US2851760A - Patching of by-product coke oven tubular surfaces - Google Patents

Description

Sept. 16, 1958 H. E. TAYLOR PATCHING 0F BY-PRODUCT COKE OVEN TUBULAR SURFACES Filed March 15. 1954 2,851,760 PATCHING OF BY-PRODUCT COKE OVEN TUBULAR SURFACES I Filed March 15, 1954 H. E. TAYLOR Sept. 16, 1958 5 Sheets-Sheet 5 United States Patent PATCHING OF BY-PRQDUCT COKE OVEN 1 TUBULAR SURFACES Harold Ernest Taylor, Norristown, Pa., assignor to Alan Wood Steel Company, Conshohocken, Pin, a corporation of Pennsylvania Application March 15, 1954, Serial No. 416,366 7 Claims c1. 25-1555 The present invention relates to the repair of by-product coke oven guns.

A purpose of the invention is to permit continued operation of by-product coke ovens at high efliciency after gas guns have begun to leak.

A further purpose is to permit rapid and economical repair of leaks of gas guns and other tubular refractory passages of by-product coke ovens while the refractory is still hot and without withdrawing the bank of ovens from service.

A further purpose is to permit deep penetration of refractory patching material in crevices of gas guns of by-product coke ovens so that a repair will be achieved which will restore the refractory to complete gas tightness, and permit normal response to expansion and contraction.

A further purpose in the repair of gas guns and other tubular passages in the refractory of by-product coke ovens is to dam the gun by inserting a plastic dam and squeezingthe two ends of the dam relatively toward one another.

A further purpose is to close the nozzles of the gas guns of a by-product coke oven by extruding plastic plugging material into such nozzles from the gun.

A further purpose is to insert a dispersion or slurry of leak-sealing refractory material preferably silica, into the tubular opening of the gun under a positive pressure, and preferably to guard against excess pressure by discharging an overflow through a safety valve.

A further purpose is to restore the gun to operation by removing the excess of slurry, removing the dam and the plugs, machining the tubular opening to predetermined size and removing any foreign material.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate one only of the numerous embodiments in which my invention may appear, selecting the form shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figure 1 is a vertical section transversely of a bank of coke ovens at the fuel gun location, the figure being taken on the line 1-1 of Figure 2.

Figure 2 is a vertical section extending longitudinally of the bank of coke ovens, the section being taken on the line 2-2 of Figure 1.

Figure 3 to 12a are step-wise views showing the process of the invention applied to repairing the fuel gun of a by-product coke oven.

Figure 3 is an enlarged fragment of Figure 1 showing the introduction of the dam.

Figure 4 is an enlarged fragment of Figure 1 show ing the expansion of the dam.

Figure-5 is an enlarged fragment of Figure 1 showing the dam expanding tool removed and showing the extrusion of plugging material into the nozzle.

Figure 6 is an enlarged fragment of Figure 1 showing the smoothing of the nozzle plug.

Figure 7 is an enlarged fragment of Figure 1 showing the nozzle plug completed.

Figure 8 is a side elevation partly broken away showing the tank of slurry connected to the end of the fuel gun for introduction of the slurry.

Figure 9 is an enlarged fragment of Figure 1 showing the slurry entering the fuel gun and filling a crack in the refractory.

Figure 10 is an enlarged fragment of Figure 1 showing excess slurry discharging through the safety valve.

Figure 11 is an enlarged fragment of Figure 1 show ing the removal of the dam and of one of the plugs.

Figure 12 is an enlarged fragment of Figure 1 showing the machiningof the gun to predetermined size.

Figure 12a is an enlarged fragment of Figure 1 showing the blowing out of foreign material from the gun prior to restoring the coke oven to service.

In the drawings like numerals refer to like parts throughout.

By-product coke ovens are generally constructed of silica refractory brick. The service is severe, since each oven is subjected to a succession of cycles involving heating up and cooling down of the refractory parts. Generally a bank of by-product coke ovens will give many years of service. One of the limiting factors, however,

is leaking of the fuel guns, which may cause fuel gases to mix prematurely withwair or to comingle with products of combustion, reducing the eficiency of operation.

The problem of repair of such fuel gas guns is complicated by the fact that the refractory remains hot, and any method of repair which does not permit repair of an individual oven while its refractory remains hot and adjoining ovens are in operation would be prohibitively expensive.

The present inventor has discovered that eifective and long-lasting repairs of fuel gas guns of by-product coke ovens can be accomplished during a very short period of interruption of operation of a particular oven, and without giving up normal operation of adjoining ovens. Thus the patching is done in contact with hot refractory, without further damaging the refractory, and to produce a repair which behaves similarly in expansion and contraction to the original refractory.

In accordance with the invention, a dam is inserted to close off any part of the fuel gas gun which does not require repair, and the fuel nozzles are plugged. Thus the portion of the gun to be repaired is isolated. Liquid dispersion or slurry of patching material is introduced into the fuel gas gun under pressure so that it will penetrate the crevices. The slurry desirably consists of finely divided silica or Hatfield clay which is about SiO balance impurities, and suitably of a fineness below mesh per linear inch. This is made up with water in a slurry, conveniently employing about three volumes of dry silica flour or the like.

In order to avoid excessive pressure, a simple safety valve or release valve is employed so that when a predetermined pressure is built up the excess slurry will run out and indicate that the pressure is adequate. This also serves as a release for steam.

It is then merely necessary to remove the excess of Y slurry, and after allowing a few minutes for the repair to harden, eliminate the dam, and the plugs, and machine the fuel gas gun back to size. Foreign material such as remnants of the dam and the plugs and excess of the silica can conveniently be removed by blowing.

Considering now the construction in detail, supporting structure 20 mounts refractory walls which form a series of coke ovens 21 and intermediate regenerators 22.

Each oven has two regenerators, which are separated at the longitudinal middle of the bank of ovens. On each side of the bank of ovens is a fuel "gas main running longitudinally of the battery and connected to one of the generally horizontal fuel gas guns 23 which runs half way across the battery to the center line of the oven. The fuel gas guns 23 consist of refractory shapes 24, which are suitably of silica brick connected end to end by interlocks 25, having longitudinal bores which form the gun, and having lateral openings 26 at the top which receive fuel nozzles 27 which discharge the fuel upwardly into vertical flues 28, which in the combustion phase of the cycle contain air introduced through regenerator ports not shown. The combustion gas passes up through the fines and across through passage 30 to the regenerator at the opposite end of the oven, Where the combustion gas passes down through the fines and out through the gun to heat the regenerator. Inspection and access through the top is permitted to each flue through openings 31, passages 32 and openings 33 as well known. Also as well known decarbonizing air is introduced through the off-gas gun for the purpose of decarbonizing the gas nozzles.

The reversal of cycle between the regenerator which is undergoing combustion of gas and the regenerator which is absorbing heat suitably occurs about every half hour, and therefore it will be evident that the change in temperature in the fuel gas guns is very violent, especially near the outside of the oven. The refractory brick of the guns undergo high volumetric expansion and contraction and therefore there are likely to be failures of two kinds. Individual shapes may pull away from one another and the refractory cement joining them at the ends may open up, causing leaks. In the second place, since internal stresses of high magnitude develop in the refractory shapes, the fuel gas gun shapes themselves may crack. The resulting leakage reduces the intensity of combustion and reduces the effective amount of air for combustion.

As many of the cracks developed extend laterally to considerable depth or entirely through the fuel gas gun shapes, it has been impossible to effectively seal them by merely swabbing with plastic refractory material, as has been attempted in the prior art.

In order to accomplish the repair in accordance with the process of the invention, the individual coke oven gun undergoing repair is temporarily taken off service. The gas is shut off from the gun which is to be patched, and the decarbonizing cap casting is taken off, as well as the connection or closure at the end of the gun.

It has been found that the cracks requiring plugging are generally located close to the outside end of the gun, and therefore it is desirable in most cases to insert a dam so that it will not be necessary to plug all of the nozzle openings. Depending on the experience in the particular battery of ovens, the dam may be located at a position beyond the second, third, fourth or some other nozzle from the outside.

It will be understood, however, that according to the broader aspects of the invention, all nozzle openings could be plugged, in which case the dam would be unnecessary.

Considering first Figure 3, a damming tool 34 is inserted through the gun from the outside end. This tool desirably includes a first abutment 35, which is desirably of wood so that it can burn out during the operation. There is an opening through the center of the first abutment through which extends a metallic rod 36 having a handle 37 at the end outside of the gun. The rod 36 is threaded at the end to receive a nut 38 beyond the abutment and desirably imbedded in the abutment 35 so that it can be unscrewed by turning the handle 37 due to the frictional engagement of the abutment with the dam and the gun.

On the side of the abutment 35 toward the handle end of the rod is a second abutment 40, which, like the first abutment, substantially fills the gun opening and has a central opening 41 through which the rod 36 passes to the handle. The second abutment is desirably of metal and is mounted on the side remote from the first abutment on a tube 42 which surrounds the rod and outside the gun carries a handle 43.

Before the damming tool is inserted in the gun, a suitable fabric tube or stocking 44 is placed around the rod between the abutments and filled with a charge of damming material 45 which is conveniently a commercial plastic heat insulation such as a mixture of asbestos fibers and plastic clay or any other suitable plastic heat insulation or refractory cement. The ends of the stocking are desirably tied or otherwise secured to the rod to hold the charge of plastic material 45. The damming tool is inserted to the desired position as shown in Figure 3 and then the abutments are pushed together. This is done by holding handle 37 and pushing on handle 43. The etfect is to expand or extrude the plastic damming material into plugging engagement with the wall of the gun. At the same time, the stocking 44 and the abutment 35 desirably begin to burn. The rod 36 is now unthreaded from the nut 38 and the rod is withdrawn, its opening being filled by the plastic damming material which relieves its pressure to close the opening. The rod 36, the abutment 40 and the tube 42 are then pulled out, leaving the gun closed by a dam 46 at the inner end of the zone to be patched.

It is desired to have a friable material at the dam so that it can readily be removed later and for that reason high asbestos content is desirable.

The next step is to close off the flue nozzles which are located between the dam and the outer end of the flue gas gun. This is done by extruding or squeezing heat insulation cement or refractory cement into the openings, desirably using an extrusion device 47 as shown in Figure 5 which has a chamber 48 containing plastic material subjected to pressure from a plunger 50 by a rod 51 advanced by a screw or other suitable device from outside the flue gas gun. The nozzle at the end is bent upward at 52 and introduces a charge of plastic cement 53 into the lower part of each flue gas nozzle 27. This plug 53 is desirably smoothed off and pressed upwardly by a smoothing trowel 54 on a long handle 55. The final result as shown in Figure 7 is to close off openings except leak openings from the flue gas gun in the area to be patched.

The next step is to introduce the slurry or dispersion of patching material. The slurry is contained within a tank 56 provided with a stirrer 57 to keep the finely divided silica in suspension in the water. A discharge tube 58 extending to a position near the bottom of the tank connects through a suitable hose and valve 60 and a pressure gage 61 to a face plate 62 which is fastened to pipe connection 63 on the end of the flue gas gun.

A source of suitable pressure, for example compressed air, is connected through pipe 64, valves 65 and pressure regulator 66 to the top of the slurry in the tank, and the pressure is regulated to a predetermined value. Good results have been obtained with an air pressure of about 7 to 10 p. s. i., as it is not desired to burst the refractory.

A safety valve is provided at the decarbonizing opening 67 by applying a weight 68 which is desirably selected to insure the desired pressure on the slurry in the flue gas gun, suitably about 2 p. s. i., since of course part of the air pressure is used to raise the slurry to the flue gas gun. When the slurry fills the flue gas gun and reaches the predetermined pressure the weight 68 rises as shown in Figure 10 and discharges the excess slurry, thus indicating that the proper pressure has been reached and also that the flue gas gun has been filled with the slurry. It will be understood that the exact pressures will vary with the particular installation.

The weight 68 also allows for escape of steam which is likely to form from the heat in the refractory.

Once the space to be filled inthe flue gas gun has been adequately filled, thus forcing the slurry into crack 70 to be repaired, the slurry flow is turned olf by closing valve 60.

with the other foreign solid material.

As the walls of the flue gas gun are very hot, the refractory sets quickly to a firm consistency and the excess can be removed after a few minutes by opening valve 59 in a T connection. A few additional minutes may desirably be allowed to permit the refractory to further harden in the cracks, and then the excess of solid material and the plugs and dam are taken out.

Pusher rods 71 are forced through the nozzles from the top as shown in Figure 11 to discharge the plugs 53. The friable dam 46 is removed as shown in Figure 11 desirably by a reamer 72 driven by a power drill 73. The

abutment 35 by this time will be charred so that it will disintegrate, or burnup, and the nut will be removed The gun opening is. then reamed or abraded to the desired size to remove the skin of excess refractory which is formed on the inside as by a wire brush or other suitable tool 74 driven by a drill 73 or the like. I

The last step is normally to introduce an air blast through nozzle 75, Figure 12a, which blows out any remaining foreign material from the gun.

It will be evident that the resultant leak-sealing gives a structure which will have substantially the same expansion and contraction as the silica refractory itself and will be capable of remaining in service for a long' period of time.

The gas riser can then be unplugged and the decarbonizing face plates replaced to put the oven back in service. The gas can then be turned on the gun.

The entire operation can be carried out in a period of approximately one hour for a single gun.

The result of the patching operation is a great saving in gas and accordingly a great economy in operation.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the process shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. The process of patching tubular walls of a by-product coke oven during operation of a battery of ovens, which comprises interrupting the normal operation of the gas gun of an individual oven while the refractory is still hot, introducing into the gun a plastic darn, squeeezing the opposite ends of the dam relatively toward one another and thereby expanding the dam into engagement with the walls of the gun, plugging the nozzles from the gun which are located between the dam and one end of the gun, thereafter introducing a slurry of leak sealing material into the space within the tubular refractory walls to be repaired from one end thereof under a pressure which forces the leak sealing material into the crevices, removing the excess of slurry by way of the same end of said space and removing the dam and the plugs.

2. The process of sealing leaks in tubular refractory walls of a by-product coke oven which is part of a battery of coke ovens which are in operation, which comprises discontinuing the normaI' operation of the gas gun of an individual coke oven of the bank, while the refractory is still hot, inserting a plastic dam into the gun opening, squeezing the opposite ends of the dam and thereby outwardly expanding the dam into engagement with the walls of the gun, plugging the ports extending laterally from the tubular opening to be patched, introducing in the tubular opening in contact with the hot refractory a slurry of leak sealing material under pressure and thereby forcing the leak sealing material into the crevices, removing the excess slurry, removing the dam, and removing the plugs.

3. The process of claim 2, in combination with finally machining the tubular opening to predetermined size.

4. The process of claim 2, in which the slurry is forced into the tubular opening under a predetermined pressure maintained in the tubular opening, and when that pressure is reached, excess of slurry is discharged through a relief valve.

5. The process of filling leaks in the fuel gas gun of a by-product coke oven which is at elevated temperature, which comprises withdrawing the gas gun of the individual coke oven from normal operation, introducing into the gun opening a plastic dam, squeezing the opposite ends of the dam relatively toward one another and thereby expanding the dam into engagement with the walls of the gun, plugging the nozzles from the gun which are located between the dam and the inlet end of the gun, forcing suspension of leak-sealing refractory material into the gun and thereby into the crevices to seal the leaks, removing the excess of leak-sealing material in liquid form, removing the darn, removing the plugs from the nozzles and machining the gun opening to predetermined diameter.

6. The process according to claim 5, in which the suspension of leak-sealing refractory is forced into the gun until the predetermined pressure is reached and then the excess of the dispersion is discharged through an overflow.

7. The process of patching the walls of a tubular byproduct coke oven passage while at elevated temperatures and without stopping operation of the entire group of ovens which comprises: taking the particular passage temporarily out of normal operation; introducing a plastic dam into the passage from an end thereof to a point removed from any end; squeezing the opposite ends of the dam and thereby expanding the dam into engagement with the walls of the passage and creating pressure to fill any holes that may exist in the dam and thus forming a complete block across the entire passage; inserting from the same originally mentioned end plugs into any lateral openings that may exist between the dam and that end; thereafter introducing from the same end a slurry of leak sealing material under pressure into contact with the hot refractory of the passage; when the pressure reaches a given amount, opening a valve located at that same end to discharge excess slurry therethrough; completing with-' drawal of excess slurry in the liquid form from that same end; removing the dam; removing the plugs from the lateral openings; and machining the said passage to remove any solidified excess of sealing material.

References Cited in the file of this patent UNITED STATES PATENTS 1,736,293 Van Denburg Nov. 19, 1929 2,504,185 Debenham Apr. 18, 1950 2,564,009 Hyche Aug. 14, 1951 2,618,014 Sawyer et a1. Nov. 18, 1952 2,763,910 Braatelien Sept. 25, 1956 FOREIGN PATENTS 6,507 Great Britain Mar. 17, 1904 142,419 Great Britain May 6, 1920

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