Segregation evaluation method of molded charcoal and manufacturing method of coke

Abstract

To provide a segregation evaluation method of molded charcoal for appropriately acquiring a ratio of molded charcoal present around an oven cover, and a manufacturing method of coke, the method appropriately controlling the ratio of molded charcoal present around the oven cover.SOLUTION: A segregation evaluation method of molded charcoal is a method of evaluating segregation of molded charcoal around an oven cover of a coke oven using a segregation test device, where the segregation device includes a hopper and a specimen box. The specimen box is rectangular parallelepiped correspondingly around the oven cover of a carbonizing chamber of the coke oven and is partitioned into plural partitions. Coke making coal is inserted into the specimen box from the hopper, and a mass ratio of around-the-oven-cover molded charcoal is acquired, the mass ratio being a ratio of the molded charcoal included in the coke making coal inserted into the around-the-oven-cover partition of the specimen box. Using the mass ratio of around-the-oven-cover molded charcoal and a mass ratio of entire molded charcoal of the molded charcoal to the total coke making coal, a segregation degree of the molded charcoal is acquired by an equation: D=A / E (where D is segregation degree, A is mass ratio of around-the-oven-cover molded charcoal, and E is mass ratio of entire molded charcoal).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating segregation of briquettes and a method for producing coke. [Background technology]

[0002] In the production of coke used in blast furnace operation, various methods have been studied to maintain good coke strength while increasing the blending ratio of inferior coal, such as non- or slightly caking coal, in a coal blend composed of molded coal and powder coal. Coal pretreatment processes are useful for obtaining the desired coke strength using a coal blend containing inferior coal.

[0003] Briquetting, a coal pretreatment process, improves the bulk density of the raw coal by blending high-density briquettes, thereby improving coke strength. The high density of briquettes also allows for the intensive blending of lower-quality coals into the briquettes without reducing coke strength. Briquetting can also be combined with other coal pretreatment processes, such as drying and crushing.

[0004] It has also been proposed to use molded coal to suppress gas leakage from coke ovens. For example, Patent Document 1 proposes a coke manufacturing method in which all coal is molded coal in order to improve coke productivity, reduce gas leakage from the coke oven furnace lid, and increase the proportion of low-quality coal in the coke raw materials.

[0005] Furthermore, Patent Document 2 has discovered that gas leakage from the furnace lid is caused by high gas pressure in the gas passage space between the furnace lid and the furnace wall at the beginning of carbonization, and proposes a coke manufacturing method in which molded coal is concentrated and charged near the furnace lid at the bottom of the coke oven to function as a spacer, thereby reducing gas pressure and suppressing gas leakage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Publication No. 2000-282051 [Patent Document 2] Japanese Patent Application Publication No. 6-212162 Summary of the Invention [Problem to be solved by the invention]

[0007] In the method of Patent Document 1, all of the raw coal is briquette, so all of the raw coal present near the furnace lid is briquette. Similarly, in the method of Patent Document 2, a large amount of briquette is present near the furnace lid. If excessive briquette is present near the furnace lid, carbon derived from the binder contained in the briquette may adhere to the furnace lid bricks, reducing the sealing performance of the furnace lid. This reduced sealing performance can lead to gas and tar leakage from the furnace lid. Furthermore, if carbon derived from the briquette adheres to the riser pipe of the coke oven and obstructs gas flow, this can cause gas leakage from the furnace lid. Therefore, when using briquette, it is necessary to properly grasp and control the amount of briquette charged around the coke oven lid.

[0008] In addition, various types of briquettes are used in coke production in coke ovens, but even if the type of briquettes charged is changed, it is desirable to produce coke by appropriately controlling the ratio of briquettes around the furnace lid so as to prevent an increase in carbon adhesion, gas leakage, and tar leakage.

[0009] Therefore, an object of the present invention is to provide a method for evaluating the segregation of briquettes in order to appropriately determine the ratio of briquettes present around the furnace lid, and a method for manufacturing coke that appropriately controls the ratio of briquettes present around the furnace lid of a coke oven. [Means for solving the problem]

[0010] The present application has been made to solve the above problems, and its gist is as follows.

[0011] (1) A method for evaluating the segregation of briquettes around a coke oven lid using a segregation test device, comprising: the segregation test apparatus includes a hopper that stores raw coal including powdered coal and briquettes, and a sample box into which the raw coal is charged from the hopper, the sample box having a rectangular parallelepiped shape corresponding to the vicinity of the furnace lid of the coke oven chamber, one end side of the sample box corresponding to the furnace lid position and the other end side of the sample box corresponding to the coal charging position of the hopper, and the sample box being divided into a plurality of sections in the length direction and height direction from the one end side to the other end side, The raw coal is dropped from the hopper and charged into the sample box; a furnace lid-periphery briquette mass ratio, which is the ratio of the briquette contained in the raw coal charged in the furnace lid-periphery section closest to the one end among the plurality of sections in the sample box, is determined; A method for evaluating the segregation of briquettes, comprising: calculating a segregation degree, which indicates the degree of segregation of the briquettes around the lid, using the calculated briquettes mass ratio around the lid and an overall briquettes mass ratio, which is the blending ratio of the briquettes in the entire raw coal, according to the following formula (I): D=A / E (I) In formula (I), D is the degree of segregation, A is the mass ratio of briquettes around the furnace lid, and E is the total mass ratio of briquettes.

[0012] (2) determining the degree of segregation of the target briquette coal to be charged into a coke oven by the briquette segregation evaluation method described in (1) above; a reference briquette used as a basis for determining the overall briquette mass ratio of the target briquette, the reference briquette having a tar addition rate, which is the mass rate of tar added when producing the briquette, in common with the target briquette; and a briquette mass ratio around the furnace lid determined by the briquette segregation evaluation method for the reference briquette and a degree of segregation of the target briquette, are substituted into formula (I) to determine the overall briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

[0013] (3) A method for evaluating the segregation of briquettes around a coke oven lid using a segregation test device, comprising: the segregation test apparatus includes a hopper that stores raw coal including powdered coal and briquettes, and a sample box into which the raw coal is charged from the hopper, the sample box having a rectangular parallelepiped shape corresponding to the vicinity of the furnace lid of the coke oven chamber, one end side of the sample box corresponding to the furnace lid position and the other end side of the sample box corresponding to the coal charging position of the hopper, and the sample box being divided into a plurality of sections in the length direction and height direction from the one end side to the other end side, The raw coal is dropped from the hopper and charged into the sample box; a furnace lid-periphery briquette mass ratio, which is the ratio of the briquette contained in the raw coal charged in the furnace lid-periphery section closest to the one end among the plurality of sections in the sample box, is determined; A method for evaluating the segregation of molded coal, characterized by using the determined molded coal mass ratio around the furnace lid and a tar addition rate, which is the mass ratio of tar added when producing the molded coal, to determine the mass ratio of tar derived from the molded coal around the furnace lid, which indicates the degree of segregation of the molded coal around the furnace lid, using the following formula (II): F=A×G (II) In formula (II), F is the mass ratio of tar derived from the briquettes around the furnace lid, A is the mass ratio of the briquettes around the furnace lid, and G is the tar addition rate.

[0014] (4) determining the degree of segregation of the target briquette coal to be charged into the coke oven by the briquette segregation evaluation method described in (1) above; The tar mass ratio derived from the briquettes around the furnace lid is calculated using the briquettes as a reference for determining the overall briquettes mass ratio, which is the blending ratio of the target briquettes in the raw coal, by the briquettes segregation evaluation method described in (3) above, and the tar addition rate of the target briquettes are substituted into the formula (II) to calculate the briquettes around the furnace lid mass ratio; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

[0015] (5) The method for evaluating segregation of molded coal according to (1) above, wherein the degree of segregation is determined by substituting the volume and sphericity determined for a molded coal of which segregation is to be evaluated into a relational expression obtained by multiple regression analysis of the degree of segregation determined for a plurality of types of molded coal by the method for evaluating segregation of molded coal and the volume and sphericity of the plurality of types of molded coal.

[0016] (6) The method for evaluating segregation of molded coal according to (1) above, wherein the degree of segregation is determined by substituting the volume and sphericity determined for a molded coal of which segregation is to be evaluated into a relational expression obtained by multiple regression analysis of the degree of segregation determined for a plurality of types of molded coal by the method for evaluating segregation of molded coal and the volume and aspect ratio of the plurality of types of molded coal.

[0017] (7) Based on the method for evaluating the segregation of briquettes described in (5) or (6) above, the degree of segregation of the target briquettes to be charged into a coke oven and the degree of segregation of a reference briquettes, which is used as a basis for determining the total briquettes mass ratio of the target briquettes and has a tar addition rate, which is the mass ratio of tar added when producing the briquettes, in common with the target briquettes, are calculated using the relational expression; the determined segregation degree of the standard briquette and the total briquette mass ratio when the standard briquette is charged into the coke oven are substituted into the formula (I) to determine the briquette mass ratio around the furnace lid of the standard briquette; The mass ratio of the briquettes around the furnace lid of the reference briquettes and the segregation degree of the target briquettes are substituted into the formula (I) to determine the total briquettes mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

[0018] (8) determining the degree of segregation of the target briquette coal to be charged into a coke oven by the briquette segregation evaluation method described in (5) or (6) above; The tar mass ratio derived from the briquettes around the furnace lid is calculated using the briquettes as a reference for determining the overall briquettes mass ratio, which is the blending ratio of the target briquettes in the raw coal, by the briquettes segregation evaluation method described in (3) above, and the tar addition rate of the target briquettes are substituted into the formula (II) to calculate the briquettes around the furnace lid mass ratio; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

[0019] (9) The angle of repose measured for several types of powder coal with different moisture contents, The degree of segregation obtained by the method for evaluating segregation of briquettes for a plurality of types of raw coals each combining the briquettes to be evaluated for segregation and the plurality of types of powder coal; The method for evaluating segregation of briquettes according to (1) above, wherein the degree of segregation is determined by substituting the angle of repose of the fine coal to be combined with the briquettes whose segregation is to be evaluated into a relational expression obtained by regression analysis of the above.

[0020] (10) Based on the method for evaluating the segregation of briquettes described in (9) above, the degree of segregation of the target briquettes to be charged into a coke oven and the degree of segregation of a reference briquettes, which is used as a basis for determining the total briquettes mass ratio of the target briquettes and has a tar addition rate, which is the mass ratio of tar added when producing the briquettes, in common with the target briquettes, are calculated using the relational expression; the determined segregation degree of the standard briquette and the total briquette mass ratio when the standard briquette is charged into the coke oven are substituted into the formula (I) to determine the briquette mass ratio around the furnace lid of the standard briquette; The mass ratio of the briquettes around the furnace lid of the reference briquettes and the segregation degree of the target briquettes are substituted into the formula (I) to determine the total briquettes mass ratio; A coke manufacturing method characterized by blending the target molded coal at the determined overall molded coal mass ratio and using raw coal blended with powdered coal having the angle of repose used when determining the degree of segregation of the target molded coal using the relationship formula.

[0021] (11) determining the degree of segregation of the target briquette coal to be charged into a coke oven by the briquette segregation evaluation method described in (9) above; The tar mass ratio derived from the briquettes around the furnace lid is calculated using the briquettes as a reference for determining the overall briquettes mass ratio, which is the blending ratio of the target briquettes in the raw coal, by the briquettes segregation evaluation method described in (3) above, and the tar addition rate of the target briquettes are substituted into the formula (II) to calculate the briquettes around the furnace lid mass ratio; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a method for evaluating the segregation of briquettes in order to appropriately grasp the ratio of briquettes present around the furnace hood, and a method for manufacturing coke that appropriately controls the ratio of briquettes present around the furnace hood of a coke oven. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a segregation testing device according to an embodiment. [Figure 2] FIG. 10 is a diagram showing the briquette mass ratios of each section of the sample box 4 obtained in the examples. [Figure 3] 1 is a graph showing the results of yield of briquette samples produced under each production condition. [Figure 4] 10 is a graph showing the results of calculating the mass ratio of tar derived from briquetted coal around the furnace lid under each condition. [Figure 5] 1 is a graph showing the relationship between the degree of segregation around the furnace lid estimated from the actual volume and sphericity, and the degree of segregation around the furnace lid obtained by the segregation test device 1, as determined in an example. [Figure 6]1 is a graph showing the relationship between the degree of segregation around the furnace hood estimated from the actual volume and aspect ratio obtained in the examples and the degree of segregation around the furnace hood obtained by the segregation test device 1. [Figure 7] 1 is a graph showing the relationship between the degree of segregation of briquettes determined by a segregation tester and the angle of repose measured for the combined pulverized coals in an example. DETAILED DESCRIPTION OF THE INVENTION

[0024] (First embodiment) This embodiment will be described with reference to the drawings. This embodiment includes a method for evaluating the segregation of briquettes and a method for producing coke. The method for evaluating the segregation of briquettes is a method for appropriately evaluating the degree to which briquettes segregate around the periphery of a coke oven lid when the briquettes are charged into the coke oven. The method for producing coke is a method for appropriately controlling the ratio of briquettes around the lid using the evaluation results of the method for evaluating the segregation of briquettes. The coke production method of this embodiment makes it possible to produce coke by blending a desired amount of briquettes while appropriately controlling the segregation of briquettes around the lid, which can cause gas and tar leakage from the coke oven lid.

[0025] In this embodiment, "segregation" of briquettes means that the proportion of briquettes present in a specific area in the coke oven chamber is higher than the proportion of briquettes in the entire coke oven chamber, and the briquettes are unevenly distributed in that area. In this embodiment, unless otherwise specified, "segregation" refers to the uneven distribution of briquettes around the furnace lid in the coke oven chamber.

[0026] In this embodiment, the ratio of briquettes (and other coals) refers to the ratio by mass unless otherwise specified. For example, when the mass ratio of briquettes in the raw coal (coal blend) around the furnace lid is higher than the mass ratio of briquettes in all the raw coals in the coking chamber, it can be said that briquettes are segregated around the furnace lid.

[0027] (Segregation evaluation method) First, a method for evaluating the segregation of briquettes will be described. Fig. 1 is a schematic diagram showing the configuration of a segregation test apparatus 1 for carrying out the segregation evaluation method of this embodiment. The segregation test apparatus 1 reproduces the charging state of raw coal around the furnace hood in the carbonization chamber of a coke oven. Then, a test using the segregation test apparatus 1 can determine the segregation degree, which indicates the degree of segregation of the target briquettes around the furnace hood.

[0028] The segregation test apparatus 1 includes a hopper 2 and a sample box 4. The hopper 2 simulates the hopper closest to the lid of the coke chamber among multiple hoppers in an actual coke oven. The hopper 2 may be large enough to accommodate the amount of raw coal to be charged into the sample box 4. As in the case of an actual coke oven, briquettes and pulverized coal may be charged into the hopper 2 in an alternating stack to prevent the briquettes from being charged unevenly into the oven. The raw coal can be charged into the sample box 4 by opening the gate plate 6. The hopper 2 is supported above the sample box 4 by, for example, a platform 8 that movably supports the hopper 2. The segregation apparatus 1 may also include a guide frame 10. The guide frame 10 guides the charging of the raw coal from the hopper 2 into the sample box 4.

[0029] The sample box 4 is a box used to simulate the charging condition of raw coal around the lid near the bottom of a coke oven. The sample box 4 is a rectangular parallelepiped and corresponds to the bottom side of the coke oven chamber around the lid. The top of the sample box 4 is open. The internal dimensions of the sample box 4 can be, for example, 1100 mm in height (H), 1050 mm in length (L), and 450 mm in width (W). The width is preferably the same as the width of the coke oven chamber of an actual coke oven (e.g., 400 mm to 600 mm). The height and length need only be 1000 mm or larger, and can be smaller than the actual oven. The height, length, and width directions of the sample box 4 correspond to the height direction of the coke oven chamber, the longitudinal direction which is the direction of the oven length, and the width direction which is the direction of the oven battery length of the coke oven.

[0030] The sample box 4 is divided into multiple sections in a grid pattern. In this embodiment, the sample box 4 has four layers in the height direction, four columns in the length direction, and one column in the width direction, for a total of 16 sections. Each section may have the same dimensions. For example, in the case of a sample box 4 with the above dimensions, one section may be 250 mm high, 262.5 mm long, and 450 mm wide. The shape of each section is preferably square when viewed from the width direction. That is, it is preferable that the dimensions in the height direction and length direction are equal. Note that the dimensions of each section are not limited to the above sizes; the length and height may be approximately twice the length, for example, and may be set to an appropriate size within the range of 250 mm to 530 mm. The number of sections within the sample box 4 is also not limited to the above number. For example, the number of sections may be any number within the range of two layers in the height direction and two columns in the length direction to four layers and four columns. The number of sections in the height direction and length direction may differ. The width direction may be one section.

[0031] The wall surface at one end of the length of the sample box 4 corresponds to the furnace lid position, and the other end is the coal loading position of the hopper 2. Raw coal is allowed to fall freely from the hopper 2 located above the sample box 4 and loaded into the sample box 4. The hopper 2 is charged with an amount of raw coal that fills the sample box 4, which has the above-mentioned dimensions.

[0032] Among the sections in the sample box 4, the section of four layers in the first row, which is the row closest to the furnace lid position on one end side, is regarded as the range around the furnace lid of the coke oven, and the degree of segregation of the briquettes in this section is evaluated. In this embodiment, the section in the first row, which is the range around the furnace lid of the sample box 4, is also referred to as furnace lid surrounding section a (shown in a dashed line frame in FIG. 1).

[0033] The flow of the segregation evaluation method using the segregation test apparatus 1 will be described. First, raw coal is charged into the sample box 4 from the hopper 2. The charged raw coal is sampled for each section of the sample box 4. Specifically, for example, the sample box 4 is provided with slits to allow the insertion of partitions, and the partitions are inserted into the slits to prevent coal other than the section to be sampled from being mixed in during sampling. Then, all of the raw coal in each section separated by the partitions is sampled from the top of the sample box 4. After sampling the upper layer, the partitions are removed and sampling of the layer below is repeated, thereby collecting raw coal for each section. Then, for each sample, the total mass of the raw coal and the mass of the briquettes are measured. The mass of the briquettes can be determined by extracting only the briquettes from the sample and measuring their mass.

[0034] Next, based on the obtained mass of raw coal and the mass of briquettes in each section, the briquettes mass ratio around the furnace lid can be calculated using the following formula (1). The briquettes mass ratio around the furnace lid is the ratio of briquettes contained in the raw coal charged in section a around the furnace lid.

[0035] The briquette mass ratio A around the furnace lid = the total mass B of briquette in the furnace lid area a ÷ the total mass C of raw coal in the furnace lid area a (1) Here, in this embodiment, the total mass B of molded coal is the sum of the masses of molded coal in each section from the first layer to the fourth layer in the first row, and the total mass C of raw coal is the sum of the masses of raw coal in each of the same sections.

[0036] The segregation degree of the target briquette can be calculated by the following formula (2) using the briquette mass ratio A around the furnace lid calculated by the above formula (1) and the total briquette mass ratio, which is the blending ratio of briquette to the entire raw coal. The segregation degree is a value indicating the degree of segregation of the target briquette around the furnace lid.

[0037] Segregation degree D = briquette mass ratio A around the furnace lid ÷ total briquette mass ratio E (2) Here, the total briquette mass ratio E is the ratio of the mass of briquette to the total mass of raw coal charged into the hopper 2, and is the blending ratio of briquette to raw coal.

[0038] When the segregation degree is 1, the mass ratio of briquettes around the furnace lid is the same as the total mass ratio of briquettes, meaning that no briquettes segregate around the furnace lid. When the segregation degree is greater than 1, segregation occurs around the furnace lid.

[0039] The inventors confirmed that the briquette mass ratio A around the furnace lid determined by the segregation evaluation method using the segregation test apparatus 1 was no different from the briquette mass ratio around the furnace lid determined using a commercial large-scale segregation test apparatus (7210 mm high x 8144 mm long x 450 mm wide). Specifically, in the commercial large-scale segregation test apparatus, the furnace lid and the charging opening are separated by approximately 2000 mm, with the area around the furnace lid being approximately 1000 mm from the furnace lid and the area directly below the charging opening being approximately 1000 to 3000 mm from the furnace lid, sandwiched between the charging opening and the charging opening. The total briquette mass ratio around the furnace lid and the briquette mass ratio around the furnace lid were determined using the commercial large-scale segregation test apparatus. Using a graph with the total briquette mass ratio on the horizontal axis and the briquette mass ratio around the furnace lid on the vertical axis, the results of the segregation test apparatus 1 and the commercial large-scale segregation test apparatus were compared within a total briquette mass ratio range of 20 to 40%, confirming no difference. Therefore, the segregation test device 1 can accurately evaluate the degree of segregation of the briquettes.

[0040] (Coke manufacturing method) Next, a method for producing coke according to this embodiment will be described. The coke production method involves determining an overall briquette mass ratio (briquette blending ratio) that provides an appropriate briquette mass ratio around the furnace hood when using raw coal (target raw coal) blended with a desired briquette (target briquette), and using raw coal blended with the briquette at the determined ratio. The overall briquette mass ratio of the target briquette is set using the briquette mass ratio A of the furnace hood briquette mass ratio A of the raw coal (reference raw coal) blended with a reference briquette (reference briquette). The tar addition rate, which is the mass ratio of tar added when producing the briquette, is the same for both the reference briquette and the target briquette. The tar addition rate when producing the briquette is calculated by (mass of tar added when producing the briquette) / (mass of the total briquette)×100. The flow of the coke production method according to this embodiment will be described below.

[0041] As an example, the reference molded coal is the molded coal currently being used to produce coke in a coke oven, and the target molded coal is the molded coal to be used next. Assume that carbon deposition and the associated gas and tar leakage are appropriately suppressed in coke production using the current reference raw coal. The blending ratio (total molded coal mass ratio) of the target molded coal to be used next is determined so that the mass ratio of molded coal around the furnace lid in the target molded coal to be used next is equivalent to the mass ratio of molded coal around the furnace lid in the current reference molded coal.

[0042] The segregation degree D of the currently used standard briquette is determined by the above-mentioned segregation evaluation method using the segregation test apparatus 1. Specifically, the mass ratio A of the briquette around the furnace hood of the standard raw coal is determined by testing. Then, the determined mass ratio A of the briquette around the furnace hood and the total mass ratio E of the briquette, which is the blending ratio of the currently used standard briquette, are used to calculate equation (2) to determine the segregation degree D of the standard briquette.

[0043] Similarly, the segregation degree D of the target molded coal to be used next is determined using the segregation test device 1. It has been confirmed that the segregation degree D hardly changes when the blending ratio of the molded coal changes by about 5%, but it is preferable that the blending ratio of the target molded coal in the test be the same as the blending ratio of the reference molded coal.

[0044] Then, the total briquette mass ratio E is calculated by substituting the briquette mass ratio A around the furnace lid calculated for the reference briquette and the segregation degree D of the target briquette into equation (2). That is, the total briquette mass ratio E can be calculated by: total briquette mass ratio E = briquette mass ratio A around the furnace lid of the reference briquette / segregation degree D of the target briquette. To make the briquette mass ratio A around the furnace lid after switching to the target briquette equivalent to that of the current reference briquette, the briquette mass ratio A around the furnace lid of the current reference briquette is substituted into the equation. Coke is then produced using raw coal blended with the target briquette at the calculated total briquette mass ratio E.

[0045] For example, if the mass ratio A of the briquettes around the furnace lid of the current standard briquettes is 40% and the segregation degree D of the target briquettes is 1.1, the overall mass ratio E of the target briquettes can be calculated as 40 / 1.1 ≒ 36.36%. If coke is produced using raw coal that contains 36.36% of the target briquettes, the mass ratio of the briquettes around the furnace lid can be made equivalent to the mass ratio of the briquettes around the furnace lid of the currently used standard briquettes.

[0046] Therefore, according to the method of the present embodiment, coke can be produced using raw coal blended with the desired briquettes in a blending ratio that results in an appropriate briquette mass ratio around the furnace lid. In a current coke oven using a standard raw coal, if carbon deposition and the associated gas and tar leakage are not present or are suppressed to an appropriate range, even when the desired target briquettes are switched to, the briquettes mass ratio around the furnace lid can be made equivalent to that of the standard briquettes, allowing coke to be produced without increasing carbon deposition, gas leakage, or tar leakage.

[0047] (Second embodiment) Research by the present inventors has revealed that the segregation degree determined by the segregation evaluation method described in the first embodiment is correlated with the volume and sphericity of the briquette. It has also been found that the segregation degree is correlated with the volume and aspect ratio of the briquette. This embodiment provides a segregation evaluation method that estimates the segregation degree of a target briquette from the volume, sphericity, or aspect ratio of the briquette, and a coke manufacturing method that sets the overall briquette mass ratio E (blending ratio) of the target briquette using the segregation degree determined by the segregation evaluation method. Since the segregation degree of briquette is correlated with the sphericity and aspect ratio, it is believed that a correlation can also be obtained using indicators that represent the circularity or other shapes of the briquette.

[0048] First, the segregation evaluation method for briquettes is as follows: The segregation degree of various briquettes is determined in advance by the segregation evaluation method of the first embodiment, and the volume and sphericity of the same briquettes are also determined.

[0049] The volume (actual volume) can be determined, for example, by a small-volume apparent density measurement method. The sphericity can be determined, for example, by calculating the 3D CAD volume and 3D CAD surface area using a one-shot 3D shape measuring instrument, and then using the calculated values, as Wadell's sphericity (= surface area of ​​a sphere of equal volume ÷ 3D CAD surface area). The aspect ratio can be determined, for example, by viewing the molded coal from the direction in which the projected area is maximized, and dividing the minor axis length by the major axis length, where the minimum width of the molded coal is the minor axis length and the maximum width of the molded coal in the direction perpendicular to the minimum width direction is the major axis length.

[0050] Next, the data obtained by the above method is subjected to multiple regression analysis using the degree of segregation as the objective variable and the volume and sphericity or aspect ratio of the briquette as explanatory variables, and a relational equation, which is the regression equation, is obtained. The relational equation between the degree of segregation and the volume and sphericity of the briquette is as follows: Degree of segregation = Actual volume of briquette × a + sphericity of briquette × b + c The relationship between the degree of segregation and the volume and aspect ratio of the briquette is given by: Segregation degree = Actual volume of briquette × a + Aspect ratio of briquette × b + c In the above formula, a and b are regression coefficients, and c is a constant.

[0051] Next, the volume and sphericity or aspect ratio of the target molded coal for which segregation is to be evaluated are determined by the above-described method. Then, the determined volume and sphericity or aspect ratio are substituted into the above-described relational expression, whereby the segregation degree of the target molded coal can be determined.

[0052] Next, the method for producing coke will be described. First, based on the segregation evaluation method described above, the segregation degree D of the target briquette and the segregation degree D of the reference briquette are calculated using the relational expression obtained by the multiple regression analysis described above.

[0053] Next, the determined segregation degree D of the standard briquette and the total briquette mass ratio E when the standard briquette is charged into the coke oven are substituted into the above formula (2) to determine the briquette mass ratio A around the furnace lid of the standard briquette. If the briquette mass ratio A around the furnace lid of the standard briquette has already been calculated using Segregation Evaluation Test 1, that value may be used.

[0054] Then, the briquette mass ratio A of the reference briquette around the furnace lid and the segregation degree D of the target briquette calculated using the above relational expression are applied to equation (2) to calculate the total briquette mass ratio E. Coke can be produced using raw coal blended with the target briquette at the calculated total briquette mass ratio E.

[0055] According to the method of the present embodiment, by previously determining the relational expressions between the degree of segregation and the volume and sphericity of the briquette, it is possible to determine the degree of segregation of a desired briquette without performing segregation evaluation using the segregation test apparatus 1. Then, the appropriate blending ratio of the target briquette can be set using the degree of segregation.

[0056] (Third embodiment) This embodiment is a method for determining the segregation degree using yet another estimation method. Research by the present inventors has revealed that the segregation degree of briquettes is correlated with the angle of repose of the fine coal blended with the raw coal. Therefore, this embodiment is a method for determining the segregation degree using the angle of repose of the fine coal, which is correlated with the segregation degree, and setting the blending ratio of the target briquettes.

[0057] The segregation evaluation method for briquette coal is as follows: First, raw coals are prepared by blending multiple types of powder coal with the target briquette coal, each having a different moisture content, and the segregation degree of each raw coal is determined using the segregation test apparatus 1 according to the method described in the first embodiment.

[0058] The angle of repose is also determined for pulverized coal at each moisture content. The angle of repose is measured using an improved ASTM bulk density measuring device (Seitou et al., Coke Circular, 30(11), 13-5(1981)) with improved conditions in a bulk density test conforming to ASTM D 291-86. The angle of repose can be determined as the angle between the slope and the bottom of the piled sample formed when 34 kg of pulverized coal sample is dropped from a height of 2 m.

[0059] Then, the relationship between this angle of repose and the corresponding degree of segregation is determined. Specifically, a regression equation is determined by performing a regression analysis on the data obtained in the above test, using the degree of segregation as the objective variable and the measured angle of repose as the explanatory variable. By using the obtained regression equation as the relationship between the degree of segregation and the angle of repose, the degree of segregation of briquette coal when using powdered coal with a desired moisture content can be determined. The relationship between the angle of repose and the degree of segregation can be determined for each type of briquette coal.

[0060] Next, in the coke manufacturing method, based on the above-mentioned method for evaluating segregation of briquettes, the segregation degree D of the target briquettes to be charged into a coke oven and the segregation degree D of the reference briquettes are calculated using the relational equation obtained by the above-mentioned regression analysis. The segregation degree D can be calculated using the relational equation for the target briquettes and the relational equation for the reference briquettes. The angle of repose of the powdered coal to be substituted into the relational equation can be the angle of repose of the powdered coal used in combination with the reference briquettes and the angle of repose of the powdered coal to be used in combination with the target briquettes, respectively.

[0061] Next, the determined segregation degree D of the standard briquette and the total briquette mass ratio E when the standard briquette is charged into the coke oven are substituted into the above formula (2) to determine the briquette mass ratio A around the furnace hood of the standard briquette. The determined briquette mass ratio A around the furnace hood of the standard briquette and the segregation degree D of the target briquette determined using the above formula are then applied to formula (2) to determine the total briquette mass ratio E. Coke can then be produced using raw coal blended with the target briquette at the determined total briquette mass ratio E. The powdered coal to be blended with the raw coal can be powdered coal having the angle of repose used to determine the briquette segregation degree D using the above formula.

[0062] (Fourth embodiment) This embodiment is a method for evaluating segregation of a target raw coal blended with a target molded coal by determining the tar mass ratio derived from the molded coal around the furnace lid (hereinafter also referred to as the "tar mass ratio derived from the molded coal around the furnace lid") using the molded coal mass ratio A around the furnace lid determined using the segregation test apparatus 1 shown in the first embodiment.

[0063] Furthermore, this embodiment is a method for producing coke using raw coal blended with target briquettes, in which the overall briquette mass ratio E (briquette blending ratio) is calculated so that the tar mass ratio derived from the briquette around the furnace hood is the same (equivalent) as the tar mass ratio derived from the briquette around the furnace hood in the reference raw coal blended with the reference briquette, and the briquette is blended in the calculated ratio. In the coke production method of the first embodiment, the overall briquette mass ratio E (blending ratio) of the target briquette is calculated so that the briquette mass ratio A derived from the briquette around the furnace hood is the same as that of the reference briquette, but in this embodiment, the overall briquette mass ratio (blending ratio) of the target briquette is calculated so that the amount of tar derived from the briquette around the furnace hood is the same between the reference briquette and the target briquette.

[0064] In the first embodiment, it was assumed that the tar addition rate during the production of the reference molded coal and the target molded coal (hereinafter referred to as the "tar addition rate during the production of the molded coal" or simply the "tar addition rate") was basically the same. In contrast, according to the method of this embodiment, when target molded coal with a tar addition rate during the production of the molded coal different from that of the reference molded coal is used, coke can be produced using raw coal blended with the target molded coal at a blending ratio that results in an appropriate amount of tar derived from the molded coal around the furnace lid. As a result, if the operation is such that gas leakage or tar leakage does not occur with the reference molded coal, the amount of tar around the furnace lid, which is a cause of gas leakage or tar leakage, can also be controlled for the target molded coal to be the same as for the reference molded coal. Therefore, the method of this embodiment can also produce coke without increasing gas leakage or tar leakage. The method of this embodiment will be specifically described below.

[0065] The method for evaluating segregation of briquettes of this embodiment is used to determine the mass ratio of tar derived from the briquettes around the furnace lid for a reference raw coal blended with a reference briquettes. Specifically, the segregation test apparatus 1 and the above-mentioned formula (1) are used to determine the mass ratio A of the briquettes around the furnace lid for the reference briquettes according to the method described in the first embodiment. Then, the mass ratio A of the briquettes around the furnace lid for the reference briquettes and the tar addition rate of the reference briquettes during briquette production are substituted into the following formula (3), whereby the mass ratio of tar derived from the briquettes around the furnace lid for the reference briquettes (reference raw coal) can be determined.

[0066] Tar mass ratio derived from briquettes around the furnace lid F = briquettes mass ratio A around the furnace lid × tar addition rate during briquettes production G (3) In formula (3), the tar addition rate G during molded coal production is the mass ratio of tar added as a binder during the production of the molded coal. (Mass of tar added when producing molded coal) / (Total mass of molded coal) x 100 The tar mass ratio F derived from the briquette around the furnace lid is a ratio calculated by multiplying the briquette mass ratio A around the furnace lid by the tar addition rate G during the production of the briquette, as shown in formula (3), and is the mass ratio of tar contained in the briquette around the furnace lid. The tar mass ratio F derived from the briquette around the furnace lid is a value indicating the degree of segregation of the briquette around the furnace lid, based on the amount of tar around the furnace lid that contributes to tar and gas leakage from the furnace lid. The larger the tar mass ratio F derived from the briquette around the furnace lid, the more the briquette segregates around the furnace lid based on the tar amount. This concludes the method for evaluating the segregation of briquette around the furnace lid of this embodiment. The segregation evaluation method of this embodiment allows the degree of segregation of the briquette around the furnace lid to be appropriately evaluated, even between briquette with different tar addition rates G during the production of the briquette, based on the amount of tar contained in the briquette around the furnace lid.

[0067] Then, for the target molded coal, the lid-periphery molded coal mass ratio A is calculated using equation (3) when the lid-periphery molded coal tar mass ratio F is the same as that of the reference molded coal (reference raw coal). That is, the lid-periphery molded coal mass ratio A is calculated by substituting the lid-periphery molded coal tar mass ratio F of the reference molded coal calculated as described above and the tar addition rate G of the target molded coal during molded coal production into equation (3). The lid-periphery molded coal mass ratio A calculated is the lid-periphery molded coal mass ratio of the target molded coal such that the amount of tar present around the furnace lid is equivalent to that of the reference molded coal (reference raw coal).

[0068] Furthermore, for the target briquette to be used in coke production, the briquette mass ratio A around the furnace hood is determined using segregation test apparatus 1 and equation (1). In this test, the overall briquette mass ratio E (briquette blending ratio) of the target raw coal blended with the target briquette is preferably set to the same ratio as the overall briquette mass ratio E of the reference briquette, as described above. Then, using the overall briquette mass ratio E of the target briquette and the determined briquette mass ratio A around the furnace hood, the segregation degree D of the target briquette is determined using equation (2) described above. Note that the step of determining the segregation degree D for this target briquette can be performed at any time, as long as it is performed before the step of calculating the overall briquette mass ratio E of the target briquette.

[0069] Next, as described above, the lid-periphery briquette mass ratio A is calculated using Equation (3) assuming that the lid-periphery briquette tar mass ratio F is the same as that of the reference briquette, and the segregation degree D of the target briquette calculated using the segregation test apparatus 1 is substituted into Equation (2), thereby determining the overall briquette mass ratio E of the target briquette. In other words, the overall briquette mass ratio E can be calculated by: E = lid-periphery briquette mass ratio A of the target briquette / segregation degree D of the target briquette. Then, coke can be produced using raw coal blended with the target briquette at the determined overall briquette mass ratio E.

[0070] According to the method of the present embodiment, coke can be produced by determining the blending ratio of the target molded coal so that the amount of tar around the furnace lid is equivalent to the amount of tar around the furnace lid when coke is produced using the reference molded coal. When producing coke by changing from the reference molded coal to the target molded coal, it is thought that gas leakage and tar leakage will not worsen as long as the tar amount (mass ratio) around the furnace lid does not change. Therefore, the method of the present embodiment also makes it possible to produce coke without increasing gas leakage and tar leakage.

[0071] For example, when a molded coal having a lower tar addition rate G during molded coal production than that of a reference molded coal is used as the target molded coal, the method of this embodiment using equations (2) and (3) will result in a higher overall molded coal mass ratio E (blending ratio) of the target molded coal than that of the reference molded coal. In other words, when changing to a molded coal having a lower tar addition rate G during molded coal production in coke production, if the blending ratio of the molded coal is set using the method of this embodiment, it is possible to increase the amount of molded coal used to produce coke while maintaining an appropriate amount of tar around the furnace lid and suppressing tar leakage, etc.

[0072] Note that if molded coal is produced by reducing the amount of tar added during molded coal production, the yield of the molded coal may decrease. Therefore, when using molded coal with a lower tar addition rate G during molded coal production, it is preferable to produce molded coal so as to maintain the yield. The method for maintaining the yield is not particularly limited as long as it can improve the yield. For example, the yield during molded coal production can be improved by increasing the mixing temperature during molded coal production.

[0073] In this embodiment, the segregation degree D of the target briquette is determined using the segregation test apparatus 1 according to the method described in the first embodiment, but the present invention is not limited to this. The segregation degree D of the target briquette can be determined by the method described in the second embodiment. That is, the segregation degree D of the target briquette can be determined using a previously determined relationship between the segregation degree, the volume, and the sphericity of the briquette, and the total briquette mass ratio E of the target briquette can be determined using the segregation degree D. The segregation degree D of the target briquette can also be determined by the method described in the third embodiment. That is, the segregation degree D of the target briquette can be determined using a previously determined relationship between the segregation degree and the angle of repose of the fine coal, and the total briquette mass ratio E of the target briquette can be determined using the segregation degree D. [Example]

[0074] <Example 1: Segregation evaluation of molded coal using a segregation test device> The segregation degree of a plurality of briquettes was determined using the segregation test device 1.

[0075] (Coal used) The powdered coal was prepared with a crushed particle size of approximately 85% by mass, with a moisture content of 10% by mass. The molded coal was produced by molding powdered coal with a crushed particle size of 90% by mass, with a double-roll molding machine. A tar-based binder was used as the liquid binder, and asphalt pitch (ASP) was used as the solid binder.

[0076] (Evaluation of volume, surface area, and sphericity of molded coal) The volume (actual volume) of the molded coals produced was determined using a small-volume apparent density measurement method. A one-shot 3D shape measuring instrument (Keyence Corporation, VR-3100) was used to create a 3D CAD drawing of the molded coals, and the volume (3D CAD volume) and surface area (3D CAD surface area) were calculated using an analysis application. Wadell's sphericity (= surface area of ​​a sphere of equal volume divided by 3D CAD surface area) was then calculated based on the volume and surface area determined using the analysis application of the measuring instrument. A sphericity of 1 indicates a sphere, with values ​​closer to 1 indicating fewer irregularities and a more spherical shape. The volume, sphericity, etc. of each molded coal actually produced are shown in Table 1.

[0077] [Table 1]

[0078] (Evaluation of segregation of briquette coal) For each molded coal, segregation evaluation was performed using the segregation test apparatus 1, and the segregation degree D calculated using the above formula (2) was determined. The segregation test apparatus 1 is the apparatus shown in FIG. 1 described in the above embodiment, and the internal dimensions of the sample box 4 are 1100 mm in height, 1050 mm in length, and 450 mm in width. The sample box 4 is divided into 16 sections, with four rows in the length direction and four layers in the height direction, and the dimensions of each section are 250 mm in height, 262.5 mm in length, and 450 mm in width.

[0079] When raw coal was prepared by blending powder coal with a moisture content of 10% and each briquette in Table 1 at a mass ratio of 30%, the total briquette mass ratio E, the briquette mass ratio A around the furnace lid, and the segregation degree D around the furnace lid were calculated. The results are shown in Table 2. As an example, the briquette mass ratios of each category in sample box 4 calculated for briquette a) are shown in Figure 2.

[0080] [Table 2]

[0081] From the values ​​shown in Tables 1 and 2, it can be seen that briquettes with larger actual volumes tend to have a greater degree of segregation around the furnace lid. It can also be seen that even if the actual volumes are the same (or similar), briquettes with a sphericity closer to 1 tend to have a greater degree of segregation around the furnace lid. For example, briquettes e) and f) have the same actual volume, but f), which has a sphericity closer to 1, has a greater degree of segregation than e). Furthermore, between briquettes b) and d), which have similar actual volumes, b), which has a sphericity closer to 1, has a greater degree of segregation than d).

[0082] <Example 2: Calculation of total briquette mass ratio of briquette> (Calculation example 1) An example will be described in which the overall briquette mass ratio E (briquette blending ratio) was calculated for the briquette produced in Example 1 above using the method described in the first embodiment. As an example, when switching from briquette b) to briquette c) in coke production in a coke oven, the overall briquette mass ratio E was calculated for charging briquette c) while maintaining the same briquette mass ratio around the furnace lid before and after the switch. Briquette b) is the reference briquette, and briquette c) is the target briquette. The overall briquette mass ratio E for briquette b) was set to 30%.

[0083] The briquette mass ratio A around the furnace lid for briquette b) is calculated from the above formula (2) as follows: segregation degree D × total briquette mass ratio E = 1.15 × 30 = 34.5%. When the briquette mass ratio A around the furnace lid is the same for all briquette c), the total briquette mass ratio E is calculated from formula (2) as follows: total briquette mass ratio E = briquette mass ratio A around the furnace lid / segregation degree D = 34.5 / 1.05 = 32.9% since the segregation degree of briquette c) is 1.05.

[0084] When switching from briquette b) to briquette c), it is thought that coke can be produced using briquette c) by blending briquette c) in the raw coal at a ratio of 32.9% and keeping the briquette mass ratio around the furnace lid the same before and after the switch. In addition, briquette b) and c) have the same gap width between the rolls of the briquetting machine, and by using c), which is produced by changing the cup volume from 30 cc for b) to about one-third, 9 cc, an increase in the overall briquette mass ratio E of the briquette can be expected by about 3%, keeping the briquette mass ratio around the furnace lid the same.

[0085] (Calculation example 2) In calculation example 2, under the conditions that the gap width between the molding rolls was the same, the cup shape was also the same, and the cup volume of the target molded coal was 1 / 3 of that of the reference molded coal, it was confirmed whether the mass ratio A of the molded coal around the furnace lid of both cases would be equivalent when the overall molded coal mass ratio E was increased by 3%. The molded coals used were a) as the reference molded coal and h) as the target molded coal. The cup volume of molded coal a) was 30 cc, and h) was 1 / 3 of that, or 10 cc, and the gap was 10 mm, both in common. The blending ratio of a) was 30%, and molded coal h) was increased by 3% to 33%.

[0086] As shown in Table 2, for briquette a), the briquette mass ratio A around the furnace lid was 41.3% and the segregation degree was 1.36. For briquette h), the overall briquette mass ratio was set to 33%, and when testing was performed using segregation test equipment 1, the briquette mass ratio A around the furnace lid was 40.9% and the segregation degree was 1.24. Therefore, when switching from briquette a) to h), it was confirmed that by increasing the blending ratio (overall briquette mass ratio E) by 3%, the briquette mass ratio A around the furnace lid could be made to be approximately 41%, which is equivalent.

[0087] This example confirmed that by using the degree of segregation around the furnace lid, it is possible to produce coke when using the desired molded coal without changing the mass ratio of molded coal around the furnace lid.

[0088] <Example 3: Calculation example using the tar mass ratio F derived from molded coal around the furnace lid> An example will be described in which a case is examined in which briquette (target briquette) in which the tar addition rate G during briquette production is reduced compared to a standard briquette (standard briquette) is used.

[0089] (Confirmation of briquette yield) First, we investigated the manufacturing conditions under which yield can be maintained when using molded coal with a reduced tar addition rate G during molded coal manufacturing. For molded coal d) shown in Example 1, we varied the kneading temperature as a manufacturing condition to check the change in yield. We found that the yield remained high at a kneading temperature of 85°C or higher. Therefore, we set the kneading temperature to 85°C and varied the tar addition rate G during molded coal manufacturing to check the yield. Specifically, using molded coal d) (cup volume 30cc) manufactured at a kneading temperature of 70°C and a tar addition rate G during molded coal manufacturing of 7%, we checked the yield for each of the following molded coals: Condition 1, manufactured at a kneading temperature of 85°C; Condition 2, manufactured at a kneading temperature of 85°C and a tar addition rate G of 6.4% during molded coal manufacturing; and Condition 3, manufactured at a kneading temperature of 85°C and a tar addition rate G of 5.5% during molded coal manufacturing. The yield of the molded coal was evaluated by dropping the molded sample from a height of 2.5 m 10 times and then sieving it through a 15 mm sieve. The weight of the sample on the sieve (+10 mm particles) was then measured, and the weight ratio of the +10 mm particles to the total weight of the molded coal was calculated.

[0090] Figure 3 shows the yield results for molded coal samples produced under each production condition. It was confirmed that increasing the mixing temperature compared to the base temperature of 70°C improved the yield. It was also confirmed that even when the tar content ratio G during molded coal production was reduced from 7% to 6.4% at a mixing temperature of 85°C, the yield was still higher than under the base conditions. Furthermore, it was confirmed that a tar content ratio G of 5.5% during molded coal production at a mixing temperature of 85°C achieved a yield equivalent to that of the base conditions. These results are likely to be similarly confirmed even when the volume and shape of the molded coal are different. In other words, even if the volume and shape of the molded coal are different, by increasing the mixing temperature up to approximately 85°C, molded coal with a reduced tar content G can be produced while maintaining a yield equivalent to that of the base. It is also believed that the tar content ratio G during molded coal production can be reduced by adjusting factors other than the mixing temperature, such as the molding roll rotation speed, the moisture content of the coal, and the crushing particle size.

[0091] (Calculation example for molded coal with a reduced tar addition rate G during molded coal production) Next, Figure 4 shows the results of calculating the tar mass ratio F derived from the briquettes around the furnace lid for examples No. 1 to No. 3. No. 1 is the base condition. In No. 1, raw coal was used, in which briquettes (d) were blended with powdered coal with a moisture content of 10% at an overall briquette mass ratio E (blending ratio) of 25%. When the mass ratio A of the briquettes around the furnace lid for this raw coal was evaluated using segregation test device 1, it was found to be 30.5%. As mentioned above, the tar addition rate G during the production of briquettes for No. 1 was 7%. Therefore, using equation (3), the tar mass ratio F derived from the briquettes around the furnace lid was calculated as F = A × G = 30.5 × 7 ÷ 100 ≒ 2.14%.

[0092] No. 2 is a case where raw coal was blended with powder coal with a moisture content of 10% and briquette d) at an overall briquette mass ratio E (blending ratio) of 30%. The mass ratio A of the briquette around the furnace lid in sample box 4 of the segregation test device 1 was evaluated and found to be 35.8%. Since the tar addition rate G during briquette production was 7%, the mass ratio F of tar derived from the briquette around the furnace lid was calculated using equation (3) as 35.8 × 7 ÷ 100 ≒ 2.51%. Compared to No. 1 (base condition), where the same briquette d) was blended at a mass ratio of 25%, the mass ratio F of tar derived from the briquette around the furnace lid increased.

[0093] In contrast, No. 3 is an example in which the mixing temperature was increased to 85°C and the tar addition rate G during molded coal production was reduced to 5.5%. The overall molded coal mass ratio E was 30%, the same as No. 2. The molded coal mass ratio A around the furnace lid is 35.8%, since it is the same regardless of the tar addition rate G as long as the overall molded coal mass ratio E is the same. In the case of No. 3, the tar mass ratio F derived from the molded coal around the furnace lid is calculated from equation (3) as 35.8 × 5.5 ÷ 100 ≒ 1.97%. This is the same value as the tar mass ratio F derived from the molded coal around the furnace lid under the base conditions. These results show that by using molded coal with a reduced tar addition rate, the amount of tar around the furnace lid (tar mass ratio F derived from the molded coal around the furnace lid) does not increase even if the overall molded coal mass ratio (blending ratio) E is increased from 25% to 30%.

[0094] This example confirmed that by using the tar mass ratio F derived from the molded coal around the furnace lid and the tar addition rate G during molded coal production, it is possible to produce coke without changing the tar mass ratio F derived from the molded coal around the furnace lid, which indicates the degree of segregation when using the desired molded coal.

[0095] <Example 4: Estimation of segregation degree using volume and sphericity of molded coal> (Relationship between segregation degree, volume, and sphericity) Using the data on the segregation degree, volume (actual volume), and sphericity of briquettes a) to g) in Tables 1 and 2, the relationship equation (regression equation for the segregation degree, volume, and sphericity) described in the second embodiment was actually determined. As described above, multiple regression analysis was performed using linear regression by the least squares method, with the segregation degree determined in Example 1 as the objective variable and the actual volume and sphericity of the briquettes as explanatory variables. Using the regression coefficient, which is the slope of the obtained regression equation, a relationship equation between the actual volume and sphericity of the briquettes and the segregation degree around the furnace lid was derived.

[0096] In this case, the significance level was set to 5%, which is common in multiple regression analysis. When multiple regression analysis was performed assuming the intercept was significantly different from 0, the P value of the intercept exceeded the significance level, so multiple regression analysis was performed again assuming the intercept was not significantly different from 0 (i.e., intercept = 0), and the obtained results were used. The regression equation was derived as the following equation (4).

[0097] Degree of segregation around the furnace lid D = Actual volume of briquette coal × 0.0046 + sphericity of briquette coal × 1.1059 (4)

[0098] The above multiple regression analysis showed a significance F of 1.3 × 10 -6 The P values ​​for the actual volume of the briquettes and the sphericity of the briquettes were 0.009 and 1.1 × 10, respectively. -6 Since all of these were less than 0.05, each regression coefficient was determined to be significant.

[0099] The fact that there is no strong correlation between the actual volume of briquettes and the sphericity of briquettes, which were used as explanatory variables, was confirmed in advance by the following method. That is, in a graph showing the relationship between the actual volume of briquettes and the sphericity of briquettes, a regression equation was obtained by performing a simple linear regression using the least squares method from the plotted values, and the coefficient of determination (R 2 ) was calculated. The obtained coefficient of determination was used to calculate the tolerance (= 1-R 2 ) was confirmed to be greater than 0.1.

[0100] (Check the equation) Next, it was confirmed whether the above-obtained relational expression (4) could accurately estimate the degree of segregation. Specifically, a regression equation was obtained by using the degree of segregation of each briquette shown in Table 2 obtained in Example 1 as the objective variable and the degree of segregation obtained by expression (4) as the explanatory variable. Figure 5 shows the relationship between the degree of segregation around the furnace lid estimated from the actual volume and sphericity using the above expression (4) and the degree of segregation around the furnace lid obtained by the segregation test device 1 according to the procedure of Example 1. The coefficient of determination R 2 was 0.9986. Therefore, it was confirmed that the segregation degree estimated by the formula (4) was accurately estimated from the segregation degree obtained using the segregation test apparatus 1. Therefore, it was confirmed that the segregation degree of a desired molded coal can be accurately obtained using the relational expressions between the segregation degree, the volume, and the sphericity.

[0101] Example 5: Estimation of segregation degree using volume and aspect ratio of molded coal (Relationship between segregation degree, volume, and aspect ratio) For the molded coals a) to h) in Table 1, the aspect ratios were determined using an analytical application based on 3D CAD drawings of the molded coals created using a one-shot 3D shape measuring instrument (VR-3100 manufactured by Keyence Corporation), as in the case of sphericity. The aspect ratios were determined by dividing the minor axis length by the major axis length using the method described in the second embodiment. The aspect ratios of the molded coals a) to h) thus determined are shown in Table 3.

[0102] [Table 3]

[0103] For the briquettes a) to g), the relationship equations (regression equations relating the segregation degree to the volume and aspect ratio) described in the second embodiment were actually determined using the data on the segregation degree, volume (actual volume), and aspect ratio in Tables 1 to 3. As described above, multiple regression analysis was performed using linear regression by the least squares method, with the segregation degree determined in Example 1 as the objective variable and the actual volume and aspect ratio of the briquettes as explanatory variables. Using the regression coefficients, which are the slopes of the obtained regression equations, the relationship equations between the actual volume and aspect ratio of the briquettes and the segregation degree around the furnace lid were derived.

[0104] In this case, the significance level was set to 5%, which is common in multiple regression analysis. When multiple regression analysis was performed assuming the intercept was significantly different from 0, the P value of the intercept exceeded the significance level, so multiple regression analysis was performed again assuming the intercept was not significantly different from 0 (i.e., intercept = 0), and the obtained results were used. The regression equation was derived as the following equation (5).

[0105] Degree of segregation around the furnace lid D = Actual volume of briquette × 0.0101 + Aspect ratio of briquette × 0.9532 (5)

[0106] The above multiple regression analysis showed a significant F of 1.1 × 10 -5 The P values ​​for the actual volume of the briquette and the aspect ratio of the briquette were 0.001 and 1.5×10, respectively. -5 Since all of these were less than 0.05, each regression coefficient was determined to be significant.

[0107] The fact that there is no strong correlation between the actual volume of briquettes and the aspect ratio of briquettes, which were used as explanatory variables, was confirmed in advance by the following method. That is, in a graph showing the relationship between the actual volume of briquettes and the aspect ratio of briquettes, a regression equation was obtained by performing a simple linear regression using the least squares method from the plotted values, and the coefficient of determination (R 2 ) was calculated. The obtained coefficient of determination was used to calculate the tolerance (= 1-R 2 ) was confirmed to be greater than 0.1.

[0108] (Check the equation) Next, it was confirmed whether the above-obtained relational expression (5) could accurately estimate the degree of segregation. Specifically, a regression equation was obtained using the degree of segregation of each briquette shown in Table 2 obtained in Example 1 as the objective variable and the degree of segregation obtained by expression (5) as the explanatory variable. Figure 6 shows the relationship between the degree of segregation around the furnace lid estimated from the actual volume and aspect ratio using the above expression (5) and the degree of segregation around the furnace lid obtained by the segregation test device 1 according to the procedure of Example 1. The coefficient of determination R 2 The value was 0.9959. Therefore, it was confirmed that the segregation degree estimated by the formula (5) was an accurate estimate of the segregation degree obtained using the segregation test apparatus 1. Therefore, it was confirmed that the segregation degree of a desired molded coal can be obtained with high accuracy by using the relational expressions of the segregation degree, the volume, and the aspect ratio.

[0109] <Example 6: Estimation of segregation degree using the angle of repose of powdered coal> The relationship between the angle of repose of briquettes and the degree of segregation was determined using the method described in the third embodiment. The degree of segregation around the furnace lid was determined for each raw coal blended with briquettes d) at a blending ratio of 25% to powder coal with moisture contents of 4, 7, and 10% using the segregation tester 1. The angle of repose of the powder coal was also measured using the above-mentioned improved ASTM bulk density measuring device in a bulk density test in accordance with ASTM D 291-86. As described above, the angle of repose was measured as the angle between the slope and the bottom of the piled sample formed when 34 kg of powder coal sample was dropped from a height of 2 m.

[0110] Figure 7 shows the relationship between the degree of segregation of briquette coal d) obtained with the segregation test device 1 and the measured angle of repose. The angle of repose was smallest for powder coal with a moisture content of 4%, and increased in the order of 7% and 10%. The regression equation shown in Figure 7 was obtained by performing a regression analysis using linear regression by the least squares method. The obtained regression equation has a coefficient of determination R 2The angle of repose was 0.9152, confirming that the angle of repose can accurately describe the degree of segregation. Therefore, by determining the relationship between the angle of repose and the degree of segregation for the target briquette in advance, it is possible to estimate the degree of segregation around the furnace lid from the angle of repose of the powder coal. In addition, the estimated degree of segregation can be used to determine the appropriate overall briquette mass ratio when changing the powder coal. [Explanation of symbols]

[0111] 1 Segregation test equipment 2 Hopper 4 Sample box 6 Gate plate 8 Platform

Claims

1. A method for evaluating the segregation of briquettes around a coke oven furnace lid using a segregation test device, comprising: the segregation test apparatus includes a hopper that stores raw coal including powdered coal and briquettes, and a sample box into which the raw coal is charged from the hopper, the sample box having a rectangular parallelepiped shape corresponding to the vicinity of the furnace lid of the coke oven chamber, one end side of the sample box corresponding to the furnace lid position and the other end side of the sample box corresponding to the coal charging position of the hopper, and the sample box being divided into a plurality of sections in the length direction and height direction from the one end side to the other end side, The raw coal is dropped from the hopper and charged into the sample box; a furnace lid-periphery briquette mass ratio, which is the ratio of the briquette contained in the raw coal charged in the furnace lid-periphery section closest to the one end among the plurality of sections in the sample box, is determined; A method for evaluating the segregation of briquettes, comprising: calculating a segregation degree indicating the degree of segregation of the briquettes around the lid using the calculated briquettes mass ratio around the lid and an overall briquettes mass ratio, which is the blending ratio of the briquettes in the entire raw coal, according to the following formula (I): D = A / E (I) In formula (I), D is the degree of segregation, A is the mass ratio of briquettes around the furnace lid, and E is the total mass ratio of briquettes.

2. The segregation degree of the target briquette coal to be charged into a coke oven is determined by the briquette segregation evaluation method according to claim 1, a reference briquette used as a basis for determining the overall briquette mass ratio of the target briquette, the reference briquette having the same tar addition rate, which is the mass rate of tar added when producing the briquette, as the target briquette; and a briquette mass ratio around the furnace lid determined by the briquette segregation evaluation method for the reference briquette and the segregation degree of the target briquette, are substituted into formula (I) to determine the overall briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

3. A method for evaluating the segregation of briquettes around a coke oven furnace lid using a segregation test device, comprising: the segregation test apparatus includes a hopper that stores raw coal including powdered coal and briquettes, and a sample box into which the raw coal is charged from the hopper, the sample box having a rectangular parallelepiped shape corresponding to the vicinity of the furnace lid of the coke oven chamber, one end side of the sample box corresponding to the furnace lid position and the other end side of the sample box corresponding to the coal charging position of the hopper, and the sample box being divided into a plurality of sections in the length direction and height direction from the one end side to the other end side, The raw coal is dropped from the hopper and charged into the sample box; a furnace lid-periphery briquette mass ratio, which is the ratio of the briquette contained in the raw coal charged in the furnace lid-periphery section closest to the one end among the plurality of sections in the sample box, is determined; A method for evaluating the segregation of molded coal, characterized by using the determined molded coal mass ratio around the furnace lid and a tar addition rate, which is the mass ratio of tar added when producing the molded coal, to determine the mass ratio of tar derived from the molded coal around the furnace lid, which indicates the degree of segregation of the molded coal around the furnace lid, using the following formula (II): F = A × G (II) In formula (II), F is the mass ratio of tar derived from the briquettes around the furnace lid, A is the mass ratio of the briquettes around the furnace lid, and G is the tar addition rate.

4. The segregation degree of the target briquette coal to be charged into a coke oven is determined by the briquette segregation evaluation method according to claim 1, According to the method for evaluating segregation of briquettes according to claim 3, the tar mass ratio derived from the briquettes around the furnace lid, which is determined for a reference briquette used as a reference for determining the overall briquette mass ratio, which is the blending ratio of the target briquette in the raw coal, and the tar addition rate of the target briquette are substituted into the formula (II) to determine the briquette mass ratio around the furnace lid; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

5. 2. The method for evaluating segregation of molded coal according to claim 1, wherein the degree of segregation is determined by substituting the volume and sphericity determined for a molded coal of which segregation is to be evaluated into a relational expression obtained by multiple regression analysis of the degree of segregation determined for a plurality of types of molded coal by the method for evaluating segregation of molded coal and the volume and sphericity of the plurality of types of molded coal.

6. 2. The method for evaluating segregation of molded coal according to claim 1, wherein the degree of segregation is determined by substituting the volume and sphericity determined for a molded coal of which segregation is to be evaluated into a relational expression obtained by multiple regression analysis of the degree of segregation determined for a plurality of types of molded coal by the method for evaluating segregation of molded coal and the volume and aspect ratio of the plurality of types of molded coal.

7. 7. The method for evaluating the segregation of briquettes according to claim 5 or 6, further comprising the steps of: using the relational expression to determine the degree of segregation of the target briquettes to be charged into a coke oven; and determining the degree of segregation of a reference briquettes, which is used as a basis for determining the overall briquettes mass ratio of the target briquettes and has a tar addition rate, which is the mass ratio of tar added when producing the briquettes, in common with the target briquettes; the determined segregation degree of the standard briquette and the total briquette mass ratio when the standard briquette is charged into the coke oven are substituted into the formula (I) to determine the briquette mass ratio around the furnace lid of the standard briquette; the mass ratio of the briquettes around the furnace lid of the reference briquettes and the segregation degree of the target briquettes are substituted into the formula (I) to determine the total mass ratio of the briquettes; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

8. The segregation degree of the target briquette coal to be charged into a coke oven is determined by the briquette segregation evaluation method according to claim 5 or 6, According to the method for evaluating segregation of briquettes according to claim 3, the tar mass ratio derived from the briquettes around the furnace lid, which is determined for a reference briquette used as a reference for determining the overall briquette mass ratio, which is the blending ratio of the target briquette in the raw coal, and the tar addition rate of the target briquette are substituted into the formula (II) to determine the briquette mass ratio around the furnace lid; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

9. The angle of repose measured for several types of powder coal with different moisture contents, The degree of segregation obtained by the method for evaluating segregation of briquettes for a plurality of types of raw coals each combining the briquettes to be evaluated for segregation and the plurality of types of powder coal; 2. The method for evaluating segregation of briquettes according to claim 1, wherein the degree of segregation is determined by substituting the angle of repose of the fine coal to be combined with the briquettes whose segregation is to be evaluated into a relational expression obtained by regression analysis of the above formula.

10. Based on the method for evaluating segregation of briquettes according to claim 9, the degree of segregation of the target briquettes to be charged into a coke oven and the degree of segregation of a reference briquettes, which is used as a basis for determining the overall briquettes mass ratio of the target briquettes and has a tar addition rate, which is the mass ratio of tar added when producing the briquettes, in common with the target briquettes, are calculated using the relational expression; the determined segregation degree of the standard briquette and the total briquette mass ratio when the standard briquette is charged into the coke oven are substituted into the formula (I) to determine the briquette mass ratio around the furnace lid of the standard briquette; the mass ratio of the briquettes around the furnace lid of the reference briquettes and the segregation degree of the target briquettes are substituted into the formula (I) to determine the total mass ratio of the briquettes; A coke manufacturing method characterized by blending the target molded coal at the determined overall molded coal mass ratio and using raw coal blended with powdered coal having the angle of repose used when determining the degree of segregation of the target molded coal using the relationship formula.

11. The segregation degree of the target briquette coal to be charged into a coke oven is determined by the briquette segregation evaluation method according to claim 9, According to the method for evaluating segregation of briquettes according to claim 3, the tar mass ratio derived from the briquettes around the furnace lid, which is determined for a reference briquette used as a reference for determining the overall briquette mass ratio, which is the blending ratio of the target briquette in the raw coal, and the tar addition rate of the target briquette are substituted into the formula (II) to determine the briquette mass ratio around the furnace lid; the determined briquette mass ratio around the furnace lid and the segregation degree of the target briquette are substituted into the formula (I) to determine the total briquette mass ratio; A method for producing coke, characterized in that raw coal is used that is blended with the target briquette coal at the determined overall briquette coal mass ratio.

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