JP2017173294A - Method for estimating strength of coke and method for manufacturing coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for more accurately estimating a drum strength DI.SOLUTION: The method for estimating the strength of coke obtained by carbonizing a mixed coal obtained by mixing two or more kinds of single coals with a caking additive comprises: the step A of obtaining the indexes Iand indexes Iof each single coal to be mixed and caking additive; the step B of requiring a difference dHIo between the index Iand index Iof the mixed coal before mixing the caking additive on the basis of the indexes I, the indexes Iand the mixing ratio of each single coal; and the step C of estimating the drum strength DI of the mixed coal after mixing the caking additive on the basis of the index dHIo of the mixed coal before mixing the caking additive, an index dHIbeing a difference between the index Iand index Iof the caking additive and the mixing ratio of the caking additive.SELECTED DRAWING: None

Description

  The present invention relates to a coke strength estimation method and a coke production method.

  Conventionally, coke used as an iron-making raw material is obtained by dry distillation of blended coal obtained by blending plural types of simple coal. Coke is required to have high strength in order to ensure liquid permeability in a blast furnace.

  In general, in order to obtain high-strength coke, it is necessary to add a lot of strongly caking coal. However, in recent years, with the rise of emerging countries, there is concern about the depletion of strong caking coal. Therefore, in order to expand the raw material range for coke, studies are being made to maintain high strength while blending a large amount of low-grade coal.

For example, in Patent Document 1, as a method for estimating the coke drum strength, the hydrogen to carbon atom ratio H / C of the active component of the raw coal and the oxygen to carbon atom ratio O / C of the component are determined by a specific method. A method for estimating the drum strength DI of coke using the corrected index I _{H / C} and index I _{O / C} is disclosed (particularly, refer to paragraphs [0021] to [0027] of Patent Document 1).

JP-A-4-275389

  It is desirable that the method of estimating the coke drum strength DI is more accurate. Therefore, an object of the present invention is to provide a more accurate estimation method of the drum strength DI. Moreover, an object of this invention is to provide the manufacturing method of the coke using the said estimation method.

The present inventors diligently studied a method for estimating the drum strength DI of coke. In particular, intensive studies were conducted on the relationship between the blended coal (charging coal) properties obtained in the low-grade coal multiple blending test and the coke strength. As a result, it has been found that the coke strength improving effect (α) has a high correlation with the index dHI ₀ before blending the binder. The index dHI ₀ before the binder is mixed is an index I _{H / C} of the blended charcoal before the binder is blended when blending a plurality of types of plain coal and the binder. An index obtained by correcting the hydrogen / carbon atom ratio of the coal blend before blending with a specific method) and an index I _{O / C} (the oxygen / carbon atom ratio of the coal blend before blending with a specific method) It is the difference from the corrected index. Then, if the drum strength DI is estimated using the index dHI ₀ , the index dHI _a that is the difference between the index I _{H / C} and the index I _{O / C} of the binder, and the mixture ratio of the binder. The present inventors have found that more accurate estimation can be performed and have completed the present invention.

That is, the coke strength estimation method according to the present invention is:
A method for estimating the strength of coke obtained by dry distillation of blended coal obtained by blending plural kinds of simple coal and caking additive,
Step A for obtaining the index I _{H / C} and the index I _{O / C} of each simple coal to be blended and the binder according to the following procedures (a) to (b),
Procedure (a): The value calculated by the following formula (1) using the heating loss when heating the simple coal and the caking additive is taken as the index I _{H / C.}
I _{H / C} = aX ₀ + b (1)
(However, X ₀ = Loss on heating (mg / g-coal.daf), and a and b are constants)
Procedure (b): The value calculated by the following equation (2) using the generated amounts of CH ₄ , CO, and CO ₂ in the gas generated during the procedure (a) is taken as an index I 2 _{O / C.}
I _{O / C} = cX ₁ + d (2)
(However, X ₁ = 1− [CH ₄ / (CH ₄ + CO + CO ₂ )], and c and d are constants)
And metrics I _{H / C} and the index I _{O / C} of each of the plain carbon obtained by the step A, based on the proportions of the said Tan'ajisumi, indication of coal blend before caking formulation I _H Step B for obtaining the difference dHI ₀ between _{/ C} and the index I 2 _{O / C} , and
The index dHI _{0 of the} coal before blending the binder obtained in step B, the index dHI _a which is the difference between the index I _{H / C} and the index _{IO / C} of the binder, and the binder Step C of estimating the drum strength DI of the blended coal after the binder is blended based on the blending ratio
It is characterized by including.

According to the above construction, an indicator DHI ₀ of coal blend before caking formulation, the index DHI _a caking material, based on the mixing ratio of caking, drum coal blend after caking formulation Since the intensity DI is estimated, the value of the drum intensity DI can be estimated with high accuracy. This point is clear from the examples.
Further, based on the index dHI _{0 of the} coal blend before blending the binder, the index dHI _a of the binder, and the blending ratio of the binder, the drum strength DI of the blended coal after blending is determined. For estimation, the drum strength DI can be calculated (estimated) at various blending ratios, and the blending ratio can be selected by trial and error. In particular, it is possible to easily select a blending ratio in which the blending amount of low-grade coal is increased while keeping the drum strength DI at a certain level or more.

Moreover, the method for producing coke according to the present invention includes:
Using the coke strength estimation method, the step D of determining the blending ratio of the simple coal and the caking additive that the estimated value of the coke strength becomes a certain value or more, and
Step E of blending simple coal and caking additive at the blending ratio determined in Step D
It is characterized by including.

  According to the above configuration, since the coke strength estimation method is used, it is possible to easily select a blending ratio in which the blending amount of the low-grade coal is increased while maintaining the drum strength DI at a certain level or more. As a result, if simple coal and caking additive are blended at a selected blending ratio, it is possible to produce a coke having a drum strength DI of a certain level and an increased blending amount of low-grade coal. Become.

In the above configuration, as the binder, the index dHIa is 0.80 or more, the ash content is 0.2 to 9.0%, the volatile content is 30 to 55%, and the volume ratio TI of the total amount of the inert tissue is 0 to 0. It is preferable to use 0 to 10% of a caking additive that becomes 40%.
The inventors of the present invention have found that the coke strength tends to increase as the index dHIa of the binder is larger than the smaller. Therefore, when the one having the above-described configuration is adopted as the binder, it is possible to produce coke in which the blending amount of low-grade coal is increased while maintaining the drum strength DI at a certain level or more.

In the arrangement, the step B is obtained DHI ₀ is such that -0.60～-0.05, preferably includes the step of determining the proportions of the said Tan'ajisumi. When dHI ₀ is −0.60 to −0.05, it is possible to produce coke in which the blending amount of low-grade coal is further increased while maintaining the drum strength DI at a certain level or more.

  According to the present invention, it is possible to provide a coke strength estimation method capable of estimating the value of the drum strength DI with high accuracy. In addition, it is possible to provide a method for producing coke in which coke in which the blending amount of low-grade coal is increased while maintaining coke strength at a certain level or more can be provided.

  Hereinafter, embodiments of the present invention will be described.

The coke strength estimation method according to the present embodiment is:
A method for estimating the strength of coke obtained by dry distillation of blended coal obtained by blending plural kinds of simple coal and caking additive,
Step A for obtaining the index I _{H / C} and the index I _{O / C} of each simple coal to be blended and the binder according to the following procedures (a) to (b),
Procedure (a): The value calculated by the following formula (1) using the heating loss when heating the simple coal and the caking additive is taken as the index I _{H / C.}
I _{H / C} = aX ₀ + b (1)
(However, X ₀ = Loss on heating (mg / g-coal.daf), and a and b are constants)
Procedure (b): The value calculated by the following equation (2) using the generated amounts of CH ₄ , CO, and CO ₂ in the gas generated during the procedure (a) is taken as an index I 2 _{O / C.}
I _{O / C} = cX ₁ + d (2)
(However, X ₁ = 1− [CH ₄ / (CH ₄ + CO + CO ₂ )], and c and d are constants)
And metrics I _{H / C} and the index I _{O / C} of each of the plain carbon obtained by the step A, based on the proportions of the said Tan'ajisumi, indication of coal blend before caking formulation I _H Step B for obtaining the difference dHI ₀ between _{/ C} and the index I 2 _{O / C} , and
The index dHI ₀ of the blended coal before blending the binder obtained in step B, the index dHI _a which is the difference between the index I _{H / C} and the index _{IO / C} of the binder, and the binder Step C of estimating the drum strength DI of the blended coal after the binder is blended based on the blending ratio
including.

  Hereinafter, each step will be described.

[Step A]
First, in the process A, the index I _{H / C} and the index I _{O / C} of each simple coal to be blended and the binder are obtained by the following procedures (a) to (b).
Procedure (a): The value calculated by the following formula (1) using the heating loss when heating the simple coal and the caking additive is taken as the index I _{H / C.}
I _{H / C} = aX ₀ + b (1)
(However, X ₀ = Loss on heating (mg / g-coal.daf), and a and b are constants)
Procedure (b): The value calculated by the following equation (2) using the generated amounts of CH ₄ , CO, and CO ₂ in the gas generated during the procedure (a) is taken as an index I 2 _{O / C.}
I _{O / C} = cX ₁ + d (2)
(However, X ₁ = 1− [CH ₄ / (CH ₄ + CO + CO ₂ )], and c and d are constants)

The index I _{H / C} and the index I _{O / C} are indices that can be used to estimate the drum strength DI of the blended coal. The details are described in JP-A-4-275389 (particularly, paragraphs [0019] to [0027]), and detailed description thereof is omitted here. In addition to the use of fine or non-caking coal that has low caking properties or no caking properties, the drum strength DI of the blended coal can be estimated with the same accuracy as when only caking coal is used. It is an indicator that can.

Further, the value calculated by the above formula (1) using the heating loss can be used as the index I _{H / C,} and CH ₄ , CO, CO ₂ in the gas generated during the procedure (a). As for the point that the value calculated by the above formula (2) can be used as the index _{IO / C} by using the generation amount of NO, details are disclosed in JP-A-4-275389 (particularly, paragraph [0039]). Although detailed description is omitted here, the inventors of the present applicant have previously found that there is a high degree of correlation between I _{H / C} and heat loss of raw coal. And that there is a high degree of correlation between I 2 _{O / C} and the CH ₄ ratio in the gas generated from the raw coal. Simultaneous measurement is relatively easy with the combined device. I have found it. Based on this, the present invention decided to obtain the values of the index I _{H / C} and the index I _{O / C} of each simple coal and caking additive.

  The constants a to d are constants determined by the measurement method, and can be obtained by statistically analyzing a large number of measurement data.

[Step B]
Based on the index I _{H / C} and index I _{O / C of} each simple charcoal and the binder obtained in step A, and the blending ratio of each simple charcoal, the compounding before the binder compounding The difference dHI ₀ between the charcoal index I _{H / C} and the index I _{O / C} is determined.

In this step, based on the index I _{H / C} and the index I _{O / C} of each simple coal, the blending ratio is weighted and averaged to determine the index dHI ₀ of the blended coal before the binder is blended. The dHI ₀ of the coal blend before blending the binder means the dHI of the coal blend when the binder is not blended.

Step B, DHI ₀ obtained is such that -0.60～-0.05, preferably includes the step of determining the proportions of the said Tan'ajisumi. In this step, for example, the calculation is repeated while changing the blending ratio until the dHI ₀ calculation result becomes −0.60 to −0.05 due to trial and error. When the calculation result of dHI ₀ becomes −0.60 to −0.05, the process proceeds to Step C. When dHI ₀ is −0.60 to −0.05, it is possible to produce coke in which the blending amount of low-grade coal is further increased while maintaining the drum strength DI at a certain level or more.

[Step C]
The index dHI ₀ of the blended coal before blending the binder obtained in step B, the index dHI _a which is the difference between the index I _{H / C} and the index _{IO / C} of the binder, and the binder Based on the blending ratio, the drum strength DI of the blended coal after blending the binder is estimated.

Specifically, the drum strength DI of the blended coal after the binder is blended is estimated by the following estimation formula.
[Estimated drum strength DI] = f (dHI ₀ ) + α × dHIa × X
dHI ₀ : Index dHI ₀ of blended coal before caking additive blending
f (dHI ₀ ): Estimated value of drum strength of blended coal before blending binder (determined from dHI ₀ of blended coal before blending of binder under constant firing conditions)
α: DI improvement effect per binder dHIa = 1 determined by firing conditions
α = k × dHI ₀ + h (k and h are constants determined by firing conditions, and are determined by analyzing measurement data by a statistical method.)
dHIa: The difference between the index I _{H / C} and the index I _{O / C} of the binder X: The compounding ratio of the binder (outer frame weight%)

As a result of intensive studies on the relationship between the blended coal properties obtained in the past and the low-grade coal multiple blending test and the coke strength, the above-described estimation formula, the coke strength improvement effect (α), This is an equation obtained based on the finding that there is a high degree of correlation with the index dHI ₀ before the binder compounding.
If this estimation formula is used, it is possible to estimate the drum strength DI of the blended coal after the binder is blended with high accuracy. This point has been confirmed in examples described later.

  The coke strength estimation method according to the present embodiment has been described above.

  Next, the manufacturing method of the coke which concerns on this embodiment is demonstrated.

The method for producing coke according to the present embodiment is as follows:
Using the coke strength estimation method, the step D of determining the blending ratio of the simple coal and the binder, where the estimated value of the drum strength DI of the blended coal after the binder is mixed, and
Step E of blending simple coal and caking additive at the blending ratio determined in Step D
including.

  Hereinafter, each step will be described.

[Step D]
First, in the process D, the blending ratio of simple charcoal and caking additive that makes the estimated value of the drum strength DI of the blended charcoal after blending the caulking material equal to or greater than a certain value is determined using the coke strength estimation method.

  In this step, the drum strength DI is calculated (estimated) at various blending ratios using the coke strength estimation method, and the blending ratio at which the estimated value of the drum strength DI becomes a certain value or more is determined by trial and error. Can be determined. In particular, a blending ratio in which the blending amount of the low-grade coal is increased as much as possible while the drum strength DI is kept above a certain level is selected.

[Step E]
Next, simple charcoal and caking additive are blended at the blending ratio determined in Step D.

  The coke strength estimation method is a method capable of estimating the drum strength DI of the coal blend after blending the binder with high accuracy. Therefore, by co-distilling the blended coal blended at the blending ratio determined in the step D, it is possible to produce a coke having a drum strength DI of a certain level or more and an increased blend amount of low-grade coal. It becomes possible.

As the binder, the index dHIa is 0.80 or more, the ash content is 0.2 to 9.0%, the volatile content is 30 to 55%, and the volume ratio TI of the total amount of inert tissue is 0 to 40%. It is preferable to use 0 to 10% of the binder.
When the binder having the above-described configuration is used as the binder, it is possible to produce coke in which the blending amount of low-grade coal is increased while maintaining the drum strength DI at a certain level or more.

  The coke manufacturing method according to the present embodiment has been described above.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
<Verification of correlation between measured value and estimated value of coke strength DI>
First, seven types of plain charcoal (A charcoal to G charcoal) shown in Table 1 and one type of caking additive (caking agent 1) were prepared. In addition, A coal-D charcoal are caking coal (strong caking coal or quasi-strong caking coal), and E charcoal-G charcoal are low grade coal.
Table 1 also shows the properties of these simple charcoal and caking additive (ash, volatile matter, log MF, TI, I _{H / C} , I _{O / C} , dHI). dHI is a value obtained by subtracting I _{O / C} from I _{H / C} , that is, dHI = [I _{H / C} −I _{O / C} ]. In Table 1, ash, volatile matter, logMF, and TI mean the following.
The heating loss necessary for obtaining the index I _{H / C} and the index I _{O / C} , and the amount of CH ₄ , CO, and CO ₂ generated are the Rigaku apparatus name: differential thermobalance-mass spectrometry. A value obtained by heating to 1000 ° C. using a simultaneous measuring apparatus ThermoMass (TG-MS) was used.
Ash content: Mass percentage of the total amount of ash remaining after heat-ashing coal in air (as defined in JIS M8812)
Volatile matter: Mass percentage of the total weight of coal when the coal is heated (as defined in JIS M8812)
log MF: Maximum Gieseller fluidity (logarithmic value of the value at which the rotor blades show the maximum number of revolutions in a test using a Giesera-Plastometer (coal heat softening and melting characteristics test stipulated in JIS M8801). An index representative of the caking property of
TI: Volume ratio of the total amount of inert tissue to the whole coal (measured according to JIS M 8816)

(Production Example 1)
A charcoal to D charcoal and G charcoal were blended at a predetermined ratio. When blending, the mixture was pulverized with a jaw crusher or a coffee mill so that the proportion of particles having a pulverized particle size of 3 mm or less was about 80%. In addition, all the manufacture examples 1-20 are mix | blended so that the mixture ratios of charcoal may differ.

(Production Example 2)
A charcoal-D charcoal, G charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The blending ratio of the binder 1 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal, G charcoal). When the caking additive was blended, it was blended after being ground with a jaw crusher or a coffee mill so that the proportion of particles having a pulverized particle size of 3 mm or less was about 100%. This also applies to the following production examples when a caking additive is blended.
Here, the “binding material addition rate” refers to the weight ratio of the binding material to charcoal other than the binding material. For example, in Production Example 2, the weight ratio of the binder to 5.3 parts by weight of charcoal other than the binder is 5.3 parts by weight. Therefore, the binder addition rate in Production Example 2 is 5. 3%.
[5.3 / 100] × 100 (%) = 5.3 (%)

(Production Example 3)
A charcoal-D charcoal, G charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The blending ratio of the binder 1 was 11.1 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal, G charcoal).

(Production Example 4)
A charcoal to D charcoal and G charcoal were blended at a predetermined ratio.

(Production Example 5)
A charcoal-D charcoal, G charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The blending ratio of the binder 1 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal, G charcoal).

(Production Example 6)
A charcoal-D charcoal, G charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The blending ratio of the binder 1 was 11.1 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal, G charcoal).

(Production Example 7)
A charcoal to E charcoal were blended at a predetermined ratio.

(Production Example 8)
A charcoal-E charcoal and caking additive 1 were mix | blended in the predetermined ratio. The compounding ratio of the binder 1 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to E charcoal).

(Production Example 9)
A charcoal to E charcoal were blended at a predetermined ratio.

(Production Example 10)
A charcoal-E charcoal and caking additive 1 were mix | blended in the predetermined ratio. The compounding ratio of the binder 1 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to E charcoal).

(Production Example 11)
A charcoal to D charcoal and F charcoal were blended at a predetermined ratio.

(Production Example 12)
A charcoal-D charcoal, F charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The compounding ratio of the binder 1 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal and F charcoal).

(Production Example 13)
A charcoal-D charcoal, F charcoal, and the caking additive 1 were mix | blended in the predetermined ratio. The blending ratio of the binder 1 was 11.1 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder (A charcoal to D charcoal and F charcoal).

Table 2 shows the properties (ash content, volatile content, log MF, TI, I _{H / C} , I _{O / C} , dHI ₀ ) of the blended coals of Production Examples 1 to 13 before blending.
Among the properties of the blended charcoal before the binder is blended, ash, volatile matter, logMF, TI, I _{H / C} , and I _{O / C} are weighted by blending proportions of the charcoal properties (see Table 1). The average value is obtained (the property of the binder is not included in the weighted average). For example, I _{H / C} of the blended coal of Production Example 1 is a value obtained by weighted averaging of each of the I _{H / Cs} of coal A to coal D and coal G with a blending ratio. The _{IO / C} of the blended coal of Production Example 1 is a value obtained by weighted averaging the respective _{IO / C} of coals A to D and G coal with the blending ratio.
Further, for example, I _{H / C} of the blended coal of Production Example 2 is a value obtained by weighted average of each I _{H / C} of coal A to coal D and coal G (weighted average). (IH _{/ C} of the binder 1 is not included). I _{O / C} of coal blend in Production Example 3, A charcoal to D, and a value obtained by weighted average proportion of each I _{O / C} of G charcoal (caking when weighted average 1 _{IO / C} is not included).
dHI ₀ is a value obtained by subtracting _{IO / C} of the blended coal from IH _{/ C} of the blended coal.

  After preparing the blended charcoal, the water content was adjusted to 7.5% ± 0.2%.

Next, the moisture-adjusted sample was filled in a retort of L: 380 mm × T: 400 mm × H: 350 mm at a packing density of 750 kg-dry / m ³ .

  Next, coke was obtained by carbonization at a carbonization temperature of 1,100 ° C. for about 19 hours.

<Drum strength test>
The obtained coke was subjected to a shutter test (head drop of 2 m) twice, and then DI ¹⁵⁰ ₁₅ was measured by a coke strength evaluation method (150 rotations with a drum tester) defined in JIS K 2151. The results are shown in the column “Measured Value” in Table 2.

<Calculation of the estimated value of drum strength using the index dHI ₀ of the coal blend before blending the binder>
The drum strength DI of the coal blend after blending the binder was estimated by the following formula.
[Estimated drum strength DI] = f (dHI ₀ ) + α × dHIa × X
dHI ₀ : Index dHI ₀ of blended coal before caking additive blending
f (dHI ₀ ): Estimated value of drum strength of blended coal before binding material blending α: DI improvement effect per binding material dHIa = 1 determined by firing conditions
α = k × dHI ₀ + h (k and h are constants determined by firing conditions)
dHIa: The difference between the index I _{H / C} and the index I _{O / C} of the binder X: The compounding ratio of the binder (outer frame weight%)

Here, under the same firing conditions as in Production Examples 1 to 13, from past experimental results carried out by changing the blending ratio of simple coal and caking additive, in Example 1 (Production Example 1-13) f (dHI ₀ ) and α are as follows.
f (dHI ₀ ) = − 18.757 × (dHI ₀ ) × (dHI ₀ ) + 1.6271 × (dHI ₀ ) +85.163
α = −1.199 × (dHI ₀ ) −0.041 (when the binder content is 5.3% or less)
α = −0.924 × (dHI ₀ ) −0.064 (when the binder content is greater than 5.3%)

  Based on the above, the estimated drum strength DI of Production Example 2, Production Example 3, Production Example 5, Production Example 6, Production Example 8, Production Example 10, Production Example 12, and Production Example 13 was calculated. The results are shown in the “estimated value” column of Table 2.

  As can be seen from the comparison between the “measured value” and the “estimated value” in Table 2, the estimated value of any manufacturing example according to Example 1 was close to the actually measured value.

(Example 2)
<Verification of correlation between measured value and estimated value of coke strength DI>
First, nine types of plain coal (H charcoal to P charcoal) shown in Table 3 and three types of caking materials (caking material 2 to caking material 4) were prepared. In addition, H charcoal-M charcoal are caking coal (strong caking coal or semi-strong caking coal), and N charcoal-P charcoal are low grade coal.
Table 3 also shows the properties of these simple charcoal and caking additive (ash, volatile matter, log MF, TI, I _{H / C} , I _{O / C} , dHI). The meaning of each property is the same as in Example 1.

(Production Example 14)
H charcoal to P charcoal were blended at a predetermined ratio.

(Production Example 15)
H charcoal to P charcoal and caking additive 2 were blended at a predetermined ratio. The blending ratio of the binder 2 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder.

(Production Example 16)
H charcoal to P charcoal and caking additive 3 were blended at a predetermined ratio. The blending ratio of the binder 3 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder.

(Production Example 17)
H charcoal to P charcoal were blended at a predetermined ratio.

(Production Example 18)
H charcoal to P charcoal and caking additive 2 were blended at a predetermined ratio. The blending ratio of the binder 2 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder.

(Production Example 19)
H charcoal to P charcoal and caking additive 3 were blended at a predetermined ratio. The blending ratio of the binder 3 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder.

(Production Example 20)
H charcoal to P charcoal and caking additive 4 were blended at a predetermined ratio. The blending ratio of the binder 4 was 5.3 parts by weight with respect to a total of 100 parts by weight of charcoal other than the binder.

  Thereafter, the blended coals of Production Examples 14 to 20 were dry-distilled in the same manner as in Example 1 except that the retort was charged at a packing density of 0.735 kg-dry / liter to obtain coke.

Table 4 shows the properties (ash content, volatile content, log MF, TI, I _{H / C} , I _{O / C} , dHI ₀ ) of the coal blends of Production Example 14 to Production Example 20. The meaning of each property is the same as in Example 1.

<Drum strength test>
For the obtained coke, DI ¹⁵⁰ ₁₅ was measured in the same manner as in Example 1. The results are shown in the “Measured value” column of Table 4.

<Calculation of the estimated value of drum strength using the index dHI ₀ of the coal blend before blending the binder>
The drum strength DI of the coal blend after blending the binder was estimated by the following formula, as in Example 1.
[Estimated drum strength DI] = f (dHI ₀ ) + α × dHIa × X
dHI ₀ : Index dHI ₀ of blended coal before caking additive blending
f (dHI ₀ ): Estimated value of drum strength of blended coal before binding material blending α: DI improvement effect per binding material dHI = 1 determined by firing conditions
α = k × dHI ₀ + h (k and h are constants determined by firing conditions)
dHIa: The difference between the index I _{H / C} and the index I _{O / C} of the binder X: The compounding ratio of the binder (outer frame weight%)

Here, from the past experimental results carried out under the same firing conditions as in Production Examples 14 to 20 and changing the blending ratio of simple coal and caking additive, in Example 2 (Production Examples 14-20). f (dHI ₀ ) and α are as follows.
f (dHI ₀ ) = − 107.7 × (dHI ₀ ) × (dHI ₀ ) + 7.96893 × (dHI ₀ ) +84.805
α = −1.199 × (dHI ₀ ) −0.041 (when the binder content is 5.3% or less)
α = −0.924 × (dHI ₀ ) −0.064 (when the binder content is greater than 5.3%)

  Based on the above, the estimated drum strength DI of Production Example 15, Production Example 16, Production Example 18, Production Example 19, and Production Example 20 was calculated. The results are shown in the “estimated value” column of Table 4.

  As can be seen from the comparison between the “measured value” and the “estimated value” in Table 4, the estimated value of any manufacturing example according to Example 2 was close to the actually measured value.

  As described above, as can be seen from the first and second embodiments, according to this estimation method, the drum strength can be estimated with high accuracy.

Claims (4)

A method for estimating the strength of coke obtained by dry distillation of blended coal obtained by blending plural kinds of simple coal and caking additive,
Step A for obtaining the index I _{H / C} and the index I _{O / C} of each simple coal to be blended and the binder according to the following procedures (a) to (b),
Procedure (a): The value calculated by the following formula (1) using the heating loss when heating the simple coal and the caking additive is taken as the index I _{H / C.}
I _{H / C} = aX ₀ + b (1)
(However, X ₀ = Loss on heating (mg / g-coal.daf), and a and b are constants)
Procedure (b): The value calculated by the following equation (2) using the generated amounts of CH ₄ , CO, and CO ₂ in the gas generated during the procedure (a) is taken as an index I 2 _{O / C.}
I _{O / C} = cX ₁ + d (2)
(However, X ₁ = 1− [CH ₄ / (CH ₄ + CO + CO ₂ )], and c and d are constants)
And metrics I _{H / C} and the index I _{O / C} of each of the plain carbon obtained by the step A, based on the proportions of the said Tan'ajisumi, indication of coal blend before caking formulation I _H Step B for obtaining the difference dHIo between _{/ C} and the index _{IO / C} , and
And metrics dHIo of coal blend before the caking formulation obtained by the step B, the index DHI _a is the difference between the index I _{H / C} and the index I _{O / C} of caking, the formulation of caking Step C for estimating the drum strength DI of the blended coal after the binder is blended based on the ratio
A coke strength estimation method comprising: Using the method for estimating the strength of coke according to claim 1, step D for determining the blending ratio of simple charcoal and caking additive that makes the estimated value of coke strength equal to or greater than a certain value, and
Step E of blending simple coal and caking additive at the blending ratio determined in Step D
A method for producing coke, comprising:   As the binder, the index dHIa is 0.80 or more, the ash content is 0.2 to 9.0%, the volatile content is 30 to 55%, and the volume ratio TI of the total amount of inert tissue is 0 to 40%. The method for producing coke according to claim 2, wherein 0 to 10% of a caking additive is used. Wherein step B, DHI ₀ obtained is such that -0.60～-0.05, production of coke as claimed in claim 2 or 3 including the step of determining the proportions of the said Tan'ajisumi Method.