JP2006291190A - Caking filler having excellent strength-increasing characteristics and method for producing highly strong coke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a caking filler which can ensure a strength of ≥84.5 at DI<SP>150</SP><SB>15</SB>, even when the rate of low caking coal and/or fine non-caking coal occupied in coal of raw material exceeds 20% on the production of coke for blast furnaces, and to provide a method for producing the coke, by which the highly strong coke can be produced with the caking filler. <P>SOLUTION: This caking filler which is compounded with coal of raw material for producing highly strong coke and has excellent strength-increasing characteristics is characterized by comprising 20 to 90 % of a hexane-soluble component (HS component), ≤1 % of a toluene-insoluble component (TI component), and the remainder of a hexane-insoluble and toluene-soluble component (HITS component) and an inevitable residual component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a caking filler that acts to enhance the strength of coke, and more particularly to a method for producing high-strength coke using a petroleum heavy fraction.

  In blast furnace operation, the reducing material coke is required to have a required strength in order to ensure air permeability in the furnace. In order to produce high-strength coke, high-quality strong caking coal is required as coking coking coal, but the high-quality caking coal is in a resource-depleted state for a long time.

  Therefore, many methods have been proposed so far for producing high-strength coke using low-quality non-coking coal as raw coal.

  When using low quality non-caking coal as raw coal, caking filler is added and mixed in order to compensate for caking properties. For example, tar, pitch, petroleum-based caking material, or the like is used as caking filler (see Patent Documents 1 to 3).

  In Patent Document 1, a petroleum-based heavy fraction such as asphalt is added to raw coal, the blending ratio of caking coal is reduced, the blending ratio of non-caking coal is increased, and high-quality coke is produced. A method is disclosed.

  In Patent Document 2, asphalt having a softening point of 100 ° C. or higher obtained from petroleum heavy oil using butane, pentane or hexane as a solvent alone or in combination is used as a raw coal. A method for producing coke to add and mix parts by weight is disclosed.

However, with these manufacturing methods, the coke strength index DI ¹⁵⁰ ₁₅ cannot achieve 84.5 or more, which is the minimum required for blast furnace coke. Further, the blending ratio of non-slightly caking coal is as low as 0% in Patent Document 1 and 9 to 13% in Patent Document 2.

  Accordingly, the present applicant aims to produce high-strength coke for blast furnaces, and in Patent Document 3, a heavy tar fraction is added as a caking filler to coking coal containing 0-60 wt% of non-minor caking coal. A method for producing coke for blast furnace was proposed.

In this production method, tar is distilled at 200 to 350 ° C., hexane-soluble content (HS) is 20 wt% or less, components insoluble in hexane and soluble in toluene (HITS) are 40 to 80 wt%, insoluble in toluene. For heavy blast furnaces where DI ¹⁵⁰ ₁₅ is 83-84 in a high range of 40-60% when the heavy tar fraction with component (TI) adjusted to 0-40 wt% is used. Coke production is possible.

However, even in the above production technique, coke having a large amount of non-slightly caking coal and having DI ¹⁵⁰ ₁₅ of 84.5 or more cannot be produced.

Therefore, there is a strong demand for a coke production technique that can sufficiently and reliably ensure a coke strength of 84.5 or more with DI ¹⁵⁰ ₁₅ even when a large amount of non-slightly caking coal is used.

  In addition, as one of the methods to obtain high-strength coke by using a large amount of non-slightly caking coal, the coal is dried before charging into the coke oven, and the bulk density of the coal charged into the coke oven is improved. A process called a humidified coal method is widely used in Japan (see Patent Document 4). However, in the modified coal method, a caking filler that effectively improves coke strength, and the caking supplement There is no known production method capable of producing high-strength coke using a material.

  Petroleum heavy fraction (for example, deasphalted asphalt) is a by-product that is produced as a by-product when light oil is separated and refined from crude oil. Conventionally, the majority of petroleum heavy fractions have been used as fuel, but since heavy metal components such as sulfur and vanadium in crude oil of petroleum heavy fractions are concentrated at high concentrations, they are discharged. Combustion equipment that takes measures against high temperature corrosion using a smoke desulfurization apparatus or vanadium is required, and further, there is an environmental problem that combustion ash waste containing heavy metals pollutes the environment.

  On the other hand, when petroleum heavy fraction is used in the coke production process as a caking filler for blended raw materials, pyrolysis gas (due to the sulfur component in the caking filler) generated during coke production ( Even if the sulfur concentration in the coke oven gas) is increased, it is desulfurized by the accompanying coke oven gas refining equipment, which is advantageous in terms of equipment costs. However, there is a concern that heavy metal components such as sulfur components and vanadium remain in the coke due to sulfur components in the caking filler and vanadium and other heavy metal components.

  Most of the heavy metal components such as sulfur components and vanadium remaining in the coke are transferred to the slag generated in the blast furnace when the coke is used in the blast furnace, and are removed and separated from the hot metal. For this reason, as the quality of coke for blast furnace, it is required that the residual amount of heavy metal components such as sulfur components and vanadium in coke is transferred into slag in the blast furnace and the quality of components in hot metal is not deteriorated.

  In addition, when petroleum heavy fractions are used in the coke production process as a caking filler for blended raw materials, caking filler is used for the production of molten iron in the blast furnace as part of the blast furnace coke. In addition, they are effectively used as chemical raw materials and fuels, respectively, as part of the oil and pyrolysis gas generated in the coke process.

  Therefore, when producing coke, using petroleum heavy fraction as a caking filler for blended raw materials, especially when blended coal with a high blending ratio of non-slightly caking coal is used, However, there is a demand for a production method for producing coke that has high coke strength and good quality that does not affect the quality of hot metal in a blast furnace due to residual heavy metal components such as sulfur and vanadium in the coke.

Coal chemistry and industry (Sankyo Publishing Co., Ltd., 1977 edition, p.315) JP 59-179586 A JP-A-9-241653 Ferrum Vol. 9 (2004), p. 810

In view of the above-mentioned demand, the present invention can secure a strength of 84.5 or more with DI ¹⁵⁰ ₁₅ even when the blending ratio of non-slightly caking coal in the raw coal exceeds 20% in the production of coke for blast furnace. It is a first object to provide a caking filler and a production method capable of producing a high-strength coke using the caking filler.

  In addition, the present invention has an effect on the quality of hot metal in a blast furnace due to the residue of heavy metal components such as sulfur components and vanadium in coke when producing coke using a heavy petroleum-based fraction as a caking filler for blended raw materials. It is a second object to provide a production method for producing coke having good quality without any problems.

  As the proportion of non-slightly caking coal in the coking coal increases, the caking property as coking coal naturally decreases. It is necessary to add a predetermined amount of the binding filler to the raw coal.

  As described above, petroleum-based heavy fractions (for example, deasphalted asphalt) and tar heavy fractions effectively act as caking fillers that increase the strength of coke. However, in the case of using a large amount of non-slightly caking coal, or when using various types of non-slightly caking coal, it is necessary to use caustic supplementation in order to bring out the strength enhancement effect of the caking filler. It is necessary to know the properties of the material and to select and blend a caking filler material that matches the properties of the raw coal.

  The present inventor, as a caking filler, is insoluble in toluene among residues after squeezing light components from petroleum (SDA [Solvent Deasphalting] pitch, solvent escape pitch; hereinafter referred to as “SDA pitch”). Focusing on the SDA pitch whose component (hereinafter also referred to as “TI component”) is extremely small as 1% or less, the effect of increasing the strength was investigated.

As a result, even if the blending amount of the non-slightly caking coal is increased, the present inventor, if a predetermined amount of SDA pitch having a TI component of 1% or less is blended as a caking filler, DI ¹⁵⁰ ₁₅ is 84.5. It has been found that the above high strength coke can be produced.

  This invention was made | formed based on the said knowledge, and the summary is as follows.

  (1) A caking filler compounded in raw coal to produce high-strength coke, which is soluble in hexane (HS component): more than 20% but not more than 90%, and insoluble in toluene (TI) Ingredient): 1% or less, and the balance consists of a component insoluble in hexane and soluble in toluene (HITS component) and an inevitable residual component, and a caking filler excellent in strength enhancement characteristics.

  (2) The caking filler having excellent strength enhancement characteristics as described in (1) above, wherein the raw coal includes more than 20% by mass of non-slightly caking coal.

  (3) The caking filler having excellent strength enhancement characteristics as described in (1) or (2) above, wherein the caking filler is a petroleum solvent degreasing pitch.

  (4) The overall expansion rate of the coking coal (weighted average of the total expansion rate) is 30 to 100%, which is excellent in strength enhancement characteristics according to any one of (1) to (3) Caking filler.

  (5) The caking filling with excellent strength enhancement characteristics according to any one of (1) to (4), wherein the volatile content of the raw coal is 22.5 to 32.5 dry% Wood.

  (6) In the method of producing high-strength coke by dry distillation of raw coal, hexane-soluble component (HS component): more than 20% and 90% or less, and toluene-insoluble component (TI component) ) Production of high strength coke characterized by containing a caking filler containing 1% or less, the balance being insoluble in hexane and soluble in toluene (HITS component) and inevitable residual components Method.

  (7) The method for producing high-strength coke according to (6), wherein the raw coal includes more than 20% by mass of non-slightly caking coal.

  (8) The method for producing high-strength coke according to (6) or (7) above, wherein the coking coal has a total expansion coefficient (weighted average of total expansion coefficient) of 30 to 100%.

  (9) The method for producing high-strength coke according to any one of (6) to (8), wherein a volatile content of the raw coal is 22.5 to 32.5 dry%.

  (10) The method for producing high-strength coke according to any one of (6) to (9), wherein the caking filler is blended in an amount of 5% by mass or less based on raw coal.

  (11) The method for producing high-strength coke according to any one of (6) to (9), wherein the caking filler is blended in an amount of 2% by mass or less based on raw coal.

  (12) The method for producing high-strength coke according to any one of (6) to (9), wherein the caking filler is blended in an amount of 0.2 to 0.8 mass% with respect to the raw coal. .

  (13) The method for producing high-strength coke according to any one of (6) to (12), wherein the caking filler is a petroleum solvent degreasing pitch.

According to the present invention, a high strength coke of 84.5 or more can be produced with DI ¹⁵⁰ ₁₅ by blending SDA pitch having a TI component of 1% or less into the raw coal as a caking filler. In addition, the present invention can effectively use a petroleum heavy fraction generated in large quantities when separating and refining light oil from crude oil as a caking additive, and can produce high-strength coke for blast furnaces. In this respect, it not only has great industrial value, but also has great social significance in terms of environmental protection.

  The present invention will be described in detail. SDA pitch is mainly composed of a component soluble in hexane (hereinafter sometimes referred to as “HS component”), a component insoluble in hexane and soluble in toluene (hereinafter sometimes referred to as “HITS component”), and toluene. It consists of an insoluble component (TI component) and other inevitable residual components.

  FIG. 1 is a composition diagram in which the composition of the HS component, the HITS component, and the TI component is taken on each side. The present inventor, as a caking filler material, shows the region surrounded by the solid line in FIG. The SDA pitch in the “1-D” region), that is, “the SDA pitch having an extremely small TI component of 1% or less” was noted. First, the reason will be described.

  In order to ensure high strength, in the pore structure of coke, (a) the pore size is appropriate, (b) the pore shape is rounded, and (c) the coke wall is thick. Importantly, the inventor has experimentally confirmed that each component generally performs the following actions.

  (A) The HS component (light component) is gasified during the dry distillation process, promotes the growth and coalescence of bubbles in the softened and melted coal, and increases the pore size to an appropriate size (pore expansion action).

  (B) The HITS component (intermediate component) reduces the viscosity of the coal softened and melted during the dry distillation process, and makes the shape of the bubbles round (pore rounding action).

  (C) The TI component (heavy component) is almost a residue, but thickens the coke wall (wall thickness increasing action).

As described above, the TI component contributes to the enhancement of the coke strength by the wall thickness increasing action, but the present inventor further has a blending ratio of the non-slightly caking coal in the raw coal exceeding 20%, and DI. It was experimentally confirmed that in the case of manufacturing conditions that ensure a strength of 84.5 or more at ¹⁵⁰ ₁₅ , the contribution of the wall thickness increasing action to the strength is not necessarily large.

In the case of manufacturing conditions in which DI ¹⁵⁰ ₁₅ ensures a strength of 84.5 or more, the reason why the action of the TI component is not large is that in the case of coke having such a high strength, the wall thickness of the coke is already sufficiently thick, This is probably because the effect of increasing the wall thickness due to the caking filler cannot be expected.

  Moreover, when the blending ratio of the non-slightly caking coal in the raw coal exceeds 20%, the reason why the action of the TI component is not large is that when the blending ratio of the non-slightly caking coal increases, the expansion of the entire blended coal This is considered to be because the pore expanding effect and the pore rounding effect by the HS component and the HITS component other than the TI component are relatively increased.

  The inventors of the present invention have found that the coke strength can be reliably and sufficiently increased by using the SDA pitch in the region surrounded by the solid line (the region of the symbol “1-D”) in FIG.

  Below, an example is shown about the specific manufacturing method (The specific method of manufacturing petroleum pitch by carrying out the solvent extraction process of petroleum heavy oil) of the SDA pitch of the range of "1-D".

  Using propane, butane, pentane, hexane, or heptane alone or as a mixture, extraction is performed at a volume flow rate ratio of the solvent to petroleum heavy oil (solvent flow / petroleum heavy oil) of 2 or more.

  The larger the volume flow rate ratio, the more preferable it is because the paraffin in the raw heavy oil is selectively extracted and concentrated to light oil. However, if it is excessively large, the scale of the equipment such as the extraction tower must be increased. Not only can it be obtained, but a large amount of power and fuel (utility) are required for heating, cooling, compressing and transferring the solvent, and the economic efficiency is lowered.

  Therefore, the extraction is preferably performed at a volume flow ratio of 2 to 10, more preferably 4 to 6.

  The temperature of the extraction treatment may be any temperature at which the extraction operation can be suitably performed, but is preferably performed in the vicinity of the critical temperature of the solvent or a mixture thereof, more preferably below the critical temperature (subcritical). The extraction treatment is performed at a pressure not higher than the critical pressure of the solvent or a mixture thereof.

  In the above range, an SDA pitch in the range of 1-D can be obtained by suitably selecting the extraction conditions.

  The HS component was specified to include more than 20% and 90% or less in anticipation of strength enhancement by the pore expanding action. If the HS component is 20% or less, the effect of enhancing the strength due to the above action cannot be obtained. On the other hand, if it exceeds 90%, the pores become too large, and conversely, the coke strength decreases. Preferably, it is 30 to 60%.

  Since the content of the HITS component is determined from the content of the HS component and the TI component as shown in FIG. The HITS component has a significant pore rounding action within the content range shown in FIG. 1, and greatly contributes to the enhancement of strength.

Next, the present inventor changed the HS component: 31.3%, the TI component: 0.3%, the HITS component and the unavoidable residual component: the remaining SDA pitch, and changed the blending amount to make non-slightly caking. The coking strength (DI ¹⁵⁰ ₁₅ ) was measured by blending with raw coal containing 40% charcoal. The result is shown in FIG.

As can be seen from FIG. 2, when the minimum required coke strength (DI ¹⁵⁰ ₁₅ ) is 84.5, in order to secure 84.5 or more, the SDA pitch must be blended within 5% or less. . Moreover, it turns out that the direction which reduced the compounding quantity improves coke strength.

  Furthermore, it can be seen from FIG. 2 that the more preferable amount of SDA pitch is 2% or less, and the more preferable amount is 0.2 to 0.8%.

  The reason why the coke strength decreases when it exceeds 5% is that the pore expanding effect and the pore rounding action are too effective, and the pores become too large. Too large pores act as defects in the coke and reduce coke strength. Further, the reason why the coke strength is not improved at less than 0.2% is that the amount of the caking filler is insufficient to exhibit a sufficient pore expanding effect and pore rounding action.

  In addition, when petroleum heavy fractions are used in the coke production process as a caking additive for blended raw materials, sulfur components in crude oil and heavy metal components such as vanadium are present in the petroleum heavy fractions. Since it is concentrated at a high concentration, there is a concern that it may remain in these cokes.

  About half of the sulfur component in the caking filler is transferred to the pyrolysis gas (coke oven gas) in the coke oven, and desulfurized by the accompanying coke oven gas purification equipment. On the other hand, most of heavy metal components such as vanadium in the caking filler remain in the coke.

  When the coke is used in the blast furnace, most of the sulfur component and vanadium and other heavy metal components remaining in the coke are transferred to the slag generated in the blast furnace, and are removed and separated from the hot metal.

  According to the inventor's study, when producing coke using a heavy petroleum-based fraction as a caking filler, the blending ratio of caking filler to raw coal is 5% or less. It was confirmed that coke having a good quality that does not affect the quality of the hot metal in the blast furnace due to the residue of heavy metal components such as sulfur components and vanadium can be produced.

  As the blending ratio of the caking filler to the raw coal is reduced, the residue of heavy metal components such as sulfur and vanadium in the coke is reduced.From this point, the blending ratio of the caking filler to the raw coal is: Preferably it is 2% or less.

  Also, the sulfur component concentration in the coke oven gas is increased by shifting the sulfur component in the caking filler into the pyrolysis gas during coke production. It was also confirmed that the existing coke oven gas purification equipment associated with the process could be sufficiently desulfurized during normal operation.

If the blending amount of the non-slightly caking coal exceeds 20% by mass and the SDA pitch exceeds 5%, the coke strength (DI ¹⁵⁰ ₁₅ ) will be lower than 84.5. Since the coke strength is not extremely deteriorated, if the coke strength level required by the blast furnace is lower than 84.5, it may be usable even in a range exceeding 5%.

  The present invention is particularly effective when the blending amount of the non-slightly caking coal exceeds 20% by mass. Furthermore, the expansion rate of the raw coal after the blending of the non-slightly caking coal (weighted average of the expansion rate) Is 30 to 100%, and / or if the volatile content of the raw coal is 22.5 to 32.5 dry%, the coke strength is remarkably enhanced in combination with the effect of the caking filler. can do.

  Thus, the reason why 30 to 100% is preferable as the range of the expansion rate (weighted average of expansion rate) of the raw coal is as follows.

  When the expansion rate of the raw coal is less than 30%, the coal particles are not sufficiently bonded to each other, and the effect of pore expansion and rounding of the pores due to the addition of the caking filler is only in a part of the adhesion region. This is because it does not act effectively and the dispersion of the caking filler addition effect becomes extremely large, and as a result, the caking filler addition effect becomes relatively small.

  Also, when the expansion rate of the raw coal exceeds 100%, the DI level is already high, the pore size is close to the appropriate size, and the pore shape is rounded, so the addition of caking filler This is because the effects of the pore expanding action and the pore rounding action become relatively small.

  The reason why 22.5 to 32.5 dry% is preferable as the range of the volatile content of the raw coal is as follows. When the volatile matter content of the raw coal is less than 22.5%, the coke yield is large and the wall thickness is thick, and the coke wall is thickened with pores due to the caking filler, and the pores are rounded. This is because the effect of the caking filler is relatively reduced.

  When the volatile content of the raw coal exceeds 32.5%, because the coke yield is small, the wall thickness is thin, the effect of the caking filler in the scope of the present invention with a small wall thickness increasing effect, This is because it becomes relatively small.

  In addition, in the case of blended coal with a blending ratio of non-slightly caking coal of less than 20%, high strength coke can be produced without adding the caking filler, but even in this case, the caking filler of the present invention can be produced. It is possible to obtain the effect of increasing the coke strength.

  Next, examples of the present invention will be described. The conditions of the examples are one example of conditions adopted for confirming the feasibility and effects of the present invention, and the present invention is limited to this one example of conditions. Is not to be done. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

(Example)
A caking filler (SDA pitch) having the composition shown in Table 1 was prepared. The caking fillers of symbols V, A, B, and C are within the composition range defined in the present invention, and the caking fillers of symbols N1, K1, and K2 are outside the above composition range. (See FIG. 1).

  SDA pitch V was obtained by extracting light oil from atmospheric residue using pentane as an extraction solvent, a flow rate ratio of pentane and atmospheric residue to 6 and an extraction rate of 85%. SDA pitch A was obtained by extracting light oil from atmospheric residue using butane as an extraction solvent, a flow rate ratio of butane and atmospheric residue to 6 and an extraction rate of 75%.

  SDA pitch B was obtained by extracting light oil from atmospheric residual oil using butane as an extraction solvent, with a flow ratio of butane and atmospheric residual oil of 6 and an extraction rate of 80%. SDA pitch C was obtained by extracting light oil from atmospheric residual oil using propane as an extraction solvent with a flow rate ratio of propane and atmospheric residual oil of 10 and an extraction rate of 65%.

  N1 was obtained by extracting light oil from atmospheric residual oil using atmospheric residual oil as a raw material, using propane as an extraction solvent, setting the flow rate ratio between propane and atmospheric residual oil to 5 and setting the extraction rate to 40%. . K1 and K2 are obtained by mixing fractions obtained by distillation of coal tar.

  The extraction rate was defined as the recovery rate of light oil relative to petroleum heavy oil, and the extraction temperature was appropriately selected so as to achieve this extraction rate.

Coke was produced by adding the caking filler of the composition shown in Table 1 to the raw coal blended with 40% non-slightly caking coal in the addition amount shown in Table 2 and dry distillation. Then, DI ¹⁵⁰ ₁₅ of the produced coke was measured. The results are also shown in Table 2. Table 2 shows the measurement results of the S content (% by mass) and the V content (ppm) in the caking filler and coke. In addition, S content in the said raw coal was 0.5 (mass%), and V content was 20 (ppm).

From Table 2, it can be seen that in the comparative example, DI ¹⁵⁰ ₁₅ is 84 or less, but in Examples 1 to 6, strength of DI ¹⁵⁰ ₁₅ : 85 level is obtained. In addition, the contents of S and V in the cokes of Invention Examples 1 to 6 using SDA pitches A to C and V produced from petroleum heavy oil as caking fillers were acceptable for blast furnace coke. It was.

  On the other hand, SDA pitch V produced from petroleum-based heavy oil was used as a caking filler, and the S in the coke of Comparative Example 4 was added in an amount exceeding 10% as specified in the present invention. And the content of V became high compared with the invention example.

As described above, according to the present invention, a high strength coke of 84.5 or more is produced with DI ¹⁵⁰ ₁₅ by blending SDA pitch having a TI component of 1% or less into the raw coal as a caking filler. Can do.

  Therefore, the present invention effectively utilizes the SDA pitch of petroleum residue generated in large quantities to produce high-strength coke for blast furnaces, so that it can be used not only for the steel industry but also for environmental protection. Is high.

It is a figure which shows the composition area | region (area | region enclosed with the continuous line) of SDA pitch used by this invention. SDA pitch (HS ingredients: 31.3% TI ingredient: 0.3%, and, HITS component and inevitable residual component: balance) is a diagram showing the relationship of the amount and coke strength (DI ^0.99 _15).

Claims (13)

  A caking filler to be blended with raw coal to produce high-strength coke, a component soluble in hexane (HS component): more than 20% and 90% or less, and a component insoluble in toluene (TI component): A caking filler excellent in strength-enhancing properties, comprising 1% or less, and the balance comprising a component insoluble in hexane and soluble in toluene (HITS component) and an unavoidable residual component.   The caking filler excellent in strength enhancement characteristics according to claim 1, wherein the raw coal contains more than 20% by mass of non-slightly caking coal.   The caking filler having excellent strength enhancement characteristics according to claim 1 or 2, wherein the caking filler is a petroleum solvent degreasing pitch.   The caking filler having excellent strength enhancement characteristics according to any one of claims 1 to 3, wherein the raw coal has a total expansion rate (weighted average of total expansion rates) of 30 to 100%. .   The caking filler having excellent strength enhancement characteristics according to any one of claims 1 to 4, wherein a volatile content of the raw coal is 22.5 to 32.5 dry%.   In the method for producing high-strength coke by dry distillation of raw coal, components soluble in hexane (HS component): more than 20% and 90% or less, and components insoluble in toluene (TI component): 1 A method for producing high-strength coke, characterized in that it contains a caking filler consisting of a component (HITS component) insoluble in hexane and the remainder soluble in toluene (HITS component) and an unavoidable residual component.   The method for producing high-strength coke according to claim 6, wherein the raw coal contains more than 20 mass% of non-slightly caking coal.   The method for producing high-strength coke according to claim 6 or 7, wherein a total expansion rate of the raw coal (a weighted average of the total expansion rates) is 30 to 100%.   The method for producing high-strength coke according to any one of claims 6 to 8, wherein a volatile content of the raw coal is 22.5 to 32.5 dry%.   The method for producing high-strength coke according to any one of claims 6 to 9, wherein the caking filler is blended in an amount of 5% by mass or less based on raw coal.   The method for producing high-strength coke according to any one of claims 6 to 9, wherein the caking filler is blended in an amount of 2% by mass or less based on raw coal.   The method for producing high-strength coke according to any one of claims 6 to 9, wherein the caking filler is blended in an amount of 0.2 to 0.8 mass% with respect to the raw coal.   The method for producing high-strength coke according to any one of claims 6 to 12, wherein the caking filler is a petroleum solvent degreasing pitch.

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