Method for judging the timing of replacing bottom bricks of coke oven

Abstract

To provide a judging method by which the time for reloading furnace bottom bricks in a carbonization chamber can properly be found out in relation to the actually occurring pushing clogging.SOLUTION: The determination method includes a push-out step, a detection step, an accumulation step, a cleaning step, a measurement step, a determination step, an identification step, a collation step, and a determination step (steps #5 to #45). In the final determination step (step #45), when a specific portion is present in the displacement of the furnace bottom of the carbonizing chamber in which the push-clogging has occurred, and the position x1 at which the maximum displacement of the specific portion appears overlaps the position x2 at which the second peak appears in the immediately preceding pushing force waveform, it is determined that the time to restack the bricks on the furnace bottom in the carbonizing chamber has arrived.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a method for determining when to replace hearth bricks in a coke oven, the method determining when to replace hearth bricks in a coking chamber of the coke oven. [Background technology]

[0002] Coke ovens are used to produce coke, one of the raw materials used in steelmaking. Generally, a coke oven is composed of multiple coke chambers and multiple combustion chambers. The coke chambers are arranged alternately with the combustion chambers, and the coke chambers and combustion chambers are separated by a furnace wall made of bricks. In the horizontal plane of a coke oven, the direction in which the coke chambers and combustion chambers are arranged is called the furnace cell direction, and the direction perpendicular to the furnace cell direction, i.e., the direction in which the coke chambers and combustion chambers extend, is called the furnace length direction. In the coke chamber, coal is carbonized by heat from the combustion chamber to form coke. The coke chamber is sometimes called a kiln because it is the place where the object to be manufactured, i.e., coke, is produced and stored.

[0003] The coke produced in the carbonization chamber is pushed out of the carbonization chamber in the furnace length direction by an extruder. Specifically, the extruder is equipped with a ram head, which is inserted into the carbonization chamber from one of the chamber openings (the extruder-side opening) and moves through the carbonization chamber in the furnace length direction toward the other opening (the guide car-side opening). During the extrusion operation, the coke in the carbonization chamber is pushed by the ram head moving through the carbonization chamber and discharged from the carbonization chamber.

[0004] Coke ovens are equipment that are used continuously over long periods of time, and in some cases they have been in use for nearly 50 years since construction. In such cases, various problems are likely to occur due to deterioration over time. A typical problem that occurs in coke ovens due to deterioration over time is clogging. Clogging occurs when excessive pushing force is generated during the extrusion operation, causing the extruder to make an emergency stop and making it impossible to extrude the coke midway. When clogging occurs, the extrusion operation must be stopped and the coke remaining in the carbonization chamber must be removed manually. This reduces coke productivity.

[0005] It is generally believed that one of the causes of clogging is fine coke leaking into the gap between the ram head and the oven wall as the ram head moves through the coke chamber. The fine coke leaking into the gap between the ram head and the oven wall creates physical resistance, increasing the pushing force of the ram head. If this pushing force exceeds the extruder's tolerance, the extruder will make an emergency stop and the ram head will stop. To prevent fine coke leakage, the gap between the ram head and the oven wall can be properly managed. However, as the extrusion operation is repeated, the oven wall is gradually worn down and damaged by friction with the coke. As a result, the gap between the ram head and the oven wall widens, increasing the leakage of fine coke. When the damage to the oven wall becomes excessive, the damaged area is repaired.

[0006] The hearth of the coke oven is also made of bricks, just like the oven walls, and as the extrusion operation is repeated, it is gradually worn down and damaged by friction with the coke. The hearth directly bears the weight of the coke and is therefore more susceptible to damage than the oven walls. A damaged hearth resists friction with the coke, significantly increasing the extrusion force of the ram head. In short, as the hearth, not only the oven walls but also the hearth, deteriorates over time, it becomes prone to clogging. When damage to the hearth becomes excessive, the damaged area is repaired and, in some cases, bricks are replaced.

[0007] Techniques for measuring the shape of the hearth when repairing the hearth of a coking chamber are described, for example, in Japanese Patent Application Laid-Open No. 2009-068765 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2022-134406 (Patent Document 2). In the technique of Patent Document 1, a 3D camera is used to capture multiple images of the same coking chamber at different angles, and the profile of the refractory material including the hearth is calculated from the image data. In the technique of Patent Document 2, a laser-type three-dimensional shape measuring device irradiates the coking chamber with a laser, and the shape of the furnace body including the hearth is obtained as a point cloud. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-068765 [Patent Document 2] Japanese Patent Publication No. 2022-134406 Summary of the Invention [Problem to be solved by the invention]

[0009] According to the techniques of Patent Documents 1 and 2, the shape of the hearth of the coke chamber can be measured. Therefore, by using the techniques of Patent Documents 1 and 2, it is possible to determine to a certain extent the time to repair the hearth of the coke chamber. However, since the techniques of Patent Documents 1 and 2 simply measure the shape of the hearth of the coke chamber, it cannot be said that they can appropriately determine the time to replace the hearth bricks of the coke chamber in relation to the clogging that actually occurs.

[0010] The object of the present disclosure is to provide a method for determining the timing for replacing hearth bricks in a coke oven, which can appropriately determine the timing for replacing hearth bricks in a coking chamber in relation to clogging that actually occurs. [Means for solving the problem]

[0011] The method for determining when to replace hearth bricks in a coke oven according to the present disclosure is a method for determining when to replace hearth bricks in a coking chamber of a coke oven, and includes a pushing step, a detecting step, a accumulating step, a cleaning step, a measuring step, a determining step, a specifying step, a comparing step, and a determining step.

[0012] The pushing process involves carrying out a coke pushing operation using a ram head moving in the furnace length direction within the coking chamber. The detection process involves detecting the pushing force of the ram head as it moves within the coking chamber and passes through each position in the furnace length direction of the coking chamber during the pushing operation. The accumulation process involves accumulating a pushing force waveform for the pushing force detected in the detection process. The pushing force waveform represents the progression of the pushing force associated with each position in the furnace length direction of the coking chamber, and includes at least a first peak near the start of the pushing operation. The cleaning process involves stopping the pushing operation and cleaning the coking chamber when clogging occurs during the pushing operation. The measurement process involves measuring the heightwise displacement of the hearth along the furnace length direction of the coking chamber after the cleaning process. The determination process involves determining whether or not there is a unique portion in the hearth having a displacement exceeding a predetermined range based on the results of the measurement process.

[0013] If the result of the determination step indicates that a peculiar portion exists, the identification step identifies a position x1 in the furnace length direction of the coking chamber at the hearth measured in the measurement step where the maximum displacement of the peculiar portion appears. Furthermore, the identification step identifies a second peak, which is the maximum peak among one or more peaks that appear after the first peak, in the pushing force waveform accumulated in the accumulation step, and a position x2 in the furnace length direction of the coking chamber at which the second peak appears. The comparison step compares position x1 with position x2 and determines whether position x1 overlaps with position x2. If the result of the comparison step indicates that position x1 overlaps with position x2, the determination step determines that it is time to replace the bricks in the hearth of the coking chamber. [Effects of the Invention]

[0014] According to the determination method of the present disclosure, it is possible to appropriately determine the timing for replacing hearth bricks in the coking chamber in relation to the clogging that actually occurs. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing an example of displacement of the hearth in the height direction in the coking chamber. [Figure 2] FIG. 2 is a diagram showing an example of a push-out force waveform. [Figure 3]FIG. 3 is a schematic diagram showing the overall configuration of a coke oven. [Figure 4] FIG. 4 is a side view of the extruder. [Figure 5] FIG. 5 is a flow chart showing a method for determining the timing of replacing hearth bricks of a coke oven according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] In order to solve the above problems, the present inventors have conducted extensive research and as a result have made the following findings.

[0017] In actual coke ovens, there are multiple coke chambers that are prohibited from use and are in an out-of-operation state. In this specification, such coke chambers are also referred to as out-of-operation coke chambers. The out-of-operation coke chambers were those that required some kind of repair due to frequent clogging. The present inventors have considered reusing such out-of-operation coke chambers.

[0018] The inventors first measured the displacement of the furnace walls and hearth of the non-operating coking chamber along the furnace length. As a result of the measurements, no areas with excessive displacement were found on the furnace walls. However, unusual convex or concave areas with excessive displacement were found on the hearth. Furthermore, the hearth bricks of the non-operating coking chamber were replaced for reuse, and the displacement of the hearth was then measured along the furnace length. A laser-type three-dimensional shape measurement device was used for the measurements.

[0019] Fig. 1 is a diagram showing an example of the displacement of the hearth in the height direction in the coking chamber. In Fig. 1, the displacement before brick replacement is shown by a thin line, and the displacement after brick replacement is shown by a thick line. In Fig. 1, the horizontal axis represents the distance from the extruder-side kiln opening in the furnace length direction, and the vertical axis represents the displacement of the hearth in the height direction, with the height of the extruder-side kiln opening as the reference (zero).

[0020] As shown by the thick line in Figure 1, the displacement of the hearth after brick replacement was small and stable. On the other hand, as shown by the thin line in Figure 1, in the hearth before brick replacement, a convex peculiar part with excessive displacement existed in the range from approximately 12 m to 15 m. In other words, since the furnace length in the coking chamber (the length from the kiln opening on the extruder side to the kiln opening on the guide car side) is approximately 16 m, the peculiar part was located near the kiln opening on the guide car side, not on the kiln opening on the extruder side. Of the various positions in the coking chamber along the furnace length, position x1, where the maximum displacement of the peculiar part appeared, was approximately 14 m.

[0021] Here, typically, to mainly monitor for signs of clogging, the pushing force of the ram head of the extruder moving within the coking chamber is detected when the ram head passes through each position in the furnace length direction of the coking chamber during the extrusion operation. The pushing force corresponds to the reaction force that the ram head receives from the coke, i.e., the torque of the motor that drives the ram head. Then, a pushing force waveform based on each pushing force is accumulated. The pushing force waveform represents the progression of the pushing force associated with each position in the furnace length direction of the coking chamber. In other words, the pushing force waveform represents the change in the pushing force along the furnace length direction of the coking chamber.

[0022] Therefore, the inventors investigated the most recent extrusion operation results of the non-operating coking chamber in order to confirm the relationship between the properties of the hearth of the non-operating coking chamber and clogging. Specifically, the inventors investigated the extrusion force waveform accumulated during the most recent extrusion operation using the non-operating coking chamber. Furthermore, the hearth bricks of the non-operating coking chamber were replaced for reuse, and an extrusion operation was carried out using the coking chamber, and the extrusion force waveform accumulated during the extrusion operation was investigated.

[0023] Fig. 2 is a diagram showing an example of an extrusion force waveform. Fig. 2 shows the extrusion force waveform before the hearth bricks are replaced and the extrusion force waveform after the hearth bricks are replaced (the first and second extrusion force waveforms after the replacement). In Fig. 2, the extrusion force waveform before the replacement is shown by a thin line, and the first and second extrusion force waveforms after the replacement are shown by a solid line and a dotted line, respectively. In Fig. 2, the horizontal axis represents the position of the ram head in the furnace length direction, with the position of the extruder-side kiln opening as the reference (zero), and corresponds to the distance from the extruder-side kiln opening in the furnace length direction shown in Fig. 1. In Fig. 2, the vertical axis represents the extrusion force.

[0024] As shown by the solid and dotted lines in Figure 2, when the carbonization chamber after hearth brick replacement was used, the extrusion force waveform contained a first peak near the kiln mouth on the extruder side, i.e., near the start of the extrusion operation. As shown below, the first peak always appears near the start of the extrusion operation.

[0025] During the pushing operation, the coke in the coke chamber is pushed out of the chamber by the ram head moving within the chamber. First, when the ram head starts to push the coke, it is crushed by the ram head and the entire coke is compressed. At this time, static friction acts between the coke and the furnace inner surface (furnace wall and furnace bottom), and the coke remains stationary. Then, as the ram head moves, the pushing force increases against the static friction force, and when the friction force between the coke and the furnace inner surface reaches the maximum static friction force, the entire coke begins to move. Once the entire coke begins to move, the coke is subjected to a kinetic friction force that is smaller than the maximum static friction force. Therefore, the pushing force reaches its maximum value and then rapidly decreases. This maximum value of the pushing force is the first peak.

[0026] In the extrusion force waveform when using the coking chamber after replacing the hearth bricks, the position where the first peak appeared among the various positions in the furnace length direction of the coking chamber was generally within the range of 1.5 m to 2 m. In other words, the position of the first peak in the extrusion force waveform was close to the kiln opening on the extruder side, that is, close to the start of extrusion operation.

[0027] In the pushing force waveform, the pushing force gradually decreased after the first peak. This was due to the following reason: After the first peak, coke was successively discharged from the coke chamber as the ram head moved. As a result, the amount of coke in the coke chamber gradually decreased, and the pushing force required for the ram head to push the coke gradually decreased. Thus, the pushing force waveform when using the coke chamber after hearth brick replacement did not include any other peaks other than the first peak. In this case, the pushing operation was carried out smoothly, and no clogging occurred.

[0028] On the other hand, as shown by the thin line in Figure 2, in the extrusion operation results when using a non-operating carbonization chamber before the hearth bricks were replaced, the first peak appeared in the extrusion force waveform, which was the same as when using a carbonization chamber after the hearth bricks were replaced.

[0029] However, in the pushing force waveform when the non-operating coking chamber was used, the pushing force did not tend to gradually decrease after the first peak, but rather increased and decreased. That is, the pushing force waveform in this case included one or more peaks after the first peak. In this pushing force waveform, the maximum peak among the one or more peaks that appeared after the first peak was defined as the second peak. In this pushing force waveform, among the positions in the furnace length direction of the coking chamber, position x2 where the second peak appeared was approximately 14 m. Therefore, position x2 where the second peak appeared overlapped with position x1 where the maximum displacement of the anomalous part appeared. In other words, position x1 where the maximum displacement of the anomalous part appeared overlapped with position x2 where the second peak appeared.

[0030] Based on the above facts, if there is a unique part in the displacement of the hearth of the coking chamber where clogging has occurred, and the position x1 where the maximum displacement of that unique part appears overlaps with the position x2 where the second peak appeared in the immediately preceding pushing force waveform, it can be confirmed that the clogging has occurred due to the unique part. Therefore, if it is determined that the time has come to replace the hearth bricks in the coking chamber when position x1 overlaps with position x2, it can be said that the time to replace the hearth bricks in the coking chamber can be appropriately determined in relation to the clogging that actually occurs.

[0031] The method for determining the timing of hearth brick replacement for a coke oven according to an embodiment of the present disclosure has been completed based on the above findings.

[0032] A method for determining when to replace hearth bricks in a coke oven according to an embodiment of the present disclosure is a method for determining when to replace hearth bricks in a coking chamber of a coke oven, and includes a pushing step, a detecting step, a accumulating step, a cleaning step, a measuring step, a determining step, a specifying step, a comparing step, and a determining step.

[0033] The pushing process involves carrying out a coke pushing operation using a ram head moving in the furnace length direction within the coking chamber. The detection process involves detecting the pushing force of the ram head as it moves within the coking chamber and passes through each position in the furnace length direction of the coking chamber during the pushing operation. The accumulation process involves accumulating a pushing force waveform for the pushing force detected in the detection process. The pushing force waveform represents the progression of the pushing force associated with each position in the furnace length direction of the coking chamber, and includes at least a first peak near the start of the pushing operation. The cleaning process involves stopping the pushing operation and cleaning the coking chamber when clogging occurs during the pushing operation. The measurement process involves measuring the heightwise displacement of the hearth along the furnace length direction of the coking chamber after the cleaning process. The determination process involves determining whether or not there is a unique portion in the hearth having a displacement exceeding a predetermined range based on the results of the measurement process.

[0034] If the result of the determination step indicates that a peculiar portion exists, the identification step identifies a position x1 in the furnace length direction of the coking chamber at the hearth measured in the measurement step where the maximum displacement of the peculiar portion appears. Furthermore, the identification step identifies a second peak, which is the maximum peak among one or more peaks that appear after the first peak, in the pushing force waveform accumulated in the accumulation step, and a position x2 in the furnace length direction of the coking chamber at which the second peak appears. The comparison step compares the position x1 with the position x2 and determines whether the position x1 overlaps with the position x2. If the result of the comparison step indicates that the position x1 overlaps with the position x2, the determination step determines that it is time to replace the bricks in the hearth of the coking chamber (first configuration).

[0035] The determination method according to the first configuration includes a series of steps, including a pushing step, a detecting step, a accumulating step, a cleaning step, a measuring step, a determining step, a identifying step, a comparing step, and a determining step, and ultimately determines that it is time to replace the hearth bricks in the coking chamber. To make this final determination, the vertical displacement of the hearth of the coking chamber where the clogging actually occurred and the pushing force waveform during the pushing operation performed immediately before the clogging occurred are used. As described above, if there is a unique portion in the displacement of the hearth of the coking chamber where the clogging occurred, and if the position x1 where the maximum displacement of the unique portion appears overlaps with the position x2 where the second peak appeared in the immediately preceding pushing force waveform, it can be confirmed that the clogging occurred due to the unique portion. According to the determination method according to the first configuration, if the position x1 overlaps with the position x2, it is determined that it is time to replace the hearth bricks in the coking chamber. Therefore, it is possible to appropriately determine the time to replace the hearth bricks in the coking chamber in relation to the actual clogging.

[0036] In practice, the above determination method is preferably configured as follows: In the determination step, the predetermined range is from -30 mm to 30 mm. In the comparison step and determination step, if the absolute value of the difference between position x1 and position x2 is 100 mm or less, position x1 is deemed to overlap with position x2 (second configuration).

[0037] In practice, the above-mentioned determination method is preferably configured as follows: In the measurement step, the displacement of the hearth is measured using a laser type three-dimensional shape measuring device (third configuration).

[0038] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components are designated by the same reference numerals, and redundant description will not be repeated.

[0039] [Coke oven] Fig. 3 is a schematic diagram showing the overall configuration of a coke oven 100. Fig. 3 shows the coke oven 100 as viewed along the direction of the oven battery. In particular, Fig. 3 shows a vertical cross-sectional view of a coke chamber 1.

[0040] Referring to Figure 3, the coke oven 100 includes a number of coking chambers 1 and a number of combustion chambers (not shown). The coking chambers 1 are arranged alternately with the combustion chambers in the direction of the oven battery, and the coking chambers 1 and the combustion chambers are separated by oven walls (not shown). That is, in Figure 3, the oven walls of the coking chambers 1 are arranged at the front and back, respectively. The coking chamber 1 is defined by these oven walls, a hearth 11, and a ceiling 12. As a result, when the coking chamber 1 is viewed along the oven length direction, the shape of the inner furnace surface of the coking chamber 1 is substantially rectangular. A coal loading port 13 is formed in the ceiling 12. The oven walls, ceiling 12, and hearth 11 are made of bricks.

[0041] The carbonization chamber 1 has an extruder-side kiln opening 14 at one end in the furnace length direction, and a guide car-side kiln opening 15 at the other end in the furnace length direction. An extruder 2 is arranged outside the extruder-side kiln opening 14, and a guide car (not shown) and a fire extinguishing car 3 are arranged outside the guide car-side kiln opening 15. The extruder 2, guide car, and fire extinguishing car 3 are all arranged so that they can move in the direction of the kiln battery.

[0042] In the coke oven 100, combustion gas is burned in the combustion chamber, and the heat in the combustion chamber is supplied to the coke chamber 1 mainly by thermal conduction through the oven wall. Coal, which is the raw material for coke, is charged into the coke chamber 1 through a coal charging port 13, which is then closed with a lid (not shown). The coal in the coke chamber 1 is carbonized by the heat from the combustion chamber to form coke.

[0043] The coke produced in the carbonization chamber 1 is pushed out of the carbonization chamber 1 by the pusher 2. Specifically, when the extrusion operation is carried out, the extruder 2 is on standby near the extruder-side kiln opening 14, and the guide car and fire extinguishing car 3 are on standby near the guide car-side kiln opening 15. Furthermore, the door (not shown) of the extruder-side kiln opening 14 opens, and the door (not shown) of the guide car-side kiln opening 15 opens. This opens the extruder-side kiln opening 14 and the guide car-side kiln opening 15.

[0044] The extruder 2 is equipped with a ram head 21, which is inserted into the carbonization chamber 1 from the extruder-side kiln port 14 and moves within the carbonization chamber 1 in the furnace length direction toward the guide car-side kiln port 15. The coke in the carbonization chamber 1 is pushed by the ram head 21 moving within the carbonization chamber 1 and discharged from the carbonization chamber 1 through the guide car-side kiln port 15. The discharged coke is guided by the guide car to the fire extinguisher car 3 and extinguished (cooled) by the fire extinguisher car 3. In short, during the extrusion operation, the ram head 21 comes into contact with and pushes the coke in the carbonization chamber 1, and the coke pushed by the ram head 21 is discharged one after another through the guide car-side kiln port 15.

[0045] [Extruder] Figure 4 is a side view of the extruder 2. Figure 4 shows a portion of the extruder 2 as viewed along the furnace battery direction. Referring to Figure 4, the extruder 2 includes a ram head 21, a ram beam 22, a slide shoe 23, and a motor 24. The ram beam 22 is an elongated member that extends in the furnace length direction and is longer than the length of the coking chamber 1. The ram beam 22 is arranged so that it can move forward or backward in the furnace length direction. The ram head 21 is fixed to the tip of this ram beam 22. The ram head 21 is a roughly plate-shaped member. When the ram head 21 is viewed along the furnace length direction, the outline shape of the ram head 21 is substantially rectangular and slightly smaller than the shape of the inner furnace surface of the coking chamber 1.

[0046] The slide shoe 23 is disposed below the ram beam 22 and is integrated with the ram beam 22. The slide shoe 23 supports the long ram beam 22 and, in its basic design, serves to prevent the ram head 21 from coming into contact with the hearth bottom 11. Typically, the slide shoe 23 is disposed behind the ram head 21 near the tip of the ram beam 22.

[0047] The motor 24 is a drive source that provides force to move the ram beam 22 in the furnace length direction. A rack gear 25 is provided on the upper surface of the ram beam 22. The rack gear 25 is formed in the furnace length direction. A pinion gear 26 is connected to the motor 24 via a reducer 27. The pinion gear 26 is arranged to mesh with the rack gear 25 of the ram beam 22, and rotates by the driving force of the motor 24. The pinion gear 26 rotates while meshing with the rack gear 25, causing the ram beam 22 to move in the furnace length direction. This causes the ram head 21 to move in the furnace length direction within the coking chamber 1.

[0048] [Method for determining when to replace hearth bricks in a coke oven] The determination method according to this embodiment is a method for determining when to replace the hearth bricks 11 in the coking chamber 1 that constitutes the coke oven 100. FIG. 5 is a flow chart showing the method for determining when to replace the hearth bricks of the coke oven 100 according to this embodiment. Referring to FIG. 5, the determination method according to this embodiment includes a pushing process (step #5), a detecting process (step #5), an accumulating process (step #5), a cleaning process (step #15), a measuring process (step #20), a determining process (step #25), an identifying process (step #30), a comparing process (step #40), and a determining process (step #45). Specific details of each process (steps #5 to #45) will be described below.

[0049] In step #5, the pushing process, detection process, and accumulation process are performed. Specifically, in the pushing process, the coke is pushed out by the ram head 21, which moves in the furnace length direction within the coke chamber 1. As described above, during the pushing operation, as the ram head 21 moves within the coke chamber 1, the ram head 21 comes into contact with the coke and pushes it. The coke pushed by the ram head 21 is successively discharged from the coke chamber 1 through the guide car side kiln opening 15.

[0050] The detection process detects the pushing force of the ram head 21 when the ram head 21 moving within the coking chamber 1 passes through each position in the furnace length direction of the coking chamber 1 during the extrusion operation. The pushing force corresponds to the torque of the motor 24 of the extruder 2. The position of the ram head 21 within the coking chamber 1 can be detected by detecting the rotation angle of the motor 24. The pushing force corresponding to each position of the ram head 21 can be detected by measuring the torque of the motor 24. Information regarding each position of the ram head 21 and the pushing force corresponding to each position is stored and accumulated in a storage device (not shown) each time.

[0051] The accumulation process accumulates an extrusion force waveform for the extrusion force detected in the detection process. The extrusion waveform is, for example, an extrusion force waveform as shown in FIG. 2 above. The extrusion force waveform represents the progression of the extrusion force associated with each position in the furnace length direction of the coking chamber 1. The extrusion force waveform includes at least a first peak at a position close to the start of the extrusion operation. The extrusion force waveform is based on information regarding each position of the ram head 21 and the extrusion force corresponding to each position, and is essentially accumulated in the storage device by the detection process.

[0052] Here, in step #10, the case is classified based on whether clogging occurred during the extrusion operation. If clogging did not occur, that is, if the extrusion operation was completed normally, the process returns to step #5, and the next coke is produced using the coke chamber 1, and the extrusion operation is carried out. On the other hand, if clogging occurred, the process proceeds to step #15.

[0053] In step #15, a cleaning process is performed. Specifically, in the cleaning process, when a jam occurs during the extrusion operation, the extrusion operation is stopped and the inside of the coking chamber 1 is cleaned. In this case, the jam occurs and the ram head 21 stops inside the coking chamber 1, so the normal extrusion operation is stopped. With the extrusion operation stopped, the ram head 21 is moved backward and removed from the coking chamber 1. Then, the coke remaining in the coking chamber 1 is manually removed. In this way, in the cleaning process, the inside of the coking chamber 1 is cleaned. Note that in the cleaning process, the output of the motor 24 may be intentionally increased to move the ram head 21 forward, thereby discharging the coke in the coking chamber 1 from the coking chamber 1.

[0054] Next, in step #20, a measurement process is performed. Specifically, in the measurement process, after the cleaning process, the height displacement of the hearth 11 along the furnace length direction of the coking chamber 1 is measured. A well-known laser-type three-dimensional shape measuring device can be used for the measurement. This makes it possible to obtain the height displacement of the hearth 11 in the coking chamber 1. This displacement is, for example, as shown in Figure 1 above.

[0055] Next, in step #25, a determination step is performed. Specifically, the determination step determines whether or not there is a peculiar part in the hearth 11 with a displacement exceeding a predetermined range based on the results of the measurement step. If there is a peculiar part, proceed to step #30. On the other hand, if there is no peculiar part, proceed to step #35. Here, the predetermined range that serves as the criterion for determining a peculiar part can be a range from -30 mm to +30 mm. In this case, a peculiar part is a part of the hearth 11 with a displacement exceeding 30 mm. In a typical example, a peculiar part is a convex part where the sign of the displacement is positive. A convex peculiar part is formed, for example, by repeated replenishment of repair material or adhesion of coke. A peculiar part may also be a concave part where the sign of the displacement is negative. A concave peculiar part is formed, for example, by damage to the hearth 11. In the example of displacement shown by the thin line in Figure 1 above, the peculiar part is a convex part, and among the positions in the furnace length direction of the coking chamber 1, the position x1 where the maximum displacement of the peculiar part appeared is approximately 14 m.

[0056] If the process proceeds to step #35, that is, if the result of the judgment process in step #25 indicates that no peculiar part is present, it is determined that there is no significant abnormality in the hearth 11 and that clogging has occurred due to operating conditions other than the properties of the hearth 11. For example, due to a problem before the extrusion operation, coke may remain in the coke chamber 1 for a long time (30 to 50 hours). In this case, the coke temporarily fuses with the oven wall or hearth 11. The coke that fuses with the oven wall or hearth 11 creates resistance to extrusion, increasing the extrusion force of the ram head 21. As a result, clogging is induced. Therefore, in step #35, the operating conditions of the entire coke oven 100 are adjusted, and the inside of the coke chamber 1 is visually inspected and cleaned. This returns the entire coke oven 100 to normal operation. Then, the process returns to step #5, and the next coke is produced using the coke chamber 1 and the extrusion operation is carried out.

[0057] If the process proceeds to step #30, that is, if the result of the determination process in step #25 indicates that a peculiar part exists in the hearth 11, the identification process is performed. Specifically, the identification process identifies the position x1 in the furnace length direction of the coking chamber 1 where the maximum displacement of the peculiar part occurred in the hearth 11 measured in the measurement process. In the example of the displacement shown by the thin line in Figure 1 above, a position of approximately 14 m can be identified as the position x1 where the maximum displacement of the peculiar part occurred.

[0058] Furthermore, the identifying step identifies the second peak, which is the largest peak among one or more peaks that appear after the first peak, in the extrusion force waveform accumulated in the accumulating step, more specifically, in the immediately preceding extrusion force waveform, and the position x2 in the furnace length direction of the coke chamber 1 at which the second peak appeared. In the example of the extrusion force waveform shown by the thin line in Figure 2 above, the second peak, which is the largest peak after the first peak, can be identified, and the position x2 at which the second peak appeared can be identified as approximately 14 m. In a typical example, the extrusion force of the second peak is greater than the extrusion force of the first peak. However, the extrusion force of the second peak may be equal to or smaller than the extrusion force of the first peak.

[0059] Next, in step #40, a matching process is performed. Specifically, the matching process matches position x1 with position x2 to determine whether position x1 overlaps with position x2. If position x1 overlaps with position x2, the process proceeds to step #45. On the other hand, if position x1 does not overlap with position x2, the process proceeds to step #35. Here, the case where position x1 overlaps with position x2 is not limited to the case where position x1 completely coincides with position x2, but also includes the case where position x1 substantially coincides with position x2. In other words, if the absolute value of the difference between position x1 and position x2 is 100 mm or less, position x1 can be considered to overlap with position x2.

[0060] If the result of the comparison process in step #40 indicates that position x1 does not overlap with position x2 and the process proceeds to step #35, the operation of the entire coke oven 100 is returned to normal operation as described above. Then, the process returns to step #5, and the next coke is produced using the coke chamber 1 and extrusion operation is carried out.

[0061] If the process proceeds to step #45, that is, if the result of the comparison process in step #40 indicates that position x1 overlaps with position x2, a judgment process is performed. Specifically, the judgment process determines that the time has come to replace the bricks on the hearth 11 in the coking chamber 1. For example, in the displacement shown by the thin line in Figure 1 above, position x1 is approximately 14 m, and in the extrusion force waveform shown by the thin line in Figure 2 above, position x2 is approximately 14 m, and position x1 overlaps with position x2. In other words, position x1, where the maximum displacement of the convex peculiar part of the hearth 11 of the coking chamber 1 where the jamming occurred, appears, overlaps with position x2, where the second peak appeared in the immediately preceding extrusion waveform. In this case, it can be said that the jamming occurred because the ram head 21 moving within the coking chamber 1 during the extrusion operation excessively slid against or rode over the convex peculiar part of the hearth 11. Therefore, as found above, when position x1 overlaps with position x2, it can be confirmed that the jam occurs due to the singular part.

[0062] [effect] The determination method according to this embodiment goes through a series of steps (steps #5 to #45) including a pushing step, a detection step, a storage step, a cleaning step, a measurement step, a determination step, a specification step, a comparison step, and a judgment step, and finally determines that it is time to replace bricks in the hearth 11 of the coking chamber 1. To make such a final determination, the vertical displacement of the hearth 11 of the coking chamber 1 where clogging actually occurred and the pushing force waveform during the pushing operation carried out immediately before the clogging occurred are used. As described above, if there is a unique part in the displacement of the hearth 11 of the coking chamber 1 where clogging occurred, and the position x1 where the maximum displacement of the unique part appears overlaps with the position x2 where the second peak appeared in the immediately preceding pushing force waveform, it can be confirmed that the clogging occurred due to the unique part. According to the judgment method of this embodiment, when position x1 overlaps with position x2, it is judged that the time has come to replace the bricks in the hearth 11 of the coking chamber 1, so it is possible to appropriately determine the time to replace the hearth bricks in the coking chamber 1 in relation to the actual clogging that occurs. Then, if the hearth bricks are replaced based on this judgment, it becomes possible to carry out the subsequent extrusion operation without the occurrence of clogging. [Example]

[0063] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to the following examples.

[0064] In order to promote reuse, the vertical displacement of the hearth bottom was measured for several non-operating coking chambers that had frequently experienced clogging in the past. A laser-type 3D shape measuring device was used for the measurements. In all of the non-operating coking chambers, there was a convex peculiar part on the hearth bottom. The maximum displacement of the peculiar part was 35 mm or more in all cases. The position x1 where the maximum displacement appeared was always around 14 m.

[0065] Furthermore, for each non-operating coking chamber, the extrusion force waveform during the most recent extrusion operation was investigated. In all of the extrusion force waveforms, a second peak, which is the largest peak after the first peak, was observed. The position x2 where this second peak appeared was always around 14 m. In other words, in all of the non-operating coking chambers, the absolute value of the difference between positions x1 and x2 was 100 mm or less, and position x1 overlapped with position x2.

[0066] Bricks were replaced across the entire hearth of each non-operating coking chamber. At the same time as replacing the hearth bricks, the entire furnace wall was repaired. Coke was then produced and extrusion operations were carried out using each coking chamber that had been repaired in this way. As a result, the annual furnace operating rate of each coking chamber was less than 20% before the repairs, but increased to more than 90% after the repairs. This improved coke productivity.

[0067] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. [Explanation of symbols]

[0068] 100: Coke oven 1: Carbonization chamber 11: Hearth bottom 14: Extruder side kiln mouth 15: Kiln opening on the guide car side 2: Extruder 21: Ramhead 22: Ram Beam 23: Slide shoe 24: Motor 25: Rack gear 26: Pinion gear 3: Fire truck

Claims

1. A method for determining when to replace bricks at the hearth of a coke oven, comprising: an extrusion process in which coke is extruded by a ram head that moves in the furnace length direction within the carbonization chamber; a detection step of detecting the pushing force of the ram head when the ram head moving within the coking chamber passes through each position in the furnace length direction of the coking chamber during the extrusion operation; An accumulation process for accumulating an extrusion force waveform representing a transition of the extrusion force associated with each position in the furnace length direction of the coking chamber, the extrusion force waveform including at least a first peak at a position close to the start of the extrusion operation, for the extrusion force detected in the detection process; a cleaning step of stopping the extrusion operation and cleaning the inside of the carbonization chamber when clogging occurs during the extrusion operation; After the cleaning process, a measuring process of measuring a displacement in the height direction of the furnace bottom along the furnace length direction of the coking chamber; a determination step of determining whether or not a peculiar portion having a displacement exceeding a predetermined range exists in the hearth based on the result of the measurement step; If the peculiar portion is present as a result of the determination step, a determination step of identifying a position x1 in the furnace length direction of the coking chamber where the maximum displacement of the peculiar portion appears in the furnace bottom measured in the measurement step, and identifying a second peak, which is the maximum peak among one or more peaks that appear after the first peak, and a position x2 in the furnace length direction of the coking chamber where the second peak appears in the extrusion force waveform accumulated in the accumulation step; a matching step of matching the position x1 with the position x2 and determining whether the position x1 overlaps with the position x2; A method for determining the time to replace the hearth bricks of a coke oven, comprising: a judgment process for determining that the time has come to replace the hearth bricks in the coking chamber if the result of the comparison process indicates that the position x1 overlaps with the position x2.

2. 2. The method of claim 1, In the determination step, the predetermined range is a range from −30 mm to 30 mm, A method for determining the time to replace hearth bricks in a coke oven, wherein, in the comparison process and the judgment process, if the absolute value of the difference between the position x1 and the position x2 is 100 mm or less, the position x1 is deemed to overlap with the position x2.

3. 3. The determination method according to claim 1 or 2, In the measuring step, the displacement of the hearth is measured using a laser-type three-dimensional shape measuring device.

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