JP5686052B2 - Coke production method - Google Patents

Description

  The present invention relates to a method for producing coke, and specifically to a method for producing coke for iron making raw materials.

  When coke used as a raw material for iron making increases in fine powder in the blast furnace, the air permeability important in blast furnace operation deteriorates and the amount of coke used increases. Therefore, it is required to charge coke having a certain particle diameter or more into the blast furnace (block coke) to suppress pulverization of the charged block coke in the blast furnace.

  That is, high-strength coke is desirable because it improves the yield of mass coke production and reduces the amount of coke used in the blast furnace. In addition, against the background of carbon dioxide emissions, there is a need to reduce the amount of carbon used in the blast furnace, and the coke quality level required from that aspect is also increasing. In order to produce high-strength coke, a method that uses more high-quality coal is simple, but this causes problems such as increased production costs and depletion of high-quality coal. There is a limit to the improvement of strength. For this reason, it is important to establish a method for producing high quality coke without relying on good quality coal.

  In addition, high-quality coke can be manufactured without relying on good quality coal, and if the quality satisfies the required quality in the blast furnace, it is possible to mix and use inferior quality coal with lower cost. It is also possible to cope with an increase in manufacturing cost due to the price increase accompanying the depletion and oligopolization of the above-mentioned good quality coal. Thus, also from the viewpoint of suppressing the production cost of coke, establishment of a method for producing high-grade coke without relying on good quality coal is desired.

  Coal used as a raw material for producing coke is charged into a coke oven through a pretreatment process such as particle size adjustment, mixing, and moisture adjustment, and dry-distilled. Of these, in the particle size adjustment, if the packing density (usually indicated on a dry coal basis, hereinafter referred to as “bulk density”) when charging coal into a coke oven is constant, the coal is finely pulverized even in the same composition. It is said that the homogeneity increases and the strength of coke obtained by dry distillation increases. Therefore, if this method can be used, high-strength coke can be produced without using a large amount of high-quality coal.

  However, excessively pulverizing coal causes a decrease in coke strength due to a decrease in coal bulk density, an increase in dust generation during transportation and charging, and an increase in carbon adhering to the coke oven due to an increase in fines. There will be adverse effects on the coke oven operation, such as the resulting deterioration in coke extrudability. For this reason, the coal charged into the coke oven is generally pulverized so that the particle ratio of 3 mm or less is about 70 to 90%.

  Also, since the effect of improving the strength of coke at the time of fine granulation differs depending on the coal brand to be blended, if the coal supplied to the coke oven is uniformly strengthened and pulverized, the desired strength improvement of coke cannot be obtained. In addition, the above-mentioned coke oven operation is adversely affected.

  Coal pulverization particle size is a very important control factor affecting the quality of coke obtained, and coal pulverization methods and coke production methods intended to improve coke quality have been proposed.

  Patent Document 1 discloses a method for producing metallurgical coke, in which two or more types of coal are separately pulverized according to each coal property, and the particle size distribution is adjusted for each coal property. According to the method disclosed in Patent Document 1, it is understood that the pores during solidification after the coal is softened and melted can be controlled. However, even with this method, it is difficult to suppress cracks that occur due to the shrinkage phenomenon after solidification, which strongly affects the strength of coke, so it is difficult to produce high-strength coke by adjusting the particle size by crushing. is there.

  In Patent Document 2, when two or more types of coal are blended, coal containing a coarse inert structure having an absolute maximum length of 1.0 mm or more in the coal exceeding the reference value is finely pulverized from the entire blended coal, and the reference value A method of producing high strength coke by coarsely pulverizing less coal than the entire blended coal is disclosed, and Patent Document 3 discloses the presence of inorganic components present when blending two or more types of coal. Two or more types of coal are pulverized so that the pulverized particle size of coal with a high proportion is smaller than the pulverized particle size of coal with a low proportion of inorganic components, and the proportion of coal particles and inorganic components with a high proportion of inorganic components. Discloses a method for producing high-strength coke by mixing low-coal coal particles, charging into a coke oven, and dry distillation.

JP 11-181441 A JP 2004-83849 A JP 2008-133384 A

  Since the methods disclosed in Patent Documents 2 and 3 are all further subdivided or complicated from the method disclosed in Patent Document 1, there is a possibility that the expected strength improvement effect cannot always be obtained. is there. Moreover, since it takes a lot of time and effort to obtain an index for classifying coal, it is difficult to say that these methods are realistic methods.

  As described above, the conventional technology may not necessarily obtain the expected improvement effect on the quality of coke, and it is very troublesome to quantitatively grasp the index of the coal brand to be selected and pulverized. Requires a lot of time and money.

  The present invention has been made in view of such problems of the prior art, and a plurality of types of coal are pulverized and mixed to form blended coal, and the blended coal is charged into a coke oven to produce coke. In order to produce high-strength coke by adjusting the particle size of the coal to be crushed, specifically, the coal that can increase the strength of the coke by strengthening the degree of pulverization is easily and easily distinguished. Alternatively, the object is to provide a method for producing high-strength coke without significant cost increase.

In the present specification, “coke strength” is a rotational strength index according to the drum method specified in JIS K 2151, and is an abundance ratio (DI of 15 mm or more after 150 rotations, which is most commonly used at present). ¹⁵⁰ abbreviated to ₁₅ ). The strength intended by the present invention is exemplified to be 83.5 DI ¹⁵⁰ ₁₅ or more when the particle size of the blended coal is more than 70% and less than 85% at a particle ratio of 3 mm or less. Increasing the strength of coke by 1 point at DI ¹⁵⁰ ₁₅ also increases the proportion of product coke used for blast furnaces to the same extent. It can be said that it leads to.

The present invention divides a plurality of types of coal into a plurality of series, pulverizes the coals belonging to each series for each series, and then mixes the pulverized coals into a blended coal. In the method for producing coke by charging, coal having an ash content of 9.0% or more (“%” means “mass%” unless otherwise specified) in a plurality of series The coal of the first series which is at least one of the series in which the abundance ratio of the coal is equal to or greater than the abundance ratio of the coal having an ash content of 9.0% by mass or more in the blended coal is pulverized finer than the particle size of the blended coal. it, among a plurality of streams, the presence proportion of the coal ash is 9.0% or more, the ash in the coal blend is at least one of the sequences of sequence is less than the presence ratio of the coal is 9.0% or more coal second series, coal blends Grinding coarser than the particle size, and, blended coal is a coke manufacturing method characterized by having a particle size of particles in the following proportions 3mm is 70 percent less than 85%.

  In the present invention, “ash” means the percentage of the amount of ash remaining when 1 g of a sample of coal is ashed by heating to 815 ° C. in air under the conditions specified in JIS M 8812.

  In this case, among the plurality of series, the coal having an ash content of 9.0% or more is a series in which the ash content in the blended coal is equal to or more than the coal having an ash content of 9.0% or more, and the first series. And pulverizing the third series of coals excluding the same or smaller than the grain size of the blended coal, and coal having an ash content of 9.0% or more in the plurality of series The fourth class coal excluding the second series is the same as the grain size of the blended coal in which the existing ratio is less than the existing ratio of coal having an ash content of 9.0% or more in the blended coal. Further, it is more preferable that the pulverization is coarser than the particle size of the blended coal.

  According to the present invention, a plurality of types of coal are divided into a plurality of series, and coal belonging to each series is pulverized for each series, and then mixed with each series of pulverized coal. When producing coke by charging, the strength of the coke can be increased by adjusting the particle size of the coal to be crushed to produce high-strength coke. Since the coal that can be produced can be easily and easily distinguished and selected, high-strength coke can be produced without a significant increase in cost.

FIG. 1 is a graph showing the relationship between the ash content of coal and the relationship of ΔDI. FIG. 2 is a graph comparing the strength of coke at each level. FIG. 3 is a graph comparing the strength of coke at each level. FIG. 4 is a graph comparing the strength of coke at each level.

DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the accompanying drawings.
Factors affecting the strength of coke, which is a porous brittle material, include the bulk density of coal during dry distillation, the strength of the coal substrate part, and the porosity, which is the volume fraction of the pores that are the space part surrounded by the substrate. Is mentioned.

  Generally, the higher the bulk density of coal during dry distillation, the higher the strength of the resulting coke. Further, regarding the strength of the substrate portion, there is usually no significant difference in coke charged to the blast furnace, and it is said that it is not a controlling factor for the strength of the obtained coke.

  On the other hand, the porosity of coal is calculated including spherical pores and material defects such as cracks, and is affected by the volatile content of the blended coal and the like. Regarding the strength of coke, it is considered that among the pores, it is influenced by material defects such as cracks.

  The present inventors examined in detail the relationship with the strength of coke, focusing on non-coal ash as a new point of view, rather than the coal properties that have been extensively studied so far for improving the strength of coke. . As described above, ash is a substance that remains when coal is ashed by heating.

  Coal usually shows softening and melting phenomenon while generating gas when it is carbonized and the temperature rises, coal particles coalesce to form an amoeba-like network and solidify as the temperature rises further Shows shrinkage phenomenon.

  Since the ash which the present inventors paid attention to is not coaly, it does not show such softening and melting phenomenon. The ash is not present alone in the coal, but is dispersed and incorporated in the coal and inhibits coking of the coal.

  For this reason, a brand with a high ash content has a difference in shrinkage with coal particles of a brand with a low ash content present in the surroundings during the carbonization process. Thought to bring about a decrease in strength.

  It is effective to finely adjust the particle diameter of the coal particles in order to suppress cracks caused by the difference in shrinkage rate. This is because, although the difference in shrinkage rate does not change by reducing the particle diameter, the absolute amount of shrinkage can be suppressed to be small, so that the stress that causes cracks can be relieved, thereby suppressing the occurrence of cracks.

  That is, by finely pulverizing the coal in the coal pulverization process in the coke production process, it is possible to suppress the occurrence of cracks due to the difference in the shrinkage rate of the coal particles, thereby increasing the strength of the coke. .

  However, if all of the multiple types of coal used as the raw material for coke are finely crushed, as described above, the increase in dust generation and the reduction in the bulk density of coal during charging of the coke oven This causes problems such as a decrease in strength.

Therefore, as a result of repeated studies, the present inventors have experimentally verified that a high coke strength improvement effect can be obtained by finely pulverizing a coal brand having a high ash content.
The present inventors targeted 14 types of coal 1-14, changed the particle size so that the particle ratio of 3 mm or less would be 75% and 85%, and pulverized coals 1-14, respectively, A blended coal was obtained by adding 20% to the blended coal. Then, these blended coals were charged into a coke oven to produce coke, and the strength of the obtained coke was measured.

At this time, the bulk density of the coal was kept constant at 760 kg / m ³ . The difference in strength index of coke in the direction in which the particle sizes of coals 1 to 14 become finer was ΔDI, and was used as an effect index at the time of refining. As the properties of the coal used, ash, MF, which is a logarithmic value of the maximum fluidity of coal determined by the fluidity test method specified in JIS M 8801, and the reflectance measurement method of coal structure specified in JIS M 8816 Table 1 summarizes the obtained average maximum reflectance Ro and the obtained intensity index difference ΔDI.

Moreover, the result of plotting the ash content of the used coals 1 to 14 on the horizontal axis and the strength index difference ΔDI on the vertical axis is shown in a graph in FIG.
From the results shown in FIG. 1 and Table 1, it can be seen that the effect of improving the strength of coke is high by finely pulverizing coal having an ash content exceeding 9.0%.

  The present invention is based on the knowledge described above, which is one of the current mainstream coal pulverization methods, and is divided into a plurality of types of coal and mixed for each series, and finally pulverized. This method is applied to a method of blending coal.

  That is, the present invention provides a blended coal having a predetermined particle size by dividing a plurality of types of coal into a plurality of series, pulverizing coal belonging to each series for each series, and then mixing the pulverized coals of each series. It is assumed that this blended coal is charged into a coke oven to produce coke.

  Under this premise, the present invention broadly means that the coal with high ash content is selectively crushed strongly, and conversely, the coal with low ash content is crushed weakly, specifically, a plurality of series. Of these, coals belonging to a series in which the abundance of coal with an ash content of 9.0% or more is equal to or greater than the abundance of coal with an ash content of 9.0% or more in the coal blend is finer than the particle size of the coal blend Pulverizing, among a plurality of series, coal belonging to a series in which the abundance ratio of coal having an ash content of less than 9.0% is equal to or greater than the abundance ratio of coal having an ash content in blended coal of 9.0% or more, By crushing coarser than the particle size of the blended coal, due to the above-mentioned coal pulverization and strengthening, such as increased dust generation and reduced coke strength due to a decrease in the coal bulk density at the time of charging the coke oven High-strength co It is that possible to manufacture the box.

  Here, coal of a series in which the abundance ratio of coal with an ash content of 9.0% or more among the plurality of series is equal to or greater than the abundance ratio of coal with an ash content of 9.0% or more in the blended coal is more than the grain size of the blended coal. Rough grinding is not preferable because the strength of coke is reduced. Further, among a plurality of series, coal of a series having an ash content of 9.0% or more and a coal content with an ash content of 9.0% or more being less than the coal content is smaller than the blended coal particle size. Crushing is not preferable because it does not lead to an improvement in the strength of coke but also causes a loss of grinding power.

  For this reason, the first ratio which is at least one of the series in which the abundance ratio of coal having an ash content of 9.0% or more among the plurality of series is equal to or greater than the abundance ratio of coal having an ash content in the blended coal of 9.0% or more. Grinding coal of the series finer than the grain size of the blended coal, and the presence of coal with an ash content of 9.0% or more among the multiple coals in the blended coal, the presence of coal with an ash content of 9.0% or more It is preferable to pulverize the second series of coal, which is at least one of the series of less than the proportion, coarsely than the particle size of the blended coal, so that the effect of improving the strength of coke can be enjoyed more efficiently. .

  More preferably, among the plurality of series, the ash content of 9.0% or more of the coal is higher than the presence ratio of coal having the ash content of 9.0% or more in the blended coal. It is to refine the pulverization particle size of the series with a higher proportion of coal brands. However, it is not always necessary to finely pulverize the series having the highest abundance of coal having an ash content of 9% or more in this series, and the effect of improving the strength can be obtained.

  In addition, among the series of coals with an ash content of 9.0% or more, the coal brands with an ash content of 9% or more among the series with coal containing less than 9.0% or more of coal with an ash content of 9.0% or more. It is effective to increase the coke strength and to reduce the pulverization power by coarsening the pulverization particle size of the series having a lower abundance ratio.

  For this reason, among the plurality of series, a coal having an ash content of 9.0% or more is a series in which the ash content in the blended coal is equal to or more than a coal having a ash content of 9.0% or more, and the first series is The removed third series of coal is pulverized to be the same as the grain size of the blended coal or finer than the grain size of the blended coal, and the abundance of coal having an ash content of 9.0% or more in the plurality of series Is a series in which the ash content in the blended coal is less than the abundance of coal of 9.0% or more, and the fourth series coal excluding the second series is the same as or blended with the grain size of the blended coal It is preferably coarser than the particle size of charcoal and pulverized.

  In addition, when coal particles are made fine by pulverization, the bulk density when the coal is charged into the coke oven decreases and the strength of the coke decreases. In some cases, the strength of coke may be reduced. In addition, it may be difficult to continue operation due to overloading of the pulverizer used to pulverize coal for the production of coke, and fine pulverization occurs due to fine pulverization. The coal should not be overly fine because it tends to generate dust and is undesirable in the working environment.

  In addition, since a plurality of types of coal are usually blended when producing coke, if the coal to be blended is coarsely pulverized, the homogeneity of the obtained coke may be impaired, and the strength of the coke may be reduced.

  For the above reasons, it is preferable to adjust the particle size of the coals in each of the plurality of coals so that the particle ratio of 3 mm or less, which is a particle size index for which coal blend is normally used, has a particle size of more than 70% and less than 85%.

  Of the properties of coal shown in Table 2 (of ash, MF, Ro, and the fine structure components included in the fine structure component group of inertite determined by the method of measuring the fine structure components of coal defined in JIS M 8816, The pulverization conditions were determined using four brands of coal A, B, C and D having TI, which is a total inert expressed by adding 1/3 of the abundance to the abundance of minerals. Coke was produced with various changes. As a pretreatment of coal in production, four brands of coals A to D were pulverized in two pulverization systems separately and then mixed. The coal particle size after mixing was measured, and the bulk density for filling the coal was determined based on the relationship between the particle size and the bulk density obtained in advance.

  A 50 kg scale test carbonization furnace was used for carbonization, and coal filled in an iron carbonization container with a predetermined bulk density was charged into the test carbonization furnace and carbonized at 1080 ° C. for 18 hours. The coke was discharged in a red hot state and then cooled in a nitrogen atmosphere, and the rotational strength index of the coke was determined based on the method defined in JIS K 2151.

  In this example, 30% and 20% of coal A and B having an ash content of 9% or more are blended, respectively, and 30% and 20% of coal C and D having an ash content of less than 9% are blended, respectively, and the ash content is 9%. Coke was produced as a blended composition in which the above coals A and B account for 50% of the total.

  Table 3 shows the blending ratio of coals A to D for each test, the abundance ratio of coals A and B with an ash content of 9% or more with respect to the total blended coal, and the coals A and B in series 1 and 2 pulverized together. The abundance ratio, the pulverized particle size of series 1 and 2, the particle size of the entire blended coal, the bulk density at the time of coal filling, and the strength of the obtained coke are shown together.

  Moreover, in FIG. 2, the intensity | strength of the coke obtained by this invention examples 1-4 which satisfy | fill the range of this invention, and the comparative examples 1-3 which do not satisfy the range of this invention is shown with a graph.

  Inventive Examples 1 to 4 and Comparative Examples 1 to 3 in Table 3 and FIG. 2 will be briefly described.

(Invention Example 1)
Invention Example 1 pulverizes coals A and B having an ash content of 9% or more so that the ratio of 3 mm or less is 85% in the same series, and coals C and D having an ash content of less than 9% in the same series. And then pulverized so that the ratio of 3 mm or less becomes 75%, and after that, the blended coal obtained by mixing both series of coals is packed under the condition that the total particle size is 80% at a ratio of 3 mm or less and the bulk density is 760 kg / m ^3. And carbonized.

  That is, in Example 1 of the present invention, when the series obtained by pulverizing the coals A and B is set as the series 1 and the series obtained by pulverizing the coals C and D is set as the series 2, the coal A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A and B having an ash content of 9% or higher with respect to 50%, which is higher than 100% in the series, is pulverized more finely than the grain size of the blended coal, and the coal A having an ash content of 9% or higher. , B is an example of the present invention in which series 2 having a low 0% in the series is pulverized coarsely than the grain size of the blended coal and dry-distilled.

(Invention Example 2)
Invention Example 2 pulverizes coals A and B having an ash content of 9% or more so that the ratio of 3 mm or less is 76% in the same series, and coals C and D having an ash content of less than 9% in the same series. Then, the mixture is pulverized so that the ratio of 3 mm or less is 66%, and then the blended coal obtained by mixing both series of coals is packed under the condition that the total particle size is 3 mm or less and the bulk density is 71% and the bulk density is 776 kg / m ^3. And carbonized.

  That is, in Example 2 of the present invention, when the series obtained by pulverizing the coals A and B is set as the series 1 and the series obtained by pulverizing the coals C and D is set as the series 2, the coal A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A, B having an ash content of 9% or more is pulverized more finely than the particle size of the blended coal, and the coal A having an ash content of 9% or more. This is an example of the present invention in which series 2 having B as low as 0% in the series is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Invention Example 3)
Invention Example 3 pulverizes coals A and B having an ash content of 9% or more in the same series so that the ratio of 3 mm or less is 88% and coals C and D having an ash content of less than 9% in the same series. The mixture is pulverized so that the ratio of 3 mm or less is 80%, and then, the total particle size of the blended coal obtained by mixing both series of coals is 3% or less at a ratio of 84% and the bulk density is 751 kg / m ^3. Carbonized.

  In other words, in Example 3 of the present invention, when the series obtained by pulverizing the coals A and B is set as the series 1 and the series obtained by pulverizing the coals C and D is set as the series 2, the coal A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A, B having an ash content of 9% or more is pulverized more finely than the particle size of the blended coal, and the coal A having an ash content of 9% or more. This is an example of the present invention in which series 2 having B as low as 0% in the series is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Invention Example 4)
Invention Example 4 pulverizes coal A having an ash content of 9% or more and coal D having an ash content of less than 9% so that the ratio of 3 mm or less is 85% in the same series and coal B having an ash content of 9% or more. Coal C with an ash content of less than 9% is pulverized so that the ratio of 3 mm or less in the same series is 75%, and then the total particle size of the blended coal obtained by mixing both series of coal is 80% in a ratio of 3 mm or less. The bulk density was 760 kg / m ^{3 and} the mixture was dry-distilled.

  That is, in Example 4 of the present invention, when the series obtained by pulverizing the coals A and D is set as the series 1 and the series obtained by pulverizing the coals B and C is set as the series 2, the coal A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A having an ash content of 9% or more is pulverized more finely than the grain size of the blended coal, and the coal B having an ash content of 9% or more is the series. This is an example of the present invention in which series 2 as low as 40% is coarsely pulverized from the particle size of the blended coal and dry-distilled.

(Comparative Example 1)
In Comparative Example 1, coals A and B and coals C and D were pulverized in separate series, but the particle size after pulverization was pulverized so that the ratio of 3 mm or less in both series was equal to 80%, and then both The total particle size of the blended coal mixed with the coal of the series was 80% at a ratio of 3 mm or less and the bulk density was dry-distilled under conditions of 760 kg / m ³ .

  That is, in Comparative Example 1, assuming that a series obtained by pulverizing coals A and B is set as series 1 and a series obtained by pulverizing coals C and D is set as series 2, coals A and B having an ash content of 9% or more with respect to the entire blended coal. Compared to 50%, coal A and B with ash content of 9% or higher is 100% within the series, and coal A and B with ash content of 9% or higher is low with 0% within the series. Series 2 is also a comparative example that is pulverized to the same particle size as the blended coal and dry-distilled.

(Comparative Example 2)
In Comparative Example 2, coals A and B and coals C and D were pulverized in separate series, but the pulverized grain size was pulverized so that the ratio of 3 mm or less in both series was equal to 71%, and then both The total particle size of the blended coal mixed with the coal of the series was also filled at a rate of 3 mm or less at 71% and the bulk density of 776 kg / m ³ and dry-distilled.

  That is, in Comparative Example 2, assuming that the series obtained by pulverizing coals A and B is set as series 1 and the series obtained by pulverizing coals C and D is set as series 2, coal ash having an ash content of 9% or more with respect to the entire blended coal is obtained. Compared to 50%, coal A and B with ash content of 9% or higher is 100% within the series, and coal A and B with ash content of 9% or higher is low with 0% within the series. Series 2 is also a comparative example that is pulverized to the same particle size as the blended coal and dry-distilled.

(Comparative Example 3)
In Comparative Example 3, coals A and B and coals C and D were pulverized in separate series, but the pulverized particle size was pulverized so that the ratio of 3 mm or less in both series was equal to 84%, and then both The total particle size of the blended coal in which the coals of the series were mixed was also filled at a ratio of 3 mm or less at 84% and the bulk density was 751 kg / m ³ and dry-distilled.

  That is, in Comparative Example 3, assuming that the series obtained by pulverizing coals A and B is set as series 1 and the series obtained by pulverizing coals C and D is set as series 2, coal ash with an ash content of 9% or more of the entire blended coal is obtained. Compared to 50%, coal A and B with ash content of 9% or higher is 100% within the series, and coal A and B with ash content of 9% or higher is low with 0% within the series. Series 2 is also a comparative example that was pulverized to the same particle size as the blended coal and dry-distilled.

  As shown in the graph of FIG. 2, any particle size of Invention Example 2 and Comparative Example 2, Invention Examples 1 and 4 and Comparative Example 1, Invention Example 3 and Comparative Example 3 are the same. However, since the strength of the coke of the example of the present invention exceeded the strength of the coke of the comparative example by 0.2 to 1.2 points, it was confirmed that the present invention has a clear effect.

  In the same manner as in Example 1, coals A and B having an ash content of 9% or more, coals C and D having an ash content of less than 9%, and coals A and B having an ash content of 9% or more occupy 55% of the total. Thus, coke was produced as a blended coal.

  Table 4 shows the blending ratio of each brand of coals A to D, the abundance ratio of coals A and B with an ash content of 9% or more, and the presence of coal in series 1 and 2 pulverized together. A ratio, the grinding | pulverization particle size of each series 1 and 2, the particle size of the whole blended coal, the bulk density at the time of coal filling, and the intensity | strength of the obtained coke are shown collectively.

  FIG. 3 shows the strength of coke obtained in Invention Examples 5 and 6 that satisfy the scope of the present invention and Comparative Examples 4 and 5 that do not satisfy the scope of the present invention.

  The invention examples 5 and 6 and the comparative examples 4 and 5 in Table 4 and FIG. 3 will be briefly described below.

(Invention Example 5)
Invention Example 5 pulverizes coals A and B having an ash content of 9% or more in the same series so that the ratio of 3 mm or less is 85% and coals C and D having an ash content of less than 9% in the same series. The mixture is pulverized so that the ratio of 3 mm or less becomes 74%, and then the blended coal obtained by mixing both series coals is filled at a ratio of 80% and a bulk density of 760 kg / m ^{3 in} a ratio of 3 mm or less. Carbonized.

  That is, in Example 5 of the present invention, when the series obtained by pulverizing coals A and B is set as series 1, and the series obtained by pulverizing coals C and D is set as series 2, coals A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A, B having an ash content of 9% or more is pulverized more finely than the particle size of the blended coal, and the coal A having an ash content of 9% or more. This is an example of the present invention in which series 2 having B as low as 0% in the series is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Invention Example 6)
In Example 6 of the present invention, coal A having an ash content of 9% or more and coal D having an ash content of less than 9% are pulverized in the same series so that the ratio of 3 mm or less is 85%, and coal B having an ash content of 9% or more. And coal C with an ash content of less than 9% is pulverized so that the ratio of 3 mm or less in the same series is 76%, and then the total particle size of the blended coal in which both series of coal is mixed is 80% in a ratio of 3 mm or less. Then, it was filled and dry-distilled under the condition that the bulk density was 760 kg / m ³ .

  That is, in Example 6 of the present invention, when the series obtained by pulverizing coals A and D is set as series 1 and the series obtained by pulverizing coals B and C is set as series 2, coal A, B having an ash content of 9% or more with respect to the entire blended coal. The coal A having an ash content of 9% or more is pulverized more finely than the particle size of the blended coal, and the coal B having an ash content of 9% or more. This is an example of the present invention in which series 2 having a low 36.4% in the series is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Comparative Example 4)
In Comparative Example 4, coals A and B and coals C and D were pulverized in separate series, but the pulverized particle size was pulverized so that the ratio of 3 mm or less was equal to 80% in both series. The total particle size of the blended coal mixed with the coal of the series was 80% at a ratio of 3 mm or less and the bulk density was dry-distilled under conditions of 760 kg / m ³ .

  That is, in Comparative Example 4, when the series in which coals A and B are pulverized is set as series 1 and the series in which coals C and D are pulverized is set as series 2, coal ash with an ash content of 9% or more for the entire blended coal Coal A and B with an ash content of 9% or higher and 100% in the series, which is higher than 55%, which is a proportion of 55%, Coal A and B with an ash content of 9% or higher are as low as 0% in the series. Series 2 is also a comparative example that is pulverized to the same particle size as the blended coal and dry-distilled.

(Comparative Example 5)
In Comparative Example 5, coal A having an ash content of 9% or more and coal D having an ash content of less than 9% are pulverized so that the ratio of 3 mm or less is 74% in the same series, and coal B having an ash content of 9% or more Coal C with an ash content of less than 9% is ground in the same series so that the ratio of 3 mm or less is 85%, and then the total particle size of the blended coal obtained by mixing both series of coal is 80% in a ratio of 3 mm or less. The bulk density was 760 kg / m ^{3 and} the mixture was dry-distilled.

  That is, in Comparative Example 5, when the series in which coals A and D are pulverized is set as series 1 and the series in which coals B and C are pulverized is set as series 2, the ash content of the coal blend as a whole is 9% or more. Coal A with an ash content of 9% or more, compared to 55%, which is a ratio, pulverizes the series 1 which is as high as 77.8% within the series coarsely than the particle size of the blended coal, and coal B with an ash content of 9% or more This is a comparative example in which Series 2 having a low 36.4% in the series was pulverized finer than the coal blend particle size and dry-distilled.

  As shown in the graph of FIG. 3, in the inventive examples 5 and 6 and the comparative examples 4 and 5 in which the particle sizes of the blended coals are the same, the strength of the coke of the inventive example is 0.3 to 1. Since it exceeded 4 points, it was confirmed that the present invention has a clear effect.

  In the same manner as in Examples 1 and 2, 25% and 15% of coals A and B having an ash content of 9% or more were blended, respectively, and 35% and 25% of coals C and D having an ash content of less than 9% were blended, respectively. In addition, coke was produced with a composition in which coal with an ash content of 9% or more accounted for 40% of the total.

  Table 5 shows, for each test, the blending ratio of each coal A to D, the abundance ratio of coal A and B with an ash content of 9% or more to the entire blended coal, coal A and B in series 1 and 2 pulverized together The abundance ratio, the pulverization particle size of each series 1 and 2, the particle size of the entire blended coal, the bulk density at the time of coal filling, and the strength of the obtained coke are shown together.

  FIG. 4 is a graph showing the strength of coke obtained in Examples 7 and 8 of the present invention that satisfy the scope of the present invention and Comparative Examples 6 and 7 that do not satisfy the scope of the present invention.

  The invention examples 7 and 8 and comparative examples 6 and 7 in Table 5 and FIG. 4 will be briefly described below.

(Invention Example 7)
Invention Example 7 pulverizes coals A and B having an ash content of 9% or more in the same series so that the ratio of 3 mm or less is 85% and coals C and D having an ash content of less than 9% in the same series. The mixture is pulverized so that the ratio of 3 mm or less becomes 77%, and then the blended coal obtained by mixing both series of coals is packed under the condition that the total particle size is 80% and the bulk density is 760 kg / m ³ at a ratio of 3 mm or less. Carbonized.

  That is, in Example 7 of the present invention, when the series obtained by pulverizing coals A and B is set as series 1, and the series obtained by pulverizing coals C and D is set as series 2, coals A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A having an ash content of 9% or more is pulverized more finely than the grain size of the blended coal, and the coal B having an ash content of 9% or more is the series. This is an example of the present invention in which series 2 having a low value of 0% is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Invention Example 8)
Invention Example 8 pulverizes coal A having an ash content of 9% or more and coal D having an ash content of less than 9% so that the ratio of 3 mm or less is 85% and coal B having an ash content of 9% or more. And coal C with an ash content of less than 9% is pulverized so that the ratio of 3 mm or less in the same series is 75%, and then the total particle size of the blended coal obtained by mixing both series of coal is 80% in a ratio of 3 mm or less. Then, it was filled and dry-distilled under the condition that the bulk density was 760 kg / m ³ .

  That is, in Example 8 of the present invention, when the series obtained by pulverizing the coals A and D is set as the series 1 and the series obtained by pulverizing the coals B and C is set as the series 2, the coal A and B having an ash content of 9% or more with respect to the entire blended coal. The coal A having an ash content of 9% or more is pulverized more finely than the grain size of the blended coal, and the coal B having an ash content of 9% or more is the series. This is an example of the present invention in which the series 2 as low as 30% is pulverized coarsely than the particle size of the blended coal and dry-distilled.

(Comparative Example 6)
In Comparative Example 6, coals A and B and coals C and D were pulverized in separate series, but the pulverized particle size was pulverized so that the ratio of 3 mm or less was 80%, and then both pulverized. The total particle size of the blended coal mixed with the coal of the series was 80% at a ratio of 3 mm or less and the bulk density was dry-distilled under conditions of 760 kg / m ³ .

  That is, in Comparative Example 6, assuming that a series obtained by pulverizing coals A and B is set as series 1 and a series obtained by pulverizing coals C and D is set as series 2, coal ash having an ash content of 9% or more with respect to the entire blended coal is obtained. Compared to 40%, coal A and B with an ash content of 9% or higher is 100% in the series, while coal 1 and coal A and B with an ash content of 9% or higher are as low as 0% in the series. Series 2 is also a comparative example that is pulverized to the same particle size as the blended coal and dry-distilled.

(Comparative Example 7)
In Comparative Example 7, coal A having an ash content of 9% or more and coal D having an ash content of less than 9% are pulverized so that the ratio of 3 mm or less is 75% in the same series and coal B having an ash content of 9% or more Coal C with an ash content of less than 9% is ground in the same series so that the ratio of 3 mm or less is 85%, and then the total particle size of the blended coal obtained by mixing both series of coal is 80% in a ratio of 3 mm or less. The bulk density was 760 kg / m ^{3 and} the mixture was dry-distilled.

  That is, in Comparative Example 7, when the series in which coals A and D are pulverized is set as series 1 and the series in which coals B and C are pulverized is set as series 2, the ash content of the blended coal as a whole is 9% or more. Compared to 40%, coal A with an ash content of 9% or more pulverizes the series 1 which is 50% high in the series, finer than the particle size of the blended coal, and coal B with an ash content of 9% or more in the series This is a comparative example in which series 2 as low as 30% was coarsely pulverized from the particle size of the blended coal and dry-distilled.

  As shown in the graph of FIG. 4, in Examples 7 and 8 and Comparative Examples 6 and 7 in which the particle sizes of the blended coals are the same, the strength of the coke of the present invention example is 0.2 to Since it exceeded 0.9 points, it was confirmed that the present invention has a clear effect.

Claims (2)

Divide multiple types of coal into multiple series, pulverize the coal belonging to each series for each coal, then mix the pulverized coals into blended coal, and charge the blended coal into the coke oven In the method for producing coke,
Among the above-mentioned series, the ash content defined as a percentage of the amount of ash remaining when 1 g of a coal sample is heated to 815 ° C. in air under the conditions limited to JIS M 8812 and incinerated. Coal of the first series that is at least one of the series in which the abundance ratio of coal of 9.0% by mass or more is equal to or greater than the abundance ratio of coal in which the ash content in the blended coal is 9.0% by mass or more Pulverizing finer than the particle size of the blended coal ,
Among the plurality of series, at least one of the series in which the coal having an ash content of 9.0% by mass or more is less than the coal having an ash content of 9.0% by mass or more in the blended coal. Crushing a second series of coal, which is one series, coarser than the grain size of the blended coal ; and
The method for producing coke, wherein the blended coal has a particle size such that a particle ratio of 3 mm or less is more than 70% by mass and less than 85% by mass . Among the plurality of series, the abundance ratio of the coal having an ash content of 9.0% by mass or more is a series in which the ash content in the blended coal is equal to or greater than the abundance ratio of the coal having a mass ratio of 9.0% by mass and more. Crushing the third series of coals excluding the first series to be the same as the grain size of the blended coal or finer than the grain size of the blended coal, and among the plurality of series, the ash content is 9 A fourth series excluding the second series, wherein the coal is present at a mass ratio of 0.0 mass% or more and the ash content in the blended coal is less than the mass ratio of coal at 9.0 mass% or more. the coal, in the same particle size of the coal blend or coarser than the particle size of the coal blend, process for the preparation of coke claim 1, characterized in that the grinding.

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