JP2014043545A - Method for reforming coal and method for producing coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and efficient method for reforming coal, in which a solid powder is used as a reforming agent, and a reforming step of coal and a production step of coke can be performed simultaneously, when the flow property, which is a characteristic of coal, is improved for producing high-strength coke.SOLUTION: A method for reforming coal of the present invention improves the flow property (maximum fluidity (MF)) of coal by adding a primary or secondary amine-based compound having an aromatic ring, such as phenothiazine and carbazole, to coal used as a starting material for coke. More specifically, the flow property of coal is improved by mixing coal with a primary or secondary amine compound having an aromatic ring, such as phenothiazine and carbazole, and then subjecting the coal mixed with the amine-based compound to carbonization.

Description

  The present invention relates to a method for reforming coal, which is a raw material for coke used as an ironmaking raw material, and more particularly to a method for reforming coal such as blended coal for producing high-strength blast furnace coke. The present invention relates to a method for producing coke using a reforming method.

  Blast furnace coke is used in the blast furnace as a reducing material, a heat source, and a support material for maintaining air permeability. Blast furnace coke, which plays such a role, deteriorates the air permeability of the blast furnace when pulverized when charged into the blast furnace, so that it is required to have high strength to prevent it. Therefore, various techniques for producing high-strength coke by devising a pretreatment method for coal as a coke raw material have been studied. As an example, the coke strength is adjusted by optimizing the particle size distribution of the coal before charging into the coke oven, that is, by adjusting the particle size distribution so that the proportion of particles having a particle size of 3 mm or less is 70 to 90% by mass. A control method is known.

  In addition, when producing coke for blast furnace, usually, blended coal in which multiple brands of coal are mixed is used. Therefore, conventionally, methods for estimating the strength of coke produced using blended coal as a raw material have been studied. It was. Among them, in particular, a method based on a “coke strength estimation method using substrate strength and fluidity as an index” is generally performed. This method is a method for estimating coke strength as parameters of two indices, vitrinite average reflectance (average value of Ro) and maximum flow rate (MF) of a Gieseler plastometer, as properties of coal.

  That is, as a factor when carbonizing coal to produce coke, two characteristics are vitrinite average reflectance (Ro) indicating the degree of coal coalification and maximum fluidity (MF) indicating the cohesiveness of coal. And the strength of the coke produced is estimated based on the combination of these two characteristics. That is, in order to ensure the strength of the coke to be produced, the raw coal is blended so that the vitrinite average reflectance (Ro) and the maximum fluidity (MF) of the blended coal are within a predetermined range. The maximum fluidity (MF) indicating the fluidity of coal is represented by the rotational speed (ddpm) or logarithmic value (logMF = log [ddpm]) of the stirring bar for testing from the characteristics of the test method. Here, “ddpm” is an abbreviation for Dial Division per Minute.

  Specific values for the maximum fluidity of the blended coal include a logarithmic value (logMF) of the maximum fluidity of the blended coal, that is, a weighted average value of the logarithmic value (logMF) of the maximum fluidity of each coking coal to be mixed. In general, various coals are blended so as to be in the range of ˜4, preferably in the range of 2.0 to 3.5. However, since the range of the optimum maximum fluidity (logMF) of the blended coal differs depending on the characteristics of the coke oven to be used and the production conditions, it may occur outside the above range.

  For example, Non-Patent Document 1 shows that fluidity is a very important factor for producing high-strength coke. Furthermore, in order to produce high-strength coke, it is important to optimize the maximum fluidity (MF) of the coal blend by combining several brands, and the fluidity of the coal blend is insufficient. It is described that the coke strength is lowered when it is present.

  Blast furnace coke is produced by mixing and blending high quality caking coal (strong caking coal) with non-fine caking coal, which is cheaper than this good quality caking coal. There is a global shortage of good-quality caking coal that is advantageous for coke production. If non-slightly caking coal can be modified to have the same or similar characteristics as good quality caking coal, it will not only be possible to compensate for the shortage of good quality caking coal, but it will also be possible to reduce the production cost of coke. . Therefore, technology development for producing high-strength coke using coal with low caking properties (non-caking coal) has been underway.

  For example, in Patent Document 1, as a method for reforming and using coal having low caking properties, non-fine caking coal is pulverized more finely than high quality caking coal, and then dried, tar, heavy oil, A raw material pretreatment method has been proposed in which a binder such as pitches is kneaded into pseudo particles. Patent Document 2 proposes a method for producing a high-strength coke by adding and mixing a heavy tar fraction to raw coal and dry-distilling the raw coal mixed with the heavy tar fraction. .

  Patent Document 3 discloses a coke reforming method in which fine oxide powder having an effect of improving gasification reactivity is supported on the surface of coke having high hot strength by a wet loading method to improve the gasification reactivity of coke. Proposed. In Patent Document 4, non-caking coal is mixed with a non-hydrogen donating solvent to form a slurry, the slurry is heated to 300 to 420 ° C. to perform solvent extraction, and the heated slurry is mixed with a liquid part and a non-liquid. And separating the solvent from the liquid part to obtain extracted charcoal, obtaining non-extracted charcoal from the non-liquid part, and using the extracted charcoal excellent in softening fluidity as a raw material for coke. Charcoal reforming methods have been proposed. In Patent Document 5 and Patent Document 6, low-grade coal containing a large amount of oxygen atoms is heated together with heavy oils at a predetermined temperature to cause the decomposition products of heavy oils to adhere to the surface of the low-grade coal. A method for efficiently modifying low-grade coal into artificial caking coal without generating a large amount of water during the treatment process is described.

  By the way, non-patent document 2 describes the results of mixing coal with various plastics and investigating the caking property and fluidity of coal at that time. It has been reported that the effect of improving is not expressed.

  In the coke manufacturing industry, the boundary between high-quality caking coal and non-caking caking coal is not clearly defined. However, as described above, when producing blast furnace coke, considering that coal is often blended so that the maximum fluidity (logMF) is in the range of 1 to 4, the maximum fluidity ( It can be said that a coal whose log MF) falls within a range of 1.0 or less is a low-grade coal that is not suitable for blast furnace coke.

JP-A-10-183136 JP 11-43675 A JP 2003-89808 A JP 2006-70182 A JP 2009-13221 A JP 2009-13222 A

Takashi Miyazu et al., Nippon Steel Pipe Technical Report, 67 (1975), p.125 Seiji Nomura et al., Journal of the Japan Institute of Energy, 81 (2002), p.728

  When producing low-grade coal and producing coke for blast furnace using the modified low-grade coal as part or all of the raw coal, from the viewpoint of improving productivity, the low-grade coal reforming process and coke production process It is desirable to carry out simultaneously. Further, as a coal modifier, a method of blending or charging a solid substance similar to coal, desirably powder, into coal is simple. It is disadvantageous in terms of cost to go through a heat treatment step different from that of the coke oven as a reforming step of low-grade coal, or through a step of giving oxide or metal powder to coal or coke.

  Examining the above prior art from this point of view, Patent Literatures 1, 4, 5, and 6 are technologies for pre-treating coal in the stage before coke production, and Patent Literature 3 describes oxide fine particles on the surface of coke. This is a technology for supporting powder. In Patent Document 2, it is necessary to add tar to raw coal and mix it with raw coal, and although it is a simple process, since liquid tar is used as a modifier, mixing using a dedicated mixing container Pre-processing called a process is necessary. In other words, the conventional technique has a point to be improved. Non-patent document 2 is out of the question because no effect is seen.

  The present invention has been made in view of such circumstances, and the object of the present invention is to improve the fluidity, which is a characteristic of coal, in order to produce high-strength coke. And a simple and efficient coal reforming method capable of simultaneously performing a coal reforming step and a coke production step. That is, it is to provide a method for improving the fluidity of coal by adding solid powder having an effect of improving the fluidity of coal to coal or blended coal as a coke raw material. Another object of the present invention is to provide a method for producing high-strength coke using this coal reforming method.

The gist of the present invention for solving the above problems is as follows.
[1] A coal reforming method, wherein a primary or secondary amine compound having an aromatic ring is added to coal used as a coke raw material to improve the fluidity of the coal.
[2] It is characterized by mixing the coal and the primary or secondary amine compound having an aromatic ring, and dry-distilling the coal mixed with the primary or secondary amine compound having an aromatic ring. The method for reforming coal according to the above [1].
[3] The method for reforming coal according to [1] or [2] above, wherein the primary or secondary amine compound having an aromatic ring is phenothiazine and / or carbazole.
[4] The method for reforming coal according to any one of [1] to [3] above, wherein the coke is blast furnace coke.
[5] A method for producing coke, characterized in that coke is produced using the coal reforming method according to any one of [1] to [4].

  According to the present invention, the fluidity of coal used as a raw material for coke is obtained by a simple method of adding a primary or secondary amine compound having an aromatic ring such as phenothiazine or carbazole to coal. It can be reformed to coal with different fluidity, that is, a characteristic of high maximum fluidity (MF) compared with the time of acquisition, and it is also possible to modify in accordance with the production of coke in a coke oven. Thus, it is possible to easily and efficiently reform coal as compared with the prior art. This reforming has the same effect as securing coal with a high maximum fluidity (MF), and this allows the freedom of blending design when blending multiple brands of coal required for the production of high-strength coke. Is realized. In addition, even if low-grade coal with poor fluidity is used, coke can be produced with the same quality as coke that was conventionally produced using high-grade coal. Reducing coke production costs is achieved.

It is a figure which compares and shows the relationship between the temperature and fluidity | liquidity in A charcoal in an Example by the presence or absence of the addition of phenothiazine. It is a figure which shows the relationship between the temperature in B charcoal in an Example, and fluidity | liquidity by the presence or absence of the addition of phenothiazine. It is a figure which shows the relationship between the temperature in C charcoal in an Example, and a fluidity | liquidity by the presence or absence of the addition of carbazole which is 1 type of the primary or secondary amine type compound which has an aromatic ring. The figure which shows the relationship between the temperature in C charcoal in an Example, and a fluidity | liquidity by the presence or absence of addition of N-phenyl-1- naphthylamine which is 1 type of the primary or secondary amine type compound which has an aromatic ring. It is. It is a figure which shows the relationship between the addition amount of a phenothiazine, and the maximum fluidity (MF). It is a figure which shows the relationship between the addition amount of carbazole and the maximum fluidity (MF). It is a figure which shows the relationship between the addition amount of hydroquinone, and the maximum fluidity (MF).

  Hereinafter, the present invention will be described in detail.

  In order to improve the fluidity of coal, which is necessary for obtaining high-strength coke, that is, to increase the maximum fluidity (MF) of a Gieseler plastometer, the present inventors have used various solids. A method for reforming coal by adding to coal was studied. As described above, the maximum fluidity (MF) of the Gisela plastometer is generally taken as one of the important characteristics of coal that affects the quality of coke.

  Researches to improve the fluidity of coal have been conducted in the past, but most of them use heavy oil, tars, or extracts / extracts extracted beforehand from coal using various solvents. These are kneading methods, which are far from simple methods, require dedicated equipment, and have complicated processes. Furthermore, in addition to that, it has been studied to perform a method of applying coal or the like to the surface of coal and activating the coal in parallel.

  On the other hand, in Non-Patent Document 2 in which various plastics are added to coal to study the influence on fluidity, it has been reported that the effect of improving the fluidity of coal due to the addition of plastic does not appear.

  The present inventors conducted a confirmation test of coal fluidity improvement effect using various compounds, and as a result, consisted of a mixture of various substances typified by heavy oil, tars, extracts from coal, etc. It has been found that the addition of a single compound or a combination of several single compounds to coal, rather than a substance, improves coal flow properties, contrary to previous knowledge. Specifically, it has been found that the flow characteristics of coal are improved by adding a primary or secondary amine compound having an aromatic ring such as phenothiazine or carbazole to coal.

  Here, the primary or secondary amine compound having an aromatic ring corresponds to a primary amine corresponding to a structure in which one hydrogen of ammonia is substituted or a structure in which two hydrogens of ammonia are substituted. Secondary amines, and those substituents containing an aromatic ring. An aromatic ring refers to an aromatic ring having a cyclic structure such as a benzene ring and a naphthalene ring.

Phenothiazine, which is a primary or secondary amine compound having an aromatic ring, has a chemical formula of C ₁₂ H ₉ NS, a melting point of 184 ° C., a solid at ordinary temperature, and a boiling point of 371 ° C. As examples of primary or secondary amine compounds having other aromatic rings, the chemical formula of carbazole is C ₁₂ H ₉ N, the melting point is 246 ° C., and the chemical formula of N-phenyl-1-naphthylamine is C ₁₆ H ₁₃ N, The melting point is 60 ° C. These are solid at room temperature.

  In general, when coal provided as a raw material for coke for blast furnace is heated, softening and melting starts from around 350 ° C. That is, generally the softening and melting temperature range of coal is 350 ° C. or higher, and softening and melting proceeds in the range of 550 ° C. or lower. At the time of softening and melting, a thermal decomposition reaction of coal occurs and the mass is remarkably reduced.

  Phenothiazine, carbazole, and N-phenyl-1-naphthylamine are known as antioxidants, inhibitors of polymer chain reactions, and inhibitors. When the present inventors mix primary or secondary amine compounds having an aromatic ring such as phenothiazine with coal, the characteristics of the primary or secondary amine compounds having an aromatic ring such as phenothiazine described above are obtained. It has been found that the fluidity of coal is improved. That is, it was found that the fluidity was improved by mixing coal and a primary or secondary amine compound having an aromatic ring such as phenothiazine and dry distillation. Here, dry distillation is an operation in which air is blocked and solid organic matter (such as phenothiazine) is strongly heated.

  Although the mechanism by which the fluidity of coal is improved by the addition of a primary or secondary amine compound having an aromatic ring has not been clarified in detail, it is presumed as follows. In other words, since primary or secondary amines have a hydrogen donating ability, they donate hydrogen to coal molecules in the dry distillation process, especially in the softening and melting temperature region of coal, temporarily suppressing the polymerization of coal molecules, It is thought that fluidity is improved because of the effect of maintaining the state. Furthermore, many common organic compounds decompose or volatilize at about 300 to 400 ° C., but the aromatic ring has a relatively thermally stable structure, and the compound having an aromatic ring has a relatively boiling point. Therefore, even at 350 ° C. to 450 ° C., which is the softening and melting start temperature of coal, a part of the compound having an aromatic ring remains in the coal and can exert an effect.

  Hereinafter, embodiments of a method for improving coal fluidity by adding a primary or secondary amine compound having an aromatic ring such as phenothiazine according to the present invention will be described.

  The coal whose fluidity is to be improved is pulverized into a particle size of 5.0 mm or less (under a sieve having an opening size of 5.0 mm), preferably a particle size of 5.0 mm or less and at least 70% by mass of the particle size Is a primary or secondary amine compound having an aromatic ring such as phenothiazine in the pulverized coal, pulverized so that the particle size is 3.0 mm or less (under the sieve passing through a sieve having an opening size of 3.0 mm) Mix the powder. At that time, a plurality of primary or secondary amine compounds having an aromatic ring such as phenothiazine and carbazole may be added.

  A mixture of this coal and a powder of a primary or secondary amine compound having an aromatic ring such as phenothiazine is subjected to dry distillation at a temperature of 350 ° C. or higher. Coal for blast furnace coke develops a phenomenon of flowing when heated to 350 ° C. or higher, and this fluidity is improved by adding a primary or secondary amine compound having an aromatic ring. In the above, coal is mixed with a primary or secondary amine compound having an aromatic ring such as phenothiazine at room temperature, but primary or 2 having an aromatic ring such as phenothiazine in the heated coal. A grade amine compound may be added.

  Furthermore, when coke is produced by charging a blended coal with a mixture of multiple brands of coal into a coke oven, one or more of the brands of one or more fragrances such as phenothiazine and carbazole are used. A primary or secondary amine compound powder having a ring is added and mixed, and a mixture of the primary or secondary amine compound powder having an aromatic ring is used as coal constituting the blended coal as coke. It may be manufactured. Coal mixed with a powder of a primary or secondary amine compound having an aromatic ring such as phenothiazine is heated at the time of dry distillation in a coke oven, and when heated, the primary or second having an aromatic ring such as phenothiazine. Grade amine compounds improve fluidity and react with other brands of coal to produce coke.

  The carbonization temperature during the production of coke is generally as high as 1000 to 1300 ° C, but the fluidity improvement effect by primary or secondary amine compounds having an aromatic ring such as phenothiazine is 350 ° C or more and 550 ° C. It develops in the following temperature range, and coal is sufficiently reformed during the heat-up process during dry distillation for coke production. For the purpose of only improving the fluidity of coal with primary or secondary amine compounds having an aromatic ring such as phenothiazine or carbazole without carbonizing coal into coke, a carbonization temperature of 350-550 ° C is sufficient. is there. Also, the carbonization time in this case depends on the type of coal and the like, and therefore can be appropriately determined by conducting a preliminary experiment using a small amount of coal to improve fluidity.

  Also, other compounds mixed with a primary or secondary amine compound having an aromatic ring such as phenothiazine as long as the effect of the primary or secondary amine compound having an aromatic ring such as phenothiazine is not inhibited. May be used as a fluidity improver, and two or more different primary or secondary amine compounds having an aromatic ring may be mixed and used.

  In the coal reforming method according to the present invention, the coal to be reformed is not limited, for example, all of the coal used as a raw material for coke for blast furnace such as strongly caking coal and non-caking coal In particular, it is a reality to target non-slightly caking coal having a low maximum fluidity (MF) alone or a blended coal with several types of non-slightly caking coal. Is. In addition, the primary or secondary amine compound having an aromatic ring such as phenothiazine used as a modifier in the present invention is not particularly defined with respect to the particle size. The particle size is fine, for example, preferably 3 mm or less. The blending amount of the primary or secondary amine compound having an aromatic ring such as phenothiazine with respect to the coal to be modified is less than 0.1% by mass, the effect is not sufficient, and if it exceeds 15% by mass, the cost is very high. Since it will become a high thing, 0.1-15 mass% is preferable. When two or more different kinds of primary or secondary amine compounds having an aromatic ring are mixed and used, the total amount thereof may be in the above range.

  As described above, the primary or secondary amine compound having an aromatic ring such as phenothiazine may be added in powder form, but the form at the time of addition is not particularly limited. For example, you may add in the state shape | molded to the tablet, may melt | dissolve in a solvent etc. and may add as a solution, and may add in a slurry form.

  As described above, according to the present invention, the fluidity of coal used as a raw material for coke can be obtained by a simple method of adding a primary or secondary amine compound having an aromatic ring such as phenothiazine to coal. It can be reformed to coal having different fluidity from that at the time of acquisition, that is, a property having a higher maximum fluidity (MF) than that at the time of acquisition, and further, it is modified in accordance with coke production in a coke oven. It is also possible to improve the fluidity of coal and produce high-strength coke in a simpler and more efficient manner than in the past.

  An example in which phenothiazine is added to improve the fluidity of coal will be described. Table 1 shows main characteristic values of two types of coal (A coal and B coal) subjected to the reforming test. As shown in Table 1, coal A is a low-grade coal having a maximum fluidity (log MF) of 1.0 and a low fluidity that makes it impossible to produce high-strength coke. Is a coal showing a strong caking property with a maximum fluidity (logMF) of 3.3. The amount of inert in Table 1 indicates the amount of inactive ingredients.

  Improvement of fluidity of coal by adding phenothiazine was confirmed by the following procedure. First, coal pulverized to a particle size of 2.0 mm or less and commercially available phenothiazine powder were mixed to prepare a mixed sample of coal and phenothiazine. At this time, the mixing amount of the phenothiazine powder with respect to the coal was adjusted so that the mass ratio of the phenothiazine to the coal was 10% by mass. This mixed powder is charged into a predetermined container defined by the JIS M8801 Gieseller Plastometer method, and the container charged with this mixed powder is charged into a furnace preheated to 300 ° C. based on JIS M8801. The mixture powder was heated to 550 ° C. at 3 ° C./min to raise the temperature of the mixed powder to the softening and melting temperature range of coal. The maximum fluidity (log MF) of coal was measured based on JIS M8801 for this mixed sample.

  In addition, the maximum fluidity (log MF) was measured for plain coal that did not mix phenothiazine (one brand coal that does not mix multiple brands). As comparative examples, polyethylene terephthalate powder (PET), polystyrene powder (PS), dimethyl terephthalate, dibenzothiophene, 4,4'-methylenebis (2,6-di-tert-butylphenol), dibenzyl instead of phenothiazine Disulfide and anthrone were added to coal so that each would be 10% by mass, and the maximum fluidity (log MF) of the coal was also measured for these mixed samples in accordance with JIS M8801. The measurement results are shown in Table 2.

  As shown in Table 2, it was found that by adding phenothiazine to coal, the fluidity was remarkably improved and the maximum fluidity (MF) was increased in both coals A and B. This indicates that addition of phenothiazine is effective in improving the maximum fluidity (MF) regardless of the maximum fluidity (MF) of the raw coal. Furthermore, the maximum fluidity (log MF) after addition of phenothiazine in low-grade A coal is 2.7, which is an appropriate fluidity for producing high-strength coke, and the coking property is improved.

  On the other hand, like phenothiazine, the addition of dimethyl terephthalate, which is a structural unit substance of PET, PS, and PET having an aromatic ring structure in the molecule, showed a phenomenon that the fluidity of coal deteriorates. In addition, when dibenzothiophene having both an aromatic ring and a heterocycle in the molecule was added, there was almost no change in fluidity, and no improvement in fluidity was observed.

  As noted above, phenothiazine is known as an antioxidant, but it is commonly used as an antioxidant for 4,4'-methylenebis (2,6-di-tert-butylphenol), dibenzyl disulfide, and anthrone. Even when added, the effect of improving fluidity was not recognized.

  From the above results, it was found that phenothiazine is a substance having an effect of improving the fluidity of coal.

  The detailed temperature profile of the test result of JIS M8801 with coal and plain coal with phenothiazine addition is shown in FIG. 1 and FIG. FIG. 1 is a diagram showing the relationship between temperature and fluidity in coal A, and FIG. 2 is a diagram showing the relationship between temperature and fluidity in coal B. 1 and 2, the fluidity changes depending on the temperature, and the highest value of fluidity is defined as the maximum fluidity (MF). 3 and 4 described later, the definition of the maximum fluidity (MF) is the same.

  According to FIG. 1, coal A, which has a maximum fluidity (logMF) of 1.0 in the case of plain coal, exhibits fluidity from around 370 ° C. due to the addition of phenothiazine, and the maximum fluidity (logMF) at 440 ° C. Thus, it was confirmed that the maximum fluidity (logMF) reached 2.7. Further, according to FIG. 2, B coal having a maximum fluidity (log MF) of 3.3 at the time of plain coal has a maximum fluidity (log MF) at 425 ° C. by addition of phenothiazine, and the value is 3. Improved to 9.

  Thus, by applying the present invention, it has been found that not only the flow characteristics of low-grade coal are improved, but also the fluidity improving effect is exerted on coal showing strong caking properties. That is, it was confirmed that the flow characteristics of coal can be improved by adding phenothiazine to the coal.

  An example in which the fluidity of coal is modified by adding a primary or secondary amine compound having an aromatic ring will be described. Table 3 shows main characteristic values of the coal (C charcoal) subjected to the reforming test. As shown in Table 3, C coal is a low-grade coal having a maximum fluidity (logMF) of 0.4.

  The improvement in the fluidity of coal by adding a primary or secondary amine compound having an aromatic ring was confirmed by the following procedure. First, coal pulverized to a particle size of 2.0 mm or less is mixed with commercially available carbazole powder or N-phenyl-1-naphthylamine powder as an example of a primary or secondary amine compound having an aromatic ring, A mixed sample with a primary or secondary amine compound having an aromatic ring was prepared. At this time, the mixing amount of the primary or secondary amine compound powder having an aromatic ring with respect to coal is 10% by mass with respect to the mass ratio of the primary or secondary amine compound having an aromatic ring to coal. Prepared. This mixed powder is charged into a predetermined container defined by the JIS M8801 Gieseller Plastometer method, and the container charged with this mixed powder is charged into a furnace preheated to 300 ° C. based on JIS M8801. The mixture powder was heated to 550 ° C. at 3 ° C./min to raise the temperature of the mixed powder to the softening and melting temperature range of coal. The maximum fluidity (log MF) of coal was measured based on JIS M8801 for this mixed sample.

  In addition, the maximum fluidity (logMF) was measured with simple coal not mixed with a primary or secondary amine compound having an aromatic ring.

  As a comparative example, instead of a primary or secondary amine compound having an aromatic ring, acridine is added to coal so as to be 10% by mass, and the maximum fluidity (log MF) of coal according to JIS M8801. Was measured. Table 4 shows the measurement results.

  As shown in Table 4, by adding primary or secondary amine compounds (carbazole and N-phenyl-1-naphthylamine) having an aromatic ring to coal, the fluidity is remarkably improved and the maximum fluidity ( MF) was found to increase.

  On the other hand, like carbazole, it has an aromatic ring structure and nitrogen in the molecule, but the addition of acridine, which is different from carbazole in that the nitrogen form is neither primary amine nor secondary amine, the flow of coal Sex did not improve. Also in Example 1 described above, the addition of a substance other than the primary or secondary amine compound having an aromatic ring showed no effect of improving fluidity.

  From the above results, it was found that a primary or secondary amine compound having an aromatic ring is a substance having an effect of improving the fluidity of coal.

  Detailed temperature profiles of the test results of JIS M8801 with coal and simple coal by addition of carbazole and N-phenyl-1-naphthylamine, which are one of primary or secondary amine compounds having aromatic rings, It shows in FIG.3 and FIG.4. FIG. 3 is a graph showing the relationship between temperature and fluidity in Coal C with and without the addition of carbazole, and FIG. 4 shows the relationship between temperature and fluidity in Coal C and N-phenyl-1-naphthylamine. It is a figure shown by comparison with the presence or absence of addition of.

  As is clear from FIGS. 3 and 4, it can be seen that the maximum fluidity (logMF) is remarkably improved by adding carbazole and N-phenyl-1-naphthylamine to coal.

  An example in which the fluidity of coal is modified by adding a primary or secondary amine compound having an aromatic ring will be described. C charcoal was used for the modification test. Coal C has a maximum fluidity (log MF) of 0.4, and is a low-grade coal with low fluidity that makes it difficult to produce high-strength coke by itself.

  The improvement in the fluidity of coal by adding a primary or secondary amine compound having an aromatic ring was confirmed by the following procedure. First, coal pulverized to a particle size of 2.0 mm or less is mixed with commercially available phenothiazine powder or carbazole powder as an example of a primary or secondary amine compound having an aromatic ring, and coal and 1 having an aromatic ring are mixed. A mixed sample with a secondary or secondary amine compound was prepared. At this time, the mixing amount of the primary or secondary amine compound powder having an aromatic ring with respect to the coal is such that the mass ratio of the primary or secondary amine compound having an aromatic ring to the coal is 0.2 to 9 mass. %.

  This mixed powder is charged into a predetermined container defined by the JIS M8801 Gieseller Plastometer method, and the container charged with this mixed powder is charged into a furnace preheated to 300 ° C. based on JIS M8801. The mixture powder was heated to 550 ° C. at 3 ° C./min to raise the temperature of the mixed powder to the softening and melting temperature range of coal. The maximum fluidity (MF) of coal was measured based on JIS M8801 for this mixed sample. In addition, the maximum fluidity (MF) was measured only with plain coal not mixed with a primary or secondary amine compound having an aromatic ring.

  The measurement results are shown in FIGS. FIG. 5 is a diagram showing the relationship between the added amount of phenothiazine and the maximum fluidity (MF), and FIG. 6 is a diagram showing the relationship between the added amount of carbazole and the maximum fluidity (MF).

  As a comparative example, hydroquinone is added to coal so that it becomes 0.2 to 9% by mass instead of primary or secondary amine compound having an aromatic ring, and the maximum flow of coal according to JIS M8801. The degree (MF) was measured. The measurement results are shown in FIG. FIG. 7 is a diagram showing the relationship between the amount of hydroquinone added and the maximum fluidity (MF).

  As shown in FIGS. 5 and 6, it was found that the addition of 1% by mass of the primary or secondary amine compound (phenothiazine and carbazole) having an aromatic ring improves the fluidity. Further, it was found that by increasing the addition amount, the fluidity was remarkably improved according to the addition amount, and rapidly increased at 4% by mass or more.

  On the other hand, the addition of hydroquinone having no primary or secondary amine group in the molecule did not improve the fluidity of coal. It was found that the addition of up to 1% by mass showed a slight fluidity, but the addition beyond that showed no fluidity at all. In addition to hydroquinone, also in Example 1 described above, it has been shown that the addition of a substance other than the primary or secondary amine compound having an aromatic ring does not show an improvement in fluidity.

  Thus, it has been found that by applying the present invention, an effect of improving fluidity is exhibited with respect to coal. That is, it was confirmed that the flow characteristics of coal can be improved by adding a primary or secondary amine compound having an aromatic ring to the coal.

Claims (5)

  A method for reforming coal, comprising adding a primary or secondary amine compound having an aromatic ring to coal used as a raw material for coke to improve the fluidity of the coal.   The primary coal or secondary amine compound having an aromatic ring is mixed with the coal, and the coal mixed with the primary or secondary amine compound having an aromatic ring is dry-distilled. Item 2. The method for reforming coal according to Item 1.   The method for reforming coal according to claim 1 or 2, wherein the primary or secondary amine compound having an aromatic ring is phenothiazine and / or carbazole.   The method for reforming coal according to any one of claims 1 to 3, wherein the coke is blast furnace coke.   A method for producing coke, characterized in that coke is produced using the coal reforming method according to any one of claims 1 to 4.

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