Method for scraping out crumbled coke, method for manufacturing a scraping jig, and scraping jig

Abstract

To provide a method for scraping out collapsed coke, a method for manufacturing a scraping jig, and a scraping jig, that can prevent furnace wall load from becoming excessive and the scraping jig from colliding with a furnace wall, when scraping out the collapsed coke.SOLUTION: A method for scraping out collapsed coke in which the collapsed coke after clogging that has accumulated in a coke oven is scraped out by an extrusion ram equipped with a shovel-shaped scraping jig comprises: a width determining step of determining width of the scraping jig so that a length of a gap between a side wall of the scraping jig and an oven wall of the coke oven does not overlap with a predetermined range; and a scraping step of scraping out the collapsed coke using the scraping jig designed based on the width determining step, wherein the predetermined range includes a first predetermined range in which the collapsed coke is forced into the gap to cause an abnormal increase in furnace wall load, and a second predetermined range that is lower than the maximum swing width of the scraping jig when the extrusion ram is operated.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a scraping method for scraping out crumbled coke using a scraping jig attached to an extrusion ram. [Background technology]

[0002] In a chamber-type coke oven, coal charged into the carbonization chamber is carbonized, generating gas and tar, with the remaining material becoming coke. Once carbonization is complete, the lids located on both sides of the carbonization chamber in the oven's longitudinal direction are opened, and the extrusion ram of an extruder is advanced from one oven opening towards the carbonization chamber, thereby discharging the coke from the other oven opening. The discharged coke is cooled in a dry coke extinguishing system and then used as blast furnace coke, etc.

[0003] Here, the coke inside the carbonization chamber is an aggregate of coke lumps called a "coke cake." Numerous cracks are formed in the coke cake, and the main cracks extending from the furnace wall into the coal divide the coke cake into multiple coke lumps. Therefore, the coke lumps in the coke cake are contained within the carbonization chamber in a relatively orderly manner.

[0004] On the other hand, when pushing the coke cake out of the furnace, the extrusion may be hindered by carbon-derived protrusions formed on the walls of the carbonization chamber, causing the extruder to stop midway through the process, a phenomenon known as "blocking." When "blocking" occurs, it is necessary to pull back the extrusion ram, but when the extrusion ram is pulled back, the compressed and weakened coke may crumble (hereinafter also referred to as "crumbling coke"). In actual operation, this crumbled coke is removed from the carbonization chamber using a shovel-shaped scraping jig attached to the tip of the extrusion ram.

[0005] The inventors have experimentally demonstrated (hereinafter also referred to as "the experiment described in the background art") that when a scraping jig is inserted into the packed bed of crumbled coke, the furnace wall load is greater compared to when a coke cake is extruded (the experimental method will be described later). The reason for the difference in furnace wall load between extruding a coke cake and scraping crumbled coke is thought to be that the coke lumps constituting the crumbled coke are randomly piled up, and when force is applied in the furnace length direction, their arrangement is more easily changed compared to a coke cake, making it easier for the load in the direction of the furnace wall to increase.

[0006] Previously, there was no quantitative guidance regarding the movement of rams equipped with scraping jigs. As a result, the operation was often carried out based on the operator's experience to prevent excessive load from being applied to the furnace wall and causing a rupture, and there was a desire to improve the efficiency of the scraping operation.

[0007] Patent Document 1 discloses a shovel-shaped jig for a coke oven that can be stably inserted into the coke and whose shape is designed to increase the amount of coke that can be scraped out. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5994602 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Patent Document 1 completely fails to address the issue of suppressing furnace wall load during the removal of crumbled coke. Furthermore, it is necessary to avoid collisions between the removal jig and the furnace wall when removing crumbled coke. The present invention aims to solve these problems from the perspective of the shape of the removal jig. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides a method for scraping broken coke, characterized in that (1) a method for scraping broken coke after coke has been packed into a coke oven, using an extrusion ram equipped with a shovel-shaped scraping jig, the method comprising: a width determination step of determining the width of the scraping jig so that the length of the gap between the side wall of the scraping jig and the furnace wall of the coke oven does not overlap with a predetermined range; and a scraping step of scraping the broken coke using the scraping jig designed based on the width determination step, wherein the predetermined range consists of a first predetermined range in which broken coke is pressed into the gap, causing an abnormal increase in the furnace wall load; and a second predetermined range that is lower than the maximum value of the swing amplitude of the scraping jig when the extrusion ram is operated.

[0011] (2) The method for scraping out crumbled coke according to (1) above, characterized in that when the lower limit of the particle size of crumbled coke is defined as Dmin, the lower limit of the first predetermined range is Dmin, and the upper limit of the first predetermined range is a value that is 8 mm or more and 12 mm or less higher than Dmin.

[0012] (3) The method for scraping out crumbled coke as described in (2) above, characterized in that Dmin is a value of 45 mm or more and 55 mm or less.

[0013] (4) A method for scraping coke according to any one of (1) to (3) above, characterized in that a coke scraping test or a DEM analysis that reproduces the scraping test is performed, and the first predetermined range is set based on the relationship between the length of the gap and the furnace wall load derived from the results of the test.

[0014] (5) A manufacturing method for manufacturing a scoop-shaped scraping tool that is attached to an extrusion ram and used for scraping the collapsed coke after coke clogging in a coke oven. The width of the scraping tool is determined so that the length of the gap between the side wall of the scraping tool and the furnace wall of the coke oven does not overlap with a predetermined range. The predetermined range includes a first predetermined range in which the collapsed coke is press-fitted into the gap, causing an abnormal increase in the furnace wall load, and a second predetermined range that is lower than the maximum value of the swing amplitude of the scraping tool when the extrusion ram is operated. A manufacturing method for a scraping tool, characterized by the above.

[0015] (6) In a scoop-shaped scraping tool that is attached to an extrusion ram and used for scraping the collapsed coke after coke clogging in a coke oven, the width of the scraping tool is set so that the length of the gap between the side wall of the scraping tool and the furnace wall of the coke oven does not overlap with a predetermined range. The predetermined range includes a first predetermined range in which the collapsed coke is press-fitted into the gap, causing an abnormal increase in the furnace wall load, and a second predetermined range that is lower than the maximum value of the swing amplitude of the scraping tool when the extrusion ram is operated. A scraping tool, characterized by the above.

Effect of the Invention

[0016] According to the present invention, when scraping the collapsed coke, it is possible to prevent the furnace wall load from becoming excessive and the scraping tool from colliding with the furnace wall.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic plan view of a test device. [Figure 2] It is an explanatory diagram of Finding 1. [Figure 3] It is an explanatory diagram of Finding 2. [Figure 4] It is a schematic side view of a test device. [Figure 5] It is a perspective view of a scraping tool. [Figure 6] It is a graph of the analysis results of Levels 1 to 4. [Figure 7]This graph shows the relationship between the maximum furnace wall load and the width W1 of the scraping jig. [Figure 8] This graph shows the relationship between the maximum furnace wall load and the gap S1. [Figure 9] This is an explanatory diagram illustrating a method for setting the gap S1 considering both the first predetermined range and the second predetermined range (maximum swing amplitude S2: small). [Figure 10] This is an explanatory diagram illustrating a method for setting the gap S1 considering both the first predetermined range and the second predetermined range (maximum swing amplitude S2: medium). [Figure 11] This is an explanatory diagram illustrating a method for setting the gap S1 considering both the first predetermined range and the second predetermined range (maximum swing amplitude S2: large). [Modes for carrying out the invention]

[0018] The inventors conducted a test simulating scraping conditions in order to investigate the shape of a suitable scraping jig. This simulated test will be described in detail. Figure 1 is a schematic plan view of the test apparatus (cold compression test apparatus). The L-axis, H-axis, and W-axis are three mutually orthogonal axes. The L-axis corresponds to the forward direction of the extrusion ram, the W-axis corresponds to the opposing direction of the pair of side panels, and the H-axis corresponds to the height direction of the test apparatus. The definitions of the L-axis, H-axis, and W-axis are the same in the other drawings.

[0019] Referring to the figure, the test apparatus 100 comprises a pair of support members 2 and 3, a hydraulic cylinder 4, and an air cylinder 5, all of which are mounted on a base 1. The support members 2 and 3 are fixed to the base 1 so that their mounting position can be adjusted. Side panels 6 and 7 are installed between the support members 2 and 3.

[0020] Front and rear panels 8 and 9, which act as movable walls, are positioned between the hydraulic cylinder 4 and the air cylinder 5. An extrusion ram 11, which is a ram head for transmitting the pushing force to the coke, is attached to the tip of the piston rod of the hydraulic cylinder 4.

[0021] Furthermore, the air cylinder 5 is a reaction force applying means that applies a reaction force against the pushing force, and a receiving block 12 is attached to the tip of its piston rod to transmit the reaction force and receive the pushing force. The side panels 6, 7, the extrusion ram 11 and the receiving block 12 form a storage section 10 for storing coke.

[0022] Load cells 21 are provided between the front and rear panels 8 and the extrusion ram 11, and between the front and rear panels 9 and the receiving block 12. This allows for the detection of the pressing force of the hydraulic cylinder 4. Load cells 21 are also provided between the support 2 and the side panel 6, and between the support 3 and the side panel 7. This allows for the detection of the forces acting on the side panels 6 and 7, i.e., the furnace wall load.

[0023] The "experiments described in the background technology" consist of Experiment 1 and Experiment 2. In Experiment 1, after filling the storage section 10 with coke cake, the coke cake was pushed out by advancing the extrusion ram 11, and the relationship between the ram load and the furnace wall load was investigated. In Experiment 2, after placing simulated collapsed coke, which simulates collapsed coke, in the storage section 10, a conventional scraping jig was attached to the extrusion ram 11 and inserted into the simulated collapsed coke, and the relationship between the ram load and the furnace wall load was investigated. From these experimental results, it was confirmed that the furnace wall load during scraping of the simulated collapsed coke was greater than the furnace wall load during coke cake extrusion.

[0024] Typically, this test apparatus is used to determine the furnace wall load when a coke cake, subjected to extrusion force, expands in the furnace width direction. The inventors discovered a correlation between the furnace wall load and the width W1 of the scraping jig from the results of a DEM (Discrete Element Method) analysis that reproduced this test apparatus.

[0025] Specifically, we discovered a problem where the furnace wall load abnormally increases when the length of the gap between the side of the scraping jig and the furnace wall (hereinafter referred to as gap S1) overlaps with a first predetermined range (hereinafter also referred to as Finding 1). Therefore, by setting the width W1 of the scraping jig so that the length of gap S1 does not overlap with the first predetermined range, it is possible to scrape out the collapsed coke while preventing an abnormal increase in the furnace wall load. The value of the furnace wall load considered to be an abnormal increase can be set, for example, based on past operating results.

[0026] Furthermore, if the gap S1 becomes smaller than the maximum amplitude of the scraping jig's swing (hereinafter referred to as the maximum swing amplitude S2) (in other words, if it overlaps with the second predetermined range), the side wall of the scraping jig may collide with the furnace wall during scraping, potentially damaging the furnace wall (hereinafter also referred to as Finding 2). Therefore, by setting the width W1 of the scraping jig so that the length of the gap S1 does not overlap with the second predetermined range, it is possible to scrape out the crumbled coke while avoiding collision with the furnace wall. The following provides a detailed explanation of Finding 1 and Finding 2.

[0027] (Regarding Insight 1) Figure 2 is an explanatory diagram for explaining Finding 1. When the lower limit of particle size of crumbled coke is defined as Dmin, the lower limit of the first predetermined range is preferably the lower particle size limit D min That is the case. Particle size lower limit D min This refers to particles larger than the typical quality requirement for blast furnace coke (average particle size +25mm after 30 rotations of the drum test), with a sieve particle size of approximately 45mm to 55mm being a guideline. Coke particles smaller than the sieve size have little effect on the furnace wall load and are often smaller than the lower limit of the swivel of the scraping jig; therefore, they can be excluded as influencing factors that increase the furnace wall load. In other words, the gap S1 is below the lower limit of the particle size D. min If the value is less than the given value, no abnormal increase in furnace wall load due to collapsed coke being forced into gap S1 will occur. In the actual machine, when there is a blockage, cracks are generated in the coke compressed by the extrusion ram, causing the coke to break and generating collapsed coke, but it does not apply a dropping impact like a drum test. Therefore, as described above, it is desirable to set the mesh particle size as the criterion for the lower limit of the first predetermined range.

[0028] Here, the gap S1 is the lower limit D of the particle size of the collapsed coke min In the above case, whether the furnace wall load abnormally increases depends on the magnitude of the difference between the gap S1 and the lower limit D of the particle size min of the particle size. Specifically, when the difference between the gap S1 and the lower limit D of the particle size min is relatively small, the coke mass that has entered the gap S1 is sandwiched between the side wall of the scraping jig and the furnace wall, and the press-fitting state continues, so the furnace wall load abnormally increases. On the other hand, when the difference between the gap S1 and the lower limit D of the particle size min is relatively large, even if a coke mass is sandwiched in the gap S1, since there is sufficient space for the coke mass to change its orientation, the press-fitting state is immediately eliminated. Therefore, the phenomenon of abnormal increase in the furnace wall load does not occur. That is, the upper limit of the first predetermined range can be obtained by estimating the value at which the furnace wall load changes from abnormal to normal. The upper limit of the first predetermined range is preferably the lower limit D of the particle size min + X mm (where X is 8 or more and 12 or less).

[0029] The first predetermined range can be determined, for example, based on the analysis results of DEM analysis. That is, by changing the size of the gap S1 through DEM analysis and grasping in advance the maximum value of the furnace wall load for each gap S1, the first predetermined range to be avoided in design can be set. However, the first predetermined range may also be determined by conducting a scraping test of the collapsed coke using the above-described test apparatus.

[0030] Summarizing Finding 1, it is as follows. · When the size of the gap S1 is smaller than the lower limit D of the particle size of the collapsed coke min (the lower limit value of the first predetermined range), abnormal increase in the furnace wall load does not occur. If the gap S1 overlaps with the first predetermined range, an abnormal increase in the furnace wall load occurs. When the gap S1 exceeds the first predetermined range, the furnace wall load decreases and returns to normal.

[0031] (Regarding Insight 2) Figure 3 is an explanatory diagram illustrating Finding 2. Because the extrusion ram oscillates in the width direction during extrusion, if the gap S1 becomes smaller than the maximum oscillation S2, the scraping jig attached to the extrusion ram may come into contact with the furnace wall and damage it. The maximum oscillation S2 varies depending on the extruder; generally, extruders with a relatively short service life have a smaller oscillation, while extruders with a relatively long service life have a larger oscillation. Therefore, it is necessary to know the maximum oscillation S2 of the scraping jig for each extruder and design the width W1 of the scraping jig so that the gap S1 is larger than the maximum oscillation S2 of the scraping jig. In other words, the second predetermined range that the gap S1 should avoid in design is "less than the maximum oscillation S2". A scraping jig that satisfies this design condition can scrape out crumbled coke while avoiding contact with the furnace wall.

[0032] There are no particular limitations on the method for determining the amplitude of the extruder's oscillation, but for example, it can be determined by imaging the movement of the scraping jig while the extruder is actually operating and then analyzing this image data.

[0033] Therefore, by manufacturing a scraping jig that satisfies the design conditions based on findings 1 and 2, it is possible to scrape out crumbling coke while avoiding contact with the furnace wall, and while preventing an abnormal increase in the furnace wall load. Among the scraping jigs that satisfy these design conditions, it is desirable to select the scraping jig with the largest width W1. This is because increasing the width W1 of the scraping jig increases the amount of crumbled coke that can be scraped out.

[0034] (Examples) The present invention will be specifically described with reference to examples. For scraping jigs of levels 1 to 4, which have the same side plate shape but different widths W1, the furnace wall load was determined by DEM analysis. The DEM analysis was a reproduction of a coke scraping test using the test apparatus shown in Figure 4. In Figure 4, elements that have the same function as those in Figure 1 are denoted by the same reference numerals. Referring to Figure 4, the scraping jig 13 is attached to the extrusion surface of the extrusion ram 11 using fastening members (not shown). The scraping jig 13 is mounted so that the bottom surface of the scraping jig 13 and the extrusion ram 11 are substantially flush. Reference numeral 14 denotes coke lumps randomly filled in the storage section 10, simulating broken coke.

[0035] The simulated collapsed coke mass 14 can be deposited in the storage section 10 by the following method: A 140 mm thick wooden board is placed at the extrusion end of the scraping jig 13, and the space between this wooden board and the receiving block 12 is filled with coke mass to a height of 300 mm. Then, the wooden board is pulled out, and the coke mass collapses towards the scraping jig 13, so that the base of the simulated collapsed coke mass 14 reaches the end of the scraping jig 13. Coke mass with a particle size of 50 mm to 75 mm is used (i.e., particle size lower limit D min (Let this be 50 mm). The width of the storage section 10 (corresponding to the furnace width of the coke oven) shall be 450 mm. The extrusion speed of the scraping jig 13 shall be 2.3 (mm / sec).

[0036] Figure 5 is a perspective view of the scraping jig. The test scraping jig 13 is formed in the shape of a shovel, consisting of a bottom plate 131, a pair of side plates 132, and a base 133. The base 133 consists of a vertical base 133a and a top base 133b. The bottom plate 131 and the vertical base 133a are formed in a rectangular shape. The pair of side plates 132 are each formed in a shape with one corner of a rectangular plate material beveled.

[0037] Table 1 shows the dimensional conditions for the scraping jigs 13 at levels 1 to 4. The gap S1 was calculated by subtracting W1 from the furnace width of 450 mm and then taking half of that value. T is the plate thickness. [Table 1]

[0038] Figure 6 is a graph of the analysis results for each level 1 to 4, with the horizontal axis representing the extrusion time of the scraping jig (sec) and the vertical axis representing the furnace wall load (N). The maximum values ​​of the furnace wall load for each level 1 to 4 were extracted from Figure 6, and the relationship between the maximum value of the furnace wall load (vertical axis) and the width W1 of the scraping jig (horizontal axis) was plotted in Figure 7, while the relationship between the maximum value of the furnace wall load (vertical axis) and the gap S1 (horizontal axis) was plotted in Figure 8.

[0039] In this example, based on empirical rules, Level 1 was used as the base, and when the furnace wall load was higher than Level 1, it was evaluated as "abnormally increased furnace wall load." Levels 3 and 4 are defined as having a wide scraping jig width W1 and a gap S1 that is below the lower limit of coke particle size D. min Because it was smaller than (50 mm), the furnace wall load did not increase abnormally. Level 2 is when the gap S1 is below the lower particle size limit D. min The gap S1 is approximately 5 mm larger than (50 mm), and it is presumed that the coke lumps that entered the gap S1 were pressed in, resulting in an abnormal increase in the furnace wall load. In Level 1, the gap S1 is sufficiently wide, and the pressed-in state of the coke lumps is quickly resolved, so it is presumed that an abnormal increase in the furnace wall load did not occur. In other words, compared to Level 1, as the width W1 of the scraping jig increases, as in Levels 3 and 4, the furnace wall load tends to decrease, but it was confirmed that it does not decrease monotonically, but rather increases sharply midway, as in Level 2. Based on these results, the first predetermined range in which the furnace wall load abnormally increases can be set, for example, to 50 mm or more and 60 mm or less. Furthermore, the number of levels to be analyzed may be increased to more accurately estimate the upper limit of the first predetermined range.

[0040] The graphs in Figures 9 to 11 correspond to the graph in Figure 8 and are explanatory diagrams for explaining how to set the gap S1 considering both the first predetermined range and the second predetermined range. As described above, the second predetermined range is set considering the maximum swing amplitude S2, and the maximum swing amplitude S2 varies depending on the number of years the extruder has been in use.

[0041] As shown in Figure 9, the maximum amplitude S2 is equal to the lower particle size limit D. min If it is smaller than, the allowable range of the gap S1 is from the maximum amplitude S2 to the lower limit of particle size D. min , and can be considered as exceeding the upper limit of the first predetermined range. As shown in Figure 10, when the maximum amplitude S2 overlaps with the first predetermined range, the allowable range of the gap S1 can be considered as exceeding the upper limit of the first predetermined range. As shown in Figure 11, when the maximum amplitude S2 exceeds the upper limit of the first predetermined range, the allowable range of the gap S1 can be considered as exceeding the maximum amplitude S2. Narrowing the gap S1 (in other words, increasing the width W1 of the scraping jig) increases the amount of material scraped out, so it is desirable to select the minimum value within the allowable range.

[0042] By designing the scraping jig to satisfy the allowable range of the gap S1, it is possible to prevent excessive load on the furnace wall and collision of the scraping jig with the furnace wall when scraping out the collapsed coke. [Explanation of Symbols]

[0043] 1 base 2,3 Support 4 Hydraulic Cylinder 5 Air Cylinder 6,7 Side panels 8,9 Front and rear panels 10 Storage section 11 Extruded Ram 12 Receiving block 13. Scraping jig 21 Load Cells 100 200 Test equipment 131 Bottom plate part 132 Side plate part 132F Side plate front part 132F1 Front section of the first side panel 132F2 Second side panel front section 133 Base 133a Vertical base section 133b Top plate base

Claims

1. In a method for removing collapsed coke accumulated in a coke oven after coke blockage, the collapsed coke is removed using an extrusion ram equipped with a shovel-shaped scraping jig. A width determination step to determine the width of the scraping jig so that the length of the gap between the side wall of the scraping jig and the furnace wall of the coke oven does not overlap with a predetermined range, A scraping step in which the collapsed coke is scraped out using a scraping jig designed based on the width determination step, It has, The predetermined range consists of a first predetermined range in which collapsed coke is pressed into the gap, causing an abnormal increase in the furnace wall load, and a second predetermined range that is lower than the maximum value of the swing amplitude of the scraping jig when the extrusion ram is operated. When the lower limit of particle size of crumbled coke is defined as Dmin, The lower limit of the first predetermined range is Dmin, and the upper limit of the first predetermined range is a value that is 8 mm or more and 12 mm or less higher than Dmin. A method for scraping out crumbled coke, characterized by the following features.

2. The aforementioned Dmin is a value between 45 mm and 55 mm. The method for scraping out crumbled coke according to feature 1.

3. A method for scraping crumbled coke according to claim 1 or 2, characterized in that a crumbled coke scraping test or a DEM analysis that reproduces said scraping test is performed, and the first predetermined range is set based on the relationship between the length of the gap and the furnace wall load derived from the results of the test.

4. A manufacturing method for a shovel-shaped scraping jig that is attached to an extrusion ram and used to scrape out crumbled coke after it has become clogged in a coke oven, The width of the scraping jig is determined such that the length of the gap between the side wall of the scraping jig and the furnace wall of the coke oven does not overlap with a predetermined range. The predetermined range consists of a first predetermined range in which collapsed coke is pressed into the gap, causing an abnormal increase in the furnace wall load, and a second predetermined range that is lower than the maximum value of the swing amplitude of the scraping jig when the extrusion ram is operated. When the lower limit of particle size of crumbled coke is defined as Dmin, The lower limit of the first predetermined range is Dmin, and the upper limit of the first predetermined range is a value that is 8 mm or more and 12 mm or less higher than Dmin. A method for manufacturing a scraping jig characterized by the following:

Images