Coke oven repair methods

Abstract

To provide a maintenance method for preventing damage to bricks in a non-repair part during reconstruction maintenance of a coke oven where multiple neighboring combustion chambers are simultaneously dismantled.SOLUTION: In a coke oven having an arrangement in which multiple combustion chambers and coke oven chambers are alternately aligned, after removing bricks constituting four or more adjacent rows of combustion chambers among the combustion chambers, a support pillar supporting a larry car rail installed on the furnace top part of the coke oven is installed at a position where a distance from the center of the combustion chambers adjacent to a space part generated by the removal of the bricks in the arrangement direction of the space part is four times or less than the sum of the width of each combustion chamber in the arrangement direction and the width of each coke oven chamber in the arrangement direction, and then, a brick structure is reconstructed with new bricks in the space part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for repairing a coke oven, and more particularly to a method for replacing a brick structure that constitutes a combustion chamber. [Background technology]

[0002] Coke ovens are structures made of bricks. For example, in horizontal-chamber coke ovens, the coke chambers into which coal is charged and the combustion chambers that supply heat to the coke chambers are arranged alternately, and below the coke chambers and combustion chambers there are heat storage chambers that recover heat from the combustion exhaust gas and preheat the air and fuel gas used for combustion.

[0003] The combustion chamber is sandwiched between carbonization chambers on both sides. The combustion chamber is constructed entirely of bricks, and the bricks facing the space inside the carbonization chamber form the furnace walls of the carbonization chamber. In the combustion chamber, fuel gas is burned in a flue made of bricks inside, and the temperature of the combustion chamber is raised to approximately 1000 to 1300°C. This supplies combustion heat to the coal charged in the carbonization chambers on both sides via the combustion chamber bricks facing the carbonization chamber (the furnace wall bricks of the carbonization chamber), and the coal is carbonized using this heat.

[0004] Once heating begins, a coke oven will continue to operate for over 30 years without stopping. During this continuous operation, the bricks gradually deteriorate, and if the deterioration is severe, the combustion chamber itself may become unusable.

[0005] Therefore, to ensure stable and continuous operation of the coke oven, repairs are carried out to replace deteriorated bricks with new bricks. This brick replacement is a repair method in which combustion in the combustion chamber corresponding to the deteriorated part is stopped and cooled, and then the old bricks are dismantled and removed, and new bricks are used to rebuild the same structure as before the dismantling. For example, the method shown in Patent Document 1 is known.

[0006] That is, Patent Document 1 discloses a method for simultaneously replacing multiple adjacent combustion chamber structures in order to improve the efficiency of repair work. The technology described in Patent Document 1 is a method for replacing only the kiln mouth, i.e., the end of the combustion chamber on the pusher side or the coke outlet side. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-31581 Summary of the Invention [Problem to be solved by the invention]

[0008] The method described in Patent Document 1, in which multiple adjacent combustion chambers are simultaneously dismantled and rebuilt, offers advantages such as a larger work space for efficient work and effective insulation to maintain a high temperature in the unrepaired sections that will not be demolished. Recently, brickwork re-building repairs have been performed, in which the entire combustion chamber sandwiched between two coking chambers, i.e., from the extruder side to the coke outlet side, is demolished and a new combustion chamber is constructed in its place. As a result, when a large portion of a single combustion chamber is demolished, and four or more consecutive rows of combustion chambers are demolished simultaneously, a new problem arises: progressive damage to bricks in the unrepaired sections near the demolished sections. This brick damage can be caused by a tendency for the unrepaired sections to temperature drop. However, even when the insulation of the unrepaired sections is strengthened to prevent temperature drop, brick damage is often not prevented.

[0009] That is, an object of the present invention is to provide a repair method that prevents damage to bricks in non-repaired areas when carrying out re-stacking repairs on coke ovens, in which multiple adjacent combustion chambers are simultaneously dismantled. [Means for solving the problem]

[0010] 1. A method for repairing a coke oven having a plurality of combustion chambers and carbonization chambers arranged alternately, comprising removing the constituent bricks of the brick structure constituting the combustion chambers and replacing them with new constituent bricks, After removing the bricks constituting four or more adjacent rows of the combustion chambers among the combustion chambers, a support for supporting a coal car rail installed at the top of the coke oven is installed at a position where the distance from the center of the arrangement direction of the combustion chambers adjacent to the space created by removing the bricks is four times or less the sum of the width of each of the combustion chambers in the arrangement direction and the width of each of the carbonization chambers in the arrangement direction, Next, a brick structure is reconstructed in the space using new bricks. How to repair a coke oven.

[0011] 2. A method of repairing a coke oven described in 1, in which the height of the top of the pillar is adjusted so that the difference between the height of the support portion of the coal car rail supported by the pillar and the height of the coal car rail at the end of the arrangement direction of the non-repaired portion adjacent to the space portion is ±5 mm or less.

[0012] 3. Adjust the height of the top of the pillar so that the difference in maximum stress between the pillar and the unrepaired section when a coal car passes over the coal car rail is within ±5%. 3. The method for repairing a coke oven according to 1 or 2 above. [Effects of the Invention]

[0013] According to the repair method of the present invention, even in the case of coke oven re-repair in which multiple adjacent combustion chambers are simultaneously dismantled, it is possible to prevent damage to bricks in the non-repaired sections. As a result, by carrying out repairs on multiple combustion chambers simultaneously, it is possible to shorten the construction period and reduce costs. In addition, it is now possible to carry out re-repairs in which multiple adjacent combustion chambers are simultaneously dismantled while producing coke in the non-repaired sections of one oven battery, which has the effect of increasing coke production. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a conventional method of reloading and repairing a coke oven. [Figure 2] 1 is a diagram showing an embodiment of reloading and repairing a coke oven according to the present invention. FIG. [Figure 3] FIG. 10 is a diagram showing the structure of a support pillar. [Figure 4] 10 is a graph showing rail height levels over time. DETAILED DESCRIPTION OF THE INVENTION

[0015] The inventors investigated the causes of damage to bricks in unrepaired areas during coke oven re-laying repairs, in which multiple brick structures that make up multiple adjacent combustion chambers are simultaneously dismantled. As a result, it became clear that damage to bricks in unrepaired areas becomes more noticeable when four or more rows of adjacent combustion chambers are simultaneously dismantled, and moreover, becomes more noticeable when coal-loading cars pass over the dismantled areas.

[0016] Horizontal-chamber coke ovens have approximately 50 to 100 coke chambers and combustion chambers located between each coke chamber. The coke chambers and combustion chambers are arranged in an alternating, continuous array; this entire structure is called a furnace battery. Coke ovens also typically have one or two coal towers per furnace battery that store coal to be supplied to each coke chamber. Coal loading cars receive coal from these coal towers and travel on rails installed at the top of the coke oven, moving directly above each coke chamber. The coal is then loaded into the chamber through a loading hole in the ceiling of each coke chamber. Two rails are typically installed at the top of the coke oven, aligned in the direction of the alternating array of coke chambers and combustion chambers (toward the furnace battery). Multiple wheels are installed near each of the four corners of the loading car, supporting its weight and allowing it to travel on the rails.

[0017] When repairing the bricks that make up the combustion chamber of a coke oven, the bricks may be replaced in the center of one oven battery. In this case, there are unrepaired areas on both sides of the repaired area, and in many cases, the unrepaired areas continue to be heated and coke is produced while the repaired areas are being replaced.

[0018] When the brick structure that makes up the combustion chamber (hereafter referred to as the combustion chamber) is dismantled and removed, the rails installed above it lose the brick structure that supported them, so normally reinforcing girders are placed under and along the rails, and the weight of the coal cars is supported via supports on top of the ceiling bricks in the unrepaired area around the dismantled section. This state is shown diagrammatically in Figure 1.

[0019] In FIG. 1, the left-right direction is the arrangement direction (furnace cell direction), the up-down direction is called the furnace height direction, and the direction perpendicular to the drawing, which is perpendicular to these two directions, is called the furnace length direction. FIG. 1 is a vertical cross-sectional view of a coke oven, with alternating rows of coke chambers 1 and combustion chambers 2. In FIG. 1, the combustion chambers 2 are numbered No. 1 to No. 10, and the diagram shows the state in which combustion chambers No. 5 to No. 7 of these combustion chambers No. 1 to No. 10 have been removed. That is, the removed combustion chambers are indicated by dashed lines. Each combustion chamber extends in the furnace length direction. This invention targets a repair method in which all bricks aligned in the furnace length direction are replaced, but also targets a repair method in which some less deteriorated bricks in the combustion chamber to be repaired are not replaced or are reused. This invention is most effective when targeting a repair method in which all bricks in the combustion chamber are replaced.

[0020] In addition, below the bottom of the coking chamber 1 and the combustion chamber 2, there is a regenerator (not shown) made of a brick structure. Above the coking chamber 1 and the combustion chamber 2, there are ceiling bricks 3, with rails 4 placed on top of them. The load of the rails 4 is supported by supports 5 attached to some of the ceiling bricks 3. In a typical coke oven, the load of the rails 4 is supported by supports 5 attached to the ceiling of each combustion chamber via standard girders 6 installed below the rails 4. The ceiling bricks of the combustion chambers 5-7 dismantled here were also dismantled, leaving the rails 4 and standard girders 6 hanging in the air without support. Therefore, reinforcing girders 7 were added to those areas, or the standard girders 6 were replaced with reinforcing girders 7 with greater strength and rigidity, and the load was supported by multiple supports 5 in the unrepaired areas.

[0021] The inventors have found that, in the conventional repair method described above, as the removal of a larger portion of the combustion chamber increases, damage to the bricks of the combustion chambers located at the edge of the non-repaired portion becomes more likely. In other words, in the example of Figure 1, if the combustion chambers are dismantled over a wider area than that shown in Figure 1, for example, if four rows of combustion chambers No. 4 to No. 7 are removed, damage to the bricks of No. 3 and No. 8 at the edge of the non-repaired portion becomes more likely. The inventors have found that, when four or more adjacent rows of combustion chambers are removed, damage to the non-repaired portion increases.

[0022] After examining the reasons for this, it was determined that if the length of the removed section in the direction of the combustion chamber arrangement (towards the furnace battery) increases, all of the multiple wheels supporting the load near the four corners of the coal loading car spend a longer time on the suspended rail section, and the longer the length of the suspended rail section, the greater the moment generated by the load of the coal loading car. For example, if the removed section is the length of one row of combustion chambers, all of the multiple wheels supporting the load near the four corners of the coal loading car will not rest on the suspended rail section, making it easier for the unrepaired section to support the load of the coal loading car. However, if all of the coal loading car's wheels rest on the suspended rail section, the load may be concentrated at the end of the unrepaired section.

[0023] For example, in the coke oven where the method of the present invention was tested, the average width of the coking chambers in the direction of the oven battery was 435 mm, and the width of the combustion chambers was 960 mm, for a total of 1,395 mm. The coal loading cars used in this oven had three wheels on each of the front and rear sides of the track, and the distance between the ends of these three wheels in the direction of travel (toward the oven battery) was approximately 2,770 mm. Therefore, if multiple adjacent combustion chambers were removed and the length of the removed area in the oven battery direction increased, the time during which all three wheels of the loading car were simultaneously positioned above the open area would become significantly longer.

[0024] Based on these findings, the inventors investigated a method for preventing damage to bricks in unrepaired sections by installing supports for the rails in the remaining empty spaces after dismantling four or more rows of combustion chambers. As a result, they discovered that damage to bricks in unrepaired sections can be prevented by installing new supports for the rails in a location where the distance between the rail support position of the support and the center of the adjacent combustion chamber in the same arrangement direction is no more than four times the sum of the width of each combustion chamber in the arrangement direction and the width of each coking chamber in the arrangement direction (hereinafter referred to as the total width of the combustion chambers and coking chambers). This specification for the location of the supports is based on the case where three rows of combustion chambers are removed, in which damage to bricks in unrepaired sections is suppressed. In other words, it is based on the assumption that the distance between the centers of the unrepaired combustion chambers on both sides of the removed three rows (in the example shown in Figure 1, the distance between the centers of combustion chamber No. 4 and chamber No. 8) is four times the sum of the widths of each combustion chamber and each coking chamber. Thus, if the distance between the support pillar and the unrepaired combustion chamber is set to less than four times the sum of the width of each combustion chamber and the width of each carbonization chamber, past experience has shown that damage to the bricks in the unrepaired areas will not occur.

[0025] Here, when multiple supports are installed in the dismantled portion (space) of the combustion chamber, the distance between the supports does not need to be specified, as it does not affect damage to the bricks in the unrepaired portion. It is sufficient to install them in an appropriate position that can support the rails.

[0026] After installing the support pillars as described above, brickwork is carried out to construct a new combustion chamber in the dismantled combustion chamber. After the brickwork is replaced, the support pillars are removed and the combustion chambers are rebuilt one by one. Alternatively, the support pillars may be removed and the combustion chambers rebuilt one by one as long as either the distance between the center position of the combustion chamber in the unrepaired section and the support position where the nearest support pillar supports the rail (the center position in the arrangement direction of the top of the pillar that abuts the rail) is four times or less the total width of the combustion chamber and the coking chamber, or the distance between the centers of the combustion chambers in the unrepaired sections adjacent to the space is four times or less the total width of the combustion chamber and the coking chamber, is maintained. A typical example of construction in which supports are provided according to the above will be described with reference to FIG.

[0027] That is, Figure 2 shows an example in which, in the same coke oven as Figure 1, six rows of combustion chambers No. 2 to No. 7 have been removed, and supports 8 supporting rails 4 have been installed at positions No. 2, No. 3, and No. 4. The positions where the supports 8 support the rails 4 are the same as the central positions (in the arrangement direction) of each of the removed combustion chambers. Here, the distance between the support at the center position of combustion chamber No. 4 and the center of combustion chamber No. 8 is four times the sum of the widths of each combustion chamber and each coke chamber. Also, the distance between the support at position No. 2 and the center of combustion chamber No. 1 is one time the sum of the widths of each combustion chamber and each coke chamber.

[0028] In the example of Figure 2, three support pillars 8 are installed, but it is also possible to install only one support pillar at position No. 4. In that case, the distance between the support pillar at position No. 4 and the center of No. 1 combustion chamber is three times the sum of the width of each combustion chamber and the width of each coking chamber, which prevents damage to the bricks in the unrepaired areas.

[0029] Next, a schematic diagram of an example of a support column 8 is shown in Figure 3. Figure 3(a) is a side view of the support column 8 from the furnace length direction, and Figure 3(b) is a side view of the support column 8 from the arrangement (furnace battery) direction. Each support column 8 is structured to support one rail 4. That is, as shown in Figure 3, the support column 8 is structured such that the jack section 8a is installed on two sets of support legs 9a, 9b, a pedestal support section 10 is installed on the jack section 8a, and a pedestal 5 is installed on the pedestal support section 10, and the pedestal 5 supports the reinforcing girder 7.

[0030] Each of the support legs 9a, 9b has a support leg base member 20 at its bottom, a support column member 21, and an upper support member 22, and the support column members are connected to each other by a first connecting member 23, and the two sets of support legs 9a, 9b are connected to each other by a second connecting member 24. These members can be made of steel or thick plates, and can be connected by welding, bolting, or the like.

[0031] The jack section 8a is provided with a jack 30 that is extendable in the vertical direction and a third connecting member 25 that is adjustable in length in the vertical direction. If adjustment of the height of the support column 8 is not required, the jack section 8a does not have to be provided, and the jack 30 does not have to be provided, and the third connecting member 25 does not have to have a length adjustment function.

[0032] The height positions of the cradle support part 10 and the cradle 5 provided on the jack part 8a can be adjusted by using jacks 30 installed on the support legs 9a and 9b, respectively. The cradle 5 installed on the cradle support part 10 is installed so as to span between the two cradle support parts 10 installed on the two support legs 9a and 9b, respectively, and the cradle 5 supports the rail 4 via the reinforcing girder 7. A fourth connecting member 26 may be provided to connect the two cradle support parts 10.

[0033] The two pillars 8 supporting the two rails 4 may be positioned in the same direction (furnace battery) or in different directions. In this case, the distance between the support position where the pillars 8 support the rails 4 and the center position of the combustion chamber at the end of the unrepaired section, at the widest point, should be no more than four times the sum of the width of each combustion chamber and the width of each coking chamber.

[0034] Since the support pillars 8 are installed on the bricks that form the bottom of the coke chamber 1 or the combustion chamber 2, it is preferable to prevent the load of the support pillars 8 from concentrating on a specific position on the hearth bottom bricks. To achieve this, it is preferable to distribute the load by, for example, placing an iron plate or the like under the support pillars 8.

[0035] As shown in Figure 2, when the pillars 8 are installed adjacent to each other in the direction of the arrangement (furnace battery), steel material can be placed between the pillars and welded to secure them, which will prevent the pillars 8 from tilting in the direction of the arrangement (furnace battery), thereby more reliably supporting the rails 4.

[0036] Furthermore, if a jack section 8a is provided on part of the support pillar 8 so that the height of the top of the support pillar can be adjusted, when installing the support pillar 8, the height of the support pillar 8 can be lowered and the support pillar 8 can be installed under the rail 4, and the top of the support pillar 8 can be jacked up with the jack section 8a to support the rail 4, making installation of the support pillar 8 easier.

[0037] Furthermore, if a jack capable of adjusting the height of the top of the pillar 8 supporting the rail 4 is installed on the pillar 8, it will be possible to adjust the height of the pillar 8 even after installation. For example, by adjusting the height of the top of the pillar 8 so that the difference between the height of the coal car rail 4 at the part supported by the pillar and the height of the rail 4 at the end of the unrepaired part is within ±5 mm, it is possible to reduce the concentration of load on the combustion chamber bricks and more effectively prevent damage to the bricks in the unrepaired part.

[0038] Furthermore, a load measuring device (not shown) can be installed between the support base 5 at the top of the support pillar 8 and the reinforcing girder 7, or between the reinforcing girder 7 at the installation position of the support pillar 8 and the coal car rail 4, or between the rail 4 in the combustion chamber at the end of the unrepaired section and the regular girder 6 (or reinforcing girder 7) supporting the rail, or between the regular girder 6 (or reinforcing girder 7) and the support base 5, and the height of the top of the support pillar 8 can be adjusted so that the stress on the part that the support pillar 8 is subjected to is close to the stress on the unrepaired section. For example, it is preferable to adjust the height of the top of the support pillar so that the difference between the maximum stress on the support pillar 8 and the maximum stress on the unrepaired section when a coal car is passing, or the difference in the average stress between the two when a coal car is not passing, is within ±5%.

[0039] The method for measuring the maximum stress in the support pillar 8 is not particularly limited, but a strain gauge may be attached to the support pillar 8, and the maximum stress measured by the strain gauge when the coke oven is in operation may be measured. The maximum stress in the support pillar 8 is measured when a coal car passes over the rail 4 directly above the support pillar 8. Meanwhile, the maximum stress in the unrepaired portion can also be measured in the same way. [Example]

[0040] In the coke oven shown in Figure 2, when the bricks of six consecutive rows of combustion chambers No. 2 to No. 7 were dismantled and replaced for repair, pillars 8 were installed in the dismantled areas. That is, after dismantling combustion chambers No. 2 to No. 7, three pillars 8 per rail were installed on each of the two coal car rails 4 at the positions shown in Figure 2, and steel members (reinforcing girders 7) were placed between the pillars supporting the same rail in the direction of the arrangement (furnace battery) and welded to connect them.

[0041] In this state, the combustion chambers in the area where support pillars 8 were not installed (locations No. 5-7 in Figure 2) were reloaded while the unrepaired coke ovens on both sides of the demolished section continued to operate. In this state, the distance between support pillar 8 installed at location No. 4 adjacent to the removed section and the edge of the unrepaired section (location No. 8) was four times the sum of the widths of the individual combustion chambers and the individual coking chambers. To operate the unrepaired section, coal-loading cars made approximately 20-30 round trips per day on the rails above the repaired section. After completing the reloading of the combustion chambers in the area where support pillars were not installed (locations No. 5-7 in Figure 2), support pillar 8 was removed, and the combustion chambers in the area where support pillars 8 were installed (locations No. 2-4 in Figure 2) were reloaded. In this state, the distance between the combustion chambers adjacent to the removed section (locations No. 1 and No. 5) was four times the sum of the widths of the individual combustion chambers and the individual coking chambers.

[0042] During the above-mentioned re-laying period, no damage occurred to the bricks in the repaired and unrepaired areas. Therefore, it became clear that damage to the bricks in the unrepaired areas could be prevented by using supports and keeping the distance between the supports and the unrepaired areas, or between the repaired and unrepaired areas, to no more than four times the combined width of the combustion chamber and the coking chamber.

[0043] Next, when the coke oven continued operating in the unrepaired sections with the support pillars 8 installed (as shown in Figure 2), the rail height level at the support portion of each pillar and the rail height level at the unrepaired sections were measured using a laser rangefinder. The measurement results are shown in Figure 4, which plots the difference between the rail height level at the support portion of each pillar and the rail height level at the unrepaired sections as a function of the number of days since the installation of the support pillars 8. The difference in height level is shown for each pillar. As shown in Figure 4, the difference in height was within ±5 mm. It was clear that damage to the bricks in the unrepaired sections could be reliably prevented by using support pillars to maintain the rail level within ±5 mm of the rail level at the unrepaired sections. Figure 4 also shows a slight tendency for the difference in level to increase as the number of days increases. Therefore, it is preferable to adjust the rail height level at the support pillars using a jack or other tool to keep the difference in level within ±5 mm. On the other hand, since the rail height level does not change suddenly, it can be seen that adjustment of the rail height level is not necessary for a short period of time.

[0044] In addition, the stress exerted by the rails when coal-loading cars passed over the duration of the coke oven operation was measured at the No. 4 support and the unrepaired section at No. 8. The maximum stress was 2.4 kgf / mm 2 and 2.3 kgf / mm for unrepaired areas. 2 The difference in stress between the support and unrepaired sections was within 5%. It became clear that damage to bricks in the unrepaired sections could be more reliably prevented by using supports to limit the maximum stress received from the rails in the support sections to ±5% of that in the unrepaired sections.

[0045] As described above, when repairing a coke oven by simultaneously dismantling and re-installing four or more adjacent rows of combustion chambers, if supports are installed in the dismantling section and the re-installation is carried out so that the distance between the supports and the combustion chambers does not exceed a specified value, damage to bricks in the non-repaired section can be prevented and the re-installation repair can be carried out even under conditions where coal loading cars pass over the top of the dismantling section. [Explanation of symbols]

[0046] 1 carbonization chamber 2. Combustion chamber 3 Ceiling bricks 4 Rails 5 Receiving stand 6 normal digits 7 Reinforcement girder 8 pillars 9a, 9b Support legs 10 Cradle support part 20 Support leg base member 21 Support column member 22 Upper support member 23 First connecting member 24 second connecting member 25 Third connecting member 26 Fourth connecting member 30 Jack

Claims

1. A method for repairing a coke oven having a plurality of combustion chambers and carbonization chambers arranged alternately, the method comprising removing constituent bricks of a brick structure constituting the combustion chambers and replacing them with new constituent bricks, After removing the bricks constituting four or more adjacent rows of the combustion chambers among the combustion chambers, for each of two combustion chambers adjacent to the space created by removing the bricks, a support for supporting a coal car rail installed at the top of the coke oven is installed at a position where the distance from the center of the combustion chamber in the arrangement direction is four times or less the sum of the width of each of the combustion chambers in the arrangement direction and the width of each of the carbonization chambers in the arrangement direction, Next, a brick structure is reconstructed in the space using new bricks. How to repair a coke oven.

2. A method for repairing a coke oven as described in claim 1, wherein the height of the top of the pillar is adjusted so that the difference between the height of the coal car rail at the position supported by the pillar and the height of the coal car rail at the end of the non-repaired section adjacent to the space section in the arrangement direction is ±5 mm or less.

3. adjusting the height of the top of the pillar so that the difference in maximum stress between the pillar and the unrepaired portion when a coal car passes over the coal car rail is within ±5%; The method for repairing a coke oven according to claim 2.

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