U.S. patent application number 13/821977 was filed with the patent office on 2013-08-29 for method and apparatus for automatic removal of carbon deposits from the oven chambers and flow channels of non-recovery and heat-recovery coke ovens.
This patent application is currently assigned to THYSSENKRUPP UHDE GmbH. The applicant listed for this patent is Ronald Kim. Invention is credited to Ronald Kim.
Application Number | 20130220373 13/821977 |
Document ID | / |
Family ID | 44651616 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130220373 |
Kind Code |
A1 |
Kim; Ronald |
August 29, 2013 |
METHOD AND APPARATUS FOR AUTOMATIC REMOVAL OF CARBON DEPOSITS FROM
THE OVEN CHAMBERS AND FLOW CHANNELS OF NON-RECOVERY AND
HEAT-RECOVERY COKE OVENS
Abstract
A method for the automatic removal of carbon deposits from the
oven chambers and flow channels of non-recovery and heat-recovery
coke ovens, where a coke oven battery, composed typically of a
plurality of adjacently arrayed coke oven chambers, is utilized for
the cyclical coking of coal, and where an air metering device which
operates with superatmospheric pressure is used in order to remove,
by combustion, carbon deposits in the flow cross-sections of the
oven system and thereby to counteract a reduction in oven
performance. An apparatus with which this method can be performed
is also disclosed, this apparatus being integrated into the coke
oven battery and at least one coke oven chamber wall, allowing the
carbon deposits to be removed during operation without a change in
any arrangement.
Inventors: |
Kim; Ronald; (Essen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kim; Ronald |
Essen |
|
DE |
|
|
Assignee: |
THYSSENKRUPP UHDE GmbH
Dortmund
DE
|
Family ID: |
44651616 |
Appl. No.: |
13/821977 |
Filed: |
August 16, 2011 |
PCT Filed: |
August 16, 2011 |
PCT NO: |
PCT/EP2011/004110 |
371 Date: |
May 8, 2013 |
Current U.S.
Class: |
134/18 ;
202/241 |
Current CPC
Class: |
C10B 43/10 20130101;
C10B 15/02 20130101; C10B 43/02 20130101; Y02P 20/129 20151101 |
Class at
Publication: |
134/18 ;
202/241 |
International
Class: |
C10B 43/02 20060101
C10B043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2010 |
DE |
10 2010 044 938.5 |
Claims
1. Method for automatic removal of carbon deposits (11) from oven
chambers (1) and flow channels (10) of "Non-Recovery" and
"Heat-Recovery" coke ovens, wherein a coke oven bank (22) comprised
of several coke oven chambers (1) having two lateral coke oven
chamber walls (9) each and "downcomer" channels (10) arranged
therein is supplied with compressed air (15) via compressed air
main (19), characterized in that a partial stream of compressed air
(15) streaming into the "downcomer" channels (10) and being
lockable is branched off into at least one coke oven chamber (1),
and this partial stream of compressed air (15) is periodically
conducted into at least one "downcomer channel" (10) so that carbon
deposits (11) contained therein can be removed by a compressed air
blow (15) injected into the "downcomer" channel (10).
2. Method according to claim 11, characterized in that the
measuring parameter is a pressure parameter measured at least at
one spot in a coke oven (1).
3. Method according to claim 2, characterized in that the pressure
parameter is a pressure differential measured in the combustion
chambers (6,20) underneath and above the coal and coke cake (4),
and which amounts to .DELTA.p>30 Pa to trigger the compressed
air blow (15).
4. Method according to claim 2, characterized in that the pressure
parameter is a pressure differential measured between the gas space
(6) of the coke oven chamber (1) above the coal or coke cake (4)
and the ambient atmosphere, and which amounts to -70
Pa<.DELTA.p<+40 Pa to trigger the compressed air blow
(15).
5. Method according to any of the preceding claims 1 to 4,
characterized in that the measuring parameter is a temperature
parameter measured at least at one spot in the coke oven (1).
6. Method according to claim 5, characterized in that the
temperature parameter is the temperature measured in the gas space
(6) above the coke cake (4), and which is less than T=1100.degree.
C. to trigger the compressed air blow (15).
7. Method according to any of the preceding claims 1 to 6,
characterized in that the compressed air (15) is air with an
atmospheric composition.
8. Method according to any of the preceding claims 1 to 6,
characterized in that the compressed air (15) is air which is
enriched with oxygen.
9. Method according to any of the preceding claims 1 to 6,
characterized in that the compressed air (15) is replaced with pure
oxygen.
10. Method according to any of the preceding claims 1 to 6,
characterized in that the compressed air (15) is air which is
enriched with nitrogen.
11. Method according to any of the preceding claims 1 to 6,
characterized in that the compressed air (15) is air which is mixed
with the partially or completely burnt waste gas (29) of the coke
oven chamber (1).
12. Method according to any of the preceding claims 1 to 11,
characterized in that the measuring value of at least one pressure
or temperature measuring parameter is recorded, evaluated, and
controlled by a digital computer unit (31) so that this computer
unit (31) depending on the measuring values turns-on at least one
compressed air blow (15) into an ancillary piping (13) and the
associated "downcomer" channels (10).
13. Method according to any of the preceding claims 1 to 12,
characterized in that the measuring value of at least one pressure
or temperature measuring parameter is recorded, evaluated, and
controlled by a digital computer unit (31) so that this computer
unit (31) depending on the measuring values turns-on at least one
compressed air blow (15) into a distribution mains (14) and the
associated "downcomer" channels (10).
14. Method according to any of the preceding claims 1 to 13,
characterized in that the measuring value represents an empirical
determination of a time interval, according to which this partial
stream of compressed air (15) is periodically conducted into at
least one "downcomer channel " (10).
15. Device for automatic removal of carbon deposits (11) from coke
oven chambers (1) and flow channels (10) of "Non-Recovery" and
"Heat-Recovery"--coke ovens, the said device comprised of a
compressed air mains installed (12) installed on the oven top (17)
of a coke oven bank built-up of several coke oven chambers (1) and
connecting the coke oven chambers (1) to each other in transverse
direction, characterized in that the compressed air mains (12) on
the top (17) is comprised of at least one branch which in the
further course of flow terminates in a lockable ancillary piping
(13) which in a "downcomer" channel (10) arranged in a lateral coke
oven wall (9) has a pipe end to emit compressed air (15).
16. Device according to claim 15, characterized in that the
compressed air main (12) on the top (17) of the coke oven bank has
at least one branch which in the further course of flow terminates
in a lockable ancillary piping (13) which extends in longitudinal
oven direction from the pusher side to the coke side of the oven
(1), and from which in the further course of flow at least another
distribution main (14) branches off which terminates in a pipe end
(19) arranged in a "downcomer" channel (10) and which is suitable
to emit compressed air (15).
17. Device according to any of the preceding claim 15 or 16,
characterized in that a pipe end (19) which is suitable to emit
compressed air (12) terminates in each "downcomer" channel (10) of
each coke oven chamber (1) of a coke oven chamber bank.
18. Device according to any of the preceding claims 15 to 17,
characterized in that at least one pipe end (19) is comprised of a
built-on nozzle jet attachment which is suitable to eject a
compressed air blow (15).
19. Device according to any of the preceding claims 15 to 18,
characterized in that at least one pipe end (19) is horizontally
angled.
20. Device according to any of the preceding claims 15 to 19,
characterized in that the pipe end is made from a heat-resistant
iron material.
21. Device according to any of the preceding claims 15 to 19,
characterized in that the pipe end is made from a ceramic silica
material.
22. Device according to any of the preceding claims 15 to 19,
characterized in that the pipe end is made from a corundum
material.
23. Device according to any of the preceding claims 15 to 22,
characterized in that the ancilllary piping (13) has an automatable
valve cock element (18c) serving as shutoff device (18) to control
the compressed air flow (15).
24. Device according to any of the preceding claims 15 to 22,
characterized in that the ancilllary piping (13) has an automatable
slide gate element (18a) serving as shutoff device (18) to control
the compressed air flow (15).
25. Device according to any of the preceding claims 15 to 22,
characterized in that at least one pipe end (19) with or without a
built-on nozzle jet attachment has an automatable valve cock
element (18c) serving as shutoff device (18) to control the
compressed air flow.
26. Device according to any of the preceding claims 15 to 22,
characterized in that at least one pipe end (19) with or without a
built-on nozzle jet attachment has an automatable slide gate
element (18a) serving as shutoff device (18) to control the
compressed air flow.
27. Device according to any of the preceding claims 15 to 26,
characterized in that the shutoff device (18) to control the
compressed air flow (15) is hydraulically actuated.
28. Device according to any of the preceding claims 15 to 26,
characterized in that the shutoff device (18) to control the
compressed air flow (15) is electrically actuated.
29. Device according to any of the preceding claims 15 to 26,
characterized in that the shutoff device (18) to control the
compressed air flow (15) is pneumatically actuated.
30. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 24 pressure measuring probes (32a) for
pressure measurement are guided through the inspection opening
ports (16) into the "downcomer" channels (10) of the coke oven
chamber (1) to be liberated from carbon deposits (11).
31. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 3 pressure measuring probes (32a) for
pressure measurement are guided through the oven top (17) of the
coke oven chamber (1) to be liberated from carbon deposits
(11).
32. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 2 pressure measuring probes (32a) for
pressure measurement are guided through the coke oven chamber doors
(2) of the coke oven chamber (1) to be liberated from carbon
deposits (11).
33. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 4 pressure measuring probes (32a) for
pressure measurement are guided through the lateral front walls
(28) of the oven chamber (1) which are located above the coke oven
chamber door (2) and cover the primary heating space (6).
34. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 8 pressure measuring probes (32a) for
pressure measurement are guided through the lateral front walls (9)
of the oven chamber (1), which are located underneath the coke oven
chamber door (2) and cover the secondary heating space (20) or in
the secondary air sole (26).
35. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 2 pressure measuring probes (32a) for
pressure measurement are arranged in the connecting channels (20a)
between the secondary heating space (20) underneath the coal cake
(4) and the waste gas collecting duct (26) of the coke oven
bank.
36. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 2 pressure measuring probes (32a) for
pressure measurement are arranged in the waste gas collecting duct
(26) which extends transversely to the coke oven bank on the oven
top (17).
37. Device according to any of the preceding claims 15 to 29,
characterized in that 1 to 2 pressure measuring probes (32a) for
pressure measurement are arranged in the waste gas collecting duct
(26) which extends transversely to the coke oven bank underneath
the coke oven chamber doors (2).
38. Device according to any of the preceding claims 15 to 37,
characterized in that at least one thermocouple (32b) is guided
into the gas space (6) above the coke cake (1) through the coke
oven chamber doors (2) of the coke oven chamber (1) to be liberated
from carbon deposits (11).
39. Device according to any of the preceding claims 15 to 37,
characterized in that at least one thermocouple (32b) is guided
through the inspection opening ports (16) into the "downcomer"
channels (10) of the coke oven chamber (1) to be liberated from
carbon deposits (11).
40. Device according to any of the preceding claims 15 to 37,
characterized in that at least one thermocouple (32b) is guided at
the vault crest through the oven top (17) the coke oven chamber (1)
to be liberated from carbon deposits (11).
41. Device according to any of the preceding claims 15 to 40,
characterized in that the said device has a digital computer unit
(31) which records, evaluates and controls the control values of at
least one pressure sensor (32a) or one thermocouple (32b) so that
by means of this control unit (31), depending on the measuring
values, at least one compressed air blow (15) in the ancillary
piping (13) and in at least one downcomer channel (10) is turned
on.
Description
[0001] The invention relates to a method for automatic removal of
carbon deposits from flow channels in "Non-Recovery" and
"Heat-Recovery" coke ovens, there being utilized one coke oven bank
typically comprised of several coke oven chambers arranged side by
side for cyclical carbonization of coal, and there being used an
air dosage facility operating at positive pressure in order to
remove carbon deposits accumulating in flow cross-sections of the
oven system by combustion and thereby counteracting a reduction of
the oven performance rate. The invention also relates to a device
by means of which this method can be implemented, wherein this
device is integrated into the coke oven bank and at least into one
coke oven chamber, so that carbon deposits can be removed during
operation without modifying any arrangement.
[0002] Carbonization of coal to obtain coke is often accomplished
in coke oven chambers of the so-called "Non-Recovery" or "Heat
Recovery" type which are distinguished from conventional coke oven
chambers in that the coke oven gas evolving during coal
carbonization is not captured and recovered but utilized for
combustion and heating. On coal carbonization in this oven type,
the gas evolving during coal carbonization streams into a gas space
located above the coke cake where partial combustion of the coke
oven gas occurs with a sub-stoichiometric quantity of air. As a
result hereof, the coal or coke cake is heated from above. The gas
space above the coke cake is also called primary heating space.
[0003] Partly burnt coking gas from the primary heating space is
then passed via so-called "downcomer" channels into flue gas
channels located under the coke oven chamber bottom floor and
provided for complete combustion of partially burnt coke oven gas.
These are supplied with secondary combustion air through secondary
air soles connected to the atmosphere outside. The gas space under
the coke cake is also called secondary heating space. In the
majority of layouts, the vertically arranged downcomer channels
pointing downwards in the direction of flow are located in
non-frontal side walls of the coke oven chambers whereby partially
burnt coke oven gas streams into the flue gas channels.
[0004] An embodiment for coke oven chambers comprised of downcomer
channels in side walls is described in WO 2009077082 A2. This
invention relates to a device for feeding and controlling of
secondary air from secondary air ducts into flue gas channels of
horizontal coke oven chambers. The flue gas channels are located
underneath the coke oven chamber floor on which coal carbonization
is realized. Controlling elements which can precisely control the
air flow into the flue gas channels are mounted in the connecting
channels between the flue gas channels and secondary air ducts
which serve for the supply of secondary air. The coke oven chamber
is comprised of so-called "downcomer" channels for discharge of
partially burnt gases from the carbonization process which are
integrated in the lateral coke oven chamber wall, these "downcomer"
channels connecting the coke oven chamber interior with the flue
gas channels.
[0005] In most layouts, the number of downcomer channels in one
coke oven chamber wall amounts up to 12, so a total of 24 downcomer
channels can be provided per oven. The downcomer channels are
downwards directed and in the majority of layouts, they are
arranged in the walls of coke oven chambers because two walls each
laterally enclose one coke oven chamber. In the upper section of a
downcomer channel, the flow cross-section can be altered by means
of an adjusting element, thus it is possible to adjust the effluent
gas volume stream from a channel in longitudinal oven
direction.
[0006] Partially burnt coke oven gas is composed of gas components,
i.e. hydrogen, carbon monoxide, water, methane as well as, though
in lesser portions, ethane, ethene, propane, propene and
higher-grade hydrocarbons, for example benzene, toluene, xylene.
Thus it contains volatile compounds which may condensate or
pyrolyse in the downcomer channels and which lead to non-desired
carbon deposits. Carbon deposits thus formed are composed of
tar-laden, soot-forming compounds, and more particularly of
graphite, and in the course of operating time these deposits may
build-up in substantial quantities. In particular, these deposits
accumulate in the downcomer channels in case temperatures in these
channels are too low and if no further combustion air is admitted.
Thereby, these deposits constrain or block the flow cross-sections
of the downcomer channels.
[0007] U.S. Pat. No. 6,187,148 B1 describes a valve for a
Non-Recovery coke oven through which the gas pressure in the
interior of a coke oven chamber can be better controlled and
whereby a supply of air into the downcomer channels is feasible.
The valve has a rotating plug with a beveled end which
progressively connects or disconnects the interior cavity of a coke
oven chamber with the downcomer channel in order to control and
regulate the gas pressure in the oven interior. By controlling the
gas pressure, the volume of combustion air can be controlled as a
function of the temperature gradients admitted into the oven. The
combustion of a majority of the coal gas in the secondary heating
spaces below the coke oven chamber, depending on the valve aperture
degree, creates a thermal gradient through the coke oven chamber
floor whereby coke quality is substantially improved. This
publication does not describe the formation of deposits due to the
pyrolysis of coke oven gas.
[0008] Owing to a combination of a low partial pressure of oxygen
and a low temperature, these cracked hydrocarbon compounds
preferably deposit at the entrance cross-sections or within the
downcomer channels directed downwardly into the lower oven, for
example in form of elementary carbon, graphite, tar, soot or
similar compounds. Carbon-laden deposits pose a noticeable factor
of interference for the operation of coke oven chambers. For
example, such deposits constrain gas-conducting facilities so that
the flow of gas for heating is slowed down or even prevented.
[0009] This problem has hitherto been solved virtually by feeding
compressed air periodically into the downcomer channels, depending
on the visual appearance of oven emissions and depending on the
estimated oven performance rate, so that carbon deposits are
removed from the cross-section by way of a compressed-air pulse.
For this purpose, the lockable downcomer channel inspection ports
arranged on the oven top are utilized to ensure access to the
channels located underneath when being in open status. To clean
these channels, operators manually blow compressed-air through a
compressed-air lance into the inspection port for a certain period
of time. Through the introduced compressed-air, carbon deposits in
the further course of flow are burnt with the free OH radicals
contained in air. The supply with compressed-air is ensured, for
example, by way of a mobile compressor.
[0010] Though this manual procedure removes carbon deposits, it is
liable to failures, because in a status when the oven doors are
closed the entrance cross-section of the downcomer channels cannot
be visually inspected during operation from the oven top. The
concurrently reduced process velocity in turn frequently entails
delays in the operational sequencing.
[0011] A permanent supply of air into the downcomer channels of the
downwardly directed lateral chamber walls already leads to a
complete combustion of the partially burnt crude gases and on
account of the reduced heating performance associated therewith it
is non-desired in flue gas channels further downstream underneath
the oven chamber. As the downcomer channels are constrained or
blocked, the negative pressure in the oven chamber above the coal
is reduced or it may even happen that a positive pressure is
developed. With a reduction of the negative pressure, the aspirated
portion of air is reduced, and with a positive pressure, the
required primary combustion air can no longer stream into the oven
chamber. In this case, released crude gas escapes from primary air
opening ports in the oven top and oven door, thereby causing a
substantial ecological burden. Therefore, possibilities are
searched for to either avoid or periodically remove such deposits.
However, a visual monitoring is non-desired for practical and
economic considerations.
[0012] Carbonization of coal according to the "Non-Recovery" or
"Heat Recovery"--principle follows a distinct coking cycle in the
course of which distinct values of temperature and pressure prevail
at the relevant spots of a coke oven chamber. During coal
carbonization, a certain amount of coal is charged at ambient
temperature into the oven chamber to be charged and operated
sub-stoichiometrically above the oven sole. Owing to this
circumstance, a temperature drop which can be documented by
thermocouples usually arranged in the oven chamber vault area
initially occurs in this oven chamber.
[0013] In normal operation, after the charging procedure within a
time interval of .tau./.tau..sub.End=0 to 0.15, the temperature
drop in an oven chamber is characterized in that a temperature
minimum of the oven chamber temperature ranges between 800.degree.
C. and 1150.degree. C., depending on the oven type. The ratio
.tau./.tau..sub.End corresponds to the standardized operating time
of the oven. Starting from an initial temperature level of approx.
1000.degree. C. to 1450.degree. C. at the moment of charging the
oven (.tau./.tau..sub.End=0), the temperature in the oven chamber,
depending on the oven type, falls shortly by approx. 200.degree. C.
to 350.degree. C. During the subsequent time interval
.tau./.tau..sub.End=0.15 to 1.0, the oven chamber temperature again
comes close to the initital temperature level.
[0014] DE 102006004669 A1 teaches a coking oven in flat
construction style, a so-called non-recovery or heat-recovery
coking oven which is comprised at least of a measuring device to
measure the concentration of gas constituents of a coke oven
chamber, coke oven sole and/or waste gas flue, and in which the
optimal feed of primary and/or secondary air is determined and
controlled via a process computer on the basis of these data. The
invention also covers a coal carbonization process utilizing such a
coking oven. The invention teaches the application of measuring
parameters for automated control of the feed of combustion air, but
it does not describe the removal of carbonaceous deposits with the
peculiarities of this task.
[0015] The pressure in a coke oven chamber also varies in the
course of the coke making process. "Non-recovery and heat-recovery"
coke ovens operate in negative pressure mode, whereof an
emission-friendly appearance is derived for this oven type. The
level of the negative pressure in the chambers is usually adjusted
and set through a suction blower or by exploiting the natural draft
of a chimney so as to make a sufficient stream of air volume
available for the combustion of the maximal crude gas volume stream
escaping during the initial phase of coal carbonization in order to
avoid flame-off losses and emissions through primary air opening
ports and oven doors. Negative pressures in the oven chamber above
the coal cake may range between -10 Pa and -100 Pa.
[0016] Thus there are indicators on the basis of which a periodical
removal of carbonaceous coverings can be effected. Now, therefore,
it is the object to perform a removal of carbonaceous coverings at
suitable spots inside a coke oven chamber based on measured values
for pressure and temperature. The removal of carbonaceous coverings
is to be performed in the simplest possible manner in order to be
able to perform a removal of these coverings without shutting down
the coke oven chamber or even in running operation.
[0017] The present invention solves this task by providing for a
method according to which compressed air is periodically conducted
into the downcomer channels depending on at least one measuring
parameter so that carbon deposits accumulating therein are
removable by an injection of compressed air blown into the
downcomer channel. Removal of coverings is accomplished by way of
combustion in such a manner that the carbonaceous coverings react
with the free OH radicals as well as with the oxygen of the gas
introduced and that an additional suction and cleaning effect is
achieved by the inlet pulse of compressed air. Injection of
compressed air is performed with advantage through the inspection
ports of the downcomer channels because these are easily accessible
and because a retrofit is readily possible.
[0018] Control of air injection, for example, can be accomplished
via a measurement of pressure at any spots of the coke oven
chamber. However, the control of air injection, for example, can
also be accomplished via a measurement of temperature at any spots
of the coke oven chamber. The introduced compressed air contains
the oxygen required to burn-off the coverings. A gas enriched with
oxygen may also be utilized to implement the present invention.
[0019] Control of air injection, for example, can also be
accomplished via an operationally optimized timer, whereby
compressed air is injected within fixed time intervals for an
optional period of time into the downcomer channel. The time
intervals are then stipulated empirically, for example by
evaluation of visual check-ups of the downcomer channels.
[0020] The present invention makes it possible to remove
carbonaceous coverings during operation without requiring an
interruption of operation or dismantling of a coke oven chamber.
Air or oxygen-laden gas is conducted with the desired approach
through measuring signals or upon expiry of a determined time
interval into the downcomer channels so that a temporal
introduction of oxygen-laden gas is effected. A partial
cooling-down of the downcomer channels involved by an excessive or
uncontrolled supply of oxygen-laden gas and entailing possible
damage to a coke oven chamber is thus avoided.
[0021] Claim is laid in particular to a method for automatic
removal of carbon deposits from coke oven chambers and flow
channels in "Non-Recovery" and "Heat Recovery" coke ovens, wherein
[0022] a coke oven bank comprised of several coke oven chambers
each comprised of two lateral coke oven chamber walls and downcomer
channels arranged therein is supplied with compressed air through a
compressed air mains, and which is characterized in that [0023] a
partial stream of compressed air is branched off into at least one
coke oven chamber and streams into the downcomer channels and can
be shut off, and [0024] this partial stream of compressed air,
depending on at least one measuring parameter, is periodically
conducted into at least one downcomer channel so that carbon
deposits accumulating therein are removable by a blow of compressed
air injected into the downcomer channel.
[0025] This measuring parameter, for example, is a pressure
parameter which is measured at least at one spot in the coke oven.
It is then related to an already known design value or to another
measurable pressure value. As a rule, one or two individual
pressure parameters are thus measured. For example, the pressure
parameter is a pressure differential measured in the combustion
chambers below and above the coal and coke cake, i.e. between the
primary heating space and the flue gas channels underneath the coke
oven chamber and which amount to .DELTA.p>30 Pa to release and
trigger the blow of compressed air injection. The pressure
parameter may be a pressure differential measured between the gas
space of a coke oven chamber, the primary heating space, and the
ambient atmosphere, and which amounts to -70 Pa<.DELTA.p<40
Pa to release and trigger the blow of compressed air injection.
[0026] In case the downcomer channels are blocked due to a clogging
upstream, then the pressure differential between both combustion
chambers, i.e. between the primary heating space and the secondary
heating space, empirically rise to values of .DELTA.P>30. Due to
the clogging, the secondary combustion process in the secondary air
soles lacks the partially burnt coking gas. As a consequence, the
coal charge is solely heated from above, i.e. by the heat from the
primary combustion process This leads to a reduced process velocity
which empirically results in a reduction of the oven performance
rate.
[0027] The measuring parameter may also be a temperature parameter
which is measured at least at one spot in the coke oven. This
temperature parameter, for example, is the temperature measured in
the gas space above the coke cake and which exceeds T=1100.degree.
C. to release and trigger the blow of compressed-air injection.
[0028] The control of air injection, for example, can also be
accomplished via a timer according to fixed time intervals for
certain time periods, without requiring an additional evaluation of
measured values. The partial stream of compressed air is then
periodically conducted with a fixed time interval into at least one
downcomer channel so that carbon deposits accumulating therein are
removable by an injection of compressed air blown into the
downcomer channel. The time intervals are then stipulated
empirically, for example by evaluation of visual check-ups of the
downcomer channels.
[0029] The compressed air is for example a normal, non-dried air
with an atmospheric composition. It is brought through a compressor
to a pressure level that is suitable for introduction or injection
into the inspection ports of the downcomer channels. However, the
compressed air may also be air which is enriched with oxygen. In
another embodiment of the present invention, the compressed air may
also be replaced with pure oxygen. For better execution, the
compressed air may also be enriched with combustion-inert gases.
Hence, the compressed air may also be enriched with nitrogen or
waste gas branched off from the combustion process. The medium may
also be pure oxygen. Finally, the compressed air may be air which
is mixed with the partially or completely burnt waste gas of the
coke oven chamber. The medium is typically supplied at a positive
pressure of 0.1 to 10 bar. The medium may be dried or
non-dried.
[0030] To release and trigger the compressed air blow, the
measuring values of the probes are advantageously picked-up,
evaluated and controlled by a digital computer. To implement the
present invention, it is already sufficient if the measuring value
of at least one pressure or temperature parameter is picked-up,
evaluated and controlled by a digital computer so that this
computer depending on the measuring values turns on at least one
blow of compressed air into an ancillary piping and the associated
downcomer channels. But the computer may also turn on at least one
blow of compressed air injection into a distribution mains and the
associated downcomer channel depending on the measuring values.
[0031] It is also feasible to effect a periodical introduction of
compressed air based upon empirical values. In one embodiment of
the present invention, the measuring value represents an empirical
determination of a time interval according to which this partial
stream of compressed air is periodically conducted into at least
one downcomer channel. As an example, the empirical values can be
determined visually or by preceding measurements.
[0032] A removal of carbonaceous coverings can be performed at each
downcomer channel of all coke oven chambers. But a removal of
carbonaceous coverings can also be performed at individual
downcomer channels of all coke oven chambers, at each downcomer of
one coke oven bank only, or at each individual downcomer of just
one coke oven bank. It is also conceivable to effect the removal of
carbonaceous coverings at further spots of the coke oven chamber,
although the downcomer channels represent the preferred place of
applying the present invention.
[0033] Due to the large geometrical distance of several meters to
the relevant downcomer channels located downstream, a removal of
carbonaceous coverings by means of a prior art controlled elevated
primary volume stream into the coke oven chamber yields no cleaning
effect. For ovens with air supply through the top, this is reasoned
by the fact that the primary air flow streaming through the oven
top initially enters in normal direction into the coke oven
chamber, said air stream being vertically directed downwards and
striking there upon the coal cake surface. On this way further
downwards, the oxygen concentration continuously decreases owing to
combustion processes, and the residual oxygen concentration resting
at the coal cake surface finally is so small that it does not cause
any effects there in terms of combustion and removal of deposits
due to the large distance to the downcomer channels.
[0034] A disproportional increase in primary air volume is not
possible because the process requires sub-stoichiometrical
conditions in the combustion chamber above the charge.
[0035] Claim is also laid to a device by way of which the inventive
method can be implemented. Claim is laid in particular to a device
for automatic removal of carbon deposits from coke oven chambers
and flow channels in "Non-Recovery" and "Heat Recovery" coke ovens,
the said device comprised of [0036] a compressed-air mains
installed on the oven top of a coke oven bank built-up of several
coke oven chambers and connecting the coke oven chambers in
transverse direction, and which is characterized in that [0037] the
compressed-air mains on the top is comprised of at least one branch
which terminates in its further course into a pipe which in one
downcomer channel is comprised of a pipe end to emit compressed
air.
[0038] For example, the compressed air can be furnished by a
compressor. It is then fed into a compressed air main. With
advantage it extends transversely along the coke oven bank. This
can be arranged at the level of the top of the coke oven bank. But
for example, this can also be arranged at the level of service
platforms of the oven sole located laterally at the oven front
sides of the coke oven bank. Moreover, an arrangement of this line
at the level of the ground floor is also conceivable.
[0039] The piping on the top of the coke oven bank is then
comprised of a branch which terminates in its further course into
an ancillary pipe extending in longitudinal oven direction from the
pusher side to the coke side of the oven, and from which at least
another piping branches off in the further course, said piping
terminating into a pipe end which is suitable to emit compressed
air in a downcomer channel.
[0040] To this effect, each coke oven chamber of a coke oven bank
may have a branch at the transversely extending compressed air
mains, said branch then leading in another branch into each
downcomer of the coke oven chamber wall. However, it is also
feasible that only one coke oven chamber has a branch from which
all downcomer channels are supplied with compressed air in further
branches. Furthermore, it is also feasible that each coke oven
chamber has a branch at the transversely extending compressed air
mains, whereby only one downcomer channel is furnished with
compressed air. Finally it is feasible that only one piping on the
top of the coke oven bank has a branch which in its further course
terminates in an ancillary piping extending in longitudinal oven
direction from pusher side to coke side of the oven, and from which
only another distribution mains branches off in the further course
of the flow route which terminates in a pipe end that is suitable
to emit compressed air in a downcomer channel.
[0041] In a simple embodiment, it is also conceivable that a pipe
end suitable to emit compressed air terminates in each downcomer
channel of each coke oven chamber of a coke oven chamber bank.
[0042] In an embodiment of the inventive method, at least one pipe
end has a built-on nozzle jet attachment which is suitable to eject
a compressed air blow. In an advantageous layout, the outlet
openings of the nozzle jet can be so configured that the compressed
air streams at an angle to the vertical line greater than 0.degree.
into the cross-section of the downcomer aperture. In another
embodiment of the inventive method, at least one pipe end is
horizontally angled. As a result hereof, the pipe end which is
suitable to eject a compressed air bow can be pointed to the
entrance opening of the downcomer cross-section. In another
embodiment, the outlet opening of the pipe end can be slotted,
rectangular, annular or circular as well as include a combination
of several outlet shapes of these. The pipe shapes or
configurations for pipe ends as described hereinabove can be
implemented at just one pipe or pipe end, but also at an arbitrary
number of pipes or pipe ends.
[0043] On account of the high temperatures in the downcomer channel
which range between 950 and 1500.degree. C., the pipe end is made
from any material that should be resistant to heat. In exemplary
configurations, the pipe end is made from a heatproof iron
material, a ceramic silica material, or a corundum material.
Preferably this material is selected from the group of
heat-resistant steels or refractory ceramic construction materials.
Out of this group of construction materials, those materials
especially suitable are, for example, materials especially rich in
alumina as well as highly burnt materials based on the raw material
corundum with Al.sub.2O.sub.3-portions ranging between 50-94%,
SiO.sub.2-portions ranging between 1.5-46%,
Cr.sub.2O.sub.3-portions less than 29%, Fe.sub.2O.sub.3-portions
less than 1.6% and ZrO.sub.2-portions less than 32%, because these
materials are characterized by a high temperature of application
over 1500.degree. C.
[0044] To control the stream of compressed air into an ancillary
piping, the ancillary piping is comprised of an automatable valve
cock element to serve as shutoff device to control the stream of
compressed air. The ancillary piping may also be comprised of an
automatable slide gate element to control and regulate the
compressed air flow. The same holds for the pipe ends with our
without a built-on nozzle jet attachment. To control the blow of
injected compressed air, at least one pipe end with or without a
built-on nozzle attachment may be comprised of an automatable valve
cock element to control and regulate the flow of compressed air.
But it is also feasible to choose an automatable slide gate element
to control and regulate the flow of compressed air. Finally, the
control of compressed air can be executed by any arbitrary control
and/or regulating device.
[0045] All the shutoff devices which serve to control and regulate
the compressed air flow can be actuated, for example, electrically,
hydraulically or by compressed air. In an embodiment of the present
invention, the element to control and regulate the compressed air
flow is actuated hydraulically. In another embodiment of the
present invention, the element to control and regulate the
compressed air flow is actuated electrically. In another embodiment
of the present invention, the element to control and regulate the
compressed air flow is actuated pneumatically.
[0046] The arrangement of measured value probes on the oven top,
for example, is taken in such a manner that pressure measuring
probes for pressure measurement are conducted through the
inspection ports into the downcomer channels of the coke oven
chamber to be liberated from carbon deposits. But these can also be
conducted into the primary heating space. For example, 1 to 24
pressure measuring probes for pressure measurement are conducted
through the inspection ports into the downcomer channels of the
coke oven chambers to be liberated from carbon deposits. However,
for pressure measurement, it is also possible to conduct 1 to 3
pressure measuring probes through the oven top of the coke oven
chamber to be liberated from carbon deposits. It is also feasible
to conduct 1 to 2 pressure measuring probes for pressure
measurement laterally through the oven chamber doors of the coke
oven chamber to be liberated from carbon deposits. Finally, it is
also feasible to conduct 1 to 4 pressure measuring probes for
pressure measurement laterally through the front walls of the oven
located above the coke oven chamber door and covering the primary
heating space. In this manner, a comparative signal is available
which takes a temperature or pressure measuring value at one spot
located in the upper section of the coke oven chamber and connected
with the primary heating space.
[0047] The arrangement of the other measuring value probes, for
example, is done in such a manner that 1 to 4 pressure measuring
probes for pressure measurement are conducted through the lateral
front walls of the oven chamber located under the coke oven chamber
door and covering the secondary heating space or into the secondary
air sole. For pressure measurement, it is also feasible to conduct
1 to 8 pressure measuring probes through the lateral front walls of
the oven chamber located under the coke oven chamber door and
covering the secondary heating space or into the secondary air
sole. It is also possible to arrange 1 to 2 pressure measuring
probes for pressure measurement in the connecting channels between
the secondary heating space under the coal cake and the waste gas
collecting duct of the coke oven bank. It is furthermore possible
to arrange 1 to 2 pressure measuring probes for pressure
measurement in the waste gas collecting duct extending transversely
to the coke oven bank on the oven top. It is also possible to
arrange 1 to 2 pressure measuring probes for pressure measurement
in the waste gas collecting duct extending transversely to the coke
oven bank under the coke oven chamber doors. The figures indicated
hereinabove should be understood as exemplary configurations, with
it being possible to arrange individual or several pressure
measuring probes at different positions, too.
[0048] Thus, the pressure measurements can also be taken in the
connecting channels between the secondary heating chamber under the
coal cake and the waste gas collecting duct of the coke oven bank.
In one embodiment, there is an upwardly directed stream in these
channels because the waste gas collecting duct is arranged on the
oven top. In this form, they are therefore also designated as
"uptake" channels and they are also arranged in the lateral coke
oven walls, though between the downcomer channels. By arranging
pressure measuring probes in the gas flow upstream and downstream
of the deposits impeding proper flow through, it is then possible
to determine a pressure differential as a measured value.
[0049] To serve as control signals, it is also feasible to
determine temperature measuring values. With the coke oven chamber
to be liberated from carbon deposits, at least one thermocouple is
conducted in the vault crest of the coke oven chamber to be
liberated from carbon deposits through the oven top or through the
lateral oven doors above the coke cake. Furthermore, at least one
thermocouple can be conducted into the gas space above the coke
cake through the coke oven chamber doors of the coke oven chamber
to be liberated from carbon deposits. It is also possible to
conduct at least one thermocouple through the inspection ports into
the downcomer channels of the coke oven chamber to be liberated
from carbon deposits. Since no temperature differential versus
another measuring value is needed to take-up the temperature
measuring values, the installation of temperature measuring probes
at just one of these positions is feasible. As a matter of fact,
however, several temperature measuring probes may be provided for.
At other positions, too, which are eligible for this purpose, an
installation may be provided for. For example, this can also be
effected at the coke oven chamber wall, even though this approach
is less advantageous. A combined measurement and evaluation of
temperature and pressure measuring signals is also conceivable.
[0050] The control signal can also be given according to a fixed
time interval without measuring data acquisition. Thus, above all
during the initial phase of coal carbonization which is
characterized by particularly high rates of carbon deposits due to
sub-stoichiometric conditions prevailing in the upper oven chamber,
it is advantageous to inject compressed air within shorter time
intervals, e.g. 10 hrs, 24 hrs, and 36 hrs after the charging
procedure, into the downcomers, thereby counteracting a process
retarding in a preventive approach.
[0051] In an advantageous embodiment of the present invention, The
coke oven bank in which at least one coke oven chamber is to be
liberated from carbonaceous coverings is equipped with a digital
computer unit which acquires and evaluates the control values from
at least one pressure sensor or one thermocouple, and which
controls the compressed air unit so that at least one blow of
injected compressed air is turned-on by means of this control unit
depending on the measuring values. In one embodiment, only the
control element per oven wall is actuated that isolates the
ancillary pipe extending from pusher side to coke side from the
main delivery pipe. In this case, the shutoff elements in the
ancillary pipe are in open position and are automatically supplied
with compressed air as soon as the evaluation unit transmits the
signal for opening. In this case, the air volume per downcomer
channel can be adjusted and set manually by means of the valve cock
position or by way of a calibrating element.
[0052] In another embodiment of the present invention, at least one
distribution main which branches off from the ancillary piping or
one pipe end with or without built-on nozzle jet attachment is
comprised of an automatable valve cock element to control and
regulate the compressed air blow. In another embodiment of the
present invention, at least one distribution main which branches
off from the ancillary piping or one pipe end with or without
built-on nozzle jet attachment is comprised of an automatable slide
gate element to control and regulate the compressed air blow.
[0053] The present invention bears the advantage in that
carbonaceous coverings and deposits forming in coke oven chambers
of the "heat recovery" or "non-recovery" type during operation by
pyrolysis of carbonaceous coking gases can be removed without any
further operational interruption in a non-mechanical manner. A
trouble-free operation of the coke oven chambers is thus feasible.
An excessive supply of air and a resultant cooling-off of the
downcomer channels are avoided because the feed is controlled by
measuring values.
[0054] The invention is elucidated in greater detail by way of four
drawings, with the inventive method not being confined to these
embodiments.
[0055] FIG. 1 shows a coke oven chamber with laterally arranged
downcomer channels which can be seen in a frontal view obliquely
laterally from the top.
[0056] FIG. 2 shows a coke oven bank with an arrangement of two
coke oven chambers which can be seen in a frontal view obliquely
laterally from the top.
[0057] FIG. 3 shows a coke oven chamber in a lateral view, which is
comprised of a waste gas collecting duct underneath the coke oven
chamber doors.
[0058] FIG. 4 shows a coke oven chamber in a lateral view which is
comprised of a waste gas collecting duct on the top of the coke
oven chamber.
[0059] FIG. 1 shows a coke oven chamber (1) on which the coke oven
chamber doors (2) have been removed so that the coke oven chamber
opening (3) can be seen. To be seen in the coke oven chamber (1) is
the coal cake (4) which is carbonized and which therefore develops
coking gas (5). The coking gas (5) streams into the primary heating
space (6) where it is mixed with a sub-stoichiometric volume of air
and partially burnt. The partially burnt coking gas (7) streams
through lateral openings (8) in the coke oven chamber wall (9) into
the downcomer channels (10) where carbonaceous deposits (11) are
formed due to the temperature level and the pyrolysis taking place
under sub-stoichiometric conditions. From a compressed air main
(12) extending transversely to the coke oven chamber (1), an
ancillary piping (13) branches-off which extends longitudinally to
the coke oven chamber (1). From this ancillary piping, in turn,
pipes (14) branch off which feed the individual downcomer channels
(10) with compressed air (15). These pipes (14) lead through the
inspection opening ports (16) of the downcomer channels (10) in the
top (17) of the coke oven chamber (1). The feed of compressed air
(15) is controlled and regulated by a shutoff element (18) which in
this case is a slide gate (18a). The slide gate is driven by an
electrical control unit (18b) which is linked to a computer unit.
Upon opening the slide gate (18a), air (15) or an oxygen-laden gas
streams through the pipe end (19) into the downcomer channels (10).
The compressed air mains (12) and the ancillary piping (13) are
also isolated from each other by means of a controllable shutoff
valve (18c) and a control unit (18d). The pipe end (19) may be
arranged at any arbitrary level in the downcomer channel (10), but
is preferably so arranged that the air (15) streams onto the spots
(11) where empirically the majority of deposits accumulate. By
means of a temporal and dosed feed of air (15), the carbonaceous
deposits (11) in the downcomer channel (10) are burnt. Partly burnt
coking gas is then passed into the secondary heating spaces (20)
where it is completely burnt by the feed of further secondary air
(21).
[0060] FIG. 2 shows an arrangement of two coke oven chambers (1) in
a coke oven bank (22), above which a central compressed air main
(12) extending transversely to the coke oven chambers (1) is
arranged. From this compressed air main (12), an ancillary piping
(13) branches-off which extends longitudinally to the coke oven
chambers (1). From this ancillary piping, another distribution
mains (14) branch off which feed the individual pipes (14) with
compressed air (15). The distribution mains (14) are comprised of
pipe ends (19), which terminate in the downcomer channels (10),
where the oxygen-laden compressed air (15) leads to a combustion of
carbonaceous coverings and deposits (11). Two of these pipe ends
(19) are horizontally angled-off (19a). The distribution mains (14)
are shut-off by shutoff elements (18), thus making it possible to
control the feed of air into these distribution mains (14). In the
primary heating room (6), the coking gases (5) streaming out from
the coke cake (4) are burnt with a sub-stoichiometric volume of
air, i.e. primary air (23). The combustion air (23) needed for this
purpose is supplied through primary air opening ports (24) in the
coke oven chamber top (25). The downcomer channels (10) take-up the
partially burnt coking gas (7) from the primary heating space (6)
and lead it into the secondary heating spaces (20) which are fed
with air (21) via the secondary air soles (26). Waste gas from the
secondary heating space (20) is conducted into the central waste
gas duct (27).
[0061] FIG. 3 shows a coke oven chamber (1) in a lateral view. To
be seen here are the frontal coke oven chamber doors (2), which are
illustrated in an embodiment in which the coke oven chamber doors
(2) are perfectly fitted into the coke oven chamber walls (28)
located thereabove. From the coal or coke cake (4) the coking gas
(5) streams into the primary heating space (6), from where it is
conducted via opening ports (8) into the downcomer channels (10).
From there it streams into the secondary heating spaces (20), where
it is burnt through opening ports (20a, 20b) with secondary air
coming from the secondary air soles (26). The completely burnt
coking gas (29) is passed through a collecting duct (30) into a
central waste gas main (27) where the waste gas (29) is collected
and utilized in "Heat-Recovery" ovens for recovery of heat. The
downcomer channels (10) may get clogged with carbonaceous coverings
(11). Therefore, they are fed via a central compressed air main
(12) and an ancillary piping (13) with compressed air which is
distributed via distribution mains (14) with pipe ends (19) into
the downcomer channels (10). Both the distribution main (14) and
the pipe ends (19) can be shut-off via valves (18c, 18). The valves
(18) in turn are linked to a digital computer unit (31) which is
controlled through control signals from sensors (32). The sensors
(32) are located in the primary heating space (6) of the coke oven
chamber (1), where a pressure measuring sensor (32a) and a
thermocouple (32b) are arranged, and in the secondary heating space
(20) under the coke oven chamber (1), where also one pressure
sensor (32a) and one thermocouple (32b) element each are arranged,
and in the central waste gas main (27), where one pressure sensor
(32a) each is arranged in the waste gas collecting duct (30) and in
the central waste gas main (27). The measuring values of the
sensors are picked-up by the digital computer unit (31) which will
then activate the valves (18) of the compressed air mains leading
into the downcomer channels (10). By supplying compressed air, the
carbonaceous coverings (11) in the downcomer channels (10) are
removed. For comparative purposes, two downcomer channels with
carbonaceous coverings (11) are shown in the sketch.
[0062] FIG. 4 shows the same coke oven chamber (1) in a lateral
view, but with a waste gas collecting duct (27) on the top (25) of
the coke oven chamber. On the top (25) it also has a central
compressed air mains (12), from where an ancillary piping (13)
branches off and from where the individual distribution mains (14)
with the pipe ends (19) branch off with the distribution main (14)
into the downcomer channels (10). In the central waste gas main
(27), which is installed here on the top (17) of the coke oven
chamber (1), a pressure sensor (32a) is arranged. In the secondary
heating space, there are two pressure measuring sensors (32a), and
in the primary heating space, there are one pressure measuring
sensor (32a) and one temperature measuring sensor (32b) each. Here,
too, one can see carbonaceous coverings (11) at two downcomer
channels (10) which are removed by the feed of compressed air
(12).
LIST OF REFERENCE NUMERALS
[0063] 1 Coke oven chamber 2 Frontal coke oven chamber doors 3 Coke
oven chamber opening 4 Coke or coal cake
5 Coking gas
[0064] 6 Primary heating space 7 Partially burnt coking gas 8
Openings of downcomer channels 9 Coke oven chamber wall 10
"Downcomer" channels 11 Carbonaceous deposits 12 Central compressed
air mains 13 Ancillary piping 14 Piping as distribution main
15 Compressed air
[0065] 16 Inspection opening ports 17 Top of coke oven chamber 18
Shutoff device 18a Slide gate 18b Electrical control device 18c
Valve cock 18d Electrical control device 19 Pipe end of compressed
air mains 19a Horizontally angled pipe end 20 Secondary heating
spaces
21 Secondary air
[0066] 22 Coke oven bank
23 Primary air
[0067] 24 Primary air opening ports 25 Top of coke oven chamber 26
Secondary air soles 27 Central waste gas main 28 Coke oven chamber
walls
29 Waste gas
[0068] 30 Waste gas collecting duct 31 Digital computer unit 32
Measuring sensor 32a Pressure measuring sensor 32b Temperature
measuring sensor
* * * * *