Coke oven operation method

Abstract

To provide an operation method for a coke oven that can suppress occurrence of coke clogging.SOLUTION: An operation method for a coke oven comprises: a measurement step (#5); a calculation step (#10); a determination step (#15); and an extrusion step (#20). In the measurement step (#5), width (H) of a ram head (12) is measured. In the calculation step (#10), a value of an index (A) expressed by the following equation (1) is calculated. In the determination step (#15), before extruding coke, it is determined whether the value of the index (A) satisfies the following formula (2). In the extrusion step (#20), if the value of the index (A) does not satisfy the following formula (2), a shape of the ram head (12) is corrected so that the following formula (2) is satisfied, and the coke is extruded using an extruder (10) containing a modified ram head (12). A is A=0.5×(W-H) (1), and A is A≤A0 (2).SELECTED DRAWING: Figure 7

Description

Technical Field

[0004] , ,

[0001] The present disclosure relates to an operation method of a coke oven.

Background Art

[0002] Coke used in ironmaking is produced by charging raw coal into a coke oven and carbonizing the coal at high temperature. The coke oven is, for example, a chamber-type coke oven. The coke oven has a structure in which carbonization chambers for carbonizing coal and combustion chambers for supplying heat to the carbonization chambers are arranged alternately in parallel, and the carbonization chambers and the combustion chambers are separated by a furnace wall made of bricks. Fuel gas burns inside the combustion chamber, and the heat of the combustion chamber is supplied to the carbonization chamber by heat conduction through the furnace wall. Raw coal at normal temperature is charged into the carbonization chamber. The coal in the carbonization chamber is promoted to carbonize by the heat from the combustion chamber and is carbonized to become coke. Coke ovens are provided at both ends of the carbonization chamber. The coke in the carbonization chamber is pushed out of the carbonization chamber by an extruder. Specifically, the coke in the carbonization chamber is pushed from one coke oven of the carbonization chamber toward the other coke oven by an extruder and discharged outside the furnace. The discharged coke is guided to a fire truck by a guide vehicle and transported by the fire truck. Hereinafter, one coke oven of the carbonization chamber is also referred to as the "extruder-side coke oven", and the other coke oven is also referred to as the "guide vehicle-side coke oven".

[0003] The extruder includes, for example, a ram beam extending from the extruder-side coke oven to the guide vehicle-side coke oven, a ram head fixed to the tip of the ram beam, and a slide shoe disposed below the ram beam and integrated with the ram beam. During the extrusion of coke, the ram head contacts the coke. At that time, the ram head transmits the driving force of the extruder to the coke. The slide shoe supports the ram beam while sliding on the furnace bottom during the extrusion of coke.

[0004] The carbonization chamber and combustion chamber extend along the direction from the extruder-side furnace opening to the guide wheel-side furnace opening, respectively. Hereafter, the direction in which the carbonization chamber and combustion chamber extend will also be referred to as the "furnace length direction." The dimensions of the carbonization chamber and combustion chamber in the furnace length direction are, for example, several tens of meters. During coke extrusion, frictional forces are generated between the coke and the furnace wall, and between the coke and the furnace bottom. Hereafter, the furnace wall and furnace bottom will be collectively referred to as the "furnace surface." In particular, if the coke is not sufficiently carbonized, or if there are irregularities in the brickwork of the furnace wall, excessive frictional resistance will be generated against the coke. In such cases, the extrudeability of the coke deteriorates.

[0005] If the extrudeability of coke deteriorates excessively, the furnace walls may be damaged or even collapse on a large scale, and in some cases, coke packing may occur. Coke packing refers to a situation where, during the extrusion of coke in the carbonization chamber, the reaction force acting on the extruder suddenly increases, preventing the extruder from pushing out the coke, and causing the coke to stop in the carbonization chamber. When coke packing occurs, the coke oven must be stopped, the coke in the carbonization chamber must be manually discharged, and then the furnace walls must be repaired. Therefore, when coke packing occurs, coke productivity decreases and repair costs increase.

[0006] Conventionally, techniques have been known to reduce the reaction force acting on the extruder during the extrusion of coke in the carbonization chamber by giving the extruder a special shape to the ram head. For example, Patent Document 1 discloses a ram head with a concave tip. In Patent Document 1, by setting the groove depth of the concave ram head to a suitable value, a force is applied to the coke toward the center of the carbonization chamber (away from the furnace wall), thereby reducing the frictional force between the coke and the furnace wall. Patent Document 2 also discloses a ram head that includes a void. In Patent Document 2, in the horizontal cross-section of the ram head, the width of the void is greater than the difference between the carbonization chamber width on the extruder side and the width of the ram head. By using this ram head to extrude coke, the coke is pushed toward the furnace wall at a distance greater than 1 / 4 of the carbonization chamber width from the furnace wall. In this case, a rotational moment toward the center of the carbonization chamber is generated in the coke, and the coke does not come into contact with the furnace wall, preventing frictional resistance, as described in Patent Document 2. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2003-213267 [Patent Document 2] Japanese Patent Application Publication No. 6-271857 [Overview of the project] [Problems that the invention aims to solve]

[0008] When coke is repeatedly extruded using an extruder, the ram head of the extruder gradually wears down. As the ram head wears down, coke packing may occur occasionally.

[0009] The purpose of this disclosure is to provide a method for operating a coke oven that can suppress the occurrence of coke packing. [Means for solving the problem]

[0010] The operating method according to this disclosure is a method for operating a coke oven, in which coke in the carbonization chamber is pushed out of the carbonization chamber using an extruder. The extruder includes a ram beam, a ram head, a slide shoe, and a motor that provides force to move the ram beam in the direction of the furnace length. The ram beam extends in the direction of the furnace length. The ram head is fixed to the tip of the ram beam. The slide shoe is positioned below the ram beam and is integrated with the ram beam. The operating method according to this disclosure comprises a measurement step, a calculation step, a determination step, and an extrusion step. In the measurement step, the width H of the ram head is measured. In the calculation step, when the width of the carbonization chamber is W, the value of index A, represented by the following formula (1), is calculated. In the determination step, before pushing out the coke with the extruder, it is determined whether the value of index A calculated in the calculation step satisfies the following formula (2), with a predetermined threshold A0. In the extrusion step, if the value of index A calculated in the calculation step satisfies the following formula (2), the coke is pushed out using the extruder described above. In the extrusion process, if the value of index A does not satisfy equation (2) below, the shape of the ram head is modified so that equation (2) below is satisfied, and the coke is extruded using an extruder that includes the modified ram head. A = 0.5 × (WH) (1) A ≤ A ≠ A ≠ (2) [Effects of the Invention]

[0011] According to the coke oven operation method described herein, the occurrence of coke packing can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows an example of the extrusion waveform in a coke oven. [Figure 2] Figure 2 shows an example of the extrusion waveform in a coke oven. [Figure 3] Figure 3 shows an example of the extrusion waveform in a coke oven. [Figure 4] Figure 4 is a schematic diagram showing the overall configuration of a coke oven. [Figure 5] Figure 5 is a cross-sectional view along line VV in Figure 4. [Figure 6] FIG. 6 is a side view of the extruder. [Figure 7] FIG. 7 is a flowchart showing an operation method of the coke oven according to the embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the state inside the carbonization chamber. [Figure 9] FIG. 9 is a diagram showing the results of the examples. [Figure 10] FIG. 10 is a diagram showing the results of the examples. **MODE FOR CARRYING OUT THE INVENTION**

[0013] The inventors of the present invention examined the factors that deteriorate the extrudability in a coke oven and focused on the reaction force acting on the extruder during the extrusion of coke. The reaction force acting on the extruder corresponds to the torque of the motor that drives the extruder, and is hereinafter also referred to as the "extrusion load". Specifically, the inventors found that they could recognize signs of abnormalities in the furnace (such as jamming) during the extrusion of coke from the transition of the extrusion load (hereinafter also referred to as the "extrusion waveform") detected according to the movement amount of the ram head of the extruder.

[0014] FIG. 1 is a diagram showing an example of the extrusion waveform of a coke oven. FIG. 1 shows the extrusion waveform when the inside of the furnace is in a sound state. A sound state inside the furnace means a state in which no abnormalities such as jamming of coke occur and the extrusion of coke is performed smoothly. The extrusion waveform shown in FIG. 1 is, for example, the extrusion waveform when a newly installed coke oven is used.

[0015] In FIG. 1, the horizontal axis indicates the position of the ram head based on the extruder side kiln mouth, that is, the movement amount of the ram head from the extruder side kiln mouth of the carbonization chamber. In FIG. 1, the movement amount of the ram head is shown as a measured value from the extruder side kiln mouth. This is the same in FIGS. 2 and 3 described later.

[0016] In FIG. 1, the vertical axis represents the extrusion load. The extrusion load is shown as a relative value when the upper limit value of the extrusion load determined from the perspective of preventing equipment damage to the extruder and protecting the furnace body is set to 1.0. That is, the extrusion load is shown as a relative value with respect to the upper limit value of the extrusion load. This is the same for each of the figures described later.

[0017] The coke in the carbonization chamber is pushed from one kiln mouth of the carbonization chamber to the other kiln mouth by an extruder after being carbonized. When the coke starts to be pushed by the extruder, it is crushed by the ram head of the extruder and the whole is compressed. At this time, a static frictional force acts between the coke and the furnace surface, and the coke remains stationary. Then, when the extrusion load increases, the frictional force between the coke and the furnace surface reaches the maximum value (maximum static frictional force), and the coke starts to move. When the coke starts to move, the coke receives a dynamic frictional force smaller than the maximum static frictional force. Therefore, after the extrusion load reaches the maximum value, it rapidly decreases.

[0018] Hereinafter, in the extrusion waveform, the period from when the extrusion load starts to rapidly increase until the rapid decrease of the extrusion load after it reaches the maximum value is completed, that is, the portion corresponding to the peak of the extrusion waveform, is referred to as the "peak" of the extrusion load. The peak that first appears when the extrusion of the coke starts is referred to as the "initial peak" of the extrusion load. In the example of the extrusion waveform shown in FIG. 1, the initial peak appears during the period when the movement amount of the ram head is from 0 to 0.9 m. Also, the value of the extrusion load when the extrusion load reaches the maximum value among the peaks is referred to as the "peak value". The peak value at the initial peak corresponds to the maximum static frictional force between the coke and the furnace surface. In the example of the extrusion waveform shown in FIG. 1, the extrusion load reaches the maximum value when the movement amount of the ram head is about 0.6 m, and the peak value is 0.15.

[0019] On the other hand, once the coke begins to move, as the ram head moves, the coke is discharged from the guide wheel side of the carbonization chamber. As a result, the amount of coke in the carbonization chamber gradually decreases, and the load required for the ram head to push the coke decreases. In other words, the extrusion load is gradually reduced. Therefore, in a healthy furnace, as is clear from the extrusion waveform shown in Figure 1, the extrusion load after the initial peak decreases substantially as the ram head moves.

[0020] In newly constructed coke ovens, the peak value at the initial peak is very small. On the other hand, in aging coke ovens, the peak value at the initial peak is large. This is thought to be because, as coke ovens age, the furnace surface of the carbonization chamber wears down, increasing the frictional force between the coke and the furnace surface, and making it easier for poor combustion and reduced heat transfer to occur, resulting in poor carbonization of the coke.

[0021] Figure 2 shows an example of the extrusion waveform of a coke oven. Figure 2 shows the extrusion waveform when the coke oven is aging and the furnace wall is bulging in some areas, or when the furnace wall is bulging. In the extrusion waveform shown in Figure 2, the peak value at the initial peak is larger than the peak value at the initial peak of the extrusion waveform shown in Figure 1. Furthermore, the extrusion load after the initial peak remains high for a while even when the ram head movement increases, in the range of ram head movement of approximately 2.0 to 6.5 m. This is thought to be because in an aging coke oven, the kinetic friction force acting between the coke and the furnace surface is greater compared to a coke oven in a healthy condition.

[0022] However, generally, the carbonization chamber is provided with a horizontal taper. In short, the width of the carbonization chamber increases from the extruder-side kiln opening to the guide wheel-side kiln opening. Due to this horizontal taper of the carbonization chamber, the clearance between the coke and the furnace wall increases as the amount of ram head movement increases during coke extrusion. Therefore, even if the coke oven deteriorates to some extent and bulging or protrusion of the furnace wall occurs, if the coke is sufficiently burnt and robust, as shown in Figure 2, the ram head movement progresses to a certain extent after the initial peak, and after the amount of ram head movement exceeds approximately 6.5 m, the extrusion load gradually decreases as the amount of ram head movement increases.

[0023] The extrusion waveform when no abnormality occurs in the coke oven has been described above with reference to Figures 1 and 2. The inventors have diligently studied the extrusion waveform when an abnormality occurs in the coke oven. As a result, the inventors have found that when an abnormality occurs in the coke oven, not only is the peak value at the initial peak (the maximum static friction force between the coke and the furnace surface) very large, but as shown in the extrusion waveform in Figure 3 described later, a peak in the extrusion load during the actual extrusion period or a significant waveform change after the initial peak occurs. The actual extrusion period refers to the period from the start of coke extrusion to the completion of extrusion, specifically the period after the initial peak of the extrusion load occurs and while the discharge of coke from the carbonization chamber is in progress.

[0024] Figure 3 shows an example of the extrusion waveform of a coke oven. Figure 3 shows the extrusion waveform when an abnormality occurs in the coke oven. When an abnormality occurs in the coke oven, the extrusion load after the initial peak may rise again immediately without decreasing. In the example shown in Figure 3, the extrusion load rises in the range of approximately 4.0 to 9.5 m of ram head movement. The inventors have found that in the case of such an extrusion waveform, coke packing occurs with a high probability. Furthermore, the inventors have newly discovered that the factor that causes the abnormal extrusion waveform shown in Figure 3 is coke lumps that spill out from between the ram head of the extruder and the furnace wall during coke extrusion and remain in the furnace.

[0025] When coke lumps spill into the furnace, they accumulate at the bottom of the furnace in front of the extruder's slide shoe. In other words, the coke lumps accumulate between the ram head and the slide shoe. This creates friction between the slide shoe, which slides against the furnace bottom, and the coke lumps, increasing the extrusion load. Additionally, the slide shoe rides up onto the coke lumps accumulated at the furnace bottom, generating mechanical stress.

[0026] When the width of the ram head is smaller than the width of the carbonization chamber, the clearance between the ram head and the furnace wall is large, making it easier for coke lumps to spill out between the ram head and the furnace wall. Therefore, as the width of the ram head decreases due to wear, coke lumps are more likely to spill into the furnace, and the extrusion load increases. Consequently, during coke extrusion, the ram head of the extruder must be designed to prevent coke lumps from spilling into the furnace as much as possible.

[0027] The coke oven operation method according to the embodiment of this disclosure has been completed based on the above findings.

[0028] The operating method according to the embodiment is a method for operating a coke oven, in which coke in the carbonization chamber is pushed out of the carbonization chamber using an extruder. The extruder includes a ram beam, a ram head, a slide shoe, and a motor that provides force to move the ram beam in the direction of the furnace length. The ram beam extends in the direction of the furnace length. The ram head is fixed to the tip of the ram beam. The slide shoe is positioned below the ram beam and is integrated with the ram beam. The operating method according to the embodiment comprises a measurement step, a calculation step, a determination step, and an extrusion step. In the measurement step, the width H of the ram head is measured. In the calculation step, when the width of the carbonization chamber is W, the value of index A, represented by the following formula (1), is calculated. In the determination step, before pushing out the coke with the extruder, it is determined whether the value of index A calculated in the calculation step satisfies the following formula (2) when a predetermined threshold A0 is set. In the extrusion step, if the value of index A calculated in the calculation step satisfies the following formula (2), the coke is pushed out using the extruder described above. In the extrusion process, if the value of index A does not satisfy equation (2) below, the shape of the ram head is modified so that equation (2) below is satisfied, and the coke is extruded using an extruder that includes the modified ram head (first configuration). A = 0.5 × (WH) (1) A ≤ A ≠ A ≠ (2)

[0029] In the operation method of the coke oven of the first configuration, in the calculation step, the value of index A is calculated from equation (1) above using the width H of the ram head measured in the measurement step. This value of index A substantially corresponds to the clearance between the ram head and one of the furnace walls when coke is extruded using this ram head. In the determination step, it is determined whether or not equation (2) above is satisfied before starting the extrusion of coke. In other words, in the determination step, the clearance between the ram head and the furnace wall is taken as index A, and it is determined whether or not the value of index A is less than or equal to a predetermined threshold A0. If index A is less than or equal to threshold A0, the width of the ram head is in an appropriate state, and the clearance between the ram head and the furnace wall is moderately small.

[0030] In the extrusion process, if the determination process determines that equation (2) above is satisfied, the coke is extruded using the extruder described above without modifying the shape of the ram head. On the other hand, if the determination process determines that equation (2) above is not satisfied, the shape of the ram head is modified to satisfy equation (2) above, and the coke is extruded using the modified extruder. In short, the determination process determines whether or not it is necessary to modify the shape of the ram head, that is, whether or not the ram head is worn out. If the ram head is worn out, its shape is modified by repair or other means, and then the coke is extruded. Thus, according to the operation method of the first configuration, the use of a worn ram head can be avoided, and as a result, coke lumps are less likely to spill out from between the ram head and the furnace wall during coke extrusion. Therefore, the extrusion load during coke extrusion can be reduced. Consequently, according to the operation method of the first configuration, the occurrence of coke packing can be suppressed.

[0031] In the operation method of the coke oven according to the first configuration, preferably, the threshold A0 satisfies the following equation (3) when the average particle size of the coke is D (second configuration). 1.3 × D ≤ A0 ≤ 1.6 × D (3)

[0032] In the second configuration of the operating method, the threshold A0 of the clearance between the ram head and the furnace wall is set to satisfy equation (3) above. Equation (3) means that the threshold A0 is set within the range of 1.3 times or more and 1.6 times or less the average particle size D of the coke. In the second configuration of the operating method, in the extrusion process, if the clearance between the ram head and the furnace wall is somewhat large in relation to the average particle size of the coke, the ram head is repaired. By modifying the shape of the ram head and increasing the width H of the ram head, the amount of coke that spills out from between the ram head and the furnace wall during coke extrusion can be reduced more reliably. Therefore, according to the second configuration of the operating method, the occurrence of coke packing can be further suppressed.

[0033] In the operation method of the first or second configuration, if the value of index A calculated in the calculation process does not satisfy the above formula (2) in the extrusion process, the shape of the ram head may be modified by build-up welding so that the above formula (2) is satisfied (third configuration). In the operation method of the third configuration, if the ram head of the extruder is worn out in the extrusion process, that is, if the ram head needs to be repaired, build-up welding is applied to the ram head. This makes it possible to modify the width H of the ram head to be about the same size as the width of a new ram head. Therefore, according to the operation method of the third configuration, the occurrence of coke packing can be suppressed.

[0034] The following describes the operation method of a coke oven according to the embodiment of this disclosure, with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

[0035] [Coke oven] The overall configuration of the coke oven will be explained with reference to Figures 4 and 5. Figure 4 is a schematic diagram showing the overall configuration of the coke oven. Figure 5 is a cross-sectional view along line VV in Figure 4. In other words, Figure 5 is a cross-sectional view perpendicular to the oven length. The coke oven has a structure in which carbonization chambers 80 and combustion chambers 90 are arranged alternately in parallel. Room temperature coal is fed into the carbonization chamber 80. The combustion chamber 90 supplies heat to the carbonization chamber 80. The heat supplied from the combustion chamber 90 causes the coal in the carbonization chamber 80 to be carbonized to coke. The coke is pushed by the extruder 10 from the extruder-side kiln opening 81 of the carbonization chamber 80 toward the guide car-side kiln opening 82 and discharged from the carbonization chamber 80. The discharged coke is guided to the fire extinguishing vehicle 70 by a guide car (not shown). The coke is then transported to the next process by the fire extinguishing vehicle 70.

[0036] The carbonization chamber 80 and the combustion chamber 90 are composed of a ceiling 83 and a furnace bottom 84. The adjacent carbonization chamber 80 and combustion chamber 90 are separated by furnace walls 85. These furnace walls 85 connect the ceiling 83 and the furnace bottom 84, respectively. Each ceiling 83 of the carbonization chamber 80 is provided with a coal charging port 86 for charging coal. The coal charging port 86 penetrates the ceiling 83.

[0037] [Extruder] Figure 6 is a side view of the extruder 10. Referring to Figure 6, the extruder 10 includes a ram beam 11, a ram head 12, a slide shoe 13, and a motor 14. The ram beam 11 extends in the direction of the furnace length. A rack gear 15 is provided at the top of the ram beam 11. The rack gear 15 extends in the direction of the furnace length.

[0038] The ram head 12 is fixed to the tip of the ram beam 11. The ram head 12 is made of, for example, general structural rolled steel (SS material). The height h of the ram head 12 is set appropriately so that the driving force of the extruder 10 can be transmitted to the coke. The height h of the ram head 12 is, for example, 6.0 m.

[0039] The slide shoe 13 is positioned below the ram beam 11 and is integrated with the ram beam 11. As coke ovens become larger, the overall length of the extruder 10 for pushing coke out of the oven (the length of the ram beam 11 in the oven-length direction) also increases. The slide shoe 13 is provided to prevent the ram beam 11 from sagging downwards. Typically, the slide shoe 13 is positioned near the tip of the ram beam 11.

[0040] A pinion gear 16 is connected to the motor 14. The pinion gear 16 rotates due to the driving force of the motor 14. The pinion gear 16 is connected to the motor 14 via a reduction gear 17. The pinion gear 16 rotates while meshing with the rack gear 15, thereby moving the ram beam 11 in the direction of the furnace length. The motor 14 is the engine that provides the force to move the ram beam 11 in the direction of the furnace length.

[0041] [Operating Method] The operating method according to this embodiment is a method for operating a coke oven in which coke in the carbonization chamber 80 is pushed out of the carbonization chamber 80 using an extruder 10. Figure 7 is a flowchart showing the operating method of the coke oven according to this embodiment. Referring to Figure 7, the operating method of this embodiment comprises a measurement step (#5), a calculation step (#10), a determination step (#15), and an extrusion step (#20).

[0042] In the measurement step (#5), the width H of the ram head 12 is measured. Specifically, the width H of the ram head 12 is defined as the average width of the ram head 12 from the bottom end to h / 3 of the height h. The method for measuring the width H of the ram head 12 is not particularly limited, but a 3D laser measuring instrument may be used.

[0043] Figure 8 is a schematic diagram showing the inside of the carbonization chamber 80. Figure 8 shows a horizontal cross-section of the inside of the carbonization chamber 80 when coke is extruded using the extruder 10. In Figure 8, the extruder-side kiln opening 81 (Figure 4) is located below, and the guide wheel-side kiln opening 82 (Figure 4) is located above. For the sake of explanation, the illustration of coke is omitted in Figure 8.

[0044] In the calculation step (#10), the value of index A, represented by the above formula (1), is calculated. From formula (1), the value of index A is calculated by dividing the difference between the width W of the carbonization chamber 80 and the width H of the ram head 12 measured in the measurement step (#5) by 2. As shown in Figure 8, the value of index A substantially corresponds to the clearance between the ram head 12 and one of the furnace walls 85 during coke extrusion using the ram head 12. However, the calculation step (#10) is performed before the start of coke extrusion, not during coke extrusion.

[0045] Referring to Figure 8, the carbonization chamber 80 is provided with a horizontal taper. In short, the width of the carbonization chamber 80 increases from the extruder-side kiln opening 81 to the guide wheel-side kiln opening 82. In this case, the width W of the carbonization chamber 80 represents the average width of the carbonization chamber 80 in the range from the extruder-side kiln opening 81 to the guide wheel-side kiln opening 82. When calculating the value of index A, the nominal value or design value may be used as the width W of the carbonization chamber 80, or a value measured with a 3D laser measuring instrument may be used.

[0046] In the determination step (#15), it is determined whether the value of index A calculated in the calculation step (#10) satisfies the above formula (2). In the determination using formula (2), it is determined whether the value of index A, which corresponds to the clearance between the ram head 12 and the furnace wall 85, is less than or equal to the threshold A0. This determination is performed before the start of coke extrusion, similar to the calculation step (#10).

[0047] Normally, when coke is repeatedly extruded using the extruder 10, the ram head 12 of the extruder 10 gradually wears down. As a result, the width H of the ram head 12 gradually decreases. As the wear of the ram head 12 progresses, the clearance between the ram head 12 and the furnace wall 85 increases. Consequently, coke lumps are more likely to spill out from between the ram head 12 and the furnace wall 85 during coke extrusion. The spilled coke lumps accumulate at the bottom of the furnace 84. As described above, the accumulation of coke lumps is a factor that causes the emergence of a peak in the extrusion load during the actual extrusion period or a significant change in the waveform after the initial peak.

[0048] Therefore, in the determination step (#15), it is determined whether the value of index A is less than or equal to the threshold A0. Based on this determination result, the ram head 12 is repaired in the extrusion step (#20) described later. The determination of index A in the determination step (#15) means determining whether the ram head 12 needs to be repaired, that is, determining whether the ram head 12 is worn out and its width H has decreased.

[0049] In the extrusion process (#20), coke is extruded using the extruder 10. However, depending on the result of the judgment process (#15), the shape of the ram head 12 of the extruder 10 may be modified before extruding the coke.

[0050] If the value of index A calculated in calculation step (#10) satisfies the above equation (2), that is, if the value of index A is less than or equal to the threshold A0, then the clearance between the ram head 12 and the furnace wall 85 is sufficiently small, and the ram head 12 is not significantly worn. In this case, there is no need to repair the ram head 12. Therefore, without repairing the ram head 12, coke extrusion is performed in the extrusion step (#20) using the extruder 10 to which the ram head 12 is attached.

[0051] On the other hand, if the value of index A calculated in the calculation process (#10) does not satisfy the above equation (2), that is, if the value of index A is greater than the threshold A0, it can be said that the clearance between the ram head 12 and the furnace wall 85 is large and the ram head 12 is worn out. In this case, the shape of the ram head 12 is modified so that the above equation (2) is satisfied. Typically, the width H of the ram head 12 is increased by repairing the ram head 12. The means of repairing the ram head 12 are not particularly limited, but for example, the shape of the ram head 12 may be modified by build-up welding. Also, when modifying the shape of the ram head 12 so that the above equation (2) is satisfied, the ram head 12 may be replaced with a new one instead of being repaired. Then, in the extrusion process (#20), the coke is extruded using the extruder 10 to which the modified ram head 12 is attached.

[0052] The threshold A0 may be set according to the average particle size D of the coke. In the example of this embodiment, the threshold A0 is set to satisfy the above equation (3). Equation (3) means that the threshold A0 is set within the range of 1.3 times or more and 1.6 times or less the average particle size D of the coke. The average particle size D is calculated according to the test and calculation method described in JIS K 2151:2004 (Test Methods for Coke). Specifically, first, the coke that has been extruded from the coke oven and cooled is sampled as a sample during the transport process. The method of sampling the sample is according to JIS M 8811:2000, for example. After drying this sample, it is sieved through multiple sieves with different mesh sizes, and the mass of the sample remaining on the mesh of each sieve and the mass of the sample that passed through the sieve with the smallest mesh size are measured. The average particle size D is calculated from the measured mass of the sample according to the procedure described in JIS K 2151:2004. When calculating the average particle size D of coke using the method described above, the coke being measured is the coke after it has been extruded from the coke oven. However, since the average particle size D of coke produced in the same carbonization chamber and under the same conditions is substantially constant, the average particle size D calculated in advance using the method described above can be used as the average particle size of coke during extrusion (in the carbonization chamber).

[0053] For example, if the threshold A0 is set to 1.6 times or less the average particle size D of the coke, the shape of the ram head 12 can be modified in the extrusion process (#20) if the clearance between the ram head 12 and the furnace wall 85 is somewhat large in relation to the average particle size D of the coke. By modifying the shape of the ram head 12 and increasing the width H of the ram head 12, the amount of coke that spills out from between the ram head 12 and the furnace wall 85 during coke extrusion can be reduced. Therefore, the threshold A0 is preferably set to 1.6 times or less the average particle size D of the coke.

[0054] On the other hand, if the threshold A0 is set to less than 1.3 times the average particle size D of the coke, the clearance between the ram head 12 and the furnace wall 85 will be too small, and there is a risk that the ram head 12 will come into contact with the furnace wall 85 during coke extrusion. If the ram head 12 comes into contact with the furnace wall 85, the frictional force that the ram head 12 receives from the furnace wall 85 will increase. Conversely, if the threshold A0 is set to 1.3 times or more the average particle size D of the coke, the frictional force that the ram head 12 receives from the furnace wall 85 during coke extrusion can be reduced. Therefore, from an operational standpoint, it is preferable to set the threshold A0 to 1.3 times or more the average particle size D of the coke. For example, if the average particle size D of the coke is 50 mm, then the threshold A0 may be set to 75 mm.

[0055] [effect] In the coke oven operation method of this embodiment, in the calculation step (#10), the value of index A is calculated from the above formula (1) using the width H of the ram head 12 measured in the measurement step (#5). The value of index A substantially corresponds to the clearance between the ram head 12 and the furnace wall 85. In the determination step (#15), before starting the coke extrusion, it is determined whether the value of index A is less than or equal to the threshold A0 using the above formula (2). In the extrusion step (#20), if the value of index A is less than or equal to the threshold A0, the coke is extruded using the extruder 10 without repairing the ram head 12. This is because the clearance between the ram head 12 and the furnace wall 85 is sufficiently small, and there is no need to repair the ram head 12. On the other hand, if the value of index A is greater than the threshold A0, the ram head 12 is repaired, and the coke is extruded using the repaired extruder 10. Thus, according to the operating method of this embodiment, the criteria for determining whether or not to repair the ram head 12 of the extruder 10 are clarified, making it possible to determine when to repair the ram head 12. Furthermore, by avoiding the use of a worn ram head 12, coke lumps are less likely to spill out from between the ram head 12 and the furnace wall 85 during coke extrusion. This reduces the extrusion load during coke extrusion. Therefore, according to the operating method of this embodiment, the occurrence of coke packing can be suppressed.

[0056] In the operating method of this embodiment, the threshold A0 of the clearance between the ram head 12 and the furnace wall 85 is set to satisfy the above equation (3). In the operating method of this embodiment, in the extrusion process (#20), if the clearance between the ram head 12 and the furnace wall 85 is large to a certain extent in relation to the average particle size D of the coke, the ram head 12 is repaired. By increasing the width H of the ram head 12, it is possible to more reliably suppress the spillage of coke lumps from between the ram head 12 and the furnace wall 85 during coke extrusion. Therefore, according to the operating method of this embodiment, the occurrence of coke packing can be further suppressed.

[0057] In the operating method of this embodiment, if the ram head 12 needs repair in the extrusion process (#20), build-up welding is performed on the ram head 12. This makes it possible to adjust the width H of the ram head 12 to approximately the same size as the width of a new ram head. Therefore, according to the operating method of this embodiment, the occurrence of coke packing can be suppressed. [Examples]

[0058] To confirm the effectiveness of the coke oven operation method according to this embodiment, the influence of the width of the ram head used for coke extrusion on the coke lumps that spill out from between the extruder's ram head and the furnace wall during coke extrusion was investigated. Specifically, coke extrusion was performed with varying ram head widths, and the height of the coke lumps accumulated at the bottom of the furnace after extrusion was measured. The main conditions were as follows. Width of carbonization chamber: 460mm Average particle size of coke: 50 mm

[0059] Figure 9 shows the results of the example. Figure 9 shows the height of the coke lumps deposited according to the width of the ram head used. In Figure 9, the horizontal axis represents the width of the ram head, and the vertical axis represents the height of the coke lumps deposited at the bottom of the furnace.

[0060] Figure 10 shows the results of the example. In Figure 10, the horizontal axis represents the width of the ram head, and the vertical axis represents the occurrence rate. Here, Figure 10 shows the occurrence rate for two different events. One occurrence rate is the probability that a peak in the extrusion load occurs during the actual extrusion period when extruding coke using a ram head of a certain width. The other occurrence rate is the probability that the reaction force (extrusion load) acting on the extruder during the actual extrusion period when extruding coke using a ram head of a certain width exceeds 50 tons.

[0061] When the ram head width is 210 mm, the lower part of the ram head is worn down, and the clearance between the ram head and the furnace wall (value of index A) is 125.0 mm. In this case, the clearance between the ram head and the furnace wall is 2.5 times the average particle size of the coke (50 mm). Referring to Figures 9 and 10, when coke is pushed out using a ram head with a width of 210 mm, the height of the coke lumps reaches 310 mm, and the occurrence rate of the two events described above was very high.

[0062] When the ram head width is 310 mm, the ram head is not significantly worn, and the clearance between the ram head and the furnace wall is 75.0 mm. In this case, the clearance between the ram head and the furnace wall is 1.5 times the average particle size of the coke. Referring to Figures 9 and 10, when coke is extruded using a ram head with a width of 310 mm, the height of the coke lumps is limited to 220 mm, and the incidence of the two events described above is reduced compared to when a ram head with a width of 210 mm is used.

[0063] When the ram head width is 325 mm, the ram head is not significantly worn, and the clearance between the ram head and the furnace wall is 67.5 mm. In this case, the clearance between the ram head and the furnace wall is 1.35 times the average particle size of the coke. Referring to Figures 9 and 10, when coke is extruded using a ram head with a width of 325 mm, the height of the coke lumps is limited to 140 mm, and the incidence of the two events described above is significantly lower compared to when a ram head with a width of 310 mm is used.

[0064] From the results shown in Figure 9, it can be seen that the greater the width of the ram head used for extruding coke, the smaller the height of the coke lumps that accumulate. Furthermore, from the results shown in Figure 10, it can be seen that the greater the width of the ram head used for extruding coke, the lower the occurrence rate of the two phenomena described above. Therefore, by modifying the shape of the ram head to increase its width, that is, by reducing the clearance between the ram head and the furnace wall, the amount of coke lumps that accumulate at the bottom of the furnace will decrease. Thus, according to the operating method of this embodiment, the extrusion load during coke extrusion can be reduced, and thereby the occurrence of coke packing can be suppressed.

[0065] The embodiments of this disclosure have been described above. However, the embodiments described above are merely examples for implementing this disclosure. Therefore, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified as appropriate without departing from the spirit of this disclosure. [Explanation of Symbols]

[0066] 10: Extruder 11: Lambbeam 12: Lamb Head 13: Slide shoe 14: Motor 80: Carbonization chamber H: Width of the Ramhead W: Width of the carbonization chamber D: Average particle size of coke A: Indicator A0: Threshold

Claims

1. A method for operating a coke oven, comprising using an extruder that includes a ram beam extending in the direction of the furnace length, a ram head fixed to the tip of the ram beam, a slide shoe positioned below the ram beam and integrated with the ram beam, and a motor that provides a force to move the ram beam in the direction of the furnace length, to push coke from the carbonization chamber out of the carbonization chamber, A measurement step of measuring the width H of the ram head, When the width of the carbonization chamber is W, the calculation step involves calculating the value of index A, which is represented by the following formula (1). Before the coke is extruded by the extruder, the value of index A calculated in the calculation step exceeds a predetermined threshold A. ０ In this case, the determination step involves determining whether the following equation (2) is satisfied, The extrusion process includes: if the value of index A calculated in the calculation step satisfies the following formula (2), the coke is extruded using the extruder; if the following formula (2) is not satisfied, the shape of the ram head is modified so that the following formula (2) is satisfied, and the coke is extruded using the extruder including the modified ram head; The threshold A0 is a method of operating a coke oven that satisfies the following equation (3), where D is the average particle size of the coke. A=0.5×(WH) (1) A≦A ０ (2) 1.3 × D ≤ A 0 ≤ 1.6 × D (3)

2. A method for operating a coke oven according to claim 1, A method for operating a coke oven, wherein, in the extrusion step, if the value of index A calculated in the calculation step does not satisfy the above formula (2), the shape of the ram head is modified by build-up welding so that the above formula (2) is satisfied.

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