JP6017337B2 - Production method of ashless coal - Google Patents

Description

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

  Patent Document 1 discloses a method for producing ashless coal. In this manufacturing method, a coal raw material in which caking coal is mixed with general coal and a solvent are mixed to prepare a slurry, the obtained slurry is heated to extract a coal component soluble in the solvent, and the coal component is extracted. From the extracted slurry, a solution containing coal components soluble in the solvent and a solid concentrate containing coal components insoluble in the solvent are separated from each other by gravity precipitation, and the solvent is separated from the separated solution. I have ash charcoal.

JP 2009-227718 A

  By the way, coke which is a fuel for a steelmaking blast furnace is produced by dry distillation of coal. When the temperature of the coal exceeds 300 ° C., the coal is pyrolyzed to generate a gas or a liquid substance, and is softened and melted and expanded. At the same time as the expansion, the particles adhere to each other, and further degass and contract to become coke.

  Here, the coal used as a raw material for coke needs to have a certain degree of fluidity (softening and melting property) and expansibility. Specifically, coke coking coal preferably has a maximum fluidity (log MF) of about 2 to 3 (logddpm) as measured by the Giesler plastometer method and a total expansion rate of 75% or less as measured by the dilatometer method. However, ashless coal is a caking additive (coal extraction component) with very excellent fluidity, and its fluidity and expansibility are too large. Specifically, the ashless coal has a maximum fluidity (log MF) of 4.5 (logddpm) or more according to the Gieseller Plastometer method and a total expansion rate of 200% or more by the dilatometer method. Therefore, it is difficult to produce coke by dry distillation of only ashless coal. In order to produce coke only from ashless coal, it is necessary to reduce the fluidity and expansibility of ashless coal to values suitable for coke production.

  The objective of this invention is providing the manufacturing method of ashless coal which can reduce the fluidity | liquidity and expansibility of ashless coal.

The method for producing ashless coal in the present invention is 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 slurry obtained in the extraction step, A separation step of separating the solution in which the coal component soluble in the solvent is dissolved, and a solid content concentrate in which the coal component insoluble in the solvent is concentrated, and evaporating and separating the solvent from the solution separated in the separation step. An ashless coal obtaining step for obtaining ash charcoal, and a byproduct coal obtaining step for obtaining a byproduct charcoal by evaporating and separating the solvent from the solid concentrate separated in the separation step. And oxidizing the surface of the ashless coal and oxidizing the surface of the byproduct coal in the byproduct coal acquisition step .

  According to the method for producing ashless coal of the present invention, the fluidity and expansibility of ashless coal can be reduced.

It is a schematic diagram of a manufacturing apparatus. It is a graph which shows the measurement result of fluidity | liquidity. It is a schematic diagram of a steam tube dryer.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Configuration of ashless coal production facility)
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, solvent separators 9 and 10, and dryers 11 and 12 are provided.

  Here, the manufacturing method of the ashless coal of this embodiment has a slurry preparation process, an extraction process, a separation process, an ashless coal acquisition process, and a byproduct coal acquisition process. Hereinafter, each step will be described. In addition, there is no restriction | limiting in particular in the coal used as a raw material in this manufacturing method, A bituminous coal with a high extraction rate may be used, and cheaper inferior quality coal (subbituminous coal, lignite) may be used. The ashless coal means ash content of 5% by weight or less, preferably 3% by weight or less.

(Slurry preparation process)
The slurry preparation step is a step of preparing a slurry by mixing coal and a solvent. This slurry preparation process is implemented in the slurry preparation tank 3 in FIG. Coal as a raw material is charged into the slurry preparation tank 3 from the coal hopper 1, and a solvent is charged into the slurry preparation tank 3 from the solvent tank 2. The coal and solvent charged into the slurry preparation tank 3 are mixed by the stirrer 3a to become a slurry composed of coal and solvent.

  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.

(Extraction process)
The extraction step is a step of heating the slurry obtained in the slurry preparation step to extract a coal component soluble in the solvent (dissolve in the solvent). This 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 supplied to the preheater 5 by the transfer pump 4 and heated to a predetermined temperature, then supplied to the extraction tank 6, and held at the predetermined temperature while being stirred by the stirrer 6a. Extraction is performed.

  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 viewpoints 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.

  The heating temperature of the slurry in the extraction step is not particularly limited as long as the solvent-soluble component can be dissolved, and is, for example, 300 to 420 ° C. from the viewpoint of sufficient dissolution of the solvent-soluble component and improvement of the extraction rate. 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 extraction process 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.

(Separation process)
In the separation step, the slurry obtained in the extraction step is subjected to a gravity sedimentation method, a solution in which a coal component soluble in a solvent is dissolved, and a solid content in which a coal component insoluble in a solvent (a solvent insoluble component such as ash) is concentrated. This is a step of separating into a concentrated liquid (solvent insoluble component concentrated liquid). This separation step is performed in the gravity settling tank 7 in FIG. The slurry obtained in the extraction step is separated into a supernatant liquid as a solution and a solid content concentrated liquid by gravity in the gravity settling tank 7. 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 solvent-insoluble component (for example, ash) having a specific gravity greater than that of a solution in which a coal component soluble in a solvent is dissolved is settled by gravity in the lower portion of the gravity settling tank 7. 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 sedimentation tank 7 is preferably kept warm (or heated) or pressurized in order to prevent reprecipitation of solvent-soluble components eluted from coal. The heat retention (heating) temperature is, for example, 300 to 380 ° C., and the tank internal pressure is, for example, 1.0 to 3.0 MPa.

  As a method for separating the solution containing the coal component dissolved in the solvent from the slurry obtained 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 (HPC) by evaporating and separating the solvent from the solution (supernatant liquid) separated in the separation step. This ashless coal acquisition step includes an ashless coal mixture acquisition step and an ashless coal drying step.

<Ashless coal mixture acquisition process>
The ashless coal mixture acquisition step is a step of obtaining an ashless coal mixture in which the solvent remains in the ashless coal by evaporating and separating the solvent from the solution separated in the separation step. This ashless coal mixture acquisition step is performed by the solvent separator 9 in FIG. The solution separated in the gravity settling tank 7 is filtered by the filter unit 8 and then supplied to the solvent separator 9, and the solvent is evaporated and separated from the supernatant in the solvent separator 9. Here, it is preferable that the solvent is separated from the solution in the presence of an inert gas such as nitrogen. In this embodiment, the solvent separator 9 is a flash distillation tank used for flash distillation. In the flash distillation method, the solvent is evaporated and separated by spraying the solution in a tank in a nitrogen gas atmosphere.

  The method for separating the solvent from the solution (supernatant) is not limited to the flash distillation method, and a general distillation method, evaporation method, or the like can be used. The solvent separated by the solvent separator 9 is returned to the solvent tank 2 and circulated and used repeatedly. In addition, although it is preferable to circulate and use a solvent, it is not indispensable (the same is true in the by-product charcoal acquisition step described later). By separating the solvent from the supernatant, it is possible to obtain an ashless coal mixture in which the solvent remains in the ashless coal at a ratio of approximately 20% by weight to 30% by weight.

<Ashless coal drying process>
The ashless coal drying step is a step of obtaining ashless coal by evaporating and separating the remaining solvent from the ashless coal mixture, which is a mixture of ashless coal and a solvent. This ashless coal drying step is performed by a dryer 11 in FIG. The ashless coal mixture obtained by the solvent separator 9 is supplied to the dryer 11, and the solvent remaining from the ashless coal mixture is evaporated and separated in the dryer 11. The solvent is preferably separated from the ashless coal mixture in the presence of an inert gas such as nitrogen. In the present embodiment, the dryer 11 is a steam tube dryer in which nitrogen gas as a carrier gas flows. By separating the remaining solvent from the ashless coal mixture, ashless coal (HPC) substantially free of ash can be obtained.

  Ashless coal contains almost no ash, has no moisture, and exhibits a higher calorific value than raw coal. Furthermore, softening meltability (fluidity), 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) is good even if the raw coal does not have softening meltability Soft meltability. Therefore, ashless coal can be used, for example, as a blended coal for coke raw materials. In addition, ashless coal containing almost no ash content has high combustion efficiency and can reduce the generation of coal ash. Therefore, the use of ashless coal as a gas turbine direct injection fuel in a high-efficiency combined power generation system based on gas turbine combustion has attracted attention.

  Here, in this embodiment, a part of the surface of the ashless coal is oxidized with oxygen mixed in the nitrogen gas by supplying oxygen into the dryer 11 in which the inside is a nitrogen gas atmosphere. . Note that the entire surface of the ashless coal may be oxidized. The mixing ratio of oxygen into the nitrogen gas depends on conditions such as the amount and temperature of the ashless coal to be oxidized and the circulation amount of the nitrogen gas, but can be, for example, about 21% by volume or less.

  Conventionally, it is known that when coal is oxidized at a low temperature (room temperature to around 380 ° C.), fluidity (softening and melting property) and expansibility are lowered. Therefore, by oxidizing at least a part of the surface of the ashless coal, the fluidity and expansibility of the ashless coal are reduced to values suitable for coke production. In this way, coke can be produced only from ashless coal.

  In addition, as a method of oxidizing the surface of ashless coal, oxygen is mixed in the solvent separator 9 to oxidize the surface of ashless coal contained in the ashless coal mixture, and oxygen is contained in the dryer 11. There are a method of oxidizing the surface of ashless coal by mixing ash and a method of oxidizing the surface of ashless coal discharged from the dryer 11. Here, the amount of the solvent contained in the ashless coal obtained by the dryer 11 is smaller than that of the ashless coal mixture obtained in the solvent separator 9. Therefore, ashless coal is easier to touch the surface and oxidize than ashless coal mixture. Moreover, since the ashless coal in the dryer 11 is higher in temperature than the ashless coal discharged from the dryer 11, it is more easily oxidized. For the above reasons, the method of mixing oxygen into the dryer 11 is the most suitable method for oxidizing the surface of ashless coal. Further, if the dryer 11 is a steam tube dryer, oxygen is more easily touched by the surface of the ashless coal by diffusing oxygen on the flowing nitrogen gas flow.

(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 solid concentrate separated in the separation step. This byproduct charcoal acquisition process has a byproduct charcoal mixture acquisition process and a byproduct charcoal drying process.

<By-product coal mixture acquisition process>
The byproduct charcoal mixture acquisition step is a step of obtaining a byproduct charcoal mixture in which the solvent remains in the byproduct charcoal by evaporating and separating the solvent from the solid content concentrate separated in the separation step. This byproduct charcoal mixture acquisition step is performed by the solvent separator 10 in FIG. The solid content concentrate separated in the gravity sedimentation tank 7 is supplied to the solvent separator 10, and the solvent is evaporated and separated from the solid content concentrate in the solvent separator 10. Here, it is preferable to carry out the evaporation and separation of the solvent from the solid concentrate in the presence of an inert gas such as nitrogen. In this embodiment, the solvent separator 10 is a flash distillation tank used for flash distillation.

  The method for separating the solvent from the solid concentrate is not limited to the flash distillation method, and a general distillation method and evaporation method can be used in the same manner as the above-described ashless coal acquisition step. The solvent separated by the solvent separator 10 is returned to the solvent tank 2 and circulated and used repeatedly. By separating the solvent from the solid concentrate, it is possible to obtain a by-product charcoal mixture in which the solvent remains in the by-product charcoal at a ratio of approximately 5 wt% to 10 wt%.

<By-product charcoal drying process>
The byproduct coal drying step is a step of obtaining byproduct coal by evaporating and separating the remaining solvent from the byproduct coal mixture. This by-product charcoal drying step is performed by a dryer 12 in FIG. The by-product coal mixture obtained in the solvent separator 10 is supplied to the dryer 12, and the remaining solvent from the by-product coal mixture is evaporated and separated in the dryer 12. The solvent is preferably separated from the by-product coal mixture in the presence of an inert gas such as nitrogen. In the present embodiment, the dryer 12 is a steam tube dryer in which nitrogen gas as a carrier gas flows. By separating the remaining solvent from the by-product coal mixture, it is possible to obtain by-product coal (RC, also referred to as residual coal) in which solvent-insoluble components including ash and the like are concentrated.

  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.

  Here, in this embodiment, by supplying oxygen into the dryer 12 whose inside is in a nitrogen gas atmosphere, a part of the surface of the by-product coal is oxidized with oxygen mixed in the nitrogen gas. . In addition, you may oxidize the whole surface of byproduct charcoal. The mixing ratio of oxygen into the nitrogen gas depends on conditions such as the amount and temperature of by-product coal to be oxidized and the circulation amount of the nitrogen gas, but can be about 21% by volume or less, for example.

  Generally, coal generates heat when it is oxidized, and spontaneously ignites when heat is intense. By-product charcoal is an insoluble component that is insoluble in a solvent and has a structure in which pores are developed. Therefore, by oxidizing the surface of the by-product coal to some extent when obtaining the by-product coal, the absolute amount that the by-product coal is subsequently oxidized is reduced. Thereby, byproduct charcoal can be made hard to ignite spontaneously.

  As a method of oxidizing the surface of the byproduct coal, a method of oxidizing the surface of the byproduct coal contained in the byproduct coal mixture by mixing oxygen in the solvent separator 10 and an oxygen in the dryer 12 are used. There are a method of oxidizing the surface of by-product coal by mixing and a method of oxidizing the surface of by-product coal discharged from the dryer 12. Here, the amount of the solvent contained in the by-product coal obtained by the dryer 12 is smaller than that of the by-product coal mixture obtained by the solvent separator 10. Therefore, by-product coal is easier to touch the surface and oxidize than by-product coal mixture. Further, the by-product coal in the dryer 12 is easier to oxidize than the by-product coal discharged from the dryer 12 because the temperature is higher. For the above reasons, the method of mixing oxygen into the dryer 12 is the most suitable method for oxidizing the surface of the by-product coal. Further, when the dryer 12 is a steam tube dryer, oxygen is more easily brought into contact with the surface of the byproduct charcoal because oxygen is diffused by the flowing nitrogen gas flow.

(Fluidity measurement)
Next, fluidity was measured using ashless coal containing 5% by weight of a solvent as raw material and ashless charcoal obtained by oxidizing a part of the surface of the raw material and the raw material. Specifically, in the ashless coal acquisition process, the solvent remaining from the ashless coal mixture is evaporated and separated by a steam tube dryer to obtain ashless coal as a raw material, and in the nitrogen gas circulating in the steam tube dryer The mixture was mixed with oxygen at a predetermined concentration to obtain ashless coal in which a part of the surface of the raw material was oxidized. The Gieseller fluidity was measured for both. The result is shown in FIG.

  Here, the steam tube dryer will be described. As shown in FIG. 3, the steam tube dryer 11 has a long cylindrical main body 12, driving means 13 such as a motor, and a number of steam tubes 14. The main body 12 is arranged in the lateral direction so as to be slightly downward along the center line O from one end (left end in the figure) to the other end (right end in the figure). The driving means 13 supports the main body 12 so as to be rotatable around its center line O. A plurality of steam tubes 14 are attached to the inner wall side of the main body 12 so as to extend in parallel with the center line O and to be arranged in a plurality of circumferential directions and radial directions so as to form concentric circles around the center line O. And steam as a heating medium is circulated inside.

  A screw feeder 18 driven by a driving means 17 such as a motor is provided on one end side of the main body 12. The screw feeder 18 is provided with a supply port 15 through which a processed product (ashless coal mixture) W to be dried is supplied and a suction port 16 through which a nitrogen gas G as a carrier gas is sucked. The screw feeder 18 is airtightly arranged with respect to the main body 12 so as to be inserted into the inner peripheral side of the steam tube 14 while allowing the main body 12 to rotate.

  On the other hand, a box 21 is provided on the other end side of the main body 12. The box 21 includes a discharge port 19 for a processed product (ashless coal) W dried by the steam tube dryer 11 at a lower portion and an exhaust port 20 for a nitrogen gas G at an upper portion. The box 21 is disposed so that the inside of the main body 12 can be kept airtight while allowing the main body 12 to rotate. The other end of the main body 12 is provided with steam supply pipes 22 and drain pipes 23 for a number of steam tubes 14.

  In such a steam tube dryer 11, the processed product (ashless coal mixture) W supplied from the supply port 15 of the screw feeder 18 is passed through the inner periphery of many steam tubes 14 from one end of the main body 12 by the screw feeder 18. , While being in contact with a number of steam tubes 14 by the rotation of the main body 12, it is sent to the other end side while being rolled, while being indirectly heated by steam through the steam tube 14 and dried. It is discharged as a processed product (ashless coal) W from a discharge port 19 on the other end side of the main body 12. In addition, the solvent evaporated from the treated product (ashless coal mixture) W by this drying, together with the nitrogen gas G sucked from the suction port 16 of the screw feeder 18 on one end side of the main body 12, also on the other end side of the main body 12. It is discharged from the exhaust port 20 and collected.

In the present embodiment, the flow rate of the nitrogen gas G is 1.0 Nm ³ / h, the residence time of the treated product (ashless coal mixture) W in the main body 12 is 90 minutes, and the steam pressure is 2.55 MPa (225 ° C.). As a result, the remaining solvent was evaporated and separated from the ashless coal mixture. And one side of the main body 12 was opened to the atmosphere so that a small amount of oxygen was present.

  As shown in FIG. 2, the raw material reached the measurement limit value in the range from about 320 ° C. to about 430 ° C. On the other hand, the ashless coal whose surface was partially oxidized showed fluidity about half that of the raw material at around 320 ° C. Moreover, the ashless coal in which a part of the surface was oxidized reached the measurement limit value in the range from about 380 ° C. to about 410 ° C., and showed lower fluidity than the measurement limit value in the temperature range higher than 410 ° C. . This shows that the fluidity of ashless coal falls by oxidizing the surface of ashless coal.

(effect)
As described above, according to the method for producing ashless coal according to the present embodiment, the surface of the ashless coal is oxidized when the solvent is evaporated from the solution to obtain ashless coal. Here, it is known that when coal is oxidized at a low temperature (room temperature to around 380 ° C.), fluidity (softening and melting property) and expansibility are lowered. Therefore, by oxidizing the surface of ashless coal, the fluidity and expansibility of ashless coal are reduced to values suitable for coke production. In this way, coke can be produced only from ashless coal. Thus, the fluidity and expansibility of ashless coal can be reduced by oxidizing the surface of ashless coal.

  Further, the surface of ashless coal is oxidized with oxygen mixed in an inert gas. If it is in an inert gas, the surface of ashless coal easily reacts with oxygen, so that the surface of ashless coal can be suitably oxidized.

  Moreover, the amount of the solvent contained in the ashless coal obtained in the ashless coal drying step is smaller than that in the ashless coal mixture obtained in the ashless coal mixture acquisition step. Therefore, ashless coal is easier to touch the surface than ashless coal mixture. Then, the surface of ashless coal can be oxidized suitably by oxidizing the surface of ashless coal in an ashless coal drying process.

  Further, when the by-product coal is obtained by evaporating and separating the solvent from the solid content concentrate, the surface of the by-product coal is oxidized. Generally, coal generates heat when it is oxidized, and spontaneously ignites when heat is intense. By-product charcoal is an insoluble component that is insoluble in a solvent and has a structure in which pores are developed. Therefore, by oxidizing the surface of the by-product coal to some extent when obtaining the by-product coal, the absolute amount that the by-product coal is subsequently oxidized is reduced. Thereby, byproduct charcoal can be made hard to ignite spontaneously.

  Further, the surface of the by-product coal is oxidized with oxygen mixed in the inert gas. If in the inert gas, the surface of the by-product coal easily reacts with oxygen, so that the surface of the by-product coal can be suitably oxidized.

  Moreover, the amount of the solvent contained in the by-product coal obtained in the by-product coal drying step is smaller than that of the by-product coal mixture obtained in the by-product coal mixture acquisition step. Therefore, by-product coal is easier to touch the surface than by-product coal mixture. Therefore, the surface of the by-product coal can be suitably oxidized by oxidizing the surface of the by-product coal in the by-product coal drying step.

(Modification of this embodiment)
The embodiment of the present invention has been described above, but only specific examples are illustrated, and the present invention is not particularly limited, and the specific configuration and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to what was done.

DESCRIPTION OF SYMBOLS 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 11,12 Dryer 100 Ashless coal production equipment

Claims (5)

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 slurry obtained in the extraction step into a solution in which a coal component soluble in a solvent is dissolved and a solid content concentrate in which a coal component insoluble in a solvent is concentrated;
Ashless coal acquisition step of obtaining ashless coal by evaporating and separating the solvent from the solution separated in the separation step;
A byproduct charcoal obtaining step of obtaining a byproduct charcoal by evaporating and separating the solvent from the solid concentrate separated in the separation step;
With
In the ashless coal acquisition step, the surface of the ashless coal is oxidized ,
In the by-product charcoal acquisition step, the surface of the by-product coal is oxidized .   The method for producing ashless coal according to claim 1, wherein in the ashless coal acquisition step, the surface of the ashless coal is oxidized with oxygen mixed in an inert gas. The ashless coal acquisition step includes:
An ashless coal mixture obtaining step for obtaining an ashless coal mixture in which the solvent remains in the ashless coal by evaporating and separating the solvent from the solution separated in the separation step;
Ashless coal drying step for obtaining ashless coal by evaporating and separating the remaining solvent from the ashless coal mixture,
Have
The method for producing ashless coal according to claim 1 or 2, wherein a surface of the ashless coal is oxidized in the ashless coal drying step. 2. The method for producing ashless coal according to claim 1 , wherein, in the byproduct coal acquisition step, the surface of the byproduct coal is oxidized with oxygen mixed in an inert gas. The byproduct charcoal acquisition step includes
By-product coal mixture obtaining step of obtaining a by-product coal mixture in which the solvent remains in the by-product coal by evaporating and separating the solvent from the solid content concentrate separated in the separation step;
A by-product coal drying step of obtaining a by-product coal by evaporating and separating the solvent remaining from the by-product coal mixture;
Have
The sub in living coal drying process, the manufacturing method of the ashless coal according to claim 1 or 4, wherein the oxidizing the surface of the residue coal.

Images