JPH04106193A - Method for controlling size of coal for coke making - Google Patents

Abstract

PURPOSE:To control the size of crushed raw coal so as to maximize the strength of produced coke by controlling the size using two points of crushed grain size sections including each one pint selected optionally from specific fine grain size section and coarse grain size section. CONSTITUTION:In the control of the size of crushed coal for coke making, the coal is crushed and the size of the crushed coal is controlled as follows. The control is effected by at least two points of crushed grain size sections including a fine grain size section which holds coal with sizes below one point of size selected optionally from the range of 0.1-1mm and a coarse grain size section which holds coal with sizes below one point of size selected from the range of 2-4mm. By controlling the size in this way, the size distribution curve of the crushed coal can be controlled distinctly. When this control method is adopted, a distinct size distribution is generally obtained by crushing the coal in such a way as to attain 20-30wt.% for the rate of the fine grain size section of the crushed coal and 78-87wt.% for that of the coarse grain size section.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the particle size of coking coal for coke production. This article relates to a method of controlling the grinding particle size so that the strength of the grinding material is maximized.

[Conventional technology]

Coke production is usually carried out by using several brands of coal as coking coal, using blending and pulverizing techniques to create appropriate charging coal, which is then charged into a coke oven and dried at high temperatures. be exposed.

Various methods have been proposed and implemented for adjusting the charged coal, such as so-called pulverization after blending raw coal and pulverization before blending. In any of the adjustment methods, the range in which the particle size of raw coal is controlled and the particle size is adjusted is important from the viewpoint of the strength of the produced coke.

Conventionally, for grain size control of coking coal, one point grain size classification,
For example, a particle size classification of 3 mm or less is adopted, and management is performed based on the percentage.

The above-mentioned conventional control method is mainly performed to prevent cracking of produced coke due to coarse-grained coking coal.

[Problem to be solved by the invention]

However, the conventional control method based on one particle size classification has the disadvantage that it is difficult to quantitatively understand factors that directly affect coke strength, such as the variation in coking coal properties by particle size and the charging density to the coke oven. be.

The above-mentioned drawbacks become a particular problem when the charging coal is adjusted by applying a pretreatment technique such as so-called classification and pulverization.

In other words, in classification and pulverization, when controlling the pulverized particle size of coking coal, the occurrence status of fine particles is important as well as the coarse particle size classification of coking coal, which is related to cracking of produced coke, but conventional management methods However, it is difficult to manage such duality.

The object of the present invention is to provide a method for controlling the particle size of coking coal for coke production, which solves the above-mentioned drawbacks.

[Means for Solving the Problems] That is, the gist of the present invention is to provide a method for pulverizing coking coal for coke production and controlling the particle size of the coking coal after pulverization. , a fine particle size classification below the particle size of one point arbitrarily selected from the range of 0.1 to 1 mm, and 2
A method for controlling the particle size of coking coal for coke production, characterized in that control is performed by at least two pulverized particle size classifications including a coarse particle size classification of one particle size or less arbitrarily selected from the range of ~4 mm. .

The present invention will be explained in detail below.

The method for controlling particle size of raw coal of the present invention is carried out by employing at least two pulverized particle size classifications for raw coal (single coal or blended coal) after pulverization.

One particle size classification in the present invention is 0°1~l
This is a particle size category (fine particle size category) that is below the particle size of one point arbitrarily selected from the range of mm, and the other particle size category is 2.
This is a particle size classification (coarse particle size classification) of one particle size or less arbitrarily selected from the range of ~4 mm.

In the present invention, it is possible to carry out management including particle size classifications other than the above-mentioned particle size classifications, but normally, management based on the two pulverized particle size classifications described above is sufficient.

The above-mentioned fine particle size classification is an index indicating the generation of a fine powder portion during the pulverization of coking coal, and this makes it possible to estimate the bulk density of coal charged into a coke oven.

In other words, Figure 1 shows the proportion and loading of the fine grain size in the charged coal when particle size is controlled by adopting a grain size of 0.3 mm or less as the fine grain size and a grain size of 3 aun or less as the coarse grain size. This is a graph showing the relationship between the charging bulk density and the charging bulk density (dry-kg/12). holds, and it is clear that the charging bulk density can be sufficiently estimated by fine particle size classification.

As is clear from FIG. 1, as the proportion of fine particles increases, the bulk density of the charge decreases due to over-grinding.

On the other hand, the above-mentioned coarse particle size classification is an index indicating cracking of coke produced by coking coal, and thereby enables estimation of coke strength.

In other words, as the proportion of coarse particles increases, as in the conventional case, this causes cracks to occur during coke formation, resulting in a decrease in coke strength.

Therefore, when adjusting the particle size by pulverizing raw coal, it is important to prevent over-pulverization and suppress the generation of fine particles as much as possible, while at the same time reducing the amount of coarse particles.

The above-mentioned antinomic pulverization can be achieved by pulverization to make the particle size distribution curve of the pulverized coking coal as sharp as possible, as shown in FIG.

In other words, Figure 2 is a graph showing the particle size distribution curve when coking coal is pulverized using the same pulverizer and changing the pulverizing conditions. The axis shows the particle size (mm), but the particle size distribution curve of the pulverized coal shown by the solid or dotted line is sharper than that of the unpulverized blended coal shown by the - dotted line. Crushed charcoal ■ is sharper.

The method of the present invention makes it possible to sharply control the particle size distribution curve of pulverized coking coal by controlling the particle size by employing two pulverized particle size classifications within a specific range.

The sharp particle size distribution as described above can be achieved by using the management method of the present invention. This is achieved by pulverizing raw coal to a content of 78 to 87% by weight.

〔Example〕

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

Raw coal having the blended coal properties shown in Example Table 1 was pulverized and 0.3 m
Particle size was controlled at two points: a fine particle size category of 3 mm or less and a coarse particle size category of 3 mm or less, and the charged coal particle size was determined as shown in Table 2. Next, the mixture was charged into a coke oven and coke was produced according to a conventional method.

The results are shown in Table-2.

Note that Table 2 also shows the measurement results of volatile matter (VM) by particle size and uniformity of charged coal properties, and the uniformity of charged coal properties is a value determined by the following formula.

C(VM) = Comparative Example Table 2 shows the results when particle size was controlled in the same manner as in the above example, except that particle size was controlled at one point in the coarse particle size category of 3 mm or less.

Incidentally, the total amount of 0.3 mm particle size products and 0.3 to 3 mm particle size products shown in Table 2 was 82.7%.
The result of further classification is -0,3+nmm
2.0% of m particle size products, 50.7% of 0.3-3mm particle size products
Met.

Moreover, each VM value of the 0.3 mm particle size product and the 0.3 to 3 mm particle size product is the value for the above-mentioned reclassified product.

As is clear from the results of Examples and Comparative Examples, according to the present invention, which controls the particle size of coking coal at two points according to a specific particle size distribution, coke with greater strength can be produced compared to the conventional one-point control method. can do.

Table 2 [Effects of the Invention] According to the method of the present invention explained above, an index for optimizing the pulverization conditions of coking coal is established, and as a result, the particle size of coking coal can be adjusted by optimal pulverization. can be expected, and a significant effect can be expected from the merits of blending various brands of charcoal.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the proportion of fine grain size in the charged coal and the charging bulk density, where the vertical axis is the charging bulk density (dry
-kg/12), and the horizontal axis indicates the proportion (wt%) of the fine particle size category. FIG. 2 is a graph showing the particle size distribution surface line, where the vertical axis shows the cumulative fractionation (% by weight) and the horizontal axis shows the particle size (m, . . . ).

Claims (2)

[Claims] (1) When pulverizing coking coal for coke production and adjusting the particle size, when pulverizing coking coal and controlling the particle size of coking coal after pulverization, the particle size is arbitrarily selected from the range of 0.1 to 1 mm. Management is performed using at least two pulverized particle size classifications, including a fine particle size classification of one point or less and a coarse particle size of one point or less arbitrarily selected from the range of 2 to 4 mm. A method for controlling particle size of coking coal for coke production. (2) The raw material for coke production according to claim 1, characterized in that the proportion of the fine particle size category of the pulverized coking coal is 20 to 30% by weight, and the proportion of the coarse particle size category is 78 to 87 weight%. Charcoal particle size control method.