Method for producing coal cake for coke production

Abstract

To propose a method for producing a coal cake for coke production that can prevent an upper part of the coal cake from collapsing even when molding the coal cake into blocks by the stamp charging technique.SOLUTION: The present invention provides a method for producing a coal cake for coke production, which molds a coal cake used in coke production by the stamp charging technique. During the molding of the coal cake, molding energy at any height of the coal cake should be equal to or more than the energy Et (kJ / t) needed to achieve a target density.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a coal cake for coke production, in which a coal cake to be used in coke production is molded by a stamp charge method. [Background technology]

[0002] As high-quality, highly coking coal for use in coke production is becoming scarce, there is a need to ensure strength even when using inferior coal. One technique for improving strength is to increase the bulk density of the coal charged into a coke oven, and one example is the stamp charge method (Patent Document 1).

[0003] In the stamp charge method disclosed in Patent Document 1, a mixture of powdered coal and briquettes is stamped from above with a stamper to form a block-shaped coal cake with high bulk density. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-44126 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the strength of the block-shaped coal cake formed by the stamp charge method varies depending on the location, and the upper part of the coal cake is not crushed by its own weight from above, so its bulk density is low and its strength is likely to be low. Therefore, when a coal cake is stamped a certain number of times to form a block shape, the upper part of the coal cake may collapse due to insufficient strength. In such a case, the coal cake with the collapsed upper part cannot be charged into the carbonization chamber of the coke oven, and the coal cake cannot be carbonized to produce coke.

[0006] An object of the present invention is to solve the above problems and to propose a method for manufacturing a coal cake for coke production, which can prevent the upper part of the coal cake from collapsing even when the coal cake is molded into a block shape by the stamp charge method. [Means for solving the problem]

[0007] To prevent the coal cake from collapsing, the density of the coal cake formed by the stamp charge method is 1100 kg / m 3 Therefore, in order to solve the above-mentioned problems, the present invention has conducted extensive research into the causes of the coal cake collapsing from the top, and has obtained the following findings. 1) When the height of the coal cake increases during stamping, the density of the lower part of the coal cake increases due to the weight of the coal above and the impact of stamping. On the other hand, the density increase of the upper part of the coal cake is only due to the stamping directly above, so the density increase is small and the coal cake strength is insufficient. 2) The density of the resulting coal cake varies greatly depending on the brand, properties, particle size, etc. of the coal, even when the same stamping energy is applied.

[0008] The present invention was made based on the above findings, and its gist is as follows: That is, the method for producing a coal cake for coke production of the present invention is a method for producing a coal cake for coke production, in which a coal cake to be used in coke production is molded by a stamp charge method, characterized in that during molding of the coal cake, at any height of the coal cake, the molding energy is equal to or greater than the energy Et (kJ / t) required to achieve a target density.

[0009] In the method for producing coal cake for coke production according to the present invention configured as described above, (1) The above Et is calculated for each coal based on the stamping energy E (kJ / t) and coal cake density ρ (kg / m 3 ) and be set based on a correlation with (2) The Et satisfies the following formula (1) at any height of the coal cake: Et≦Eg+Es (1) Where, Eg: Energy generated by the load when charging coal at height h (kJ / t) Es: Stamping energy during charging at height h (kJ / t); (3) The Es is kept constant at any height of the coal cake, and the coal charging speed is slowed as the height of the coal cake increases. This is considered to be a more preferable solution. [Effects of the Invention]

[0010] According to the method for producing a coal cake for coke production of the present invention, the energy required for shaping is equal to or greater than the energy Et (kJ / t) required to achieve a target density at any height of the coal cake, thereby preventing the coal cake from collapsing from the top. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an embodiment of a conventionally known coke oven that uses the coal cake of the present invention. [Figure 2] FIG. 1 is a diagram illustrating an embodiment of stamp charge equipment used in producing a coal cake according to the present invention. [Figure 3] 1 is a graph showing an example of the relationship between stamping energy and coal cake density to explain Et in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes in detail the embodiments of the present invention. Note that the following embodiments are intended to exemplify devices and methods for embodying the technical concept of the present invention, and are not intended to limit the configuration to that described below. In other words, the technical concept of the present invention can be modified in various ways within the technical scope defined in the claims.

[0013] <Coke oven using the coal cake of the present invention> FIG. 1 is a diagram illustrating one embodiment of a conventionally known coke oven that uses the coal cake of the present invention. In the example shown in FIG. 1, the coke oven 1 is a structure (a furnace battery) in which coke chambers 2 into which coal cakes are charged and combustion chambers 3 that heat the coke chambers 2 are alternately arranged. In the coke chambers 2, coal is steam-roasted (carbonized) to produce coke. The produced coke is removed from the coke chambers 2 by opening detachable furnace covers 4 attached to the kiln openings at the front and rear ends of the coke chambers 2 and pushing the coke horizontally using a push-out ram (not shown).

[0014] A heat regenerator 5 is provided integrally at the bottom of the combustion chamber 3, and the combustion chamber 3 and heat regenerator 5 combust fuel gas 6 with air 9 and discharge the combustion exhaust gas 7 outside the coke oven 1, thereby heating the adjacent carbonization chamber 2 to a temperature at which coal can be carbonized. The coke oven 1 configured as described above has a high coal processing capacity, good thermal efficiency, and can produce high-strength coke.

[0015] In the coke oven 1 having the configuration shown in Fig. 1, the combustion chamber 3 and the regenerator 5 are divided into two longitudinal sections, a combustion side and a withdrawal side, by a partition wall 8, as shown in Fig. 1, and the fuel gas 6 and the burned combustion gas are circulated as shown by the arrows in Fig. 1 from (combustion side of regenerator 5) → (combustion side of combustion chamber 3) → (withdrawal side of combustion chamber 3) → (withdrawal side of regenerator 5), heating the adjacent coke oven 2 to a temperature for carbonizing coal, for example, about 1100°C. After this state continues for about 20 to 30 minutes, the gas flow is reversed to switch between combustion and exhaust, and the combustion side and the withdrawal side are alternately heated and repeated.

[0016] <Method of manufacturing coal cake for coke production according to the present invention> FIG. 2 is a diagram illustrating one embodiment of the stamp charge equipment used to produce a coal cake according to the present invention. In the example shown in FIG. 2, multiple stampers 22 are provided on top of a coal extruder 21. Coal 23 is charged into the coal extruder 21 from above via a hopper 25, and the stamper 22 is moved up and down to stamp the coal 23 from above and form a coal cake 24. The front end of the coal extruder 21 is composed of a movable door 21a, and the rear end is composed of a rear wall 21b. The movable door 21a and the rear wall 21b can be set in a predetermined position to form a stamping box. Therefore, by stamping the coal 23 with the stamper 22, the charged coal 23 can be molded into a predetermined block shape to obtain a coal cake 24. The molded coal cake 24 is set in the carbonization chamber 2 of the coke oven 1 by pushing it with the rear wall 21b at the rear end while the movable door 21a at the front end is open. The coal cake 24 set in the carbonization chamber 2 is then carbonized in the carbonization chamber 2.

[0017] The method for producing a coal cake for coke production according to the present invention is characterized in that, during molding of the coal cake 24 in the above-described coal-loading extruder 21, the molding energy is equal to or greater than the energy Et (kJ / t) required to achieve the target density at any height of the coal cake.

[0018] Here, Et (kJ / t) is the target density (for example, 1100 kg / m 3 ) is the energy required to achieve the desired density. Even when the same stamping energy is applied to the coal, the density of the coal cake formed by the stamp charge method varies greatly depending on the brand, properties, particle size, etc. of the raw coal. Therefore, it is preferable to investigate in advance the correlation between the stamping energy E and the coal cake density ρ through offline testing and determine Et for each raw material. Suitable actual examples of Et will be explained in the following examples based on Table 1 and Figure 3.

[0019] In addition, in a preferred embodiment of the method for producing a coal cake for coke production of the present invention, Et may satisfy the following formula (1) at any height of the coal cake: Et≦Eg+Es (1) Where, Eg: Energy generated by the load when charging coal at height h (kJ / t) Es: Stamping energy during charging at height h (kJ / t);

[0020] Here, the energy Eg (kJ / t) generated by the load when charging coal at height h is defined as Eg = g × l (g: gravitational acceleration, l: distance the coal falls). For example, if coal is supplied from a hopper at a height of 7 m to create a coal cake that is 6 m high, Eg is calculated as Eg = g × l, assuming that the energy of the coal falling is converted into compression of the coal cake.

[0021] Furthermore, the stamping energy Es (kJ / t) during charging at a height h is defined as Es = (stamping speed (times / sec)) × (pressure energy per time by the stamper (J / time)) / (charging speed (t / sec)). In order to increase productivity while preventing the coal cake from collapsing, it is preferable to adjust the stamping energy Es during charging so that it increases as the height of the coal cake increases. Es can be increased by increasing the stamping speed, increasing the weight of the stamper to increase the pressurizing energy, reducing the amount of coal charged, or a combination of these methods. [Example]

[0022] As an example, coal with a -3mm particle ratio of 90% and a moisture content of 10% was used to investigate the coal cake density ρ when the stamping energy E was changed in the range of 300 to 700 (kJ / t). The results are shown in Table 1 and Figure 3 below as the relationship between stamping energy and coal cake density in offline coal tests. From the graph in Figure 3, it can be seen that in the case of this coal, for example, 1100 (kg / cm 3The target stamping energy Et to obtain the target density of 100 kJ / t is Et=547 (kJ / t).

[0023] As shown in Figure 3, for the above coal, when the coal cake density is y and the stamping energy is x, y = 585.5x 0.1 Here, the coefficient 585.5 and the exponent 0.1 take different values ​​for each type of coal. Therefore, if the coefficient is a and the exponent is b, the relationship between coal cake density and stamping energy can be expressed as y=ax, regardless of the type of coal. b It can be shown that:

[0024] [Table 1]

[0025] Using the above coal, coal cakes of Comparative Example 1, Example 1, and Example 2 were molded according to the stamp charge method, with the stamping speed (times / second), stamper pressure energy (kJ / time), and charging speed (t / second) varied. The presence or absence of collapse of the upper layer of the coal cake when charged into the carbonization chamber of a coke oven was then investigated. The shape of the coal cake was 0.43 m wide x 15.43 m long x 6 m high, and the height of the hopper into which the coal was charged was 7 m. The various molding conditions and molding results for Comparative Example 1, Example 1, and Example 2 are shown below in Tables 2, 3, and 4.

[0026] [Table 2]

[0027] [Table 3]

[0028] [Table 4]

[0029] In Comparative Example 1, collapse of the coal cake occurred from the upper layer. This is thought to be because Es+Eg was less than the target Et=547 (kJ / t) at heights of 3 m or more. On the other hand, in Examples 1 and 2, where Es+Eg was equal to or greater than the target Et=547 (kJ / t) over the entire height of the coal cake, no collapse of the coal cake was observed from the upper layer.

[0030] From the above, it was found that, during molding of the coal cake, at any height of the coal cake, if the molding energy is equal to or greater than the energy Et (kJ / t) required to achieve the target density, a coal cake can be obtained that does not collapse in the upper layer of the coal cake.

[0031] Furthermore, comparing Example 1 and Example 2, the pressing energy of the stamper was 55.0 (kJ / cycle) in Example 1 and 50.0 (kJ / cycle) in Example 2. Furthermore, the time required for coal charging (integral value of coal charging speed) was shorter in Example 2 than in Example 1. Therefore, it was found that Example 2 has better productivity than Example 1 and is preferable. [Industrial Applicability]

[0032] According to the coke manufacturing method of the present invention, the energy required for molding the coal cake is equal to or greater than the energy Et (kJ / t) required to achieve the target density at any height of the coal cake during molding, which prevents the coal cake from collapsing from the top, and is therefore industrially useful. [Explanation of symbols]

[0033] 1. Coke oven 2. Carbonization chamber 21 Coal extrusion machine 21a Movable door at the front end 21b Rear wall at rear end 22 Stamper 23 Coal 24 Coal Cake 25 Hopper

Claims

1. In a method for manufacturing a coal cake for coke production, the coal cake to be used for coke production is molded by a stamp charge method, During molding of the coal cake, at any height of the coal cake, the molding energy is equal to or greater than the energy Et (kJ / t) required to achieve the target density; The Et satisfies the following formula (1) at any height of the coal cake: Et≦Eg+Es (1) Where, Eg: Energy generated by the load when charging coal at height h (kJ / t) Es: Stamping energy during charging at height h (kJ / t); A method for producing coal cake for coke production, comprising:

2. The Et is calculated for each coal based on the stamping energy E (kJ / t) and coal cake density ρ (kg / m ３ 2. The method for producing a coal cake for coke production according to claim 1, wherein the temperature is set based on a correlation between the temperature and the amount of the coal cake.

3. 3. The method for producing a coal cake for coke production according to claim 1 or 2, wherein Es is kept constant at any height of the coal cake, and the coal charging speed is slowed as the height of the coal cake increases.

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