Note: Descriptions are shown in the official language in which they were submitted.
r
COKE OVELV REPAIR
Technical Field
The present invention relaters generally to the
repair of coke ovens, and more spE=cifically to a
method of repairing a heating wal:L which extends
between adjacent coking chambers in a coke oven
battery, a repair module which is utilized in the
repair, and to the novel heating wall which has been
repaired in accordance with the method of this
invention.
Background of the Invention
Coke is produced by heating pulverized coal in
an air-free environment for a period of time.
Typically, coke is produced in a coke oven battery
which includes a plurality of side-by-side coking
chambers which are separated from each other by
heating walls. The side of the coke oven battery
where the coke is discharged is called the coke
side, and the other side is called the pusher side,
the heating walls and the coking chambers extending
from one side to the other. In a typical
installation the battery may include 40 to 100 or
more side-by-side coking chambers, each chamber
being from 3 to 6 meters high, typically 14 meters
long, and approximately 1/2 meter wide. There is a
slight taper to the width of each chamber so that
coal which has been coked within the chamber may be
pushed out of the chamber, the widith of a chamber at
the pusher side being 3 inches less than the width
at the coke side. Each heating waT.l is typically
built up from a number of horizontally extending
courses of silica bricks, the bricl~;s being assembled
about vertically extending flues within the heating
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walls, which flues cycle between heating and
drafting conditions. There may be eight bricks in
each course for each flue. Thus, in a heating wall
having twenty courses and twenty-eight flues there
may be over 4,400 silica bricks, each brick being
location specific.
The coking chamber is normally maintained at a
temperature of from 2100 to 2500 degrees Fahrenheit.
The coal to be coked is placed (or charged) within
the coking chamber through charging holes at the top
of each coking chamber. During charging and the
following coking period, which may be 24 hours long,
coke oven doors close off the ends of the coking
chamber. While the coking process takes place,
gases are driven from the coal, which gases include
steam, ammonia, sulfur dioxide, NOx, and
hydrocarbons such as methane. These gases are
typically collected for processing into various
chemicals. The gases driven from the coal initially
pass through standpipes which extend from the roof
of the coke oven battery, the gases then being
received by a collecting main. Typically there is a
single standpipe for each coking chamber. The gases
which are driven from the coal during coking cause
the coking chamber's standpipes and the collecting
main to be at a pressure above atmospheric.
At the completion of a coking cycle, the coke
oven doors are removed from both ends of the coking
chamber and the coked coal is pushed from the coking
chamber by a pusher which is forced entirely through
the coking chamber, the coke passing over a coke
guide into a quenching car. When i:he doors are
opened, the pressure within the coking chamber will
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be immediately released and condensed gases or
liquor from the collecting main may reverse flow
through the standpipe onto the silica bricks causing
their surface to spa n . In addition, the cold air
which rushes in after the completion of the coking
operation may also adversely affect the surface of
the silica brick as it has poor resistance to
thermal shock. In any event, after a number of
cycles it is found that the surfaces of the silica
bricks, particularly at the end of t'ne heating wall
adjacent the standpipes, become damaged.
In the past, these heating walls were typically
initially repaired by placing a silica cement over
the vertical surfaces of the heating walls where
damaged. However, it is eventually necessary to
entirely rebuild the damaged end of the heating
walls. As each heating wall contains a large number
of location specific bricks, it becomes a very
time-consuming and expensive project to rebuild a
heating wall. Typically, a crew of five men takes
two to three weeks to rebuild the end of single
heating wall.
Objects and Summary of the Invention
It is the principal object of the present
invention to provide an improved method for
repairing the damaged end of a heating wall of a
coking oven, which improved method includes the
utilization of a novel cast refractory module which
may be utilized to replace existing silica bricks
within a coke oven heating wall.
More specifically, it is an object of the
present invention to provide a cast repair module
for use in the repair of heating walls between
~~~?~
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coking chambers wherein the repaix- module is a
unitary structure formed from a castable refractory
material having high dimensional :stability, the
structure being of a generally boy;-like construction
having vertically extending flues therein, one end
of the structure being adapted to conform to the
shape of the previous end of the heating wall and
the other end being adapted to int:erfit with
existing brickwork.
It is a further object of the present invention
to provide a novel method of repairing a cake oven
heating wall, which novel method incorporates the
utilization of novel cast refractory modules having
high dimensional stability.
The above objects and additional objects and
advantages of this invention will be apparent to
those having ordinary skill in the art after a
consideration of the following detailed description
taken in conjunction with the accompanying drawings
in which a preferred form of this invention is
illustrated.
Brief Description of the Drawinqs
FIG. 1 is a perspective view of the coke side
of a coke oven battery.
FIG. 2 is a partial sectional view taken
generally along the line 2-2 in FIG. 1.
FIG. 3 is vertical section taken generally
along the line 3-3 in FIG. 1 illustrating two
side-by-side coking chambers, heating walls to
either side of the chambers, the intermediate
heating wall having been removed for purposes of
repair.
FIG. 4 is a section taken generally along the
line 4-4 in FIG. 3.
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FIG. 5 is a section taken generally along the
line 5-5 in FIG. 3.
FIG. 6 is a view taken generally along the line
6-6 in FIG. 3.
FIG. 7 is perspective view illustrating one end
of a partially rebuilt heating wall.
FIG. 8 is a section taken generally along the
line 8-8 in FIG. 7.
FIG. 9 is a section taken generally along the
line 9-9 in FIG. 7.
FIG. 10 is a section taken generally along the
line 10-10 in FIG. 7.
FIG. 11 is a top view of one of the repair
modules illustrated in FIG. 7.
FIG. 12 is a view to similar to FIG. 11 but
showing a top repair module.
FIG. 13 is a section taken generally along the
line 13-13 in FIG. 12.
FIG. 14 illustrates a single course of prior
art silica bricks used to form a portion of a
heating wall, which silica bricks are being replaced
by a cast module of this invention.
Detailed Descri tion
Referring first to FIG. 1, a portion of a coke
oven battery is illustrated, the coke oven battery
being indicated generally at 10. 'rhe form of coke
oven battery illustrated is sometimes referred to as
a by-products coke oven since the volatiles driven
off during the coking process are collected in a
collector main 12 for subsequent processing into
some of the thousands of different by-products which
can be derived from the coke oven volatiles. The
coke oven battery includes a plurality of coking
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chambers 14 (FIGS. 2-4), each of t:he coking chambers
extending the full length of the coke oven battery
from the pusher side 16 (FIG. 4) t:o the coke side
18. Each coking chamber 14 may be' 45 feet in
length, and also may have a height: of 3 to 6 meters,
5 meters being typical. The coking chambers are
built with a slight taper, the width at the pusher
side being for example 16 inches a.nd the width at
the coke side being 19 inches. During coking the
chambers 14 are closed by coke overn doors 20
(FIG. 4). The coking chambers 14 are separated from
each other by heating walls indicated generally at
22. Each heating wall is typically formed from
courses of silica bricks, there being hundreds of
bricks to each course. Each of the heating walls is
provided with a plurality of flues 24 which
typically are alternated between heating cycles and
drafting cycles. The floor of the coking chambers
14 as well as the heating walls 22 are supported by
pillar walls 26 (FIG. 3). The space between the
pillar walls are used for regenerative purposes and
are typically filled with checker bricks 28. Heated
air and gas are introduced into the flues through
nozzles 29 at the bottom of the flues and are
ignited, the burning gas in turn heating the heating
walls to a temperature typically i:n the range of
2100 to 2500 degrees Fahrenheit.
In a typical cycle of operation of a coking
chamber, coal will be introduced into the chamber
from charging holes or openings 30 (FIG. 2) and then
levelled. The chamber is then sealed, and the coal
within the chamber is heated for an extended period
of time, typically 24 hours, to dr_~ve the volatiles
x
from the coal. When the coking cycle for a
particular coking chamber is completed, the doors 20
are removed by a door mechanism 31 and then a pusher
(not shown), is introduced from the pusher side into
the coking chamber to push the coke within the
coking chamber from the coking chamber, the coke
being discharged over a coke guide 32 and onto a
quenching car 34. At the time that the doors are
removed, cold air will rush into the coking chamber
rapidly cooling the surface of the bricks. In
addition, liquor from within the collecting main 12
may be drawn from the main through a standpipe 36
which is associated with the coking chamber, which
liquor may in turn spall the surface of the silica
brick of the heating walls adjacent the coking
chamber which is being discharged.
It should be noted at this point, that the
foregoing structure of the coke oven battery and
manner of operation of it is well known in the art.
A by-product coke oven battery of 'the type somewhat
schematically illustrated in this <~pplication is
more fully disclosed in GB 511,320..
An on-going problem in the opf~ration of a
by-product coking oven battery is i=he progressive
deterioration of the heating walls between the coke
oven chambers. In the past it has been the practice
to initially repair a heating wall by shutting off
the air and gas flow to the heating wall so that
there is no combustion within the f=lues, to insulate
the area which is to be repaired by placing
bulkheads 38 (FIG. 4) in the two coking chambers to
either side of the heating wall which is to be
repaired, and to place wall insulation 40 on the
_8_
surface of the adjacent heating walls. While this
general type of repair is satisfactory in some
situations, it is sometimes necessary to rebuild an
end of a heating wall. This is accomplished by
tearing down the brickwork of that: portion of the
heating wall which is to be repaired, replacing
damaged bricks, and rebuilding the heating wall.
Because of the large number of bricks which are
employed in a heating wall, this is a very
time-consuming process, typically taking
approximately two to three weeks t.o complete.
Recently a new silica-based m.ix has been
developed which is the subject of U.S. Patent
4,506,025. This material has been proposed for use
as a replacement of silica bricks.
It should be appreciated that even though this
material has high dimensional stability and good
thermal shock resistance in the temperature ranges
which may be encountered by a brick within a coke
oven, the large number of bricks which would have to
be utilized would still require an extensive repair
time. In addition, it will be necessary to very
carefully mortar the many adjacent surfaces of the
bricks if made in a conventional design, such as
that shown at FIG. 14 which shows the bottom course
of bricks in a heating wall.
In accordance with this invention a novel cast
module is formed from a material o.f the type
disclosed in the foregoing U.S. Patent 4,506,025,
the cast module of this invention encompassing at
least one entire flue from one side' of the heating
wall to the other side, and preferably encompassing
three flues in the manner indicatec9 in FIG. 7.
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Thus, in accordance with this inverntion, novel cast
repair modules are provided for us;e in the repair of
heating walls between coke oven chambers. A variety
of differing modules are provided, there being a
bottom module 50, a lower intermediate module 52, an
upper intermediate module 54 (FIG. 13), and a top
module 56. Each of the various modules 50 through
56 are a generally rectangular parallelpiped having
first and second opposed side walls 58, 60, (FIG.
11) the side walls being spaced apart from each
other a distance substantially equal to width of a
heating wall. The modules additionally have first
and second opposed generally vertically extending
ends terminating in surfaces 62, 64. The first end
is adapted to be disposed at one e:nd of the heating
wall and has a vertical end surface 62 which
conforms to the vertical end surface of the heating
wall being repaired. The second end has a centrally
located protrusion 64.1 which is adapted to interfit
with old brickwork in the manner best illustrated in
FIG. 7. Each module additionally lzas upper and
lower generally horizontal surfaces 66, 68,
respectively. The lower horizonta:L surface 68 of
the bottom module 50 is generally planar and is
adapted to rest upon the upper horizontal surface of
the pillar walls 26. The upper horizontal surface
of the bottom module as well as thE~ upper horizontal
surface 68 of the lower intermediate modules 52 and
upper intermediate modules 54 are provided with
transversely spaced apart longitud_~nally extending
V-shaped grooves 70 best seen in F7:Gs. 7 and 11.
Each of the V-shaped grooves 70 is adapted to
receive a corresponding V-shaped projection 72 (FIG.
~~~~~,~ ~~~
y,su;-dye:
- to -
9) carried by the lower surface of an adjacent
module 52, 54, or 56. In addition vertically
extending apertures may be provided in mating
adjacent modules, which vertically extending
apertures may receive dowel rods 74 formed of the
same material as the modules themselves. These
dowel rods will further cause the modules to be
properly aligned with one another when they are
assembled into a heating wall in the manner which
will be more fully brought out below.
Each of the modules in the preferred embodiment
shown in the drawings is three flues in length,
which length is typical of the length which needs to
be rebuilt in a conventional coke oven battery
adjacent the end of a heating wall. Thus, the
module may be approximately 76 inches in length, 24
inches wide, and 12 inches high, the overall weight
being approximately 1,700 to 1,800 pounds. The
bottommost module will rest on the horizontal
surface of the pillars and surround the nozzles 29.
In order to prevent the nozzles from becoming
plugged with mortar as the modules are mortared, one
on top of the other, it is necessary to provide the
bottom module 50 with clean out ports 76 (FIG. 7) ,
which ports may extend to either side of the module.
The lower intermediate modules are provided with
three flues 24 in the preferred embodiment, the flue
adjacent the first end (to the left in FIG. 7) not
being provided with an air-port def=fining structure
78 while the second and third flues are, which
air-port defining structures are of the same
material and integral with the balance of the
module. It should be noted that ai.r-port defining
x~ , s~ .~ ~3 a-~ il
i~ ~~ ~;d ~?r: r.o rte
- 11 -
structures are well known in the prior art but are
typically formed of fire clay or t:he like and are
separate and distinct from the silica bricks which
make up the heating wall. The purpose of the air
port defining structures is to provide additional
air for combustion purposes above the base of the
flue so that there will be uniform heating of the
flue throughout its entire vertical length. Thus,
rich fuel gases are provided to the lowermost nozzle
29 through a fuel gas line 80 and air is provided
through separate air line 82 to the lowermost nozzle
29, there being insufficient air to permit all of
the fuel delivered to the lowermost nozzle to be
consumed. However, the air delivered by the
air-port defining structure 78 will permit the fuel
delivered to the nozzle be totally consumed a point
further up the flue, therefore permitting relatively
uniform heating of the entire vertical extent of the
heating wall. The upper intermediate modules 54
differ from the lower intermediate modules simply by
the omission of the air-port defining structure
within the second and third flues. The uppermost
module 56 (FIG. 13) is provided with a crossover
passageway 84 which permits the fuel in a heating
flue to be drafted down an adjacent flue. For
example, with reference to FIG. 13, if the left-hand
flue 24.1 is in a burning cycle thf~n the flue 24.2
to its right would be in a drafting cycle and gas
from the flue 24.1 would pass through the crossover
passageway 84 in the top module 56 and then down the
drafting flue 24.2. This burning/drafting cycle
will be reversed periodically, for example, every
half hour, to provide for more uniform heating of
4
~~s.'~~ ~~~,,~
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the brickwork within a heating wall and this design
feature is conventional with coke oven batteries of
the type disclosed.
By employing the repair modules of this
5 invention, it can be seen that there are far fewer
air passageways for leaking of volatile by-products
from the coking process into the flues, the only
passageways being the horizontal surfaces between
the modules, which horizontal surfaces are provided
with V-shaped grooves to prevent the flow of
volatile by-products from the coal into the flues.
It should be appreciated if such by-products were to
flow, that they could cause erosion and/or burning
of the bricks in these areas as the volatile
by-products are combustible when placed in an oxygen
environment. Thus, it is desirable that all of the
volatile by-products be discharged through
standpipes 32 at the top of the coking ovens rather
than being permitted to leak through the modules or
brickwork into the flues. Additionally, it can be
appreciated from a comparison of FIGS. 7 and 14 that
it will be much easier to mortar the modules of this
invention than it is the prior art brickwork.
In order to make the modules of this invention,
a form is mounted on a shaker table, filled to an
appropriate level with a slurry of the castable
refractory, the slurry then being ;shaken to
eliminate all bubbles and to ensure proper mix.
After slurry material has initially set up, the
material is removed from the mold and is placed into
an oven where it is baked at progr<~ssively higher
temperatures for a period of time. Thus, the
temperature of the oven is increasE~d from ambient to
'~ ~, n5 ~% ~ ~~
F..i~~._r(dt sr
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950°C by approximately 50° per hour. By slowly
raising the temperature during they preliminary
baking of the modules, it has been. found that a very
satisfactory product can be achieved, which product
is very thermally stable during the normal operating
temperatures of the coke oven battery.
A method for repairing the damaged end of a
heating wall in accordance with the principles of
this invention and utilizing the cast modules of
this invention will involve the steps set forth
below. However, while a preferred sequence of steps
is set forth below, it should be appreciated that
the sequence may be varied somewhat in accordance
with the preferences of the individual contractor.
For convenience of description of the method, it
will be assumed that the bricks which surround the
last three flues of a heating wall adjacent the coke
side of a coke oven battery are to be repaired.
Initially, the coke oven doors on the coke side of
the battery for the two coke oven chambers adjacent
the heating wall which is to be repaired will be
removed. The frames for the coke oven doors will
also be removed. In order to facilitate the working
in this area, an insulating bulkhe<~d 38 will be
erected in each coke oven chamber <~djacent the
heating wall to be repaired, the bulkhead extending
from the floor to the ceiling and between the walls
of each chamber. After the bulkheads have been
erected, the side walls of the heat=ing walls
immediately adjacent the heating wall to be repaired
are also covered with insulation. Next, the
buckstay 88 (FIG. 4) adjacent the end of the heating
wall to be repaired will be cut through at floor
a~~~~~U
- 1.4 -
level and adjacent the top of the area to be
repaired and removed. In this connection, it should
be noted that the ends of each heating wall are
provided with buckstays disposed on the outside
surface of the coke oven battery, the base of the
buckstays being embedded in the foundation of the
coke oven battery, and the tops of the buckstays for
each heating wall being tied together by tie rods
(not shown). After the buckstays have been removed,
it is then necessary to hang the roof above the area
where the heating wall is to be removed. To
accomplish this, an upper course of silica bricks is
very carefully removed. A plurality of support
beams 90 are then placed on top of the battery as
best shown in FIGs. 3 and 5. A threaded rod 92 is
passed through a centrally located aperture in each
of the support beams 90. The threaded rod passing
through inspection ports 94 in the old brickwork. A
nut 96 is provided at the upper end of each of the
threaded rods 92 to limit its downward movement.
After the rods have been suitably positioned, a nut
98 and washer 100 are mounted on tlae lowermost end
of each of the rods as shown in FIG. 6. A retainer
plate 102, having a keyhole aperture 104, is
provided for each rod 94, the plate being positioned
with respect to the rod 94 and washer 100 so that
initially the plate can be passed above the washer
and moved at an angle thereto so that the plate can
be supported by the washer as can t>est be
appreciated from inspection of FIG:. 3, 5, and 6.
The nuts 96 and 98 are then suitably tightened so
that the retainer plate 102 will bear against the
ceiling. Additional braces (not shown) may be
- 15 -
provided which extend from either side of the top of
the old heating wall to the adjacent heating walls.
After the roof has been propE~rly hung, the
remainder of the old brickwork is removed in the
area of the heating wall which is to be repaired.
The bottom gas nozzles are then plugged in a
conventional manner to prevent the introduction of
any mortar into the gas nozzles.
At this time it is also necessary to properly
prepare the old brickwork which i:~ to be positioned
adjacent the new modules. To this end, the old
brickwork will be built up at lea~;t to the height of
the module which is to be inserted, the old
brickwork being properly cut to receive the
projecting central portion 64.1 which is best shown
in FIG. 7. The entire face of the old brickwork can
be properly prepared at this point in time, but more
typically only a sufficient amount of the old
brickwork will be suitably prepared as will be
necessary to properly receive the next module. This
will facilitate the mortaring of the modules which
are to be installed to the old brickwork.
After the floor area is suitably prepared and
mortared to a generally planar surface, a bottom
cast repair module is inserted, the bottom repair
module, for example, being discussed having three
spaced apart vertical flues which a xtend upwardly
from a generally lower horizontal aurface, the flues
being spaced away from each other <~ distance equal
to the distance between the gas nozzles. As
previously indicated, the bottom module is provided
with side clean out ports. The top surface of the
bottommost module is then provided with a layer of
z~~~~~~
- 16 -
mortar and then a lower intermediate module is
positioned on the bottom module. Each of the
modules is quite large and heavy, and therefore the
positioning is typically done by a forklift truck
which raises the module to the desired elevation so
that it can then be slid into its final position
where the V-shaped grooves 70 will receive the
V-shaped projections 72 of the uppermost module.
After a suitable number of lower intermediate
modules have been placed into position, it is then
only necessary to continue building up the heating
wall by then installing additional upper
intermediate modules. Finally, when the proper
height has been built up, a top or crossover module
56 is then positioned in place. When all of the
modules of this invention have been installed, it is
only necessary to reinstall the uppermost courses)
of brickwork which have been reserved for this
purpose and to properly mortar the parts in place.
When the mortaring is complete it is desirable
to reach into the lowermost module through the clean
out ports and remove any mortar which may have
fallen onto the tops of the plugs which had been
installed on the gas ports and also to remove the
gas plugs. Now it is only necessary to reinstall
the buckstay which was removed prior to the
installation of the repair modules,. to install the
door frames which were removed prior to the repair
of the heating wall, to remove the bulkhead and side
wall insulation, and to reinstall t:he coke oven
doors which were removed prior to t:he repair of the
heating wall.
CA 02034230 2000-12-08
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While a preferred form of this invention has
been illustrated a.nd discussed above, as well as a
preferred method of installation, it should be
appreciated that other variations may occur to those
S having ordinary skill in the art. Therefore,
applicant does not intend to be limited to the
particular details illustrated and described above.
