WO2018216373A1

WO2018216373A1 - Method for producing ashless coal and device for producing ashless coal

Info

Publication number: WO2018216373A1
Application number: PCT/JP2018/014885
Authority: WO
Inventors: 康爾堺; 憲幸奥山; 吉田　拓也; 繁木下
Original assignee: 株式会社神戸製鋼所
Priority date: 2017-05-24
Filing date: 2018-04-09
Publication date: 2018-11-29
Also published as: JP2018197306A; CN110651027A; JP6827884B2; KR20200004872A; KR102291836B1; CN110651027B

Abstract

The method for producing ashless coal according to an embodiment of the present invention includes: a step of heating a mixture of coal, a radical stabilizer, and a solvent; a step of eluting components soluble in the solvent from the coal in the slurry obtained in the heating step; a step of separating the slurry after elution in the eluting step into a liquid containing the solvent soluble components and solvent insoluble components; and a step of evaporating the solvent from the liquid separated in the separating step. The device for producing ashless coal according to an embodiment of the present invention includes: a heating unit that heats a mixture of coal, a radical stabilizer, and a solvent; an eluting unit that elutes components soluble in the solvent from the coal in the slurry obtained by the heating unit; a solid-liquid separating unit that separates the slurry after elution by the eluting unit into a liquid containing the solvent soluble components and solvent insoluble components; and an evaporating separating unit that evaporates the solvent from the liquid separated by the solid-liquid separating unit.

Description

Ashless coal manufacturing method and ashless coal manufacturing apparatus

The present invention relates to a method for producing ashless coal and an apparatus for producing ashless coal.

Coal is widely used as a raw material for thermal power generation and boiler fuel or chemicals. As one of the environmental measures, the development of technology that efficiently removes ash in coal is strongly desired. For example, in a high-efficiency combined power generation system using gas turbine combustion, attempts have been made to use ash-free charcoal (HPC) from which ash has been removed as a fuel to replace liquid fuel such as LNG. Attempts have also been made to use ashless coal as coking coal for ironmaking coke such as blast furnace coke.

As a method for producing ashless coal, a method of separating a solution containing a coal component soluble in a solvent (hereinafter also referred to as a solvent-soluble component) from a slurry using a gravity sedimentation method has been proposed (for example, JP, A 2005-120185). This method includes a slurry preparation step in which coal and a solvent are mixed to prepare a slurry, and an extraction step in which the slurry obtained in the slurry preparation step is heated to extract a solvent-soluble component. This method further includes a separation step of separating the solution in which the solvent-soluble component is dissolved from the slurry from which the solvent-soluble component has been extracted in the extraction step, and separating the solvent from the solution separated in the separation step to obtain ashless coal. An ashless coal acquisition step.

In addition, a method for producing ashless coal that can shorten the extraction time of the solvent-soluble component from the conventional method for producing ashless coal has been proposed (see JP-A-2016-56282). In this method for producing ashless coal, the time for extracting solvent-soluble components is shortened by rapidly heating the slurry in which the solvent and coal are mixed.

In any of these conventional methods for producing ashless coal, ashless coal is obtained by separating the solvent from a solution containing a coal component that is soluble in the solvent. Therefore, the yield of ashless coal depends on the proportion of coal components soluble in the solvent, that is, the extraction rate. For this reason, in order to raise the manufacture efficiency of ashless coal, the further improvement of this extraction rate is desired.

Japanese Patent Laid-Open No. 2005-120185 JP 2016-56282 A

The present invention has been made based on the above circumstances, and an object thereof is to provide a method for producing ashless coal and an apparatus for producing ashless coal with an increased extraction rate.

The inventors of the present invention have found that the extraction rate of ashless coal can be increased by adding a radical stabilizer to the slurry before heating to extract the solvent-soluble component, and completed the present invention. This is presumably because the radical stabilizer can suppress polymerization due to polycondensation of coal radicals caused by heating the slurry.

That is, the invention made in order to solve the above problems includes a step of heating a mixture of coal, a radical stabilizer and a solvent, and a component soluble in the solvent from the coal in the slurry obtained in the heating step. An elution step, a step of separating the slurry eluted in the elution step into a liquid component containing a solvent-soluble component and a solvent insoluble component, and a step of evaporating the solvent from the liquid component separated in the separation step. A method for producing ashless coal.

In the method for producing ashless coal, a radical stabilizer is added to the slurry before heating to extract solvent-soluble components. Since this radical stabilizer can suppress polymerization due to polycondensation of coal radicals caused by heating of the slurry, it is possible to increase the soluble components of coal eluted in the elution step. Therefore, the extraction rate of ashless coal can be increased by using the method for producing ashless coal.

The heating step may include a step of mixing coal, a radical stabilizer and a solvent, and a step of raising the temperature of the slurry obtained in the mixing step. In this way, in the heating step, by heating the slurry after mixing the radical stabilizer, the polymerization of coal radicals can be effectively suppressed, so that the extraction rate of ashless coal can be further increased.

The heating step includes a step of heating a solvent, a step of transporting the solvent heated in the solvent heating step to the elution step, and a step of supplying coal and a radical stabilizer to the solvent in the solvent transport step. It is good to have. Thus, by supplying coal to the heated solvent in conveyance, coal can be heated up rapidly and coal and a solvent can be stirred with the flow of a solvent. Thereby, coal can be melt | dissolved in a solvent in a short time. Further, by supplying a radical stabilizer together with coal, it is possible to effectively inhibit the polymerization of coal radicals, thereby further increasing the extraction rate of ashless coal.

It is good to adjust the heating temperature of the solvent in the solvent heating step so that the heating rate of coal in the supplying step is 600 ° C./min or more. In this way, by setting the coal heating rate in the supply step to be equal to or higher than the lower limit, it is possible to more effectively suppress the polymerization of coal radicals, thereby further increasing the extraction rate of ashless coal.

The amount of the radical stabilizer added to coal on an anhydrous coal basis is preferably 0.045 mmol / g or more and 0.4 mmol / g or less. By making the addition amount of the radical stabilizer within the above range, it is possible to effectively increase the extraction rate of ashless coal while suppressing an increase in production cost due to the addition of the radical stabilizer.

The radical stabilizer is preferably an amine or an ammonium salt. Thus, the extraction rate of ashless charcoal can further be raised by using the radical stabilizer as an amine or an ammonium salt.

The amine is preferably a monoamine, diamine or triamine. Thus, by making the said amine into monoamine, diamine or triamine, it is possible to effectively increase the extraction rate of ashless coal while suppressing an increase in production cost due to the addition of the radical stabilizer.

Another invention made to solve the above-mentioned problems is a heating part for heating a mixture of coal, a radical stabilizer and a solvent, and a component soluble in the solvent from the coal in the slurry obtained in the heating part. An elution part for elution, a solid-liquid separation part for separating the slurry after elution in the elution part into a liquid component containing a solvent-soluble component and a solvent-insoluble component, and the liquid component separated in the solid-liquid separation unit An ashless coal manufacturing apparatus including an evaporation separation unit that evaporates a solvent.

The said ashless coal manufacturing apparatus extracts the solvent-soluble component by heating the slurry to which the radical stabilizer is added in the heating section. Since this radical stabilizer can suppress polymerization due to the polycondensation of coal radicals caused by heating the slurry, it is possible to increase the soluble components of coal eluted in the elution part. Therefore, the extraction rate of ashless coal can be increased by using the ashless coal manufacturing apparatus.

Here, ashless coal (Hypercoal, HPC) is a type of modified coal obtained by reforming coal, and a modified coal that removes ash and insoluble components from coal as much as possible using a solvent. It is. However, the ashless coal may contain ash as long as the fluidity and expansibility of the ashless coal are not significantly impaired. In general, coal contains ash content of 7% by mass or more and 20% by mass or less, but ashless coal may contain ash content of about 2% by mass, and in some cases about 5% by mass. “Ash” means a value measured in accordance with JIS-M8812: 2004.

As described above, the extraction rate of ashless coal can be increased by using the method and apparatus for producing ashless coal of the present invention.

It is the schematic which shows the manufacturing apparatus of the ashless coal of 1st embodiment of this invention. It is the schematic which shows the heating part different from the heating part of the manufacturing apparatus of ashless coal of FIG. It is a graph which shows the relationship between the addition amount of the monoamine in an Example, and an extraction rate increase rate. It is a graph which shows the relationship between the kind of radical stabilizer in an Example, and an extraction rate increase rate. It is a graph which shows the relationship between the addition amount of the radical stabilizer with respect to coal on the anhydrous carbon reference | standard in an Example, and an extraction rate increase rate.

Hereinafter, embodiments of the method for producing ashless coal and the apparatus for producing ashless coal according to the present invention will be described.

[First Embodiment]
The apparatus for producing ashless coal shown in FIG. 1 mainly includes a heating unit 1, an elution unit 2, a solid-liquid separation unit 3, a first solvent separation unit 4, and a second solvent separation unit 5.

[Heating section]
The heating unit 1 includes a solvent tank 11, a pump 12, a preheater 13, and a feeder 14 that supplies coal and a radical stabilizer. The heating unit 1 also includes a transport pipe 15 that transports the solvent in the solvent tank 11 to the elution unit 2.

<Solvent tank>
The solvent tank 11 stores a solvent to be mixed with coal.

The solvent is not particularly limited as long as it dissolves coal. For example, a bicyclic aromatic compound derived from coal is preferably used. Since this bicyclic aromatic compound has a basic structure similar to the structural molecule of coal, it has a high affinity with coal and can obtain a relatively high extraction rate. Examples of the bicyclic aromatic compound derived from coal include methyl naphthalene oil and naphthalene oil, which are distilled oils of by-products when carbon is produced by carbonization to produce coke.

The boiling point of the solvent is not particularly limited. For example, the lower limit of the boiling point of the solvent is preferably 180 ° C., more preferably 230 ° C. On the other hand, the upper limit of the boiling point of the solvent is preferably 300 ° C and more preferably 280 ° C. If the boiling point of the solvent is less than the above lower limit, the solvent is likely to volatilize, and it may be difficult to adjust and maintain the mixing ratio of coal and solvent in the slurry. Conversely, if the boiling point of the solvent exceeds the upper limit, separation of the solvent-soluble component from the solvent becomes difficult, and the solvent recovery rate may be reduced.

<Pump>
The pump 12 is disposed in the transport pipe 15 and transports the solvent in the solvent tank 11 to the elution unit 2.

The type of the pump 12 is not particularly limited as long as the solvent can be pumped to the elution part 2 through the transport pipe 15, and for example, a positive displacement pump or a non-positive displacement pump can be used. More specifically, a diaphragm pump, a tube diaphragm pump, or the like can be used as the positive displacement pump, and a spiral pump or the like can be used as the non-positive displacement pump.

The lower limit of the pressure (the internal pressure of the conveying pipe 15) when the solvent is pumped to the elution part 2 by the pump 12 is preferably 1.1 MPa, and more preferably 1.5 MPa. On the other hand, the upper limit of the internal pressure of the transport pipe 15 is preferably 5 MPa, and more preferably 4 MPa. If the internal pressure of the transport pipe 15 is less than the lower limit, the power of stirring the coal when the coal is supplied to the solvent being transported, which will be described later, becomes weak, so that the coal may not be sufficiently dissolved. Conversely, if the internal pressure of the transport pipe 15 exceeds the above upper limit, the effect of improving coal dissolution obtained with respect to an increase in the cost of manufacturing equipment for ensuring the pressure resistance required for the heating unit 1 may be insufficient. There is.

Moreover, although the said solvent conveyed by the pump 12 may be conveyed in a laminar flow state, it is good to be conveyed in a turbulent flow state. By transporting the solvent in a turbulent state in this way, the force with which the solvent stirs the coal at the time of supplying the coal to the solvent being transported is increased, so that the coal is easily mixed with the solvent and the dissolution of the coal is promoted. The Here, the “laminar flow state” means a state where the Reynolds number Re is less than 2100, and the “turbulent state” means a state where the Reynolds number Re is 2100 or more, more preferably, the Reynolds number Re is 4000 or more.

The lower limit of the flow rate of the solvent conveyed by the pump 12 is preferably 0.5 m / sec, and more preferably 1 m / sec. On the other hand, the upper limit of the flow rate of the solvent is preferably 10 m / sec, and more preferably 5 m / sec. When the flow rate of the solvent is less than the above lower limit, the power of stirring the coal when the coal is supplied to the solvent being transported becomes weak, so that the dissolution of coal may be insufficient. On the contrary, when the flow rate of the solvent exceeds the upper limit, the effect of improving coal dissolution obtained for the cost increase for making the pump 12 strong may be insufficient.

<Preheater>
Although the preheater 13 will not be specifically limited if the solvent which passes the inside of the preheater 13 can be heated, For example, a resistance heating type heater and an induction heating coil are mentioned. Moreover, you may heat using a heat medium. For example, a heating pipe is arranged around the solvent flow path that passes through the preheater 13, and the solvent passing through the preheater 13 can be heated by supplying a heating medium such as steam or oil to the heating pipe. .

The lower limit of the temperature of the solvent after heating by the preheater 13 is preferably 300 ° C, more preferably 350 ° C. On the other hand, the upper limit of the temperature of the solvent is not particularly limited as long as it is a temperature at which elution is possible, but is preferably 480 ° C and more preferably 450 ° C. If the temperature of the solvent is lower than the lower limit, the binding between the molecules constituting the coal in the elution part 2 cannot be sufficiently weakened, and the elution rate may decrease. On the contrary, when the temperature of the solvent exceeds the upper limit, the amount of heat for maintaining the temperature of the solvent becomes unnecessarily large, which may increase the manufacturing cost.

The lower limit of the heating rate by the preheater 13 is preferably 10 ° C / min, and more preferably 20 ° C / min. On the other hand, the upper limit of the heating rate is preferably 100 ° C./min, more preferably 50 ° C./min. If the heating rate is less than the lower limit, it takes time to heat the solvent to a predetermined temperature, which may reduce the production efficiency of ashless coal. On the other hand, when the heating rate exceeds the upper limit, energy for heating, costs for manufacturing equipment, and the like may increase unnecessarily.

The heating time by the preheater 13 is not particularly limited, but can be set to, for example, 10 minutes or more and 30 minutes or less because of the relationship between the temperature and the heating rate described above.

<Supplyer>
The supplier 14 supplies coal and a radical stabilizer to the transport pipe 15. As the supply device 14, a known hopper such as a normal pressure hopper used in a normal pressure state or a pressure hopper used in a normal pressure state or a pressurized state can be used. The coal and radical stabilizer are mixed and charged into the hopper.

(coal)
As the coal supplied from the supply device 14, various quality coals can be used. As the coal, for example, bituminous coal having a high extraction rate of ashless coal or cheaper inferior quality coal (subbituminous coal or lignite) is preferably used. Further, when coal is classified by particle size, finely pulverized coal is preferably used. Here, “finely pulverized coal” means, for example, coal in which the mass ratio of coal having a particle size of less than 1 mm to the mass of the entire coal is 80% or more. Moreover, lump coal can also be used as coal supplied from the supply device 14. Here, “coal” means, for example, coal in which the mass ratio of coal having a particle size of 5 mm or more to the mass of the entire coal is 50% or more. Since the lump coal has a larger coal particle size than the finely pulverized coal, the separation in the solid-liquid separation unit 3 described later can be made efficient. Here, “particle size (particle size)” refers to a value measured in accordance with the JIS-Z8815 (1994) general screening test rules. For sorting according to the particle size of coal, for example, a metal mesh screen defined in JIS-Z8801-1 (2006) can be used.

Further, from the viewpoint of shortening the elution time, it is preferable to use coal containing a large amount of inferior coal as coal supplied from the feeder 14. In this case, the lower limit of the proportion of inferior coal in the whole coal to be supplied is preferably 80% by mass, and more preferably 90% by mass. There exists a possibility that the time which elutes a solvent soluble component may become long that the ratio of the inferior quality coal contained in the coal to supply is less than the said minimum.

The lower limit of the carbon content of the inferior coal is preferably 70% by mass. On the other hand, the upper limit of the carbon content of the inferior coal is preferably 85% by mass, and more preferably 82% by mass. There exists a possibility that the elution rate of a solvent soluble component may fall that the carbon content rate of the said inferior coal is less than the said minimum. Conversely, if the carbon content of the inferior coal exceeds the upper limit, the cost of the supplied coal may increase.

(Radical stabilizer)
The radical stabilizer is mixed with the coal and charged into the feeder 14.

Examples of radical stabilizers include amine stabilizers and phenol stabilizers, among which amine stabilizers such as amines and ammonium salts are preferred, and amines are particularly preferred. The amine is preferably a monoamine such as octadecylamine, a diamine such as N-alkyl-1,3-diaminopropane, or a triamine such as beef tallow dipropylenetriamine, and more preferably a monoamine.

As a minimum of the addition amount of the above-mentioned radical stabilizer to coal on an anhydrous carbon basis, 0.045 mmol / g is preferred and 0.15 mmol / g is more preferred. On the other hand, the upper limit of the amount of radical stabilizer added is preferably 0.4 mmol / g, more preferably 0.22 mmol / g. If the added amount of the radical stabilizer is less than the lower limit, the effect of improving the extraction rate of ashless coal may be insufficient. Conversely, if the amount of the radical stabilizer added exceeds the upper limit, the cost of the radical stabilizer may be too high for the effect of improving the extraction rate of ashless coal.

¡The mixture of coal and radical stabilizer should be preheated. By preheating the mixture, it is possible to prevent the temperature of the slurry from being lowered when the mixture is supplied to the transport pipe 15 and mixed with the solvent. Although it does not specifically limit as preheating temperature of the said mixture, For example, it can be 200 degreeC or more and 300 degrees C or less.

It should be noted that a mixture obtained by mixing a solvent into a slurry may be used as the mixture supplied from the supply device 14 to the transport pipe 15. By supplying the slurry mixture from the supply device 14 to the transport pipe 15, the coal and the radical stabilizer are easily mixed with the solvent in the transport pipe 15, and the coal can be dissolved more quickly.

The lower limit of the coal concentration on the basis of anhydrous carbon in the slurry is preferably 20% by mass, more preferably 30% by mass. On the other hand, the upper limit of the coal concentration is preferably 70% by mass, and more preferably 60% by mass. If the coal concentration is less than the above lower limit, the elution amount of solvent-soluble components eluted in the elution part 2 to be described later decreases with respect to the slurry processing amount, which may reduce the production efficiency of ashless coal. . Conversely, if the coal concentration exceeds the upper limit, the effect of facilitating the mixing of coal and solvent by slurrying may be insufficient.

<Transport pipe>
The transport pipe 15 transports the solvent in the solvent tank 11 to the elution unit 2. Further, the mixture of coal and radical stabilizer supplied from the supply device 14 to the transport pipe 15 is mixed with the heated solvent flowing in the transport pipe 15 in the transport pipe 15 and rapidly heated. Here, “rapid temperature rise” means heating at a heating rate of about 10 ° C./second or more and 500 ° C./second or less, for example. As a result, the temperature of the slurry, which is a mixture of the solvent, the coal, and the radical stabilizer, becomes a relatively uniform temperature within a few seconds to a few dozen seconds after the coal and the radical stabilizer are added. The temperature of the slurry is lower than the temperature of the solvent after heating by the sensible heat of coal, for example, about 350 ° C. or more and 420 ° C. or less.

The lower limit of the coal concentration on the basis of anhydrous carbon in the slurry is preferably 5% by mass, and more preferably 10% by mass. On the other hand, the upper limit of the coal concentration is preferably 40% by mass, and more preferably 30% by mass. If the coal concentration is less than the above lower limit, the elution amount of solvent-soluble components eluted in the elution part 2 to be described later decreases with respect to the slurry processing amount, which may reduce the production efficiency of ashless coal. . Conversely, if the coal concentration exceeds the upper limit, the solvent-soluble component is saturated in the solvent, and the elution rate of the solvent-soluble component may be reduced.

[Elution part]
The elution part 2 elutes a coal component soluble in a solvent from the coal in the slurry obtained in the heating part 1. The elution part 2 has an extraction tank 21.

The slurry is supplied to the extraction tank 21 from the transport pipe 15. In the extraction tank 21, coal components soluble in the solvent are eluted from the coal while maintaining the temperature of the slurry. The extraction tank 21 has a stirrer 21a. The elution can be promoted by stirring the slurry with the stirrer 21a.

The lower limit of the internal pressure of the extraction tank 21 is preferably 1.1 MPa, and more preferably 1.5 MPa. On the other hand, the upper limit of the internal pressure of the extraction tank 21 is preferably 5 MPa, and more preferably 4 MPa. When the internal pressure of the extraction tank 21 is less than the lower limit, the solvent is reduced by evaporation, and there is a possibility that the coal may not be sufficiently dissolved. On the contrary, when the internal pressure of the extraction tank 21 exceeds the upper limit, there is a possibility that the improvement effect of coal dissolution obtained for the cost increase for maintaining the pressure is insufficient.

In addition, the elution time in the elution part 2 is not particularly limited, but can be 10 minutes or more and 70 minutes or less from the viewpoint of the extraction amount of solvent-soluble components and the extraction efficiency.

The slurry from which the soluble coal component is eluted in the elution unit 2 is sent to the solid-liquid separation unit 3 through the supply pipe.

[Solid-liquid separation unit]
The solid-liquid separation unit 3 separates the solution obtained by dissolving the coal component obtained in the elution unit 2 in the solvent and the solid concentrate containing the solvent-insoluble component from the slurry. The solvent-insoluble component refers to an extraction residue that is mainly composed of ash and insoluble coal that are insoluble in the extraction solvent, and also includes the extraction solvent.

The separation in the solid-liquid separation unit 3 can be performed by, for example, a gravity sedimentation method. Here, the gravity sedimentation method is a separation method in which a solid content is settled by using gravity in a sedimentation tank to perform solid-liquid separation. When separation is performed by the gravity sedimentation method, a solution containing a solvent-soluble component is accumulated at the upper part of the solid-liquid separation unit 3. This solution is filtered using a filter unit as necessary, and then discharged to the first solvent separation unit 4. On the other hand, the solid concentrate containing the solvent-insoluble component is collected at the lower part of the solid-liquid separation unit 3 and discharged to the second solvent separation unit 5.

Further, when separation is performed by the gravity sedimentation method, the liquid containing the solvent-soluble component and the solid content containing the solvent-insoluble component are discharged from the settling tank while continuously supplying the slurry into the solid-liquid separation unit 3. be able to. Thereby, continuous solid-liquid separation processing becomes possible.

The time for maintaining the slurry in the solid-liquid separation unit 3 is not particularly limited, but can be, for example, 30 minutes or more and 120 minutes or less, and sedimentation separation in the solid-liquid separation unit 3 is performed within this time. In addition, when using lump coal as coal, since sedimentation separation is made efficient, the time which maintains a slurry in the solid-liquid separation part 3 can be shortened.

It is preferable to heat and pressurize the solid-liquid separation unit 3. As a minimum of heating temperature in solid-liquid separation part 3, 300 ° C is preferred and 350 ° C is more preferred. On the other hand, as an upper limit of the heating temperature in the solid-liquid separation part 3, 420 degreeC is preferable and 400 degreeC is more preferable. If the heating temperature is less than the lower limit, the solvent-soluble component may reprecipitate and the separation efficiency may be reduced. Conversely, if the heating temperature exceeds the upper limit, the operating cost for heating may increase.

Moreover, as a minimum of the pressure in the solid-liquid separation part 3, 1 MPa is preferable and 1.4 MPa is more preferable. On the other hand, the upper limit of the pressure is preferably 3 MPa, more preferably 2 MPa. If the pressure is less than the lower limit, the solvent-soluble component may reprecipitate and the separation efficiency may be reduced. Conversely, when the pressure exceeds the upper limit, the operating cost for pressurization may increase.

In addition, as a method of isolate | separating the said solution and solid content concentrate, it is not restricted to a gravity sedimentation method, For example, you may use the filtration method and the centrifugation method. When a filtration method or a centrifugation method is used as the solid-liquid separation method, a filter, a centrifuge, or the like is used as the solid-liquid separation unit 3.

[First solvent separation unit]
The first solvent separation unit 4 evaporates the solvent from the solution separated by the solid-liquid separation unit 3. Ashless coal HPC is obtained by evaporating and separating the solvent. The first solvent separation unit 4 can be called an evaporation separation unit.

The ashless coal HPC obtained in this way exhibits a higher calorific value than, for example, coke raw material coal. Furthermore, ashless coal has a significantly improved softening and melting property, which is a particularly important quality as a raw material for iron-making coke, and exhibits fluidity far superior to, for example, raw material coal. Therefore, ashless coal can also be used as coal blended with coke raw materials.

As a method for evaporating and separating the solvent, a separation method including a general distillation method using an evaporative separator or an evaporation method (spray drying method or the like) can be used.

The solvent evaporated in the first solvent separation unit 4 may be liquefied by, for example, a heat exchanger, supplied to the heating unit 1, and used as a solvent to be mixed with coal and a radical stabilizer. Thus, the recycling cost of a solvent can reduce the manufacturing cost of ashless coal.

[Second solvent separation unit]
The second solvent separation unit 5 evaporates and separates the solvent from the solid concentrate separated by the solid-liquid separation unit 3 to obtain by-product coal RC.

By-product charcoal RC does not show softening and melting properties, but the oxygen-containing functional groups are eliminated. Therefore, by-product coal RC does not inhibit the softening and melting properties of other coals included in this blended coal when used as a blended coal. Therefore, this byproduct charcoal RC can be used, for example, as a part of the blended coal of the coke raw material. Moreover, you may utilize byproduct coal RC as a fuel similarly to general coal.

As a method for separating the solvent from the solid concentrate, a general distillation method or evaporation method (e.g., spray drying method) using an evaporation separator is used, as in the separation method of the first solvent separation unit 4. it can.

Note that the solvent evaporated in the second solvent separation unit 5 may be liquefied by, for example, a heat exchanger, supplied to the heating unit 1, and used as a solvent to be mixed with coal and a radical stabilizer. Thus, the recycling cost of a solvent can reduce the manufacturing cost of ashless coal.

[Production method of ashless coal]
The method for producing ashless coal includes a heating step, an elution step, a separation step, a first evaporation step, and a second evaporation step. The said ashless coal manufacturing method can be performed using the manufacturing apparatus of ashless coal of FIG.

<Heating process>
In the heating step, the mixture of coal, radical stabilizer and solvent is heated. The heating process includes a solvent heating process, a solvent transport process, and a supply process for supplying coal and a radical stabilizer.

In the solvent heating step, the solvent is heated. Specifically, the solvent stored in the solvent tank 11 is caused to flow to the transport pipe 15 by the pump 12, and the solvent flowing in the transport pipe 15 is heated while passing through the preheater 13.

In the solvent transport step, the solvent heated in the solvent heating step is transported to the elution step. Specifically, the solvent is supplied to the elution part 2 through the transport pipe 15.

In the supply step, coal and a radical stabilizer are supplied to the solvent in the solvent transport step. Specifically, coal and a radical stabilizer are supplied from the feeder 14 to the conveying pipe 15 through which the heated solvent flows, and the coal, the radical stabilizer and the solvent are mixed to form a slurry. The coal and radical stabilizer supplied to the transport pipe 15 are rapidly heated by the solvent, and the solvent flowing through the transport pipe 15 stirs the coal, so that the coal is easily dissolved and the solvent and the coal are well mixed. A slurry is obtained.

The lower limit of the coal heating rate in the supplying step is preferably 600 ° C./min, and more preferably 700 ° C./min. There exists a possibility that the improvement effect of the extraction rate of ashless coal by a radical stabilizer may be insufficient that the said temperature increase rate is less than the said minimum. On the other hand, the upper limit of the heating rate is not particularly limited, but can be 30000 ° C./min. When the temperature increase rate exceeds the upper limit, the cost for temperature increase may increase unnecessarily. In addition, the said temperature increase rate can be adjusted with the heating temperature of the solvent in the said solvent heating process.

<Elution process>
In the elution step, a coal component soluble in a solvent is eluted from the coal in the slurry obtained in the heating step. Specifically, the slurry prepared in the heating step is supplied to the extraction tank 21, and the solvent-soluble component is extracted while being held at a predetermined temperature while being stirred by the stirrer 21a.

<Separation process>
In the separation step, the slurry eluted in the elution step is separated into a liquid component containing a solvent-soluble component and a solid content concentrate containing a solvent-insoluble component. Specifically, the slurry discharged from the extraction tank 21 is supplied to the solid-liquid separation unit 3, and the slurry supplied into the solid-liquid separation unit 3 is separated into the liquid component and the solid content concentrate by, for example, gravity sedimentation. To do.

<First evaporation step>
In the first evaporation step, the solvent is evaporated from the solution separated in the separation step. Specifically, the solution separated by the solid-liquid separation unit 3 is supplied to the first solvent separation unit 4, and the solvent is evaporated by the first solvent separation unit 4. This separates the solution into solvent and ashless coal.

<Second evaporation step>
In the second evaporation step, the solvent is evaporated from the solid content concentrate separated in the separation step. Specifically, the solid concentrate separated by the solid-liquid separation unit 3 is supplied to the second solvent separation unit 5, and the solvent is evaporated by the second solvent separation unit 5 to separate the solvent and by-product coal. .

[advantage]
In the said ashless coal manufacturing apparatus and the said ashless coal manufacturing method, a radical stabilizer is added to the slurry before heating and extracting a solvent soluble component. Since this radical stabilizer can suppress polymerization due to polycondensation of coal radicals caused by heating the slurry, it is possible to increase the soluble components of coal to be eluted. Therefore, the extraction rate of ashless coal can be increased by using the ashless coal production apparatus and the ashless coal production method.

Moreover, in the said ashless coal manufacturing apparatus and the said ashless coal manufacturing method, while supplying coal to the heated solvent in conveyance, coal can be heated up rapidly and coal and a solvent by the flow of a solvent. And can be stirred. Thereby, coal can be melt | dissolved in a solvent in a short time. Further, by supplying a radical stabilizer together with coal, it is possible to effectively inhibit the polymerization of coal radicals, thereby further increasing the extraction rate of ashless coal.

[Second Embodiment]
The heating unit 10 in FIG. 2 is used in place of the heating unit 1 of the ashless coal manufacturing apparatus in FIG. 1. The heating unit 10 in FIG. 2 includes a solvent tank 11, a feeder 14, a mixing unit 16, a pump 17, and a temperature raising unit 18. The solvent tank 11 and the supply device 14 are the same as those in the ashless coal production apparatus of FIG.

<Mixing section>
The mixing unit 16 mixes the solvent supplied from the solvent tank 11 with the coal and radical stabilizer supplied from the supplier 14.

As the mixing unit 16, a preparation tank 19 can be used. The preparation tank 19 is supplied with the coal, radical stabilizer and solvent through a supply pipe. In the preparation tank 19, the supplied coal, radical stabilizer and solvent are mixed to prepare a slurry. Moreover, the said preparation tank 19 has the stirrer 19a, and maintains the mixing state of a slurry by hold | maintaining the mixed slurry, stirring with the stirrer 19a.

In addition, the slurry prepared in the preparation tank 19 of the mixing unit 16 is sent to the temperature raising unit 18 through the supply pipe.

<Pump>
The pump 17 is disposed in a supply pipe that supplies the slurry from the mixing unit 16 to the temperature raising unit 18, and pumps the slurry stored in the preparation tank 19 to the temperature raising unit 18.

The type of the pump 17 is not particularly limited as long as it can pump the slurry to the temperature raising unit 18 through the supply pipe, and for example, a positive displacement pump or a non-positive displacement pump can be used. Examples of the positive displacement pump include a diaphragm pump and a tube diaphragm pump, and examples of the non-positive displacement pump include a spiral pump.

<Temperature riser>
The temperature raising unit 18 raises the temperature of the slurry obtained in the mixing unit 16.

The temperature raising unit 18 is not particularly limited as long as it can raise the temperature of the slurry passing through the inside, and examples thereof include a resistance heating heater and an induction heating coil. Further, the temperature raising unit 18 may be configured to raise the temperature using a heat medium. For example, the temperature raising unit 18 includes a heating pipe disposed around the flow path of the slurry passing through the inside, and the heating pipe The slurry may be configured to be heated by supplying a heating medium such as steam or oil.

As a minimum of the temperature of the slurry after temperature rising by temperature rising part 18, 300 ° C is preferred and 360 ° C is more preferred. On the other hand, the upper limit of the temperature of the slurry is preferably 420 ° C., more preferably 400 ° C. If the temperature of the slurry is less than the lower limit, the bonds between the molecules constituting the coal cannot be sufficiently weakened, and the elution rate may decrease. On the contrary, when the temperature of the slurry exceeds the upper limit, the amount of heat for maintaining the temperature of the slurry becomes unnecessarily large, which may increase the production cost of the porous carbon particles.

[Production method of ashless coal]
The method for producing ashless coal includes a heating step, an elution step, a separation step, a first evaporation step, and a second evaporation step. The ashless coal production method can be performed using an ashless coal production apparatus having the heating unit 10 of FIG. In addition, since an elution process, a separation process, a 1st evaporation process, and a 2nd evaporation process can be performed similarly to the manufacturing method of ashless coal of 1st Embodiment, only a heating process is demonstrated here.

<Heating process>
In the heating step, the mixture of coal, radical stabilizer and solvent is heated. The heating step includes a mixing step and a temperature raising step.

In the mixing process, coal, radical stabilizer and solvent are mixed. Specifically, coal and radical stabilizer supplied from the supply device 14 and the solvent supplied from the solvent tank 11 are mixed in the preparation tank 19 of the mixing unit 16 to form a slurry.

In the temperature raising step, the temperature of the slurry obtained in the mixing step is raised. Specifically, the slurry is supplied to the temperature raising unit 18 by the pump 17 to raise the temperature of the slurry.

[advantage]
In the ashless coal production apparatus and the ashless coal production method, since the temperature of the slurry is increased after mixing the radical stabilizer, polymerization of coal radicals can be effectively suppressed. The extraction rate can be further increased.

[Other Embodiments]
In addition, the manufacturing apparatus of ashless coal and the manufacturing method of ashless coal of this invention are not limited to the said embodiment.

In the above embodiment, the configuration in which a mixture in which coal and a radical stabilizer are mixed in advance is supplied from a feeder, but the coal and the radical stabilizer may be supplied separately.

Moreover, although the case where the 2nd evaporation process was provided as a manufacturing method of ashless coal was demonstrated in the said embodiment, for example, when not using by-product coal, this 2nd evaporation process is omissible. When not performing a 2nd evaporation process, the manufacturing apparatus of ashless coal does not need to be equipped with a 2nd solvent separation part.

In the first embodiment, the case where the preheater is disposed on the downstream side of the pump as the heating unit has been described, but the arrangement order of the pump and the preheater may be reversed.

In the said 2nd Embodiment, although the mixing part of the manufacturing apparatus of ashless coal demonstrated the structure which has a preparation tank, if not only this structure but mixing of a solvent, coal, and a radical stabilizer can be performed, a preparation tank will be abbreviate | omitted. May be. For example, when the above mixing is completed by a line mixer, the preparation tank may be omitted and a line mixer may be provided between the supply pipe and the temperature raising unit.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

40g of bituminous coal was prepared as coal. In addition, the said coal was grind | pulverized and used so that the ratio of coal with a particle diameter of less than 1 mm with respect to all the coal might be 90 mass% or more. In addition, 240 g of 1-methylnaphthalene was prepared as an ashless coal extraction solvent. This coal and solvent were mixed to prepare a slurry.

2 g of octadecylamine, which is a monoamine, was prepared as a radical stabilizer and added to the slurry and mixed.

The slurry was put into an autoclave having a capacity of 500 cc having a stainless steel filter, and the temperature was raised to 380 ° C. under a pressure condition of 2 MPa. And it stirred for 40 minutes, keeping temperature at 380 degreeC, and the coal component soluble in a solvent was eluted from coal.

The filtration was carried out with the above extraction temperature, the mass of the filter residue (solvent insoluble component) was measured, and the proportion of coal component soluble in the solvent, that is, the extraction rate was calculated.

The same treatment was performed with the addition amount of monoamine being 0 g, 0.5 g, 1 g, and 4 g. Note that “the amount of monoamine added is 0 g” means that no monoamine is added.

Based on the extraction rate when the addition amount of monoamine was 0 g, the increase rate (mass%) of the extraction rate at other addition amounts was calculated. The results are shown in FIG. The “increase rate” is an amount calculated by (Y−X) / X × 100, where X is the extraction rate when the addition amount is 0 g, and Y is the extraction rate under the condition for calculating the increase rate. It is. Moreover, in FIG. 3, the horizontal axis is converted to the amount of the radical stabilizer added to coal (mmol / g) based on anhydrous carbon.

From the result of FIG. 3, the effect is recognized when the addition amount is 0.045 mmol / g or more (the increase in extraction rate is 3% or more), and is proportional to the addition amount of monoamine up to about 0.4 mmol / g. It can be seen that the extraction rate increases.

In addition, with the amount of radical stabilizer added fixed at 2 g, the types of radical stabilizers are primary monoamine octadecylamine (amine A), secondary monoamine dioctadecylamine (amine B), and quaternary ammonium. The same treatment was carried out as the salt dialkyldimethylammonium chloride (amine C), primary diamine N-alkyl-1,3-diaminopropane (amine D), and primary triamine tallow dipropylene triamine (amine E). The extraction rate increase rate (mass%) was calculated. The results are shown in FIG. FIG. 5 is a graph showing the above results based on the amount (mol amount) of the radical stabilizer added to the coal based on anhydrous carbon.

4 and 5 show that the extraction rate increases with any radical stabilizer. In particular, when monoamine is used as the radical stabilizer, it can be seen that the rate of increase in the extraction rate is high. Moreover, it turns out that an extraction rate can be raised by increasing the addition amount of the radical stabilizer with respect to coal on an anhydrous coal basis. From the above, it is considered that the extraction rate can be increased by adding a radical stabilizer.

DESCRIPTION OF SYMBOLS 1,10 Heating part 11

Solvent tank

12, 17 Pump 13 Preheater 14 Feeder 15 Conveying pipe 16 Mixing part 18 Temperature rising part 19 Preparation tank 19a Stirrer 2 Elution part 21 Extraction tank 21a Stirrer 3 Solid-liquid separation part 4 1st solvent Separator 5 Second solvent separator

Claims

Heating a mixture of coal, radical stabilizer and solvent;
A step of eluting components soluble in the solvent from the coal in the slurry obtained in the heating step;
Separating the slurry after elution in the elution step into a liquid component containing a solvent-soluble component and a solvent-insoluble component;
And a step of evaporating the solvent from the liquid component separated in the separation step.
The heating step is
Mixing coal, radical stabilizer and solvent;
The method for producing ashless coal according to claim 1, further comprising: raising the temperature of the slurry obtained in the mixing step.
The heating step is
Heating the solvent;
Conveying the solvent heated in the solvent heating step to the elution step;
The method for producing ashless coal according to claim 1, further comprising: supplying coal and a radical stabilizer to the solvent in the solvent conveying step.
The method for producing ashless coal according to claim 3, wherein the heating temperature of the solvent in the solvent heating step is adjusted so that the heating rate of the coal in the supplying step is 600 ° C / min or more.
The method for producing ashless coal according to claim 1, wherein the amount of the radical stabilizer added to coal on an anhydrous coal basis is 0.045 mmol / g or more and 0.4 mmol / g or less.
The method for producing ashless coal according to any one of claims 1 to 5, wherein the radical stabilizer is an amine or an ammonium salt.
The method for producing ashless coal according to claim 6, wherein the amine is monoamine, diamine or triamine.
A heating section for heating a mixture of coal, radical stabilizer and solvent;
An elution part for eluting components soluble in the solvent from the coal in the slurry obtained in the heating part;
A solid-liquid separation part for separating the slurry after elution in the elution part into a liquid component containing a solvent-soluble component and a solvent-insoluble component;
An ashless coal manufacturing apparatus, comprising: an evaporation separation unit that evaporates a solvent from the liquid component separated by the solid-liquid separation unit.