KR20120133104A - Mixing method of coal for making cokes - Google Patents

Abstract

PURPOSE: A coal blending method for manufacturing cokes is provided to stabilize a furnace process by blending different kinds of coal while managing the volatile matter and ash contents of coal according to stack height. CONSTITUTION: A coal blending method for manufacturing cokes is characterized in that coal comprising a plurality of kinds of coal is blended according to stack height while managing the blending index to satisfy predetermined ranges of volatile matter content and ash content. The blending index is set by surveying the gain size of coal according to stack height and the variation of physical properties according to the grain size and calculating weight average values of volatile matter content and ash content based on the physical property variation. [Reference numerals] (AA) Coal type A; (BB) Coal type B; (CC) Coal type C; (DD) Grain size(mm); (EE) Stack height(m)

Description

Mixing method of coal for making cokes

The present invention relates to a raw coal blending method for coke production, and more particularly to a raw coal blending method for coke production for improving coke quality.

Coke is a fuel used as a heat source for blast furnaces and also serves as a reducing agent for reducing iron ore. Coke is produced by heating and coal drying coal in a coke oven plant.

Coal making coal has a coking property that can be caking well during dry distillation, so bituminous coal is used as a raw material. Coal used in the coke production is called raw coal separately from general fuels.

It is an object of the present invention to provide a method for blending coking coal for preparing coke, which manages a blending index based on volatile matter and ash content in order to improve coke quality by preparing a plurality of coal species.

According to a feature of the present invention for achieving the object as described above, the present invention is formulated by the stacking height when mixing the raw coal consisting of a plurality of coal coal species, the volatile content, ash content of the coal coal species so as to satisfy the set range Manage the blending index.

The blending index is a step of investigating the particle size of each raw coal according to the pile height, the step of investigating the change in physical properties according to the particle size, and calculating the weighted average value of the volatile content and ash content of each raw coal based on the investigated physical property change It is derived through the steps.

The weighted average value is a compounding ratio for each pile type by which the volatile matter content and the ash content satisfy a setting range.

The setting range of the volatile matter content is 24 to 26%, and the setting range of the ash content is more than 0 and 11.5% or less.

The raw coal blending method for coke production of the present invention is to mix the coal coal species by managing the volatile content, ash content according to the appropriate height during the mixing of the raw coal composed of a plurality of coal coal species, so that the coke quality improvement and maintenance can be achieved to stabilize the blast furnace process It can be effective.

1 is a graph showing the particle size change according to the stacking height of coal coal species (A coal species, B coal species, C coal species).
Figure 2 is a graph showing the volatile content according to the loading height of coal coal species (A coal species, B coal species, C coal species).
Figure 3 is a graph showing the ash content according to the loading height of coal coal species (A coal species, B coal species, C coal species).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The raw coal blending method for coke production of the present invention is blended for each stacking height at the time of blending the raw coal composed of a plurality of coal coal species, and manages the blending index of coal coal species so that the volatile content, ash content satisfies the setting range.

In order to manufacture coke for blast furnace, a large number of coals are generally blended, and in order to produce this coal into a coke suitable for blast furnace operation, volatile matter content of 24 to 26% by ash level and ash content exceeding 0 to 11.5% The blending index is controlled to be below.

Factors affecting the coke quality are largely divided into the characteristics of coal coal and operating conditions. Typical properties of the coal blend include fluidity, expansion rate, reflectance, and the like, and the operating conditions include crushing degree, moisture, loading density, dry temperature, and time.

The properties of blended coal can be adjusted within the standard range according to the supply and demand situation of the raw materials. The water content of the operating conditions varies according to the facilities of each plant, and the dry distillation temperature and time vary depending on the structure of the coke oven.

In particular, in the case of importing coal from abroad, coke is usually manufactured by mixing 10-18 coal species. Coal has different properties and characteristics according to the type of coal. Particle segregation occurs according to the pile height, and physical property changes according to the particle size.

Therefore, when blending a plurality of coal species, the blending index is managed based on the volatile and ash content of each coal to produce coke with excellent quality conditions.

Coal represents water, ash, volatiles, fixed carbon, etc. as a percentage.

Among these, volatile matter means volatile as a component which becomes dry gas among the components of coal. The measurement of volatile matter is regarded as volatile matter, after which dry coal is cut off from air, heated at 900 6 0 C for 7 minutes, and the moisture is subtracted from the loss. Volatilization is directly related to the coke quality. If the volatile content of the coal blend is less than 24% or more than 26%, the coke strength is lowered and the coke quality is reduced.

Ash means the ash (burning) remaining after burning coal. Ash affects the blast furnace post-process. If the ash content of the coal blend exceeds 11.5%, the ash content increases and the yield decreases because it does not provide breathability to the blast furnace.

The blending index includes the steps of investigating the particle size of each raw coal according to the pile height, examining the change of physical properties according to the particle size, and deriving the weighted average of the volatile content and ash content of each raw coal based on the changed physical properties. Is calculated through.

The weighted average is the blending ratio of each type of carbon such that the volatile content and the ash content satisfy 24 to 26% and 11.5% or less, respectively.

Each raw coal has a change in particle size according to the accumulation level, and this change in particle size is due to the content ratio of volatile ash and ash contained in coal.

As shown in FIG. 1, the particle size of the A type of coal is small at the pile height 20m, and the particle size is larger in the order of the C type and the B type. In addition, as shown in Figures 2 and 3, the higher the stacking height of coal coal species, the higher the volatile content and the ash tends to decrease. This tendency is due to the characteristics of coal, where the ash content increases with larger particle size and volatile content decreases.

In consideration of these characteristics, the quality of coke is improved and maintained by mixing coal by controlling the contents of volatile matter and ash by the pile height.

Hereinafter, the embodiment of the present invention will be described by experiment. However, the following examples are merely to illustrate the invention, the present invention is not limited by the following examples.

<Examples>

Particle size change was measured for A, B, and C types of coal coal species according to the pile height. Next, the volatile content and ash content of the A, B, C three kinds of coal coal species according to the pile height of the coal was measured.

Volatile content and ash content according to the pile height of coal coal species of A, B and C are shown in Table 1 below.

division
Volatility Ash 20m 10m 0m 20m 10m 0m A bullet type 33.7% 32.0% 30.2% 5.7% 6.9% 8.1% B type 24.8% 22.6% 20.4% 6.3% 9.8% 13.2% C type 22.7% 21% 19.3% 8.2% 11.2% 14.2%

The measurement results of Table 1 are the same as the data shown in the graphs of FIGS. 2 and 3.

As a result of the measurement in Table 1, the higher the pile height, the volatile content increased and the ash content decreased. In addition, the ash tends to decrease with increasing volatilization, showing a similar tendency.

Based on the measurement results in Table 1, the compounding ratios of A, B and C types of 20m pile heights, that is, weighted average values, are approximately 20%, 40% and 40%. This is calculated to satisfy the range of 24 ~ 26% of volatile matter content of coals containing A, B, and C types, and reduce the content of A, which has high volatile content at 20m height, and B, which has low volatile content, It is possible to adjust by increasing the content of C coal species.

In this case, the ash content tends to decrease in proportion to the volatile content that increases with the pile height. Therefore, if the weighted average value of the A, B and C types is calculated in consideration of the volatile content, the ash content also satisfies the set range. .

Table 2 calculates the weighted average of the A, B, and C types by stacking height in consideration of the volatile content and ash content of Table 1.

division A bullet type B type C type Volatility Ash Hot strength
(Aim: 67.6 ↑) Mixed coal 1
(20m) 20% 40% 40% 25.7% 7.0% 67.8 Mixed coal 2
(10m) 40% 30% 30% 25.9% 9.0% 67.6 Mixed coal 3
(0m) 50% 25% 25% 25.0% 10.9% 67.7

 According to Table 2, when calculating the weighted average value of A, B and C types in consideration of the volatile content and ash content for each pile height, the volatile content of the coal blend satisfies the range of 24 to 26%, and the ash content is 11.5. % Or less was satisfied.

In the case of blended coal 1, which is composed of a weighted average of 20% A, 40% B, and 40% C, the volatile content and ash content are calculated.

Volatile Content: (33.7 × 0.2 + 24.8 × 0.4 + 22.7 × 0.4) × 100 = 25.7%

Ash content: (5.7 × 0.2 + 6.3 × 0.4 + 8.2 × 0.4) × 100 = 7.0%, satisfying the setting range of volatile content and ash content.

In addition, when the above conditions are satisfied, the manufactured coke may also satisfy the hot strength standard of 67.6 or more.

Table 3 compares with Table 2, and combines A coal type, B coal type, and C coal type without considering pile height.

division A bullet type B type C type Volatility Ash Hot strength
(Aim: 67.6 ↑) Mixed coal 4
20% 40% 40% 23.8% 9.8% 67.5 Mixed coal 5
40% 30% 30% 25.9% 9.1% 67.6 Mixed coal 6
50% 25% 25% 26.9% 8.7% 67.4

Table 3 shows the compounding ratio by using the average data for each height of the A type, B type, and C type.

According to Table 3, when the A, B, and C types are combined without considering the stowage height, the volatile content does not satisfy the setting range as in the case of the coal 4 and coal 6, and the It is confirmed that cases where the hot strength criteria are not met may occur.

Through this, it can be seen that combining coal coal species in consideration of the pile height, volatile content, and ash content of each coal coal species is a method of improving coke quality.

This has the advantage of reducing the variables affecting the coke quality to improve the coke quality, further reduce the manufacturing cost and also improve the coke productivity.

The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the present invention, which is understood to be included in the configuration of the present invention.

Claims (4)

A method of mixing raw coal for coke production, characterized in that the mixing of the raw coal made of a plurality of coal coal species by compounding height, but the mixture index of the coal coal species such that the volatile content, ash content satisfies the set range. The method according to claim 1,
The compounding index is
Investigating the particle size of each raw coal according to the pile height;
Examining a change in physical properties according to the particle size;
Raw material coal blending method for producing coke, characterized in that derived through the step of calculating the weighted average value of the volatile content and ash content of each raw coal based on the investigated physical property changes. The method according to claim 2,
The weighted average
Raw material coal blending method for producing coke, characterized in that the volatile content and ash content is a compounding ratio for each pile type height so as to satisfy the set range. The method according to claim 1,
The setting range of the volatile matter content is 24 to 26%, and the setting range of the ash content is more than 0 and 11.5% or less.

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