JP2013124325A - Method for producing ashless coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing ashless coal, with which the yield of the ashless coal is improved even when the ashless coal is produced in a coal-producing area where there is no room for selecting various kinds of raw materials (coal).SOLUTION: A raw material fractionation process to fractionate the coal according to respective predetermined particle sizes is added to the production process of the ashless coal. In order to conduct a series of treatment processes such as an extraction process etc., by using the coal in a predetermined particle size range determined based on the analytical result of the raw material analysis stage to analyze properties of the coal according to the respective predetermined particle sizes, the coal is fractionated by the raw material fractionation process according to the respective particle sizes.

Description

  The present invention relates to a method for producing ashless coal for obtaining ashless coal from which ash is removed from coal.

  As a method for producing ashless coal, for example, there is one described in Patent Document 1. The method for producing ashless coal described in Patent Document 1 is prepared by mixing coal and a solvent to prepare a slurry, heating the resulting slurry to extract a coal component soluble in the solvent, and extracting the coal component. The slurry is separated into a solution part containing a coal component soluble in the solvent and a non-solution part containing a coal component insoluble in the solvent, and then the solvent is separated from the separated solution part to remove ashless coal. It is to get. The method for producing ashless coal described in Patent Document 1 uses, as a raw material for ashless coal, coal obtained by mixing caking coal with general coal when adopting the gravity sedimentation method for separating the solution portion and the non-solution portion. It is characterized by that.

  According to the production method described in Patent Document 1, the sedimentation rate of the solvent-insoluble component is improved when the gravity sedimentation method is performed, and as a result, ashless coal from which ash is sufficiently removed is produced with high efficiency and at low cost. be able to.

JP 2009-227718 A

  Here, the yield of ashless coal when producing ashless coal is almost determined by the coal type of the raw material (coal). According to the manufacturing method described in Patent Document 1, since the separability between the solution part and the non-solution part is improved when the gravity sedimentation method is carried out, coal components soluble in the solvent remain in the non-solution part, Insoluble ash can be prevented from remaining in the solution part, and the yield of ashless coal is improved correspondingly. However, coal obtained by mixing caking coal with ordinary coal must be used as a raw material.

  On the other hand, when producing ashless coal in the coal production area, there is no room for selecting various types of raw material (coal). That is, when producing ashless coal in the coal production region, as described in Patent Document 1, it is difficult to mix caking coal with general coal.

  The “yield” in the present application is, for example, the ratio of the mass of ashless coal produced to the mass of coal as a raw material, and may be referred to as “production efficiency”. For example, in the case of a raw material (coal) containing many coal components soluble in a solvent, the “yield” is increased. The “yield” is also increased in the case of a raw material (coal) having a small amount of ash insoluble in the solvent.

  The present invention has been made in view of the above circumstances, and its purpose is to produce ashless coal in a coal production area where there is no room for selecting various types of raw material (coal). It is providing the manufacturing method of ashless coal which can improve the yield of ashless coal.

  The present invention includes a raw material separation step of separating coal according to a predetermined particle size, an extraction step of extracting a coal component soluble in a solvent by heating a slurry obtained by mixing coal and a solvent, and the extraction step. A separation step of separating the solution portion containing the coal component from the slurry from which the coal component has been extracted, and an ashless coal acquisition step of obtaining ashless coal by evaporating and separating the solvent from the solution portion separated in the separation step And a method for producing ashless coal. The method for producing ashless coal has a raw material analysis stage for analyzing the properties of coal according to a predetermined particle size, and uses the coal in a predetermined particle size range determined based on the analysis result of the raw material analysis stage, In the raw material separation step, coal is classified according to particle size.

  According to the present invention, the yield of ashless coal can be improved even when ashless coal is produced in a coal production area where there is no room for various types of raw material (coal) to be selected. Note that the caking coal described in Patent Document 1 is more expensive than steam coal. According to the present invention, the yield of ashless coal can be improved without using expensive caking coal.

It is a block diagram which shows the ashless coal manufacturing equipment for demonstrating the manufacturing method of the ashless coal of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ashless coal production facility 100 includes a coal hopper 1, a solvent tank 2, a slurry preparation tank 3, a transfer pump 4, a preheater 5, in order from the upstream side of the ashless coal (HPC) production process. An extraction tank 6, a gravity sedimentation tank 7, a filter unit 8, and a solvent separator 9 are provided. Further, on the downstream side of the weight settling tank 7, a solvent insoluble component concentrate (solid insoluble component concentrate) for obtaining a by-product charcoal by evaporating and separating the solvent from the solvent insoluble component concentrate (solid content concentrate) separated in the separation step. A solvent separator (for separating and recovering the solvent from the solid content concentrate) is disposed.

  Here, the manufacturing method of ashless coal of this embodiment has a raw material analysis stage, a raw material separation process, an extraction process, a separation process, and an ashless coal acquisition process. Hereinafter, the raw material analysis stage and each process will be described.

(Raw material analysis stage)
The raw material analysis step is a step of performing a property analysis of coal according to a predetermined particle size and a property analysis of coal that is not divided according to particle size. If necessary, raw material analysis is performed after pulverizing coal.

  Examples of coal property analysis include analysis of the proportion of coal components soluble in the solvent used (hereinafter referred to as “extraction rate”), analysis of the ash content of the raw material (coal), and the like. The yield of ashless coal is improved by using coal with a high extraction rate as the raw material. Moreover, the yield of ashless coal will improve if the coal of the particle size range with a low ash content is used as a raw material. In addition, the property analysis of coal should just be the property analysis which contributes to the improvement of the yield of ashless coal, and is not restricted to an extraction rate analysis and an analysis of ash content. The extraction rate is one of the performances of coal, and the ash concentration is one of the components of coal.

  When analyzing the extraction rate as a property analysis of coal, the raw material analysis stage is a step in which basic data on the relationship between the extraction rate and the coal particle size is acquired in advance for the raw material (coal). When analyzing the ash concentration as an analysis, the raw material analysis stage is a stage in which basic data on the relationship between the ash concentration and the coal particle size is acquired in advance for the raw material (coal). The data shown in Table 1 shown below is an example of basic data.

  Based on the analysis result (basic data) obtained in the raw material analysis stage, the particle size range of coal to be input from the coal hopper 1 to the slurry preparation tank 3 is determined. For example, by comparing the results of the analysis of the properties of each coal classified according to a predetermined particle size with the results of the properties analysis of the coal that has not been classified according to particle size, that is, as-is, the coal that has not been classified Rather than the yield of ashless coal when producing ashless coal as a raw material, ashless when producing ashless coal using coal of a predetermined particle size range obtained by fractionation as a raw material The particle size range of coal to be charged into the slurry preparation tank 3 is determined (finds) so that the yield of charcoal is higher.

  In determining the particle size range of the coal to be charged into the slurry preparation tank 3, as described above, in order to improve the yield of ashless coal more reliably, as a comparison target, fractionation is not performed (separated by particle size). None) It is preferable to analyze the properties of coal, but it is not essential to analyze the properties of coal that has not been fractionated. As shown in the examples described later, if the particle size of the raw material (coal) is different, the extraction rate, the ash concentration, and the like are also different. Therefore, only the property analysis of each coal classified according to the predetermined particle size is performed, and based on the result, for example, if the coal with the highest extraction rate is used as the raw material, the coal not divided according to the particle size is used as the raw material. As a result, the yield of ashless coal is improved.

  In addition, although an extraction process, a separation process, and an ashless coal acquisition process are a series of continuous processes performed each time, this raw material analysis stage does not need to be performed as a series of continuous processes performed each time. For example, the raw material analysis step may be performed at least once when the same raw material (coal) is continuously used in the production of ashless coal.

  In addition, the analysis of the extraction rate in the raw material analysis stage uses the solvent used in the extraction step (solvent soluble component extraction step) described later, and the heating temperature and pressure are the same conditions as in the solvent soluble component extraction step. Set the conditions.

  Further, in the raw material analysis stage, the predetermined particle size may be appropriately set according to the particle size distribution of the entire raw coal, etc., and the predetermined particle size region can be determined by repeating the analysis a plurality of times while changing the particle size range. .

  There is no restriction | limiting in particular in the coal used as a raw material, Bituminous coal with a high extraction rate (ashless coal recovery rate) may be used, and cheaper inferior quality coal (subbituminous coal, lignite) may be used.

(Raw material separation process)
The raw material separation step is a step of separating coal according to a predetermined particle size. Specific examples include sieving. As described above, based on the analysis result (basic data) obtained in the raw material analysis stage, the particle size range of coal to be charged into the slurry preparation tank 3 is determined (found). In the raw material separation step, the coal is separated so that the coal in the determined (found) particle size range is input from the coal hopper 1 to the slurry preparation tank 3 (so as to be used as a raw material). For example, a sieve (not shown) is installed between the coal hopper 1 and the slurry preparation tank 3, and the coal is sieved so that coal in the determined particle size range is put into the slurry preparation tank 3. In the raw material fractionation step, the coal is fractionated so that coal in a particle size range with a low yield (for example, a low extraction rate) is excluded from the raw material. If necessary, the raw materials are separated after pulverizing the coal.

  Note that a sieve (not shown) may be installed upstream of the coal hopper 1, and the coal may be sieved so that coal in the determined particle size range is input to the coal hopper 1.

(Extraction process)
An extraction process is a process of extracting the coal component soluble in a solvent by heating the slurry obtained by mixing coal and a solvent. In this embodiment, this extraction step includes a slurry preparation step for preparing a slurry by mixing coal and a solvent, and a solvent for extracting a coal component soluble in the solvent by heating the slurry obtained in the slurry preparation step. It is divided into the soluble component extraction process.

  When extracting coal components that are soluble in the solvent by heating the slurry obtained by mixing coal and solvent, a solvent with a large dissolving power for coal, often an aromatic solvent (hydrogen donating property) Or a non-hydrogen-donating solvent) and coal are mixed and heated to extract organic components in the coal.

The non-hydrogen donating solvent is a coal derivative which is a solvent mainly composed of a bicyclic aromatic and purified mainly from a coal carbonization product. This non-hydrogen-donating solvent is stable even in a heated state and has excellent affinity with coal. Therefore, the proportion of soluble components (herein, coal components) extracted into the solvent (hereinafter also referred to as extraction rate) In addition, it is a solvent that can be easily recovered by a method such as distillation. Main components of the non-hydrogen donating solvent include bicyclic aromatic naphthalene, methyl naphthalene, dimethyl naphthalene, trimethyl naphthalene and the like, and other non-hydrogen donating solvent components have aliphatic side chains. Naphthalenes, anthracenes, fluorenes, and these include biphenyl and alkylbenzenes having long aliphatic side chains.
In the above description, the case where a non-hydrogen donating compound is used as a solvent has been described, but it is needless to say that a hydrogen donating compound (including coal liquefied oil) typified by tetralin may be used as a solvent. . When a hydrogen donating solvent is used, the yield of ashless coal is improved.

  Further, the boiling point of the solvent is not particularly limited. From the viewpoint of pressure reduction in the extraction step and separation step, extraction rate in the extraction step, solvent recovery rate in the ashless coal acquisition step, etc., for example, a solvent having a boiling point of 180 to 300 ° C., particularly 240 to 280 ° C. Preferably used.

<Slurry preparation process>
The slurry preparation step is performed in the slurry preparation tank 3 in FIG. Coal having a predetermined particle size range is input from the coal hopper 1 to the slurry preparation tank 3, and the solvent is input from the solvent tank 2 to the slurry preparation tank 3. The coal and the solvent charged into the slurry preparation tank 3 are mixed by the stirrer 3a to become a slurry composed of coal and a solvent having a predetermined particle size range.

  The mixing ratio of coal with respect to the solvent is, for example, 10 to 50% by weight on the basis of dry coal, and more preferably 20 to 35% by weight.

<Solvent soluble component extraction process>
The solvent-soluble component extraction step is performed in the preheater 5 and the extraction tank 6 in FIG. The slurry prepared in the slurry preparation tank 3 is once supplied to the preheater 5 by the transfer pump 4 and heated to a predetermined temperature, then supplied to the extraction tank 6, and stirred at the predetermined temperature while being stirred by the stirrer 6a. It is retained and extracted.

  The heating temperature of the slurry in the solvent-soluble component extraction step is not particularly limited as long as the solvent-soluble component can be dissolved. From the viewpoint of sufficient dissolution of the solvent-soluble component and improvement of the extraction rate, for example, 300 to 420 It is 360 degreeC, More preferably, it is 360-400 degreeC.

  Also, the heating time (extraction time) is not particularly limited, but is, for example, 10 to 60 minutes from the viewpoint of sufficient dissolution and improvement of the extraction rate. The heating time is the total heating time in the preheater 5 and the extraction tank 6 in FIG.

  The solvent-soluble component extraction step is performed in the presence of an inert gas such as nitrogen. The pressure in the extraction tank 6 is preferably 1.0 to 2.0 MPa, although it depends on the temperature at the time of extraction and the vapor pressure of the solvent used. When the pressure in the extraction tank 6 is lower than the vapor pressure of the solvent, the solvent volatilizes and is not confined in the liquid phase, so that extraction cannot be performed. In order to confine the solvent in the liquid phase, a pressure higher than the vapor pressure of the solvent is required. On the other hand, if the pressure is too high, the cost of the equipment and the operating cost increase, which is not economical.

  As in this embodiment, after mixing coal and solvent, the obtained slurry is not heated to extract coal components soluble in the solvent, but only the solvent is heated first and heated. Alternatively, coal may be supplied into a solvent at a high temperature (for example, 380 ° C.) (supplied in a dry state), the coal may be mixed and heated, and solvent-soluble components in the coal may be extracted with the solvent.

  As a method of heating only the solvent first and supplying coal into the heated high-temperature (for example, 380 ° C.) solvent (supplying in a dry state), for example, the following methods are available. The coal hopper 1 is not arranged on the upstream side of the transfer pump 4, so that the coal can be directly supplied into the pipe 24 connecting the preheater 5 and the extraction tank 6 or into the extraction tank 6. Place. At this time, for example, the connection portion between the pipe 24 or the extraction tank 6 and the coal hopper 1 is pressurized with an inert gas such as nitrogen so that the solvent does not flow back into the coal hopper 1. According to this method, it is necessary to pressurize the connecting portion between the pipe 24 or the extraction tank 6 and the coal hopper 1 with an inert gas such as nitrogen so that the solvent does not flow back into the coal hopper 1. However, the slurry preparation tank 3 can be omitted.

(Separation process)
The separation step is a step of separating the solution portion containing the coal component dissolved in the solvent from the slurry from which the coal component has been extracted in the extraction step. In other words, in the separation step, the slurry from which the coal component is extracted in the extraction step is divided into a solution portion containing the coal component dissolved in the solvent, and a solvent-insoluble component concentrate (also referred to as a solid content concentrate). It is a process of separating. This separation step is performed in the gravity settling tank 7 in FIG. The slurry from which the coal component has been extracted in the extraction step is separated into a supernatant liquid as a solution part and a solid content concentrate by gravity in the gravity sedimentation tank 7 (gravity sedimentation method). The supernatant liquid in the upper part of the gravity settling tank 7 is discharged to the solvent separator 9 through the filter unit 8 as necessary, and the solid concentrate settled in the lower part of the gravity settling tank 7 is sent to the solvent separator 10. Discharged.

  The gravitational sedimentation method is a method in which a slurry is retained in a tank to settle and separate solvent-insoluble components using gravity. A continuous separation process is possible by continuously discharging the supernatant from the top and the solid concentrate from the bottom while continuously supplying the slurry into the tank.

  The gravity settling tank 7 is preferably heated or / and pressurized in order to prevent reprecipitation of solvent-soluble components eluted from coal. The heating temperature is, for example, 300 to 370 ° C., and the tank internal pressure is, for example, 1.0 to 2.0 MPa.

  As a method for separating the solution portion containing the coal component dissolved in the solvent from the slurry from which the coal component has been extracted in the extraction step, there are a filtration method, a centrifugal separation method, and the like in addition to the gravity sedimentation method.

(Ashless coal acquisition process)
The ashless coal acquisition step is a step of obtaining ashless coal by evaporating and separating the solvent from the solution part separated in the separation step. This ashless charcoal acquisition process is performed by the solvent separator 9 in FIG.

  As a method for separating the solvent from the solution part (supernatant liquid), a general distillation method or an evaporation method can be used, and the separated and recovered solvent can be circulated to the slurry preparation tank 3 and repeatedly used. . By separating and collecting the solvent, ashless coal (HPC) substantially free of ash can be obtained from the supernatant. Ashless coal contains almost no ash, has no moisture, and exhibits a higher calorific value than raw coal. Furthermore, the softening and melting property, which is a particularly important quality as a raw material for coke for iron making, has been greatly improved, and the obtained ashless coal (HPC) has good softening and melting properties even if the raw material coal does not have softening and melting properties. Have Therefore, ashless coal can be used, for example, as a blended coal for coke raw materials.

(By-product coal acquisition process)
The byproduct charcoal acquisition step is a step of obtaining byproduct charcoal by evaporating and separating the solvent from the solvent-insoluble component concentrate (solid content concentrate) separated in the separation step. This byproduct charcoal acquisition process is also a process for evaporating and recovering the solvent from the solvent-insoluble component concentrate (solid content concentrate), and is performed by the solvent separator 10 in FIG. In addition, a byproduct charcoal acquisition process is not an essential process.

  As for the method for separating the solvent from the solvent-insoluble component concentrate (solid content concentrate), a general distillation method or evaporation method can be used as in the above-described ashless coal acquisition step, and the solvent is separated and recovered. The solvent can be circulated to the slurry preparation tank 3 and used repeatedly. By separation and recovery of the solvent, by-product coal (also referred to as RC or residual coal) in which solvent-insoluble components including ash and the like are concentrated can be obtained from the solid concentrate. By-product charcoal contains ash, but has no water and has a sufficient calorific value. By-product coal does not exhibit softening and melting properties, but the oxygen-containing functional groups are eliminated, so that when used as a blended coal, it inhibits the softening and melting properties of other coals contained in this blended coal. It is not a thing. Therefore, this by-product coal can be used as a part of the blended coal of the coke raw material, as in the case of ordinary non-slightly caking coal, and is used for various fuels without using the coke raw coal. It is also possible. The by-product coal may be discarded without being collected.

(Example)
The bituminous coal used as the raw coal was classified by particle size (1.0 mm, 2.0 mm, 3.0 mm, 4.75 mm) without being pulverized, and the properties of the raw coal were analyzed. The properties of raw coals that were not sorted by particle size (as they were) were also analyzed. Specifically, a raw material coal for each particle size and a raw material coal not subjected to separation (sieving) (as it is) are mixed with a solvent to prepare a slurry, and the prepared slurry is 2.0 MPa. Nitrogen was applied under pressure, and an extraction treatment was performed in an autoclave at 400 ° C. for 20 minutes, and the extraction rate and ash concentration were measured. The results are shown in Table 1. The data shown in Table 1 is an example of basic data in the present invention, which shows the relationship between the extraction rate, ash concentration, and coal particle size.

  In addition, the bituminous coal used as coking coal is a general coal used for a power generation use, and is classified into Category C in Japanese coal classification method (JIS M1002-1978).

  As shown in Table 1, the extraction rate (ratio of coal components soluble in the solvent) of 54.1% by weight was shown for the raw coal that was not sieved (as it was). daf (dry ash free) means anhydrous ashless. The extraction rate showed anhydrous ashless coal, that is, the ratio of extracted organic component to organic component.

On the other hand, the raw coal having a particle size of 1.0 mm or less showed an extraction rate of 49.5% by weight daf, which was lower than the extraction rate of the raw coal without sieving (as it was). On the other hand, the raw coal having a particle size of more than 3.0 mm and not more than 4.75 mm showed an extraction rate of 58.2% by weight daf higher than the extraction rate of the raw coal without sieving (as it is). Thus, it can be seen that the extraction rate varies depending on the particle size. This is not limited to bituminous coal, but also applies to other types of coal.

  In addition, the raw coal with a particle size of 1.0 mm or less is a raw coal that has passed through a sieve having an opening of 1.0 mm, and the raw coal with a particle size of more than 3.0 mm and 4.75 mm or less It refers to raw coal that does not pass through a sieve with an opening of 3.0 mm and passes through a sieve with an opening of 4.75 mm. The same applies to the raw coals of other particle sizes shown in Table 1.

  In the case of the raw coal of this example, for example, the raw coal with a particle size of 2.0 mm or less is screened and removed, and the extraction step, the separation step, and the When the ash coal acquisition process is performed, the extraction rate calculated from Table 1 is 55.6% by weight daf, which is 1.5 wt. Than when raw coal is used as it is without sieving (as is). The extraction rate can be improved by about% daf. Thus, the extraction rate can be improved by using coal having a particle size range that is higher than the extraction rate of coal when sieving is not performed among the screened coals. . That is, the yield of ashless coal can be improved. In addition, the coal of the particle size range which showed the low extraction rate can be efficiently used as a whole by using it as a fuel for power generation. In addition, the coking coal having a particle size of 1.0 mm or less is simply removed by sieving, and the above-described extraction process, separation process, and ashless coal acquisition process are performed using the coking coal having a particle size exceeding 1.0 mm. May be.

  Moreover, as shown in Table 1, the ash content concentration of 11.3 wt% was shown for the raw coal that was not sieved (as it was). On the other hand, the raw coal having a particle size exceeding 4.75 mm showed an ash concentration of 14.4% by weight, which was higher than the ash concentration of the raw coal without sieving (as it was). On the other hand, the raw coal having a particle size of more than 1.0 mm and not more than 2.0 mm showed an ash concentration of 8.98% by weight, which is lower than the ash concentration of raw coal without sieving (as it is). Thus, it can be seen that the ash concentration varies depending on the particle size. This is not limited to bituminous coal, but also applies to other types of coal.

  In the case of the raw coal of the present example, for example, the raw coal having a particle size exceeding 4.75 mm is removed by sieving to obtain a raw coal having a particle size of 4.75 mm or less. The ash concentration contained in the charcoal is 9.15% by weight, which is a raw material having an ash concentration of 2.15% by weight lower than that of raw coal that is not sieved (as is). When this extraction coal, the above-described extraction step, separation step, and ashless coal acquisition step are carried out, the amount of ash contained in the raw coal is small, so the raw coal that has not been sieved (as it is) is used as raw material Thus, the yield of ashless coal can be improved. By sieving and using raw coal with a low ash concentration, there is also an effect that the amount of ash to be input to the above-described series of processing steps for obtaining ashless coal can be reduced.

  Thus, among sieved coal, the yield of ashless coal is improved by using coal having a particle size range having an ash concentration lower than the ash concentration of coal when sieving is not performed. In addition, it is possible to reduce the amount of ash input to the above series of processing steps for obtaining ashless coal.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. .

1: Coal hopper 2: Solvent tank 3: Slurry preparation tank 4: Transfer pump 5: Preheater 6: Extraction tank 7: Gravity settling tank 8: Filter unit 9, 10: Solvent separator 100: Ashless coal production equipment

Claims (4)

A raw material separation step of separating coal according to a predetermined particle size;
An extraction step of heating a slurry obtained by mixing coal and a solvent to extract a coal component soluble in the solvent;
A separation step of separating the solution portion containing the coal component from the slurry from which the coal component has been extracted in the extraction step;
Ashless coal acquisition step for obtaining ashless coal by evaporating and separating the solvent from the solution portion separated in the separation step;
In a method for producing ashless coal,
It has a raw material analysis stage to analyze the properties of coal according to a predetermined particle size,
The ashless coal is characterized in that coal is classified according to particle size in the raw material separation step so that the extraction step is performed using coal of a predetermined particle size range determined based on the analysis result of the raw material analysis stage. Production method. In the manufacturing method of ashless coal of Claim 1,
Further analysis of the properties of coal not divided according to particle size is performed in the raw material analysis stage,
The result of the property analysis of coal according to a predetermined particle size is compared with the result of the property analysis of coal not divided according to particle size to determine the particle size range, and the extraction step is performed using coal in the particle size range A method for producing ashless coal, characterized in that In the manufacturing method of the ashless coal of Claim 2,
Among the coals separated in the raw material separation step, the extraction step is performed using coal in the particle size region that has a higher extraction rate of the coal component as a whole than the extraction rate of the coal component when not classified according to particle size. A method for producing ashless charcoal, characterized in that it is performed. In the manufacturing method of the ashless coal in any one of Claims 1-3,
In the raw material analysis stage, for coal, the basic data on the relationship between the extraction rate of the coal component and the particle size of the coal is acquired in advance, and the extraction rate of the coal component is increased based on the basic data. A method for producing ashless coal, characterized in that, in the raw material fractionation step, fractionation is performed so as to use the found coal having a predetermined particle size as a raw material.

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