JP5314299B2 - Production method of ashless coal - Google Patents

Description

  The present invention relates to a method for producing ashless coal used as a raw material for carbon materials constituting structural materials and electrical materials.

  Conventionally, carbon materials have been widely used as structural materials and electrical materials because of their excellent heat resistance and chemical stability and electrical conductivity. Further, since carbon exhibits an action of reducing many metal oxides at a high temperature, it is also used as a reducing agent in refining silicon and titanium. The characteristics required of carbon materials vary depending on the application. However, the less impurities (called ash) other than carbon, the more the characteristics of carbon materials are deteriorated and the sources of contamination are. Good. In particular, when it is used as a metallurgical reducing agent, it is required to have a low ash content.

  As raw materials for such a carbon material, coke powder (coal coke or petroleum coke) as an aggregate and tar or pitch as a molding binder are used. Coke is produced by dry distillation of petroleum, characterized by having a low volatile content of 1% by mass, carbonizing without melting, and a high fixed carbon (carbon yield) of about 90% by mass. Tar and pitch are auxiliary materials in the carbonization process, and fixed carbon is not as high as coke, but has a property of melting when heated, and plays a role of connecting coke particles (role of binder). And in the manufacturing process of a carbon material, normally, aggregate components, such as such coke powder, and a binder component are mixed and shape | molded, and it heat-processes to high temperature, and is carbonized.

  Here, for example, coal coke is an unused component when producing iron-making coke, petroleum coke is a by-product of the oil refining process, and tar and pitch are also used in coal and oil refining industry. Is a by-product of As described above, since any of these raw materials is an unused component or a by-product of another manufacturing process, it contains ash in the component (for example, coke contains about 10% by mass of ash). It is inevitable that the carbon material produced using ash also contains ash. However, since this ash content deteriorates the characteristics of the carbon material, it is not preferable to be contained in the component. In addition, since carbonization is a process of heat treatment at a high temperature of 1000 ° C. or higher, a large amount of energy is required, and in the carbon production process, heat treatment at 1000 ° C. or higher is performed again. And is inefficient.

Thus, from the viewpoint of a raw material for a carbon material having a low ash content, so-called ashless coal (hyper coal), which has been actively developed recently, can be cited (for example, see Patent Document 1). Here, ashless coal is produced by extracting coal with a solvent, separating only the components soluble in the solvent, and then removing the solvent. Structurally, this ashless coal has a wide molecular weight distribution from a relatively low molecular weight component having 2 to 3 condensed aromatic rings to a high molecular weight component having about 5 or 6 rings. In addition, since ash is not dissolved in a solvent, ashless coal does not substantially contain ash, exhibits high fluidity under heating, and is excellent in thermal fluidity. Some coals, like caking coal, exhibit thermoplasticity at around 400 ° C., but ashless coal generally melts at 200 to 300 ° C. regardless of the quality of the raw coal. Therefore, taking advantage of this characteristic, application development as a binder component has been advanced, and in recent years, carbon materials can be produced by using this ashless coal as an aggregate component instead of coke. Has been tried.
JP 2001-26791 A

However, the conventional method for producing ashless coal has the following problems.
As described above, the ashless coal produced by the conventional production method generally has a melting temperature of about 200 to 300 ° C., and attempts have been made to use it as an aggregate component and a binder component. .

  Here, when using ashless coal as an aggregate component instead of coke, the melting temperature is generally about 200 to 300 ° C., and, as described above, has a wide molecular weight distribution, Compared with coke, there is a problem that volatile matter is large and fixed carbon (carbon yield) is lowered. On the other hand, when ashless coal is used as a binder component, the softening temperature is higher and the thermal fluidity is lower than that of tar or pitch, so that there is a problem that the function as a binder is not sufficiently exhibited.

  In addition, it is conceivable to manufacture ashless coal for use as an aggregate component and ashless coal for use as a binder component in different processes, while changing the production conditions. Manufacturing in a separate process has a problem that the manufacturing efficiency is low and it is not economical.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is ashless coal having a high softening temperature and capable of improving the carbon yield, and ashless having a low softening temperature and excellent thermal fluidity. It is providing the manufacturing method of ashless coal which can manufacture charcoal simultaneously.

In the method for producing ashless coal according to the present invention, the coal dissolves the first slurry heating step in which the slurry in which coal and the aromatic solvent are mixed is heat-treated, and the slurry heat-treated in the first slurry heating step. The liquid component and the solid component containing ash and insoluble coal are separated into a first separation step, and the solid component separated in the first separation step is added and mixed, and the mixed slurry is mixed. The second slurry heating step for heat treatment at a temperature higher than the heat treatment in the first slurry heating step; the slurry heat-treated in the second slurry heating step; the liquid component in which coal is dissolved; the ash content and the insolubility a second separation step of separating the, and a solid component containing coal, comprising a modified coal obtaining step of obtaining the ashless coal which is modified coal, and the upgraded coal acquisition step, before Symbol first separation Separated in the process From the liquid component by removing the aromatic solvent, the first ash-free coal obtaining step of obtaining the ashless coal which is modified coal, aromatic solvent is removed from the liquid component separated in the second separation step And a second ashless coal acquisition step of acquiring ashless coal which is reformed coal .

  According to such a manufacturing method, in the first slurry heating step, the slurry is heat-treated at a temperature lower than the heat treatment in the second slurry heating step, and the coal component is heated and extracted into the aromatic solvent. From the extracted liquid component, ashless coal with a low softening temperature (hereinafter, referred to as first ashless coal as appropriate) is produced. Further, in the second slurry heating step, the slurry obtained by adding and mixing the aromatic solvent to the solid component separated in the first separation step is heat-treated at a temperature higher than the heat treatment in the first slurry heating step, and the coal component Is extracted into an aromatic solvent to produce ashless coal having a high softening temperature (hereinafter, referred to as second ashless coal as appropriate) from the liquid component extracted by heating.

Method for producing ashless coal according to the present invention, the modified coal acquisition step, obtaining the ashless coal from a liquid component separated in the first liquid component separated in the separation step and the second separation step in addition to, in the et, to include the second and from the separated solid component in the separation step removing the aromatic solvent, residue coal obtaining step of obtaining a residue coal which is modified coal Features.
According to such a manufacturing method, the by-product by manufacture of ashless coal can be utilized as by-product coal, and an aromatic solvent can be collect | recovered.

According to the method for producing ashless coal according to the present invention, ashless coal for use as an aggregate component, which has a high softening temperature and can improve carbon yield, is produced with high efficiency and at low cost. be able to. In addition, ashless coal having a low softening temperature and excellent thermal fluidity for use as a binder component can be produced with high efficiency and at low cost. And since these two types of ashless coal can be manufactured simultaneously, manufacture of ashless coal can be performed still more efficiently and cheaply.
Furthermore, in addition to ashless coal, by-product coal can be produced with high efficiency and at low cost.

  Next, a method for producing ashless coal according to the present invention will be described in detail with reference to the drawings. In the drawings to be referred to, FIG. 1 is a flowchart for explaining the steps of the method for producing ashless coal, FIG. 2 is a schematic diagram showing an outline of the method for producing ashless coal, and FIG. It is a schematic diagram which shows the solid-liquid separation apparatus for this.

≪Production method of ashless coal≫
As shown in FIGS. 1 and 2, the method for producing ashless coal includes a first slurry heating step (S1), a first separation step (S2), a second slurry heating step (S3), and a second separation step. (S4) and a modified coal acquisition process (S5) are included.
Hereinafter, each step will be described.

<First slurry heating step (S1)>
The first slurry heating step (S1) is a step of preparing a slurry by mixing coal and an aromatic solvent, and heat-treating the slurry containing the coal and the aromatic solvent (first slurry heating treatment). And a coal component is heat-extracted by the aromatic solvent by heat-processing a slurry.

  Coal to be used as raw material (hereinafter also referred to as “raw coal”) should be non-slightly caking coal that has little softening and melting properties, or low quality coal such as lignite or sub-bituminous coal. Is preferred. By using inexpensive coal such as these, ashless coal can be produced at a lower cost, so that economic efficiency can be improved. However, the coal used is not limited to these inferior coals, and bituminous coals may be used.

  In addition, inferior coal here means coals, such as a non-slightly caking coal, a general coal, and a low grade coal. The low-grade coal is coal that contains 20% by mass or more of water and is desired to be dehydrated. Examples of such low-grade coal include lignite, lignite, and sub-bituminous coal. For example, lignite coal includes Victoria coal, North Dakota coal, Belga coal, etc., and sub-bituminous coal includes West Banco coal, Binungan coal, Samarangau coal, and the like. The low-grade coal is not limited to those exemplified above, and any coal containing a large amount of water and desired to be dehydrated is included in the low-grade coal referred to in the present invention.

  Generally, aromatic solvents that dissolve coal include monocyclic aromatic compounds such as benzene, toluene, and xylene, and bicyclic aromatic compounds such as naphthalene, methylnaphthalene, dimethylnaphthalene, and trimethylnaphthalene. . The bicyclic aromatic compound includes other naphthalenes having an aliphatic side chain, and biphenyl and alkylbenzene having a long aliphatic side chain. A bicyclic aromatic compound which is a non-hydrogen donating solvent is preferable.

  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. Since this non-hydrogen donating solvent is stable even in a heated state and has excellent affinity with coal, the proportion of coal components extracted into the solvent (hereinafter also referred to as “extraction rate”) is high. It is a solvent that can be easily recovered by methods such as distillation. The recovered solvent can be circulated and used repeatedly in order to improve economy.

  The aromatic solvent preferably has a boiling point of 180 to 330 ° C. When the boiling point is less than 180 ° C., the required pressure in the heat extraction or in the first separation step (S2) and the second separation step (S4) described later increases, and the step of recovering the aromatic solvent Therefore, the loss due to volatilization increases, and the recovery rate of the aromatic solvent decreases. Furthermore, the extraction rate in the heat extraction decreases. On the other hand, when it exceeds 330 ° C., it becomes difficult to separate the aromatic solvent from the liquid component or the solid component in the modified coal acquisition step (S5), and the solvent recovery rate is reduced.

Although the coal density | concentration with respect to an aromatic solvent is based also on the kind of raw material coal, the range of 10-50 mass% is preferable on a dry coal basis, and the range of 20-35 mass% is more preferable. When the coal concentration with respect to the aromatic solvent is less than 10% by mass, the proportion of the coal component extracted into the aromatic solvent is less than the amount of the aromatic solvent, which is not economical. On the other hand, the higher the coal concentration is, the more preferable, but when it exceeds 50% by mass, the viscosity of the slurry becomes high, and the liquid component and the solid component in the movement of the slurry and the first separation step (S2) and the second separation step (S4). It tends to be difficult to separate them.
In addition, it is the same as that of the above also about the density | concentration of the solid component with respect to the aromatic solvent in the 2nd slurry heating process (S3) mentioned later.

  The slurry heat treatment (heat extraction) in the first slurry heating step (S1) is performed at a relatively low temperature. As is well known, the solvent power tends to increase with increasing temperature. Therefore, in the first slurry heating step (S1), a component that is relatively easily dissolved in coal by heat treatment at a relatively low temperature, that is, a component that has a relatively low molecular weight and consequently melts at a relatively low temperature. Is extracted. Therefore, the ashless coal obtained in the first slurry heating step (S1) exhibits a relatively low softening temperature. Note that “the softening temperature is low” means that the general softening temperature of ashless coal is about 200 to 300 ° C., and is here about 200 ° C. or less.

  The heating temperature is not particularly limited as long as it is relatively low, but it is preferably performed at a temperature of 250 to 350 ° C. This temperature range can generally be said to be relatively low in solvent extraction. By setting the heating temperature within this range, ashless coal having a low softening temperature can be obtained in a modified coal acquisition step (S5) described later while securing an appropriate extraction rate.

When the heating temperature of the slurry is 250 ° C. or higher, the amount of the low molecular weight component separated in the first slurry heating step (S1) increases, and the component that melts at a relatively low temperature is sufficiently extracted. In the step (S3), since the ratio of extracting this component decreases, the softening temperature of the second ashless coal becomes sufficiently high. Further, the extraction rate of the first ashless coal (the yield of ashless coal) is not too low (for example, less than 15% by mass). On the other hand, if it is 350 ° C. or lower, components that melt at a relatively high temperature are not extracted, so the softening temperature of the first ashless coal does not increase, and the extraction rate in the first slurry heating step (S1) is high. Since it does not become too much, the extraction rate (yield) of the second ashless coal is not too low (for example, less than 15% by mass). In order to lower the softening temperature of ashless coal while securing a more appropriate extraction rate, the temperature is preferably 300 to 320 ° C.
However, the above-mentioned heating temperature is a guideline and is appropriately adjusted depending on the type of coal or solvent used, the properties of the desired product, and the like.

Here, the extraction rate (the yield of ashless coal) in the first slurry heating step (S1) is the total ashless coal yield (the yield of the first ashless coal + the yield of the second ashless coal). (For example, if the total ashless coal yield is 60 mass%, the yield of the first ashless coal is 18 to 42 mass% (coal basis)). As a guide).
In addition, the desired yield and softening temperature in the first ashless coal are a standard, and vary depending on the type of coal and solvent used, the properties of the desired product, and the like.

  The heating time (extraction time) is a criterion for reaching the dissolution equilibrium, but it is economically disadvantageous to realize it. Therefore, since it varies depending on conditions such as the particle size of the coal, the type of solvent, etc., it cannot be generally stated, but it usually takes about 10 to 60 minutes after passing through a preheater and reaching a predetermined extraction temperature. If the heating time is less than 10 minutes, the extraction of the coal component tends to be insufficient, while if it exceeds 60 minutes, the extraction does not proceed any further, which is not economical. In addition, before the transition to the first separation step (S2), the heated slurry may be cooled to a temperature at which the solute eluted from the coal does not reprecipitate, for example, 150 ° C. or more and less than about 200 ° C. Good. By cooling the slurry, subsequent handling is facilitated, and excessive thermal decomposition in the first slurry heating step (S1) can be avoided. In addition, the pressure in the sedimentation tank can be lowered, and the specification level of valves and the like can be lowered.

  In this heating extraction, the coal is thermally decomposed to produce aromatic-rich components mainly having an average boiling point (Tb50: 50% distillation temperature) of 200 to 300 ° C. Can be used as part.

  Heat extraction is preferably performed in a non-reducing atmosphere. Specifically, it is performed in the presence of an inert gas. This is because contact with oxygen during heating extraction is dangerous because it may ignite, and the cost increases when hydrogen is used.

  As the inert gas used in the heat extraction, inexpensive nitrogen is preferably used, but is not particularly limited. The pressure in the heat extraction is preferably 1.0 to 2.0 MPa, although it depends on the temperature at the time of heat extraction and the vapor pressure of the aromatic solvent used. When the pressure is lower than the vapor pressure of the aromatic solvent, the aromatic solvent volatilizes and is not trapped in the liquid phase and cannot be extracted. In order to confine the aromatic solvent in the liquid phase, a pressure higher than the vapor pressure of the aromatic 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.

<First separation step (S2)>
The first separation step (S2) is a step of separating the slurry heated in the first slurry heating step (S1) into a liquid component and a solid component (first slurry separation).
Here, the liquid component means a solution in which coal is dissolved, that is, a solution containing a coal component dissolved (extracted) in an aromatic solvent, and the solid component means ash and insoluble coal insoluble in the aromatic solvent. A slurry containing

  Although it does not specifically limit as a method of isolate | separating a slurry into a liquid component and a solid component at a 1st isolation | separation process (S2), It is preferable to use a gravity sedimentation method.

  As a method for separating a slurry into a liquid component and a solid component, various filtration methods and centrifugal separation methods are generally known. However, the filtration method requires frequent replacement of the filter, and the centrifugation method tends to cause clogging with undissolved coal components, and it is not easy to implement these methods industrially. Therefore, it is preferable to use a gravity sedimentation method that allows continuous operation of fluid and is suitable for a large amount of processing at low cost. Thus, from the upper part of the gravity sedimentation tank, the liquid component (hereinafter also referred to as “supernatant liquid”), which is a solution containing the coal component extracted into the aromatic solvent, is transferred to the aromatic solvent from the lower part of the gravity sedimentation tank. A solid component (hereinafter also referred to as “solid content concentrate”) that is a slurry containing insoluble ash and insoluble coal can be obtained. Note that the gravity sedimentation method is one of the options, and other methods may be used.

Hereinafter, an example of the gravity sedimentation method will be described with reference to FIGS.
As shown in FIG. 3, in the gravity sedimentation method, in the solid-liquid separation device 100, first, powder coal as a raw material and an aromatic solvent are mixed in a coal slurry preparation tank 1 to prepare a slurry. Next, a predetermined amount of slurry is supplied from the coal slurry preparation tank 1 to the preheater 3 by the pump 2, and the slurry is heated to 250 to 350 ° C. And the heated slurry is supplied to the extraction tank (extractor) 4, and it heats for 10 to 60 minutes at 250-350 degreeC, stirring with the stirrer 10 (1st slurry heating process (S1)). After heating, the cooler 7 may immediately cool to 150 ° C. or higher and lower than 200 ° C. as necessary. Note that a cooling mechanism may be provided in the extraction tank 4 in order to cool the slurry. And the slurry which performed this extraction process is supplied to the gravity sedimentation tank 5, and a slurry is isolate | separated into a supernatant liquid and a solid content concentrate (1st separation process (S2)), and the gravity sedimentation tank 5 is made into the lower part. The settled solid content concentrate is discharged to the solid content receiver 6 and the upper supernatant is discharged to the filter unit 8 by a predetermined amount.

  Here, in the gravity settling tank 5, in order to prevent reprecipitation of the solute eluted from the raw material coal, when the slurry is heated, and when the slurry is cooled after being cooled, the temperature is maintained after being heated. The pressure is preferably in the range of 1.0 to 2.0 MPa. Further, in the gravity settling tank 5, the time for maintaining at a predetermined temperature is the time required to separate the slurry into a supernatant and a solid concentrate, and is generally 60 to 120 minutes. It is not particularly limited.

It should be noted that by increasing the number of gravity sedimentation tanks 5, it is possible to recover components that are soluble in the aromatic solvent accompanying the solid concentration liquid. It is appropriate to arrange in steps.
And the supernatant liquid discharged | emitted from the gravity sedimentation tank 5 is filtered by the filter unit 8 as needed, and is collect | recovered by the supernatant liquid receiver 9. FIG.

Then, as will be described below, this solid component is supplied to the second slurry heating step (S3), and after the second separation step (S4), the ashless coal (second ashless coal) having a high softening temperature. In addition, the liquid component is separated and recovered using a distillation method or the like to produce ashless coal (first ashless coal) having a low softening temperature (modified coal acquisition step (S5)). )).
If necessary, from the solid component (solid concentration liquid) separated in the second separation step (S4), the aromatic solvent is separated and recovered, and the by-product in which the ash content of the modified coal is concentrated. Charcoal can be obtained. The aromatic solvent separated and recovered from the solid concentrate discharged to the solid concentration receiver 6 and the aromatic solvent separated and recovered from the supernatant recovered in the supernatant receiver 9 are necessary. Accordingly, it is circulated to the coal slurry preparation tank 1 (shown by a dotted line portion in FIG. 3 for convenience).

<Second slurry heating step (S3)>
In the second slurry heating step (S3), an aromatic solvent is added to and mixed with the solid component separated in the first separation step (S2) to prepare a slurry, and the slurry containing the solid component and the aromatic solvent is prepared. The heat treatment is performed at a temperature higher than the heat treatment in the first slurry heating step (S1) (second slurry heat treatment). And a coal component is heat-extracted by the aromatic solvent by heat-processing a slurry.

  Since the second slurry heating step (S3) is the same as the first slurry heating step (S1) except for the heating temperature in the heat treatment, the heating temperature in the heat treatment will be described here.

  In the second slurry heating step (S3), since the heat treatment is performed at a temperature higher than that in the first slurry heating step (S1), the second slurry heating step (S1) is opposite to the first slurry heating step (S1). In S3), components that are more difficult to dissolve, that is, components that have a relatively high molecular weight and are difficult to melt, are extracted. Therefore, the ashless coal obtained in the second slurry heating step (S3) exhibits a relatively high softening temperature. Note that “the softening temperature is high” means that the softening temperature of general ashless coal is about 200 to 300 ° C., and here, it means about 300 ° C. or higher.

  When the heating temperature in the second slurry heating step (S3) is equal to or lower than the temperature in the heat treatment in the first slurry heating step (S1), the softening temperature does not increase and the extraction rate (yield) is improved. I can't even hope.

  Although it will not specifically limit if the heating temperature in a 2nd slurry heating process (S3) is a temperature higher than the heat processing in a 1st slurry heating process (S1), It is the temperature of 350 to 420 degreeC. It is preferred to do so. By setting the heating temperature within this range, the bonds between the molecules constituting the coal are loosened, mild thermal decomposition occurs, and the extraction rate increases. Moreover, in the modified coal acquisition process (S5) described later, ashless coal having a high softening temperature can be obtained.

  If the heating temperature of the slurry is 350 ° C. or higher, it is sufficient to weaken the bonds between the molecules constituting the coal, and the extraction rate (yield) is likely to improve. Moreover, the softening temperature of the obtained ashless coal tends to be high. On the other hand, when it is 420 ° C. or lower, generation of light components due to thermal decomposition is suppressed, and the softening temperature of the obtained ashless coal is likely to be improved. In addition, the rate of the thermal decomposition / carbonization (polymerization) reaction tends to decrease. As a result, the dissolved component is hardly changed to an insoluble component by the carbonization reaction, and the extraction rate is easily improved. In addition, in order to improve an extraction rate and raise the softening temperature of ashless coal, Preferably it is 380-400 degreeC.

  However, the above-mentioned heating temperature is a guideline and is appropriately adjusted depending on the type of coal or solvent used, the properties of the desired product, and the like. When the heating temperature in the first slurry heating step (S1) is 350 ° C., the heating temperature in the second slurry heating step (S3) is set to a temperature exceeding 350 ° C. Further, the desired yield and softening temperature in the second ashless coal are only a guide, and vary depending on the type of coal and solvent used, the properties of the desired product, and the like.

In addition, before the transition to the second separation step (S4), the heated slurry may be cooled to a temperature at which the solute eluted from the coal does not reprecipitate, for example, about 200 to 360 ° C. By cooling the slurry, subsequent handling is facilitated, and excessive thermal decomposition in the second slurry heating step (S3) can be avoided. In addition, the pressure in the sedimentation tank can be lowered, and the specification level of valves and the like can be lowered.
Other conditions are the same as those in the first slurry heating step (S1).
In addition, although the same solid-liquid separator can be used for both the first slurry heating step (S1) and the second slurry heating step (S3), separate solid-liquid separators may be used.

<Second separation step (S4)>
The second separation step (S4) is a step of separating the slurry heated in the second slurry heating step (S3) into a liquid component and a solid component (second slurry separation).
Since the second separation step (S4) is the same as the first separation step (S2) except for matters relating to temperature control in the gravity sedimentation method, here, matters relating to temperature control in the gravity sedimentation method are described. explain.

An example of the gravity sedimentation method is substantially the same as the first separation step (S2), but in the second separation step (S4), the slurry is heated at 350 to 420 ° C. for 10 to 60 minutes. In addition, you may cool to 200-360 degreeC immediately after heating a slurry. Further, in the gravity settling tank 5, when the slurry is heated, and when the slurry is cooled after being heated, it is preferable to maintain the cooled temperature after the heating, and the pressure is 1.0 to 2.0 MPa. It is preferable to be in the range.
About others, it is the same as that of an example of the gravity sedimentation method in the said 1st separation process (S2).
The same solid-liquid separation device can be used for both the first separation step (S2) and the second separation step (S4), but separate solid-liquid separation devices may be used.

<Modified coal acquisition process (S5)>
In the modified coal acquisition step (S5), the aromatic solvent is removed from the liquid component separated in the second separation step (S4) to acquire ashless coal (second ashless coal) as modified coal. It is a process to do.
Further, in addition to obtaining the second ashless coal, the aromatic solvent is removed from the liquid component separated in the first separation step (S2) to obtain ashless coal (first This is a process for obtaining ash coal.

  As a method for separating and removing the aromatic solvent from the liquid component (supernatant liquid), a general distillation method, an evaporation method (spray drying method, etc.), etc. can be used. It can circulate to the coal slurry preparation tank 1 (refer FIG. 3), and can be used repeatedly. As a result of separation and recovery (solid-liquid separation) of the aromatic solvent, ashless coal having an extremely low ash concentration can be obtained from the supernatant. This ashless coal contains almost no ash, has no moisture, and exhibits performance (thermal fluidity) far superior to that of raw coal.

  And since 1st ashless coal has a low softening temperature and is excellent in heat fluidity, it can be used as a binder component. Therefore, as described later, it can be added to the second ashless coal to improve the moldability of the carbide.

Moreover, since a 2nd ashless coal has a high softening temperature and can improve a carbon yield, it can be used as an aggregate component instead of coke.
And this 2nd ashless coal is carbonized by heat-processing at 1000 degreeC or more in inert gas atmosphere, and a carbide | carbonized_material is manufactured. In addition, the first ashless coal, tar, pitch, or the like may be added to the second ashless coal as a binder component to improve the moldability, and the second ashless coal may be, for example, 350 to 425 ° C. By applying heat treatment for about 30 minutes to 6 hours, self-sintering properties (molding is possible without adding a binder component, and carbonization is carried out while maintaining its shape by heat treatment. Such properties) may be improved.

  If necessary, in the modified coal acquisition step (S5), ashless from the liquid component separated in the first separation step (S2) and the liquid component separated in the second separation step (S4). In addition to obtaining charcoal (first ashless charcoal and second ashless charcoal), the aromatic solvent is removed from the solid component separated in the second separation step (S4), so Raw charcoal may be produced (by-product charcoal acquisition step).

  This by-product charcoal is free of oxygen-containing functional groups, has ash, has no water, and has a sufficient calorific value. Therefore, this byproduct charcoal can be used for various fuels.

  The method for separating and removing the aromatic solvent from the solid component (solid content concentrate) is similar to the above-described modified coal acquisition step (S5) for acquiring ashless coal from the liquid component. The evaporation method can be used, and the aromatic solvent separated and recovered can be circulated to the coal slurry preparation tank 1 (see FIG. 3) and repeatedly used. By separation and recovery (solid-liquid separation) of the aromatic solvent, by-product coal in which ash is concentrated can be obtained from the solid concentrate.

By the way, only ashless coal without ash is produced from the liquid component separated in the second separation step (S4) as a raw material for the carbon material, and only the aromatic solvent is recovered from the solid component. Charcoal may be discarded.
Moreover, although solid-liquid separation in acquisition of the above-mentioned 1st ashless coal, 2nd ashless coal, and byproduct coal can be performed sequentially using the same apparatus, even if it performs using each another apparatus, Good. Furthermore, in acquisition of 1st ashless coal, 2nd ashless coal, and byproduct coal, you may make it acquire these simultaneously at the same timing, and acquires any one or two first. You may do it.

  Although the present invention is as described above, in carrying out the present invention, within the range that does not adversely affect the respective steps, for example, a coal pulverization step of pulverizing raw coal between or before and after the respective steps, Other steps such as a removal step of removing unnecessary substances such as garbage and a drying step of drying the obtained ashless coal may be included.

Next, an example is given and the manufacturing method of ashless coal concerning the present invention is explained concretely.
[First embodiment]
In the first example, the relationship between the heating temperature in the first slurry heating step and the properties of the obtained first ashless coal was examined (first experimental example).

  4 kg (20 kg) of aromatic solvent (1-methylnaphthalene (manufactured by Nippon Steel Chemical Co., Ltd.)) is mixed with 5 kg of bituminous coal (carbon content 84.5% by mass (daf basis)) as a raw material slurry. Was prepared. This slurry was pressurized with 1.2 MPa of nitrogen and heat-treated (heat extraction) for 30 minutes at a temperature shown in Table 1 in an autoclave with an internal volume of 30 liters. The slurry is separated into a supernatant (first supernatant) and a solid concentrate (first solid concentrate) in a gravity sedimentation tank maintained at the same temperature and pressure, and the fragrance is distilled from the first supernatant by distillation. The ashless coal (first ashless coal) was produced by separating and recovering the group solvent.

About the obtained 1st ashless coal, the ashless coal yield (extraction rate) was calculated | required.
Specifically, it was determined by the formula: (mass of first ashless coal / mass of raw coal) × 100.
The raw coal is based on anhydrous ashless coal.
In addition, the obtained first ashless coal was subjected to the Gieseler softening flow test specified in JIS M8801, and the softening temperature was obtained.

Next, a carbide was produced from the first ashless coal.
100 g of first ashless charcoal was placed in an autoclave having an internal volume of 0.5 liter, and heat treatment was performed under a treatment condition of 400 ° C. × 40 minutes under a nitrogen flow of 1 liter / min. The heat-treated ashless coal was used as a carbon raw material.

Next, the carbon raw material is pulverized to 0.149 mm or less (passing through a sieve having an opening of 0.149 mm), and the pulverized carbon raw material is filled with 5 g in a mold having a cylindrical cavity with a diameter of 30 mm. And press molding at a pressure of 0.5 ton / cm ² to produce a molded body having a thickness of 7.1 mm. The molded body was heated at a rate of 1 ° C./min in a nitrogen atmosphere and carbonized at 1200 ° C. to produce a carbide.
About the obtained carbide | carbonized_material, the carbon yield was calculated | required.
Specifically, it was determined by the formula of (mass of carbide / mass of carbon raw material) × 100. The mass of the carbide is the mass of the generated carbon, and the mass of the carbon raw material is the mass of the heat-treated ashless coal.
The results are shown in Table 1.

  As shown in Table 1, it can be seen that up to 390 ° C., the higher the heating temperature, the better the ashless coal yield, the softening temperature, and the carbon yield. Moreover, when heating temperature is 200 degreeC, it turns out that an ashless coal yield is low compared with another thing. Furthermore, when heating temperature is 390 degreeC, softening temperature is 265 degreeC, and it turns out that it does not become low compared with the softening temperature (200-300 degreeC) of general ashless coal.

[Second Embodiment]
In the second example, in the first example, the heat treatment temperature in the first slurry heating step is 300 ° C., 350 ° C., 200 ° C., and the heating temperature in the second slurry heating step is obtained. The relationship between the properties of ashless coal was examined (second experimental example).

The 2nd ashless coal was manufactured using the 1st solid content concentrate obtained in the said 1st Example.
A slurry was prepared by mixing 3 kg (15 kg) of an aromatic solvent (1-methylnaphthalene (manufactured by Nippon Steel Chemical Co., Ltd.)) with respect to 5 kg of the first solid content concentrate. This slurry was pressurized with 1.2 MPa of nitrogen and subjected to heat treatment (heat extraction) at a temperature shown in Table 2 for 30 minutes in an autoclave having an internal volume of 30 liters. This slurry is separated into a supernatant (second supernatant) and a solid concentrate (second solid concentrate) in a gravity sedimentation tank maintained at the same temperature and pressure, and the second supernatant is aromatized by distillation. The ash-free coal (second ash-free coal) was produced by separating and recovering the group solvent.

About the obtained 2nd ashless coal, the ashless coal yield (extraction rate) was calculated | required.
Specifically, it was determined by the formula (mass of second ashless coal / mass of raw coal) × 100.
The raw coal is based on anhydrous ashless coal.
In addition, the obtained second ashless coal was subjected to the Gieseler softening flow test specified in JIS M8801, and the softening temperature was obtained.

Next, a carbide was produced from the second ashless coal by the same method as in the first example, and the carbon yield of the obtained carbide was determined by the same method as in the first example.
The results are shown in Table 2.

  As shown in Table 2, when the heating temperature in the first slurry heating step is 300 ° C., the heating temperature in the second slurry heating step is not higher than the heating temperature in the first slurry heating step (No. 6: 300 ° C.), the yield of ashless coal is low compared to the others, and the softening temperature is 110 ° C., which is higher than the softening temperature of general ashless coal (200 to 300 ° C.). I understand that it doesn't become. When the heating temperature in the second slurry heating step is too high (No. 9: 450 ° C.), the ashless coal yield is No. 9. It is low compared with 8, softening temperature is 295 degreeC, and it turns out that it does not become high compared with the softening temperature (200-300 degreeC) of general ashless coal.

  Moreover, when the heating temperature in the first slurry heating step is 350 ° C., the heating temperature in the second slurry heating step is not higher than the heating temperature in the first slurry heating step (No. 10: 350 ° C.). It can be seen that the ashless charcoal yield is lower than the others, and the softening temperature is 235 ° C., which is not higher than the softening temperature of general ashless coal (200 to 300 ° C.). When the heating temperature in the second slurry heating step is too high (No. 13: 450 ° C.), the ashless coal yield is No. It is low compared to 11 and 12, and the softening temperature is 280 ° C., which is not higher than the softening temperature of general ashless coal (200 to 300 ° C.).

Furthermore, when the heating temperature in the first slurry heating step is 200 ° C., the softening temperature is 240 ° C. or 275 ° C., which is higher than the softening temperature of general ashless coal (200 to 300 ° C.). I understand that it doesn't become.
Note that when the heating temperature in the first slurry heating step is 390 ° C., it is clear that almost no solvent extraction occurs in the second slurry heating step, and thus the experiment is omitted here.

As described above, from the results of the first example and the second example, the heating temperature in the second slurry heating step needs to be higher than the first slurry heating temperature. Preferably, the first slurry heating temperature is 250-350 degreeC and the heating temperature in a 2nd slurry heating process are understood that it is 350-420 degreeC.
Further, according to the method for producing ashless coal according to the present invention, the softening temperature is high and the ashless coal (second ashless coal) capable of improving the carbon yield, the softening temperature is low, and the thermal fluidity is achieved. It can be seen that ashless coal (first ashless coal) that is superior to the above can be produced simultaneously with high efficiency and in a simple manner.

  As mentioned above, although the best embodiment and the example were shown and explained in detail about the manufacturing method of ashless coal concerning the present invention, the meaning of the present invention is not limited to the above-mentioned contents, and the scope of right is patent. It should be interpreted broadly based on the claims. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

It is a flowchart explaining the process of the manufacturing method of ashless coal. It is a schematic diagram which shows the outline of the manufacturing method of ashless coal. It is a schematic diagram which shows the solid-liquid separator for performing a gravity sedimentation method.

Explanation of symbols

S1 1st slurry heating process S2 1st separation process S3 2nd slurry heating process S4 2nd separation process S5 modified coal acquisition process 1 coal slurry preparation tank 2 pump 3 preheater 4 extraction tank 5 gravity sedimentation tank 6 solid content concentrate Receiver 7 Cooler 8 Filter unit 9 Supernatant receiver 10 Stirrer 100 Solid-liquid separator

Claims (2)

A first slurry heating step of heating a slurry in which coal and an aromatic solvent are mixed;
A first separation step of separating the slurry heat-treated in the first slurry heating step into a liquid component in which coal is dissolved and a solid component containing ash and insoluble coal;
A second slurry heating step of adding and mixing an aromatic solvent to the solid component separated in the first separation step, and heat-treating the mixed slurry at a temperature higher than the heat treatment in the first slurry heating step; ,
A second separation step of separating the slurry heat-treated in the second slurry heating step into a liquid component in which coal is dissolved and a solid component containing ash and insoluble coal;
A modified coal acquisition step of acquiring ashless coal, which is a modified coal,
The upgraded coal acquisition step, before SL to remove the aromatic solvent from the separated liquid components in the first separation step, the first ash-free coal obtaining step of obtaining the ashless coal which is modified coal, the A second ashless coal acquisition step of removing an aromatic solvent from the liquid component separated in the second separation step and acquiring ashless coal as reformed coal, Production method. The upgraded coal acquisition step, in addition to obtaining the ashless coal from a liquid component separated in the first liquid component separated in the separation step and the second separation step, is La, the second 2. The ashless coal according to claim 1, further comprising a by -product coal acquisition step of removing the aromatic solvent from the solid component separated in the separation step to obtain a by-product coal that is a modified coal. Manufacturing method.

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