JPS58191784A - Production of coke - Google Patents

Abstract

PURPOSE:To obtain a coke with suppressed dusting, by separating a pulverized coal into a fine particulate coal and a coarse particulate coal during or after drying the pulverized coal, mixing the fine particulate coal with a highly fluidible coal, compressing the resultant mixed coal, mixing the coarse particulate coal with the compressed briquettes, charging the resultant mixture into a coke oven, and carbonizing the mixture. CONSTITUTION:A pulverized coal is separated into a fine particulate coal part and a coarse particulate coal part during or after drying the pulverized coal, and the separated fine particulate coal part is then mixed with a highly fluidible coal and pressure molded to give briquettes, which are directly or disintegrated and mixed with the above-mentioned coarse particulate coal part. The resultant mixture is then charged into a coke oven and carbonized to give the aimed coke. Preferably, water in an amount of 5wt% or less is added to the briquettes or a mixed coal of the coarse particulate coal with the briquettes to adjust the moisture thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of densely packing charged coal into a coke oven and carbonizing it.

High-quality caking coal, which is essential for producing coke for blast furnaces, is in short supply worldwide, and the coke manufacturing industry is increasing. Technology development is underway.

One of the technological developments is a method of densely packing coal into the carbonization chamber.

There are many methods for densely filling an IT-coke oven, such as a stamping method, a preheated charcoal charging method, a molded foot mixing method, and a dry charcoal charging method.

Among these methods, the stamping method and the preheated coal charging method are excellent methods for charging t-ll1@ of charging coal. However, these methods require special equipment and are difficult to apply to existing coke ovens.

Methods that can be easily applied to existing coke ovens are the briquette blending method or the dry coal charging method. The briquette blending method is already being implemented in many coke plants. However, in recent years, the cost of producing coke has increased due to the high price of binders, so improvements are required. On the other hand, the dry coal charging method is a technology that has started to attract attention because it can utilize waste heat energy discharged from a coke oven, but the charging Mt
-During drying, the dust-producing pulverized coal, which had formed similar particle tubes using water as a binder, separates and generates dust, which is a nuisance to the working environment and coke oven operation.

Many methods have been proposed to suppress dust-generating pulverized coal in this dry coal charging method. For example, special public service in 1973
In -28241, wet coal is subjected to fluidized drying, heavy oil is added to the dust generated at this time, and the dust is granulated to 1 to 3 kg in order to prevent the generation of 1 kt. Furthermore, in JP-A-55-48284, an attempt was made to prevent dust generation by separating and collecting dust from dried powder legs using a classifier, adding heavy oil pipes, and compressing and granulating the powder.

As described above, the known technology is characterized by collecting powder mt generated from dry coal, adding heavy oil, and granulating it, opening up the possibility of practical application of the dry coal charging method. . However, the use of expensive heavy oil increases the cost of coke production, similar to the briquette blending method. Furthermore, addition of heavy oil cannot be expected to significantly improve the strength of the coke product.

On the other hand, a method has also been proposed in which dust is strongly pressurized. This method has the disadvantage that the caking properties of the charged coal are reduced and extensive reforming of the Kuko grain coal cannot be expected.

In contrast to these known techniques, the present invention uses dust-producing pulverized coal VC
By adding and mixing highly fluid coal to 1 without adding a caking agent such as quality oil, and by improving the molding pressure during agglomeration, the dust generation is extremely low and the strength is low. It is a technology that has completed the production method of coke, and has simultaneously achieved the same prevention of dust generation and the same coke strength using a new method, and is a technology that is 6wT different from known technology at the intersection.

In other words, the pulverized wet coal is separated into a fine particulate coal part and a coarse particulate coal part during or after drying, and highly fluid coal is mixed with the separated fine particulate coal without adding all of the heavy oil. This method involves compressing and agglomerating the coal, mixing it with coarse particle coal, charging it into a coke oven, and carbonizing it.

When separating fine coal from coarse coal, it is desirable that the moisture content of powdered coal is 3 liters or less, and the separation method may be by IIIVC, but it is also reasonable to classify by airflow. In this case, the airflow is an inert gas or It is economically advantageous to use waste heat from a coke oven or the like. Furthermore, when using hot air, 7
The temperature should preferably be below 00°C.

The suitable classification point for pulverized coal is 0.2- from the point of view of airflow classification, but in order to improve the coking properties of pulverized coal, it is recommended to set it to 0.5.
However, depending on the function of the classifier, it may not be possible to completely remove the fine charcoal, and some coarse charcoal may be mixed with the fine charcoal. In some cases, it may be advantageous to incorporate some coarse grained coal to increase the apparent density of the agglomerated coal.

Conventional methods may be used for pressure molding the fine granular coal, but the smooth roll method is particularly preferred.In this case, the molding pressure is 3.7
kg/m or more, which is related to the particle size structure of the fine coal, it is possible to produce lump coal that sufficiently suppresses dust generation, and the strength of the product coke is also excellent, making it possible to pressure mold the lump coal.
However, if the particle size of agglomerated coal is large, if it is crushed to a certain particle size or less and the fine particle coal generated during crushing is removed and mixed, the particle size is 9i. Stable coke can be produced without causing any problems.

The dry charging coal according to the present invention, which is obtained by agglomerating mixed coal of fine-grained coal and highly fluidized coal and mixing it with coarse-grained coal, generates little dust and can be fully used as charging coal for coke production. However, if the moisture content of the charged coal is extremely low or if the transported coal is transported over a long distance, some dust may be generated.

In this case, spraying a water jet of liquid to control the humidity within a range that does not exceed 50% is highly effective, and the coke oven operation can be maintained without impairing the advantages of the dry coal charging method.

Next, the constituent elements of the present invention will be explained.

(l) @Separating the fine coal part from the charcoal is because if you try to implement the dry charcoal charging method, the pseudo particles formed using water as a binder will disintegrate due to the decrease in moisture, resulting in the formation of single granules. This is because pulverized coal generates dust, so it is necessary to separate and collect this dust-generating pulverized coal and agglomerate it to prevent dust generation.

The reason why particulate charcoal is pressure-molded to form agglomerated ash is to prevent this, since particulate charcoal has a significant dust-generating property up to that point. At the same time, high fluidity coal is also used in order to increase the strength of the cabinet. The reason why highly fluid coal is mixed into the particulate coal part is that the caking property of the particulate coal part has decreased and it is necessary to compensate for this. By agglomerating this mixed coal, it is possible to improve the reduced coking property of the fine particle coal. Furthermore, as a highly fluid coal, the maximum fluidity measured by Giesler and Silastometer is 500 D.
DPM or more is preferable. Furthermore, depending on the case, if the agglomerated coal is crushed, if the agglomeration processing capacity of fine-grained coal is to be increased compared to the equipment, it is necessary to increase the shape of the agglomerated coal.

In this case, homogeneous coke with large segregation of agglomerated coal may not be obtained. The easiest way to do this is to break it down. If crushing is to be carried out in detail, it is necessary to adjust not only the fluidity but also the degree of coalification so that the coking ability of agglomerated coal approximates that of coarse-grained coal.

The charged coal of the present invention, which is a mixture of agglomerated coal and coarse particle coal when dried and separated with a moisture content of 3 liters or less, has a moisture content of less than 3 liters, so the packing density in the coke oven is Therefore, high quality coke can be produced.

(2) Case 6 Therefore, the reason why water is added to the mixed coal of coarse particle coal and agglomerated coal or only to the agglomerated coal is that the water content of these coals according to the present invention is preferably less than 3 s, and furthermore, the water content of the agglomerated coal is Because no binder is added to the coal, dust may be generated if the charged coal is transported over a long distance. In order to prevent this, dust generation can be prevented by adding water in an amount not exceeding 5 g, and moreover, coke oven operation can be maintained satisfactorily without impairing the advantages of the dry coal charging method. If it is not desirable to add water, this can be solved by installing the agglomeration device near the coke oven.

Hereinafter, the content of the present invention will be described based on examples.

The powdered coal having the properties shown in Table 1 was used.

Table 1 Properties of powdered coal Example 1 The powdered coal shown in Table 1 was dried to a moisture content of 2.1% and separated into a fine coal portion and a coarse coal portion using a continuous fluidized bed while applying lifting motion.

13 Kasumi was added to the separated particulate charcoal, and 5
20 pieces of coal having a fluidity of 01 DDPM were mixed, rolled into lump coal by smooth rolls, and mixed with the coarse particle coal portion to prepare dry charging coal.

In this case, the thickness of the lump coal is 3.5■, and the apparent density is 1.2
It was 0 g/QC.

Example 2 Water was added to the dry charging coal prepared in Example 1 so that the moisture content became 4.0- to prepare charging coal.

Comparative Example 1 The powdered coal shown in Table 1 was dried to a moisture content of 2.1% and used as dry charging coal without being classified.

Comparative Example 2 Charged coal was adjusted by keeping the water content of the powdered coal in Table 1 constant at 5.5 cm.

Comparative Example 3 Five tons of tar was added to the pulverized coal separated in Example 1, and the mixture was agglomerated with a smooth roll, and then mixed with coarse particle coal to obtain charging coal.

Next, a dust generation test was conducted on the charged coal prepared using each method.

Charging coal into a cylindrical tube with an inner diameter of 125 mm and a height of 2,000 mm! Immediately after the drop, air of 1 m/8 was flowed from the bottom of the cylindrical tube, and the dust was collected on V paper by constant velocity suction. Table 2 shows the results of evaluating the horse-bearing ability based on the amount of dust.

Table 2 From the results in Table 2, the charged coal prepared according to the present invention has a small amount of generated dust and a moisture content of 5, which is considered to be the limit of moisture reduction.
The amount of dust generated is the same as that of Comparative Example 2, which uses 100% carbon, and is excellent as charging coal for metallurgical coke production. On the other hand, in Comparative Example 1 in which the dry charcoal was not agglomerated, dust generation was significant.

Furthermore, these charged coals are 450mm high, 600mm long,
The mixture was charged into an electric furnace having a carbonization chamber with a width of 400 square meters, and after the temperature of the coal type was raised to 1050°C, it was maintained for 3 hours for carbonization. The quality of coke produced by carbonization is determined by the drum strength D1.
1& and shown in Table 3.

Table 3 The method according to the present invention has higher coke strength than Comparative Example 3, in which dry coal is classified and then agglomerated by mixing tar into the pulverized coal, and has excellent properties as coke for large blast furnaces.

In view of the above points, the present invention is an excellent coke production method using dry charging coal, and has an extremely large stake in the coke industry, which is suffering from a lack of caking coal and a deterioration in the quality of coking coal.

Claims (1)

[Scope of Claims] 1. During drying, the powdered coal is separated into a fine particle foot portion and a coarse particle coal portion, and the separated fine particle coal is pressurized and formed into agglomerated coal. and then mixed with the coarse particle charcoal, charged into a coke oven and carbonized,
A coke production method in which high fluidity coal t-m is combined with a particulate coal portion and agglomerated under pressure to form t% mold. 2 Moisture 51 in lump coal or a mixture of coarse particle coal and lump coal
2. The coke manufacturing method according to claim 1, wherein the coke production method is characterized in that the water t is first humidified in a range below klS.