JP6297412B2 - Ashless coal manufacturing apparatus and ashless coal manufacturing method - Google Patents

Description

  The present invention relates to an ashless coal manufacturing apparatus and an ashless coal manufacturing method.

  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 has been proposed in which a solution containing a coal component soluble in a solvent (hereinafter referred to as a solvent-soluble component) is separated from a slurry by using a gravity sedimentation method (for example, Japanese Patent Application Laid-Open No. 2009-2009). No. 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. 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 the extraction step of the conventional ashless coal manufacturing method, the slurry obtained in the slurry preparation step is heated to a predetermined temperature and supplied to the extraction tank. And the slurry supplied to the extraction tank is hold | maintained at predetermined temperature, stirring with a stirrer, and extraction of a solvent soluble component is performed. In the extraction step, the slurry is retained in the extraction tank for about 10 to 60 minutes in order to sufficiently dissolve the solvent-soluble component in the solvent. In addition, "extraction rate" means the ratio of the mass of the soluble component extracted to a solvent with respect to the anhydrous non-distribution mass of the coal used as a raw material.

  In the conventional method for producing ashless coal, the extraction of the solvent-soluble component in the extraction step is mainly performed in an extraction tank, so that a large extraction tank is required. Furthermore, when it takes a long time to extract the solvent-soluble component, a larger extraction tank must be installed, which increases equipment costs. Moreover, since the time required for extraction of the solvent-soluble component greatly affects the production time of ashless coal, shortening of the extraction time is conventionally required.

JP 2009-227718 A

  The present invention has been made based on the above circumstances, and provides an ashless coal production apparatus and an ashless coal production method capable of reducing the extraction time of solvent-soluble components and miniaturizing the extraction equipment. The purpose is to provide.

  The invention made in order to solve the above-mentioned problems includes a solvent supply part for supplying a heated solvent, a coal supply part for supplying coal, and the solvent and coal supplied from the solvent supply part and the coal supply part. An ashless coal by evaporative separation of the solvent from the solution separated by the solid-liquid separation unit, a solid-liquid separation unit for separating the solution in which the coal component is dissolved from the slurry in which the solvent and coal are mixed, An ashless charcoal manufacturing apparatus in which the mixing unit has a line mixer.

  In the ashless coal manufacturing apparatus, the mixing unit to which the coal is supplied from the coal supply unit and the solvent heated from the solvent supply unit is supplied has a line mixer. As a result, the temperature of the coal supplied to the mixing section is rapidly increased by mixing with the heated solvent, so the proportion of solvent-soluble components extracted in the line mixer increases and the extraction rate improves. To do. Moreover, since the said ashless coal manufacturing apparatus can extract the said solvent soluble component, conveying the slurry in which the said solvent and coal were mixed with the line mixer, it can shorten the processing time of the whole ashless coal manufacturing process. Moreover, since the said ashless coal manufacturing apparatus extracts the said solvent soluble component with a line mixer, the omission tank used for extraction can be abbreviate | omitted or reduced in size.

  The discharge port of the line mixer may be directly connected to the solid-liquid separator. Thus, by connecting the discharge port of the line mixer directly to the solid-liquid separator, an extraction tank for storing the slurry becomes unnecessary, and the extraction time of the solvent-soluble component can be further shortened.

  An extraction tank for storing the slurry discharged from the line mixer may be further provided. Thus, by providing the extraction tank which stores the slurry discharged | emitted from a line mixer, the said solvent soluble component can be extracted more reliably, and an extraction rate improves more.

  The temperature of the solvent supplied from the solvent supply unit is preferably 330 ° C. or higher and 450 ° C. or lower. Thus, by setting the temperature of the solvent supplied from the solvent supply unit within the above range, the slurry in which the solvent and coal are mixed more reliably rises to the extraction temperature (temperature within the temperature range where the extraction rate increases). The extraction rate of the solvent-soluble component in the mixing section is further improved.

  The solvent supply unit may include a pump that supplies the solvent to the mixing unit in a turbulent state. In this way, the solvent supply unit has a pump that supplies the solvent to the mixing unit in a turbulent state, so that mixing of the solvent and coal in the mixing unit is promoted, and more solvent-soluble components are dissolved in the solvent. Can be made.

  As coal supplied from the said coal supply part, what contains 80 mass% or more of inferior quality coal whose carbon content rate is 70 to 85 mass% is preferable. Thus, the production cost of ashless coal can be further reduced by using coal whose mass ratio of inferior coal to the whole coal is equal to or higher than the lower limit as coal supplied from the coal supply unit.

  Another invention made in order to solve the above problems is a method for producing ashless coal from slurry obtained by mixing coal and a solvent, and heating and supplying the solvent And the step of supplying coal, the step of mixing the solvent and coal with a line mixer, the step of separating the solution in which the coal component is dissolved from the slurry in which the solvent and coal are mixed, and the separation step. And a step of obtaining ashless coal by evaporative separation of the solvent from the solution.

  The method for producing ashless coal includes a step of mixing the coal supplied from the solvent supply step and the coal supply step and the heated solvent with a line mixer. As a result, since the coal supplied in the mixing step is rapidly heated by being mixed with the heated solvent, the proportion of solvent-soluble components extracted in the line mixer is increased, and the extraction rate is increased. improves. Moreover, since the said solvent-soluble component can be extracted, conveying the said slurry and the slurry with which coal was mixed with the line mixer, the manufacturing method of the said ashless coal can shorten the processing time of the whole ashless coal manufacturing process. Moreover, since the said ashless coal manufacturing method extracts the said solvent soluble component with a line mixer, the omission tank used for extraction can be abbreviate | omitted or reduced in size.

  Here, the “line mixer” means a device that continuously mixes two or more kinds of solutions and solids passing through the pipe. For example, a baffle plate installed in the pipe through which the solution and solids pass It is a concept that includes a device that mixes the solution or solid with a projection or a projection, or a device that mixes a solution or solid that passes through a mechanical stirring means in the pipe. The “carbon content” means the organic content (mass%) obtained by removing moisture and ash from coal, and can be measured according to JIS-M8819 (1997).

  As described above, according to the ashless coal production apparatus and the ashless coal production method of the present invention, the extraction time for the solvent-soluble component can be shortened and the extraction equipment can be downsized.

It is the schematic which shows the ashless coal manufacturing apparatus which concerns on 1st embodiment of this invention. It is the schematic which shows the ashless coal manufacturing apparatus which concerns on 2nd embodiment of this invention.

  Hereinafter, an embodiment of an ashless coal manufacturing apparatus and an ashless coal manufacturing method according to the present invention will be described in detail.

[First embodiment]
The ashless coal production apparatus 1 of FIG. 1 includes a solvent supply unit 2 that supplies heated solvent, a coal supply unit 3 that supplies coal, the solvent supplied from the solvent supply unit 2 and the coal supply unit 3, and The mixing unit 4 for mixing coal, the solid-liquid separation unit 5 for separating the solution in which the coal component is dissolved from the slurry in which the solvent and coal are mixed, and the solvent from the solution separated by the solid-liquid separation unit 5 And a first solvent separation unit 6 for obtaining ashless coal (HPC) by evaporative separation. The mixing unit 4 has a line mixer 8. Moreover, the ashless coal production apparatus 1 obtains by-product coal (RC) from a solid concentrate containing a coal component (hereinafter referred to as a solvent-insoluble component) separated by the solid-liquid separation unit 5 and insoluble in a solvent. A second solvent separation unit 7 is provided.

<Solvent supply unit>
The solvent supply unit 2 supplies the heated solvent to the mixing unit 4. As shown in FIG. 1, the solvent supply unit 2 mainly includes a solvent tank 10, a pump 11, and a preheater 12.

(Solvent tank)
The solvent tank 10 stores a solvent to be mixed with coal supplied from the coal supply 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, when the solvent is recovered in the ashless coal acquisition step of evaporating the solvent to obtain ashless coal, loss due to volatilization may increase and the solvent recovery rate may decrease. is there. On the other hand, when the boiling point of the solvent exceeds the upper limit, it is difficult to separate the solvent-soluble component from the solvent, and in this case, the solvent recovery rate may be lowered.

(pump)
The pump 11 is disposed in a pipe connected to the mixing unit 4. The pump 11 pumps the solvent stored in the solvent tank 10 to the mixing unit 4 through the supply pipe 9.

  The type of the pump 11 is not particularly limited as long as the solvent can be pumped to the mixing unit 4 through the supply pipe 9. For example, a positive displacement pump or a non-positive displacement pump can be used. More specifically, a diaphragm pump or a tube diaphragm pump 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 average flow rate of the solvent flowing through the supply pipe 9 by the pump 11 is preferably 0.5 m / s, and more preferably 1 m / s. On the other hand, the upper limit of the average flow rate of the solvent is preferably 4 m / s, and more preferably 3 m / s. If the average flow rate of the solvent is less than the lower limit, the stirring force in the line mixer 8 of the slurry in which the solvent and coal are mixed may be reduced, and the production efficiency of ashless coal may be reduced. On the other hand, when the average flow rate of the solvent exceeds the upper limit, the moving time of the slurry mixed with the solvent and coal in the line mixer 8 becomes too short, and the line mixer 8 cannot sufficiently extract the solvent-soluble component. There is a fear.

  The solvent supplied to the mixing unit 4 by the pump 11 may be supplied in a turbulent state. By supplying the solvent to the mixing unit 4 in a turbulent state, the solvent violently collides with the coal supplied from the coal supply unit 3 and the coal dissolves faster. Thereby, the extraction time is further shortened and the extraction rate is further improved. Here, the “turbulent flow state” is, for example, a state where the Reynolds number Re is 2100 or more, and more preferably a state where the Reynolds number Re is 4000 or more.

(Preheater)
The preheater 12 is disposed on the downstream side of the solvent supply unit 2 with respect to the pump 11. The preheater 12 heats the solvent pumped by the pump 11. The preheater 12 is not particularly limited as long as it can heat the solvent, but a heat exchanger is generally used as the preheater 12. As the heat exchanger used as the preheater 12, for example, a heat exchanger such as a multi-tube type, a plate type, or a spiral type is used. In the ashless coal manufacturing apparatus 1 shown in FIG. 1, the solvent pumped by the pump 11 is heated, but the solvent previously heated by the preheater 12 may be pumped by the pump 11. . That is, the arrangement of the pump 11 and the preheater 12 in FIG. 1 may be reversed.

  Here, the temperature (extraction temperature) of the slurry at which a high extraction rate is obtained in the mixing unit 4 is about 300 ° C. or higher and 420 ° C. or lower. Therefore, it is preferable to supply a solvent having a temperature such that the slurry mixed with coal in the mixing unit 4 has this extraction temperature. From this viewpoint, the lower limit of the temperature of the solvent downstream of the preheater 12 is preferably 330 ° C, and more preferably 380 ° C. On the other hand, the upper limit of the temperature of the solvent is preferably 450 ° C and more preferably 430 ° C. When the temperature of the solvent is less than the lower limit, the slurry in which the solvent and coal are mixed in the mixing unit 4 is hardly heated to the extraction temperature, and the bonds between the molecules constituting the coal cannot be sufficiently weakened. The extraction rate may be reduced. On the contrary, if the temperature of the solvent exceeds the upper limit, the temperature of the slurry becomes too high in the mixing section 4, and recombination of pyrolysis radicals generated by the pyrolysis reaction of coal occurs, which may reduce the extraction rate. There is. The solvent temperature downstream of the preheater 12 means the temperature of the solvent immediately before being supplied to the mixing unit 4.

  The preheater 12 is heated so that the solvent flowing in the supply pipe 9 reaches the temperature in the above range while passing through the preheater 12. Although the heating time in the preheater 12 is not specifically limited, For example, it is 10 minutes or more and 30 minutes or less. Moreover, the temperature of the solvent before passing the preheater 12 is about 100 degreeC. Therefore, it is preferable that the preheater 12 can heat the solvent at a heating rate of about 10 ° C. or more and 100 ° C. or less per minute.

  The preheater 12 preferably heats the solvent under high pressure. Although it depends on the vapor pressure of the solvent, the lower limit of the pressure when the preheater 12 heats the solvent is preferably 1 MPa and more preferably 2 MPa. On the other hand, the upper limit of the pressure is preferably 5 MPa, more preferably 4 MPa. If the pressure when the preheater 12 heats the solvent is less than the lower limit, the solvent volatilizes and it may be difficult to extract the solvent-soluble component in the mixing step. On the other hand, when the said pressure exceeds the said upper limit, there exists a possibility that an installation cost and an operating cost may increase.

<Coal supply department>
The coal supply unit 3 supplies coal to the mixing unit 4. The coal supply unit 3 includes a normal pressure hopper 13 used in a normal pressure state, a pressure hopper 14 used in a normal pressure state and a pressure state, and a pipe connecting the normal pressure hopper 13 and the pressure hopper 14. And a second valve 16 disposed in a pipe connecting the pressurizing hopper 14 and the supply pipe 9 of the mixing unit 4. A pressurization line 17 that supplies a gas such as nitrogen gas and an exhaust line 18 that exhausts the gas are connected to the pressurization hopper 14.

  The coal stored in the normal pressure hopper 13 is first transferred to the pressure hopper 14 by opening the first valve 15 with the second valve 16 closed. At this time, the pressure hopper 14 is in a normal pressure state. Next, the first valve 15 is closed and a gas such as nitrogen gas is supplied to the pressurization hopper 14 through the pressurization line 17. As a result, the piping from the first valve 15 to the second valve 16 including the pressure hopper 14 is pressurized, and the inside of the pressure hopper 14 is in a pressurized state. At this time, it is preferable to apply pressure so that the pressure in the pressure hopper 14 is equal to or higher than the pressure in the supply pipe 9. The coal in the pressure hopper 14 is supplied to the supply pipe 9 by opening the second valve 16. Since the inside of the pressure hopper 14 is in a pressurized state in this way, the coal in the pressure hopper 14 is smoothly supplied to the supply pipe 9. In the coal supply unit 3 of FIG. 1, the pressurization line 17 and the exhaust line 18 are connected to the pressurization hopper 14, but if it is between the first valve 15 and the second valve 16, the pressurization hopper It may be connected to piping other than 14.

  Here, the types of the first valve 15 and the second valve 16 are not particularly limited, but as the first valve 15 and the second valve 16, for example, a gate valve, a ball valve, a flap valve, a rotary valve, or the like can be used. Can be used.

  As coal supplied from the coal supply part 3, various quality coal can be used. For example, bituminous coal with a high extraction rate 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 3. 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 lump coal has a larger coal particle size than finely pulverized coal, the separation speed in the solution separation step is increased, and the sedimentation separation 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 3 from a viewpoint of shortening of extraction time. As a minimum of the ratio of inferior quality coal to the whole quantity of coal to supply, 80 mass% is preferred and 90 mass% is more preferred. If the ratio of inferior coal contained in the supplied coal is less than the above lower limit, the time for extracting the solvent-soluble component becomes long, and there is a possibility that sufficient extraction cannot be performed by the line mixer 8.

  The lower limit of the carbon content of the inferior coal is preferably 70% by mass. Moreover, as an upper limit of the carbon content rate of the said inferior coal, 85 mass% is preferable and 82 mass% is more preferable. When the carbon content of the inferior coal is less than the lower limit, the extraction rate of the solvent-soluble component may be reduced. On the other hand, when the carbon content of the inferior coal exceeds the upper limit, the cost of supplied coal may increase.

  In addition, as coal supplied to the mixing part 4 from the coal supply part 3, you may use the coal which mixed a small amount of solvent and made it slurry. By supplying the slurried coal from the coal supply unit 3 to the mixing unit 4, the coal is easily mixed with the solvent in the mixing unit 4, and the coal can be dissolved more quickly. However, if the amount of the solvent to be mixed at the time of slurrying is large, it becomes difficult for the line mixer 8 to raise the slurry to the extraction temperature, and the extraction rate may decrease.

<Mixing section>
The mixing unit 4 mixes the solvent supplied from the solvent supply unit 2 and the coal supplied from the coal supply unit 3. The mixing unit 4 has a line mixer 8 connected to a supply pipe 9.

(Line mixer)
The line mixer 8 mixes the solvent supplied through the supply pipe 9 and the coal supplied from the coal supply unit 3 while transporting. Since the solvent supplied to the line mixer 8 is heated by the solvent supply unit 2 and has a high temperature, the coal mixed with the high-temperature solvent is rapidly heated in the line mixer 8. Here, “rapid temperature rise” means heating at a heating rate of 10 ° C. or more and 100 ° C. or less per second, for example, and is faster than the heating rate in the preheater 12. The solvent supplied to the line mixer 8 is heated to a temperature higher than the extraction temperature, but when mixed with coal, the heat of the solvent is used to raise the temperature of the coal, so the temperature of the slurry is preheated. The temperature is lower than the temperature of the solvent heated in the vessel 12. As a result, the temperature of the slurry in which the solvent and coal are mixed in the line mixer 8 becomes the extraction temperature (about 300 ° C. or more and about 420 ° C. or less) within a few seconds to a few tens seconds.

  In the line mixer 8, it is preferable that the temperature of the coal is increased so that the temperature of the slurry in which the coal and the high-temperature solvent are mixed becomes the extraction temperature. Specifically, the lower limit of the temperature of the slurry in which the solvent and coal are mixed is preferably 300 ° C, and more preferably 350 ° C. On the other hand, the upper limit of the temperature of the slurry is preferably 420 ° C., more preferably 400 ° C. When 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 extraction rate may decrease. On the other hand, when the temperature of the slurry exceeds the upper limit, recombination of pyrolysis radicals generated by the pyrolysis reaction of coal occurs, which may reduce the extraction rate.

  The said line mixer 8 should just be what can mix the solvent and coal supplied in a short time, for example, a static mixer, a dynamic mixer, an element lamination type mixer, a multi-line mixer etc. can be used.

  The static mixer has, for example, a plurality of elements in a twisted blade shape (a shape obtained by twisting a rectangular plate with a predetermined twist angle around the longitudinal central axis), and an outer peripheral end face of the twisted blade-shaped element A material in which the (long rectangular side portion) is joined to the inner peripheral surface of the tube and disposed in the tube can be used. Specifically, as the static mixer, for example, a static mixer “N16” manufactured by Noritake Company Limited, a static mixer manufactured by Kenics, a sulzer static mixer SMF type manufactured by Sulzer, or the like can be used.

  The static mixer can adjust the shape and number of elements arranged in a line in the pipe corresponding to the supplied solvent and coal. In the static mixer having the above-described structure, the shape can be adjusted by, for example, arranging adjacent elements in a tube while being rotated by a certain angle (for example, 90 °), or changing the twist angle of each element.

  As the dynamic mixer, a rotary dynamic mixer, a vibro mixer, or the like can be used.

  The material of the portion in contact with the slurry in the line mixer 8 (for example, the inner wall surface and element of the static mixer) is not particularly limited, but a material that hardly corrodes is preferable. For example, it is preferable to use a stainless steel line mixer such as SUS304 or SUS316.

<Solid-liquid separation unit>
The solid-liquid separation unit 5 is directly connected to the discharge port of the line mixer 9 and separates the solution in which the solvent-soluble component is dissolved from the slurry discharged from the line mixer 9. That is, the said ashless coal manufacturing apparatus 1 does not have an extraction tank for extracting a solvent soluble component.

  Specifically, the separation of the solution in the solid-liquid separation unit 5 is a solid content including a solution in which a solvent-soluble component is dissolved from a slurry in which a solvent and coal are mixed in the mixing unit 4 and a solvent-insoluble component by a gravity sedimentation method. Separated into concentrate. 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 solvent-insoluble component is an extraction residue mainly composed of ash and insoluble coal that are insoluble in the solvent, and also includes the solvent used for extraction.

  The ashless coal production apparatus 1 discharges a solution containing a solvent-soluble component from above while continuously supplying slurry from the line mixer 8 into the solid-liquid separation unit 5, and concentrates the solid content containing a solvent-insoluble component. The liquid can be discharged from the lower part. Thereby, continuous solid-liquid separation processing becomes possible.

  The solution containing the solvent-soluble component accumulates at the upper part of the solid-liquid separation unit 5. This solution is filtered through a filter unit (not shown) as necessary, and then discharged to the first solvent separation unit 6. On the other hand, the solid concentrate containing the solvent-insoluble component is collected at the lower part of the solid-liquid separation unit 5 and discharged to the second solvent separation unit 7.

  Although the time which maintains a slurry in the solid-liquid separation part 5 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 5 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 5 can be shortened.

  The solid-liquid separation unit 5 is preferably heated and pressurized. As a minimum of heating temperature in solid-liquid separation part 5, 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 5, 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 5, 1 Mpa is preferable and 1.7 Mpa is more preferable. On the other hand, the upper limit of the pressure is preferably 3 Mpa, and more preferably 2.3 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 5.

<First solvent separation unit>
The first solvent separator 6 evaporates and separates the solvent from the solution separated by the solid-liquid separator 5 to obtain ashless coal (HPC).

  Here, 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. The separated and recovered solvent can be circulated to a pipe upstream of the preheater 12 and repeatedly used. By separating and recovering the solvent from the solution, ashless coal substantially free of ash can be obtained from the solution.

  The ashless coal thus obtained has an ash content of 5% by mass or less or 3% by mass or less, hardly contains 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.

<Second solvent separation unit>
The second solvent separation unit 7 evaporates and separates the solvent from the solid concentrate separated by the solid-liquid separation unit 5 to obtain byproduct charcoal (RC).

  Here, 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 6. The separated and recovered solvent can be circulated to a pipe upstream of the preheater 12 and repeatedly used. 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. 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.

<Advantages>
In the ashless coal production apparatus, coal and a heated solvent are mixed by a line mixer, so the coal is rapidly heated and the slurry in which the solvent and the coal are mixed becomes high temperature, and the solvent is soluble in the line mixer. Ingredients can be extracted. Thereby, the extraction tank used for extraction can be omitted, and the equipment cost can be reduced.

  Moreover, since the said ashless coal manufacturing apparatus extracts the said solvent soluble component, conveying the slurry with which the said solvent and coal were mixed with a line mixer, it can shorten the extraction time of the said solvent soluble component.

  Further, the ashless coal production apparatus does not heat the slurry in which the solvent and coal are mixed as in the conventional ashless coal production apparatus, but only heats the solvent and mixes the heated solvent with coal. Raise the temperature of the coal. Since the solvent is easier to handle than the slurry, and heating only the solvent is easier than heating the slurry, the ashless coal production apparatus is excellent in handling in this respect.

[Production method of ashless coal]
The method for producing ashless coal is a method for producing ashless coal that obtains ashless coal from a slurry obtained by mixing coal and a solvent. The method for producing ashless coal includes a step of heating and supplying a solvent (solvent supply step), a step of supplying coal (coal supply step), and a step of mixing the solvent and coal with a line mixer (mixing step). ), A step of separating the solution in which the coal component is dissolved from the slurry in which the solvent and the coal are mixed (separation step), and a step of obtaining ashless coal by evaporation separation of the solvent from the solution separated in the separation step (Ashless coal acquisition step) and a step of obtaining by-product coal by evaporation of the solvent from the solid concentrate separated in the separation step (by-product coal acquisition step). Hereinafter, the manufacturing method of the said ashless coal using the ashless coal manufacturing apparatus 1 of FIG. 1 is demonstrated.

<Solvent supply process>
In the solvent supply step, the solvent is heated and supplied to the mixing unit 4. Specifically, the solvent stored in the solvent tank 10 is pumped to the mixing unit 4 via the supply pipe 9 by the pump 11. At this time, the solvent flowing in the supply pipe 9 is heated to a temperature higher than the extraction temperature by the preheater 12 disposed in the supply pipe 9 between the pump 11 and the mixing unit 4. Thereby, the heated solvent is supplied to the mixing unit 4.

<Coal supply process>
In the coal supply step, the coal stored in the coal supply unit 3 is supplied to the mixing unit 4. At this time, coal is supplied to the mixing unit 4 in a state where the inside of the pressure hopper 14 is pressurized so that the solvent can be smoothly supplied into the supply pipe 9 connected to the mixing unit 4.

<Mixing process>
In the mixing step, the line mixer 8 mixes the solvent supplied from the solvent supply unit 2 and the coal supplied from the coal supply unit 3 while transporting. When the solvent and coal are supplied, the coal is rapidly heated by the heated solvent, and the slurry mixed with the solvent and coal becomes the extraction temperature. Thereby, the solvent-soluble component is extracted in the line mixer 8.

<Separation process>
In the separation step, the solution in which the solvent-soluble component is dissolved and the solid content concentrate containing the solvent-insoluble component are separated from the slurry mixed in the mixing step. Specifically, the slurry discharged from the line mixer 8 is supplied, and the slurry supplied by, for example, a gravity sedimentation method in the solid-liquid separation unit 5 is separated into the solution and the solid concentrate.

<Ashless coal acquisition process>
In the ashless coal acquisition step, ashless coal is obtained from the solution separated in the separation step by evaporative separation. Specifically, the solution separated by the solid-liquid separation unit 5 is supplied to the first solvent separation unit 6, and the solvent is evaporated by the first solvent separation unit 6 to separate the solvent and ashless coal.

<By-product coal acquisition process>
In the by-product charcoal acquisition step, by-product coal is obtained by evaporation separation from the solid content concentrate separated in the separation step. Specifically, the solid concentration liquid separated by the solid-liquid separation unit 5 is supplied to the second solvent separation unit 7, and the solvent is evaporated by the second solvent separation unit 7 to separate the solvent into by-product coal. .

<Advantages>
In the method for producing ashless coal, the solvent is heated and supplied in the solvent supply step, and the coal and the heated solvent are mixed by the line mixer in the mixing step. Accordingly, the coal supplied in the mixing step is rapidly heated by being mixed with the heated solvent, and the slurry in which the solvent and the coal are mixed becomes high temperature. Thus, the solvent-soluble component can be extracted in the line mixer. As a result, the extraction tank used for extraction can be omitted by the method for producing ashless coal, and the equipment cost can be reduced.

[Second Embodiment]
The ashless coal production apparatus 21 of FIG. 2 further includes an extraction tank 22 that stores the slurry discharged from the mixing unit 4 in addition to the ashless coal production apparatus 1 of FIG. 1. Since the ashless coal production apparatus 21 has the same configuration as the ashless coal production apparatus 1 of FIG. 1 except that it includes an extraction tank 22, the explanation is given with the same reference numerals except for the extraction tank. Omitted.

<Extraction tank>
The extraction tank 22 is supplied with the slurry discharged from the line mixer 8 and stores the slurry for a predetermined time.

  The extraction tank 22 has a stirrer 22a. The extraction tank 22 extracts the solvent-soluble component by holding the supplied slurry at a predetermined temperature while stirring with the stirrer 22a.

  As described in the first embodiment, the solvent-soluble component is extracted in the line mixer 8. However, the extraction time varies depending on the type of coal, temperature, pressure, and the like, and the line mixer 8 may not be able to extract sufficiently. In such a case, the ashless coal production apparatus 21 further extracts the solvent soluble component from the extraction tank 22 with respect to the slurry mixed with the line mixer 8 and extracted with the solvent soluble component.

  Since the extraction of the solvent-soluble component is proceeding in the line mixer 8, the extraction time in the extraction tank 22 is shorter than the conventional extraction time in which the prepared slurry is supplied to the extraction tank without going through the line mixer 8. Is done. Therefore, the ashless coal manufacturing apparatus 21 can make the extraction tank 22 smaller than the conventional extraction tank.

  As a minimum of the predetermined temperature (heating temperature) which hold | maintains a slurry with the said extraction tank 22, 300 degreeC is preferable and 350 degreeC is more preferable. On the other hand, the upper limit of the heating temperature of the slurry is preferably 420 ° C., more preferably 400 ° C. When the heating temperature of the slurry is less than the lower limit, the bond between the molecules constituting the coal cannot be sufficiently weakened, and the extraction rate may be reduced. On the contrary, when the heating temperature of the slurry exceeds the upper limit, coal pyrolysis reaction becomes very active and recombination of generated pyrolysis radicals occurs, which may reduce the extraction rate.

  In addition, it is preferable to perform the heat extraction of the slurry in the extraction tank 22 in a non-oxidizing atmosphere. Specifically, it is preferable to perform heat extraction of the slurry in the presence of an inert gas such as nitrogen. By using an inert gas such as nitrogen, it is possible to prevent the slurry from coming into contact with oxygen and igniting at low cost during the heat extraction.

  The pressure during the heat extraction of the slurry depends on the heating temperature and the vapor pressure of the solvent used, but can be, for example, 1 MPa or more and 3 MPa or less. When the pressure at the time of heat extraction is lower than the vapor pressure of the solvent, the solvent may volatilize and the solvent-soluble component may not be sufficiently extracted. On the other hand, if the pressure at the time of heating extraction is too high, the cost of the equipment, the operating cost, etc. increase.

<Advantages>
The said ashless coal manufacturing apparatus extracts a solvent soluble component more reliably with a line mixer and an extraction tank. Thereby, extraction time of a solvent soluble component can be shortened and an extraction tank can be reduced in size.

[Other Embodiments]
In addition, the solid-liquid separation apparatus and solid-liquid separation method of this invention are not limited to the said embodiment.

  That is, a plurality of line mixers may be connected in series or in parallel according to conditions such as the type of coal, temperature, pressure, and the like. As described above, the extraction time of solvent-soluble components varies depending on the type of coal, temperature, pressure, etc., but by shortening the path for transporting the slurry in the line mixer, the extraction tank can be omitted or downsized. it can.

  In addition, the coal supply unit is not limited to the above-described configuration, and the coal supply unit can smoothly supply coal to the supply pipe while preventing the solvent from flowing backward from the supply pipe to the coal supply unit. A configuration other than the coal supply unit 3 shown in FIG.

  As described above, the ashless coal production apparatus and the ashless coal production method can shorten the extraction time of solvent-soluble components and reduce the size of the equipment for extraction, so when obtaining ashless coal from coal. The apparatus and method can be suitably used.

DESCRIPTION OF SYMBOLS 1 Ashless coal manufacturing apparatus 2 Solvent supply part 3 Coal supply part 4 Mixing part 5 Solid-liquid separation part 6 1st solvent separation part 7 2nd solvent separation part 8 Line mixer 9 Supply pipe 10 Solvent tank 11 Pump 12 Preheater 13 Regular Pressure hopper 14 Pressure hopper 15 1st valve 16 2nd valve 17 Pressure line 18 Exhaust line 21 Ashless coal production device 22 Extraction tank 22a Stirrer

Claims (5)

A mixing section for mixing the solvent and coal;
The solvent is heated to 330 ° C. or higher and 450 ° C. or lower, and the heated solvent is supplied to the mixing section in a turbulent state with an average flow rate of 0.5 m / s to 4 m / s and a Reynolds number Re of 2100 or higher. A supply section;
A coal supply unit for supplying the coal to the mixing unit;
A solid-liquid separation unit for separating the solution in which the coal component is dissolved from the slurry in which the solvent and the coal are mixed;
A solvent separation unit for obtaining ashless coal by evaporation of the solvent from the solution separated by the solid-liquid separation unit,
An apparatus for producing ashless coal in which the mixing unit has a line mixer.   The apparatus for producing ashless coal according to claim 1, wherein a discharge port of the line mixer is directly connected to the solid-liquid separation unit.   The apparatus for producing ashless coal according to claim 1, further comprising an extraction tank for storing slurry discharged from the line mixer. The manufacture of ashless coal according to claim 1 , wherein the coal supplied from the coal supply unit contains 80% by mass or more of inferior coal having a carbon content of 70% by mass or more and 85% by mass or less. apparatus. An ashless coal manufacturing method for obtaining ashless coal from a slurry obtained by mixing coal and a solvent with a mixing device,
Heating the solvent to 330 ° C. to 450 ° C. , and supplying the heated solvent to the mixing device in a turbulent state with an average flow rate of 0.5 m / s to 4 m / s and a Reynolds number Re of 2100 or more ; ,
Supplying the coal to the mixing device;
Mixing the solvent and the coal with the mixing device;
Separating the solution in which the coal component is dissolved from the slurry in which the solvent and the coal are mixed;
A step of obtaining ashless coal by evaporation of the solvent from the solution separated in the separation step,
A method for producing ashless coal, wherein the mixing device is a line mixer.

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