KR101140999B1 - Method for improving cold strength and hot strength of coke - Google Patents

Abstract

The present invention relates to a method for improving the cold strength and hot strength of coke, and the present invention adds a crosslinking agent that causes a crosslinking reaction to coal, and prepares the coke by charging the coal with the crosslinking agent into a coke oven facility and heating and drying. .
The present invention has the advantage that it is possible to improve the strength of the coke without relying on the quality of the coal through the addition of fumed silica can broaden the choice of coal for coke production.

Description

Method for improving cold strength and hot strength of coke

The present invention relates to a method for improving cold strength and hot strength of coke, and more particularly, to a method for improving cold strength and hot strength of coke through addition of fumed silica.

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.

Coke must meet some quality criteria for its role as a heat source and reducing agent, as well as for improving the ventilation in the furnace.

Coke quality evaluation criteria include cold (room temperature) and hot strength. Cold strength and hot strength are required to maintain adequate strength so that coke does not collapse during transportation or in the furnace.

It is an object of the present invention to provide a method of improving the cold strength and hot strength of coke through the addition of fumed silica in order to maintain the coke strength without relying on coal quality.

According to a feature of the present invention for achieving the above object, the present invention adds a crosslinking agent that causes a crosslinking reaction to coal, and prepares coke by charging the coal with the crosslinking agent into a coke oven equipment and heating and drying. .

The crosslinking agent is fumed silica (Si [OH] n).

The fumed silica is added in a range of 0.1 wt% or more and less than 5.0 wt% based on the total weight of the coal.

The fumed silica has a particle size of 5 ~ 30nm so that the silanol (Si-OH) group is present.

 The furnace temperature of the coke oven equipment is maintained at 1110 ~ 1120 ℃, the heating time of the coal in the furnace is maintained for 1 to 3 hours after the central temperature of the coal reaches 850 ~ 950 ℃.

The present invention improves the strength of coke by crosslinking reaction in coal through fumed silica addition. This improves the strength of the coke without relying on the quality of the coal, thus broadening the choice of coal for coke production. Therefore, there is a useful effect that can bring about improved productivity and coke quality while reducing manufacturing costs.

1 is a schematic diagram showing the crosslinking reaction in coal through fumed silica addition.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the method for improving the cold strength and the hot strength of the coke of the present invention, a crosslinking agent is added to the coal, the coal to which the crosslinking agent is added is charged into a coke oven facility, and heated and dried to produce coke.

The cold and hot strength of the coke depends on the coking properties among the various properties of coal. High coke can be produced by uniformly mixing the caking component and the inert component by uniformly mixing coal (low reactivity) and coal (high reactivity) which are not excellent in caking.

The strength of the coke is influenced by the manufacturing process conditions, but the quality of the coal determines the strength of the coke. For this reason, the quality of the coke determines the strength and cost of the coke.

Thus, coke strength is improved through the addition of crosslinkers without depending on coal quality. Improving the coke strength without relying on coal quality can lead to a wider range of coal choices and reduce the cost of coke production because the quality of the coal does not have to depend on it.

The crosslinking agent is fumed silica (Si [OH] n).

Fumed silica causes crosslinking reaction with organic components in coal to improve the strength of coke. The crosslinking reaction serves to increase the tensile strength since the chain-shaped structure, as shown in FIG. 1, is changed into a network structure (three-dimensional network structure) and grows into a large molecular form. As tensile strength increases, cold and hot strengths improve.

Fumed silica is added to have a particle size of 5 ~ 30nm. Fumed silica has a surface area of 50 to 500 m 2 at this particle size, and silanol (Si-OH) groups are present on this surface. The presence of silanol groups on the silica surface increases the hydrophilicity and surface energy, thereby promoting the crosslinking reaction. At this time, the crosslinking reaction proceeds by attaching coal to O while H of the silanol group is separated.

The particle size of the fumed silica is difficult to manufacture in the process of less than 5nm, crosslinking reaction is lowered if it exceeds 30nm.

Fumed silica is added in the range of 0.1 wt% or more and less than 5.0 wt% of the total weight of coal. Fumed silica is added in less than 0.1wt% or more than 5.0wt% of the total weight of coal, there is no effect of improving the hot and cold strength of the coke. This is because the crosslinking reaction is insufficient when added at less than 0.1wt%, and coke strength is lowered by aggregation between fumed silica particles when added at 5.0wt% or more.

The loading density of coal to which fumed silica is added in the manufacture of coke is 740 to 760 kg / m ³ . The higher the loading density, the higher the coke quality, i.e., strength, after drying. The loading density depends on the moisture of the coal to be charged. In order to reduce the moisture of coal, large-scale facility investment is required, which leads to a cost increase.

The moisture content of coal is 7.7-8.3 wt%. Low moisture content of coal increases the loading density. However, the low moisture content may generate dust during transport and pollute the air, and in particular, there is a problem that requires a large-scale investment in the lower limit to be less than 7.7wt%.

The furnace temperature of the coke oven plant is 1110-1120 ° C. The furnace temperature is related to the strength of the coke and if it is lower than the above range, it is difficult to secure the strength, and if it is higher than the above temperature, brittleness may occur.

Coal added with fumed silica is made of coke through heated dry distillation which is maintained in the furnace for 1 to 3 hours, more precisely 2 hours after the core temperature reaches 850 to 950 ° C. In this process, volatile matter inside the coal and flue gas such as CO and CO ₂ are discharged to produce coke. The main component of the coke produced is carbon, and contains a small amount of hydrogen, nitrogen, sulfur, and oxygen.

The heating temperature is also related to the strength of the coke. If the above range is not satisfied, it is difficult to secure the strength, and excessive heating may increase brittleness.

Examples of the present invention will be described in comparison with other comparative examples. However, the following examples are merely to illustrate the invention, the present invention is not limited by the following examples.

≪ Example 1 >

The fumed silica of Table 1 was added to low volatile coal and high volatile coal, it charged in the coke oven installation, and produced coke by heating and drying, and measured the coke strength.

At this time, the coke production conditions were as follows.

Fumed Silica Particle Size: 25nm

-Loading Density: 750kg / m ³

Moisture: 8.0 ± 0.3%

Furnace temperature: 1100 ℃

Soaking time: Maintained for 2 hours after reaching 900 ℃ of coal core temperature.

Here, the low volatile coal is 3 to 7% volatile matter, the high volatile coal corresponds to 34 to 36% volatile coal. An example of low volatile coal is anthracite and an example of high volatile coal is bituminous coal.

division
Tan Zhong
Fumed silica
(wt%) Coke strength Remarks Cold strength Hot strength One Low volatile coal 0 80.8 64.3 Comparative example 2 Low volatile coal 0.05 80.8 64.4 Comparative example 3 Low volatile coal 0.1 81.3 64.7 Inventive Example 4 Low volatile coal One 81.4 64.8 Inventive Example 5 Low volatile coal 3 82.5 65.6 Inventive Example 6 Low volatile coal 5 84.8 67.3 Inventive Example 7 Low volatile coal 7 80.4 64.2 Comparative example 8 High Volatility Coal 0 76.6 57.3 Comparative example 9 High Volatility Coal 0.05 76.3 57.3 Comparative example 10 High Volatility Coal 0.1 78.1 59.5 Inventive Example 11 High Volatility Coal One 78.2 59.6 Inventive Example 12 High Volatility Coal 3 79.4 59.8 Inventive Example 13 High Volatility Coal 5 80.6 62.2 Inventive Example 14 High Volatility Coal 7 76.2 57.1 Comparative example

According to Table 1, coke strength increased with increasing fumed silica content in the range of 0.1-5 wt%.

And, when the content of fumed silica exceeds 5wt%, the hot and cold strengths of the coke are rather low. This is due to the aggregation between the fumed silica particles.

In the above experiment, the content range of fumed silica is relative, and it can be confirmed that the effect of improving the cold strength and hot strength of the coke in the amount of addition 0.1 ~ 5wt% is excellent.

<Example 2>

The effect of particle size of fumed silica on coke strength was measured.

At this time, the coke production conditions were as follows.

-Loading Density: 750kg / m ³

Moisture: 8.0 ± 0.3%

Furnace temperature: 1100 ℃

Soaking time: Maintained for 2 hours after reaching 900 ℃ of coal core temperature.

Here, the low volatile coal is 3 to 7% volatile matter, the high volatile coal corresponds to 34 to 36% volatile coal. An example of low volatile coal is anthracite and an example of high volatile coal is bituminous coal.

division Tanjong Fumed silica Coke strength Remarks
(wt%) Particle size Cold strength Hot strength One Low volatile coal 5 5 84.9 67.8 Inventive Example 2 Low volatile coal 5 25 84.8 67.3 Inventive Example 3 Low volatile coal 5 30 85.3 67.9 Inventive Example 4 Low volatile coal 5 35 80.8 64.3 Comparative example 5 High Volatility Coal 5 5 80.9 63.9 Inventive Example 6 High Volatility Coal 5 25 80.6 62.2 Inventive Example 7 High Volatility Coal 5 30 80.5 63.2 Inventive Example 8 High Volatility Coal 5 35 76.6 57.3 Comparative example

According to Table 2, when the fumed silica had a particle size of 5 to 30 nm, coke strength was improved regardless of coal quality. However, in the range where the particle size of fumed silica exceeds 30 nm, there was no change of coke strength compared with Table 1.

This is because when the particle size of fumed silica exceeds 30 nm, no silanol (Si-OH) group is present and thus no crosslinking reaction occurs.

Through this, it can be seen that the strength of the coke can be improved by the crosslinking reaction through fumed silica addition regardless of the quality of the coal. This can widen the choice of coal for coke production and has a useful effect of reducing manufacturing costs.

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 (5)

A crosslinking agent causing a crosslinking reaction to coal is added,
Coke is prepared by charging the coal to which the crosslinking agent is added to a coke oven facility and heat-drying it,
The crosslinking agent is fumed silica (Si [OH] n) characterized in that the cold strength and hot strength improvement method of the coke. delete The method according to claim 1,
The fumed silica is a method of improving the cold strength and hot strength of the coke, characterized in that added to less than 5.0wt% than 0.1wt% relative to the total weight of the coal. The method according to claim 3,
The fumed silica has a particle size of 5 ~ 30nm so that the silanol (Si-OH) group is present, characterized in that the cold strength and hot strength of the coke. The method of claim 4,
The furnace temperature of the coke oven equipment is maintained at 1110 ~ 1120 ℃
The heating time of the coal in the furnace is a method of improving the cold strength and hot strength of the coke, characterized in that to maintain for 1 to 3 hours after the central temperature of the coal reaches 850 ~ 950 ℃.

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