CA2034230C - Coke oven repair - Google Patents

Abstract

A repair of the damaged end of a heating wall of a coking oven, which improved repair includes utilization of a novel cast refractory module which may be utilized to replace existing silica bricks within the damaged coke oven heating wall. The novel cast refractory module is a unitary structure formed from a castable refractory material having very high dimensional stability over a wide range of temperatures. Each repair module is a rectangular parallelpiped having vertically extending flues formed therein, one end of a module being adapted to conform to the end shape of the damaged heating wall, the other end of the module being adapted to interfit with existing brickwork. The modules are assembled by initially removing damaged brickwork from the damaged heating wall and then placing in the new modules which are mortared in place.

Description

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 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 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 ~~~?~

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.

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 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.

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 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 ~~s.'~~ ~~~,,~

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 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 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~~~~~~

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.

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.

Claims (3)

1. A first repair module for a coke oven comprising:
a large size cast monolithic refractory repair module for use in the repair of existing heating walls between coking chambers in a coke oven battery, each heating wall being built from a plurality of courses of bricks, each course of bricks including a plurality of small size refractory bricks which are used to form wall surfaces of adjacent coking chambers and to define spaced apart vertically extending flues within the heating walls, which flues may be used alternately for burning fuel gases or for drafting, the flues having tops and bottoms, each flue having a gas nozzle and an air port at the bottom thereof, the large size cast module being formed from a castable refractory which, when cast, has high dimensional stability and good thermal shock resistance in the temperature range. which may be encountered in a coke oven, the large size cast module being a generally rectangular parallelepiped having first and second opposed vertically extending sidewalls spaced apart from each other a distance substantially equal to the width of the heating wall at the location of the repair, said sidewalls being capable of forming the wall surfaces of adjacent coking chambers, first and second opposed generally vertically extending ends, and upper and lower generally horizontal surfaces, the distance between the horizontal surfaces being at least equal to one course of bricks, and the large size cast monolithic refractory repair module having at least one vertically extending flue defining cavity extending upwardly from the lower generally horizontal surface to the upper generally horizontal surface.

2. A first repair module for a coke oven as set forth in claim 1 wherein one end of the first cast repair module is adapted to be disposed to one end of a heating wall, the module having a vertical end surface which conforms to the vertical end surface of the existing heating wall being repaired, and wherein the second end of the first cast repair module is adapted to form one surface of a flue in the heating wall.

3. The first large size cast repair module as set forth in claim 1 wherein the first cast module is provided with two or more vertically extending flue defining cavities.