JP2018009066A - Production method of ashless coal and production equipment for ashless coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of ashless coal allowing for reduction in production cost of ashless coal by reducing cooling water needed for cooling ashless coal and reusing heat quantity of ashless coal.SOLUTION: The production method of ashless coal comprises s a mixing step of mixing coal and a solvent, a step of heating a slurry obtained in the mixing step, a step of separating a solution in which the coal component obtained in the heating step is dissolved in a solvent from a slurry, a step of vaporizing the solvent from the solution separated in the separation step, a step of heat exchanging liquid ashless coal obtained in the vaporizing step with a cooling medium, the cooling medium in the heat exchange step being used as the solvent in the mixing step. The production method of ashless coal preferably further comprises a step of recovering the solvent in the heating step, the separation step or the vaporization step and the solvent recovered in the recovering step is preferably used as the cooling medium in the heat exchange step.SELECTED DRAWING: Figure 1

Description

  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 fuel or chemicals for thermal power generation and boilers, and as one of environmental measures, development of a technology for efficiently removing 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 2009-227718). 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. Further, this method includes a solution separation step for 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 an ashless by separating the solvent from the solution separated in the solution separation step. And an ashless coal acquisition step for obtaining charcoal.

  The ashless coal obtained in the ashless coal acquisition step is in a high temperature state at the stage of separating the solvent and has fluidity. In order to safely recover the ashless coal as a product, it is necessary to cool and solidify the high temperature ashless coal.

  An indirect cooling method using water is generally used for cooling the ashless coal. In the indirect cooling method, for example, ashless coal is supplied into the screw conveyor, and the ashless coal is cooled by supplying cooling water to the outer wall or shaft of the screw conveyor. In addition, this cooling water is sent to the cooling tower equipment and reused after being cooled. From the viewpoint of the cooling cost at the time of reuse, the temperature difference between the supplied cooling water and the recovered cooling water. Is set relatively low.

  However, if the temperature difference between the cooling water supplied and the recovered cooling water is set low, the amount of heat that can be recovered by the cooling water per unit amount is limited. For this reason, in order to cool the ashless coal which has a large calorie | heat amount at high temperature, it is necessary to circulate a comparatively large amount of cooling water. Moreover, the calorie | heat amount of the ashless coal collect | recovered with cooling water is discarded by a cooling tower installation, without being reused. For this reason, reduction of the cooling water required for cooling of ashless coal and reuse of the calorie | heat amount of ashless coal are desired from a viewpoint of manufacturing cost reduction.

JP 2009-227718 A

  The present invention has been made based on the above-described circumstances, and can reduce the production cost of ashless coal by reducing the cooling water necessary for cooling the ashless coal and reusing the heat of the ashless coal. It aims at providing the manufacturing method of ash coal, and the manufacturing apparatus of ashless coal.

  The invention made in order to solve the above problems is a slurry mixing step of mixing coal and a solvent, a step of heating the slurry obtained in the mixing step, and a solution in which the coal component obtained in the heating step is dissolved in the solvent. A step of evaporating the solvent from the solution separated in the separation step, and a step of heat-exchanging the liquid ashless coal obtained in the evaporation step with a cooling medium. It is a manufacturing method of ashless coal which uses a cooling medium as a solvent in the above-mentioned mixing process.

  In the method for producing ashless coal, a cooling medium that cools ashless coal in the heat exchange step is used as a solvent in the mixing step. Since the ashless coal manufacturing method cools the ashless coal with the solvent used in the mixing step as described above, the amount of cooling water used can be reduced without newly introducing a cooling medium. Moreover, since the manufacturing method of the said ashless coal uses the cooling medium which collect | recovered the calorie | heat amount of ashless coal in the heat exchange process as a solvent in a mixing process, the calorie | heat amount of ashless coal is reused and the slurry obtained by a mixing process The temperature of is increased. This can reduce the amount of heat required for heating in the heating step. Therefore, the production cost of ashless coal can be reduced by using the method for producing ashless coal.

  A step of recovering the solvent in the heating step, the separation step, or the evaporation step may be further provided, and the solvent recovered in the recovery step may be used as a cooling medium in the heat exchange step. By recovering the solvent recovered in the heating step, the separation step, or the evaporation step and using it as a cooling medium in the heat exchange step, the amount of cooling medium to be newly supplied can be reduced.

  Another invention made in order to solve the above problems is that a mixing unit for mixing coal and a solvent, a heating unit for heating slurry obtained in the mixing unit, and a coal component obtained in the heating unit are dissolved in the solvent. A solid-liquid separation unit for separating the solution from the slurry, a solvent separation unit for evaporating the solvent from the solution separated by the solid-liquid separation unit, and a liquid ashless coal obtained by the solvent separation unit as a cooling medium and a heat An apparatus for producing ashless coal, comprising: a heat exchanging part to be exchanged; and a cooling medium delivery channel for supplying a cooling medium after heat exchange in the heat exchanging part to the mixing part.

  Since the ashless coal manufacturing apparatus includes a cooling medium delivery channel that supplies the cooling medium after heat exchange in the heat exchange unit to the mixing unit, the cooling medium for cooling the ashless coal is used as a solvent in the mixing unit. Can be used. For this reason, the usage-amount of cooling water can be reduced by using the said ashless coal manufacturing apparatus, without introduce | transducing a cooling medium newly. Moreover, since the said ashless coal manufacturing apparatus can use the cooling medium which collect | recovered the calorie | heat amount of ashless coal as a solvent mixed in a mixing part, the calorie | heat amount of ashless coal can be reused for heating of a slurry. Therefore, the production cost of ashless coal can be reduced by using the ashless coal production 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. The “ash” means a value measured according to JIS-M8812: 2004.

  As described above, the method and apparatus for producing ashless coal according to the present invention can reduce the cooling water necessary for cooling the ashless coal and reuse the heat quantity of the ashless coal. Therefore, by using the method and apparatus for producing ashless coal of the present invention, the production cost of ashless coal associated with the use of cooling water and the heat of heating of the slurry can be reduced.

It is the schematic which shows the manufacturing apparatus of the ashless coal of 1st embodiment of this invention. It is a graph which shows the temperature change of the ashless coal of comparative example 1, and cooling water. It is a graph which shows the temperature change of the ashless coal of Example 1, and a solvent. It is a graph which shows the temperature change of ashless coal of Example 2, a solvent, and cooling water. It is a graph which shows the temperature change of the ashless coal of Example 3, a solvent, and cooling water.

  Hereinafter, the embodiment of the manufacturing apparatus and manufacturing method of ashless coal concerning the present invention is explained in full detail.

[Production equipment for ashless coal]
The ashless coal production apparatus of FIG. 1 includes a coal supply unit 1, a solvent supply unit 2, a mixing unit 3, a pump 4, a heating unit 5, a solid-liquid separation unit 6, and a first solvent separation unit 7. And a second solvent separation unit 8 and a heat exchange unit 9. The ashless coal manufacturing apparatus includes a cooling medium supply channel 100 that supplies a solvent to the heat exchange unit 9 and a first solvent recovery channel that supplies the solvent recovered by the heating unit 5 to the heat exchange unit 9. 101, a second solvent recovery flow path 102 for supplying the solvent recovered by the solid-liquid separation unit 6 to the heat exchange unit 9, and a first solvent for supplying the solvent recovered by the first solvent separation unit 7 to the heat exchange unit 9. A third solvent recovery channel 103, a fourth solvent recovery channel 104 for supplying the solvent recovered by the second solvent separation unit 8 to the heat exchanging unit 9, and a cooling medium after the heat exchange by the heat exchanging unit 9 And a cooling medium delivery flow path 110 to be supplied to the unit 2.

<Coal supply department>
The coal supply unit 1 supplies coal to the mixing unit 3. As the coal supply part 1, well-known coal hoppers, such as a normal pressure hopper used in a normal pressure state, a pressure hopper used in a normal pressure state and a pressurized state, can be used.

  As coal supplied from the coal supply part 1, various quality coal can be used. For example, bituminous coal with 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 the coal supplied from the coal supply unit 1. 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 finely pulverized coal, the separation in the solid-liquid separation unit 6 described later can be made efficient. Here, “particle size (particle size)” refers to a value measured in accordance with JIS-Z8815 (1994) screening test rules. In addition, the metal net sieve prescribed | regulated to JIS-Z8801-1 (2006) can be used for the classification by the particle size of coal, for example.

  Moreover, it is preferable to use what contains many inferior quality coal as coal supplied from the coal supply part 1 from a viewpoint of shortening of elution time. As a minimum of the ratio of inferior quality coal in the whole coal to supply, 80 mass% is preferred and 90 mass% is more preferred. 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.

  In addition, as coal supplied to the mixing part 3 from the coal supply part 1, you may use the coal which mixed a small amount of solvent and made it slurry. By supplying the slurryed coal from the coal supply unit 1 to the mixing unit 3, the coal is easily mixed with the solvent in the mixing unit 3, and the coal can be dissolved more quickly. However, if the amount of the solvent to be mixed at the time of forming the slurry is large, the amount of heat for raising the temperature of the slurry to the elution temperature in the heating unit 5 becomes unnecessarily large, which may increase the manufacturing cost.

<Solvent supply unit>
The solvent supply unit 2 supplies the solvent to the mixing unit 3. The solvent supply unit 2 includes a solvent tank that stores a solvent, and supplies the solvent from the solvent tank to the mixing unit 3.

  Although the solvent mixed with coal will not be specifically limited if coal is melt | dissolved, For example, the bicyclic aromatic compound derived from coal is used suitably. 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 lower limit, the solvent is likely to volatilize, and it may be difficult to prepare 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.

  As a minimum of the temperature of the solvent in solvent supply part 2, 40 ° C is preferred and 50 ° C is more preferred. On the other hand, the upper limit of the temperature of the solvent is preferably 220 ° C, more preferably 170 ° C. When the temperature of the solvent is lower than the lower limit, the amount of heat for raising the slurry to the elution temperature in the heating unit 5 described later increases, and thus the production cost may increase. On the other hand, when the temperature of the solvent exceeds the upper limit, the solvent is likely to volatilize, which may make it difficult to prepare and maintain the mixing ratio of coal and solvent in the slurry.

<Mixing section>
The mixing unit 3 mixes the coal supplied from the coal supply unit 1 and the solvent supplied from the solvent supply unit 2.

  The mixing unit 3 has a preparation tank 31. The solvent and coal are supplied to the preparation tank 31 through a supply pipe. The preparation tank 31 stores a slurry in which the supplied solvent and coal are mixed. Moreover, the said preparation tank 31 has the stirrer 31a. The preparation tank 31 maintains the mixed state of the slurry by holding the mixed slurry while stirring with the stirrer 31a.

  As a minimum of coal concentration on the basis of anhydrous coal in the slurry in preparation tank 31, 10 mass% is preferred and 13 mass% is more preferred. On the other hand, the upper limit of the coal concentration is preferably 25% by mass, and more preferably 20% by mass. If the coal concentration is less than the above lower limit, the elution amount of solvent-soluble components eluted in the heating unit 5 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.

  The slurry prepared in the preparation tank 31 of the mixing unit 3 is sent to the heating unit 5 through a supply pipe.

<Pump>
The pump 4 is disposed in a supply pipe that supplies slurry from the mixing unit 3 to the heating unit 5. The pump 4 pumps the slurry stored in the preparation tank 31 of the mixing unit 3 to the heating unit 5 through a supply pipe.

  The type of the pump 4 is not particularly limited as long as the slurry can be pumped to the heating unit 5 through a supply pipe. 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.

<Heating section>
The heating unit 5 heats the slurry obtained in the mixing unit 3. By this heating, the coal component soluble in the solvent can be eluted from the coal. The heating unit 5 includes a preheater 51 and an extraction tank 52.

  The preheater 51 heats the slurry to a predetermined temperature. Although the preheater 51 will not be specifically limited if the slurry which passes the inside of the preheater 51 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 flow path of the slurry passing through the preheater 51, and the slurry passing through the preheater 51 can be heated by supplying a heating medium such as steam or oil to the heating pipe. .

  As a minimum of the temperature of the slurry after the heating by the preheater 51, 300 degreeC is preferable and 360 degreeC is more preferable. On the other hand, the upper limit of the temperature of the slurry is not particularly limited as long as it is a temperature at which elution is possible, but 420 ° C. is preferable, and 400 ° C. is more preferable. 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 other hand, 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 manufacturing cost.

  The slurry heated by the preheater 51 is supplied to the extraction tank 52. In the extraction tank 52, the coal component soluble in the solvent is eluted from the coal while maintaining the temperature of the slurry. The extraction tank 52 has a stirrer 52a. The elution can be promoted by stirring the slurry with the stirrer 52a.

  Although the heating time in the heating part 5 is not specifically limited, 10 minutes or more and 70 minutes or less are preferable from a viewpoint of the extraction amount and extraction efficiency of a solvent soluble component. Here, the “heating time in the heating unit 5” is the total heating time in the preheater 51 and the extraction tank 52.

  A part of the solvent contained in the slurry heated in the extraction tank 52 of the heating unit 5 is evaporated. The evaporated solvent is a vapor of about 300 ° C. or higher and 420 ° C. or lower, accumulates in the upper part of the extraction tank 52, and is supplied to the heat exchanging unit 9 through the first solvent recovery channel 101. Specifically, the first solvent recovery channel 101 is connected to the cooling medium supply channel 100, and the solvent is cooled and liquefied by a heat exchanger 101a disposed on the first solvent recovery channel 101. After that, it is supplied to the heat exchange unit 9 as a cooling medium.

  The temperature of the solvent recovered from the extraction tank 52 is about 100 ° C. or higher and 150 ° C. or lower after cooling. Further, the amount of the solvent recovered is about 0.5 kg or more and 0.7 kg or less per 1 kg of ashless coal to be produced.

<Solid-liquid separation unit>
The solid-liquid separation unit 6 separates, from the slurry, a solution in which the coal component obtained in the heating unit 5 is dissolved in a solvent and a solid concentrate containing a solvent-insoluble component. 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.

  Specifically, the separation in the solid-liquid separation unit 6 can be performed by a gravity sedimentation method. Here, the gravity sedimentation method is a separation method in which a solid content is settled using gravity to separate the solid and the liquid.

  The ashless coal manufacturing apparatus discharges a solution containing a solvent-soluble component from the top while continuously supplying slurry into the solid-liquid separation unit 6, and a solid content concentrate containing a solvent-insoluble component from the bottom. Can be discharged. Thereby, continuous solid-liquid separation processing becomes possible.

  The solution containing the solvent-soluble component accumulates at the top of the solid-liquid separation unit 6. This solution is filtered using a filter unit as necessary, and then discharged to the first solvent separation unit 7. On the other hand, the solid concentrate containing the solvent-insoluble component is collected at the lower part of the solid-liquid separation unit 6 and discharged to the second solvent separation unit 8.

  Although the time which maintains a slurry in the solid-liquid separation part 6 is not specifically limited, For example, it is 30 minutes or more and 120 minutes or less, and sedimentation separation in the solid-liquid separation part 6 is performed within this time. In addition, when lump coal is used as coal, since sedimentation separation is made efficient, the time which maintains a slurry in the solid-liquid separation part 6 can be shortened.

  The inside of the solid-liquid separation unit 6 is preferably heated and pressurized. As a minimum of heating temperature in solid-liquid separation part 6, 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 6, 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 6, 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 6.

  A part of the solvent contained in the slurry heated in the solid-liquid separation unit 6 is evaporated. The evaporated solvent is a vapor of about 300 ° C. or higher and 420 ° C. or lower, accumulates in the upper part of the solid-liquid separation unit 6, and is supplied to the heat exchange unit 9 through the second solvent recovery channel 102. Specifically, the second solvent recovery channel 102 is connected to the cooling medium supply channel 100, and the solvent is cooled and liquefied by a heat exchanger 102a disposed on the second solvent recovery channel 102. After that, it is supplied to the heat exchange unit 9 as a cooling medium.

  The temperature of the solvent recovered from the solid-liquid separation unit 6 is about 100 ° C. or higher and 150 ° C. or lower after cooling, and is a liquid at normal pressure. Further, the amount of the solvent recovered is about 0.5 kg or more and 0.7 kg or less per 1 kg of ashless coal to be produced.

<First solvent separation unit>
The first solvent separation unit 7 evaporates the solvent from the solution separated by the solid-liquid separation unit 6. Ashless coal (HPC) is obtained by evaporating and separating the solvent.

  The ashless coal thus obtained has an ash content of 5% by mass or less or 3% by mass or less, contains almost no ash, has no moisture, and exhibits a higher calorific value than, for example, raw 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 be used as a blended coal for coke raw materials.

  As a method for evaporating and separating the solvent, a separation method including a general distillation method or an evaporation method (spray drying method or the like) can be used. By separating the solvent from the solution, ashless coal substantially free of ash can be obtained from the solution.

  In addition, the ashless coal obtained in the 1st solvent separation part 7 is a liquid, The temperature is about 200 degreeC or more and 350 degrees C or less.

  Further, the solvent evaporated in the first solvent separation unit 7 is a vapor of about 250 ° C. or more and 350 ° C. or less, and is supplied to the heat exchange unit 9 via the third solvent recovery channel 103. Specifically, the third solvent recovery channel 103 is connected to the cooling medium supply channel 100, and the solvent is cooled and liquefied by a heat exchanger 103 a disposed on the third solvent recovery channel 103. After that, it is supplied to the heat exchange unit 9 as a cooling medium.

  The temperature of the solvent recovered from the first solvent separation unit 7 is about 180 ° C. or higher and 250 ° C. or lower after cooling. The amount of the solvent recovered is about 8 kg or more and 12 kg or less per 1 kg of ashless coal to be produced.

<Second solvent separation unit>
The second solvent separating unit 8 evaporates and separates the solvent from the solid concentrate separated by the solid-liquid separating unit 6 to obtain by-product coal (RC).

  By-product charcoal does not show softening and melting properties, but the oxygen-containing functional groups are eliminated. Therefore, by-product coal does not inhibit the softening and melting properties of other coals contained in this blended coal when used as a blended coal. Therefore, this blended coal can also be used as a part of the blended coal of the coke raw material. The coal blend may be discarded without being collected.

  As a method for separating the solvent from the solid concentrate, a general distillation method or an evaporation method (spray drying method or the like) can be used as in the separation method of the first solvent separation unit 7. By separation and recovery of the solvent, by-product charcoal in which solvent-insoluble components including ash and the like are concentrated from the solid concentrate can be obtained.

  Further, the solvent evaporated in the second solvent separation unit 8 is a vapor of about 250 ° C. or more and 350 ° C. or less, and is supplied to the heat exchange unit 9 through the fourth solvent recovery channel 104. Specifically, the fourth solvent recovery flow path 104 is connected to the cooling medium supply flow path 100, and the solvent is cooled and liquefied by a heat exchanger 104 a disposed on the fourth solvent recovery flow path 104. After that, it is supplied to the heat exchange unit 9 as a cooling medium.

  The temperature of the solvent recovered from the second solvent separation unit 8 is about 130 ° C. or higher and 180 ° C. or lower after cooling, and becomes liquid at normal pressure. The amount of the solvent recovered is about 1 kg or more and 1.5 kg or less per 1 kg of ashless coal produced.

<Heat exchange part>
The heat exchanging unit 9 cools the liquid ashless coal obtained in the first solvent separating unit 7 by exchanging heat with a cooling medium. By this heat exchange, solid ashless coal (HPC) is obtained. The heat exchange unit 9 includes a first heat exchanger 91 and a second heat exchanger 92 connected in series.

  As a heat exchanger used for the 1st heat exchanger 91 and the 2nd heat exchanger 92, publicly known heat exchangers, such as a cooling type steel belt conveyor and a double pipe type screw conveyor, can be used. For example, when using a double-pipe screw conveyor, heat exchange can be performed by supplying ashless coal, which is an object to be cooled, inside the screw conveyor (shell side) and supplying a cooling medium to the outer wall or shaft of the screw conveyor.

(First heat exchanger)
In the first heat exchanger 91, the ashless coal obtained in the first solvent separation unit 7 is cooled. Moreover, as a cooling medium of the 1st heat exchanger 91, since it uses as a solvent in the mixing part 3, if it melts | dissolves coal (coal solution), it will not specifically limit, The solvent mixed in the mixing part 3 Use the same type as.

  The upper limit of the temperature at the inlet of the heat exchange section 9 for the cooling medium is preferably 200 ° C, more preferably 150 ° C. If the temperature at the inlet of the cooling medium exceeds the above upper limit, the temperature difference with ashless coal becomes too small, so the heat exchange efficiency with ashless coal is reduced, and the production efficiency of ashless coal may be reduced. There is. On the other hand, the lower limit of the temperature at the inlet of the cooling medium is not particularly limited, and can be, for example, room temperature (25 ° C.). If the temperature at the inlet of the cooling medium is lower than the lower limit, it may be necessary to forcibly cool the cooling medium, which may increase the operating cost for cooling.

  The lower limit of the temperature at the outlet of the heat exchange section 9 for the cooling medium is preferably 40 ° C, more preferably 50 ° C. On the other hand, the upper limit of the temperature at the outlet of the cooling medium is preferably 250 ° C, more preferably 220 ° C. If the temperature at the outlet of the cooling medium is less than the lower limit, a large amount of the cooling medium is required, so that the ashless coal manufacturing apparatus cannot process the cooling medium, and the ashless coal has a sufficient amount of heat. May not be reusable. On the contrary, if the temperature at the outlet of the cooling medium exceeds the upper limit, the temperature difference from ashless coal becomes too small, the required heat transfer area of the heat exchanger becomes large, and the manufacturing cost of the heat exchanger is reduced. There is a risk that it may increase or the heat exchanger cannot be designed.

  The lower limit of the difference between the temperature at the outlet and the temperature at the inlet of the heat exchanger 9 of the cooling medium is preferably 15 ° C, more preferably 20 ° C. On the other hand, the upper limit of the temperature difference is preferably 90 ° C, more preferably 70 ° C. If the temperature difference is less than the lower limit, a large amount of the cooling medium is required. Therefore, the manufacture of the ashless coal cannot process the cooling medium, and the heat of the ashless coal may not be sufficiently reused. . Conversely, if the temperature difference exceeds the upper limit, the necessary heat transfer area of the heat exchanger increases, which may increase the manufacturing cost of the heat exchanger or make it impossible to design the heat exchanger.

  The temperature of the cooling medium at the inlet of the heat exchange unit 9 is set lower than the temperature of the ashless coal before cooling in the heat exchange unit 9. As a minimum of the temperature difference, 100 ° C is preferred and 150 ° C is more preferred. If the temperature difference is less than the lower limit, the heat quantity of the ashless coal may not be sufficiently recovered in the cooling medium, and the reuse of the heat quantity of the ashless coal may be insufficient. In addition, since the temperature of the ashless coal before cooling is about 300 ° C. or higher and about 350 ° C. or lower, if the temperature difference is less than the lower limit, the temperature of the solvent exceeds the boiling point and recycling of the heat of the ashless coal is not possible. May be sufficient. On the other hand, the upper limit of the temperature difference is not particularly limited, but is usually 300 ° C. or lower.

  The temperature of the cooling medium at the outlet of the heat exchange unit 9 is lower than the temperature of the ashless coal after cooling in the first heat exchanger 91. As a minimum of the temperature difference, 3 ° C is preferred and 5 ° C is more preferred. On the other hand, the upper limit of the temperature difference is preferably 80 ° C, more preferably 40 ° C, and even more preferably 10 ° C. If the temperature difference is less than the lower limit, the required heat transfer area of the heat exchanger increases, which may increase the manufacturing cost of the heat exchanger or make it impossible to design the heat exchanger. On the contrary, if the temperature difference exceeds the upper limit, the heat quantity of the ashless coal is not sufficiently recovered in the cooling medium, so that the reuse of the heat quantity of the ashless coal may be insufficient.

  As a minimum of the supply amount of the cooling medium per 1 kg of ashless coal, 0.4 kg is preferred and 0.5 kg is more preferred. On the other hand, the upper limit of the supply amount is preferably 15 kg, more preferably 12 kg, and even more preferably 5 kg. When the supply amount is less than the lower limit, the heat quantity of the ashless coal is not sufficiently recovered in the cooling medium, and the reuse of the heat quantity of the ashless coal may be insufficient. On the contrary, when the supply amount exceeds the upper limit, the temperature of the cooling medium after heat exchange is not sufficiently increased, and the reuse of the heat amount of ashless coal may be insufficient.

  The cooling medium used as the cooling medium in the heat exchange unit 9 is supplied to the solvent supply unit 2 via the cooling medium delivery channel 110. By supplying the cooling medium to the solvent supply unit 2, the cooling medium used in the cooling medium is supplied from the solvent supply unit 2 to the mixing unit 3 and used as a part or all of the solvent.

  The cooling medium is supplied via the cooling medium supply channel 100. Connected to the cooling medium supply channel 100 are a first solvent recovery channel 101, a second solvent recovery channel 102, a third solvent recovery channel 103, and a fourth solvent recovery channel 104. The prepared solvent is configured to be supplied to the heat exchange unit 9. Further, a new cooling medium can be supplied from the upstream side of the cooling medium supply channel 100 as necessary.

  As a minimum of the temperature of the ashless coal after cooling in the 1st heat exchanger 91, 50 ° C is preferred and 60 ° C is more preferred. On the other hand, the upper limit of the temperature of the ashless coal after cooling is preferably 280 ° C, more preferably 260 ° C. When the temperature of the ashless coal after cooling is less than the lower limit, the temperature difference between the ashless coal before and after cooling becomes large. Since it is necessary to lengthen the heat exchange time or increase the amount of the cooling medium to be supplied in accordance with the temperature difference before and after the cooling, if the temperature difference becomes too large, the production efficiency of ashless coal decreases. There is a fear. On the other hand, if the temperature of the ashless coal after cooling exceeds the above upper limit, the amount of heat of the ashless coal becomes difficult to be collected in the cooling medium and may not be sufficiently reused.

  As a minimum of a temperature difference of ashless coal before and behind cooling in the 1st heat exchanger 91, 30 ° C is preferred and 40 ° C is more preferred. Moreover, as an upper limit of the temperature difference of the said ashless coal, 250 degreeC is preferable and 240 degreeC is more preferable. If the temperature difference of the ashless coal is less than the above lower limit, the heat quantity of the ashless coal is not sufficiently recovered in the cooling medium, and there is a possibility that the reuse of the heat quantity of the ashless coal becomes insufficient. In addition, since ashless coal having a relatively high temperature is supplied to the second heat exchanger 92, which will be described later, the amount of cooling water used as a cooling medium increases, and the effect of reducing the amount of cooling water used may be insufficient. is there. On the other hand, the temperature difference of the ashless coal exceeds the upper limit because it is necessary to lengthen the heat exchange time or increase the amount of the cooling medium to be supplied according to the temperature difference of the ashless coal before and after cooling. And there exists a possibility that the manufacture efficiency of ashless coal may fall.

(Second heat exchanger)
In the second heat exchanger 92, the ashless coal cooled in the first heat exchanger 91 is further cooled. Moreover, in the 2nd heat exchanger 92, what is not utilized as a solvent by the mixing part 3 as a cooling medium, for example, water (cooling water), is used.

  As an upper limit of the temperature in the inflow port of the heat exchanger 9 of the cooling water, 50 ° C. is preferable, 40 ° C. is more preferable, and 30 ° C. is more preferable. If the temperature at the cooling water inlet exceeds the above upper limit, heat exchange cannot be efficiently performed with ashless coal, and the production efficiency of ashless coal may be reduced. On the other hand, the lower limit of the temperature at the cooling water inflow port is not particularly limited, and may be, for example, room temperature (25 ° C.). If the temperature at the cooling water inlet is less than the lower limit, it may be necessary to forcibly lower the temperature of the cooling water, which may increase the operating cost for lowering the temperature of the cooling water.

  The lower limit of the temperature at the outlet of the heat exchanger 9 of the cooling water is preferably 30 ° C, more preferably 40 ° C. On the other hand, the upper limit of the temperature at the cooling water outlet is preferably 60 ° C, more preferably 50 ° C. If the temperature at the outlet of the cooling water is less than the lower limit, a large amount of cooling water is required to cool the ashless coal to a desired temperature. is there. On the other hand, when the temperature at the outlet of the cooling water exceeds the upper limit, the operating cost for lowering the temperature of the cooling water increases, making it difficult to reuse the cooling water. For this reason, new cooling water is required, and the effect of reducing the amount of cooling water used may be insufficient.

  The lower limit of the difference between the temperature at the outlet of the heat exchanger 9 and the temperature at the inlet is preferably 5 ° C, more preferably 7 ° C. On the other hand, the upper limit of the temperature difference is preferably 15 ° C and more preferably 13 ° C. If the temperature difference is less than the lower limit, a large amount of cooling water is required to cool the ashless coal to a desired temperature, and therefore the effect of reducing the amount of cooling water used may be insufficient. Conversely, if the temperature difference exceeds the upper limit, the operating cost for reducing the temperature of the cooling water may become too high.

  The temperature at the inlet of the heat exchanger 9 of the cooling water is set to be equal to or lower than the temperature of the ashless coal before cooling in the second heat exchanger 92. As an upper limit of the temperature difference, 200 ° C. is preferable, and 190 ° C. is more preferable. If the above temperature difference exceeds the above upper limit, a large amount of cooling water is required to cool the ashless coal to a desired temperature, and therefore the effect of reducing the amount of cooling water used may be insufficient. On the other hand, the lower limit of the temperature difference is not particularly limited as long as it is cooled to a temperature at which ashless coal can be handled safely, and may be 0 ° C. That is, for example, when the ashless coal is sufficiently cooled by the first heat exchanger 91, the second heat exchanger 92 may not be cooled.

  The temperature at the outlet of the heat exchanger 9 of the cooling water is equal to or lower than the temperature of the ashless coal after cooling in the second heat exchanger 92. As a minimum of the temperature difference, 10 ° C is preferred and 20 ° C is more preferred. If the temperature difference is less than the lower limit, the time required for heat exchange becomes too long, and the production efficiency of ashless coal may be reduced. On the other hand, the upper limit of the temperature difference is not particularly limited as long as the ashless coal is cooled to a temperature at which it can be handled safely.

  As an upper limit of the amount of cooling water supplied per kg of ashless coal, 7 kg is preferable, and 6.5 kg is more preferable. If the supply amount exceeds the upper limit, the cooling water usage reduction effect may be insufficient. On the other hand, the lower limit of the supply amount is not particularly limited as long as the ashless coal is cooled to a temperature at which it can be safely handled, and 0 kg, that is, the second heat exchanger 92 may not be used for cooling.

  As a minimum of the temperature of the ashless coal after cooling in heat exchange part 9, 40 ° C is preferred and 50 ° C is more preferred. On the other hand, as an upper limit of the temperature of the ashless coal after cooling, 100 ° C is preferable, and 80 ° C is more preferable. When the temperature of the ashless coal after cooling is less than the lower limit, the temperature difference between the ashless coal before and after cooling becomes large. Since it is necessary to lengthen the time for heat exchange or increase the amount of cooling water to be supplied according to the temperature difference before and after cooling, if the temperature difference becomes too large, the production efficiency of ashless coal decreases. There is a fear. Conversely, if the temperature of the ashless coal after cooling exceeds the above upper limit, the solid ashless coal after cooling may not be handled safely.

  As an upper limit of the temperature difference of the ashless coal before and behind cooling in the heat exchange part 9, 300 degreeC is preferable and 250 degreeC is more preferable. If the above temperature difference exceeds the above upper limit, a large amount of cooling water is required to cool the ashless coal to a desired temperature, and therefore the effect of reducing the amount of cooling water used may be insufficient. On the other hand, the lower limit of the temperature difference is not particularly limited as long as it is cooled to a temperature at which ashless coal can be handled safely, but is usually about 150 ° C.

  As a minimum of time when ashless coal is cooled by heat exchanging part 9, 5 minutes are preferred and 10 minutes are more preferred. On the other hand, the upper limit of the cooling time is preferably 30 minutes, and more preferably 20 minutes. If the cooling time is less than the lower limit, it is necessary to rapidly cool the ashless coal to a desired temperature, so a large amount of cooling medium is required, and the production cost of the ashless coal may increase. Conversely, if the cooling time exceeds the upper limit, the cooling time becomes unnecessarily long, and the production efficiency of ashless coal may be reduced.

  The lower limit of the ratio of the time during which the ashless coal is cooled in the first heat exchanger 91 to the time during which the ashless coal is cooled in the heat exchange unit 9 is preferably 10%, and more preferably 13%. If the ratio of the cooling times is less than the lower limit, the amount of heat recovered by the solvent is reduced, so that the reuse of the amount of heat of ashless coal may be insufficient. On the other hand, the upper limit of the cooling time ratio is not particularly limited as long as ashless coal can be cooled to a desired temperature, and may be 100%. For example, if the ratio of the cooling time is the heat exchanging portion 9 in FIG. 1, the length of the portion (first cooling zone) where the ashless coal is cooled by the first heat exchanger 91 and the second heat exchange. It can be controlled by the ratio with the length of the portion (second cooling zone) where the ashless coal is cooled in the vessel 92. Specifically, the flow rate of the ashless coal passing through the heat exchange unit 9 is constant, and the ratio of the length of the first cooling zone to the sum of the lengths of the first cooling zone and the second cooling zone is the cooling time. The ratio may be within the range.

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

<Mixing process>
In the mixing step, coal and solvent are mixed. Specifically, the coal supplied from the coal supply unit 1 and the solvent supplied from the solvent supply unit 2 are mixed in the preparation tank 31 of the mixing unit 3 to form a slurry.

<Heating process>
In the heating step, the slurry obtained in the mixing step is heated. Specifically, the following procedure is performed. First, the slurry prepared in the mixing step is supplied to the preheater 51 of the heating unit 5 by the pump 4 and heated to a predetermined temperature. Thereafter, the slurry is supplied to the extraction tank 52, and extraction is performed while being held at a predetermined temperature while being stirred by the stirrer 52a.

<Separation process>
In the separation step, a solution in which the coal component obtained in the heating step is dissolved in a solvent and a solid concentration liquid containing a solvent-insoluble component are separated from the slurry. Specifically, the slurry discharged from the extraction tank 52 is supplied, and the slurry supplied by, for example, the gravity sedimentation method in the solid-liquid separation unit 6 is separated into the solution and the solid content concentrate.

<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 6 is supplied to the first solvent separation unit 7, and the solvent is evaporated by the first solvent separation unit 7. This separates the solution into solvent and ashless coal. The ashless coal obtained in the first evaporation step is liquid.

<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 concentration liquid separated by the solid-liquid separation unit 6 is supplied to the second solvent separation unit 8, and the solvent is evaporated by the second solvent separation unit 8 to separate the solvent into by-product coal. .

<Recovery process>
In the recovery process, the solvent is recovered in the heating process, the separation process, the first evaporation process, and the second evaporation process. Specifically, the solvent is recovered in each step as follows. In the recovery in the heating step, the solvent that is evaporated by the heating of the heating unit 5 is recovered through the first solvent recovery channel 101. In the recovery in the separation step, the solvent evaporated by heating in the solid-liquid separation unit 6 is recovered through the second solvent recovery flow channel 102. In the recovery in the first evaporation step, the solvent evaporated and separated by the first solvent separation unit 7 is recovered via the third solvent recovery flow path 103. In the recovery in the second evaporation step, the solvent evaporated and separated by the second solvent separation unit 8 is recovered through the fourth solvent recovery flow path 104. These recovered solvents are used as a cooling medium in the heat exchange step described later.

  In the method for producing ashless coal, the amount of solvent newly supplied as the cooling medium can be reduced by using the solvent recovered in each step as the cooling medium in the heat exchange step. Moreover, since the temperature of the solvent recovered in the heating step and the separation step is relatively low, a decrease in the efficiency of heat exchange in the heat exchange step can be suppressed by using this solvent alone or in combination. In addition, since the amount of the solvent recovered in the first evaporation step and the second evaporation step is relatively large, the amount of the newly supplied solvent can be particularly reduced. Furthermore, the temperature of the solvent rises due to heating in each step. By supplying the solvent having this heat amount to the mixing unit 3 through the heat exchange unit 9, in addition to the heat amount of ashless coal, Part of the amount of heat consumed can be reused.

<Heat exchange process>
In the heat exchange step, the liquid ashless coal obtained in the first evaporation step is heat exchanged with the cooling medium. Specifically, the ashless coal obtained in the first evaporation step is cooled by the first heat exchanger 91 of the heat exchange unit 9 using a cooling medium that is used as a solvent in the mixing step, and then not used in the mixing step. Further cooling is performed by the second heat exchanger 92 using the cooling medium.

  As a result of this heat exchange, the ashless coal that has been liquid in the cooling process begins to solidify at a temperature of 150 ° C. or higher and 200 ° C. or lower, and is finally cooled to 100 ° C. or lower and becomes solid. Thereby, solid ashless coal is obtained. The obtained solid ashless coal is extruded and collected by a screw conveyor, for example, when using a double tube screw conveyor as a heat exchanger.

  Note that the cooling medium used in the first heat exchanger 91 is supplied to the solvent supply unit 2 via the cooling medium delivery channel 110. By supplying the cooling medium to the solvent supply unit 2, the cooling medium is supplied to the mixing unit 3 and used as part or all of the solvent.

〔advantage〕
Since the ashless coal manufacturing apparatus includes the cooling medium delivery channel 110 that supplies the cooling medium after the heat exchange of the heat exchange unit 9 to the mixing unit 3, the cooling medium for cooling the ashless coal is used as the mixing unit. 3 can be used as a solvent. For this reason, the usage-amount of cooling water can be reduced by using the said ashless coal manufacturing apparatus, without introduce | transducing a cooling medium newly. Moreover, since the said ashless coal manufacturing apparatus can use the solvent which collect | recovered the calorie | heat amount of ashless coal as a solvent mixed in the mixing part 3, the calorie | heat amount of ashless coal can be reused for heating of a slurry. . Therefore, the manufacturing cost of ashless coal can be reduced by using the said ashless coal manufacturing apparatus.

  Moreover, since the manufacturing method of the said ashless coal cools ashless coal with the solvent used at a mixing process, it can reduce the usage-amount of cooling water, without introduce | transducing a cooling medium newly. Moreover, the manufacturing method of the said ashless coal raises the temperature of the slurry obtained by a mixing process by reusing the calorie | heat amount of ashless coal. This can reduce the amount of heat required for heating in the heating step. Therefore, the production cost of ashless coal can be reduced by using the method for producing ashless coal.

[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 case where the ashless coal manufacturing apparatus includes the first solvent recovery channel, the second solvent recovery channel, the third solvent recovery channel, and the fourth solvent recovery channel is described. The solvent recovery channel may not include a part or all of the solvent recovery channel.

  Moreover, although the said embodiment demonstrated the case where all the solvent collect | recovered by a heating process, a separation process, a 1st evaporation process, and a 2nd evaporation process was used as a cooling medium of a heat exchange process as a manufacturing method of ashless coal. It is not necessary to recover part or all of the solvent. For example, you may use only the solvent collect | recovered in a specific process.

  In the above embodiment, the heat exchanging unit has the first heat exchanger and the second heat exchanger, the first heat exchanger uses the solvent used in the mixing unit as a cooling medium, and the second heat exchanger cools. Although the case where the cooling water not used in the mixing unit is used as the medium has been described, a cooling medium used in the mixing unit may be used for both the first heat exchanger and the second heat exchanger. For example, the solvent recovered by the third solvent recovery channel and the fourth solvent recovery channel having a relatively high temperature are used as the cooling medium of the first heat exchanger, and the temperature of the second heat exchanger is relatively low. By using the low first solvent recovery channel and the second solvent recovery channel, solid ashless coal (HPC) can be obtained. Moreover, when using both the cooling medium of a 1st heat exchanger and a 2nd heat exchanger as a solvent, the solvent used for cooling can be used as a solvent in the said mixing process.

  Further, the number of heat exchangers included in the heat exchange unit is not limited to 2, and may be 1 or 3 or more.

  Moreover, in the said embodiment, although the case where a 2nd evaporation process was provided as a manufacturing method of ashless coal was demonstrated, for example, when not using a byproduct 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 heat exchanger and a 4th solvent collection | recovery flow path.

  Moreover, in the said embodiment, although the preparation part of the manufacture apparatus of ashless coal demonstrated the structure which has a preparation tank, if not only this structure but mixing of a solvent and coal can be performed, a preparation tank may be abbreviate | omitted. . 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 solid-liquid separation unit.

  In the above-described embodiment, the method of performing the separation step by continuous processing has been described. However, the separation step may not be performed by continuous processing, and for example, batch processing may be performed in which slurry is stored and separated in a solid-liquid separation unit. .

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Comparative Example 1]
The amount of cooling water required for cooling the ashless coal from 300 ° C. to 70 ° C. using only 35 ° C. cooling water was calculated by simulation. In the calculation, the production amount of ashless coal was set to 10,000 kg / h. The difference between the temperature at the outlet of the cooling water heat exchanger and the temperature at the inlet was 10 ° C.

  The required amount of cooling water obtained by simulation was 82,800 kg / h. Since the temperature difference between the cooling water inlet and outlet is 10 ° C., the amount of heat required to cool the ashless coal from 300 ° C. to 70 ° C. is 828,000 kcal / h.

  Moreover, the temperature change of the ashless coal calculated from the said simulation result and cooling water is shown in FIG. In FIG. 2, the horizontal axis of the graph represents the position of the heat exchange section in the cooling zone (distance from the inlet of the heat exchange section), the left end means the inlet of the heat exchange section, and the right end of the graph shows the outlet of the heat exchange section. means.

[Example 1]
The amount of solvent and the amount of solvent required for cooling by using only the solvent (1-methylnaphthalene) used for extraction of ashless coal from 300 ° C to 70 ° C and extracting ashless coal in the heat exchange section by simulation The temperature rise was calculated. In the calculation, the production amount of ashless coal was set to 10,000 kg / h. The amount of heat necessary for cooling the ashless coal was 828,000 kcal / h, which was the same as in Comparative Example 1, and the temperature of the solvent supplied was 35 ° C. The length of the cooling zone (distance between the inlet and outlet of the heat exchange unit) was the same as in Comparative Example 1.

  As a result of the simulation, the amount of the required solvent was 100,000 kg / h, and the solvent was heated to 60 ° C. Moreover, the temperature change of ashless coal and a solvent computed from the simulation result is shown in FIG.

[Example 2]
According to the simulation, when the ashless coal at 300 ° C. is cooled using the solvent recovered in the heating process and further cooled to 70 ° C. using the cooling water, the ashless coal is cooled by the solvent in the entire cooling zone. The ratio of the length of the zone for cooling (first cooling zone), the temperature rise of the solvent, and the amount of cooling water required were calculated so that the temperature rise of the solvent was maximized. The temperature of the solvent recovered in the heating step was 120 ° C., and the amount of the solvent was 6,000 kg / h. The entire length of the cooling zone is the same as in Comparative Example 1, and the temperature at the cooling water inlet in the zone (second cooling zone) in which ashless coal is cooled with cooling water is 35 ° C. The difference between the temperature at the outlet and the temperature at the inlet was 10 ° C.

  As a result of the simulation, the first cooling zone was 25% of the entire cooling zone, and the remaining 75% became the second cooling zone. Moreover, the temperature of the ashless coal at the time of passing through the 1st cooling zone was 250 degreeC, and the solvent was heated to 180 degreeC. The amount of cooling water required in the second cooling zone was 64,800 kg / h. Moreover, the temperature change of ashless coal, a solvent, and cooling water computed from the said simulation result is shown in FIG.

[Example 3]
In the simulation, when the solvent recovered in the heating step and the second evaporation step is mixed and used, the ashless coal at 300 ° C. is cooled and the ashless coal is cooled to 70 ° C. using cooling water. The ratio of the length of the first cooling zone in the entire zone, the temperature rise of the solvent, and the amount of cooling water required were calculated so as to maximize the temperature rise of the solvent. The temperature of the solvent recovered in the heating step was 120 ° C., the amount of the solvent was 6,000 kg / h, the temperature of the solvent recovered in the second evaporation step was 150 ° C., and the amount of the solvent was 11,000 kg / h. . By mixing these solvents, a solvent of 17,000 kg / h is obtained at 140 ° C. as a solvent for the cooling medium. Further, the entire length of the cooling zone is the same as in Comparative Example 1, and the temperature at the inlet of the cooling water heat exchanger in the second cooling zone is 35 ° C., and at the outlet of the cooling water heat exchanger. The difference between the temperature and the temperature at the inlet was 10 ° C.

  As a result of the simulation, the first cooling zone was 15% of the entire cooling zone, and the remaining 85% became the second cooling zone. Moreover, the temperature of the ashless coal at the time of passing through the 1st cooling zone was 210 degreeC, and the solvent was heated to 200 degreeC. The amount of cooling water required in the second cooling zone was 50,400 kg / h. Moreover, the temperature change of ashless coal, a solvent, and cooling water computed from the said simulation result is shown in FIG.

[Evaluation]
Based on the simulation results, the amount of recovered heat of the solvent and the reduction rate of the cooling water were evaluated.

<Recovered heat amount>
The amount of heat recovered from the solvent includes the amount of heat recovered from 300 ° C. ashless coal in the heat exchange step and the amount of heat recovered from each step by using the solvent heated in the heating step or the second evaporation step. These were evaluated separately.

(Recovery effect from heat exchange process)
The total amount of heat that needs to be recovered in order to cool the ashless coal from 300 ° C. to 70 ° C. in the heat exchange step is 828,000 kcal / h. In Comparative Example 1, all of this total heat is recovered by 82,800 kg / h of cooling water. In each embodiment, since the temperature change of the cooling water is the same at 10 ° C., the amount of heat recovered by the cooling water is proportional to the amount of the cooling water. From this, in Examples 1 to 3, the amount of heat recovered by the cooling water in each Example is calculated using the ratio of the amount of cooling water to Comparative Example 1, and the amount of heat is calculated as 828,000 kcal / The amount of heat subtracted from h was taken as the solvent recovery heat amount. The amount of heat required in the heating step is reduced by the amount of heat recovered by the solvent. The reduction ratio due to the recovered heat amount was calculated based on the necessary heat amount in the heating process when heat recovery was not performed. The results are shown in Table 1.

(Recovery effect from heating process and second evaporation process)
In Example 2, the solvent recovered in the heating process is used. In Example 3, the solvent recovered in the heating step and the second evaporation step is used. Since these solvents are heated in each step, the temperature is high. In Example 2 and Example 3, the amount of heat required in the heating step is reduced also by the amount of heat of the solvent whose temperature has increased. The amount of heat recovered by the solvent heated in the heating step and the second evaporation step, and the reduction ratio due to the recovered heat amount with respect to the required amount of heat in the heating step when heat recovery is not performed were calculated. The results are shown in Table 1. In Example 1 and Comparative Example 1, since the heat amount of the heating step and the second evaporation step is not recovered, both the recovered heat amount and the reduction rate are 0.

(Total collection effect)
The sum of the reduction ratio due to the amount of heat recovered from the heat exchange step and the reduction ratio due to the amount of heat recovered from the heating step and the second evaporation step was calculated as the total recovery effect. The results are shown in Table 1.

<Reduction ratio of cooling water>
The reduction ratio of the cooling water was calculated based on the ratio of the cooling water flow rate reduced with respect to the cooling water flow rate of Comparative Example 1 with Comparative Example 1 as a reference. The results are shown in Table 1.

  From the results of Table 1, according to the simulation results of Examples 1 to 3, the amount of cooling water required for cooling the ashless coal can be reduced compared to the simulation results of Comparative Example 1, and the calorific value of the ashless coal is the solvent. Can be recovered. On the other hand, in Comparative Example 1, since no solvent is used as the cooling medium, the amount of cooling water used cannot be reduced, and the heat of ashless coal cannot be recovered and reused. From the above, it can be seen that by using a solvent as the cooling medium, it is possible to reduce the cooling water necessary for cooling the ashless coal and to reuse the heat quantity of the ashless coal.

  Moreover, from the results of Example 2 and Example 3, in addition to the calorific value of ashless coal by using a solvent having a calorific value by heating in the heating step and the second evaporation step in the heating step, It can be seen that a part of the heat consumed by heating in the process can be reused, and the heat recovery effect can be further enhanced. In particular, in Example 3, since the amount of the solvent recovered in the second evaporation step is relatively large, the amount of newly supplied solvent can be particularly reduced, and a total recovery effect equivalent to that in Example 1 can be obtained. I understand.

  As described above, the method and apparatus for producing ashless coal according to the present invention can reduce the cooling water necessary for cooling the ashless coal and reuse the heat quantity of the ashless coal. Therefore, by using the method and apparatus for producing ashless coal of the present invention, the production cost of ashless coal associated with the use of cooling water and the heat of heating of the slurry can be reduced.

DESCRIPTION OF SYMBOLS 1 Coal supply part 2 Solvent supply part 3 Mixing part 31 Preparation tank 31a Stirrer 4 Pump 5 Heating part 51 Preheater 52 Extraction tank 52a Stirrer 6 Solid-liquid separation part 7 1st solvent separation part 8 2nd solvent separation part 9 Heat Exchanger 91 First heat exchanger 92 Second heat exchanger 100 Cooling medium supply channel 101 First solvent recovery channel 102 Second solvent recovery channel 103 Third solvent recovery channel 104 Fourth solvent recovery channel 101a, 102a, 103a, 104a Heat exchanger 110 Cooling medium delivery flow path

Claims (3)

Mixing coal and solvent;
Heating the slurry obtained in the mixing step,
Separating the solution in which the coal component obtained in the heating step is dissolved in a solvent from the slurry;
Evaporating the solvent from the solution separated in the separation step;
A step of heat-exchanging the liquid ashless coal obtained in the evaporation step with a cooling medium,
The manufacturing method of ashless coal which uses the cooling medium in the said heat exchange process as a solvent in the said mixing process. A step of recovering the solvent in the heating step, the separation step, or the evaporation step;
The method for producing ashless coal according to claim 1, wherein the solvent recovered in the recovery step is used as a cooling medium in the heat exchange step. A mixing section for mixing coal and solvent;
A heating unit for heating the slurry obtained in the mixing unit;
A solid-liquid separation unit for separating the solution obtained by dissolving the coal component obtained in the heating unit in a solvent from the slurry;
A solvent separation unit for evaporating the solvent from the solution separated by the solid-liquid separation unit;
A heat exchanging unit that exchanges heat between the liquid ashless coal obtained in the solvent separation unit and a cooling medium;
An apparatus for producing ashless coal, comprising: a cooling medium delivery flow path for supplying the cooling medium after heat exchange in the heat exchange section to the mixing section.

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