JP5737002B2 - Method for producing blended coal for coke oven charging - Google Patents

Description

  The present invention relates to a method for producing blended coal charged in a coke oven, and more particularly to a method for pulverizing blended coal.

  Various cokes such as blast furnace coke are pulverized and blended with many brands of coal (coking coal) and then charged into the coke oven. The charged coal mixture is coke by being carbonized in the furnace. Coke strength is known as a quality control item that is particularly important in the production of coke. The coke strength depends on the grain size of the pulverized coal even if the coal blending conditions are the same.

  Therefore, the inventors of the present invention, as a method for increasing the coke strength, strongly pulverize high inert coal having a maximum length of 1.5 mm or more of coarse inert structure content of a boundary value (5 to 7% by volume) or more. The manufacturing method of the blast furnace coke including the crushing process to perform is disclosed (patent document 1).

JP 2008-297385 A

    However, in addition to the pulverization method disclosed in Patent Document 1, a pulverization method that can reliably improve coke strength has been desired. Then, an object of this invention is to provide the manufacturing method of the coal blend for coke oven charging for improving coke intensity | strength.

  The present inventors categorized coal used as coking raw material coal into high-inert coal and low-inert low-coalized coal, and manufactured a coal blend containing pulverized coal obtained by pulverizing these respectively. In the blended coal manufacturing method, the relationship between the pulverized particle size and coke strength of each of the high inert content coal and the low inert low coal content coal was investigated, and each of the high inert content coal and the low inert low coal content coal was examined. It has been found that the coke strength becomes maximum when the pulverized particle size reaches a certain range.

The present inventors classify coal used as coking raw material coal into high inert coal and low inert coal, and further classify low inert coal into high coal and low coal. In the method for producing a blended coal for charging a coke oven that produces a blended coal containing pulverized coal obtained by pulverizing each of these, the relationship between the pulverized particle size of low-coalized coal and coke strength was investigated. It was found that the strength of coke is maximized when the pulverized particle size of coalified coal reaches a certain range.
In the present specification, using a boundary value having a coarse inert structure content of 5 to 7% by volume, coal of a brand higher than the content is defined as a high inert coal, and the coarse inert structure content is the boundary. Coal with a grade below the value is defined as low inert coal. The setting of this boundary value will be described later.
Further, among low-inert coal, a coal having a vitrinite average reflectance Ro (%) higher than 0.9% is defined as a high-coalized coal, and a vitrinite average reflectance Ro (%) is 0.9%. The following brands of coal are defined as low-rank coal. In addition, the content of the coarse inert structure is that of the inert structure having a maximum length of 1.5 mm or more, which is included in the raw coal whose particle size is adjusted so that the cumulative% of the particle diameter of 3 mm or less is 70 to 80% by mass. It is defined as the content (vol.%). The details of this definition are described in Japanese Patent Application Laid-Open No. 2008-297385, and thus detailed description thereof is omitted.

  When the low-carbonized coal is strongly pulverized, the size of cracks generated in the inside is reduced, and the coke strength is increased. FIG. 2 is an enlarged photograph of a portion derived from low-rank coal in coke, and a portion indicated by an arrow is a crack. However, if the pulverized particle size of the low-carbonized coal is reduced beyond a certain boundary value, the low-carbonized coal having a low resolidification temperature is dispersed, thereby inhibiting the expansion of the high-carbonized coal. As a result, it was found that the increase in coke strength was hindered. And the present inventors discovered that this boundary value was fluctuate | varied with the total expansion coefficient of the whole coal blend including the low expansion coal and the low expansion coal. In this specification, the total expansion coefficient of the entire blended coal is defined as a value calculated by weighted averaging the total expansion ratio of each coal used in the blended coal with a blend ratio.

Furthermore, the present inventors have found that the effect of improving the coke strength by strongly pulverizing high inert-containing coal and appropriately pulverizing low-carbonized coal is dramatically improved.
More specifically, the method for producing a blended coal for charging a coke oven according to the present invention is as follows: (1) Cumulative% of a plurality of brands used as coking coal is 70 to 80% by mass with a particle size of 3 mm or less. The content of the coarse inert structure having a maximum length of 1.5 mm or more contained in the raw coal whose particle size was adjusted to be 5% to 7% by volume is used, and this content is more than the boundary value. Are classified into low-inert low-coalizing coals with high high-inert content coal and low-inert low-coalization coal with a coarse inert structure content below the boundary value and a vitrinite average reflectance of 0.9% or less. A method for producing a blended coal for charging a coke oven for producing a blended coal, wherein the high inert-containing coal is strongly pulverized such that a cumulative percentage of a particle size of 3 mm or less is 90% by mass or more; The overall expansion rate of the blended coal is 40% When full, the low-inert low-coalized coal with a total expansion rate of 20% or more is pulverized so that the cumulative percentage with a particle size of 3 mm or less is 82 to 88% by mass, and the total expansion rate is less than 20%. The low-inert low-coalized coal is pulverized so that the cumulative percentage with a particle size of 3 mm or less is 72 to 78 mass%, and when the total expansion coefficient of the entire blended coal is 40% or more, the total expansion coefficient is 20 % Of the low inert low-coalized coal with a particle size of 3 mm or less is pulverized so that the cumulative percentage with a particle size of 3 mm or less is 90% by mass or more. And a second step of pulverizing so that the cumulative percentage with a particle size of 3 mm or less is 82 mass% or more.

  The method for producing a blended coal for charging a coke oven according to the present invention is as follows: (2) For a low inert coal having a coarse inert structure content equal to or less than the boundary value, the vitrinite average reflectance is 0.9%. A method for producing a blended coal for charging a coke oven, which is classified into higher low-inert and high-coalized coal, and pulverized and blended respectively, and further comprising the low-inert and high-coalized coal And a third step of pulverizing so that the cumulative percentage of the particle size of 3 mm or less is 82 mass% or more and 88 mass% or less.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the coke oven charging coal blend with the extremely high effect of the coke strength improvement by the strong pulverization of coal can be provided.

It is process drawing which showed the manufacturing process of coke. It is an enlarged view (magnified photo) of the part derived from low-rank coal in coke

A method for producing coke will be described with reference to FIG. FIG. 1 is a process diagram showing a coke production process. In each of the coal yards 1A to 1E, single or plural brands of coal are stored. Each coal of each coal yard 1A-1E is conveyed to each compounding layer 2A-2E. The coal of each compounding layer 2A-2E is grind | pulverized in each grinder 3A-3E, respectively.
Here, when the coal pulverized in each of the pulverizers 3A to 3E is high-inert coal, strong pulverization is performed so that "cumulative percentage of particle size of 3 mm or less is 90 mass% or more". On the other hand, when the coal pulverized in each of the pulverizers 3A to 3E is low-inert coal and low-carbon coal, the total expansion rate of the low-carbon coal and the total blended coal An appropriate pulverized particle size is determined from the relationship with the expansion coefficient (details will be described later), and pulverized based on the pulverized particle size. Furthermore, when the coal pulverized in each of the pulverizers 3A to 3E is a low-inert coal and a high-coalized coal, the cumulative percentage with a particle size of 3 mm or less is 82% by mass or more and 88% by mass or less. ”

  The pulverized coal is blended and conveyed to the drying classifier 4. The blended coal contains fine powder that tends to generate dust in a coke oven. For this reason, the drying classifier 4 classifies the blended coal into coarse particles and fine powder while drying. The coarse particles are charged into the coke oven 6 as they are. The fine powder is conveyed to the agglomeration machine 5 and kneaded together with the caking additive, so that it is agglomerated into flakes or briquettes and charged into the coke oven 6.

  Next, the pulverization particle size corresponding to the brand of coal will be described in detail with reference to examples. Blended coal (1) -1, blended coal (1) -2, blended coal (1) -3, blended coal (2) -1, blended coal (2) -2 with different coal brands and / or blending ratios , The relationship between the pulverized particle size and the coke strength for blended coal (2) -3, blended coal (3) -1, blended coal (3) -2, blended coal (4) -1 and blended coal (4) -2 Examined.

  Table 1 shows the blends of Coal A, Coal B, Coal C, Coal D, Coal E, and Coal F included in Coal Coal (1) -1, Coal Coal (1) -2, Coal Coal (1) -3, respectively. The ratio and the coal properties of these coals A to F are shown. I (%) indicates the coarse inert content, Ro (%) indicates the vitrinite average reflectance, and TD (%) indicates the total expansion coefficient. In addition, the content of the coarse inert structure in the coal is 6% by volume as a boundary value, coal having a coarse inert content I (%) higher than 6% by volume is defined as the high inert content coal, and the coarse inert content I (% ) Will be described in detail below when the coal of 6 vol% or less is classified as low-inert coal.

  Coal A has a coarse inert content I (%) of 7.3%, a vitrinite average reflectance Ro (%) of 1.42%, a total expansion coefficient TD (%) of 98%, and is coarse Since the inert content I (%) is higher than 6%, it is a high-inert coal (hereinafter, sometimes referred to as a high-inert coal A). B charcoal has a coarse inert content I (%) of 8.7%, a vitrinite average reflectance Ro (%) of 1.40%, a total expansion coefficient TD (%) of 19%, and is coarse Since the inert content I (%) is higher than 6%, it is a high-inert coal (hereinafter, sometimes referred to as a high-inert coal B). Coal C has a coarse inert content I (%) of 7.6%, a vitrinite average reflectance Ro (%) of 1.22%, a total expansion coefficient TD (%) of 89%, and coarse Since the inert content I (%) is higher than 6%, it is a high-inert coal (hereinafter sometimes referred to as a high-inert coal C).

  D charcoal has a coarse inert content I (%) of 4.1%, a vitrinite average reflectance Ro (%) of 1.28%, a total expansion coefficient TD (%) of 150%, and is coarse Since the inert content I (%) is 6.0% or less and the vitrinite average reflectance Ro (%) is higher than 0.9%, it is a low inert high-coalizing coal (hereinafter referred to as high-coalizing coal). May be referred to as D).

  E charcoal has a coarse inert content I (%) of 3.5%, a vitrinite average reflectance Ro (%) of 0.72%, a total expansion coefficient TD (%) of 43%, and vitrinite Since the average reflectance Ro (%) is 0.9% or less, it is a low-inert low-coalized coal (hereinafter sometimes referred to as low-carbonized coal E). F charcoal has a coarse inert content I (%) of 4.3%, a vitrinite average reflectance Ro (%) of 0.69%, a total expansion coefficient TD (%) of 30%, and is coarse Since the inert content I (%) is 6.0% or less and the vitrinite average reflectance Ro (%) is 0.9% or less, it is a low inert low-coalizing coal (hereinafter referred to as low-coalizing coal). May be referred to as F).

  Blended coal (1) -1 contains 20% by mass of high inert-containing coal A, 20% by mass of high inert-containing coal B, 20% by mass of high coal content coal D, and low coal content coal E 25% by mass, and 15% by mass of low-carbonized coal F. The blended charcoal (1) -1 had a vitrinite average reflectance Ro (%) of 1.10%. Vitrinite average reflectance Ro (%) of blended coal (1) -1 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of coals A to F by blending ratio. The total expansion coefficient TD (%) of the blended coal (1) -1 was 69%. The total expansion coefficient TD (%) of the blended coal (1) -1 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to F with the blend ratio.

  The blended coal (1) -2 contains 10% by mass of the high inert content coal A, 25% by mass of the high inert content coal B, 15% by mass of the high inert content coal C, and 25% of the low-coalizing coal E Contains 25% by mass of low-carbonized coal F. The blended charcoal (1) -2 had a vitrinite average reflectance Ro (%) of 1.03%. The vitrinite average reflectance Ro (%) of the blended coal (1) -2 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals A to F by the blending ratio. The total expansion coefficient TD (%) of the blended coal (1) -2 was 46%. The total expansion coefficient TD (%) of the blended coal (1) -2 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to F with the blend ratio.

  The blended coal (1) -3 contains 10% by mass of the high inert content coal A, 20% by mass of the high inert content coal B, 30% by mass of the high coal content coal D, and low coal content coal E. 25% by mass, and 15% by mass of low-carbonized coal F. The blended charcoal (1) -3 had a vitrinite average reflectance Ro (%) of 1.09%. The vitrinite average reflectance Ro (%) of the blended coal (1) -3 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals A to F by the blending ratio. The total expansion coefficient TD (%) of the blended coal (1) -3 was 74%. The total expansion coefficient TD (%) of the blended coal (1) -3 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to F with the blend ratio.

  Table 2 shows the blending ratio of coals A to H contained in blended coal (2) -1, blended coal (2) -2, blended coal (2) -3, and the coal properties of these coals A to H. ing.

  G charcoal has a coarse inert content I (%) of 4.8%, a vitrinite average reflectance Ro (%) of 0.66%, a total expansion coefficient TD (%) of 15%, and is coarse Since the inert content I (%) is 6.0% or less and the vitrinite average reflectance Ro (%) is 0.9% or less, it is a low inert low-coalizing coal (hereinafter referred to as low-coalizing coal). May be referred to as G). H charcoal has a coarse inert content I (%) of 4.6%, a vitrinite average reflectance Ro (%) of 0.66%, a total expansion coefficient TD (%) of 3%, and coarse. Since the inert content I (%) is 6.0% or less and the vitrinite average reflectance Ro (%) is 0.9% or less, it is a low inert low-coalizing coal (hereinafter referred to as low-coalizing coal). May be referred to as H).

  The blended coal (2) -1 contains 10% by mass of the high inert content coal A, 35% by mass of the high inert content coal B, 20% by mass of the high coal degree coal D, and low coal degree coal G. 25% by mass and 10% by mass of low-carbonized coal H. The blended charcoal (2) -1 had an average vitrinite reflectance Ro (%) of 1.12%. The vitrinite average reflectance Ro (%) of the blended coal (2) -1 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals A to H with the blending ratio. The total expansion coefficient TD (%) of the blended coal (2) -1 was 51%. The total expansion coefficient TD (%) of the blended coal (2) -1 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to H with the blending ratio.

  The blended coal (2) -2 contains 30% by mass of the high inert content coal A, 40% by mass of the high inert content coal C, 5% by mass of the low coal content coal G, and the low coal content coal H. Contains 25% by mass. The blended charcoal (2) -2 had a vitrinite average reflectance Ro (%) of 1.11%. The vitrinite average reflectance Ro (%) of the blended coal (2) -2 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals A to H by the blending ratio. The total expansion coefficient TD (%) of the blended coal (2) -2 was 67%. The total expansion coefficient TD (%) of the blended coal (2) -2 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to H with the blend ratio.

  Table 3 shows the blending ratio of coals A to H contained in blended coal (3) -1 and blended coal (3) -2, and the coal properties of these coals A to H.

  The blended coal (3) -1 contains 10% by mass of the high inert content coal A, 30% by mass of the high inert content coal B, 10% by mass of the high coal degree coal D, and the low coal degree coal G. 25% by mass and 25% by mass of low-carbonized coal H. The blended charcoal (3) -1 had a vitrinite average reflectance Ro (%) of 1.02%. The vitrinite average reflectance Ro (%) of the blended coal (3) -1 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals A to H with the blending ratio. The total expansion coefficient TD (%) of the blended coal (3) -1 was 35%. The total expansion coefficient TD (%) of the blended coal (3) -1 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals A to H by the blend ratio.

  Blended coal (3) -2 contains 35% by mass of high inert coal B, 15% by mass of high inert coal C, 25% by mass of low coal G, and low coal H Contains 25% by mass. The blended charcoal (3) -2 had a vitrinite average reflectance Ro (%) of 1.00%. The vitrinite average reflectance Ro (%) of the blended coal (3) -2 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals B to H by the blending ratio. The total expansion coefficient TD (%) of the blended coal (3) -2 was 25%. The total expansion coefficient TD (%) of the blended coal (3) -2 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals B to H under blending conditions.

  Table 4 shows the blending ratio of coals BG contained in the blended coal (4) -1 and blended coal (4) -2, and the coal properties of these coals BG.

  Blended coal (4) -1 contains 45% by mass of high inert-containing coal B, 5% by mass of high coal content coal D, 25% by mass of low coal content coal E, and low coal content coal G 25 mass%. The blended charcoal (4) -1 had a vitrinite average reflectance Ro (%) of 1.04%. Vitrinite average reflectance Ro (%) of blended coal (4) -1 was calculated by weighted average of vitrinite average reflectance Ro (%) of coals B to G by blending ratio. The total expansion coefficient TD (%) of the blended coal (4) -1 was 30%. The total expansion coefficient TD (%) of the blended coal (4) -1 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals B to G with the blend ratio.

  Blended coal (4) -2 contains 30% by mass of high inert-containing coal B, 20% by mass of high inert-containing coal C, 25% by mass of low-carbonized coal F, Contains 25% by mass. The blended charcoal (4) -2 had a vitrinite average reflectance Ro (%) of 1.00%. The vitrinite average reflectance Ro (%) of the blended coal (4) -2 was calculated by weighted averaging the vitrinite average reflectance Ro (%) of the coals BG with the blending ratio. The total expansion coefficient TD (%) of the blended coal (4) -2 was 35%. The total expansion coefficient TD (%) of the blended coal (4) -2 was calculated by weighted averaging the total expansion coefficients TD (%) of the coals B to G with the blend ratio.

Table 5 shows the pulverized particle size of the low-coalized coal E in the blended coal (1) -1, 75% by mass, 82% by mass, 90% by mass, 95% by mass, and 100% by mass. The coke strength DI ¹⁵⁰ ₁₅ (-) of each blended coal (1) -1 when changed between% is shown. In the test of Table 5, the pulverized particle size of the high-inert coals A and B is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the high coal degree coal D is “the particle size is 3 mm or less. The crushed particle size of the low-coalized coal F was unified to "cumulative% with a particle size of 3 mm or less is 75 mass%".

Table 6 shows the pulverized particle size of the low-coalizing coal F in the blended coal (1) -2, and the cumulative percentage with a particle size of 3 mm or less is 75% by mass, 82% by mass, 90% by mass, 95% by mass, 100% by mass. The coke strength DI ¹⁵⁰ ₁₅ (-) of each blended coal (1) -2 when changed between% is shown. In the tests of Table 6, the pulverized particle size of the high inert coals A to C is “95% by mass of the cumulative particle size of 3 mm or less is 95% by mass”, and the pulverized particle size of the low coal degree coal E is “the particle size of 3 mm or less. The cumulative percentage was unified to 75% by mass.

Table 7 shows the blended coal (1) -3, in which the pulverized particle size of the low-coalizing coal E is 75% by mass, 82% by mass, 90% by mass, 95% by mass, and 100% by mass. The coke strength DI ¹⁵⁰ ₁₅ (-) of each blended coal (1) -3 when changed between% is shown. In the test of Table 7, the pulverized particle size of the high inert coals A and B is “95% by mass of the cumulative particle size of 3 mm or less is 95% by mass”, and the pulverized particle size of the high coal degree coal D is “the particle size of 3 mm or less. The crushed particle size of the low-coalized coal F was unified to "cumulative% with a particle size of 3 mm or less is 75 mass%".

Table 8 is a graph of the results of Tables 5 to 7, in which the horizontal axis indicates the pulverized particle size of the low-coalized coal, and the vertical axis indicates the coke strength DI ¹⁵⁰ ₁₅ (−) of the blended coal. Is shown.

From these Tables 5 to 8, in the case of blended coals (1) -1, (1) -2, (1) -3, the cumulative percentage with a particle size of 3 mm or less is 75 to 90% by mass. It was found that the coke strength DI ¹⁵⁰ ₁₅ (−) increased as the pulverized particle size increased. Further, it was found that the coke strength DI ¹⁵⁰ ₁₅ (−) is only slightly improved when the cumulative percentage with a particle size of 3 mm or less is larger than 90 mass%. Therefore, in the case of blended coals (1) -1, (1) -2, and (1) -3, the pulverized particle size of the low-coalizing coal is set to "cumulative percentage of particle size of 3 mm or less is 90 mass% or more" It was found that the coke strength can be improved by setting.

Table 9 shows that the blended coal (2) -1 has a pulverized particle size of the low-coalized coal G, and the cumulative percentage with a particle size of 3 mm or less is 72% by mass, 82% by mass, 88% by mass, 95% by mass, 100% by mass. The coke strength DI ¹⁵⁰ ₁₅ (-) of each blended coal (2) -1 when it is changed between%. In the tests shown in Table 9, the pulverized particle size of the high-inert coal A is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the high-inert coal B is “the cumulative% when the particle size is 3 mm or less. 95% by mass, the pulverized particle size of the high-coalized coal D is “85% by mass with a cumulative particle size of 3 mm or less”, and the pulverized particle size of the low-coalized coal H is “the cumulative% with a particle size of 3 mm or less”. To 75% by mass.

Table 10 shows the pulverized particle size of the low-coalized coal H in the blended coal (2) -2, in which the cumulative percentage with a particle size of 3 mm or less is 72 mass%, 82 mass%, 88 mass%, 95 mass%, 100 mass%. The coke strength DI ¹⁵⁰ ₁₅ (−) of each blended coal (2) -2 when changed between% is shown. In the test of Table 10, the pulverized particle size of the high-inert coals A to C is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the low-coalized coal G is “the particle size is 3 mm or less. The cumulative percentage was unified to 75% by mass.

Table 11 shows that in the blended coal (2) -3, the pulverized particle size of the low-coalized coal H is 72% by mass, 82% by mass, 88% by mass, 95% by mass, and 100% by mass with a particle size of 3 mm or less. The coke strength DI ¹⁵⁰ ₁₅ (−) of each blended coal (2) -3 when changed between% is shown. In the test of Table 11, the pulverized particle size of the high inert coal B is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the high coal degree coal D is “cumulative% when the particle size is 3 mm or less. Is 88 mass% ", and the pulverized particle size of the low-coalized coal G is unified to" cumulative percentage of particle size of 3 mm or less is 75 mass% ".

Table 12 is a graph of the results of Tables 9 to 11, with the horizontal axis indicating the pulverized particle size of the low-coalized coal and the vertical axis indicating the coke strength DI ¹⁵⁰ ₁₅ (-) of the blended coal. ing.

From these Tables 9-12, in the case of blended coals (2) -1, (2) -2, (2) -3, the cumulative percentage with a particle size of 3 mm or less is pulverized at a pulverized particle size of 72-82 mass%. It was found that the coke strength DI ¹⁵⁰ ₁₅ (−) increases as the particle size becomes finer. It was also found that the coke strength DI ¹⁵⁰ ₁₅ (−) hardly changed when the cumulative percentage with a particle size of 3 mm or less was larger than 82 mass%. Therefore, in the case of blended coals (2) -1, (2) -2, and (2) -3, the pulverized particle size of the low-coalizing coal is set to “cumulative percentage of particle size of 3 mm or less is 82% by mass or more”. It was found that the coke strength can be improved by setting.

Table 13 shows that in the blended coal (3) -1, the pulverized particle size of the low-coalizing coal G is 65% by mass, 72% by mass, 78% by mass, 85% by mass, and 95% by mass. The coke strength DI ¹⁵⁰ ₁₅ (−) of each blended coal (3) -1 when changed between% is shown. In the test of Table 13, the pulverized particle size of the high inert coals A and B is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the high carbonized coal D is “the accumulated particle size is 3 mm or less. % Is 85% by mass ”, and the pulverized particle size of the low-carbonized coal H is unified as“ cumulative% having a particle size of 3 mm or less is 75% by mass ”.

Table 14 shows that, in the blended coal (3) -2, the pulverized particle size of the low-coalized coal H is 65% by mass, 72% by mass, 78% by mass, 85% by mass, and 95% by mass with a cumulative particle size of 3 mm or less. The coke strength DI ¹⁵⁰ ₁₅ (−) of each blended coal (3) -2 when changed between the two is shown. In the test of Table 14, the pulverized particle size of the high inert coals B and C is “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of the low-coalized coal G is “the particle size is 3 mm or less. The cumulative percentage was unified to 75% by mass.

Table 15 is a graph of the results of Tables 13 and 14, where the horizontal axis indicates the pulverized particle size of the low-coalized coal and the vertical axis indicates the coke strength DI ¹⁵⁰ ₁₅ (-) of the blended coal. .

From Table 13 to Table 15, in the case of blended coals (3) -1 and (3) -2, the pulverized particle size increases in the pulverized particle size in which the cumulative percentage of the particle size of 3 mm or less is 65 mass% to 72 mass%. As a result, the coke strength DI ¹⁵⁰ ₁₅ (−) increased, and the coke strength DI ¹⁵⁰ ₁₅ (−) was found to be substantially constant at a pulverized particle size of 72 mass% to 78 mass%. Further, it was found that when the cumulative percentage of the particle size of 3 mm or less is larger than 78% by mass, the coke strength DI ¹⁵⁰ ₁₅ (−) decreases as the pulverized particle size increases. Therefore, when blended coals (3) -1 and (3) -2 are used, the pulverized particle size of the low-coalizing coal is set to "cumulative percentage of particle size of 3 mm or less is 72 mass% to 78 mass%". It was found that the coke strength can be improved.

Table 16 shows that in the blended coal (4) -1, the pulverized particle size of the low-coalizing coal E is 72% by mass, 82% by mass, 88% by mass, 95% by mass, 100% by mass with a cumulative particle size of 3 mm or less. when changing between, the coke strength ^DI _{0.99 15} of each coal blend (4) -1 - shows (). In the test of Table 16, the pulverized particle size of the high inert coal B is “95% by mass when the particle size is 3 mm or less”, and the pulverized particle size of the high carbonized coal D is “the accumulated% when the particle size is 3 mm or less. The pulverized particle size of the low-coalized coal G was unified to “85% by mass” and “cumulative% having a particle size of 3 mm or less is 75% by mass”.

Table 17 shows that in the blended coal (4) -2, the pulverized particle size of the low-coalizing coal F is 72% by mass, 82% by mass, 88% by mass, 95% by mass, and 100% by mass with a cumulative particle size of 3 mm or less. The coke strength DI ¹⁵⁰ ₁₅ (−) of each blended coal (4) -2 when changed between the two is shown. In the test of Table 17, the pulverized particle size of the high inert coals B and C is “95% by mass when the particle size is 3 mm or less”, and the pulverized particle size of the low-coalized coal G is “3 mm or less particle size”. The cumulative percentage was unified to 75% by mass.

Table 18 is a graph of the results of Tables 16 and 17, with the horizontal axis indicating the pulverized particle size of the low-coalized coal and the vertical axis indicating the coke strength DI ¹⁵⁰ ₁₅ (-) of the blended coal. .

From these Tables 16 to 18, in the case of blended coals (4) -1 and (4) -2, the pulverized particle size increases in the pulverized particle size in which the cumulative percentage of the particle size of 3 mm or less is 72 mass% to 82 mass%. It was found that the coke strength DI ¹⁵⁰ ₁₅ (−) increased, and the coke strength DI ¹⁵⁰ ₁₅ (−) was substantially constant at a pulverized particle size of 82% by mass to 88% by mass. Further, it was found that when the cumulative percentage with a particle diameter of 3 mm or less is larger than 88 mass%, the coke strength DI ¹⁵⁰ ₁₅ (−) decreases as the pulverized grain size increases. Therefore, when blended coal (4) -1 and (4) -2 are used, the pulverized particle size of the low-coalizing coal is set to "cumulative percentage of particle size of 3 mm or less is 82 mass% to 88 mass%". It was found that the coke strength can be improved.

  Table 19 is a graph illustrating the relationship between the total expansion rate of each of the blended coals (1) -1 to (4) -2 and the simple total expansion rate of the low inert low-coalizing coal, and the horizontal axis represents the blending. The total expansion rate of the whole charcoal is shown, and the vertical axis shows the simple total expansion rate of the low inert low-coalizing coal that is subject to strong pulverization. In the case of blended coal (1) -1, the simple expansion rate of low coal degree coal E is plotted on the vertical axis, and in the case of blended coal (1) -2, the simple expansion rate of low coal degree coal F is plotted on the vertical axis. In the case of blended coal (2) -1, the simple expansion rate of the low-coalizing coal G is plotted on the vertical axis, and in the blended coal (2) -2, the simple expansion rate of the low-coalizing coal H is plotted on the vertical axis. In the case of blended coal (3) -1, the simple expansion rate of low-coalizing coal G is plotted on the vertical axis, and in the case of blended coal (3) -2, the simple expansion rate of low-coalizing coal H is plotted on the vertical axis. In the case of blended coal (4) -1, the simple expansion rate of the low-coalizing coal E is plotted on the vertical axis, and in the blended coal (4) -2, the simple expansion rate of the low-coalizing coal F is plotted on the vertical axis. Yes. Each of the blended coals (1) -1 to (4) -2 contains a plurality of low-grade coals, but in order to easily confirm the effect of pulverizing the low-inert low-coal coals, Only two low inert coals were noted.

  In Table 19, when the boundary value of the total expansion rate of the entire blended coal is 40% and the boundary value of the simple total expansion rate of the low inert low-coalized coal is 20%, the blending is performed in four regions. Charcoal (1) -1, (1) -2, (1) -3 has a total expansion rate of 40% or more of the entire blended coal, and the simple total expansion rate of the low inert low-coalizing coal Classified as Region 1 that is 20% or more, the blended coals (2) -1, (2) -2, and (2) -3 have a total expansion rate of 40% or more and a low inert It is classified into the region 2 in which the total expansion rate of low-rank coal is less than 20%, and the total expansion rates of the blended coals (3) -1 and (3) -2 are less than 40%. In addition, the simple total expansion rate of the low inert low-coalizing coal is less than 20%, and is classified into region 3, and the blended coals (4) -1 and (4) -2 are the total expansion of the entire blended coal. A rate of less than 40%, and are classified into region 4 low inert low coalification degree coal PLAIN total expansion of 20% or more.

  Therefore, when the boundary value of the total expansion coefficient of the entire blended coal is 40% or more, the pulverized particle size (region 1) of the low inert low-carbonized coal having a total expansion coefficient of 20% or more is expressed as “cumulative% of particle diameter of 3 mm or less. Is set to “90% by mass or more”, and the pulverized particle size of the low inert low-coalized coal (region 2) having a total expansion rate of less than 20% is set to “cumulative% of particle size of 3 mm or less is 82% by mass or more”. . When the boundary value of the total expansion rate of the entire blended coal is less than 40%, the pulverized particle size of the low inert low-carbonized coal (region 3) having a total expansion rate of less than 20% is expressed as “cumulative% with a particle size of 3 mm or less is 72%. “Mass% to 78% by mass” and the pulverized particle size of low inert low-coalizing coal (region 4) having a total expansion rate of 20% or more is changed to “cumulative% of 3 mm or less is 82% to 88% by mass”. It was proved that the coke strength can be increased by setting.

  As described above, according to the present embodiment, the blended coal and the low-carbon coal to be used are classified in the regions 1 to 4, and the coke is set by setting the pulverization particle size according to the classified region. Strength can be improved.

  However, the effect of improving the coke strength by pulverizing low-inert low-coalized coal as described above is high-inert-containing coal containing more coarse inert, that is, the content of coarse inert is higher than 6%. It is expressed by pulverizing high inert coal (hereinafter simply referred to as high inert coal). Examples will be described below in more detail. Table 20 corresponds to Table 5 and differs from Table 5 in that the high inert carbons A and B are pulverized with a pulverized particle size of “90% by mass of cumulative percentage of particle size of 3 mm or less”. Table 21 corresponds to Table 5 and differs from Table 5 in that the inert coals A and B are pulverized with a pulverized particle size of “cumulative percentage of particle size of 3 mm or less is 80 mass%”. Table 22 is a graph of the results of Table 5, Table 20, and Table 21.

When the pulverization particle size of the high inert content A and B is set to “80% by mass when the cumulative particle size is 3 mm or less”, the pulverization particle size of the low-coalized coal is “75% by mass when the particle size is 3 mm or less”. The coke strength DI ¹⁵⁰ ₁₅ (−) increased only by 0.3 even when “cumulative percentage with a particle size of 3 mm or less was increased to 100 mass%”. On the other hand, when the pulverized particle size of the high inert-containing coals A and B is set to “90% by mass, the cumulative percentage of the particle size of 3 mm or less is 90% by mass”, the pulverized particle size of the low-carbonized coal is “the cumulative particle size of 3 mm or less. % ”Increased from“ 75% by mass ”to“ 100% by mass with a particle size of 3 mm or less ”, the coke strength DI ¹⁵⁰ ₁₅ (−) increased by 1.3. In addition, when the pulverized particle size of the high-inert coals A and B is set to “95% by mass of the cumulative particle size of 3 mm or less is 95% by mass”, the pulverized particle size of the low-carbonized coal is “75% of the particle size of 3 mm or less is 75%. By increasing from “mass%” to “accumulated percentage of particle size of 3 mm or less is 100 mass%”, the coke strength DI ¹⁵⁰ ₁₅ (−) increased by 1.2. From these results, it was proved that the coke strength is remarkably increased by setting the pulverized particle size of the high-inert-containing charcoal to “the cumulative percentage of the particle size of 3 mm or less is 90% by mass or more”.

  Table 23 corresponds to Table 6 and differs from Table 6 in that the high inert content A to C is pulverized under the condition that “cumulative percentage of particle size of 3 mm or less is 90 mass%”. Table 24 corresponds to Table 6 and differs from Table 6 in that the high inert coals A to C are pulverized under the condition that “cumulative percentage of particle size of 3 mm or less is 80 mass%”. Table 25 is a graph of the results of Table 6, Table 23, and Table 24.

When the pulverized particle size of the high inert-containing coals A to C is set to “80% by mass when the cumulative particle size of 3 mm or less is 80% by mass”, the pulverized particle size of the low-coalized coal is “75% by mass when the particle size is 3 mm or less. The coke strength DI ¹⁵⁰ ₁₅ (−) increased only by 0.3, even when the cumulative percentage with a particle size of 3 mm or less was increased to “100 mass%”. On the other hand, when the pulverized particle size of the high inert content A to C is set to “90% by mass of cumulative particle size 3 mm or less is 90% by mass”, the pulverized particle size of low-carbonized coal is “cumulative% of particle size 3 mm or less. The coke strength DI ¹⁵⁰ ₁₅ (−) was increased by 1.5 by increasing “75% by mass” from “cumulative% of particle size of 3 mm or less to 100% by mass”. Further, when the pulverized particle size of the high inert content A to C is set to “95% by mass of the cumulative particle size of 3 mm or less is 95% by mass”, the pulverized particle size of the low-carbonized coal is 75% by mass of the particle size of 3 mm or less. By increasing the “%” to “the cumulative percentage of the particle size of 3 mm or less is 100 mass%”, the coke strength DI ¹⁵⁰ ₁₅ (−) is increased by 1.4. From these results, it was proved that the coke strength is remarkably increased by setting the pulverized particle size of the high-inert-containing charcoal to “the cumulative percentage of the particle size of 3 mm or less is 90% by mass or more”.

As described above, the pulverization particle size of the high-inert coal is set to “cumulative percentage of particle size of 3 mm or less is 90% by mass or more”, and low-inert low-coalizing coal is appropriately strongly pulverized according to the total expansion rate. By doing so, the reason why the coke strength effect is remarkably increased is considered as follows.
Inerts with the same size and low-grade coals generally have a greater effect on coke strength reduction. Therefore, under conditions where there are many large-sized inerts in the blended coal, cracks around the inert are a major defect that determines the coke strength. small. On the other hand, under conditions where there is almost no large-sized inert in the blended coal, cracks around the inert do not become a major defect, so the strength of coke is dramatically improved by pulverizing low-carbon coal. it is conceivable that.
In addition, when a low inert high-coalized coal having a coarse inert content of 5 to 7% by volume or less and a vitrinite average reflectance of 0.9% or more is further blended, a predetermined pulverized particle size range is obtained. It is more preferable to grind. Table 26 corresponds to Table 7 and is different from Table 7 in that the high-coalized coal D is pulverized under the condition that “cumulative percentage with a particle size of 3 mm or less is 95 mass%”. Table 27 corresponds to Table 7 and is different from Table 7 in that the high-coalized coal D is pulverized under the condition that “cumulative% with a particle size of 3 mm or less is 82% by mass”. Table 28 corresponds to Table 7, and differs from Table 7 in that the high-coalized coal D is pulverized under the condition that “cumulative percentage of particle size of 3 mm or less is 75 mass%”. Table 29 is a graph of the results of Table 6, Table 26, Table 27, and Table 28.

As shown in Table 29, when the pulverized particle size of the high-coalized coal D is “82% by mass when the particle size is 3 mm or less” and “88% by mass when the particle size is 3 mm or less is 88% by mass”, The coke strength DI ¹⁵⁰ ₁₅ is higher than when the cumulative percentage with a diameter of 3 mm or less is 75 mass% and the cumulative percentage with a particle diameter of 3 mm or less is 95 mass%. From these results, the coke strength DI ¹⁵⁰ ₁₅ (−) is maximized by setting the pulverized particle size of the high coal degree coal D to “cumulative% having a particle size of 3 mm or less is 82 mass% to 88 mass%”. Therefore, it turned out that it is preferable.

  Table 30 corresponds to Table 11 and is different from Table 11 in that the high-coalized coal D is pulverized under the condition that “cumulative percentage with a particle size of 3 mm or less is 95 mass%”. Table 31 corresponds to Table 11 and is different from Table 11 in that the high degree coalized coal D is pulverized under the condition that “cumulative% with a particle size of 3 mm or less is 82% by mass”. Table 32 corresponds to Table 11 and is different from Table 11 in that the high-coalized coal D is pulverized under the condition that “cumulative percentage with a particle size of 3 mm or less is 75 mass%”. Table 33 is a graph of the results of Table 11, Table 30, Table 31, and Table 32.

As shown in Table 33, when the pulverized particle size of the high-degree coalized coal D is “82% by mass when the particle size is 3 mm or less” and “88% by mass when the particle size is 3 mm or less”, The coke strength DI ¹⁵⁰ ₁₅ is higher than when the cumulative percentage with a diameter of 3 mm or less is 75 mass% and the cumulative percentage with a particle diameter of 3 mm or less is 95 mass%. From these results, since the coke strength DI ¹⁵⁰ ₁₅ (−) is maximized when the pulverized particle size of the high-coalized coal D is “82% by mass to 88% by mass with a particle size of 3 mm or less”, it is preferable. I understood that.
Thus, it is considered that the reason why the pulverized particle size of the high-coalized coal D becomes maximum when “the cumulative percentage of the particle size of 3 mm or less is 82% or more and 88% by mass or less” is as follows.
When the pulverized particle size of the low inert and high coalified coal is too coarse, there are many coarse particles having a high expansion coefficient in the blended coal. When coal with a low expansion coefficient is present around the coarse particles, the coarse particles of the high-coalized coal will expand freely, and at the same time, the bubbles generated in the coarse particles will burst, producing large connected pores connecting multiple bubbles. To do. These large connected pores cause a reduction in coke strength. Therefore, if the coarse particles with high expansion coefficient are pulverized and reduced, the probability of existence of highly expandable particles around the high expansion charcoal increases due to the increase in the number of high expansion charcoal particles. It is thought that the effect of suppressing the free expansion of the expansion coefficient carbon particles can suppress the formation of large connected pores and increase the coke strength.
On the other hand, if the pulverized particle size of the low inert high-coalized coal is too fine, the expansion rate of the coal itself is significantly reduced, so that the adhesiveness between the coal particles is deteriorated and the coke strength is reduced.
From these results, it is preferable to set the pulverized particle size of the high-coalized coal to “the cumulative percentage of the particle size of 3 mm or less is 82% or more and 88% by mass or less” because the coke strength is dramatically increased.

By the way, the pulverization particle size of the above-mentioned high inert coal is set to “cumulative percentage of particle size of 3 mm or less is 90% by mass or more”, and the pulverization particle size of low inert coal is appropriate according to the total expansion rate. The synergistic effect in which the coke strength effect is remarkably increased by setting to will be described in more detail.
Table 34 shows the coal properties of Coal I, Coal J, and Coal K. Coal I is a high-inert coal because the content of coarse inert is higher than 6% (hereinafter sometimes referred to as high-inert coal I). Coal J and K have a coarse inert content of less than 6%, and vitrinite average reflectance Ro (%) is lower than 0.9%. Therefore, low inert low coal content coal (hereinafter referred to as low coal content coal) J, K may be referred to). Coal J has a total expansion rate of 20% or more, and coal K has a total expansion rate of less than 20%. Using the coal blended with these high-inert coal I and low-carbonized coals J and K in the ratio (mass%) shown in Table 35, the relationship between the pulverized particle size and coke strength DI ¹⁵⁰ ₁₅ (-) Examined. The total expansion rate of the blended coal is 65%.

The pulverized particle size was changed between level 1 and level 4 as shown in Table 36.
In the case of Level 1 blended coal, all the pulverized particle sizes of high inert coal I and low coals J and K are set to “cumulative percentage of particle size of 3 mm or less is 80% by mass” and then coke to obtain coke strength DI. ¹⁵⁰ ₁₅ (−) was measured.
For level 2 blended coal, the pulverized particle size of high-inert coal I is set to "80% by mass with a cumulative particle size of 3 mm or less is 80% by mass", and the pulverized particle size of low-carbonized coal J with a total expansion rate of 20% or more. Is set to “95% by mass of the cumulative particle size of 3 mm or less” and the pulverized particle size of the low-carbonized coal K having a total expansion rate of less than 20% is set to “85% by mass of the cumulative particle size of 3 mm or less” After setting, coke was formed and coke strength DI ¹⁵⁰ ₁₅ (−) was measured. That is, at level 2, only the low-coalized coals J and K are strongly pulverized without strongly pulverizing the high-coalized coal I containing a large amount of inert.
In the case of level 3 blended coal, the pulverized particle size of high-inert coal I is set to “95% by mass when the particle size is 3 mm or less is 95% by mass”, and the pulverized particle size of low-coalized coal J is “cumulative particle size of 3 mm or less. % Is set to 75% by mass, and the pulverized particle size of the low-coalizing coal K is set to “cumulative% of particle size of 3 mm or less is 75% by mass”, and then coked to obtain coke strength DI ¹⁵⁰ ₁₅ (−). It was measured. That is, at level 3, the high-inert coal I containing a large amount of inert was pulverized and the low-coalizing coals J and K were not pulverized.
For level 4 blended coal, the pulverized particle size of high-inert coal I is set to “95% by mass with a cumulative particle size of 3 mm or less is 95% by mass”, and the pulverized particle size of low-coalized coal J with a total expansion rate of 20% or more. Is set to “95% by mass of the cumulative particle size of 3 mm or less” and the pulverized particle size of the low-carbonized coal K having a total expansion rate of less than 20% is set to “85% by mass of the cumulative particle size of 3 mm or less” After setting, coke was formed and coke strength DI ¹⁵⁰ ₁₅ (−) was measured.
In addition, in order to make the bulk density constant in any level, after drying the blended coal to 2% by mass and classifying it with 0.5 mm, pulverized coal of 0.5 mm or less is agglomerated into flakes and briquettes. After mixing with the above coarse coal, it was charged into a coke oven and coked.

The coke strength DI ¹⁵⁰ ₁₅ (−) of the coke manufactured based on the level 1 to the level 4 and the change amount ΔDI ¹⁵⁰ ₁₅ (−) of the coke strength DI ¹⁵⁰ ₁₅ (−) based on the level 1 are shown. 37.

These results are shown in the graph of Table 38. In the graph of Table 38, the horizontal axis represents the pulverized particle size of the entire blended coal, and the vertical axis represents the coke strength DI ¹⁵⁰ ₁₅ (−) of the entire blended coal.

Level 2 has a change amount ΔDI ¹⁵⁰ ₁₅ (−) of 0.3, and level 3 has a change amount ΔDI ¹⁵⁰ ₁₅ (−) of 1.0. When these are added, the change amount ΔDI ¹⁵⁰ ₁₅ (−) is 1. .3. However, at level 4, the change ΔDI ¹⁵⁰ ₁₅ (−) was 1.9. In other words, the high-inert coal is strongly pulverized under the condition that “cumulative percentage of particle size of 3 mm or less is 90% by mass or more” and synergistic effect of strongly pulverizing low-carbon coal according to the four-quadrant graph of Table 17. As a result, it was proved that the strength of coke was drastically improved.

As described above, coal having a coarse inert structure content of 6% by volume as a boundary value, coal having a coarse inert content I (%) higher than 6% is regarded as a high inert content coal, and coarse inert content I (%) Has described the case where 6% or less of coal is classified as low inert coal.
Here, in the present invention, using a boundary value having a coarse inert structure content of 5 to 7% by volume, a coal having a higher content is defined as a high inert coal, and containing a coarse inert structure A coal whose quantity is less than the boundary value is defined as a low inert coal. The concept of setting this boundary value is described below.

  When blending a plurality of brands of coal for coke production, the particle size of the blended coal is set within a range of particle sizes that allow the production of coke. Therefore, the pulverization particle size and blending ratio of each brand of coal are limited by the set value of the coal blend particle size.

  Therefore, if the blending ratio of brand coal with relatively high coarse inert content is large, and if all the brand coal with relatively high coarse inert content is pulverized, the grain size of the blended coal will become finer. In some cases, the granularity cannot be adjusted to the set granularity. In such a case, by setting the boundary value of the coarse inert content to a higher value within the range of 5 to 7% by volume, the blended coal can have a desired set particle size.

  On the other hand, if the blending ratio of brand coal with relatively high coarse inert content is small, conversely, the boundary value of coarse inert content is set to a lower value within the range of 5-7% by volume. By doing, blended charcoal can be made into a desired set particle size.

  Hereinafter, the case where the set particle size of the blended coal is 3 mm or less and 85% by mass will be described as an example using Table 39. Condition 1 is a case where W coal, X coal, and Z coal are blended as brands of coal. W coal is a high inert content coal because the coarse inert content is 7.3%, and Z coal is coarse inert. It is clear that it is a low inert coal because the content is 3.5%, but the X coal is in the boundary region of 5-7% because the coarse inert content is 6.6%, so the boundary It is necessary to set a value.

  In this condition 1, the blending ratio of W coal is 50%, the blending ratio of X coal is 30%, and the blending ratio of brand coal with relatively high coarse inert content is large. In this case, if the X charcoal is classified as a high inert content charcoal, the X charcoal is pulverized to 3 mm or less and 90 mass% or more. Can not do it.

Therefore, by setting the boundary value of the content of coarse inert to a value between 6.6% and 7.0% (for example, 6.8%), X coal is classified as low inert coal. Further, X-coal is classified as low-coalized coal because vitrinite average reflectance Ro is 0.85%. Moreover, the total expansion coefficient of the blended coal of condition 1 is calculated to be 36.3%. Therefore, since X char is classified into the region 3 of Table 19, the particle size of 3 mm or less may be pulverized at 72 to 78% by mass, and as shown in Table 39, the X coal has a particle size of 3 mm or less of 75% by mass. Crushed with. As a result, the particle size of the blended coal of Condition 1 could be set to 3 mm or less, which is a set value, and 85 mass%.

  Next, even in condition 2, the case where the set particle size of the blended coal is 3 mm or less and 85% by mass will be described as an example.

  Condition 2 is a case where Y charcoal and Z charcoal are blended as brands of coal, and since Z charcoal has a coarse inert content of 3.5%, it is clear that it is a low inert coal, Since the coarse inert content is 5.7% and is in the boundary region of 5 to 7%, it is necessary to set the boundary value.

  Under this condition 2, the blending ratio of Y charcoal is 50%, and the blending ratio of Z charcoal is also 50%. In this case, Y charcoal is classified as low inert coal. Moreover, since the vitrinite average reflectance Ro of Y charcoal is 1.31, it is classified as high coal degree coal. For this reason, since Y charcoal is pulverized with a particle size of 3 mm or less and 82 to 88 mass%, it cannot be adjusted to 3 mm or less and 85 mass%, which is a set value of the blended coal.

Therefore, by setting the boundary value of the content of coarse inert to a value between 5.0% and 5.7% (for example, 5.5%), Y coal is classified as high inert coal.
Therefore, Y charcoal may be pulverized with a particle size of 3 mm or less at 90% by mass or more. Therefore, as shown in Table 39, Y charcoal was pulverized with a particle size of 3 mm or less and 95% by mass. As a result, the particle size of the blended coal under Condition 2 could be set to a set value of 3 mm or less and 85% by mass.

As described above, the boundary value with the coarse inert structure content of 5 to 7% by volume can be appropriately set according to the set particle size of the blended coal.

Claims (2)

Coarse coal having a maximum length of 1.5 mm or more, which is included in coking coal whose particle size is adjusted such that the cumulative percentage of particle size of 3 mm or less is 70 to 80% by mass, as a coking coking coal. Using a boundary value with an inert structure content of 5 to 7% by volume, the high inert content charcoal whose content is higher than the boundary value, and the coarse inert structure content is less than or equal to the boundary value, and vitrinite average reflection A method for producing a coal blend for coke oven charging, which is classified into low inert low-coalized coal with a rate of 0.9% or less and pulverized and blended respectively,
A first step of strongly pulverizing the high inert content charcoal so that a cumulative percentage of a particle size of 3 mm or less is 90% by mass or more;
When the total expansion rate of the entire blended coal is less than 40%, the low inert low-carbonized coal having a total expansion rate of 20% or more has a cumulative percentage of particle size of 3 mm or less of 82 to 88% by mass. The low inert low-carbonized coal having a total expansion rate of less than 20% is pulverized and pulverized so that the cumulative percentage with a particle size of 3 mm or less is 72 to 78% by mass,
When the total expansion rate of the entire blended coal is 40% or more, the low inert low-carbonized coal having a total expansion rate of 20% or more is pulverized so that the cumulative percentage with a particle size of 3 mm or less is 90% by mass or more. The second inert low-coalized coal having a total expansion rate of less than 20% is pulverized so that the cumulative percentage with a particle size of 3 mm or less is 82% by mass or more,
The manufacturing method of the coal blend for coke oven charging characterized by including. The low inert coal with the coarse inert structure content equal to or less than the boundary value is further classified into low inert high coalification coal with a vitrinite average reflectance higher than 0.9%, and pulverized and blended. A method for producing a blended coal for coke oven charging to produce a blended coal,
Furthermore, a third step of pulverizing the low inert high-coalized coal so that the cumulative percentage with a particle size of 3 mm or less is 82% by mass or more and 88% by mass or less,
The manufacturing method of the coal blend for coke oven charging of Claim 1 characterized by the above-mentioned.