METHOD FOR ESTIMATING COKE STRENGTH AND METHOD FOR PRODUCING COKE
Patent Information
- Application Number
- BR112025019946
- Authority / Receiving Office
- BR · BR
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-28
- Filing Date
- 2023-11-07
- Publication Date
- 2026-08-04
Smart Images
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Abstract
Description
[001] The present invention relates to a method for estimating the strength of coke produced by carbonizing a coal mixture containing briquettes and powdered coal, with non-binding or slightly binding coal, with low binding properties, being mixed with the briquettes, and the present invention also relates to a method for producing coke. Antecedent Technique
[002] The coke that is loaded into blast furnaces needs to have high strength. Consequently, coal with high agglutination properties, from which high-strength coke can be produced, is preferentially used as a feedstock for coke. However, the coal that is mined is not limited to coal with high agglutination properties, and includes coal with low agglutination properties. Consequently, it is common practice to prepare a coal blend by mixing various types (grades) of coal with different properties and to use the coal blend as a feedstock for coke. The agglutination property of coal is a property in which coal melts and solidifies during carbonization, and is a crucial property for coke production.Since the agglutination property is determined by the properties of coal exhibited when the coal is thermally plasticized, an effective way to assess the suitability of a coal grade as a feedstock for coke is to use, as an index, values (measured values or estimated values) associated with the thermoplasticity of the coal.
[003] In many cases, coal with high agglutination properties is expensive, while coal with low agglutination properties is cheap. Therefore, an effective way to reduce the cost of ma Petition 870250084130, dated 09 / 18 / 2025, pp. 51 / 91 2 / 35 of the raw material is to actively use, as a raw material for coke, so-called unbound or slightly bound coal, which has low binding properties.
[004] Techniques for effectively using non-agglomerating or slightly agglomerating coal as feedstock for coke include the briquette blending method. Coke is typically produced by carbonizing coal fines in a coke oven; the coal fines are obtained by pulverizing the coal that serves as feedstock, so that, for example, the coal fines may include particles with a size of 3 mm or less in an amount of 70 to 100% by mass. The briquette blending method produces coke by briquetting a portion of the powdered coal to be loaded into a coke oven and then, in the coke oven, carbonizing a coal mixture containing the briquettes mixed with the coal fines.
[005] Because briquettes are compacted compared to coal fines, the coal particles that form the briquettes are close to each other. Consequently, even coal with low agglutination properties will likely undergo fusion and bonding between the coal particles due to heating, and consequently, the strength of the coke is improved. Therefore, with the briquette mixing method, the strength of the coke can be maintained even with the use of a larger quantity of coal without agglutination or with light agglutination, which has a lower agglutination property.
[006] In the case of a coal mixture containing briquettes mixed with coal fines being carbonized, often the same coal composition is used in the briquette portion and in the coal fines portion, and a binder material is added to the briquette portion for briquetting. In some cases, however, the coal used Petition 870250084130, dated 09 / 18 / 2025, p. 52 / 91 3 / 35 used in the briquette portion may be different from the coal used in the coal fines portion.
[007] It is known empirically that the strength of the coke produced varies depending on the grade of non-agglutinating or slightly agglutinating coal. One reason for this is the low accuracy associated with evaluating coal with low agglutinating properties.
[008] The evaluation of the agglutination property of coal is frequently performed with a Gieseler plastometer, as specified in JIS M 8801:2008. This method is performed as follows: coal is loaded into a container including an agitator, a constant torque is applied to the agitator while the coal is heated, and the thermoplasticity of the coal is evaluated based on the maximum rotation speed (expressed as the maximum flowability ddpm) of the agitator. If the maximum flowability of non-agglutinating or slightly agglutinating coal is low, however, the superiority or inferiority of non-agglutinating or slightly agglutinating coal cannot be evaluated with sufficient precision. One reason for this is believed to be the following: although the Gieseler maximum flowability MF has a measurable range from 0 to approximately 50.If the melting point (MF) of coal generally referred to as non-agglutinating or slightly agglutinating coal is approximately 100 ddpm or less, it is difficult to assess superiority or inferiority with sufficient precision, as the assessment uses a semi-logarithmic graph plotting temperature versus the common logarithm of Gieseler's maximum melting point (log MF). Furthermore, there are many types of non-agglutinating or slightly agglutinating coal with an MF of 0 (coal with an MF of 0 is sometimes referred to as non-agglutinating coal), and if these types of non-agglutinating coal are used as feedstocks for coke, it is difficult to assess the differences in agglutination property. Petition 870250084130, dated 09 / 18 / 2025, pp. 53 / 91 4 / 35
[009] Patent Literature 1 describes, as a technique for evaluating the agglutination property of non-agglutinating or slightly agglutinating coal, which has low agglutination property, as mentioned above, a method in which the Gieseler flowability is measured after the addition of a primary or secondary amine-based compound with an aromatic ring to the coal. The addition of a primary or secondary amine-based compound with an aromatic ring to the coal improves the flowability and, therefore, even if the maximum Gieseler flowability MF of the non-agglutinating or slightly agglutinating coal is 0 ddpm, measured in a state where only coal is present, the maximum Gieseler flowability MF, measured after the addition of an amine, shows a change.Furthermore, Patent Literature 1 describes that the strength of coke, in the case where non-binding or slightly binding coal is added to coal fines, shows a good correlation with the maximum Gieseler flowability, measured after the addition of a primary or secondary amine-based compound with an aromatic ring. That is, Patent Literature 1 states that flowability as measured after the addition of an amine can be an index for evaluating the superiority or inferiority of non-binding or slightly binding coal as a feedstock for coke. List of citations Patent Literature
[0010] PTL 1: International Publication No. 2016 / 136191 Summary of the invention Technical problem
[0011] Unfortunately, in the case of coke produced by mixing non-binding or slightly binding coal in briquettes and using the briquettes, there is the problem that, even if the coal used is evaluated as usable by the Literature method of Petition 870250084130, dated 09 / 18 / 2025, pp. 54 / 91 5 / 35 Patent 1, the production of coke with the target strength is not achieved. The present invention was developed in view of this problem, and one of the objectives of the present invention is to provide a method for estimating the strength of coke that allows the estimation of the strength of coke even in cases where non-binding or slightly binding coal is mixed with the briquettes. Another objective of the present invention is to provide a method for the production of coke that uses the method for estimating the strength of coke. Solution to the problem
[0012] The means to solve the problem are as follows.
[0013] [1] A method for estimating the strength of coke, the method including estimating the strength of coke produced by carbonizing a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein, in the coal mixture that is carbonized to produce the coke, the briquettes are in a state of being partially pulverized, and the strength of the coke is estimated using a strength of the coke produced by carbonizing a different coal mixture containing briquettes and powdered coal and wherein the briquettes are in a state of not being pulverized; a mixing ratio of the briquettes mixed in the coal mixture; a strength of the briquettes; a mixing ratio of the non-binding or slightly binding coal mixed with the briquettes;and the thermoplasticity of a mixture containing non-binding or slightly binding charcoal with at least one compound added to it, the at least one compound being selected from primary amine compounds and secondary amine compounds, the primary amine compounds and the secondary amine compounds each having an aromatic ring.
[0014] [2] A method for producing coke, the method including Petition 870250084130, dated 09 / 18 / 2025, pp. 55 / 91 6 / 35 production of coke by carbonization of a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein the method includes making an adjustment to prepare the briquettes and / or prepare the coal mixture so that a coke strength equal to or greater than a predetermined coke strength is achieved, the coke strength being estimated by the method for estimating a coke strength according to [1], the adjustment including the adjustment of at least one coke strength of the coke that is produced by carbonization of a different coal mixture containing the briquettes and powdered coal and in which the briquettes are in a non-pulverized state; the mixing ratio of the briquettes mixed in the coal mixture; the strength of the briquettes; the mixing ratio of the non-binding or slightly binding coal mixed with the briquettes;and the thermoplasticity of the mixture containing non-binding or slightly binding coal with at least one compound added to it, the at least one compound being selected from primary amine compounds and secondary amine compounds, the primary amine compounds and the secondary amine compounds each having an aromatic ring, and producing coke by carbonization of the prepared coal mixture.
[0015] [3] A method for producing coke, the method including the production of coke by carbonization of a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein the method includes measuring a maximum Gieseler flowability MF of the non-binding or slightly binding coal after adding 1 part by mass of N,N'-di-2-naphthyl-p-phenylenediamine to 10 parts by mass of the non-binding or slightly binding coal; preparing the coal mixture so that a ratio of non-binding coal mixture Petition 870250084130, dated 09 / 18 / 2025, pp. 56 / 91 7 / 35 non-binding or slightly binding coal having a common logarithm of the maximum Gieseler flowability of 3.0 or less that is present in the briquettes is greater than a mixing ratio of non-binding or slightly binding coal having a common logarithm of the maximum Gieseler flowability of 3.0 or less that is present in the powdered coal; and produce coke by carbonization of the prepared coal mixture. Advantageous effects of the invention
[0016] With the method for estimating coke strength according to the present invention, it is possible to estimate, with high precision, the strength of coke produced with a mixture of coal containing briquettes and powdered coal, wherein the briquettes contain non-binding or slightly binding coal mixed with them and are in a partially pulverized state. Producing coke with this method for estimating coke strength allows for the production of coke with a target coke strength. Furthermore, reductions in the cost of coke production can also be achieved, as a larger quantity of non-binding or slightly binding coal, which has low binding properties and is inexpensive, can be used while the target coke strength is achieved. Brief description of the drawings
[0017] Figure 1 is a graph illustrating a relationship between a log CATMF of non-binding or slightly binding coal included in briquettes and a coke strength of coke produced with a coal mixture containing briquettes mixed with coal fines.
[0018] Figure 2 is a graph illustrating a relationship between the log CATMF of non-agglutinating or slightly agglutinating coal included in coal fines and the coke strength of coke produced with Petition 870250084130, dated 09 / 18 / 2025, pp. 57 / 91 8 / 35 the fine coal particles.
[0019] Figure 3 is a graph that illustrates the relationship between the briquette pulverization ratio and the coke strength of the coke produced by mixing briquettes with coal fines.
[0020] Figure 4 is a graph illustrating a relationship between the log CATMF of non-binding or slightly binding coal mixed in briquettes and the amount of decrease in coke strength per 1% mass of pulverization ratio. Description of the Modalities
[0021] The present invention will now be described with reference to embodiments of the present invention. A method for estimating the coke strength of the present embodiment estimates the coke strength of coke that is produced by carbonizing a coal mixture containing briquettes (which may be briquettes in a partially pulverized state) and pulverized coal (which may be referred to as coal fines in the description below), wherein the briquettes contain non-binding or slightly binding coal mixed with them. The method uses five parameters, listed below. 1. Coke strength (DIbase) of coke produced by carbonizing a mixture of different coal containing briquettes and powdered coal, where the briquettes are in a non-pulverized state. 2. Mixing ratio (Wbq) of briquettes mixed in the coal mixture 3. Resistance (Sbq) of the briquettes 4. Mixing ratio (Wncc) of non-agglomerating or slightly agglomerating coal mixed with briquettes 5. Thermoplasticity (CATP) of a mixture containing non-binding or slightly binding charcoal with a primary amine compound or a secondary amine compound added to Petition 870250084130, dated 09 / 18 / 2025, pp. 58 / 91 9 / 35 it, the compound having an aromatic ring
[0022] First, the circumstances under which the method for estimating the strength of coke in the present embodiment was invented will be described.
[0023] The inventors investigated the coke strength of coke produced with briquettes containing non-binding or slightly binding coal and the coke strength of coke produced with coal fines containing non-binding or slightly binding coal. As a result, the inventors found that, although the binding property of non-binding or slightly binding coal can be evaluated by measuring the Gieseler flowability after the addition of an amine, the influence of non-binding or slightly binding coal on the strength of the coke produced with non-binding or slightly binding coal differs between when non-binding or slightly binding coal is present in briquettes and when it is present in coal fines. Consequently, the inventors invented the method for estimating the strength of the coke of the present embodiment.
[0024] A coke production trial that investigated the influence of non-binding or slightly binding coal on coke strength will be described. The properties of eight types of non-binding or slightly binding coal (T1 to T8) that were used in the coke production trial are shown in Table 1 below. Table 1 MF (ddpm) Ro (%) TI (% by volume) CATMF (ddpm) Log CATMF (log [ddpm]) T1 0 1.46 37.0 6310 3.80 T2 0 1.29 64.9 550 2.74 T3 0 1.36 60.4 195 2.29 T4 0 1.71 58.6 0 - Petition 870250084130, dated 09 / 18 / 2025, pp. 59 / 91 10 / 35 MF (ddpm) Ro (%) TI (% by volume) CATMF (ddpm) Log CATMF (log [ddpm]) T5 0 1.79 45.2 9 0.95 T6 0 1.54 40.7 295 2.47 T7 0 1.52 38.0 6607 3.82 T8 0 1.30 45.7 2089 3.32
[0025] In Table 1 above, MF is the maximum flow MF of Gieseler (ddpm) determined by the method specified in JIS M 8801:2008. Ro is the maximum vitrinite average reflectance (%) of the coal, as determined by the method specified in JIS M 8816:1992. TI is the total inert (% by volume) calculated using the amounts of coal macerals determined by the method specified in JIS M 8816:1992 and using equation (1), shown below, which is based on the Parr equation described in an explanation of the method. TI (% by volume) = fusinite (% by volume) + micrinite (% by volume) + (2 / 3)xsemifusinite (% by volume) + mineral matter (% by volume) (1)
[0026] CATMF in Table 1 is the maximum flowability (ddpm) of a mixture measured according to the measurement method specified in JIS M 8801:2008. The mixture was prepared by adding 1 part by mass (0.5 g) of N,N'-di-2-naphthyl-p-phenylenediamine to 10 parts by mass (5 g) of charcoal, according to the method described in Patent Literature 1. In the present embodiment, CATMF is the maximum flowability measured under these conditions. For reference, the common logarithm of CATMF, denoted as log CATMF, is shown in the column to the right of CATMF. CATMF is an example of thermoplasticity (CATP) of the aforementioned mixture containing non-binding or slightly binding charcoal with a primary amine compound or a secondary amine compound added to it, the compound having an aromatic ring.
[0027] All types of non-agglomerating or slightly clumping coal Petition 870250084130, dated 09 / 18 / 2025, pp. 60-91 The 11 / 35 binder coals (T1 to T8) shown in Table 1 have a fluid mass (FM) of 0 ddpm and are therefore coals that do not exhibit flowability under the measurement method specified in JIS M 8801:2008. However, measurements of the mixture containing non-binding or slightly binding coal with added N,N'-di-2-naphthyl-p-phenylenediamine indicate that even non-binding or slightly binding coal exhibits flowability and that the fluidity CATMF associated with the addition of an amine varies depending on the grade of non-binding or slightly binding coal. The CATMF values in Table 1 indicate that, among the types of non-binding or slightly binding coal (T1 to T8), T7 and T1 are coals with high binding properties, and T4 and T5 are coals with low binding properties.
[0028] The amine used to improve the flowability of charcoal is not limited to N,N'-di-2-naphthyl-p-phenylenediamine, which was used in the assay described above. Any other amine may be used, provided it is a primary or secondary amine-based compound with an aromatic ring that can be added to charcoal to improve its flowability. Furthermore, the amine may not necessarily be a single amine, but rather a mixture of two or more amines. Specifically, phenothiazines, carbazoles, N-phenyl-1-naphthylamine, and the like may be used. Additionally, the ratio of the added amine may be altered for the evaluation of the flowability of non-agglutinating or slightly agglutinating charcoal.
[0029] Now, the strength of the coke produced by making briquettes containing non-binding or slightly binding coal mixed with them, the preparation of a coal mixture in which the briquettes are mixed with coal fines that do not contain non-binding or slightly binding coal mixed with them, and the carbonization of the coal mixture will be described. The composition of the briquettes used in the production of coke is shown. Petition 870250084130, dated 09 / 18 / 2025, pp. 61 / 91 12 / 35 in Table 2 below. All types of coal used in the briquettes were pulverized so that all particles had a size of 3 mm or less (all particles passed through a 3 mm sieve opening). In the present embodiment, the mixing ratio is a % by mass on a dry basis. Table 2 Coal Types Mixing Ratio (% by mass) Non-agglutinating or slightly agglutinating coal (one of T1 to T8) 20 B1 40 B2 13 B3 13 B4 10 TARP 4
[0030] In Table 2 above, B1 to B4 are coal types with binding properties, and TARP is a heavy pitch derived from coal tar and added as a binding agent. The properties of coals B1 to B4 are shown in Table 3 below. Table 3 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) B1 2.47 0.72 24.7 B2 1.32 1.27 44.3 B3 1.48 1.00 47.6 B4 2.73 1.01 33.4
[0031] In Table 3, log MF is the common logarithm of the maximum flow rate MF (log [ddpm]) measured by the measurement method specified in JIS M 8801:2008, and Ro and TI are the same as in Table 1.
[0032] Soft pitch (SOP) based on tar and coal tar were added as binders in amounts of 0.5% by mass and 6% by mass, respectively, based on the total mass of the various types of coal that were mixed in the proportions listed in Ta Petition 870250084130, dated 09 / 18 / 2025, pp. 62 / 91 13 / 35 beautiful 2 above. The resulting material was kneaded for 1.5 minutes while being heated with steam injection. In this state, the temperature of the raw material was approximately 95°C and the water content was 12 to 15% by mass. Subsequently, the kneaded product was briquetted in a double-roll briquetting machine, including a 44 mm x 44 mm x 13 mm can (one side), under the condition of a 2 mm roll clearance; consequently, Masec-type briquettes were produced. The briquettes had a density of 1120 kg / m3.
[0033] A coal mixture was prepared by mixing 20 parts by mass of the briquettes produced with 80 parts by mass of coal fines, which were pulverized to adjust the particle size. Regarding the coal fines, the particle size adjustment was carried out by pulverizing them so that all particles had a size of 3 mm or less (all particles could pass through a 3 mm sieve opening). The composition of the coal fines that were mixed with the briquettes is shown in Table 4 below, and the properties of the coals, C1 to C7, that were used as coal fines, are shown in Table 5 below. Table 4 Types of Coal Mixing Ratio (% by mass) C1 20 C2 15 C3 15 C4 10 C5 15 C6 5 C7 20 Petition 870250084130, dated 09 / 18 / 2025, pp. 63 / 91 14 / 35 Table 5 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) C1 2.82 1.00 31.4 C2 2.01 1.01 44.8 C3 2.78 1.20 34.2 C4 2.08 1.44 33.3 C5 3.25 0.80 6.7 C6 4.63 0.77 18.7 C7 1.04 0.99 44.6
[0034] Eight types of briquettes produced with the eight types of non-agglomerating or slightly agglomerating coal (T1 to T8) were each mixed with the coal fines described above to generate eight types of coal mixtures, which were then carbonized. The carbonization of the coal mixture was carried out in a carbonization can in which the coal mixture was loaded so that the apparent density of the coal mixture could be 844 kg / m3. The apparent density is a weighted average apparent density of 20% by mass of briquettes, which had an apparent density of 1120 kg / m3, and 80% by mass of coal fines, which had an apparent density of 775 kg / m3.
[0035] In a state where a 10 kg weight was placed on the coal in the carbonization can, carbonization was carried out for 6 hours in an electric furnace with an internal temperature of 1050°C, and the carbonization can was then removed from the electric furnace and cooled under a nitrogen atmosphere. In this way, various types of coke were produced. The various types of coke were tumbled into a drum according to a tumbling resistance test method specified in JIS K 2151:2004; the drum was rotated 150 times at a rotational speed of 15 rpm. After the rotation, the mass of coke with a particle size of 15 mm or Petition 870250084130, dated 09 / 18 / 2025, pp. 64 / 91 15 / 35 superior was measured, a ratio between the mass and the total mass of the coke tested in the assay was determined, and the ratio was multiplied by 100 to obtain a drum resistance index DI (150 / 15). In the present embodiment, the drum resistance index DI (150 / 15) is the resistance of the coke.
[0036] Table 6 below shows the coke strength of the various types of coke produced by carbonization of the respective coal mixtures. Each coal mixture contained the briquettes and coal fines shown in Table 4, which were mixed in a ratio between the mass of the briquettes and the mass of the coal fines of 20:80. The briquettes were briquetted by mixing the respective types of non-agglomerating or slightly agglomerating coal (T1 to T8), shown in Table 1, with the coal materials in the mixing proportions shown in Table 2. Table 6 Level No. TB1 TB2 TB3 TB4 TB5 TB6 TB7 TB8 Non-agglutinating or slightly agglutinating charcoal T1 T2 T3 T4 T5 T6 T7 T8 DI (150 / 50) (-) 79.0 79.3 79.1 78.9 78.7 79.1 78.5 79.0
[0037] Figure 1 is a graph illustrating the relationship between the log CATMF of non-binding or slightly binding coal included in the briquettes and the coke strength of the coke produced with the coal mixture containing the briquettes mixed with coal fines. In Figure 1, the horizontal axis represents the log CATMF (log [ddpm]) of the non-binding or slightly binding coal, and the vertical axis represents the coke strength DI (150 / 15) (-). (-) indicates that it is dimensionless. Data for MF = 0 ddpm are plotted at the position of log MF = 0 for convenience.
[0038] As indicated in Figure 1, the coke strength remained substantially constant, regardless of CA Petition 870250084130, dated 09 / 18 / 2025, pp. 65 / 91 16 / 35 TMF of non-agglutinating or slightly agglutinating coal. This result confirms that the agglutinating property of non-agglutinating or slightly agglutinating coal does not affect the strength of the coke produced, provided that non-agglutinating or slightly agglutinating coal is mixed with the briquettes.
[0039] Now, the strength of the coke produced by mixing non-binding or slightly binding coal with coal fines and by carbonizing a coal mixture containing the coal fines will be described. The composition of the coal fines is shown in Table 7 below. Table 7 Types of Coal Mixing Ratio (% by mass) Non-agglomerating or slightly agglomerating coal (one of T1 to T8) 20 A1 20 A2 15 A3 15 A4 25 A5 5
[0040] The properties of coals, A1 to A5, which were used as coal fines, in addition to non-agglomerating or slightly agglomerating coal, are shown in Table 8 below. Table 8 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) A1 2.05 0.58 29.8 A2 0.95 1.34 43.3 A3 1.75 1.00 48.0 A4 2.80 1.02 34.0 A5 4.34 0.82 15.6
[0041] For particle size adjustment, each of the coals was pulverized so that all particles had a Petition 870250084130, dated 09 / 18 / 2025, page 66 / 91 17 / 35 size of 3 mm or less (all particles could pass through a 3 mm sieve opening). Several types of coke were produced as follows. Eight types of coal mixtures containing the respective types of non-agglutinating or slightly agglutinating coal (T1 to T8) in a quantity of 20% by mass were prepared and each was loaded into a carbonization can so that its apparent density could be 775 kg / m3. Then, carbonization was carried out under the same conditions as those of the carbonization of the coal mixtures described above containing briquettes. Table 9 below shows the coke strength of the various types of coke produced. Table 9 Level No. TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8 Non-agglutinating or slightly agglutinating coal T1 T2 T3 T4 T5 T6 T7 T8 DI (150 / 50) (-) 77.7 72.6 70.5 65.3 66.0 74.8 75.4 73.3
[0042] Figure 2 is a graph illustrating the relationship between the log CATMF of non-binding or slightly binding coal included in coal fines and the coke strength of the coke produced with the coal fines. In Figure 2, the horizontal axis represents the log CATMF (log [ddpm]) of non-binding or slightly binding coal, and the vertical axis represents the coke strength DI (150 / 15) (-). Data for MF = 0 ddpm are plotted at the position of log MF = 0 for convenience.
[0043] As illustrated in Figure 2, in the case where non-binding or slightly binding coal was mixed with coal fines, a correlation between the CATMF of the non-binding or slightly binding coal and the coke strength was observed; that is, the lower the CATMF of the non-binding or slightly binding coal, the lower the coke strength. Figure 1 and Figure 2 in Petition 870250084130, dated 09 / 18 / 2025, pp. 67 / 91 18 / 35 indicate that the various types of coke produced with briquettes containing the respective types of non-binding or slightly binding coal (T1 to T8) showed a difference in coke strength of 0.1, while the various types of coke produced with coal fines containing the same respective types of non-binding or slightly binding coal (T1 to T8) showed an increased difference in coke strength of 12.4. The difference in coke strength is a difference in strength between the coke with the highest strength and the coke with the lowest strength, in the same graph.
[0044] In the case where non-binding or slightly binding coal was included in briquettes, the ratio of non-binding or slightly binding coal in the coal mixture was 4% by mass (the 20% mass mixing ratio of non-binding or slightly binding coal in the briquettes χ the 20% mass mixing ratio of the briquettes in the coal mixture). Consequently, it can be assumed that, in the case where 20% by mass of non-binding or slightly binding coal is mixed with coal fines, the resistance reduction effect is approximately five times greater than in the case where non-binding or slightly binding coal is mixed with briquettes. Even taking this into account, the reduction in coke resistance in the case where non-binding or slightly binding coal was mixed with briquettes was significantly small.These results confirm that, in the case where non-binding or slightly binding coal is mixed with coal fines, the coke strength decreases significantly if the coal includes non-binding or slightly binding coal with a low CATMF, whereas, in the case where the same non-binding or slightly binding coal is included in briquettes, the coke strength does not decrease substantially. Petition 870250084130, dated 09 / 18 / 2025, pp. 68 / 91 19 / 35
[0045] The fact that the influence of non-binding or slightly binding coal on coke strength differs depending on whether it is used in briquettes or directly as coal fines is a finding that was first revealed by conducting the coke production trial in which various types of non-binding or slightly binding coal with different CATMFs were used in briquettes and the coke production trial in which they were used directly as coal fines. It can be inferred from the Patent Literature 1 that adding coal with low CATMF to coal fines can reduce coke strength. However, the fact that the use of non-binding or slightly binding coal in briquettes prevents the coke strength of the coke produced from being affected by the CATMF of the non-binding or slightly binding coal is a finding that was first revealed by the coke production trials.
[0046] Now, the influence on coke strength associated with briquette pulverization will be described. In a method for producing coke that involves mixing briquettes with coal fines and carbonizing the mixture, if non-binding or slightly binding coal is used as coal fines, the coke strength may decrease, and therefore the finding that using non-binding or slightly binding coal in briquettes prevents the decrease in coke strength has important significance for actual operation. This is because, in actual operation, briquettes inevitably become pulverized to some extent in the transport and handling process. Consequently, among the briquettes, in the case of briquettes that have low strength and tend to become pulverized, the pulverization of the briquettes results in the release of coal fines from the non-binding or slightly binding coal.If the CATMF of the coal fines is non-agglomerating or slightly clumping. Petition 870250084130, dated 09 / 18 / 2025, pp. 69 / 91 20 / 35 The amount of binder released is low, and coke production involves the use of a coal mixture containing non-binding or slightly binding coal fines with a low CATMF, therefore there is concern that the strength of the coke produced may be significantly reduced. Until now, it was believed that briquette pulverization has a negative influence on coke strength and that, therefore, briquettes with higher strengths are preferable. However, it is unknown whether the influence of pulverization varies depending on the CATMF of the non-binding or slightly binding coal used.
[0047] That is, it is believed that one of the reasons for the difficulty in estimating coke strength in the case where briquettes containing non-binding or slightly binding coal were used was the failure to correctly understand that the decrease in coke strength due to pulverization of the briquettes varies depending on the CATMF of the non-binding or slightly binding coal. Consequently, the inventors investigated the degree to which coke strength decreases if pulverization of briquettes containing non-binding or slightly binding coal occurs.
[0048] First, several types of briquettes containing non-binding or slightly binding coal with different respective CATMFs were prepared, and the various types of briquettes were pulverized by applying an impact to them. Then broken briquettes were prepared. The briquettes were produced in the following procedure. First, the coal materials were mixed in a mixing ratio shown in Table 10 below. The coal materials included non-binding or slightly binding coal, which was one of T1, T5, and T8, shown in Table 1, and used in an amount of 20% by mass, and also included O17 to O20 coals and pitch (TARP), which was used as a binding agent. To this fo Petition 870250084130, dated 09 / 18 / 2025, pp. 70-91 21 / 35 ram added binders, which were 0.5% by mass of soft pitch (SOP) and 6% by mass of tar (tar slurry) containing solid fines collected from a tar decanter. The resulting mixture was kneaded for 1.5 minutes while being heated with steam injection. The kneaded product was briquetted in a double-roll briquetting machine, including a 44 mm x 44 mm x 13 mm can (one side), under the condition of a 2 mm roll clearance; therefore, Masec-type briquettes were produced. The composition of the briquettes is shown in Table 10 below, and the properties of the coals, O17 to O20, which were used in the production of the briquettes, are shown in Table 11 below. Table 10 Types of Coal Mixing Ratio (% by mass) One of T1, T5 and T8 20 O17 40 O18 14 O19 14 O20 8 TARP 4 Table 11 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) O17 1.86 0.73 20.4 O18 0.95 1.34 43.3 O19 1.83 1.00 46.5 O20 2.80 1.02 34.0
[0049] The three types of briquettes that were produced were pulverized by applying an impact to the briquettes. The pulverization was carried out by loading the briquettes into a cylindrical drum and rotating the drum, thus applying an impact to the briquettes. For each type of briquette, two classes of briquette samples with different pulverization ratios were prepared. Petition 870250084130, dated 09 / 18 / 2025, pp. 71 / 91 22 / 35 and the drum rotation time. 13% by mass of the briquettes prepared in this way (a mixture of the unpulverized portion of the briquettes that remained and the powder resulting from pulverization) were mixed with 87% by mass of coal fines, which were prepared separately. The result was carbonized to investigate the influence of briquette pulverization on coke strength. The conditions for carbonization were the same as in the coke production test described above; the coal mixtures were each loaded into a carbonization can so that their apparent density could be 775 kg / m3, the apparent density being that of a combination of the coal fines and the powder resulting from the pulverization of the briquettes. Then, carbonization was carried out to produce coke. The composition of the coal fines, C21 to C27, that were mixed with the briquettes (or pulverized briquettes) is shown in Table 12 below.Furthermore, the properties of the coals, C21 to C27, which were used as coal fines, are shown in Table 13 below. Table 12 Types of Coal Mixing Ratio (% by mass) C21 24 C22 10 C23 15 C24 8 C25 15 C26 3 C27 25 Table 13 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) C21 2.68 0.984 35.2 C22 2.41 1.053 27.7 Petition 870250084130, dated 09 / 18 / 2025, pp. 72 / 91 23 / 35 Coal Types Log MF (log [ddpm]) Ro (%) TI (% by volume) C23 2.72 1.208 32.7 C24 0.85 1.381 36.5 C25 3.14 0.820 10.0 C26 3.95 0.857 14.8 C27 1.79 0.976 37.1
[0050] With regard to each of the three types of briquettes containing the respective types of non-binding or slightly binding coal T1, T5 and T8, the coke strength of the coke that was produced without pulverization and the coke that was produced at two respective levels of pulverization proportions is shown in Table 14. Table 14 Non-agglomerating or slightly agglomerating coal T8 T8 T8 T1 T1 T1 T5 T5 T5 Briquette pulverization ratio (% by mass) 0.0 21.7 39.7 0.0 24.0 40.2 0.0 32.0 46.2 DI (150 / 50) (-) 78.5 78.4 78.4 78.4 78.3 78.2 78.4 77.8 77.4
[0051] The pulverization ratio (% by mass) of the briquettes is the value calculated from equation (2), shown below. A pulverization ratio of 0.0% by mass indicates a test level in which carbonization was carried out without pulverization. Spray ratio = (mass of powder formed) χ 100 / (mass of briquettes loaded into the test apparatus) (2)
[0052] Figure 3 is a graph illustrating the relationship between the pulverization ratio of the briquettes and the coke strength of the coke produced by mixing the briquettes with coal fines. In Figure 3, the horizontal axis represents the pulverization ratio (% by mass) of the Petition 870250084130, dated 09 / 18 / 2025, pp. 73 / 91 24 / 35 briquettes, and the vertical axis represents the coke resistance (DI) (150 / 15) (-).
[0053] As illustrated in Figure 3, for all three types of non-binding or slightly binding coal, as the pulverization ratio of the briquettes increased, the coke strength decreased; however, the amount of reduction in coke strength varied depending on the types of the three types of non-binding or slightly binding coal. The amount of reduction in coke strength per 1% by mass of the pulverization ratio was calculated from the slope of a regression line for each of the non-binding or slightly binding coal grades, and the results are shown in Table 15 below. Table 15 also shows the results of the log CATMF measurement of the non-binding or slightly binding coal shown in Table 1. Table 15 Non-binding or slightly binding coal. Amount of reduction in coke strength (-) Log CATMF (log [ddpm]) T8 -0.0021 3.32 T1 -0.0049 3.80 T5 -0.0212 0.95
[0054] Figure 4 is a graph illustrating the relationship between the log CATMF of non-binding or slightly binding coal mixed in briquettes and the amount of reduction in coke strength per 1% mass of pulverization. In Figure 4, the horizontal axis represents the log CATMF (log [ddpm]) and the vertical axis represents the amount of reduction in coke strength (-).
[0055] As illustrated in Figure 4, in the case of non-agglutinating or slightly agglutinating coals T1 and T8, which exhibited a log CATMF greater than 3.0, the coke strength did not decrease substantially, even if the briquettes became pulverized. In contrast, in the case of non-agglutinating or slightly agglutinating coal Petition 870250084130, dated 09 / 18 / 2025, pp. 74 / 91 25 / 35 binder T5, which exhibited a log CATMF of 3.0 or less, the coke strength decreased in cases where the briquettes became pulverized. From these results, it can be concluded that non-binding or slightly binding coal with a log CATMF greater than 3.0 is a non-binding or slightly binding coal that does not decrease the coke strength, even if the briquettes become pulverized. As the results in Figure 2 indicate a linear correlation between coke strength and the log CATMF of non-binding or slightly binding coal, it is assumed that there is also a linear correlation between the amount of reduction in coke strength, illustrated in Figure 4, and the log CATMF. In other words, it can be concluded that non-binding or slightly binding coal with a log CATMF of 3.0 or less is a non-binding or slightly binding coal that reduces the strength of the coke if the briquettes become powder.
[0056] Although the degree of pulverization of the briquettes varies depending on the briquette strength, it is difficult to completely avoid pulverization of the briquettes produced. Consequently, in cases where non-binding or slightly binding coal, with a log CATMF of 3.0 or less, is mixed with the briquettes, it is preferable that the briquette strength be increased to inhibit pulverization. The briquette strength can be increased, for example, by increasing the amount of binder that is added to the briquettes or by replacing the binder with another with high binding strength.
[0057] The non-agglutinating or slightly agglutinating coal that is preferably used in the method for estimating the coke strength of the present embodiment is coal with a Gieseler fluidity of 0 ddpm, in which fluidity is not observed in a typical measurement method. Note that some types of coal with a log CATMF of 3.0 or less have a maximum Gieseler fluidity MF, as defined Petition 870250084130, dated 09 / 18 / 2025, pp. 75-91 26 / 35 in JIS M 8801:2008, greater than 0 ddpm. Furthermore, from Figure 4, it can be inferred that, in the case of coal with log CATMF greater than 4.0, substantial reductions in coke strength due to briquette pulverization do not occur. Consequently, non-agglutinating or slightly agglutinating coal, which is preferentially used in the method for estimating coke strength in the present embodiment, can be defined as coal with log CATMF of 4.0 or less. For a simpler definition, it is also possible to define, using the correlation between CATMF and Gieseler maximum flowability, non-agglutinating or slightly agglutinating coal as coal with a Gieseler maximum flowability MF, as defined in JIS M 8801:2008, of 20 ddpm or less.
[0058] The use of the above-described discovery made by the inventors makes it possible to estimate, with greater precision than in methods of the related art, the strength of the coke produced by the carbonization of a coal mixture containing briquettes and coal fines, the briquettes containing non-binding or slightly binding coal mixed with them and being in a partially pulverized state as a result of an impact associated with logistics or similar.
[0059] The method for estimating coke strength in the present embodiment first determines the DIbase coke strength, which is the strength based on the assumption that the briquettes are not pulverized. Coke strength also depends on the properties of the coal, except non-binding or slightly binding coal, in the briquettes and on the properties of the coal fines mixed with the briquettes. Consequently, the estimation of coke strength is performed by first determining the DIbase coke strength, which is the strength based on the assumption that the briquettes are not pulverized, and then subtracting from the resistance Petition 870250084130, dated 09 / 18 / 2025, pp. 76 / 91 27 / 35 coke resistance is the amount of reduction in resistance due to pulverization.
[0060] The DIbase coke strength, which is the strength based on the assumption that the briquettes are not pulverized, can be determined, for example, by a coke production test. Specifically, the coke strength based on the assumption that the briquettes are not pulverized can be determined as follows: the compositions of the briquettes and coal fines expected to be used in a real coke oven are selected, coke is experimentally produced with the compositions, and the coke strength of the coke produced in the test oven is measured. Coke production in a test oven allows for the production of coke without causing the briquettes to pulverize due to handling. In this case, the coke strength in a real oven can be estimated by considering a correlation between the strength of the coke produced in a test oven and the strength of the coke produced in the real oven.Regarding the correlation between the test furnace and the actual furnace, it is preferable that the correlation be investigated beforehand in a test using briquettes that do not contain non-binding or slightly binding coal, which can be a factor that reduces the coke strength. An equation for estimating the coke strength generated by a method known in the art can be used without performing a carbonization test.
[0061] An example of a method for estimating the amount of reduction in coke strength due to briquette pulverization is described below. The reduction in coke strength occurs as a result of the release of non-binding or slightly binding powdered coal in the coal fines due to briquette pulverization. Therefore, it is necessary to first estimate the amount of non-binding or slightly binding coal that is released. Petition 870250084130, dated 09 / 18 / 2025, pp. 77 / 91 28 / 35
[0062] The amount (ratio in the coal mixture) of non-binding or slightly binding coal that is released as a result of briquette pulverization can be calculated by multiplying the briquette mixing ratio by the briquette pulverization ratio and by the ratio of non-binding or slightly binding coal in the briquettes. The briquette pulverization ratio depends on the briquette strength and the impact force applied to the briquettes. In this sense, a dust formation rate resulting from an impact received during the period between briquette production and loading into a coke oven can be used as an index of strength, and in this case, the pulverization ratio and strength have the same meaning.In other words, in this case, the briquette strength can be expressed as the rate of formation (pulverization rate) of the powder formed by an impact received during the period between briquette production and loading into a coke oven. The strength (pulverization rate) can be determined, for example, by a test in which the impact received during the period between briquette production and loading into a coke oven is estimated from a cumulative drop height or similar, and in which the amount of powder formed when the impact is applied to the briquettes is measured. Furthermore, the pulverization rate can be estimated based on a correlation between another strength index and the pulverization rate.
[0063] As mentioned earlier, the strength of the coke decreases if non-binding or slightly binding coal dust formed by pulverizing the briquettes is accidentally introduced into the coal fines. The decrease in coke strength due to an increased mixing ratio of non-binding or slightly binding coal in the coal fines depends on the log CATMF of the non-binding or slightly binding coal, as illustrated. Petition 870250084130, dated 09 / 18 / 2025, pp. 78 / 91 29 / 35 shown in Figure 2. In addition, the decrease also depends on the pulverization ratio (amount of powder formed) of the briquettes, as illustrated in Figure 3.
[0064] The slope of the graph in Figure 2 indicates that, under the condition of a non-binding or slightly binding coal mixing ratio of 20% by mass, a decrease in log CATMF of 1 results in a decrease in coke strength of 3.07. Consequently, the decrease in coke strength per 1% by mass of the non-binding or slightly binding coal mixing ratio in the coal fines is 0.1535, which is determined by dividing 3.07 by 20.
[0065] In the example illustrated in Figure 4, it is assumed that when log CATMF is 4.0 or higher, the decrease in resistance is substantially zero. Consequently, the amount of decrease in coke resistance per 1% by mass of non-binding or slightly binding coal in coal fines due to a decrease in log CATMF of 1 can be calculated from (4.0 - log CATMF) x 0.1535. Thus, it is understood that the coke resistance can be estimated using equation (3), shown below, which is an equation that expresses the method for estimating coke resistance based on the example illustrated in Figure 4. DI (150 / 15) = DIbase - K x (a - log CATMF) x R (3)
[0066] In equation (3), a is a limiting value of a minimum log CATMF at which the coke strength does not decrease even if briquettes containing non-binding or slightly binding coal mixed with it become pulverized. In the example illustrated in Figure 4, a is 4.0. The log CATMF is the common logarithm of the measured CATMF value of non-binding or slightly binding coal and is an example of thermoplasticity (CATP) of a mixture containing the non-binding or slightly binding coal with an amine compound. Petition 870250084130, dated 09 / 18 / 2025, pp. 79 / 91 30 / 35 primary or secondary added to it, the compound having an aromatic ring. K is a constant that expresses the decrease in coke strength per unit of log CATMF and per unit of the amount of non-binding or slightly binding coal included in the coal fines due to briquette pulverization. In the example illustrated in Figure 4, K is 0.1535.
[0067] R is the rate of increase in the amount of non-binding or slightly binding coal included in coal fines due to pulverization of the briquettes. The rate of increase R in the amount of non-binding or slightly binding coal included in coal fines due to pulverization of the briquettes can be determined as follows. The ratio between the amount of powder formed and the total amount of coal mixture can be determined by the mixing ratio Wbq of the briquettes, the mixing ratio Wncc of non-binding or slightly binding coal in the briquettes, and the pulverization ratio that results when an impact comparable to the impact received by the briquettes until they are loaded into the coke oven is applied.Wp = Wbq χ Wncc χ Sbq, where Sbq is the briquette resistance, which is represented by the pulverization ratio resulting from an impact applied to the briquettes until they are loaded into the coke oven, and Wp is the ratio between the amount of powder formed and the total amount of the coal mixture.
[0068] Due to the dust formed, the ratio of coal fines in the coal mixture increases by Wp from the ratio of coal fines before pulverization (1 - Wbq) and, consequently, the rate of increase R in non-agglutinating or slightly agglutinating coal dust present in the coal fines is determined by R = Wp / (1 - Wbq + Wp).
[0069] Thus, the coke strength can be estimated by considering the pulverization of the briquettes, using equation (3), provided that Petition 870250084130, dated 09 / 18 / 2025, pp. 80 / 91 31 / 35 the constant aea constant K is determined beforehand in an experiment or similar, the DIbase is determined in a carbonization test or similar, the CATP thermoplasticity (log CATMF, in the example described above) of non-agglomerating or slightly agglutinating coal is measured, and R is determined from Wbq, Wncc and Sbq.
[0070] As described, the method for estimating the coke strength of the present embodiment is a method for estimating the coke strength that includes estimating, with the five parameters listed below, the coke strength of coke that is produced by carbonizing a mixture of coal containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them and being in a partially pulverized state. 1. Coke strength (DIbase) of coke produced by carbonizing a mixture of different coal containing briquettes and powdered coal, where the briquettes are in a non-pulverized state. 2. Mixing ratio (Wbq) of briquettes mixed in the coal mixture 3. Resistance (Sbq) of the briquettes 4. Mixing ratio (Wncc) of non-binding or slightly binding coal mixed with briquettes 5. Thermoplasticity (CATP) of a mixture containing non-binding or slightly binding charcoal with at least one compound added to it, the at least one compound being selected from primary amine compounds and secondary amine compounds, the primary amine compounds and the secondary amine compounds each having an aromatic ring.
[0071] The use of the five parameters for estimating coke strength allows estimating coke strength considering Petition 870250084130, dated 09 / 18 / 2025, pp. 81 / 91 32 / 35 a decrease in the strength of the coke due to the partial pulverization of the briquettes included in the coal mixture. Consequently, it is possible to estimate, with greater precision than in methods of the related art, the strength of the coke that is produced from a coal mixture containing briquettes and coal powder, the briquettes containing non-binding or slightly binding coal mixed to it.
[0072] Next, an embodiment of a method for producing coke will be described. The method includes estimating the strength of the coke according to the thermoplasticity of the non-binding or slightly binding coal that is mixed with the briquettes and determining the mixing ratio of the non-binding or slightly binding coal that is mixed with the briquettes, based on the estimated strength of the coke, to produce coke.
[0073] The method for producing coke of the present embodiment is implemented as follows. Coal with a maximum Gieseler flowability factor (CATMF), as defined in JIS M 8801:2008, of 20 ddpm or less, is selected as the non-binding or slightly binding coal that is mixed with the briquettes. First, with respect to the selected non-binding or slightly binding coal, 1 part by mass of N,N'-di-2-naphthyl-p-phenylenediamine is added to 10 parts by mass of the non-binding or slightly binding coal, and then the maximum Gieseler flowability factor (CATMF) is measured.
[0074] Next, the types and proportions of coal mixtures other than non-binding or slightly binding coal used in the briquettes, as well as the types and proportions of coal mixtures that constitute the coal fines mixed into the briquettes, are selected, and then the briquettes containing the non-binding or slightly binding coal mixed into them are selected. Petition 870250084130, dated 09 / 18 / 2025, pp. 82-91 33 / 35 selected mixing ratio (Wncc) are produced. Coke is produced by carbonizing a coal mixture in which the briquettes produced, without being pulverized, are mixed with coal fines in the predetermined mixing ratio (Wbq), and then the coking strength (DIbase) of the coke is determined by means of a carbonization test or similar.
[0075] Furthermore, the pulverization ratio, which is a ratio between the briquettes that are pulverizated by an impact during the process, from the moment the briquettes are produced until the moment they are loaded into the coke oven, is determined as the resistance (Sbq) of the briquettes produced; consequently, the coke resistance of the coke that is produced under the conditions can be estimated using equation (3), shown above. In addition, the five parameters are adjusted so that the estimated coke resistance can be equal to or greater than a target coke resistance. For example, if the estimated coke resistance is less than the target coke resistance, the resistance (Sbq) of the briquettes should be increased, for example, by increasing the amount of binder in the briquettes. In this way, the coke resistance of the coke that is produced can be improved. The target coke resistance is an example of a predetermined coke resistance.
[0076] Furthermore, the strength of the coke produced can be adjusted by adjusting the mixing ratio of non-binding or slightly binding coal in the briquettes. If the estimated strength of the coke is greater than the target strength of the coke, the mixing ratio of non-binding or slightly binding coal, which is inexpensive, can be increased, and in that case, the costs associated with coke production can be reduced while maintaining the target strength of the coke. If the estimated strength of the coke is less than the target strength of the coke, the mixing ratio of non-binding coal can be increased. Petition 870250084130, dated 09 / 18 / 2025, pp. 83-91 34 / 35 te or slightly clumping can be reduced.
[0077] If the mixing ratio of the selected non-binding or slightly binding coal in the briquettes is altered, the coke strength (DIbase) of the coke produced by carbonizing the different coal mixture, containing powdered coal and briquettes in a non-pulverized state, may be altered. In this case, a coke production test using a coal mixture with an altered mixing ratio of non-binding or slightly binding coal can be conducted to preliminarily determine a correlation between the coke strength (DIbase) and the mixing ratio (Wncc) of the non-binding or slightly binding coal mixed into the briquettes; consequently, the coke strength can be estimated by considering the changes in coke strength (DIbase).In this way, the target strength of the coal can be met, and the amount of non-agglomerating or slightly agglomerating coal used, which has low agglutinating properties and is of inferior quality, can also be maximized. Consequently, cost reduction can be achieved and the efficient use of coal resources can also be attained.
[0078] Furthermore, it is preferable that the coal mixture be prepared in such a way that the mixing ratio of non-binding or slightly binding coal, with a log CATMF of 3.0 or less, present in the briquettes, is greater than the mixing ratio of non-binding or slightly binding coal, with a log CATMF of 3.0 or less, present in the powdered coal, and that coke is produced by carbonization of the adjusted coal mixture. The log CATMF of non-binding or slightly binding coal is the common logarithm of the Gieseler maximum flowability MF, as defined in JIS M 8801:2008, and is measured after 1 part by mass of N,N'-di-2-naphthyl-p-phenylenediamine is added to 10 parts by mass. Petition 870250084130, dated 09 / 18 / 2025, pp. 84 / 91 35 / 35 mass of non-binding or slightly binding coal.
[0079] As illustrated in Figures 1 and 4, non-binding or slightly binding coal with a log CATMF of 3.0 or less does not decrease the strength of coke if included in briquettes, while such non-binding or slightly binding coal decreases the strength of coke if included in coal fines. Consequently, it is preferable that non-binding or slightly binding coal with a log CATMF of 3.0 or less be mixed in as large a quantity as possible in briquettes, and it is preferable that the mixing ratio of non-binding or slightly binding coal in briquettes be greater than the mixing ratio of this coal in coal fines. In this case, it is possible to produce coke with greater strength.
[0080] The description above describes the estimation of the influence of the properties of non-binding or slightly binding coal and briquette pulverization on resistance reduction, using a linear relationship based on experimental results; alternatively, a non-linear correlation can be used. Furthermore, if necessary, some variables can be determined by approximation, variables with little influence can be omitted, and the form of the equations can be altered.
Claims
1. A method for estimating coke strength, characterized in that it comprises estimating the coke strength of coke produced by carbonizing a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein in the coal mixture that is carbonized to produce the coke, the briquettes are in a partially pulverized state, and the coke strength of the coke is estimated using a coke strength of coke produced by carbonizing a different coal mixture containing briquettes and powdered coal and in which the briquettes are in a non-pulverized state, a mixing ratio of the briquettes mixed in the coal mixture, a strength of the briquettes, a mixing ratio of the non-binding or slightly binding coal mixed with the briquettes,and the thermoplasticity of a mixture containing non-binding or slightly binding charcoal with at least one compound added to it, the at least one compound being selected from primary amine compounds and secondary amine compounds, the primary amine compounds and the secondary amine compounds each having an aromatic ring.
2. A method for producing coke, characterized in that it comprises producing coke by carbonizing a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein the method comprises making an adjustment to prepare the briquettes and / or prepare the coal mixture so that a coke strength equal to or greater than a predetermined coke strength is achieved, the coke strength being estimated by the method for estimating a coke strength as defined in claim 1, the adjustment comprising adjusting at least one of the coke strengths of the coke that is produced by carbonizing a different coal mixture containing the briquettes and powdered coal and in which the briquettes are in a non-pulverized state, the mixing ratio of the briquettes mixed in the coal mixture,The strength of the briquettes, the mixing ratio of the non-binding or slightly binding coal mixed with the briquettes, and the thermoplasticity of the mixture containing the non-binding or slightly binding coal with at least one compound added to it, the at least one compound being selected from primary amine compounds and secondary amine compounds, the primary amine compounds and the secondary amine compounds each having an aromatic ring, and producing coke by carbonization of the prepared coal mixture.
3. Method for producing coke, characterized in that it comprises the production of coke by carbonization of a coal mixture containing briquettes and powdered coal, the briquettes containing non-binding or slightly binding coal mixed with them, wherein the method comprises measuring a maximum Gieseler flowability MF of the coal. Petition 870250084130, dated 09 / 18 / 2025, p.45 / 91 3 / 3 binder or slightly binder after adding 1 part by mass of N,N'-di-2-naphthyl-p-phenylenediamine to 10 parts by mass of non-binding or slightly binder coal, prepare the coal mixture so that a mixing ratio of non-binding or slightly binder coal having a common logarithm of the maximum Gieseler flow rate measured MF of 3.0 or less that is present in the briquettes is greater than a mixing ratio of non-binding or slightly binder coal having a common logarithm of the maximum Gieseler flow rate measured MF of 3.0 or less that is present in the powdered coal, and produce coke by carbonization of the prepared coal mixture.