KR20170073012A - Method for manufacturing coke - Google Patents

Abstract

The present invention relates to a method of manufacturing a coke which improves the strength of coke by forming a part of coke during mixing. The method for producing coke according to one embodiment of the present invention is a method for producing coke for blast furnace, To prepare a compounding carbon; Molding a part of the blend to prepare a blast furnace; Mixing the unshaped blend of the blend with the blended blend to prepare mixed blend; Charging the mixed carbon into a coke oven; And carburizing the mixed coal charged into the coke oven.

Description

[0001] METHOD FOR MANUFACTURING COKE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coke making method, and more particularly, to a coke making method in which a part of coke is blended to improve coke strength.

Generally, steel mills produce molten iron by the blast furnace method. In order to produce molten iron in the blast furnace, sinter ore and coke are prepared. In the blast furnace, stable coke is preferred in terms of stability and productivity. Coke oven is also used to produce coke with high strength. . Especially in recent years, as the size of the blast furnace has increased, the residence time of the coke in the blast furnace has increased, and the need for coke having a higher strength than that which has been maintained has increased.

In general, the coke quality has a correlation with the compounding index of the blend. The highest correlation index is LMF (Log value of maximum fluidity) and Rm (coal refinement index), which is the maximum reflectance value of bimetallic structure in coal tissue. The higher the combination index The quality of the coal is excellent and the price is high.

In order to improve the coke strength, the use of high-quality raw coke with high coke strength will increase the cost of raw materials. Therefore, it is necessary to mix the high-grade cokes and the low-grade cokes appropriately to improve the coke strength, Technology is required. Therefore, the blending technology is a method of improving the quality of coke produced by appropriately mixing low-quality coal. In addition, various methods such as pretreatment, digestion and digestion methods for improving the quality of coke, and techniques for utilizing additives are developed and utilized have.

Among them, there is a method of improving the coke strength by increasing the charging density in the carbonaceous chamber through molding, which is a pretreatment process of coal. Although the molding process is a technique for improving the charging density of coal regardless of the type of coal, the effect of molding may vary depending on the type of coal.

Therefore, the present invention proposes a method of molding coal at a certain pressure by improving the coke strength. In particular, the present invention finds a coal having a great effect on the improvement of coke strength according to a specific coal, We want to derive a formulation method for economical coke quality improvement in compliance with management standards.

Japanese Laid-Open Patent Application No. 2015-199791 (Nov. 12, 2015)

The present invention relates to a coke oven which is formed by molding only a part of coke in the mixing of raw coke and then mixing the coke with raw coke of a different form so that the general coke oven charging device provided in the coke oven is used as it is, ≪ / RTI >

A method of manufacturing a coke for a blast furnace according to an embodiment of the present invention is a method for manufacturing a blast furnace coke, comprising the steps of preparing blended coal by blending different types of coking coal; Molding a part of the blend to prepare a blast furnace; Mixing the unshaped blend of the blend with the blended blend to prepare mixed blend; Charging the mixed carbon into a coke oven; And carburizing the mixed coal charged into the coke oven.

In the step of preparing the compounded carbon, the LMF of the compounded carbon is preferably at least 3.465, and Rm is preferably at least 0.7525.

Here, LMF is the logarithm of the maximum fluidity as the fluidity index, and Rm is the coalification index, which is the Max. Reflectance value.

In the step of preparing the compounded carbon, the blended carbon preferably contains a first coking coal having an LMF of 3.465 or less and an Rm of 0.7525 or more, a second coking coal having an LMF of at least 3.465 and a Rm of 0.7525 or less.

In particular, it is preferable that Rm of the first coking coal is not less than 0.803, and LMF of the second coking coal is not less than 4.54 in the step of preparing the compounded carbon.

In the step of preparing the mixed carbon, the weight ratio of the molded carbon in the mixed carbon is preferably 20% or more.

The step of charging the mixed carbon into the coke oven is characterized by using the charging apparatus of the coke oven as it is.

According to the embodiment of the present invention, there is an effect that the coke strength can be improved by improving the blending standard of the blended carbon and molding a part of the blended carbon while using the low-grade bull which conventionally causes the lowering of the coke strength.

In addition, since only a part of the blend is molded, high-quality coke can be produced while using low-grade seeds within the range of operating standards managed in the conventional coke making process. Therefore, it is possible to improve the competitiveness of the coke- Reduction is expected.

1 is a flowchart illustrating a method of manufacturing coke according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know.

First, in general, the method used for producing coke is such that raw coke is crushed so as to achieve uniform mixing and charging density in the carbonizing chamber, and then the particle size and the compounding ratio of the coke are adjusted to prepare a blend, Is charged into the carbonization chamber from the charge car installed on the carbonization furnace, and then the carbonization is carried out at high temperature in an oxygen-free state to produce the coke.

However, in the case of low-grade coal, since the strength of the produced coke is reduced in the case of manufacturing under normal operating conditions, in order to increase the density of the coal to be charged instead of the general method of discharging coal into the carbonization chamber by gravity from the top In the forming mold, coal is molded into a carbonizing chamber by molding or stamping (Stamp). The coke produced by this method has a higher density of coal to be charged into the carbonization chamber than the conventional method, so that the quality of coke produced is improved. However, since the charging method itself differs, it is expensive compared to the conventional methods such as the introduction of new equipment and the operating cost. Therefore, instead of the method of molding the entire coal to be charged, only a part of the coal to be blended is molded in the mold, .

Accordingly, the main technical idea of the present invention is a method of manufacturing a coke by forming a part of compounded coal while compounding specific coal among compounded coal used for producing coke for metallurgy.

There are various kinds of coal, and since it has different physical properties such as fluidity, degree of coalization, volatile content, and constituted tissue content depending on the type of coal, degree of contribution to the coke strength depends on the type of coal. Therefore, the improvement of the coke strength can be different in a specific blend, and a blending technique capable of maximizing the coal molding effect is applied to manufacture the coke.

1 is a flowchart illustrating a method of manufacturing coke according to an embodiment of the present invention.

As shown in FIG. 1, a method of manufacturing a coke according to an embodiment of the present invention is a method of manufacturing a coke for a blast furnace by using a conventional coke making facility and its operating conditions as it is, Preparing a shot; Molding a part of the blend to prepare a blast furnace; Mixing the unshaped blend of the blend with the blended blend to prepare mixed blend; Charging the mixed carbon into a coke oven; And carburizing the mixed coal charged into the coke oven.

The step of preparing the compounded carbon is a step of blending different types of cyanogen into appropriate proportions to form a compounded carbon having a desired level of quality. The LMF of the compounded carbon in the present embodiment is at least 3.465, 0.7525 or more. Here, LMF is the logarithm of the maximum fluidity as the fluidity index, and Rm is the coalification index, which is the Max. Reflectance value.

The LMF as a fluidity index and the coalification index Rm are physical properties showing the quality of coal. In order to adjust the physical property values to a desired level, the first coking coal and the LMF having an LMF of 3.465 or less and Rm of 0.7525 or more are 3.465 or more, And a second coking coal having a Rm of 0.7525 or less is blended to prepare a blend. Preferably, Rm of the first coking coal is 0.803 or more, and the LMF of the second coking coal is preferably 4.54 or more.

The reasons for limiting the numerical values of LMF and Rm of the first coking coal and the second coking coal will be explained later on the basis of the comparative example and the example.

The step of preparing the briquettes is to briquetize a part of the blend, and the briquetting method may be implemented in various ways. For example, it is possible to form the molding coal corresponding to the shape of the molding space by supplying molding blend to a molding frame, molding the molding with stamps or stamps, or supplying the blended molding material between a pair of rollers formed with molding spaces will be.

The step of preparing the mixed carbon is a step of mixing the unburnt carbon blend and the molded carbon blend to prepare mixed carbon blended with the blended carbon blend.

At this time, it is preferable that the ratio of the briquettes is 20% or more of the mixed carbon in weight ratio. Preferably, the proportion of the blasted carbon is preferably 20% or more and 50% or less of the mixed carbon by weight ratio. The reason for this is that if the ratio of the blasted carbons is less than 20%, the effect of improving the strength due to blending of the blasted carbons can not be expected. If the blasted blend ratio exceeds 50%, the proportion of blasted carbons increases, This is because there is a problem that a new charging device must be provided.

In the step of charging the mixed carbon into the coke oven, the prepared mixed carbon is charged into the carbonization chamber of the coke oven by using the coke charging apparatus provided in a general coke manufacturing facility as it is.

The step of carburizing the mixed carbon is a step of carbonizing the mixed carbon charged in the carbonization chamber of the coke oven in a high-temperature atmosphere without oxygen.

The step of charging the mixed carbon into the coke oven and the step of carbonizing the mixed carbon are carried out while applying the operating control standard for manufacturing the coke in a general coke oven.

Next, the reason for limiting the numerical values of the LMF and Rm of the blend is described based on the results of the test to see the advantages of the coke making method according to the embodiment of the present invention.

However, since the test in the actual coke oven is not easy, the test furnace which can be charged up to 30 kg was used.

Coke-producing formulation Tan 8% so as to have a certain charge density in operating condition and the back is less than 3mm particle size to similarly apply possible to ensure that 85% was thoroughly mixed according to the compounding ratio, 750kg in a dry base / m ³ moisture content is And then a certain amount of the mixture was charged in a pair of forming rollers according to the molding ratio, and the mixture was uniformly mixed with the unblended blend and then charged.

The forming roll runs at a linear pressure of 20 KN / cm and is made up of a cylinder consisting of a number of roll cups of 64.5 mm X 25.4 mm X 19.1 mm in size.

In the coke test, a heater was installed so that heat was transferred from both walls in the same manner as a commercial coke oven. After the compounding coals were charged into a test furnace heated to 650 ° C, the heating wall temperature was raised to 1080 ° C at a heating rate of 2 ° C / min. When the oven center temperature reached 1000 ° C, , And the extruded glow coke was extinguished in a fire extinguishing facility in a nitrogen atmosphere.

On the other hand, the cold strength (DI) measurement method and the hot strength (CSR) measurement method for evaluating the coke strength are as follows.

The cooled coke-like coke samples are mixed in an appropriate ratio by particle size, and then 10 kg is weighed into a drum tester and rotated 150 times. After recovering the sample, the sample was sieved to 15 mm or more, and the weight ratio was measured, and the cold strength (DI) was obtained as shown in the following formula 1.

[Formula 1]

Cold Strength (DI) = (15 mm phase weight / sample weight) X 100

The sample was poured into a reactive sample preparation system, and the sample was poured into a reaction furnace with a weight of 200 g through a screen (19 mm to 21 mm, reacted with CO ₂ at a high temperature (1100 ° C.) for 120 minutes, The sample was weighed at 600 rpm in the I-type stiffness machine, and the weight of 10 mm was obtained. The weight was calculated as a percentage of the weight after the reaction, and the hot strength (CSR) was obtained as shown in the following formula 2.

[Formula 2]

Hot Strength (CSR) = (10 mm phase weight / sample weight) X 100

Next, as shown in [Table 1], M coal (first coking coal) having a relatively high fluidity index (LMF) of 4 or more according to the characteristics of coal, And Comparative Example 1, Comparative Example 2, and Comparative Example 3 were obtained by blending R coals (second coking coal) having a relatively high maximum reflectance (Rm) of 0.77 or so relative to the base coal X coal at a ratio of 1: Example 1 and Example 2 were formulated. At this time, 0.3% level of oil was mixed with the amount of coking coal for the blending.

In Comparative Example 1 and Comparative Example 2, the blended blend was charged into the upper portion of the blast furnace by gravity in a coke oven as in the actual coke oven, and in Examples 1 and 2, % Were molded using molding roll equipment, and then mixed with the remaining 80% of blended carbon. The blended carbon was charged to the upper part by gravity in the coke test furnace. After completion of charging, Comparative Example 1, Comparative Example 2, Example 1 and Example 2 were subjected to the production of coke according to a standard production management standard for coke production, followed by measurement of cold strength (DI) and hot strength (CSR) Are shown in Table 2.

Tan
Industrial analysis Elemental analysis Analysis of Coal Properties Ash FC VM C H N LMF Rm X coal 10.11 55.10 32.69 81.56 4.97 1.47 2.39 0.803 M Coal 8.58 51.50 38.11 84.92 4.73 1.58 4.54 0.702 R Coal 8.60 55.29 34.49 86.51 5.16 2.33 3.86 0.773

division Comparative Example 1 Example 1 Comparative Example 2 Example 2 Base (%) X coal 50 50 50 50 R / M ratio (%)
R Coal 50 50 0 0 M Coal 0 0 50 50 Molding Ratio (%) 0 20 0 20 oil(%) 0.3 0.3 0.3 0.3 Compounding index
LMF 3.125 3.465 Rm 0.788 0.7525 Coke strength
DI 66.88 67.28 71.00 74.36 CSR 27.55 27.30 26.72 35.55

As shown in Table 2, in the case of Comparative Example 1 and Example 1 in which 50% of R coal was blended, the DI was increased by 0.4 and the CSR was decreased by 0.25 at 20% molding. However, in the case of Comparative Example 2 and Example 2 in which 50% of M coal was blended instead of R coal, DI was 3.36 and CSR was 8.83.

In addition, when the coke is produced only from the crushed mixed carbon as in the conventional method without molding as in Comparative Example 1 and Comparative Example 2, when the coal M is added to the coal X, the DI is 4.12 Coke could be obtained, but rather CSR was lowered to 0.83 coke.

However, in the case of Example 2 in which 20% of the blend coal was molded, it was found that both DI and CSR were increased, so that it was possible to produce a coke having high CSR as well as DI in blending M coal with R coal I could.

As shown in the above test results, it has been shown that the strength of the coke can be improved by mixing and mixing a part of the blend, and that the coal molding effect differs depending on the type of coal, I could. For example, when R coal was used for mixing, there was almost no improvement in the strength of coke, and it was found that the improvement in coke strength was significantly exhibited by molding M coal. In addition, it has been shown that the coke strength can be improved through the molding of the coal, which was previously excluded when blending to open the coke strength.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

Claims (6)

A method for producing a blast furnace coke,
Preparing a blended coal by blending different types of coking coal;
Molding a part of the blend to prepare a blast furnace;
Mixing the unshaped blend of the blend with the blended blend to prepare mixed blend;
Charging the mixed carbon into a coke oven;
And carburizing the mixed coal charged in the coke oven.
The method according to claim 1,
In the step of preparing the compounded carbon,
Wherein the blend has an LMF of at least 3.465 and a Rm of at least 0.7525.
Here, LMF is the logarithm of the maximum fluidity as the fluidity index, and Rm is the coalification index, which is the Max. Reflectance value.
The method of claim 2,
In the step of preparing the compounded carbon,
Wherein the blended coal comprises a first coking coal having an LMF of not more than 3.465 and an Rm of not less than 0.7525, and a second coking coal having an LMF of not less than 3.465 and a Rm of not more than 0.7525.
The method of claim 3,
In the step of preparing the compounded carbon,
Wherein Rm of the first coking coal is 0.803 or more, and LMF of the second coking coal is 4.54 or more.
The method according to claim 1,
In the step of preparing the mixed carbon,
Wherein the weight ratio of the molded coal in the mixed coal is 20% or more.
The method according to claim 1,
Wherein the step of charging the mixed carbon into the coke oven uses the charging apparatus of the coke oven as it is.

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