JP2022158407A - Method for predicting csr of blast furnace coke, method for predicting cri of blast furnace coke, and method for manufacturing blast furnace coke - Google Patents

Abstract

To achieve both enlarging coke particle diameters and CSR or the like by adding a low-shrinkage carbonaceous material.SOLUTION: In a method for predicting a CSR of a blast furnace coke manufactured by dry-distilling a blended coal to which a low-shrinkage carbonaceous material is added, an influential degree Ci (CSR) on CSR of a coke of a low-shrinkage carbonaceous material to be added to the blended coal is calculated for each predetermined particle size class of the low-shrinkage carbonaceous material. A CSR of the blast furnace coke is predicted on the basis of the calculated influential degree Ci (CSR) for each particle size class. In a method for predicting a CRI of a blast furnace coke manufactured by dry-distilling a blended coal to which a low-shrinkage carbonaceous material is added, an influential degree Ci (CRI) on CRI of a coke of a low-shrinkage carbonaceous material to be added to the blended coal is calculated for each predetermined particle size class of the low-shrinkage carbonaceous material. A CRI of the blast furnace coke is predicted on the basis of the calculated influential degree Ci (CRI) for each particle size class.SELECTED DRAWING: None

Description

The present invention relates to a method for predicting the CSR and CRI of blast furnace coke produced by carbonizing blended coal to which low-shrinkage carbonaceous materials are added, and a method for producing blast furnace coke using these prediction methods.

Blast furnace coke has a role as a filler for ensuring air permeability in the furnace. Therefore, as a quality control index for blast furnace coke, it is required to increase the coke particle size while maintaining the coke strength (DI). As a method for enlarging the coke particle size, a method of adding a low-shrinkage carbonaceous material such as coke fines to blended coal is known. Low-shrinkage carbon material does not expand when coal softens and melts, and does not shrink easily when coal re-solidifies. , lowers the DI.

Patent Document 1 discloses a method in which the degree of influence of the brand and length of low-shrinkage carbonaceous material on coke particle size and DI is determined in advance, and blending adjustment is performed so as to satisfy the target coke particle size and DI. Proposed.

Here, blast furnace coke is required to have a high hot reaction strength (CSR) in addition to a high DI. This is because if the CSR is low, the amount of coke pulverized after the reaction in the furnace increases, impairing the air permeability of the blast furnace. In addition, the coke reactivity index (CRI) is also required to be low. Higher CRI results in higher reactivity in the furnace and increased coke grind as in the case of CSR.

Patent Document 2 proposes a method of predicting CSR from operating conditions including CRI of single coal coke, ultimate coke temperature, coke porosity and coke furnace width, and blended coal coke surface breaking strength. Patent Literature 3 discloses a method for accurately estimating the CSR of blended coal coke when blended coal containing non-caking coal or high CRI coal is used. Non-Patent Document 1 discloses that DI and CSR are improved by adding a caking filler.

JP 2011-26514 A JP 2013-1895 A Japanese Patent Application Laid-Open No. 2020-200360

Nishi et al., Tetsu to Hagane 68 (15), 2141-2147 (1982)

None of the prior art documents discloses a technique for achieving both the enlargement of the coke particle size and CSR and the like by adding a low-shrinkage carbonaceous material. Here, when a low-shrinkage carbonaceous material is added to the blended coal, microscopic cracks occur due to the difference in thermal stress due to the difference in contraction rate between the coke matrix portion and the carbonaceous portion. DI decreases as microcracks become defects and start points of fracture. On the other hand, in CSR, in addition to the effect that the microcracks become defects, the surface area of the coke substrate portion increases due to the generation of microcracks, that is, the reaction surface area due to the gasification reaction increases, so the CRI is improved. Therefore, the CSR decreases. As described above, since the DI and CSR lowering mechanisms when adding carbonaceous materials are different from each other, the knowledge disclosed in Patent Document 1 (Technology for expanding the coke grain size by adding low-shrinkage carbonaceous materials and increasing DI ) can be applied to a technology that achieves both the enlargement of the coke grain size by the addition of a low-shrinkage carbonaceous material and CSR.

An object of the present invention is to predict CSR and the like of blast furnace coke produced by carbonizing blended coal to which low-shrinkage carbonaceous materials are added.

In order to solve the above problems, the present invention provides (1) a method for predicting the strength after hot reaction (hereinafter referred to as "CSR") of blast furnace coke produced by carbonizing blended coal to which shrinkage carbonaceous material is added. The degree of influence of the low-shrinkage carbonaceous material coke added to the blended coal on CSR (referred to as “influence degree Ci (CSR)”) is calculated for each predetermined particle size classification of the low-shrinkage carbonaceous material, and these The CSR of blast furnace coke is predicted based on the calculated degree of influence Ci (CSR) of each particle size classification.

The present invention provides (2) a method for predicting the reactivity index (referred to as "CRI") of blast furnace coke produced by carbonizing blended coal to which a low-shrinkage carbonaceous material is added, which is added to blended coal. The degree of influence on the CRI of low-shrinkage carbonaceous coke (referred to as “influence Ci (CRI)”) is calculated for each predetermined particle size classification of low-shrinkage carbonaceous materials, and these calculated influence degrees Ci (CRI), the CRI of blast furnace coke is predicted.

The present invention provides (3) a method for producing blast furnace coke for producing blast furnace coke by carbonizing blended coal to which low-shrinkage carbonaceous material is added, wherein the average grain size of coke when low-shrinkage carbonaceous material is added Based on the first step of predicting the diameter and determining the addition rate of the low-shrinkage carbonaceous material that achieves the predetermined target value of the average coke particle size, and the method of predicting the CSR described in (1) above, A second step of predicting the change in CSR due to the addition of the low-shrinkage carbonaceous material in the first step; and a third step of adjusting the formulation and/or adding a caking filler.

In the present invention, (4) in the second step, the amount of change in coke strength (referred to as "DI") due to the addition of the low-shrinkage carbonaceous material in the first step is predicted, and in the third step, the target CSR of coke and the method for producing blast furnace coke according to the above (3), characterized by adjusting the blended coal blend and/or adding a caking filler in order to satisfy a predetermined target value of DI.

The present invention provides (5) a method for producing blast furnace coke for producing blast furnace coke by carbonizing blended coal to which low-shrinkage carbonaceous material is added, wherein the average grain size of coke when low-shrinkage carbonaceous material is added Based on the first step of predicting the diameter and determining the addition rate of the low-shrinkage carbonaceous material that achieves the predetermined target value of the average coke particle size, and the method of predicting the CRI described in (2) above, A second step of predicting the amount of change in CRI due to the addition of the low-shrinkage carbonaceous material in the first step; and a third step of adjusting the composition.

In the present invention, (6) in the second step, the amount of change in coke strength (referred to as "DI") due to the addition of the low-shrinkage carbonaceous material in the first step is predicted, and in the third step, the target CRI of coke and the step of adjusting the blended coal blend to satisfy a predetermined DI target value, or the step of adjusting the blended coal blend and adding a caking filler. method for producing blast furnace coke.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to predict the CSR and the like of blast furnace coke produced by carbonizing blended coal to which a low-shrinkage carbonaceous material is added.

It is a particle size distribution of coke breeze. MS of coke under conditions 1-7. DI ¹⁵⁰ ₁₅ for coke conditions 1-7. DI ¹⁵⁰ ₆ for coke conditions 1-7. CRI of coke for conditions 1-7. CSR of coke under conditions 1-7.

An embodiment of the present invention will be described. The present invention is based on the premise that a low-shrinkage carbonaceous material that contributes to increasing the coke grain size is added to blended coal. In this specification, a carbonaceous material having a shrinkage rate of 10% or less is defined as a low-shrinkage carbonaceous material.
The shrinkage rate is determined by inserting a low-shrinkage carbonaceous material (sample) into a container and using an electric furnace or the like to heat the sample from room temperature to a temperature T° C. (for example, T=1000° C.) that is sufficiently higher than the resolidification temperature. and the difference between the volume or length of the sample at the resolidification temperature and 1000° C. can be obtained as a value divided by the volume or length at the resolidification temperature. It is recommended that the heating rate be 3° C./min, simulating the heating rate in a coke oven.
Incidentally, the re-solidification temperature is determined by observing the change in displacement of the sample during the heating process using a piston-type shrinkage rate measuring device (see Japanese Patent Application Laid-Open No. 2005-232349), and specifying the temperature at which the change in displacement rapidly increases. be able to.
Since a low-shrinkage carbonaceous material having no softening and melting properties, such as coke breeze, does not resolidify, the shrinkage rate may be measured by the above-described method using room temperature as the resolidification temperature.
As the low-shrinkage carbon material, coke fine, petroleum coke, inert structure, semi-anthracite coal, etc. can be used. For the coke breeze, for example, coke breeze obtained at a steel mill can be used. In addition, when coke fine obtained at a steel mill is added to blended coal, DI, CSR, etc. are lowered. Here, DI in this specification includes _DI ^150-15 and ^DI _150-6 . If there is no particular need to distinguish these DI ¹⁵⁰ ₁₅ and DI ¹⁵⁰ ₆ , they may be collectively referred to as DI. DI ¹⁵⁰ ₁₅ is the 15 mm sieve index after 150 drum rotations, and DI ¹⁵⁰ ₆ is the 6 mm sieve index after 150 drum rotations.

(First embodiment)
An embodiment of a method of predicting CSR (strength after hot reaction of coke) will be described. The degree of influence of low-shrinkage carbonaceous coke added to blended coal on CSR (hereinafter also referred to as “degree of influence Ci (CSR)”) is calculated for each predetermined particle size division, and these calculated particle size divisions are calculated. The CSR of blast furnace coke is predicted based on the degree of influence Ci (CSR). The degree of influence Ci (CSR) differs depending on the type of low-shrinkage carbonaceous material, and even with the same type, it differs depending on the grain size. Therefore, it is necessary to determine the degree of impact Ci (CSR) in association with the type and grain size classification of the low-shrinkage carbonaceous material. The types of carbonaceous material can be classified according to the volatile content VM, which is related to the shrinkage rate, which is the property of the carbonaceous material.

Specifically, the CSR is actually measured for each of blended coal (with addition of low-shrinkage carbon material) and blended coal (without addition of low-shrinkage carbon material). The actual measurement method of CSR is as follows. Coke is obtained by carbonizing the coal blend in a test carbonization furnace, and 200 g of coke adjusted to a size of 20 ± 1 mm is subjected to predetermined conditions (gas composition: 100% carbon dioxide, reaction temperature 1100 ° C., reaction time 2 hours). and after 600 revolutions in an I-shaped drum, the percentage of the mass after the reaction on a 9.56 mm sieve can be taken as CSR.

The difference between CSR (with addition of low-shrinkage carbon material) and CSR (without addition of low-shrinkage carbon material) (hereinafter also referred to as differential CSR) is obtained from the actual measurement results, and this difference CSR is used as the addition rate of low-shrinkage carbon material Y (external number) to calculate the degree of influence Ci (CSR). By performing these operations for each type of low-shrinkage carbonaceous material and particle size division, it is possible to obtain the degree of impact Ci (CSR) associated with the type and particle size division. Since there is a tendency that the finer the grain size division, the more accurate the grain size is, and therefore the grain size range of 0.1 mm to 1.0 mm is desirably divided into at least three divisions. In the actual process, an appropriate grain size division should be set while observing the error from the actual measurement value.

Next, the particle size distribution of the low-shrinkage carbonaceous material used for the production of coke to be used in the blast furnace is examined, and the ratio bi of the low-shrinkage carbonaceous material belonging to each particle size division is obtained. The ratio bi of the low-shrinkage carbonaceous material can be a ratio when the mass of the entire low-shrinkage carbonaceous material is 1. Multiplying the ratio bi of the low-shrinkage carbonaceous material for each particle size classification by the degree of influence Ci (CSR) obtained by the above method, adding them up, and then multiplying the addition rate Y of the low-shrinkage carbonaceous material yields Δφ (CSR change) can be obtained. When this is made into a general formula, it is as follows.

The CSR of coke to be used in the blast furnace can be predicted by adding the CSR variation Δφ obtained based on Equation 1 to the CSR (without addition of low-shrinkage carbonaceous material). Since the low-shrinkage carbonaceous material acts in the direction of lowering the CSR of coke, Δφ becomes a negative value.

(Second embodiment)
An embodiment of a CRI (coke reactivity index) prediction method will be described. The degree of influence of low-shrinkage carbonaceous coke added to blended coal on CRI (hereinafter also referred to as “degree of influence Ci (CRI)”) is calculated for each predetermined particle size division, and these calculated particle size divisions are calculated. Based on the degree of influence Ci (CRI), the CRI of coke to be used in the blast furnace is predicted. The degree of influence Ci (CRI) differs for each type of low-shrinkage carbonaceous material, and even for the same type, it differs depending on the grain size. Therefore, it is necessary to determine the degree of impact Ci (CRI) in association with the type and grain size classification of the low-shrinkage carbonaceous material.

Specifically, the CRI is measured for each of blended coal (with addition of low-shrinkage carbon material) and blended coal (with no addition of low-shrinkage carbon material). The actual measurement method of CRI is as follows. Coke is obtained by test carbonization of blended coal, and 200 g of coke sized to a size of 20 ± 1 mm is reacted under predetermined conditions (gas composition: 100% carbon dioxide, reaction temperature 1100 ° C., reaction time 2 hours). After the reaction, the mass after reaction is measured, and can be obtained from the calculation formula "CRI = (mass before reaction - mass after reaction)/mass before reaction x 100".

The difference between CRI (with addition of low-shrinkage carbon material) and CRI (without addition of low-shrinkage carbon material) (hereinafter also referred to as difference CRI) is obtained from the actual measurement results, and this difference CRI is used as the addition rate Y (external number ) to calculate the influence Ci (CRI). By performing these operations for each type of low-shrinkage carbonaceous material and particle size classification, it is possible to obtain the degree of influence Ci (CRI) associated with the type of carbonaceous material and particle size classification. The granularity classification can be appropriately set as in the first embodiment.

Next, the particle size distribution of the low-shrinkage carbonaceous material used for the production of coke to be used in the blast furnace is examined, and the ratio bi of the low-shrinkage carbonaceous material belonging to each particle size division is obtained. The ratio bi of the low-shrinkage carbonaceous material can be a ratio when the mass of the entire low-shrinkage carbonaceous material is 1. Multiplying the ratio of the low-shrinkage carbonaceous material for each particle size classification by the degree of influence Ci (CRI) obtained by the above method, adding them up, and then multiplying the addition rate Y of the low-shrinkage carbonaceous material yields Δφ (CRI ) can be obtained. The general formula is the same as Formula 1 of the first embodiment.

The CRI of coke to be used in a blast furnace can be predicted by adding the variation Δφ of CRI obtained based on Equation 1 to the CRI (without addition of low-shrinkage carbonaceous material). Δφ is a positive value because the low-shrinkage carbonaceous material acts to increase the CRI of coke.

(Third embodiment)
The method for producing blast furnace coke according to the present embodiment includes the following steps.
(Step S1-1)
In step S1-1, the addition rate of the low-shrinkage carbonaceous material to be added to the blended coal is determined. That is, the average particle size of coke (hereinafter also referred to as MS of coke) when a low-shrinkage carbonaceous material is added is predicted, and a predetermined target value for the average particle size of coke (hereinafter referred to as target MS) is achieved. Determine the addition rate of low-shrinkage carbonaceous material to be used. A known method can be used to predict the MS of coke when a low-shrinkage carbonaceous material is added. For example, as described in Patent Document 1, the MS of coke can be predicted by considering the degree of influence of the type and length of the low-shrinkage carbonaceous material.

(Step S1-2)
In step S1-2, the amount of change in CSR that changes (decreases) due to the addition of the low-shrinkage carbonaceous material according to the addition rate in step S1-1 is determined. The method described in the first embodiment can be used as the method for determining the change margin of CSR.

(Step S1-3)
Coal blend adjustments and/or caking fillers are added to meet predetermined coke target CSR. Here, the target CSR can be set equal to or higher than the CSR of coke not using low-shrinkage carbonaceous materials. That is, by adjusting the blended coal blend and/or adding a caking filler, only the amount of change in CSR may be compensated, or the amount of change may be compensated to exceed the amount of change. Here, blending adjustment of blended coal means adjusting the blending ratio of coals constituting blended coal such as coking coal and non-slightly coking coal. In addition, caking fillers include petroleum-based caking agents (ASP, etc.), coal-based caking agents (tar, pitch, SRC (Solvent Refined Coal), etc.), and other highly aromatic, softening and melting materials. A polymeric substance or the like having properties can be used.

By investigating in advance the relationship between blending adjustment of blended coal and addition of caking filler and CSR, it is possible to determine the method of blending adjustment of blended coal and the amount of addition of caking filler. Note that a known method (for example, the method disclosed in Patent Document 2) can be used for adjusting the blend of blended charcoal. Moreover, the addition amount of the caking filler material can be determined using a known method (for example, the method disclosed in Non-Patent Document 1).

According to this embodiment, the target CSR can be achieved while increasing the coke grain size by adding the low-shrinkage carbonaceous material.

(Fourth embodiment)
The method for producing blast furnace coke according to the present embodiment includes the following steps.
(Step S2-1)
In step S2-1, the addition rate of the low-shrinkage carbonaceous material to be added to the blended coal is determined. Since this point is the same as step S1-1 in the third embodiment, detailed description will be omitted.
(Step S2-2)
In step S2-2, the amount of change in CSR that changes (decreases) due to the addition of the low-shrinkage carbonaceous material according to the addition rate in step S2-1 is determined. Since this point is also the same as step S1-2 in the third embodiment, detailed description is omitted.

(Step S2-3)
Step S2-3 is a process performed together with step S2-2, and determines the amount of change in DI that changes (decreases) by adding the low-shrinkage carbonaceous material according to the addition rate of step S2-1. As a method for calculating the amount of change in DI, the same method as the method for obtaining the amount of change in CSR or CRI described above, or a known method can be used.

(Step S2-4)
Actions are taken to adjust the blended coal blend and/or add caking fillers to meet the coke target CSR and the predetermined coke target DI. As in the third embodiment, the target CSR can be set equal to or higher than the CSR of coke that does not use low-shrinkage carbonaceous materials. Also, the target DI of coke can be set to be the same as or higher than the DI of coke that does not use the low-shrinkage carbonaceous material.

According to this embodiment, the target CSR and the target DI can be achieved while enlarging the coke particle size by adding the low-shrinkage carbonaceous material.

(Fifth embodiment)
The method for producing blast furnace coke according to the present embodiment includes the following steps.
(Step S3-1)
In step S3-1, the addition rate of the low-shrinkage carbonaceous material to be added to the blended coal is determined. Since this point is the same as step S1-1 in the third embodiment, detailed description will be omitted.

(Step S3-2)
In step S3-2, the amount of change in CRI that changes (increases) by adding the low-shrinkage carbonaceous material according to the addition rate in step S3-1 is determined. Since the method of determining the CRI variation has been described in the second embodiment, detailed description thereof will be omitted.

(Step S3-3)
Coal blend adjustments are made to meet the target CRI of coke. Here, the target CRI can be set equal to or lower than the CRI of coke not using the low-shrinkage carbonaceous material. In other words, the action of this step is not limited to the process of decreasing only the amount of increase in CRI, but also includes the process of decreasing the amount beyond the amount of increase.

By investigating the relationship between blending adjustment of blended coal and CRI in advance, it is possible to determine the adjustment degree of blending adjustment of blended coal.

According to this embodiment, the target CRI can be achieved while increasing the coke particle size by adding the low-shrinkage carbonaceous material.

(Sixth embodiment)
The method for producing blast furnace coke according to the present embodiment includes the following steps.
(Step S4-1)
In step S4-1, the addition rate of the low-shrinkage carbonaceous material to be added to the blended coal is determined. Since this point is the same as step S1-1 in the third embodiment, detailed description will be omitted.

(Step S4-2)
In step S4-2, the amount of change in CRI that changes (increases) by adding the low-shrinkage carbonaceous material according to the addition rate in step S4-1 is determined. Since the method of determining the CRI variation has been described in the second embodiment, detailed description thereof will be omitted.

(Step S4-3)
Step S4-3 is a process performed together with step S4-2, and determines the amount of change in DI that changes (decreases) by adding the low-shrinkage carbonaceous material according to the addition rate of step S4-1. As a method for calculating the amount of change in DI, the same method as the method for obtaining the amount of change in CSR or CRI described above, or a known method can be used.

(Step S4-4)
In order to satisfy the target CRI of coke and the predetermined target DI of coke, the coal blend may be adjusted, or a caking filler may be added along with the coal blend adjustment. As in the fifth embodiment, the target CRI can be set equal to or lower than the CRI of coke not using low-shrinkage carbonaceous materials. Also, the target DI of coke can be set to be the same as or higher than the DI of coke that does not use the low-shrinkage carbonaceous material.

According to this embodiment, the target CRI and the target DI can be achieved while enlarging the coke particle size by adding the low-shrinkage carbonaceous material.

配合炭は、粒度が３ｍｍ以下８５質量％となるように粒度調整し、ΣＶＭは２９．２質量％、ΣＴＤは１１３．４％であった。なお、ΣＶＭ及びΣＴＤは質量による加重平均で求めた。 (Example)
The present invention will be specifically described with reference to examples. Coke was produced by adding various coke fines (low-shrinkage carbonaceous material) with different particle sizes to blended coal, and carbonizing them in a test coke oven. Table 1 shows the properties and blending ratios of each coking coal contained in the blended coal. VM (mass %) is volatiles and TD (%) is total expansion.

The particle size of the blended coal was adjusted so that the particle size was 3 mm or less and 85% by mass, and ΣVM was 29.2% by mass and ΣTD was 113.4%. Note that ΣVM and ΣTD were determined by weighted average by mass.

Table 2 shows the coke breeze addition conditions (conditions 1 to 7). In Condition 1, coke breeze was not added. In condition 2, coke breeze (coke breeze according to the particle size distribution in FIG. 1) generated from a steel factory was added to the blended coal. In conditions 3 to 7, coke fine generated from a steel factory was adjusted in particle size with a predetermined sieve and added to blended coal. The addition rate of coke breeze was 2% by mass (outside number).

The size of the carbonization vessel of the test coke oven was oven width (W): 400 mm, oven length (L): 600 mm, and oven height (H): 420 mm. The charged bulk density of coal was 850 (kg/m ³ ) on a dry basis. The ultimate temperature of the test coke oven was set to 1150°C, and the carbonization time was set to 18.5 (hours).

また、図１に示す粉コークスの粒度構成を、表４に示した。

Each coke was processed by a drum tester according to "JIS K2151", and MS of coke was determined from samples larger than 25 mm after 30 revolutions, and DI ¹⁵⁰ ₁₅ and DI ¹⁵⁰ ₆ from samples after 150 revolutions. The CRI and CSR of coke were measured by the methods already described in the embodiments. Measured values of MS, DI ¹⁵⁰ ₁₅ , DI ¹⁵⁰ ₆ , CRI and CSR of each coke are shown in FIGS. Moreover, these results are summarized in Table 3.

Table 4 shows the particle size composition of the coke breeze shown in FIG.

For each of MS, DI ¹⁵⁰ ₁₅ , DI ¹⁵⁰ ₆ , CSR and CRI of coke, by subtracting the measured value of condition 1 from the measured value of conditions 3 to 7 and dividing it by the addition rate of low shrinkage carbonaceous material, The degree of influence Ci of each particle size classification of coke breeze was determined. The results are shown in Table 5. For example, when determining the degree of influence Ci (CSR) of coke fine (particle size: less than 0.1 mm) under condition 3, referring to Table 3, CSR under condition 3 (39.8) to CSR under condition 1 (44. 5) is subtracted to obtain the difference (-4.7), and this difference (-4.7) is divided by the coke breeze addition rate (2% by mass) to obtain the degree of influence Ci (CSR) as "-2. 4” was calculated. Other degrees of influence Ci were also calculated by the same method.

いずれも、予測値と実測値との誤差が非常に小さいことを確認した。 Next, based on the formula for calculating Δφ described above, for each of MS, DI ¹⁵⁰ ₁₅ , DI ¹⁵⁰ ₆ , CSR, and CRI of coke, the amount of change was obtained, and then the predicted value was calculated. The results are shown in Table 6. Taking CSR as an example, the procedure for calculating the amount of change and the predicted value will be described. First, the ratio of each particle size category shown in Table 4 was replaced with the ratio when the mass of the entire coke breeze was 1 (that is, the ratio in Table 4 was multiplied by 0.01). Then, each ratio is multiplied by each influence Ci (CSR) in Table 5 to obtain the sum of these, and then multiplied by the addition rate of coke breeze (addition rate: 2%) to obtain the CSR change △ φ was obtained. By adding the obtained variation Δφ to the CSR (44.5) of Condition 1, the CSR was predicted to be “36.9”. The CSR of Condition 1 is the CSR of coke to which no low-shrinkage carbonaceous material is added. These predicted values are shown in Table 6 together with actual values. In Table 6, "Not added" is a repeat of "Condition 1" in Table 3, and "Actual value" in Table 6 is a repeat of "Condition 2" in Table 3.

In both cases, it was confirmed that the error between the predicted value and the measured value is very small.

本発明者等が調べたところ、粘結補填材Ａの添加率を１％上げると、ＤＩ^１５０ _１５が０．３２ｐｔ上昇するとともに、ＣＳＲが２．２ｐｔ上昇することがわかった。ここで、表６の「未添加」及び「予測値」の差分から粉コークス添加によるＤＩ^１５０ _１５及びＣＳＲの低下代がそれぞれ１．４ｐｔ及び７．６ｐｔと推算できる。したがって、ＤＩ^１５０ _１５の低下代を補填するために必要な粘結補填材Ａの添加量は４．３％、ＣＳＲの低下代を補填するために必要な粘結補填材Ａの添加量は３．４％と算出できる。よって、ＤＩ^１５０ _１５及びＣＳＲの低下代を共に無くすためには、粘結補填材Ａを４．３％添加すればよいことがわかる。ただし、上述したように、低下代を超えるように粘結補填材を添加してもよい。すなわち、低収縮炭材未添加のコークスのＣＳＲ等よりも目標値が高い場合には、低下代を超えるように粘結補填材を添加することにより、目標値を満足させてもよい。
Here, a method of supplementing CSR and DI ¹⁵⁰ ₁₅ by adding caking filler material A having the properties shown in Table 7 below was investigated.

As a result of investigation by the present inventors, it was found that when the addition rate of caking filler material A was increased by 1%, DI ¹⁵⁰ ₁₅ increased by 0.32pt and CSR increased by 2.2pt. Here, from the difference between "not added" and "predicted value" in Table 6, the reduction of DI ¹⁵⁰ ₁₅ and CSR due to the addition of coke breeze can be estimated to be 1.4pt and 7.6pt, respectively. Therefore, the amount of caking filler A required to compensate for the decrease in DI ¹⁵⁰ ₁₅ is 4.3%, and the amount of caking filler A required to compensate for the decrease in CSR is 3. .4%. Therefore, it can be seen that 4.3% of the caking filler material A should be added in order to eliminate both DI ¹⁵⁰ ₁₅ and the reduction of CSR. However, as described above, the caking filler may be added so as to exceed the lowering margin. That is, when the target value is higher than the CSR of coke to which low-shrinkage carbonaceous material is not added, the target value may be satisfied by adding a caking filler so as to exceed the lowering allowance.

Claims (6)

A method for predicting the strength after hot reaction (referred to as "CSR") of blast furnace coke produced by carbonizing blended coal to which low-shrinkage carbonaceous material is added, comprising:
The degree of influence of low-shrinkage carbonaceous material coke added to blended coal on CSR (referred to as “influence degree Ci (CSR)”) is calculated for each predetermined particle size category of low-shrinkage carbonaceous material, and these calculated particle sizes A method of predicting the CSR of blast furnace coke based on the degree of impact Ci (CSR) of the category. A method for predicting the reactivity index (referred to as "CRI") of blast furnace coke produced by carbonizing blended coal to which low-shrinkage carbonaceous material is added, comprising:
The degree of influence of the low-shrinkage carbonaceous material coke added to the blended coal on the CRI (referred to as “influence degree Ci (CRI)”) is calculated for each predetermined particle size division of the low-shrinkage carbonaceous material, and these calculated particle sizes A method of predicting the CRI of blast furnace coke based on the degree of impact Ci (CRI) of the category. A method for producing blast furnace coke for producing blast furnace coke by dry distillation of blended coal to which low-shrinkage carbonaceous material is added,
a first step of predicting the average particle size of coke when adding a low-shrinkage carbonaceous material and determining the addition rate of the low-shrinkage carbonaceous material that achieves a predetermined target value for the average particle size of coke;
a second step of predicting a change in CSR due to the addition of the low-shrinkage carbonaceous material in the first step, based on the method of predicting CSR according to claim 1;
a third step of adjusting the blended coal blend and/or adding a caking filler to satisfy a predetermined coke CSR target value (referred to as "coke target CSR");
A method for producing blast furnace coke, comprising: In the second step, predicting the amount of change in coke strength (referred to as "DI") due to the addition of the low-shrinkage carbonaceous material in the first step,
4. The method according to claim 3, wherein, in the third step, blending adjustment of blended coal and/or caking filler is added in order to satisfy the target CSR of coke and the predetermined target value of DI. A method for producing blast furnace coke. A method for producing blast furnace coke for producing blast furnace coke by dry distillation of blended coal to which low-shrinkage carbonaceous material is added,
a first step of predicting the average particle size of coke when adding a low-shrinkage carbonaceous material and determining the addition rate of the low-shrinkage carbonaceous material that achieves a predetermined target value for the average particle size of coke;
a second step of predicting a change in CRI due to the addition of the low-shrinkage carbonaceous material in the first step, based on the method of predicting CRI according to claim 2;
a third step of adjusting the blended coal to satisfy a predetermined CRI target value of coke (referred to as "coke target CRI");
A method for producing blast furnace coke, comprising: In the second step, predicting the amount of change in coke strength (referred to as "DI") due to the addition of the low-shrinkage carbonaceous material in the first step,
In the third step, the step of adjusting the blended coal blend to satisfy the target CRI of coke and the predetermined target value of DI, or the step of adjusting the blended coal blend and adding a caking filler is performed. The method for producing blast furnace coke according to claim 5, characterized in that:

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