U.S. patent application number 12/241623 was filed with the patent office on 2010-04-01 for systems and methods for facilitating varying size coal pipes for a pulverized coal burner.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Bob Frato, Donald K. Morrison, David Kelly Moyeda, Robert W. Waltz, Wei Zhou.
Application Number | 20100081102 12/241623 |
Document ID | / |
Family ID | 41429154 |
Filed Date | 2010-04-01 |
United States Patent
Application |
20100081102 |
Kind Code |
A1 |
Morrison; Donald K. ; et
al. |
April 1, 2010 |
SYSTEMS AND METHODS FOR FACILITATING VARYING SIZE COAL PIPES FOR A
PULVERIZED COAL BURNER
Abstract
Embodiments of the invention can include systems and methods for
facilitating varying coal pipes for a pulverized coal burner. In
one embodiment, a method for improving operation of a pulverized
coal burner comprising at least one burner comprising at least one
coal pipe having an inner diameter, and an outer diameter. The
method can include installing at least one sleeve or at least one
liner within the coal pipe between the inner and outer diameter of
the coal pipe, wherein velocity of a primary air and pulverized
coal mixture is increased in an upstream portion of the coal pipe.
The method can also include reducing the at least one sleeve or
liner, wherein velocity of the primary air and pulverized coal
mixture is reduced in a downstream portion of the coal pipe.
Inventors: |
Morrison; Donald K.;
(Clinton, OH) ; Zhou; Wei; (Foothill Ranch,
CA) ; Frato; Bob; (Stilwell, KS) ; Moyeda;
David Kelly; (Laguna Hills, CA) ; Waltz; Robert
W.; (Canton, OH) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
41429154 |
Appl. No.: |
12/241623 |
Filed: |
September 30, 2008 |
Current U.S.
Class: |
431/354 ;
110/263; 110/347 |
Current CPC
Class: |
C21C 5/5217 20130101;
F27D 99/0003 20130101; Y02P 10/216 20151101; Y02P 10/20 20151101;
F23D 17/00 20130101; F27D 99/0033 20130101; F23D 1/00 20130101 |
Class at
Publication: |
431/354 ;
110/347; 110/263 |
International
Class: |
F23D 14/00 20060101
F23D014/00; F23D 1/00 20060101 F23D001/00 |
Claims
1. A method for improving operation of a pulverized coal burner
comprising at least one coal pipe having an inner diameter, and an
outer diameter, the method comprising: installing at least one
sleeve or at least one liner within the coal pipe between the inner
and outer diameter of the coal pipe, wherein velocity of a primary
air and pulverized coal mixture is increased in an upstream portion
of the coal pipe; and reducing the at least one sleeve or liner,
wherein velocity of the primary air and pulverized coal mixture is
reduced in a downstream portion of the coal pipe.
2. The method of claim 1, wherein the at least one sleeve or at
least one liner terminates within about 10 to about 20 inches (25.4
to 50.8 cm) from a downstream end of the burner.
3. The method of claim 1, wherein the at least one sleeve or at
least one liner comprises a ceramic, metal, or a high temperature
resistant material.
4. The method of claim 1, wherein the at least one sleeve or at
least one liner comprises at least one transition ramp or device to
prevent flow recirculation.
5. The method of claim 1, wherein the at least one sleeve or at
least one liner comprises a plurality of sleeve or liner components
or sections.
6. The method of claim 1, wherein a thickness of the at least one
sleeve or at least one liner is determined by the equations: ds =
do 2 ( V 2 - V 1 ) + di 2 V 1 V 2 Thickness = ds - di 2
##EQU00002## wherein, ds is an outer diameter of the at least one
sleeve, do is an outer diameter of the coal pipe, di is an inner
diameter of the coal pipe, V2 is a target velocity of the primary
air and pulverized coal mixture within the upstream portion of the
coal pipe, and V1 is a target exit velocity of the primary air and
pulverized coal mixture.
7. The method of claim 1, wherein the at least one sleeve or at
least one liner is mounted coaxially and in close proximity to an
inner diameter, of at least one coal pipe, or coaxially and in
close proximity to an outer diameter, of the at least one coal
pipe.
8. An apparatus for improving operation of a pulverized coal burner
comprising at least one coal pipe having an inner diameter, and an
outer diameter, the apparatus comprising: at least one sleeve or at
least one liner installed within the coal pipe between the inner
and outer diameter of the coal pipe, wherein velocity of a primary
air and pulverized coal mixture is increased in an upstream portion
of the coal pipe; and wherein the at least one sleeve or at least
one liner is reduced in a downstream portion of the coal pipe to
reduce the velocity of the primary air and pulverized coal
mixture.
9. The apparatus of claim 8, wherein the at least one sleeve or at
least one liner terminates within about 10 to about 20 inches (25.4
to 50.8 cm) from a downstream end of the burner.
10. The apparatus of claim 8, wherein the at least one sleeve or at
least one liner comprises a ceramic, a metal, or a high temperature
resistant material.
11. The apparatus of claim 8, wherein the at least one sleeve or at
least one liner comprises at least one transition ramp or device to
prevent flow recirculation.
12. The apparatus of claim 8, wherein the at least one sleeve or at
least one liner comprises a plurality of sleeve or liner components
or sections.
13. The apparatus of claim 8, wherein a thickness of the at least
one sleeve or at least one liner is determined by the equations: ds
= do 2 ( V 2 - V 1 ) + di 2 V 1 V 2 Thickness = ds - di 2
##EQU00003## wherein, ds is an outer diameter of the at least one
sleeve, do is an outer diameter of the coal pipe, di is an inner
diameter of the coal pipe, V2 is a target velocity of the primary
air and pulverized coal mixture within the coal pipe, and V1 is a
target exit velocity of the primary air and pulverized coal
mixture.
14. A combustion system comprising: at least one burner starter; at
least one core pipe, wherein the at least one burner starter is
mounted within at least one core pipe; at least one coal pipe
having an inner diameter and an outer diameter; at least one sleeve
or at least one liner between the coal pipe inner diameter, and
outer diameter, wherein the velocity of a primary air and
pulverized coal mixture is increased in an upstream portion of the
coal pipe, and wherein velocity of the primary air and pulverized
coal mixture is reduced in a downstream portion of the coal
pipe.
15. The system of claim 14, wherein the at least one sleeve or at
least one liner terminates within about 10 to about 20 inches (25.4
to 50.8 cm) from a downstream end of the burner.
16. The system of claim 14, wherein the at least one sleeve or at
least one liner comprises a ceramic, metal, or a high temperature
resistant material.
17. The system of claim 14, wherein the at least one sleeve or at
least one liner comprises at least one transition ramp or device to
prevent flow recirculation.
18. The system of claim 14, wherein the at least one sleeve or at
least one liner comprises a plurality of sleeve or liner components
or sections.
19. The system of claim 14, wherein a thickness of the at least one
sleeve or at least one liner is determined by the equations; ds =
do 2 ( V 2 - V 1 ) + di 2 V 1 V 2 Thickness = ds - di 2
##EQU00004## wherein, ds is an outer diameter of the at least one
sleeve, do is an outer diameter of the coal pipe, di is an inner
diameter of the coal pipe, V2 is a target velocity of the primary
air and pulverized coal mixture within the coal pipe, and V1 is a
target exit velocity of the primary air and pulverized coal mixture
at the burner.
20. The system of claim 14, wherein the at least one sleeve or at
least one liner is mounted coaxially and in close proximity to an
outer diameter, of the at least one coal pipe, or coaxially and in
close proximity to an inner diameter, of the at least one coal
pipe.
Description
FIELD OF INVENTION
[0001] The invention generally relates to pulverized coal burners,
and more particularly relates to systems and methods for
facilitating varying size coal pipes for a pulverized coal
burner.
BACKGROUND OF THE INVENTION
[0002] Pulverized coal burners are utilized in combustion and heat
transfer processes within utility and industrial boiler furnaces of
coal-fired power plants and other power generating facilities. In a
typical furnace, raw coal is crushed into small pieces, conveyed to
coal feed hoppers, pulverized into a very fine powder, mixed with
primary air, and blown through a furnace coal pipe, wherein the
fine coal is directed to a coal burner where the mixture of primary
air and coal is ignited upon introduction to the furnace. The
subsequent combustion of the primary air and coal mixture heats the
furnace to generate steam used for power generation and other plant
purposes.
[0003] Extracting maximum energy from pulverized coal while
minimizing environmental pollutants sometimes requires careful
control of the fuel delivery and combustion process. Excess
nitrogen oxides (NOx) can be produced at the burner when the flame
is not carefully controlled, or when it becomes unstable, as is
often the case when the air/coal mixture velocity is too high when
introduced at the burner end. However, the air/coal mixture
velocity must be high enough within the coal delivery pipe so that
the coal particles do not fall out of the air and collect in or
otherwise clog the coal delivery pipe. These two opposing
requirements (high air/coal mixture velocity in the coal delivery
pipe and low air/coal mixture velocity at the burner end) present a
difficult challenge for boiler and service engineers, particularly
as furnace output and/or air/coal mixture velocity requirements
change.
[0004] Many existing pulverized coal burners were designed with
coal pipe geometries tuned to a certain air/fuel injection and
velocity rate. As new industrial pollution limits, process
refinements, etc. are implemented, existing pulverized coal burners
may not be suitable to maintain or otherwise attain certain
upstream and downstream air/coal mixture velocity requirements, and
new coal burner components, such as different sized coal delivery
pipes, may need to be installed to stabilize the burner flame and
eliminate coal dropout. Such installations can be time consuming
and expensive.
[0005] Therefore, a need exists for systems, methods, and apparatus
for facilitating varying size coal pipes for a pulverized coal
burner.
[0006] A further need exists for systems, methods, and apparatus to
modify or retrofit existing coal pipes as injection speeds or other
system parameters are changed to meet new requirements.
[0007] A further need exists for systems, methods, and apparatus
for improving operation of a pulverized coal burner.
BRIEF DESCRIPTION OF THE INVENTION
[0008] Embodiments of the invention can include systems and methods
for facilitating varying size coal pipes for a pulverized coal
burner. Other embodiments of systems, apparatuses and methods for
improving the operation of a pulverized a coal burner can also be
provided. Certain embodiments of the invention can utilize existing
parts of a coal pipe together with newly added sleeves, liners
and/or transition ramps to meet target air/coal mixture velocities
within the coal pipe and at the burner without having to replace
the entire coal pipe assembly.
[0009] In one embodiment, a method for improving operation of a
pulverized coal burner can include at least one coal pipe having an
inner diameter, and an outer diameter. In addition, the method can
include installing at least one sleeve or at least one liner within
the coal pipe between the inner and outer diameter of the coal
pipe, wherein velocity of a primary air and pulverized coal mixture
is increased in an upstream portion of the coal pipe. The method
can also include reducing the at least one sleeve or liner, wherein
velocity of the primary air and pulverized coal mixture is reduced
in a downstream portion of the coal pipe.
[0010] In one embodiment, an apparatus for improving operation of a
pulverized coal burner can include at least one coal pipe having an
inner diameter, and an outer diameter. The method can include
installing at least one sleeve or at least one liner within the
coal pipe between the inner and outer diameter of the coal pipe,
wherein velocity of a primary air and pulverized coal mixture is
increased in an upstream portion of the coal pipe. The method can
also include reducing the at least one sleeve or at least one
liner, wherein velocity of the primary air and pulverized coal
mixture is reduced in a downstream portion of the coal pipe.
[0011] In one embodiment, a combustion system can be provided. The
combustion system can include at least one burner starter, at least
one core pipe, wherein the at least one burner starter is mounted
within at least one core pipe. The system can include at least one
coal pipe having an inner diameter and an outer diameter. The
system can further include at least one sleeve or at least one
liner between the coal pipe inner diameter and outer diameter,
wherein the velocity of a primary air and pulverized coal mixture
is increased in an upstream portion of the coal pipe, and wherein
velocity of the primary air and pulverized coal mixture is reduced
in a downstream portion of the coal pipe.
[0012] Other embodiments and aspects of embodiments of the
invention will become apparent from the following description taken
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Having thus described the invention in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
[0014] FIG. 1 depicts an example of a conventional pulverized coal
burner.
[0015] FIG. 2 shows an end view of an example pulverized coal
burner in accordance with an embodiment of the invention.
[0016] FIG. 3 shows an end view of an example pulverized coal
burner in accordance with an embodiment of the invention.
[0017] FIG. 4 shows a side view of an example pulverized coal
burner in accordance with an embodiment of the invention.
[0018] FIG. 5 shows an end view of an example pulverized coal
burner in accordance with an embodiment of the invention.
[0019] FIG. 6 illustrates a sleeve embodiment of the example
pulverized coal burner shown in FIG. 2 in accordance with an
embodiment of the invention
[0020] FIG. 7 illustrates a liner embodiment of the example
pulverized coal burner shown in FIG. 5 in accordance with an
embodiment of the invention.
[0021] FIG. 8 depicts an example transition ramp for a pulverized
coal burner in accordance with an embodiment of the invention.
[0022] FIG. 9 depicts an embodiment of a pulverized coal burner in
accordance with an embodiment of the invention.
[0023] FIG. 10 illustrates an example apparatus and system for
facilitating varying coal pipes for a pulverized coal burner.
[0024] FIG. 11 illustrates an example method in accordance with an
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Embodiments of the invention will now be described more
fully hereinafter with reference to the accompanying drawings. This
invention may, however be embodied in many different forms and
should not be construed as limited to the embodiment set forth
herein; rather, embodiments are provided so that this disclosure
will be thorough and complete, and will convey the scope of the
invention.
[0026] As used herein, the term "sleeve" refers to a structure that
is adjacent to, borders, surrounds, mounts to, or is otherwise
attached to an outer portion of a core pipe, such as 112 in FIG. 1.
One example of a sleeve is shown as 206 in the cross-section 200 of
FIG. 2, and can include a sleeve diameter (ds). In some
embodiments, a sleeve may be a single piece or comprised of
multiple pieces.
[0027] As used herein, the term "liner" refers to a structure that
is adjacent to, borders, mounts to, or is otherwise attached to an
inner portion of a coal pipe, such as 104 in FIG. 1. One example of
a liner is shown as 504 in FIG. 5 and 702 in FIG. 7, and can
include a liner inside diameter (dl). In some embodiments, a liner
may be a single piece or comprised of multiple pieces.
[0028] As used herein, the term "fuel mixture" refers to a mixture
of primary air and pulverized coal. Other embodiments may include
mixtures of primary air and other fuel types.
[0029] As used herein, the term "upstream" refers to a section of a
coal pipe nearest to an inlet duct, such as 110 in FIG. 1, and the
term "downstream" refers to a section of a coal pipe nearest to an
ignitor and flame end, such as 114 in FIG. 1, where a fuel mixture
exits the coal pipe, such as 104 in FIG. 1.
[0030] FIG. 1 depicts an example of a conventional pulverized coal
burner. The pulverized coal burner 100 is configured with a flame
stabilizer 102 at a downstream end of a coal pipe 104, and a splash
plate 106 at an opposing or upstream end of the coal pipe 104. The
pulverized coal burner 100 also includes a mounted gas gun and tube
assembly 108, an inlet duct 110, and a core pipe 112. The gas gun
and tube assembly 108 is coaxially mounted inside a core pipe 112,
and both the gas gun and tube assembly 108 and core pipe 112 are
coaxially mounted within the coal pipe 104. A mixture of primary
air and pulverized coal, or fuel mixture, enters the burner 100
through the inlet duct 110 adjacent to the upstream end of the
burner 100. The splash plate 106 helps re-direct the primary air
and pulverized coal mixture, or fuel mixture, through the coal pipe
104 towards the downstream end of the burner 100, through the flame
stabilizer 102 adjacent to the downstream end, and to the ignitor
and flame region 114, which is typically adjacent to a furnace.
[0031] Embodiments of a pulverized coal burner in accordance with
the invention are shown with respect to FIGS. 2-11. Certain
embodiments of the invention can provide improvements in the
operation of a pulverized coal burner. In one such embodiment, one
or more sleeves and/or liners can be installed within an associated
coal pipe to increase velocity of the primary air/pulverized coal
mixture, or fuel mixture, in an upstream portion of the coal pipe
while simultaneously reducing velocity of the fuel mixture at an
opposing end or downstream end of the coal pipe. The increased
velocity at the upstream portion of the coal pipe tends to reduce
coal dropout, while the reduced velocity at the downstream end
tends to improve flame stability and can suppress excess production
of nitrogen oxides (NOx).
[0032] To illustrate example principles for improving operation of
a pulverized coal burner in accordance with embodiments of the
invention, FIGS. 2-5 illustrate certain geometries associated with
components of various pulverized coal burners in accordance with
embodiments of the invention.
[0033] FIG. 2 shows an end view of a pulverized coal burner in
accordance with an embodiment of the invention. The burner
cross-section 200 is annular-shaped and defined by a coal pipe 202
and a coaxially positioned core pipe 204 with a sleeve 206 adjacent
to an outer portion of the core pipe 204. An outer diameter (do) of
the cross-section 200 is defined by a distance between at least two
inner portions of the coal pipe 202, and an inner diameter (di) of
the cross-section is defined by a distance between at least two
outer portions of the core pipe 204. A sleeve diameter (ds) is
defined by a distance between at least two outer portions of the
sleeve 206.
[0034] FIG. 3 shows an end view of a pulverized coal burner in
accordance with an embodiment of the invention. FIG. 3 represents
reducing the at least one sleeve or liner, wherein velocity of the
primary air and pulverized coal mixture is reduced in a downstream
portion of the coal pipe. The term "reducing" can mean removing,
omitting, or making less thick, and therefore, reducing the sleeve
or liner in a portion of the coal pipe increases the volume of the
coal pipe and reduces the velocity of the primary air and
pulverized coal mixture in that section of the coal pipe. The
burner cross-section 300 is annular-shaped defined by a coal pipe
302 and a coaxially positioned core pipe 304. An outer diameter
(do) of the cross-section 300, similar to the outer diameter (do)
in FIG. 2, is defined by a distance between at least two inner
portions of the coal pipe 302, and an inner diameter (di) of the
cross-section 300, similar to the inner diameter (di) in FIG. 2, is
defined by a distance between at least two outer portions of the
core pipe 304.
[0035] FIG. 5 shows an end view of a pulverized coal burner in
accordance with an embodiment of the invention. The burner
cross-section 500 is annular-shaped defined by a coal pipe 502 and
a coaxially positioned core pipe 506 with a liner 504 adjacent to
an inner portion of the coal pipe 502. An outer diameter (do) of
the cross-section 500, similar to the outer diameter (do) in FIGS.
2 and 3, is defined by a distance between at least two inner
portions of the coal pipe 502, and an inner diameter (di) of the
cross-section 500, similar to the inner diameter (di) in FIGS. 2
and 3, is defined by a distance between at least two outer portions
of the core pipe 506. A liner diameter (dl) is defined by a
distance between at least two inner portions of the liner 504. In
one embodiment, the core pipe 506 may be absent from the
arrangement, and thus the coal pipe 502 would be coreless. In that
embodiment, the cross-section would have a similar outer diameter
(do) as the outer diameter (do) in FIG. 3, but the inner diameter
(di) would be zero.
[0036] Referring to FIGS. 4 and 6, an ideal velocity V2 of a fuel
mixture within the coal pipe 404, 604, or at the upstream end, may
differ from an ideal velocity V1, Vexit at the burner end adjacent
to the ignitor and flame region 606, or at the downstream end 406,
due to opposing requirements. For example, a relatively high fuel
mixture velocity in the coal pipe 404, 604 can help prevent or
otherwise minimize coal or other fuel particulate from "falling out
of the air" and clogging the coal pipe 404, 604. On the other hand,
a relatively low fuel mixture velocity at a downstream end adjacent
burner exit 606 may be needed to control flame instability, and to
reduce the generation of nitrogen oxides (NOx).
[0037] The velocities V1, V2 of the fuel mixture within the coal
pipe 404 is typically determined by the flow rate, the flow
temperature, and the cross-sectional area within the coal pipe 404.
For a pulverized coal burner in accordance with embodiments of the
invention, injection flow rate and flow temperature are usually
fixed. Therefore, the flow area multiplied by the flow velocity is
maintained relatively constant.
[0038] FIGS. 4 and 6 illustrate respective side views of an example
pulverized coal burner 400, 600 in accordance with an embodiment of
the invention. If a sleeve 402, 602 is installed in a portion of
the coal pipe 404, 604, the cross-section 200 of the coal pipe 404,
604 can be defined by an annulus with an outer diameter (do) and an
inner (sleeve) diameter (ds), as depicted in FIG. 2. Towards the
downstream end 406, 606 of the burner 400, 600, where the sleeve
402, 602 is reduced or is omitted, the cross-section 300 of the
coal pipe 404, 604 can be defined by an annulus with an outer
diameter (do) and an inner diameter (di), where the inner diameter
(di) is typically defined by the outer diameter of the core pipe
304, as depicted in FIG. 3.
[0039] With reference to FIG. 4, given a target exit velocity V1,
the radial thickness of the sleeve 402 needed to produce a target
velocity V2 within an upstream portion or end 406 of the coal pipe
404 can be calculated using the following equations (1), (2), and
(3).
.pi. [ ( do 2 ) 2 - ( ds 2 ) 2 ] V 2 = .pi. [ ( do 2 ) 2 - ( di 2 )
2 ] V 1 ( 1 ) ds = do 2 ( V 2 - V 1 ) + di 2 V 1 V 2 ( 2 )
Thickness Sleeve = ds - di 2 ( 3 ) ##EQU00001##
[0040] In one example, V1=50 ft/s (15.2 m/s), V2=60 ft/s (18.3
m/s), do=20 inches (50.8 cm), di=10 inches (25.4 cm). From equation
(2), a sleeve diameter (ds) can be calculated to be approximately
12.25 inches (31.1 cm). A sleeve thickness calculated from equation
(3) can be calculated to be approximately 1.125 inches (2.86 cm).
Using some or all of the equations (1), (2), and (3), one can
perform a similar calculation to determine geometric requirements
for a liner embodiment, as shown in FIGS. 5 and 7.
[0041] Embodiments of the invention can include any combination of
at least one sleeve and/or at least one liner. In the example
pulverized coal burner 600 shown in FIG. 6, a sleeve 602 is mounted
to and surrounds the core pipe 608. FIG. 7, in contrast, shows an
example coal burner 700 with a liner 702 mounted to the interior
portion of the coal pipe 704. Any number of embodiments can exist
where the fuel mixture velocity is controlled or otherwise affected
by any combination of liner and/or sleeve pieces, sections, or
components. Depending on flow conditions within the associated coal
pipe 604, 704, a sleeve and/or liner can be installed between the
inner portion of the coal pipe 604, 704 and the outer portion of
the core pipe 608, 708, and close proximity to or otherwise in
contact with either or both.
[0042] In this manner, the relative exit velocity (Vexit) can be
reduced, thereby reducing or minimizing flow recirculation and
turbulence of the fuel mixture at the downstream end 606, 706 of
the burner 600, 700, which can stabilize burner combustion
characteristics, i.e., the burner flame. If the sleeve and/or liner
abruptly ends, for example, within approximately 6 inches (15.2 cm)
of the downstream end 606, 706 of the burner 600, 700, a relatively
higher probability may exist that unwanted turbulence will be
generated near or adjacent to the downstream end 606, 706 of the
burner 600, 700, thereby resulting in possible flow recirculation
and/or flame instability.
[0043] FIG. 8 depicts an example transition ramp for a pulverized
coal burner in accordance with an embodiment of the invention. To
minimize or otherwise reduce turbulence generated near or adjacent
to an downstream end of a burner, at least one burner embodiment
800 includes a transition sleeve, liner, or ramp 802, as shown in
FIG. 8. In this manner, turbulence caused by velocity
discontinuities in the coal pipe can be minimized. In one
embodiment, a transition ramp, similar to 802 as shown in FIG. 8,
can also be applied in a similar fashion to a liner, for example,
the liner 702 for burner 700 of FIG. 7.
[0044] One pulverized coal burner embodiment is described by way of
FIG. 9, which depicts a burner 900 with a coreless coal pipe and a
liner 902 mounted adjacent to the inner portion of the coal pipe
904. In this embodiment, the respective fuel mixture upstream and
exit velocities, V1 and V2, are related to the respective coal pipe
and liner diameters, do and dl, by the equation:
.pi.do.sup.2V1=.pi.dl.sup.2V2 (4)
[0045] where again, a transition ramp element or feature, similar
to 802 of FIG. 8, may be applied to the liner 902 shown to reduce
or otherwise minimize turbulence and flow recirculation.
[0046] In one embodiment, a sleeve and/or liner can be installed in
multiple corresponding and adjacent sections to accommodate
existing obstructions that would otherwise prevent or hinder the
installation of a single or single-piece sleeve and/or liner. As
shown in FIG. 10, one embodiment can include multiple sleeve pieces
1002, 1004, 1008 which can mount adjacent to the core pipe 1012 to
accommodate any number of stabilizing or support members 1006 which
may also mount to the core pipe 1012. Note that a coal pipe is not
shown in FIG. 10, but after the sleeve sections are installed, the
outer coal pipe would coaxially mount to the splash plate 1010 to
complete a burner assembly similar in structure to the burner 600
in FIG. 6.
[0047] FIG. 11 illustrates an example method in accordance with an
embodiment of the invention. Other method embodiments can include
fewer or greater elements, and may have alternate arrangements in
accordance with the invention.
[0048] The method 1100 begins at block 1102, wherein at least one
sleeve or at least one liner can be installed within the coal pipe
between the inner and outer diameter of the coal pipe, wherein
velocity of a primary air and pulverized coal mixture is increased
in an upstream portion of the coal pipe.
[0049] Block 1102 is followed by block 1104, wherein the at least
one sleeve or liner can be reduced, wherein velocity of the primary
air and pulverized coal mixture is reduced in a downstream portion
of the coal pipe.
[0050] The method 1100 ends at block 1104.
[0051] The methods, systems and apparatus disclosed herein are by
way of example only, and other methods in accordance with the
embodiments of the invention can include other elements or steps,
including fewer or greater numbers of elements or steps than the
example methods described herein as well as various combinations of
these or other elements.
[0052] While the above description contains many specifics, these
specifics should not be construed as limitations on the scope of
the invention, but merely as exemplifications of the disclosed
embodiments. Those skilled in the art will envision many other
possible variations that are within the scope of the invention.
* * * * *