Method for evaluating binder and method for producing coke

Abstract

To provide a caking agent evaluation method which suitably and simply evaluates an expansibility increasing effect of a caking agent, and a coke production method.SOLUTION: According to an aspect of the present invention, there is provided a caking agent evaluation method which comprises: a glass transition point acquisition step of acquiring a glass transition point of a mixture of a coal material as a raw material of coke and a caking agent mixed with the coal material for a plurality of types of the caking agent; and an evaluation step of evaluating an expansibility increasing effect of each caking agent for the coal material on the basis of the glass transition point of the mixture obtained for each caking agent.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a method for evaluating a binder and a method for producing coke. [Background technology]

[0002] Coke is produced, for example, by carbonizing coal materials, which are the raw materials for coke, in a coke oven. The coal materials charged into the coke oven may be of a single type, or may be a blend of multiple types of coal materials. When the coal materials charged into the coke oven are heated to a certain temperature range (for example, about 300 to 550°C), they soften and melt, and then foam and expand as volatile matter is generated. This foaming and expansion causes the individual coal particles to bond together (in other words, the voids between the coal particles are blocked), forming a lump of semi-coke. The semi-coke is further heated to around 1000°C to be sintered and become a robust coke.

[0003] Here, in the process of producing semi-coke, the lower the thermoplastic temperature of the coal material, the more coal particles will thermoplasticize and melt, and the more coal particles will foam and expand. As a result, more voids will be blocked, and stronger coke will be produced.

[0004] Therefore, in order to lower the softening and melting temperature of the coal material, a mixture (blended coal) in which a binder is blended (mixed) with the coal material may be charged into the coke oven. Examples of the binder include tar pitch, petroleum pitch, solvent refined coal, and solvent extracted coal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-199791 A [Patent Document 2] JP 2012-72390 A [Patent Document 3] International Publication No. 2011 / 004495 [Non-patent literature]

[0006] [Non-Patent Document 1] Shinohara et al., "Evaluation of coal swelling by adding organic compounds using molecular dynamics simulation," Abstracts of the 56th Coal Science Conference, 2-10 [Non-Patent Document 2] Hata et al., "Construction of a molecular structure model of coal," Abstracts of the 28th Japan Society of Energy, 1-4-1 Summary of the Invention [Problem to be solved by the invention]

[0007] One of the properties required for a binder is the expansion improvement effect, which allows more coal particles to foam and expand. A binder with a high expansion improvement effect can foam and expand more coal particles by lowering the softening and melting temperature of the coal material. Here, there is compatibility between binders and coal materials, and just because binder A has a high expansion improvement effect on a certain coal material A, it does not necessarily mean that the same binder A will also have a high expansion improvement effect on another coal material B.

[0008] For this reason, there has been a strong demand for a method for appropriately and simply evaluating the expansion improvement effect of a binder, but no such method has been proposed so far. For example, Patent Documents 1-3 and Non-Patent Documents 1-2 disclose techniques related to the production of coke. In summary, Patent Document 1 discloses a technique for blending caking coal and non-slightly caking coal. Patent Document 2 discloses a technique for evaluating the thermoplasticity (expansion improvement effect) of a binder in a state simulating the surrounding environment of a coal material and a binder that have been thermoplasticized in a coke oven. Patent Document 3 discloses a binder that includes a matrix phase containing an aromatic compound having a hydrogen-donating naphthene group and carbon particles dispersed in the matrix phase.

[0009] Non-Patent Document 1 discloses that there is a positive correlation between the calculated density of blended coal and the maximum expansion ratio of blended coal in blended coal with different types of binders. Non-Patent Document 2 discloses a three-dimensional molecular aggregation model that can qualitatively represent the thermal relaxation behavior for two types of coal.

[0010] However, in any of the technologies, the expansion improvement effect of the binder could not be appropriately evaluated. Patent Documents 1 and 3, and Non-Patent Document 2 do not mention the expansion improvement effect of the binder. Patent Document 2 evaluates the expansion improvement effect of the binder using the parameter of penetration distance, but to calculate the penetration distance, it is necessary to measure the Gieseler maximum fluidity, which is very time-consuming. Non-Patent Document 1 discloses that there is a positive correlation between the calculated density of blended coal and the maximum expansion ratio of blended coal, but such a correlation does not exist for all binders.

[0011] In addition, as evaluation methods other than the above, methods such as measuring the fluidity of blended coal with a Gieseler plastometer and measuring the expansion ratio of blended coal with a dilatometer are known, but all of them are very time-consuming.

[0012] Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an evaluation method for a binder and a method for producing coke that can appropriately and simply evaluate the expansion improvement effect of the binder.

Means for Solving the Problems

[0013] In order to solve the above problems, according to one aspect of the present invention, a glass transition point acquisition step of obtaining the glass transition point of a coal material that is a raw material for coke, and further obtaining the glass transition points of mixtures of the coal material and binders mixed with the coal material for a plurality of types of binders, and an evaluation step of evaluating the expansion improvement effect of each binder with respect to the coal material based on the glass transition point of the coal material and the glass transition points of the mixtures obtained for each binder are provided, and an evaluation method for a binder is provided, characterized by including these steps.

[0014] According to another aspect of the present invention, there is provided a method for evaluating a binder, including a glass transition point acquisition step of obtaining the glass transition point of a coal material as a raw material for coke, and further obtaining the glass transition point of a mixture of the coal material and a binder mixed with the coal material, and an evaluation step of evaluating the expansion improvement effect of the binder on the coal material based on the glass transition point of the coal material and the glass transition point of the mixture.

[0015] Here, in the evaluation step, it may be evaluated that the smaller the glass transition point obtained for each binder is with respect to the glass transition point of the coal material, the greater the expansion improvement effect of the binder.

[0016] Also, when the glass transition point obtained for each binder is 15 °C or more lower than the glass transition point of the coal material, it may be evaluated that the expansion improvement effect of the binder is great.

[0017] Here, in the glass transition point acquisition step, a molecular model of the coal material may be constructed by modeling the molecules constituting the coal material, and further a molecular model of the binder may be constructed by modeling the molecules constituting the binder. The specific volume of the mixed model of the molecular model of the coal material and the molecular model of the binder may be obtained at a plurality of temperatures by the molecular dynamics calculation method, and the glass transition point of the mixture may be obtained based on the correlation graph between the specific volume of the mixed model and the temperature.

[0018] Also, in the glass transition point acquisition step, a molecular model of the coal material may be constructed by modeling the molecules constituting the coal material, the specific volume of the molecular model of the coal material may be obtained at a plurality of temperatures by the molecular dynamics calculation method, and the glass transition point of the coal material may be obtained based on the correlation graph between the specific volume of the molecular model of the coal material and the temperature.

[0019] Also, the coal material may be strongly caking coal or non-finely caking coal.

[0020] According to another aspect of the present invention, there is provided a method for producing coke, characterized in that a binder to be added to a coal material is determined based on the above-described method for evaluating the binder, and coke is produced using the determined binder and the coal material.

Advantages of the Invention

[0021] According to the above aspect of the present invention, the effect of improving the expansibility of the binder can be appropriately and easily evaluated.

Brief Description of the Drawings

[0022]

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Embodiments for Carrying Out the Invention

[0023] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The present inventor has intensively studied an evaluation method for binders that appropriately and simply evaluates the expansion - property improvement effect of binders. The present inventor focused on the glass transition point of a mixture of a coal material used as a raw material for coke and a binder mixed with the coal material. As a result, the present inventor found that the expansion - property improvement effect of the binder can be evaluated by comparing the glass transition point of the mixture with the glass transition point of the coal material. Generally speaking, when the glass transition point of the mixture is lower than the glass transition point of the coal material, the expansion - property improvement effect of the binder contained in the mixture is high. Hereinafter, this embodiment will be described in detail.

[0024] <1. Outline of the Evaluation Method> First, an overview of the method for evaluating the binder according to this embodiment will be described. The method for evaluating the binder according to this embodiment includes a glass transition point acquisition step and an evaluation step. In the glass transition point acquisition step, the glass transition points of mixtures of coal materials that are raw materials for coke and binders mixed with the coal materials are obtained for a plurality of types of binders. In the evaluation step, based on the glass transition points of the mixtures obtained for each binder, the expansion property improvement effect of each binder on the coal material is evaluated. Note that the expansion property improvement effect in this embodiment is evaluated, for example, by the maximum expansion rate defined in JIS M 8801 2008. The greater the maximum expansion rate, the greater the expansion property improvement effect. In this embodiment, the expansion property improvement effect can be evaluated without performing the test according to JIS M 8813. Hereinafter, each step will be described in detail.

[0025] <1-1. Glass transition point acquisition step> As described above, in the glass transition point acquisition step, the glass transition points of mixtures of coal materials that are raw materials for coke and binders mixed with the coal materials are obtained for a plurality of types of binders. Here, the coal materials and binders targeted by the method for evaluating the binder according to this embodiment are not particularly limited, and all those that can be used in the production of coke or those that may be used in the future are included.

[0026] For example, the coal materials according to this embodiment include all coals referred to as raw coals. Raw coal is coal that is a raw material for coke, and examples include caking coal (such as pitch coal), non-caking coal, and the like. The coal material may be a single type, or may be a blended coal obtained by mixing (blending) a plurality of types of coal materials with different origins, for example.

[0027] The type of binder is not particularly limited either. Examples of the binder include tar pitch, petroleum pitch, solvent-refined coal, solvent-extracted coal, and the like. A binder composed of a single type of carbon material (such as coronene, corannulene, etc.) may be used. Such a carbon material may be obtained, for example, by performing the above-described solvent extraction or the like on existing tar pitch or the like, or may be newly synthesized.

[0028] As specific methods for obtaining the glass transition point, there are methods such as obtaining the glass transition point by modeling coal materials and binders, and methods for measuring the glass transition point using DSC (differential scanning calorimetry). Here, a method for obtaining the glass transition point by modeling coal materials and binders (hereinafter also referred to as the "modeling acquisition method") will be described in detail.

[0029] Here, the merits of the modeling acquisition method and, further, the reasons why the inventor focused on the glass transition point as an index for evaluating the expansion improvement effect will be explained.

[0030] Coal materials, whether they are single types or blended coals of multiple types, are often composed of multiple types of molecules with significantly different molecular weights. The inventor believes that among these molecules, relatively low-molecular-weight molecules soften and melt from low temperatures, and by expanding the softening and melting region while dissolving components with large molecular weights one after another, the expansibility is exhibited. Therefore, it is considered that softening and melting are promoted and the expansibility is improved by the softening and melting starting at a lower temperature. Accordingly, it was considered that softening and melting are promoted and the expansibility is improved when the glass transition temperature, which is the temperature at which the aggregated structure of coal molecules relaxes, occurs at a low temperature.

[0031] As described above, when the coal material charged into the coke oven is heated to a certain temperature range (for example, about 300 to 550 °C), it softens and melts, and then foams and expands as the volatile matter is generated. Due to such foaming and expansion, each coal particle binds to each other, and voids between coal particles are blocked, and a strong coke is produced. Therefore, how much coal material can be softened and melted is important for increasing the strength of the coke. Here, the softening and melting of the coal material occurs when the interaction between the molecules constituting the coal material (the interaction of attracting each other. For example, van der Waals force (intermolecular force), electrostatic interaction) weakens and the molecules can move freely with respect to each other.

[0032] As will be described later, in the modeling measurement method, a molecular model of the coal material is constructed by modeling the molecules that make up the coal material. Roughly speaking, by extracting a plurality of types of molecules from the coal material by extracting the coal material with a plurality of types of solvents, the molecules in each solvent are modeled. Then, a molecular model of the coal material is constructed by mixing each molecular model according to their mass ratios. At this time, the molecular model of low molecular weight is always included in the molecular model of the coal material. And in the modeling measurement method, the glass transition point of the coal material (or a mixture of the coal material and the binder) is obtained in consideration of the molecular model of low molecular weight. Furthermore, the lower the glass transition point, the weaker the interaction between the molecules constituting the coal material becomes at a lower temperature. Therefore, it is considered that the softening and melting of the coal material starts at a lower temperature and stronger coke is produced. For this reason, the present inventor focused on the glass transition point.

[0033] On the other hand, in the method of measuring the glass transition point using DSC (differential scanning calorimetry), the glass transition point of the coal material (or a mixture of the coal material and the binder mixed at a desired mixing ratio) is directly measured. However, in DSC measurement, the endothermic peak due to gas generation may overlap with the endothermic peak due to thermal expansion, and it may be difficult to calculate the glass transition point.

[0034] In the modeling measurement method, a molecular model of the coal material is constructed by modeling the components that make up the coal material. Hereinafter, the specific content of the modeling measurement method will be described based on FIGS. 12 and 13. FIG. 12 is a conceptual diagram, and FIG. 13 is a flowchart. Specifically, first, a coal material is prepared. The coal material is preferably pulverized sufficiently in advance. This is to easily dissolve the soluble components of each solvent in each solvent. Next, a plurality of types of components are extracted from the coal material by extracting the coal material with a plurality of types of solvents.

[0035] First, in step S10, the coal material is put into the first solvent 100. Here, as the first solvent 100, for example, a solvent obtained by mixing NMP (N-methyl-2-pyrrolidone) and carbon disulfide in a volume ratio of 50:50 (hereinafter, also referred to as "magic solvent"), etc. can be mentioned. Then, by sufficiently stirring the first solvent 100 into which the coal material has been put, the coal material is fractionated into a first component (a component dissolved in the magic solvent. Hereinafter, also referred to as "MS") and a fifth component which is an extraction residue (a component not dissolved in the first solvent 100. Hereinafter, also referred to as "MI"). Then, the first component MS is extracted from the first solvent 100, and the fifth component MI is separated from the first solvent 100 by filtration or the like, washed, and dried.

[0036] Next, in step S20, the first component MS is put into the second solvent 110. Here, as the second solvent 110, for example, acetone, toluene, chloroform, etc. can be mentioned. These solvents may be used alone, or any one or more of them may be mixed and used. Then, by sufficiently stirring the second solvent 110 into which the first component MS has been put, the first component MS is fractionated into a second component (a component dissolved in the second solvent 110. Hereinafter, also referred to as "AS") and an extraction residue (a component not dissolved in the second solvent 110. Hereinafter, also referred to as "AI"). Then, the extraction residue AI is separated from the second solvent 110 by filtration or the like, washed, and dried.

[0037] Next, in step S30, the extraction residue AI is put into the third solvent 120. Here, examples of the third solvent 120 include pyridine, ethylenediamine, tetrahydrofuran, and the like. These solvents may be used alone, or any one or more of them may be mixed and used. Next, by sufficiently stirring the third solvent 120 into which the extraction residue AI has been put, the extraction residue AI is fractionated into a third component (a component dissolved in the third solvent 120. Hereinafter, also referred to as "PS") and a fourth component that is the extraction residue (a component not dissolved in the third solvent 120. Hereinafter, also referred to as "PI"). Next, the third component PS is extracted from the third solvent 120, and the fourth component PI is separated from the third solvent 120 by filtration or the like, and washed and dried.

[0038] Through the above steps, the coal material is fractionated into four components, namely the second to fifth components AS, PS, PI, and MI. The first component MS described above will be composed of the second to fourth components AS, PS, and PI. In the above example, fractionation is performed with the first to third solvents (for example, magic solvent, acetone, and pyridine) 100 to 120, but the types and numbers of solvents used are not limited to these examples. For example, the more types of solvents used, the more components the coal material can be fractionated into, so an improvement in the measurement accuracy of the glass transition point described later can be expected. However, the more solvents used, the more fractionation steps increase, so it is preferably about three types as described above.

[0039] Next, elemental analysis of the second to fifth components AS, PS, PI, and MI, 1 1H NMR measurement, 13By performing \(^{13}\)C NMR measurement and further GPC (Gel Permeation Chromatography) measurement, the constituent elements, molecular structures, and molecular weights (at least one of the weight-average molecular weight and the number-average molecular weight) of the second to fifth components AS, PS, PI, and MI are specified. Here, the elemental analysis of the second to fifth components AS, PS, PI, and MI can be performed in accordance with JIS M 8813 or JIS M 8819. Next, an average molecular structure (i.e., a molecular model) of the second to fifth components AS, PS, PI, and MI is constructed so as to conform to the respective analysis values. Examples of the average molecular structures of the second to fifth components AS, PS, PI, and MI are shown in FIGS. 1 to 4. Here, the average molecular structure is a molecular structure that satisfies the molecular weight, the specified carbon skeleton structure, functional groups, and elemental analysis values of each fraction component. Although the presence of a compound having the average molecular structure in coal is not necessarily indicated, it is considered to be a molecular structure that reflects the physical properties of the fraction components.

[0040] What should be noted here is that the structures shown in FIGS. 1 to 4 are merely the average molecular structures of the second to fifth components AS, PS, PI, and MI. That is, the second to fifth components AS, PS, PI, and MI do not necessarily contain the compounds having the average molecular structures shown in FIGS. 1 to 4. For example, although the average molecular structure shown in FIG. 1 has a structure in which two polycyclic aromatic hydrocarbons are connected by a chain aliphatic hydrocarbon, the second component AS does not necessarily have the average molecular structure shown in FIG. 1. For example, the second component AS may be composed of a single polycyclic aromatic hydrocarbon or may be an aggregate of a plurality of types of polycyclic aromatic hydrocarbons. An example of their average structure is shown in FIG. 1. That is, in the present embodiment, various possibilities are considered as the structure of the second component AS, but in order to simplify the molecular dynamics calculation, it is assumed that it has one type of average molecular structure. The same applies to the other third to fifth components PS, PI, and MI.

[0041] Next, based on the mass ratios and molecular weights of the second to fifth components AS, PS, PI, and MI, the molecular number ratio (unit molecular number ratio) of the second to fifth components AS, PS, PI, and MI is determined. As an example, when the second to fifth components AS, PS, PI, and MI have the average molecular structures shown in FIGS. 1 to 4, and their mass ratios are 4.2:13.8:18.5:65.4 (note that the total slightly exceeds 100, which is due to reasons such as a very small amount of solvent remaining. In any case, it does not affect the subsequent calculations.), the unit molecular number ratio of the second to fifth components AS, PS, PI, and MI is 1:1:2:3. Next, based on these data, a molecular model of the coal material is constructed. The molecular model of the coal material has the second to fifth components AS, PS, PI, and MI, and the second to fifth components AS, PS, PI, and MI have the average molecular structures described above. Further, the molecular model of the coal material has the second to fifth components AS, PS, PI, and MI in the unit molecular number ratio described above.

[0042] Next, the molecules constituting the binder are modeled. Here, in order to simplify the molecular dynamics calculation and facilitate the selection of an appropriate binder, the binder is assumed to be composed of a single component (for example, coronene or corannulene). Therefore, the molecular structure of the component constituting the binder may be directly used as the average molecular structure (molecular model). FIG. 5(a) shows the molecular model of coronene, and (b) shows the molecular model of corannulene. The upper figure is a plan view, and the lower figure shows a side view. Coronene has a substantially planar structure, while corannulene has a slightly three-dimensional structure.

[0043] However, the binder actually used may be composed of multiple types of components such as tar pitch, petroleum pitch, etc. In this case, the molecular structure and mass ratio of the components constituting the binder can be identified by known methods (for example, Gas Chromatography-Mass Spectrometry (GC-MS) or Field Desorption-Mass Spectrometry (FD-MS), which are a kind of mass spectrometry), and the swelling improvement effect can be evaluated for each component by the evaluation method described later. Then, a binder containing a large amount (for example, 50% by mass or more) of components with a high swelling improvement effect may be selected. Alternatively, the binder may be modeled in the same way as the method for modeling coal materials. For example, the binder may be fractionated into multiple types of components using the above-described first to third solvents 100 to 120, and the average molecular structure and unit molecule number ratio of each component may be determined. The molecular model of the binder obtained in this way has multiple components, and each component has an average molecular structure. Furthermore, the molecular model of the binder has each component in terms of the unit molecule number ratio.

[0044] Next, a mixed model of the molecular model of the coal material and the molecular model of the binder is constructed. The binder is often added to the coal material at about 2 to 10% by mass. Considering this point, the unit molecule number ratio of each component constituting the mixed model is calculated. Each component (the component of the coal material and the component of the binder) constituting the mixed model has the above-described average molecular structure. As an example, the mixed model contains the second to fifth components AS, PS, PI, and MI and coronene or corannulene as the binder in a unit molecule number ratio of 1:1:2:3:1. In this case, coronene or corannulene is added to the coal material at a ratio of approximately 5.0% by mass with respect to the coal material. In the following description, the mixed model of the molecular model of the coal material and coronene is also referred to as mixed model A, and the mixed model of the molecular model of the coal material and corannulene is also referred to as mixed model B.

[0045] Next, perform molecular dynamics calculations on the hybrid model to obtain the specific volume of the hybrid model. The software used for the molecular dynamics calculations is not particularly limited, and examples include MaterialStudio manufactured by Daikin Industries, Ltd. The COMPASSII force field is used for the molecular dynamics calculations, and the molecular dynamics calculations are performed at predetermined time intervals (for example, at 1 fs intervals) for a predetermined number of steps (for example, 5,000,000 steps (= 5 ns)) under the NPT ensemble. This process is performed at predetermined temperature intervals (for example, at 50 °C intervals within the range of 0 to 600 °C) within a predetermined temperature range to obtain the specific volume at each temperature. Here, the temperature of the hybrid model is assumed to be the temperature of the mixture of the coal material and the binder. Note that the predetermined temperature range and the predetermined temperature interval are not limited to the above examples, of course. For example, if the glass transition point described later is not found within the range of 0 to 600 °C, it is preferable to expand the predetermined temperature range.

[0046] The following shows a specific method of the calculation method. First, randomly arrange the unit cells of the hybrid model in a three-dimensional space. Here, the unit cell of the hybrid model may include each component (the component of the coal material and the component of the binder) constituting the hybrid model in the minimum number of the above unit molecule ratios. For example, when the hybrid model includes the 2nd to 5th components AS, PS, PI, and MI and coronene or corannulene as the binder in a unit molecule ratio of 1:1:2:3:1, the unit cell of the hybrid model includes the 2nd to 5th components AS, PS, PI, and MI and coronene or corannulene as the binder in the number of molecules of 1, 1, 2, 3, and 1.

[0047] FIG. 6 and FIG. 7 show a unit cell 10 which is an example of the unit cells arranged in a three-dimensional space. Specifically, FIG. 6 is an explanatory diagram showing the behavior of a hybrid model of a molecular model of a coal material and a molecular model of coronene in three dimensions. FIG. 7 is an explanatory diagram showing the behavior of a hybrid model of a molecular model of a coal material and a molecular model of corannulene in three dimensions. The unit cell 10 is composed of a plurality of molecular models (molecular model group) 10a constituting the coal material and a molecular model 10b or 10c of the binder. The molecular model 10b represents coronene, and the molecular model 10c represents corannulene.

[0048] Next, the total intermolecular interaction of the unit cell 10 is measured using the software described above. Then, the molecular arrangement of the unit cell 10 is changed at each of the predetermined time intervals (e.g., 1 fs) described above, and the total intermolecular interaction of the unit cell 10 is calculated again. Here, when changing the molecular arrangement, the arrangement of each molecular model is determined so that the total intermolecular interaction of the unit cell 10 decreases. This process is performed for a predetermined number of steps (e.g., 5,000,000 steps (= 5 ns)). At the end of the steps, the total intermolecular interaction converges to a certain value.

[0049] Next, as shown in FIGS. 6 and 7, a box 30 containing the unit cell 10 is arranged in a three-dimensional space. The shape and size of the box 30 are not particularly limited, and for example, it may be a cube with a side length of 5 nm. Of course, the shape of the box 30 is not limited to a cube, and it may be a rectangular parallelepiped or any shape. The size of the box 30 is also not limited. Next, the boxes 30 are connected so that all the molecules constituting the unit cell 10 are accommodated. Note that only one box 30 is shown in FIGS. 6 and 7. In these examples, a part of the unit cell 10 protrudes from the box 30. Therefore, the boxes 30 are connected so that all the molecular models constituting the unit cell 10 are contained inside the connected body of the boxes 30. Of course, when all the molecular models constituting the unit cell 10 fit inside one box 30, it is not necessary to connect the boxes 30. Next, the density of the unit cell 10 is calculated by dividing the mass of the unit cell 10 by the total volume of the box 30 (or the connected body of the boxes 30 when the boxes 30 are connected). Then, the reciprocal of this density is used as the specific volume of the mixture model. The above process is performed within a predetermined temperature range at predetermined temperature intervals (e.g., at 50 °C intervals within the range of 0 to 600 °C) to obtain the specific volume at each temperature.

[0050] On the other hand, a unit cell composed only of the molecular model of the coal material is constructed, and the same processing as the above-described processing is performed. That is, the molecular models constituting the unit cell of the coal material are randomly arranged in the three-dimensional space. Here, the unit cell of the molecular model of the coal material contains each component (component of the coal material) constituting the molecular model of the coal material in the minimum number of the above unit molecule ratios. For example, when the mixed model contains the second to fifth components AS, PS, PI, and MI in a unit molecule ratio of 1:1:2:3, the unit cell of the molecular model of the coal material contains the second to fifth components AS, PS, PI, and MI in the number of molecules of 1, 1, 2, and 3.

[0051] FIG. 8 shows a unit cell 10' which is an example of the unit cell arranged in the three-dimensional space. That is, FIG. 8 is an explanatory diagram showing the behavior of the molecular model of the coal material three-dimensionally. The unit cell 10' is composed of a plurality of molecular models (molecular model group) constituting the coal material.

[0052] Next, the total intermolecular interaction of the unit cell 10' is calculated using the above-described software. Then, the molecular arrangement of the unit cell 10' is changed every predetermined time interval (for example, 1 fs) described above, and the total intermolecular interaction of the unit cell 10' is calculated again. Here, when changing the molecular arrangement, the arrangement of each molecular model is determined so that the total intermolecular interaction of the unit cell 10' decreases. This process is performed for a predetermined number of steps (for example, 5,000,000 steps (= 5 ns)). At the end of the steps, the total intermolecular interaction generally converges to a certain value.

[0053] Next, as shown in FIG. 8, a box 30 for accommodating the unit cell 10' is arranged in a three-dimensional space. The characteristics of the box 30 are as described above. Next, the boxes 30 are connected so that all the molecules constituting the unit cell 10' are accommodated. Note that only one box 30 is shown in FIG. 8. In this example, a part of the unit cell 10' protrudes from the box 30. Therefore, the boxes 30 are connected so that all the molecular models constituting the unit cell 10' are contained inside the connected body of the boxes 30. Of course, when all the molecular models constituting the unit cell 10' fit within one box 30, there is no need to connect the boxes 30. Next, the density of the unit cell 10' is calculated by dividing the mass of the unit cell 10' by the total volume of the box 30 (or the connected body of the boxes 30 when the boxes 30 are connected). Next, the reciprocal of this density is taken as the specific volume of the molecular model of the coal material. The above processing is performed at predetermined temperature intervals (for example, at 50°C intervals within the range of 0 to 600°C) within a predetermined temperature range to obtain the specific volume at each temperature. Note that the temperature of the molecular model of the coal material here is assumed to be the temperature of the coal material.

[0054] Next, the specific volumes (the specific volume of the molecular model of the coal material or the specific volume of the mixed model) obtained in each of the above processes are summarized in a graph. An example is shown in FIGS. 9 to 11. The horizontal axis in FIG. 9 indicates the temperature (°C) of the coal material, and the vertical axis indicates the specific volume (SV) (cm 3 / g) of the molecular model of the coal material. The point P1 indicates the calculated values of the temperature and specific volume of the coal material, the graph L1 is the approximate straight line of the point P1 on the high-temperature side, and the graph L2 is the approximate straight line of the point P1 on the low-temperature side. The approximate straight line is obtained, for example, by the least squares method. Then, the temperature corresponding to the intersection of the graphs L1 and L2 is taken as the glass transition point of the coal material. In the example of FIG. 9, there is an intersection of the graphs L1 and L2 in the region A1, and the temperature corresponding to the intersection is 286°C. Therefore, in this example, the glass transition point (Tg) of the coal material is 286°C.

[0055] Incidentally, the glass transition point may be determined, for example, by the following method. That is, in this example, the temperature at which the rate of change of the specific volume with respect to temperature changes is determined as the glass transition point (glass transition temperature). This is determined as the intersection of the regression lines of the point groups on the low-temperature side and the high-temperature side on the graph. Alternatively, for example, when the specific volume is determined at n different temperatures of T1 to Tn, the correlation coefficient when performing linear regression on (n - 2) points of T3 to Tn is R 2 (1). When Rsum(1)=1+R 2 (1), and then, when the correlation coefficients when performing linear regression on the point groups of T1 to T3 and T4 to Tn are respectively R 2 (2), R 2 (3), Rsum(2)=R 2 (2)+R 2 (3) is obtained. Subsequently, sequentially, Rsum(n - 2)=R 2 (n - 2)+R 2 (n - 1) is obtained up to, and further, the correlation coefficient R 2 (n - 1) when performing linear regression on the point group from T1 to T(n - 2) is obtained, and Rsum(n - 1)=R 2 (n - 1)+1 is obtained. Among Rsum(1) to Rsum(n - 1), when the maximum value is Rsum(k), the temperature corresponding to the intersection of the regression lines of the point groups of T1 to T(k - 1) and T(k) to Tn may be determined as the glass transition point. In the examples described later, the glass transition point was determined by this method.

[0056] The horizontal axis of FIG. 10 shows the temperature (°C) of the mixed model A (a mixed model of the molecular model of the coal material and coronene), and the vertical axis shows the specific volume (SV) (cm 3 / g) of the mixed model A. The point P2 shows the calculated values of the temperature and specific volume of the mixed model A, the graph L3 shows the approximate straight line of the point P2 on the high-temperature side, and the graph L4 shows the approximate straight line of the point P2 on the low-temperature side. The approximate straight line is obtained, for example, by the least squares method. Then, the temperature corresponding to the intersection of the graphs L3 and L4 is taken as the glass transition point of the coal material. In the example of FIG. 10, there is an intersection of the graphs L3 and L4 in the region A2, and the temperature corresponding to the intersection is 247°C. Therefore, in this example, the glass transition point (Tg) of the mixed model A is 247°C.

[0057] The horizontal axis of FIG. 11 indicates the temperature (°C) of the mixed model B (a mixed model of the molecular model of the coal material and corannulene), and the vertical axis indicates the specific volume (SV) (cm 3 / g) of the mixed model B. The point P3 indicates the calculated values of the temperature and specific volume of the mixed model B. The graph L5 is the approximate straight line of the point P3 on the high-temperature side, and the graph L6 is the approximate straight line of the point P3 on the low-temperature side. The approximate straight line is obtained, for example, by the least squares method. Then, the temperature corresponding to the intersection of the graphs L5 and L6 is defined as the glass transition point of the coal material. In the example of FIG. 11, there is an intersection of the graphs L5 and L6 in the region A3, and the temperature corresponding to the intersection is 411 °C. Therefore, in this example, the glass transition point (Tg) of the mixed model B is 411 °C.

[0058] As described above, the modeling measurement method has been explained. However, the glass transition point acquisition process is not limited to this example, and the glass transition point may be directly measured using DSC. In this case, the glass transition point of the coal material (or a mixture of the coal material and the binder mixed at a desired mixing ratio) is directly measured using an appropriate DSC measuring device. In this case, in the measurement of the glass transition point, the endothermic peak due to the vaporization of molecules with a small molecular weight may overlap with the endothermic peak due to thermal expansion, and the measurement accuracy of the glass transition point may be slightly reduced. From such a viewpoint, the modeling measurement method is preferable.

[0059] <1-2. Evaluation process> In the evaluation process, based on the glass transition point of the mixture (mixing model) obtained for each binder, the effect of improving the expansibility of each binder on the coal material is evaluated. For example, it may be evaluated that the smaller the glass transition point obtained for each binder is compared to the glass transition point of the coal material, the greater the effect of improving the expansibility of the binder. For example, when the glass transition point obtained for each binder is 15°C or more lower than the glass transition point of the coal material, it may be evaluated that the effect of improving the expansibility of the binder is great. As described above, the lower the glass transition point of the coal material, the lower the temperature at which the coal material charged into the coke oven softens and melts, and thus stronger coke is produced. Incidentally, for a binder whose glass transition point of the mixture with the coal material is different from that of the binder for which the glass transition point has already been obtained, the glass transition point of the mixture of the coal material and the binder is obtained and compared with the already obtained glass transition point, whereby the effect of improving the expansibility of the binder may be evaluated.

[0060] In the examples of FIGS. 6 to 11, the glass transition point of the coal material is 286°C, the glass transition point of the mixture (mixing model A) obtained for coronene is 247°C, and the glass transition point of the mixture (mixing model B) obtained for corannulene is 411°C. Therefore, for this coal material, coronene is a binder with a better effect of improving expansibility than corannulene. It should be noted that it can be evaluated that the smaller the glass transition point obtained for each binder is compared to the glass transition point of the coal material, the greater the effect of improving the expansibility of the binder. Therefore, for example, if there is a binder whose glass transition point of the mixture with the coal material showing the characteristics of FIG. 9 is lower than 247°C, that binder is a binder with a better effect of improving expansibility than coronene.

[0061] In the examples of FIGS. 6 to 11, the reason why the expansion improvement effect of coronene is superior to that of corannulene is not clear. If we consider the reason, it is known that the van der Waals force between the molecules constituting the caking coal acts stronger than that between the molecules constituting the non-caking coal. On the other hand, since coronene has a structure with higher planarity compared to corannulene (see FIGS. 5(a) and (b)), it is easy to penetrate between the molecules of the coal material against the van der Waals force. And the coronene that has penetrated between the molecules of the coal material relaxes the van der Waals force acting between the molecules of the coal material. That is, it lowers the glass transition temperature. As described above, when the glass transition temperature of the coal material decreases, the coal material charged into the coke oven starts to soften and melt at a lower temperature. Therefore, components that do not melt at that temperature dissolve in the region melted at a low temperature, and as a result, the softened and melted region expands, so a stronger coke is produced. Considering these, the coal materials used in the examples of FIGS. 6 to 11 contain more caking components and have higher compatibility with coronene (the addition of coronene reduces the van der Waals force, that is, lowers the glass transition temperature, and softening and melting start from a lower temperature).

[0062] Of course, this judgment is only an example, and it is quite possible that the above judgment will change if the coal material changes. For example, for a coal material showing characteristics different from those in FIG. 9, it is quite possible that the glass transition temperature of the mixture with corannulene is lower than that of the mixture with coronene. In this case, the expansion improvement effect on that coal material is superior for corannulene.

[0063] As described above, according to the present embodiment, since the expansion improvement effect of the binder can be evaluated based on the glass transition point of the mixture of the coal material and the binder, the expansion improvement effect of the binder can be evaluated without conducting large-scale tests using a Geisel blast meter or a dilatometer. Further, as shown in the examples described later, the evaluation results according to the present embodiment also match the test results using a Geisel blast meter. Therefore, according to the present embodiment, the expansion improvement effect of the binder can be appropriately and easily evaluated. Note that the expansion improvement effect in the present embodiment is evaluated by, for example, the maximum expansion rate defined in JIS M 8801. The larger the maximum expansion rate, the greater the expansion improvement effect. Note that in the present embodiment, the expansion improvement effect can be evaluated without conducting a test according to JIS M 8801.

[0064] Furthermore, in the glass transition point acquisition step, a molecular model of the coal material may be constructed by modeling the molecules constituting the coal material, and further, a molecular model of the binder may be constructed by modeling the molecules constituting the binder. Then, the specific volume of the mixed model of the molecular model of the coal material and the molecular model of the binder may be obtained at a plurality of temperatures by the molecular dynamics calculation method, and the glass transition point of the mixture may be obtained based on the correlation graph between the specific volume and temperature of the mixed model. In this case, the behavior of relatively low molecular weight molecules can also be more accurately reflected in the calculation of the glass transition point.

[0065] Furthermore, in the glass transition point acquisition step, a molecular model of the coal material may be constructed by modeling the molecules constituting the coal material, and the specific volume of the molecular model of the coal material may be obtained at a plurality of temperatures by the molecular dynamics calculation method. Then, based on the correlation graph between the specific volume and temperature of the molecular model of the coal material, the glass transition point of the coal material is obtained, and in the evaluation step, based on the glass transition point of the coal material and the glass transition point of the mixture obtained for each binder, the expansion improvement effect of each binder with respect to the coal material may be evaluated. Thereby, the expansion improvement effect of the binder can be evaluated more accurately.

[0066] Furthermore, in the evaluation step, it may be evaluated that the smaller the glass transition point obtained for each binder is with respect to the glass transition point of the coal material, the greater the expansion improvement effect of the binder. In this case, the expansion improvement effect of the binder can be evaluated more accurately.

[0067] <2. Method for producing coke> Next, a method for producing coke using the above-described method for evaluating a binder will be described. The method for producing coke according to the present embodiment is to determine a binder to be added to a coal material based on the above-described method for evaluating a binder, and produce coke using the determined binder and the coal material.

[0068] As a specific method for selecting a binder, for example, the following method can be mentioned. First, the glass transition point of the coal material used in the production of coke is obtained according to the above-described method for evaluating a binder. On the other hand, the glass transition point of a mixture (mixing model) of the binder and the coal material to be used is obtained according to the above-described method for evaluating a binder. Then, a binder whose glass transition point of the mixture is lower than that of the coal material is selected. Then, the difference in glass transition point (glass transition point of the coal material - glass transition point of the mixture of the binder and the coal material) is calculated for each selected binder, and a binder with the largest difference may be selected. Alternatively, a target value may be set for the difference, and a binder whose difference is greater than the target value may be selected. For example, among the binders whose difference is greater than the target value, the one that is most easily available (e.g., low cost, etc.) or easy to handle may be selected.

Example

[0069] To verify the effects of the present embodiment, the following examples (test examples) were conducted. Of course, the present invention is not limited to the examples described below. It is obvious that those having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and these are also naturally understood to belong to the technical scope of the present invention.

[0070] First, a molecular model of the coal material was constructed. As the coal materials, Coal I (caking coal) and Coal II (non-caking coal) were used. The coal material was put into the above-described magic solvent and stirred well. As a result, the coal material was fractionated into a first component MS (a component dissolved in the magic solvent) and a fifth component MI (a component not dissolved in the magic solvent), which is the extraction residue.

[0071] Next, the first component MS was put into acetone and stirred well. As a result, the first component MS was fractionated into a second component AS (a component dissolved in the second solvent 110) and an extraction residue AI (a component not dissolved in the second solvent 110).

[0072] Next, the extraction residue AI was put into pyridine and stirred well. As a result, the extraction residue AI was fractionated into a third component PS (a component dissolved in the third solvent 120) and a fourth component PI (a component not dissolved in the third solvent 120), which is the extraction residue.

[0073] By the above steps, the coal material was fractionated into four components, namely, the second to fifth components AS, PS, PI, and MI. The above-described first component MS is composed of the second to fourth components AS, PS, and PI.

[0074] Next, elemental analysis of the second to fifth components AS, PS, PI, and MI (analyzed here in accordance with JIS M 8813), 1 1H NMR measurement, 13By performing 13C NMR measurement and further Gel Permeation Chromatography (GPC) measurement, the constituent elements, molecular structures, and weight-average molecular weights of the second to fifth components AS, PS, PI, and MI were specified. Subsequently, the average molecular structures (i.e., molecular models) of the second to fifth components AS, PS, PI, and MI were constructed to conform to the respective analytical values. The average molecular structures of the second to fifth components AS, PS, PI, and MI obtained from Coal I are shown in FIGS. 1 to 4. The AS, PS, and MI obtained from Coal II are shown in FIG. 14. Here, the average molecular structure was determined from the above-described viewpoints.

[0075] As described above, the components contained in the coal material are not necessarily limited to the second to fifth components AS, PS, PI, and MI, and may include (or instead of) other components in addition to the second to fifth components AS, PS, PI, and MI. Here, in order to simplify the molecular dynamics calculation, the treatment was advanced on the assumption that the average molecular structures of the components contained in the coal material are those shown in FIGS. 1 to 4 and FIG. 14.

[0076] Subsequently, based on the mass ratios and molecular weights of the second to fifth components AS, PS, PI, and MI, the molecular number ratios (unit molecular number ratios) of the second to fifth components AS, PS, PI, and MI were determined. As a result, for Coal I and Coal II, the mass ratios of the second to fifth components AS, PS, PI, and MI were 4.2:13.8:18.5:65.4 and 6.5:16.3:0.3:75.8, respectively. Although the total slightly exceeds 100, this is due to reasons such as a very small amount of solvent remaining. In any case, it does not affect the subsequent calculations. Therefore, the unit molecular number ratios of the second to fifth components AS, PS, PI, and MI were 1:1:2:3 and 1:1:0:4 for Coal I and Coal II, respectively. Subsequently, based on these data, molecular models of Coal I and Coal II were constructed. The molecular model of the coal material has the second to fifth components AS, PS, PI, and MI, and the second to fifth components AS, PS, PI, and MI have the average molecular structures described above. Also, the molecular model of the coal material has the second to fifth components AS, PS, PI, and MI in the unit molecular number ratios described above.

[0077] Next, the molecules constituting the binder were modeled. Here, in order to simplify the molecular dynamics calculation and facilitate the selection of an appropriate binder, for Coal I, the binder was assumed to be composed of a single component (e.g., coronene or corannulene). Therefore, the molecular structure of the component constituting the binder directly becomes the average molecular structure (molecular model) of the binder. Fig. 5(a) shows the molecular model of coronene, and (b) shows the molecular model of corannulene. The upper figure is a plan view, and the lower figure shows a side view. Also, for Coal II, coronene, pyrene, anthracene, and naphthalene were used. The molecular structures of coronene, pyrene, anthracene, and naphthalene are shown in Fig. 15.

[0078] Next, regarding Coal I, assuming that 5% by mass of coronene or corannulene was added to Coal I, a mixed model of the molecular model of the coal material and the molecular model of the binder was constructed. Therefore, the mixed models (Mixed Models A or B) in this test example contain the second to fifth components AS, PS, PI, and MI and coronene or corannulene as the binder in a unit molecular number ratio of 1:1:2:3:1. Regarding Coal II, assuming that any one of coronene, pyrene, anthracene, or naphthalene was added to Coal II at 5% by mass, a mixed model of the molecular model of the coal material and the molecular model of the binder was constructed. Therefore, the mixed models (Mixed Models C to F) for Coal II contain the second to fifth components AS, PS, PI, and MI and any one of coronene, pyrene, anthracene, or naphthalene as the binder in a unit molecular number ratio of 1:1:0:4:1.

[0079] Next, molecular dynamics calculations of the mixed models were performed to obtain the specific volume of the mixed models. The software used for the molecular dynamics calculations was MaterialStudio manufactured by Daikin Industries, Ltd. The COMPASSII force field was used for the molecular dynamics calculations, and under the NPT ensemble, the molecular dynamics calculations were performed at predetermined time intervals (here, 1 fs intervals) for a predetermined number of steps (here, 5,000,000 steps (= 5 ns)). This process was performed within a predetermined temperature range at predetermined temperature intervals (here, 50 °C intervals within the range of 0 to 600 °C) to obtain the specific volume at each temperature.

[0080] The specific calculation method of the specific volume at each temperature is as described above. That is, first, the unit cells of the mixed models were randomly arranged in a three-dimensional space. Here, the unit cell of the mixed model for Coal I contains the second to fifth components AS, PS, PI, and MI and coronene or corannulene as the binder in the number of molecules of 1, 1, 2, 3, 1. Also, the unit cell of the mixed model for Coal II contains the second to fifth components AS, PS, PI, and MI and any one of coronene, pyrene, anthracene, or naphthalene as the binder in the number of molecules of 1, 1, 0, 4, 1.

[0081] The following describes two models for coal I as examples of molecular dynamics calculations of the hybrid model. Figures 6 and 7 show unit cell 10, which is an example of a unit cell arranged in three-dimensional space. Unit cell 10 is composed of a plurality of molecular models (molecular model group) 10a that make up the coal material, and molecular models 10b or 10c of the binder. Molecular model 10b represents coronene, and molecular model 10c represents corannulene. That is, Figure 6 shows the unit cell of hybrid model A, and Figure 7 shows the unit cell of hybrid model B.

[0082] Next, the total intermolecular interactions of unit cell 10 were calculated using the software described above. Then, the molecular arrangement of unit cell 10 was changed every predetermined time interval (here, 1 fs), and the total intermolecular interactions of unit cell 10 were calculated again. Here, when changing the molecular arrangement, the arrangement of each molecular model was determined so that the total intermolecular interactions of unit cell 10 decreased. This process was performed for a predetermined number of steps (here, 5,000,000 steps (= 5 ns)). At the end of the steps, the total intermolecular interactions generally converged to a certain value. The convergence values were different for each temperature.

[0083] Next, as shown in Figures 6 and 7, box 30 containing unit cell 10 was arranged in three-dimensional space. Here, box 30 was a cube with a side length of 5 nm. Next, boxes 30 were connected so that all the molecules constituting unit cell 10 were accommodated. Note that only one box 30 is shown in Figures 6 and 7. In these examples, a part of unit cell 10 protrudes from box 30. Therefore, boxes 30 were connected so that all the molecular models constituting unit cell 10 were contained inside the connected body of box 30. Next, the density of unit cell 10 was calculated by dividing the mass of unit cell 10 by the total volume of the connected body of box 30. Then, the reciprocal of this density was taken as the specific volume of the hybrid model. The above process was performed at predetermined temperature intervals (here, at 50 °C intervals within the range of 0 to 600 °C) within a predetermined temperature range to obtain the specific volume at each temperature.

[0084] On the other hand, a unit cell composed only of the molecular model of the coal material was constructed, and the same process as the above-described process was performed. That is, the molecular models constituting the unit cell of the coal material (coal I) were randomly arranged in three-dimensional space. Here, the unit cell of the molecular model of coal I contains the second to fifth components AS, PS, PI, and MI in the number of molecules of 1, 1, 2, and 3. Similarly, the unit cell of the molecular model of coal II contains the second to fifth components AS, PS, PI, and MI in the number of molecules of 1, 1, 0, and 4.

[0085] FIG. 8 shows a unit cell 10' which is an example of the unit cell arranged in three-dimensional space. The unit cell 10' is composed of a plurality of molecular models (molecular model group) constituting the coal material.

[0086] Next, the total intermolecular interaction of the unit cell 10' was calculated using the above-described software. Then, the molecular arrangement of the unit cell 10' was changed every predetermined time interval (here, 1 fs), and the total intermolecular interaction of the unit cell 10' was calculated again. Here, when changing the molecular arrangement, the arrangement of each molecular model was determined so that the total intermolecular interaction of the unit cell 10' decreased. This process was performed for a predetermined number of steps (here, 5,000,000 steps (= 5 ns)). At the end of the steps, the total intermolecular interaction generally converged to a certain value. The convergence value was different for each temperature.

[0087] Next, as shown in FIG. 8, a box 30 containing the unit cell 10' was arranged in three-dimensional space. Here, the box 30 was also a cube with a side length of 5 nm. Next, the boxes 30 were connected so that all the molecules constituting the unit cell 10' were accommodated. Then, the density of the unit cell 10' was calculated by dividing the mass of the unit cell 10' by the total volume of the connected bodies of the boxes 30. Then, the reciprocal of this density was taken as the specific volume of the molecular model of the coal material. The above process was performed at a predetermined temperature interval (here, at 50 °C intervals within the range of 0 to 600 °C), and the specific volume at each temperature was obtained.

[0088] Next, the specific volumes obtained in each of the above processes (the specific volume of the molecular model of the coal material or the specific volume of the mixed model) were summarized in a graph. The results are shown in Figs. 9 to 11, taking the results for Coal I as an example. The definitions of Figs. 9 to 11 are as described above. The glass transition points were determined from each of the graphs in Figs. 9 to 11 by the method described above. As shown in Figs. 9 to 11, the glass transition point (Tg) of Coal I was 286°C, the glass transition point (Tg) of the mixed model A was 247°C, and the glass transition point (Tg) of the mixed model B was 411°C.

[0089] From the above results, it can be seen that the binder that shows an excellent effect of improving the expansibility of coal materials is coronene. Next, in order to confirm that this judgment is correct, for each of the coal material, mixture A' obtained by adding 5% by mass (mass% based on the coal material) of coronene to the coal material, and mixture B' obtained by adding 5% by mass (mass% based on the coal material) of collanulene to the coal material, the maximum expansion ratio was measured according to JIS B 8801. As a result, the maximum expansion ratio of mixture A' increased by 101% compared to the maximum expansion ratio of the coal material, while the maximum expansion ratio of mixture B' was almost the same as that of the coal material. Therefore, the judgment that the binder showing an excellent effect of improving the expansibility of this coal material is coronene is correct. Next, regarding Coal II, the obtained results will be described. It was found that the glass transition temperature of Coal II is 301°C. The glass transition temperatures obtained from the mixed models in which any one of coronene, pyrene, anthracene, and naphthalene coexisted are shown in Fig. 16. As a result, compared with the case of Coal II alone, in the mixed model in which naphthalene coexisted as a binder molecule in Coal II, the glass transition temperature was 288°C, which was lower than that of pure Coal II. Also, in the case of the mixed model in which coronene coexisted as a binder molecule in Coal II, the glass transition temperature was 284°C, which was lower than that of pure Coal II. The glass transition temperatures in the cases where Coal II coexisted with pyrene and anthracene were all higher than those in the single-component cases. In accordance with JIS M8801, the expansion ratios of Coal II alone and the systems obtained by adding 5% by mass of each binder to Coal II were measured. As a result, as shown in Fig. 17, compared with the case of Coal II alone, the total expansion ratios of the systems obtained by adding 5% by mass of coronene and naphthalene to Coal II increased to 210% and 113% respectively, while the total expansion ratios of the systems obtained by adding 5% by mass of pyrene and anthracene to the coal decreased compared to the single-component case. From the above, for Coal II alone and each system obtained by adding a binder to Coal II, by calculating the glass transition temperature using molecular dynamics calculations, it was shown that when the glass transition temperature of the system with the added binder was lower than that of the system with only coal, the additive could be predicted to have an effect of improving the expansibility of coal. Therefore, the present method is effective not only for highly caking coal but also for coal with relatively low swelling properties such as non-caking coal.

[0090] As a result, it was confirmed that the method for evaluating a binder according to the present embodiment, that is, by evaluating the swelling property improvement effect of the binder based on the glass transition point of the mixture of the coal material and the binder, can accurately evaluate the swelling property improvement effect of the binder.

[0091] As described above, the preferred embodiments and examples of the present invention have been described in detail, but the present invention is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that these also belong to the technical scope of the present invention.

Explanation of Reference Numerals

[0092] 10 Unit cell of the mixed model 10' Unit cell of the molecular model of the carbon material 10a Molecular model of the coal material 10b Molecular model of coronene 10c Molecular model of corannulene

Claims

1. Obtaining the glass transition point of the coal material that is the raw material of coke, and further obtaining the glass transition points of mixtures of the coal material and binders mixed with the coal material for a plurality of types of the binders, a glass transition point obtaining step; An evaluation step of evaluating the expansion property improvement effect of each binder with respect to the coal material based on the glass transition point of the coal material and the glass transition points of the mixtures obtained for each binder, characterized by including, a method for evaluating a binder, In the glass transition point obtaining step, Constructing a molecular model of the coal material by modeling the components constituting the coal material, obtaining the molecular model specific volume of the coal material at a plurality of temperatures by a molecular dynamics calculation method, and based on the correlation graph between the specific volume of the molecular model of the coal material and the temperature, obtaining the glass transition point of the coal material, or measuring the glass transition point of the coal material using differential scanning calorimetry, Constructing a molecular model of the coal material by modeling the components constituting the coal material, further constructing a molecular model of the binder by modeling the components constituting the binder, obtaining the specific volume of a mixed model of the molecular model of the coal material and the molecular model of the binder at a plurality of temperatures by a molecular dynamics calculation method, and measuring the glass transition point of the mixture based on the correlation graph between the specific volume of the mixed model and the temperature, or measuring the glass transition point of the mixture using differential scanning calorimetry A method for evaluating a binder, characterized by the above.

2. Obtaining the glass transition point of the coal material that is the raw material of coke, and further obtaining the glass transition point of a mixture of the coal material and a binder mixed with the coal material, a glass transition point obtaining step; An evaluation step of evaluating the expansion property improvement effect of the binder with respect to the coal material based on the glass transition point of the coal material and the glass transition point of the mixture, characterized by including, a method for evaluating a binder, In the glass transition point obtaining step, Constructing a molecular model of the coal material by modeling the components constituting the coal material, obtaining the molecular model specific volume of the coal material at a plurality of temperatures by a molecular dynamics calculation method, and based on the correlation graph between the specific volume of the molecular model of the coal material and the temperature, obtaining the glass transition point of the coal material, or measuring the glass transition point of the coal material using differential scanning calorimetry, A molecular model of the carbon material is constructed by modeling the components constituting the carbon material, and a molecular model of the binder is constructed by modeling the components constituting the binder. The specific volume of the mixed model of the molecular model of the carbon material and the molecular model of the binder is obtained at a plurality of temperatures by the molecular dynamics calculation method, and based on the correlation graph between the specific volume of the mixed model and the temperature, the glass transition point of the mixture is measured, or the differential scanning calorimetry is used to measure the glass transition point of the mixture. A method for evaluating a binder, characterized by the above.

3. In the evaluation step, The method for evaluating a binder according to claim 1 or 2, characterized in that the smaller the glass transition point obtained for each binder is with respect to the glass transition point of the carbon material, the greater the expansion improvement effect of the binder is evaluated.

4. The method for evaluating a binder according to claim 1 or 2, characterized in that when the glass transition point obtained for each binder is 15 ° C or more lower than the glass transition point of the carbon material, the expansion improvement effect of the binder is evaluated as large.

5. The method for evaluating a binder according to any one of claims 1 to 4, characterized in that the carbon material is strongly caking coal or non-finely caking coal.

6. A method for producing coke, characterized in that a binder to be added to a carbon material is determined based on the method for evaluating a binder according to any one of claims 1 to 5, and coke is produced using the determined binder and the carbon material.

Images