KR100643346B1 - A Blending Method of Coals for Making Coke - Google Patents

Abstract

The present invention relates to a method of mixing raw coal for preparing coke during humidity, and its object is ash, volatilization, maximum flow rate, total expansion, average reflectance when coal raw material is blended when the moisture of coal is controlled to 5.5-6.5%. By limiting compounding indices such as tissue equilibrium index, strength index, and total sulfur content to an appropriate range, the gas pressure at the time of producing coke is 200 mmH ₂ O or lower, and the cold strength (DI) and post-reaction strength (CRS) of the obtained coke are obtained. The aim is to provide a formulation control method for the raw coal in the humidity control to ensure that the quality is maintained within the quality standards.

In order to achieve the above object, the present invention adjusts the water content of coal to 5.5-6.5% and charges it into the coke oven to mix raw material coal for producing metallurgical coke. , Volatility: 24.0-28.0%, Maximum Flow Rate: 2.32-2.58 (log ddpm), Total Expansion: 83-107%, Average Reflectance: 0.9-1.02, Equilibrium Index: 1.2-1.8, Strength Index: 3.5-4.0, The summary relates to a method for blending raw coal for producing coke during humidity control, which is controlled to a total sulfur content: 0.7% or less.

Humidity, Coke, Mixing Method, Cold Strength, Post-Reaction Strength

Description

A Blending Method of Coals for Making Coke             

Figure 1 is a graph showing the gas pressure relationship during dry distillation according to the reduced coal coal moisture

Figure 2 is a graph for derivation of the blended coal mixture management range of the present invention

The present invention relates to a method of blending raw coal in the manufacture of metallurgical coke, and more particularly, to a method of blending raw coal in the case of drying the water of coal at about 6% and loading it into a coke oven.

In order to manufacture coke for blast furnaces, coals of 8 to 12 coals are generally blended. In order to manufacture this coal into coke suitable for blast furnace operation, the coal briquettes are formed as shown in Table 1 (metallurgical use in operation of more than 7% of water). Compounding range of the coal briquettes for coke production and coke quality). However, although the mixing range shown in Table 1 is possible in the operation in the range of 7% to 12% moisture in coal, when the water content in coal is less than 7%, coal is dried in coke oven even in mixed coal of the same properties. As shown in Fig. 1, the gas pressure may increase rapidly. This causes damage to the coke oven when the mixing is incorrect so that the gas pressure is increased rapidly. Coke furnaces for the manufacture of metallurgical coke usually have a life expectancy of 40 years or more, and the damage caused by excessive expansion of coal in dry distillation is fatal to furnace life.

Compound Index ASH VM LMF TD RM CBI SI TS DI CSR range 8.5> 26.0 ± 2.0 2.5 ± 0.3 95 ± 25 1.15 ± 0.1 1.5 ± 0.3 4.45 ± 0.3 0.7> 86.0 ≤ 65.0 ≤

[Wherein 1. ASH: ash content (%)

2. VM (Volatile Matter): Volatiles (%)

3.Log Maximum Fluidity (LMF): log ddpm

4.TD (Total Dilatation): Total Expansion (%)

5.Mean Reflectance of Vitrinite of Coal Texture (RM): Average Reflectance

6. Composition Balance Index (CBI): Organizational Parallel Index

7. SI (Strength Index): strength index

8.TS (Total Sulfur): Total Sulfur Content

9. DI (Drum Index): Cold Strength (%)

10. COK Strength after CO ₂ Reaction (%)]

On the other hand, the humidity of the coal is moistened to more than 6%, because when the moisture of the coal is less than 6%, dust is generated rapidly during transportation, which causes dust pollution.

In silo type coke which is generally used in the manufacture of metallurgical coke, when coal is charged into a coking furnace carbonization chamber, heat is supplied from a combustion chamber arranged on both sides of the carbonization chamber, and coal in the carbonization chamber is dried into coke. In the process of making coal from coke, the total drying time is usually 16 to 17 hours, and the maximum gas pressure occurs after 10 to 11 hours. This phenomenon of gas pressure shows an expansion phenomenon as the temperature shrinks at the initial stage of dry distillation during the heating of coal, and the temperature increases after a certain period of time, coinciding with the point when the expansion reaches its peak and the maximum gas pressure during distillation.

In general, when the moisture of the coal blended in the coke oven is reduced, the coke quality is improved, and the coke quality is determined by the Cold Index (Drum Index: DI) and the Coke Strength after CO ₂ Reaction (CSR).

Meanwhile, iron ore and coke are charged at the top of the blast furnace, and hot air at around 1250 ° C. is blown from the bottom to be discharged to the top of the blast furnace. At this time, the coke charged into the blast furnace acts as a breathable retaining material, a reducing material, and a heat source in the blast furnace. It does not provide breathability to the blast furnace, which leads to a decrease in productivity and problems such as aging of the rust.

Thus, the present inventors in the technology to charge the coke oven by controlling the moisture of the coal to about 6%, research and to find a raw material blending method of excellent quality of the coke obtained while preventing the coke oven damage during coke production The experiment was repeated and the present invention was proposed based on the results. The present invention provides ash, volatile matter, maximum flow rate, total expansion, and average reflectance when coal raw materials are mixed when the moisture of coal is controlled to 5.5-6.5%. By limiting the compounding index, such as the tissue equilibrium index, the strength index and the total sulfur content to an appropriate range, the gas pressure at the time of manufacturing coke shows a value of 200 mmH ₂ O or less, and the quality of the coke obtained is the cold strength (DI) as shown in Table 1 above. The purpose of the present invention is to provide a method of controlling the mixing of raw coal during humidity control to maintain the quality standards of CRS).

In order to achieve the above object, the present invention adjusts the water content of coal to 5.5-6.5% and charges it into the coke oven to mix raw material coal for producing metallurgical coke. , Volatility: 24.0-28.0%, Maximum Flow Rate: 2.32-2.58 (log ddpm), Total Expansion: 83-107%, Average Reflectance: 0.9-1.02, Equilibrium Index: 1.2-1.8, Strength Index: 3.5-4.0, It relates to a method of blending raw coal for the production of coke during humidity control, characterized in that it is controlled in the range of total sulfur content: 0.7% or less.

Hereinafter, the present invention will be described in detail.

The present invention relates to coal raw material blending when the water content of coal is controlled to 5.5-6.5%. Particularly, the cold coke obtained is designed to have a cold strength of 86.0 or more, and a post-reaction strength of 65.0 or more. It is designed to be 200mmH ₂ O or less.

For this blending design, we attempted to derive the scope of control of the coal mixture through multiple blending. That is, when the water content of coal is controlled to 5.5-6.5%, several experiments are repeated to derive a compounding range having a value of DI of 86.0 or more, CSR of 65.0 or more and IGP of 200 mmH ₂ O or less. As a result of repeating these experiments, it was found that DI, CSR, and IGP could satisfy the above ranges by properly controlling the values (range) of TD, LMF, RM, and SI in the compounding index.

Representative results of such experiments can be represented as shown in FIG. Figure 2 shows the change of DI, CSR and IGP according to the blending index such as TD, LMF, RM, SI, at the same time there is a section showing a value of DI more than 86.0, CSR more than 65.0, IGP less than 200mmH ₂ O It is.

The interval is as follows: LMF (maximum flow rate): 2.32-2.58 (log ddpm), TD (total expansion): 83-107%, RM (average reflectance): 0.9-1.02, SI (strength index): 3.5-4.0 Range. That is, according to such a compounding index, the objective of this invention can be achieved. Other compounding indices are limited to the ranges of ash content: 8.5% or less, volatility: 24.0-28.0%, tissue equilibrium index: 1.2-1.8, and total sulfur content: 0.7% or less. The blending index may be determined by the blending ratio of coal as is well known in the art.

As such, from Figure 2, it is possible to design a mixing range to satisfy the coke quality conditions and the gas pressure generated during dry distillation, which is shown in Table 2 below.

Compound Index ASH VM LMF TD RM CBI SI TS DI CSR range 8.5> 26.0 ± 2.0 2.32- 2.58 83- 107 0.9- 1.02 1.5 ± 0.3 3.5- 4.0 0.7> 86.0 ≤ 65.0 ≤

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

After mixing the blended coal as shown in Table 3 below, coke was prepared, and the cold strength (DI), the post-reaction strength (CRS), and the gas pressure generated in the dry gas were measured, and the results are shown in Table 3 below.

Comparative Example 1 Comparative Example 2 Inventive Example 3 Comparative Example 4 VM (%) 25.9 26.8 27.7 28.6 TD (%) 125 112 99 86 LMF (ddpm) 2.76 2.62 2.49 2.36 SI 4.31 4.07 3.84 3.60 CBI 1.34 1.38 1.42 1.47 RM 1.08 1.03 0.99 1.47 IM (%) 6.4 6.0 6.5 6.2 DI (%) 86.8 86.7 86.2 83.6 CSR (%) 73.4 71.5 69.0 59.7 IGP (mmH ₂ O) 283 246 123 111

As can be seen in Table 3, the gas pressure change according to the coal moisture of FIG. 1 is less than the gas pressure 200mmH ₂ 0 up to 7% of the coal moisture and the cold conditions of more than 85% and the strength after the reaction 65% or more of the quality conditions of metallurgical coke Judging from the above, the comparative example (1) and the comparative example (2) were satisfied with the coke quality condition, but the gas pressure was exceeded. In the comparative example (4), the gas pressure was satisfied with the condition, but the coke quality condition was I'm under. On the other hand, Inventive Example 3, which satisfy the conditions of the present invention satisfies the cold strength of 85% or higher and a reaction the strength of at least 65% of quality standards of the coke for metallurgy, the gas pressure was also 200mmH ₂ O or less 123mmH ₂ O.

Example 2

After mixing the blended coal as shown in Table 4 below, coke was prepared, and the cold strength (DI), the post-reaction strength (CRS), and the generated gas pressure in the dry gas were measured, and the results are shown in Table 4 below.

Comparative Example a Inventive Example b Inventive Example c Comparative example d VM (%) 25.1 26.3 27.4 28.5 TD (%) 113 98 83 68 LMF (ddpm) 2.51 2.48 2.45 2.42 SI 4.34 4.02 3.70 3.38 CBI 1.51 1.61 1.72 1.82 RM 1.09 1.02 0.97 0.91 IM 6.7 6.4 6.2 6.0 DI 88.1 86.0 86.2 84.7 CSR 72.4 66.5 67.1 64.7 IGP 210 106 142 129

As can be seen in Table 4, Inventive Example (b, c) satisfying the 6% of the range of the coarse humic coal blend of the present invention, while maintaining the coke quality conditions and the limit gas pressure during dry distillation, Comparative Examples ( a, d) does not satisfy gas pressure or coke quality conditions.

In other words, Comparative Example (a) is a coal blend belonging to the blending management standard when operating in the water content of coal from 7% to 10%, and the total expansion, strength index, and average reflectance is higher than the blending standard of the present invention. The quality of the coke produced as can be secured sufficiently, but the high gas pressure during dry distillation will give an excessive load on the coke oven. In addition, Comparative Example (d) has a low pre-expansion, high strength index and high tissue equilibrium index, and the gas pressure satisfies 200 mmH ₂ O or less, but falls short of the coke quality of cold strength and post-reaction strength.

By analyzing the results of the above embodiment, in accordance with the formulation management criteria of Table 2, if you manage the blending properties of the coal blend at 6% moisture humidity, not only the desired coke quality can be obtained, but also the damage caused by the coke caused by excessive coal expansion is not shown. Could prevent.

 As described above, when the moisture of the blended coal is moistened to 6%, the blended range of the present invention not only satisfies the conventional coke quality level, but also operates the coke at a gas pressure level of 7% to 10% of water in coal. It is possible to prevent excessive pressure load on the coke oven wall which is easy to occur during operation.

Currently, the coke oven is aiming for a life of more than 40 years, but if the coke oven is seriously damaged due to the mismanagement of raw coal, the plant must be closed regardless of the service life to date. Coke oven has been closed

Claims (1)

In the mixing method of raw coal to adjust the water content of coal to 5.5-6.5% and charge it into the coke oven to produce metallurgical coke, when mixing the raw materials, ash content: 8.5% or less, volatile content: 24.0-28.0%, highest Flow rate: 2.32-2.58 (log ddpm), Total expansion: 83-107%, Average reflectivity: 0.9-1.02, Equilibrium index: 1.2-1.8, Strength index: 3.5-4.0, Total sulfur content: 0.7% or less Blending method of raw coal for coke production during humidity control, characterized in that controlled by

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