JPS5847438B2 - Hard lump coke manufacturing method using low-rank coal and steam coal - Google Patents

Description

[Detailed Description of the Invention] Conventionally, as a method of reducing the cost of coke for blast furnaces, lump coke for mining furnaces has been manufactured from coking coal mixed with about 30% briquette coal, as has been done by blast furnace companies. However, the present invention takes a step forward by applying the manufacturing method of anhydrous briquettes, and as a result of repeated research for the purpose of manufacturing unique hard lump coke, the present invention has been developed to meet the currently used standards for blast furnace lump coke. We succeeded in obtaining something of higher quality.

According to the present invention, instead of using strong caking coal as the material used in the past, the material is made from a combination of pulverized granular thermal coal and anthracite coal, as well as coke powder from a coke factory, and the properties of each are taken into consideration. Mix in proportions and charge into the kiln.

In addition, when briquettes formed from the same coking coal without heat treatment and powdered coal are mixed and made into high-temperature dry distilled coke, large cracks and expansion occur in the coke mass due to the inherent moisture content or high volatile content, resulting in bubbles in the center. In order to prevent these drawbacks, it is possible to dehydrate the coal and devolatilize the volatile content by half by adjusting the temperature inside the kiln.

In other words, coal that has had its moisture and volatile content reduced through a heat treatment method in which the bituminous substances contained in the coal are brought into direct contact with hot air in a temperature range of 150°C to 300°C, which oozes out the bituminous substances contained in the coal without burning it. Modified to.

At this time, the coal changes from brown to black.

Before this black modified coal is discharged from the furnace and cooled, pitch powder or tar, or a solution of general asphalt or modified asphalt is added as a caking and adhesive agent, and mixed and stirred.

Since these additives all have malleability, they penetrate and permeate into the grain surfaces and pores of the modified coal, making the spaces between the grains oily.

Steam coal, anthracite coal, coke powder, etc. have poor softening and melting properties and belong to non-caking coals and do not have a bonding force between particles. can be modified to form a close bond with coking coal.

30-40% of the coal that has undergone these treatments, the remaining 70-40%
60% coke coking coal for mining furnaces is mixed together, and the mixture is further dispersed through a coarse crusher to achieve uniformity.

When this mixed coal is put into a known coke oven in powder form and subjected to high temperature dry distillation, dense and solid lump coke is produced.

The features of the method of the present invention are as follows when compared with the conventional method of mixing briquette coal.

In the manufacturing process: 1) It eliminates the need for most of the huge investment of funds such as molding machines, other auxiliary equipment, their basic construction, and the construction costs of high-rise buildings such as product coal storage tanks, kneaders, and sheds.

2) Since live steam is used during production in conventional methods, or is not used in this method, pollution such as contamination of gaseous gas by steam and waste water does not occur.

3) Even if this treated coal is deposited in the open air, it will not absorb rainwater because it is oil-covered.

Regarding coked products> ■) In this method, the moisture in the coal is reduced by heat treatment,
The volatile content is reduced by half, and there is no increase in attached moisture or reduced water compared to conventional methods, so the coke yield is good.

For example, the calculation is as follows.

U) In the conventional method of mixing briquette coal using steam, the average adhesion moisture of briquette coal (minimum) 8.5% Increase in reduced water due to steam 4.5% 10.5q
6 Moisture reduction due to certain compression 2.5% After mixing 30 tons of the above briquette coal and 70 yen of coking coal, the moisture content when feeding into the coke oven is (10.5% x 0).

3)+(8.5×0.7)=9.10%.

In this method, since the average moisture content of low-grade coal, steam coal, and coke powder is 8.5 liters, the moisture evaporates through heat treatment and the 10% content becomes zero.

If 30% of this reformed coal and 70% of coking coal are mixed and passed through a crusher, the moisture content will further decrease by about 1%, so the moisture content at the time of feeding into the coke oven will be (8.5 x 0.7) - 1. 0% = 4.95%II.

2) In the case of the conventional method of mixing briquette coal, it is difficult to uniformly mix briquette coal and coking coal when charging into a coke oven, making it difficult to produce homogeneous coke, but with this method, homogeneous mixing is easy and the finished coke There is no variation in any part.

3) In the conventional method, a large amount of fallen pulverized coal is generated due to breakage, abrasion, etc. during the period after the briquette is formed and before it is mixed in the coke oven, resulting in loss, but this does not occur with this method.

In this way, since no molding is required, a large amount of mechanical equipment is not required, resulting in significant savings in capital and lower manufacturing costs.

4) Compared to conventional methods, this method uses thermal coal, non-caking coal,
Since coke powder can be used, it is possible to significantly reduce raw material costs.

Below, the results of an industrial analysis comparing coke mixed with 30% briquette coal produced by the conventional method and lump coke mixed with 30 tons of heat-treated coal produced by the present method will be described.

Briquette molded according to this blending ratio 30%/I sample charcoal 1
0% was mixed and coked.

Sample coal (AI, 3 is a mixture of coke powder and steam coal) is heat-treated, then a binder is added and blended to infiltrate into the pores and cracks of the coal particles. 70% is mixed as it is, further uniformly dispersed in a crusher, and then subjected to high temperature dry distillation in a coke oven to obtain hard lump coke.

As can be seen from the above experimental results, the coke obtained by the method of the present invention is superior to the coke produced by mixing coal briquettes, and the properties of the coal have been investigated and the temperature of the hot air in the kiln has been determined. By adjusting the heat treatment, modifying the coal, and increasing or decreasing the amount of caking agent used, it is possible to develop thermal coal, non-caking coal, and expanded caking coal as coking coal for mining furnaces. It is also clear that it can be used.

Claims (1)

[Claims] 1 Steam coal or low-rank coal is pulverized to 2 to 3 M or less, charged into a kiln, and hot air from 150°C to 300°C is brought into direct contact with it in order to remove moisture and volatile matter from the coal. Pitch, tar, general asphalt, or modified asphalt is added to the heat-treated pulverized coal in a specified amount as a caking and adhesive agent, and by mixing and stirring, the surface of the coal particles is 30 to 40% of this treated coal is mixed with 70 to 60% of the coke raw coal for blast furnaces, and then passed through a crusher to achieve uniformity, followed by diffusion mixing, and this mixed coal is pulverized. A method characterized by producing hard lump coke by putting the lump coke into a coke oven.