel outlets 40. The number of protruding lugs 42 will
preferably correspond to the number of fuel outlets 40. In the
embodiment of FIGS. 1-3, passageways 54 extend through
radially-spaced, peripheral protruding lugs 42, raised portion 44
and inlet cover plate 12. Passageways 54 may have any suitable
shape and size, including the axially-aligned cylindrical bores
shown that are concentric with fuel outlets 40. Passageways 54 are
configured to receive a fuel conduit 56 for a source of high energy
content fuel, such as diesel fuel, used for ignition of the
combustor and the low BTU content fuel. Referring to FIG. 8, the
fuel supply conduit 56 may be configured to receive a fuel injector
58 for the controlled release of the high energy content fuel which
is in turn connected to a fuel line 60 supplied by a high BTU
content fuel supply pipe 62. Referring again to FIG. 8, where the
high BTU content fuel is diesel fuel, passageway 54 may also
include an air supply conduit 64 to supply necessary combustion air
for combination with and ignition of the diesel fuel. The air
supply conduit 64 is configured for receipt of air from at least
one radially-spaced conduit 66 that extends away from central inlet
22. Conduit 66 opens to central inlet 22 on one end, which in turn
is configured for attachment to supply pipe 24 (FIGS. 7 and 8), and
which in this embodiment is an air supply pipe. On another end,
conduit or conduits 66 open into passageway 54 and are configured
for fluid coupling to air supply conduit 64. This may also include
a plurality of air supply conduits 64 and a corresponding plurality
of radially-spaced fuel conduits 56 in any number, with the number
preferably selected to correspond to the number of fuel outlets 40.
The fuel conduits 56 are preferably located within and spaced from
supply conduit 64, such that the outer surface of fuel conduit 56
and the inner surface of air supply conduit 64 define a space
through which air may be supplied from conduit 66. In a preferred
arrangement, fuel conduit 56 is cylindrical and is concentrically
arranged within air supply conduit 64, such that an annular space
is provided along the length of these conduits for the passage of
air through the space to the firing end. The air supply path and
the high energy content fuel path described preferably include
sealed joints at the various connections described herein.
Passageways 54 may be formed by any suitable manufacturing method,
including drilling.
[0036] Alternately, as shown in the embodiment of FIG. 9, the
protruding lugs 42 may include a passageway 54, or a plurality of
passageways 54, that extends only partially through the thickness
of protruding lug 42 away from plenum 38 so as to intersect and
fluidly couple radially spaced conduit 66. Passageway 54 in this
arrangement is configured to receive a fuel supply conduit (not
shown). The fuel supply conduit in this arrangement may also
include a fuel injector or other gas metering or valving device
(not shown), such as a gas valve. This configuration may be used,
for example, where the central inlet 22 is configured to receive a
high energy content fuel such as natural gas and it is not
necessary to supply air through inlet cover plate 12.
[0037] Combustor housing 10 also includes outlet cover plate 16 on
the outlet side 18 having at least one radially-spaced, peripheral
fuel outlet 40. Outlet cover plate 16 may have any suitable shape
or size, and may be formed from any suitable high temperature
material, including materials that are different from those used
for peripheral sidewall 20 and inlet cover plate 12. In particular,
outlet cover plate 16 may be formed from a material suitable for
use at higher temperatures than those of sidewall 20 and inlet
cover plate 12, since it is located in closer proximity to the
combustion chamber and exposed to higher temperatures. It may be
made using any suitable material adapted to perform at operating
temperatures of up to about 600.degree. C., including various
grades of steel, such as stainless steels, as well as various,
Ni-based, Fe-based, Co-based and other high temperature metal
alloys and materials. In the embodiment of FIGS. 1-3, outlet cover
plate 16 is cylindrical having a diameter of between about 15 to 25
inches, and more particularly about 22 inches, and a thickness of
about 0.5 inches. Forming of the outlet cover plate 16 may be
performed using any suitable manufacturing method, including the
use of machining, grinding and the like. Outlet cover plate 16 is
configured for fixed attachment to sidewall 20 so as to cover and
enclose plenum 38. Referring to FIGS. 1-3, outlet cover plate 16 is
sized for close spaced engagement within opening 39, with the
outlet surface 21 of sidewall 20 proximate opening 39 and the outer
surface of outlet cover plate 16 are substantially flush with one
another. This positioning may be affected by the use of index lug
50 and index hole 52. Further, index lug 50 may have a tapered
base, and the height of the taper may be controlled to also index
the vertical position of outlet cover plate 16 by limiting the
depth to which the plate may be inserted into plenum 39. Further,
indexing may be accomplished by providing corresponding flanges,
such as sidewall flange 45 and outlet cover flange 47, as
illustrated in FIGS. 1 and 3. Once the outlet cover plate 16 has
been placed into opening 39 in the manner described, it is fixed to
peripheral sidewall 20, such as by welding or another suitable
metal joining process.
[0038] Outlet 40 may have any suitable shape or size, and may
include a plurality of fuel outlets 40. More particularly, outlet
40 may have the form of a cylindrical outlet bore having a bore
diameter, by way of a non-limiting example, of about 1 to 3 inches.
Further, in the exemplary embodiment of FIGS. 1-3, there are six
outlets 40. Radially spaced outlet 40, or a plurality of fuel
outlets 40, is configured to receive a supply of low BTU content
fuel gas from the plenum 38 as well as a supply of a high BTU
content fuel from a high BTU content fuel conduit, as further
described herein. Outlet 40, or fuel outlets 40, may also be
adapted to receive air through an air conduit, as further described
herein. Referring to FIGS. 1-3, protruding lug 42 is positioned
proximate to or within the inlet side of outlet 40 so as to form a
restriction which limits the flow of the low BTU content fuel
through outlet 40 by defining a channel 68 or annular space between
them through which the gaseous fuel exiting outlet 40 must flow.
This spacing may be designed in conjunction with consideration of
the various fuel inputs into plenum 38 to provide the desired flow
characteristics (e.g., flow rate) through outlet 40. Outlet 40 may
also include an outlet flange 49 which may be used to seat a
nozzle, as described herein.
[0039] Referring to FIG. 8, a combustor 100 includes combustor
housing 10. Combustor 100 also includes at least one fuel nozzle 70
disposed on outlet cover plate 16 proximate outlet 40. The low BTU
content fuel flowing out of outlet 40 flows through nozzle 70 and
into the combustion chamber (not shown). Fuel nozzle 70 is
generally cylindrical, and adapted to control the flow of fuel into
the combustion chamber, including the fuel flow pattern as the fuel
exits the nozzle 70. Fuel nozzle 70 has a housing end 72 with an
inlet opening 74. Fuel nozzle 70 may be flush mounted on the outer
surface of outlet cover plate 16 with inlet opening 74 disposed
around outlet 40. Alternately, housing end 72 may be adapted for
insertion into outlet 40 and include a mounting flange 76 that
controls the depth to which housing end 72 is inserted by abutting
engagement with outlet flange 49. In this arrangement, housing end
72 of nozzle 70 also serves to affect the channel 68 between the
inlet opening 74 of nozzle proximate housing end 72 and the outer
end of protruding lug 42. Nozzle 70 may be disposed on outlet cover
plate 16 by any suitable means of attachment, including welding,
such as by use of a circumferential weld. An ignition source such
as a spark igniter, including a spark plug, may be positioned
proximate nozzle 70 for ignition of the fuel exiting the nozzle
into the combustion chamber (not shown). Nozzle or nozzles 70 have
a generally cylindrical nozzle bore 77 and a nozzle end 78. Nozzle
end 78 may include a restriction 80 that is used to control the
flow of the low BTU content fuel through the nozzle 70.
[0040] As shown in FIG. 8, both the high BTU content fuel conduit
56 and air supply conduit 64, in the form of a fuel injector,
extend axially away from outlet cover plate 16 toward nozzle end
78. Particularly, fuel injector 58 may extend within nozzle bore 77
to a position proximate restriction 80. The radial spacing 82
between restriction 80 and fuel injector 58 defines a outlet
spacing or channel 82 through which the low BTU content fuel must
pass in order to exit nozzle 70 and combustor housing 10. This
outlet spacing 82 defines a nozzle orifice to control the flow of
fuel from the nozzle. Spacing 82 may be designed to achieve the
desired flow characteristics from the combustor, and may be an
annular spacing or channel as shown in FIG. 8. The spacing 82 is an
unobstructed 360.degree. flow path or channel. Such a flow path is
desirable because it maintains a uniform flow pattern of the fuel
exiting the nozzle and reduces or eliminates restrictions in the
flow path in the space between the injector and nozzle bore along
the length of the nozzle.
[0041] A second exemplary embodiment of a combustor housing 10' is
illustrated in FIG. 4. This embodiment includes the same elements
as discussed above with respect to the embodiment of FIG. 3 in a
somewhat different configuration, with the changes discussed
further below. In the embodiment of FIG. 4, the outlet cover plate
16' has a larger size, such as a larger diameter such that it
extends at least partially, and more preferably fully, across the
outlet surface of sidewall 20', rather than being inserted into
opening 39'. As compared to the embodiment of FIG. 3, the thickness
of the sidewall 20' may be somewhat thinner so that the protruding
lugs 42' are located with respect to the fuel outlets 40', as
described herein. The central lug 50 of FIG. 3 is not required in
this embodiment hence, central lug 50 may be omitted, thereby
opening up the central portion of plenum 38' and providing more
usable volume within plenum 38'. Alternately, central lug 50 may be
replaced with a central protruding lug 42' (not shown) and
corresponding nozzle 70 (not shown), such that a central outlet
(not shown) may also be incorporated into outlet cover plate 16'.
Outlet cover plate 16' may be attached to peripheral sidewall 20'
by any suitable attachment means, such as a plurality of
radially-spaced threaded bolts, or a circumferential weld, or the
like. Likewise, combustor housing 10' may be made from the same
materials as those described for combustor housing 10 of FIG. 3,
and may incorporate various pipes, flanges, nozzles, fuel conduits,
fuel injectors and other components of the types and in the manner
described with reference to combustor housing 10' to form a
combustor.
[0042] A third exemplary embodiment of a combustor housing 10'' is
illustrated in FIG. 5. This embodiment includes the same elements
as discussed above with respect to the embodiment of FIG. 3 in a
somewhat different configuration, with the changes discussed
further below. In the embodiment of FIG. 5, the outlet cover plate
16'' and fuel outlets 40'' are formed integrally with sidewall
20''. It is believed that this arrangement may provide greater
structural rigidity to the combustion side of combustor housing
during operation of the combustor and turbine, and removes any
possibility of failures or other performance issues associated with
the attachment means, such as a weld, used to attach the outlet
cover plate 16 in the embodiment of FIG. 3 during operation.
Sidewall 20'' will similarly be altered to provide an opening 39''
similar in size to that of opening 39 of FIG. 3, but located on the
opposite end of sidewall 20''. In the embodiment of FIG. 5, the
inlet cover plate 12'' is manufactured as a separate component and
attached to sidewall 20'' as shown. Otherwise, inlet cover plate
12'' may include all of the other features included in inlet cover
plate 12 of FIG. 3, such as protruding lugs 42'' raised portion
44'', central protruding lug 50'', radially-spaced, peripheral fuel
inlets 30'', central inlet 22'' and the various conduits and
passageways described therein. Inlet cover plate 12'' may be
inserted into opening 39'' and attached in a manner analogous to
that described with regard to outlet cover plate 16 of FIG. 3.
Likewise, combustor housing 10' may be made from the same materials
as those described for combustor housing 10, and may incorporate
various pipes, flanges, nozzles, fuel conduits, fuel injectors and
other components of the types and in the manner described with
reference to combustor housing 10'.
[0043] A fourth exemplary embodiment of a combustor housing 10'''
is illustrated in FIG. 6. This embodiment includes the same
elements as discussed above with respect to the embodiment of FIG.
5 in a somewhat different configuration, with the changes discussed
further below. In the embodiment of FIG. 6, the inlet cover plate
12''' has a larger size, such as a larger diameter such that it
extends at least partially, and more preferably fully, across the
inlet surface 23''' of sidewall 20''' rather than being inserted
into opening 39'''. The central lug 50'' is not required in this
embodiment hence, central lug 50'' of FIG. 5 may be omitted,
thereby opening up the central portion of plenum 38''' and
providing more usable volume within plenum 38'''. Alternately,
central lug 50'' of the embodiment of FIG. 5 may be replaced with a
central protruding lug 42''' (not shown), such that a central
outlet (not shown) and associated nozzle (not shown) may also be
incorporated into outlet cover plate 16'''. Inlet cover plate 12'''
may be attached to peripheral sidewall 20''' by any suitable
attachment means, such as a plurality of radially-spaced threaded
bolts, or a circumferential weld, or the like.
[0044] FIG. 10 illustrates fuel inlet 30 of FIG. 3 as it opens into
plenum 38. The mixing area created by plenum 38 advantageously
affords a large volume for receipt of the substantial volumetric
input of low BTU content fuel gas at high flow rates from multiple
fuel inlets 30. This arrangement is particularly advantageous in
that is affords a low pressure drop per individual fuel inlet 30,
and thus a low total pressure drop associated with the sum of all
of the fuel inlets 30. FIG. 11 illustrates the inlet arrangement
associated with fuel inlet 30' as shown in FIG. 4. In this
embodiment, outlet cover plate 16' covers the entire outlet surface
21' of sidewall 20'. This inlet configuration is advantageous
because the center portion of plenum 38' is open due to the absence
of a central lug which provides a more open configuration of the
center portion of plenum 38' for better mixing and a larger plenum
38' volume as compared, for example, to plenum 38. Further, it
permits outlet cover plate 16' to be bolted to the peripheral
sidewall 20' using a plurality of threaded bolts or similar
fasteners. The elimination of the central lug and bolted attachment
provides another advantage of this embodiment, namely the
elimination of two welds, including the weld associated with the
center lug, and the weld used to attach outer cover plate to
peripheral sidewall, thereby reducing cost and complexity.
[0045] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
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