U.S. patent application number 12/737414 was filed with the patent office on 2011-07-28 for method and device for igniting and operating burners when gasifying carbon-containing fuels.
This patent application is currently assigned to UHDE GmbH. Invention is credited to Frank Dziobek, Johannes Kowoll, Eberhard Kuske, Hubert Werneke.
Application Number | 20110183275 12/737414 |
Document ID | / |
Family ID | 41376369 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110183275 |
Kind Code |
A1 |
Kuske; Eberhard ; et
al. |
July 28, 2011 |
METHOD AND DEVICE FOR IGNITING AND OPERATING BURNERS WHEN GASIFYING
CARBON-CONTAINING FUELS
Abstract
With a method and a device for igniting and operating burners
when gasifying a carbon-containing fuel using at least two
gasification burners, start of the pressure gasification with short
start times is made possible, at high pressures, without prior
inertization of the gas space, while avoiding continuous fuel gas
consumption in the pilot burner or ignition burner and also
protecting stationary ignition burners against contamination by
configuring one gasification burner as a start-up burner, which is
ignited by at least one pilot burner using an electrical ignition
device. A combustible gas mixture including a fuel gas and
oxygen-containing gas is ignited by the pilot burner, in the
start-up burner. After ignition of the start-up burner, at least
one further gasification burner is ignited by this burner. The
start-up burner is operated further as one of the gasification
burners of the carbon-containing fuel via a change in medium.
Inventors: |
Kuske; Eberhard; (Soest,
DE) ; Kowoll; Johannes; (Bochum, DE) ;
Werneke; Hubert; (Dortmund, DE) ; Dziobek; Frank;
(Muehlheim, DE) |
Assignee: |
UHDE GmbH
Dortmund
DE
|
Family ID: |
41376369 |
Appl. No.: |
12/737414 |
Filed: |
July 7, 2009 |
PCT Filed: |
July 7, 2009 |
PCT NO: |
PCT/EP2009/004894 |
371 Date: |
March 25, 2011 |
Current U.S.
Class: |
431/3 ; 431/254;
431/6 |
Current CPC
Class: |
Y02T 50/677 20130101;
C01B 2203/1604 20130101; C01B 2203/142 20130101; C01B 3/363
20130101; C10J 2200/152 20130101; C01B 3/32 20130101; C10J
2300/1223 20130101; F23D 2900/00014 20130101; F23N 5/08 20130101;
F23N 5/02 20130101; F23D 23/00 20130101; F23D 1/00 20130101; F23N
5/12 20130101; C10J 3/506 20130101; F23D 14/26 20130101; Y02T 50/60
20130101; F23N 5/14 20130101 |
Class at
Publication: |
431/3 ; 431/6;
431/254 |
International
Class: |
F23N 5/26 20060101
F23N005/26; F23N 5/00 20060101 F23N005/00; F23Q 7/10 20060101
F23Q007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2008 |
DE |
10 2008 033 096.5 |
Claims
1. Method for ignition and for operation of burners in the
gasification of a fuel that contains carbon, using at least two
gasification burners, wherein one of the gasification burners is
configured as a start-up burner, for the ignition of which at least
one pilot burner serves, which is ignited by way of an electrical
ignition device, whereby a combustible gas mixture composed of a
fuel gas and gas that contains oxygen is ignited by the pilot
burner, in the start-up burner, whereby after ignition of the
start-up burner, at least one further gasification burner is
ignited by this burner, and the start-up burner is operated further
as one of the gasification burners of the fuel that contains
carbon, by means of a change in medium.
2. Method according to claim 1, wherein after ignition of the
start-up burner, the pilot burner has a gas mixture applied to it
that contains CO.sub.2 and/or steam and/or oxygen and participates
in the gasification reactions, to prevent clogging.
3. Method according to claim 1, wherein the pilot burner is first
ignited at less than 50% of the power of the gasification burner
being operated as a gas burner, and at an oxygen excess number of
0.8 to 1.2.
4. Method according to claim 1, wherein in order to accelerate
ignition of the mixture that contains oxygen in the gasifier, the
pilot burner has a fuel excess/oxygen excess number<0.8 applied
to it.
5. Method according to claim 1, wherein the flame of the pilot
burner is monitored and the ignition element of the pilot burner is
shut off when the flame is recognized.
6. Method according to claim 1, wherein an ionization flame monitor
is used to monitor the flame of the pilot burner, whereby the
ignition element is used as an electrode.
7. Method according to claim 5, wherein an optical flame monitor is
used, whereby the optical signal is passed to a detector by way of
a lens and a light guide.
8. Method according to claim 5, wherein the change in the
electrical resistance of the ignition element is used to monitor
the flame of the pilot burner.
9. Device (1) for carrying out the method according to claim 1,
wherein the pilot burner (2) is equipped with a centric nozzle head
(3), which is surrounded by a burner pipe (7), which projects
beyond the nozzle head (3) in the flow direction of the fuel gas,
whereby at least one electrical ignition device (9) is provided
within the burner pipe space (8), and a reduction in cross-section
(11) of the burner pipe is provided behind that, in the flow
direction.
10. Device according to claim 9, wherein at least one flame
monitoring element (13) is assigned to the burner pipe (7).
11. Device according to claim 9, wherein the central nozzle head
(6) is surrounded by a ring space that brings about the air or
oxygen feed (5), in known manner, to feed in the fuel gas.
12. Device according to claim 9, wherein the pilot burner (2) is
positioned in the center of a gasification burner (15).
Description
[0001] The invention is directed at a method for ignition and for
operation of burners in the gasification of fuels that contain
carbon, using at least two gasification burners.
[0002] Such a method of procedure, in which multiple dust burners
are ignited by a pilot burner, is shown by DE 10 2005 048 488 A1.
Other methods of procedure for ignition use so-called ignition
lances, for example, as is shown by DE 32 27 155 A1, whereby
passing such movable ignition aids through the firebox walls brings
additional effort with it, and this leads to making such devices
more expensive. Other examples are shown by EP 0 347 002 B1, EP 0
511 479 A1, U.S. Pat. No. 408,628, U.S. Pat. No. 5,273,212, DD 231
962 A, or DD 241 457 A.
[0003] With regard to the state of the art, reference is
furthermore made to DE 196 41 843 A1, DE 195 29 994 C2, DE 100
24003 A1, DE 100 19 198 A1, DE 734 927 A, EP 0 095 103 B1, WO
2008/055829 A1, or AT 286 072 B.
[0004] A disadvantage of the known methods of procedure consists,
among other things, in that the pilot burners or ignition burners
continue to be kept in operation, and in this connection require a
permanent through-flow of gas and oxygen or air, in order to
prevent them from becoming plugged up by slag or the like. In this
connection, it is particularly problematic to keep corresponding
exit openings on the gasifier wall open at high slag flow. As has
just been mentioned, the use of movable ignition lances is
cost-intensive and problematic for other reasons. In this
connection, access channels for gasification must be checked before
introduction of the ignition burner, and usually cleaned, seals
must be replaced, and more of the like, whereby this work must be
carried out in the pressure-free state.
[0005] If this work must be carried out, the gasifier and the
subsequent gas treatment, including H.sub.2S and COS removal, must
first be relaxed and made inert, whereby the fuel gases diluted
with inert gas are usually burned off by way of a flare. After
ignition of the ignition burner, the pressure then has to be raised
slowly, for example 0.5 bar/min, and the inert gas must be
displaced by the gas produced in the gasifier, whereby once again,
the displaced gas, which is mixed with fuel gas, must be burned off
in the flare. This method of procedure is not only time-consuming,
but rather also has a high ignition fuel consumption with
correspondingly high emission values caused by the flare.
[0006] This is where the invention takes its start, whose task
consists in allowing start of the pressure gasification with short
start times at high pressures, without prior inertization of the
gas space, while avoiding continuous fuel gas consumption in the
pilot burner or ignition burner, whereby in the case of stationary
ignition burners, these are also protected against
contamination.
[0007] This task is accomplished, according to the invention, with
a method of procedure of the type indicated initially, in that one
of the gasification burners is configured as a start-up burner, for
the ignition of which at least one pilot burner serves, which is
ignited by way of an electrical ignition device, whereby a
combustible gas mixture composed of a fuel gas and gas that
contains oxygen is ignited by the pilot burner, in the start-up
burner, whereby after ignition of the start-up burner, at least one
further gasification burner is ignited by this burner, and the
start-up burner is operated further as one of the gasification
burners of the fuel that contains carbon, by means of a change in
medium.
[0008] By means of this ignition, which takes place in the manner
of a cascade, a number of advantages are achieved, which
particularly make it possible for ignition at high pressure to be
possible, and to eliminate a movable or displaceable ignition
device. In this way, the need to clean the access channel of the
displaceable ignition burner before every start and to renew the
seal of the corresponding channel is also eliminated. This method
of procedure, according to the invention, particularly makes it
possible for a plurality of gasification burners to be operated as
start-up burners, with the use of a pilot burner during
start-up.
[0009] A fast pressure increase before ignition of the gasification
burner is possible without inertization of the gas space, and
emissions during flare burn-off during shut-down and start-up are
eliminated, to name only a few advantages.
[0010] Embodiments of the invention are evident from the dependent
claims.
[0011] In this connection, individual pilot burners can be ignited,
thereby making it possible to use the combustible mixture produced
by the corresponding gasification burners and the flame formed from
it to subsequently ignite the gas/oxygen mixture from other
gasification burners. In this connection, the power and stability
of the ignition flames are increased. These can then ignite further
carbon burners, whereby the regulation and monitoring concept of
the start routine is greatly simplified.
[0012] A further embodiment of the method of procedure according to
the invention consists in that the pilot burner, after ignition of
the start-up burner, additionally has a gas mixture applied to it
that contains CO.sub.2 and/or steam and/or oxygen, if applicable
also inert gas, in order to prevent it from clogging, so that the
pilot burner is fully integrated into the gasification system.
[0013] It is also advantageous if the pilot burner is first ignited
at less than 50% of the power of the gasification burner that is
operated as a gas burner, and at an oxygen excess number of 0.8 to
1.2, whereby it can also be provided that to accelerate the
ignition of the mixture that contains oxygen, in the gasifier, the
pilot burner has a fuel excess/oxygen excess number<0.8 applied
to it.
[0014] An aid in ignition of the gasifier consists in monitoring
the ignition flame of the pilot burner, whereby the flame is
monitored in such a manner that the ignition element of the pilot
burner is shut off when the flame is recognized.
[0015] If the flame is monitored using an ionization flame monitor,
the ignition element of the pilot burner can be used as a
corresponding electrode, as the invention also provides.
[0016] According to the invention, an optical flame monitor can be
used, or the change in the electrical resistance of the ignition
element can be used to recognize the flame.
[0017] The task formulated above is accomplished with a device, in
that the pilot burner is equipped with a centric nozzle head, which
is surrounded by a burner pipe, which projects beyond the nozzle
head in the flow direction of the fuel gas, whereby at least one
electrical ignition device is provided within the burner pipe
space, and a reduction in cross-section of the burner pipe is
provided in the flow direction behind it.
[0018] With this embodiment, it is possible to use an electrically
heated ceramic glow element, for example. The reduction in
cross-section in the burner pipe ensures a production of spin in
the nozzle region, so that hot gas is passed back into the
surroundings of the nozzle orifice, and the colder mixture of
freshly supplied gases is ignited, and, in addition, a higher
turbulence level can be set in order to bring about simple
ignition. In this way, the flame can be stabilized by means of the
corresponding constrictions.
[0019] As was already mentioned further above, it is important to
monitor the flame of the pilot burner, whereby according to the
invention, at least one flame monitoring element is assigned to the
burner pipe, for example an optical flame monitoring device with a
fiberglass line to a corresponding electronic component.
[0020] As will be described further below, the burner according to
the invention has ring-shaped channels, whereby gas that contains
oxygen is fed in through the first ring-shaped channel of the
start-up burner, both during the ignition process and during normal
operation, in such a manner that the orifice of the pilot burner is
surrounded by a clean gas. If the pilot burner has a gas mixture
applied to it after ignition, in order to prevent it from becoming
clogged, this has the advantage that the fuel excess can react with
the oxygen from the first ring channel.
[0021] Further characteristics, details, and advantages of the
invention are evident from the following description and using the
drawing. This shows, in
[0022] FIG. 1 a section through a pilot burner according to the
invention, in a simplified representation,
[0023] FIG. 2 a top view of the pilot burner according to the arrow
II in FIG. 1, and in
[0024] FIG. 3 a gasification burner with a centrally integrated
pilot burner.
[0025] The device for ignition and for operation of burners in the
gasification of fuels that contain carbon, designated in general
with 1, is essentially formed by a pilot burner, represented
schematically and in simplified manner in FIG. 1, and designated
with 2, which burner has a fuel gas nozzle 3 to which the
corresponding fuel gas is supplied at 4, whereby the fuel gas
nozzle 3 is equipped with an air feed 5 that surrounds the fuel gas
nozzle 3 concentrically. In the flow direction of an ignition
flame, not shown in the figures, the nozzle head designated with 6
is surrounded by a burner pipe 7.
[0026] As can be seen in FIG. 1, an electrical ignition element,
for example a glow element 9, which is connected with a
corresponding power source by way of an electrical line 10, for
igniting the fuel gas/air mixture, projects into the pipe space 8
formed by the burner pipe 7. In order to produce stable flames and
optimal burner behavior, a constriction, indicated in general with
11, projects into the space formed by the burner pipe 7, in the
orientation of the flame that is formed, in order to thereby bring
about swirling or circulation of the gas, as indicated with an oval
circle 12 in FIG. 1, with a broken line.
[0027] The pilot burner 2 is preferably situated in the central
channel of the gasification burner, and is thereby protected from
dirt by means of the gas that flows out through the inner ring
channel. In addition, the central pilot burner channel can be
flushed by means of a gas.
[0028] In addition, as is evident from FIG. 2, an optical flame
monitoring element 13 can also be provided on the burner head 6,
which element is surrounded by a protective pipe 14. In this
connection, the sudden constriction 11 is not shown separately in
FIG. 2, so that the elements 5 and 13 can be shown.
[0029] From FIG. 3, it is evident that the pilot burner 2 can
represent an integral component of a gasification burner, indicated
in general with 15, whereby the individual ring spaces and feed
spaces of the gasification burner are reproduced in simplified
manner here. This gasification burner 15 can be operated as a
start-up burner, as has been described above.
[0030] In FIG. 3, the ring space or ring channel for primary oxygen
is indicated with 16; 17 indicates the ring channel for the fuel,
for example a gas or a dust suspension, 18 designates the ring
channel for the secondary oxygen, and 19 designates the ring
channel for inert or low-oxygen gas, for example N.sub.2, CO.sub.2,
steam, or steam+O.sub.2. Finally, in FIG. 3, 20 also designates the
outer pipe of the gasification burner, 21 designates the orifice of
the gasification burner, and 22 designates the orifice of the pilot
burner.
[0031] Example for an advantageous media change in the pilot burner
and the adjacent channels of the gasification burner.
TABLE-US-00001 Ignition Channel process Normal operation 4 Fuel gas
No gas or a gasification medium or an inter gas 5 Gas that No gas,
if the burner is directed contains downward, for example oxygen
advantageously, a gasification medium that contains either O.sub.2
and/or CO.sub.2 or steam or a fuel gas that was supposed to be
broken down in the gasifier 16 Gas that Gas that contains oxygen
contains oxygen 17 Fuel gas Pneumatically conveyed fuel 18 Gas that
Gas that contains oxygen contains oxygen
There is also the possibility of having inert gas flow through the
ring channels 16 to 19 to flush the channel, in each instance. In
this way, for example, inert gas can flow through the channel 6,
and thus prevent contamination in the region of the orifice of the
pilot burner 22.
[0032] The size of the back-flow region 12 oval/circle can be
influenced by means of the L/D ratio.
[0033] A monitoring element 13 for flame monitoring can be a lens
system that has flushing air applied to it to prevent
contamination, or also for cooling. This system can be surrounded
with a protective pipe (FIG. 2, 14 protective pipe). A monitoring
element can also be implemented by means of a suitable light guide
system.
[0034] The monitoring element can be integrated parallel to the
nozzle channel of the fuel gas line.
[0035] Another implementation possibility exists in such a manner
that this monitoring element is integrated centrally within the
fuel gas feed channel, so that flame monitoring takes place through
the nozzle channel.
[0036] The monitoring element can recognize the flame of the pilot
burner, for one thing, and, in the event that the pilot burner is
shut off, can also be used to recognize a flame of the carbon
burner, operated as a gas burner, by means of using the signal.
[0037] In this connection, the method of effect of the device
according to the invention is the following:
[0038] Fuel gas and the air required for combustion are supplied to
the pilot burner 2 or the central nozzle 3. This gas mixture flows
into the interior of the burner pipe 7, designated as 8, into which
the electrical ignition element, for example a glow element,
designated as 9, projects, whereby the position of such a glow
element is determined in such a manner that optimal ignition of the
fuel/air mixture is guaranteed. This can be a location through
which there is weak flow, for example, at which back-flow of the
fuel gas/oxygen mixture takes place before ignition, or of the hot
waste gas after ignition.
[0039] Not shown is the possibility that multiple glow elements 9
can be provided, which, as already mentioned above, can also be
used to measure the ionization stream.
[0040] The burner pipe 7 can stabilize the flame within the pipe
with a sudden constriction 11, whereby part of the hot waste gases
are deflected by means of the constriction, and the circulation 12
is reinforced. As a result, the fresh, cold mixture of the supplied
gases is reliably heated above the ignition temperature with the
circulating hot waste gases. The flame penetrates from the burner
pipe 7 into the gasification space, and there then ignites a
combustible gas mixture of fuel gas and oxidation media, which flow
out of the ring channels 16 to 19 of the gasification burner during
the ignition phase. After the gasification burners have been
ignited, gasification media such as CO.sub.2, steam, or mixtures
with oxygen can be passed to the combustion space not only by way
of the fuel gas feed line of the pilot burner 4, but also by way of
the air feed line 5, thereby ensuring that no dust deposits or
caking form in the pilot burner.
[0041] Of course, the invention is not restricted to the exemplary
embodiments that are shown. Further embodiments are possible
without departing from the basic idea. For example, alternative
injection of the corresponding media into the pilot burner can be
modified and adapted to the cases of use, in each instance, the
pilot burner can be operated at a fuel gas excess, the combustion
media in the pilot burner can be formed by air or oxygen with
nitrogen or CO.sub.2 or with steam, in order to avoid soot
formation at sub-stoichiometric combustion, for example, but the
air can also be enriched with oxygen, the oxygen feed can be
supplied with and without spin, and the like.
* * * * *