JP6203690B2 - Ashless coal manufacturing apparatus and ashless coal manufacturing method - Google Patents

Description

  The present invention relates to an ashless coal production apparatus and an ashless coal production method for obtaining ashless coal from which ash is removed from coal.

  As a manufacturing method of ashless coal, there exists a thing described in patent documents 1, for example. This ashless coal manufacturing method includes a coal mixing step in which coal and a solvent are mixed to prepare a slurry, and an extraction step in which the slurry obtained in the coal mixing step is heated to extract a coal component soluble in the solvent. And a separation step of separating the solution containing the coal component from the slurry from which the coal component is extracted in the extraction step, and an ashless coal (HPC) for separating the solvent from the solution separated in the separation step And an acquisition step.

JP 2009-227718 A

  As described above, ashless coal is obtained by separating a solvent from a solution containing a coal component soluble in the solvent. Therefore, the yield of ashless coal depends on the proportion of coal components soluble in the solvent (hereinafter also referred to as extraction rate), and this improvement in extraction rate is an important issue in the ashless coal production process. Yes. For example, Patent Document 1 uses a non-hydrogen-donating solvent excellent in affinity with coal as a solvent and increases the extraction rate by setting the extraction temperature and extraction time to desired values. Further improvement is desired.

  An object of the present invention is to provide an apparatus for producing ashless coal and a method for producing ashless coal that can improve the yield of ashless coal.

  The term “yield” as used herein refers to, for example, the ratio of the mass of manufactured ashless coal to the mass of coal as a raw material, and may be referred to as “production efficiency”.

  The apparatus for producing ashless coal in the present invention includes a preheater for heating a solvent, an extraction tank for extracting a coal component soluble in the solvent from a slurry obtained by mixing coal and the solvent, and the coal component A separator for separating the coal component-containing solution from the extracted extraction slurry; and a solvent separator for evaporating and separating the solvent from the solution separated by the separator to obtain ashless coal. In the ashless coal manufacturing apparatus, the solvent and the solvent are supplied to the solvent supply pipe for supplying the solvent heated by the preheater into the extraction tank, and to the solvent supply pipe and the extraction tank. And a slurry supply device for supplying a slurry obtained by mixing the two.

  The method for producing ashless coal in the present invention includes a heating step for heating a solvent, and a solvent supply step for supplying the solvent heated in the heating step into an extraction tank via a solvent supply pipe. And a slurry supply step of supplying a slurry obtained by mixing coal and the solvent to the heated solvent of at least one of the solvent supply pipe and the extraction tank, and the slurry supplied in the slurry supply step In the extraction step of extracting the coal component soluble in the solvent from the slurry, the separation step of separating the solution containing the coal component from the extraction slurry from which the coal component has been extracted in the extraction step, and the separation step And an ashless coal obtaining step of obtaining ashless coal by evaporating and separating the solvent from the separated solution.

  According to the present invention, the yield of ashless coal can be improved.

It is a schematic diagram of the manufacturing apparatus of ashless coal. It is a schematic diagram of a slurry transfer test apparatus.

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

(Configuration of ashless coal production equipment)
As shown in FIG. 1, which is a schematic diagram, an apparatus for producing ashless coal according to an embodiment of the present invention includes a solvent tank 2, a transfer pump 4, a preheater 5, an extraction tank 6 in order from the upstream side of the production process. A gravity settling tank (separator) 7 and solvent separators 8 and 9 are provided. The solvent tank 2 and the preheater 5 are connected by a solvent transfer pipe 10. The preheater 5 and the extraction tank 6 are connected by a solvent supply pipe 11. The ashless coal production apparatus 100 includes a coal hopper 12 and a slurry supply device 14 on the upstream side of the extraction tank 6, in a system separate from the solvent transfer pipe 10 and the solvent supply pipe 11.

(Transfer pump)
The transfer pump 4 conveys the solvent stored in the solvent tank 2 to the extraction tank 6 through the solvent transfer pipe 10 and the solvent supply pipe 11, and is provided in the solvent transfer pipe 10. The solvent is transferred to the extraction tank 6 by the transfer pump 4 in a turbulent state, for example. The “turbulent state” in the present application refers to a state where the Reynolds number Re is 2100 or more, for example, and more preferably a state where the Reynolds number Re is 4000 or more. The solvent may be conveyed in a laminar flow state, that is, in a state where the Reynolds number Re is less than 2100.

(Preheater)
The preheater 5 heats the solvent conveyed by the transfer pump 4, and is provided between the solvent transfer pipe 10 and the solvent supply pipe 11. The preheater 5 is not particularly limited as long as it can heat the solvent, but a heat exchanger is generally used. The solvent transferred through the solvent transfer pipe 10 is heated by exchanging heat when passing through the preheater 5. In addition, the preheater 5 is capable of heating the solvent at a heating rate of 10 to 100 ° C. per minute, for example, depending on the molecular weight of the solvent. The preheater 5 heats the solvent to 300 to 450 ° C.

  In the present embodiment, the solvent transported by the transfer pump 4 is heated, but the solvent previously heated by the preheater 5 may be transported by the transfer pump 4. That is, the arrangement of the transfer pump 4 and the preheater 5 may be reversed. In this case, the transfer pump 4 is provided in the solvent supply pipe 11.

(Solvent supply pipe)
The solvent supply pipe 11 supplies the solvent heated by the preheater 5 into the extraction tank 6. The solvent heated by the preheater 5 passes through the solvent supply pipe 11 and is supplied into the extraction tank 6 in a turbulent state, for example.

(Slurry supply device)
The slurry supply device 14 supplies slurry into the extraction tank 6, and is provided in a separate system from the solvent transfer pipe 10 and the solvent supply pipe 11. By supplying the slurry into the extraction tank 6 from the slurry supply device 14, the solvent heated in the extraction tank 6 and the slurry are mixed in the extraction tank 6.

  The slurry supply device 14 includes a mixer 15, a hopper 16, and a pump 17.

  The mixer 15 mixes the coal supplied from the coal hopper 12 and the solvent supplied from the solvent tank 2 to prepare a slurry. Note that the solvent may be supplied to the mixer 15 from a solvent tank provided separately from the solvent tank 2. The mixer 15 mixes coal and a solvent at normal pressure and 20-70 degreeC. In this embodiment, coal and a solvent are mixed so that the coal concentration in the slurry after mixing is 40 wt% or more and 70 wt% or less. The slurry prepared by the mixer 15 is fed into the pump 17 from the hopper 16 and supplied to the extraction tank 6 through the pump 17.

  In addition, the slurry supply apparatus 14 is not what supplies the slurry prepared with the mixer 15 in the extraction tank 6 with the pump 17, but the coal concentration in the slurry prepared separately is 40 wt% or more and 70 wt% or less. The slurry may be supplied into the extraction tank 6 by the pump 17. In this case, the mixer 15 becomes unnecessary.

  The pump 17 supplies the slurry prepared by the mixer 15 into the extraction tank 6. Although it does not specifically limit as the pump 17, For example, rotary positive displacement pumps, such as a uniaxial screw pump and a biaxial screw pump, can be used. The rotary positive displacement pump pumps liquid by changing the volume of a pump chamber by the rotational movement of a screw-type rotor. In the present embodiment, the pump 17 is a single screw pump. Uniaxial screw pumps and biaxial screw pumps can continuously transfer a constant volume of slurry without pulsation. The pump 17 supplies the slurry into the extraction tank 6 whose inside is pressurized to 1.0 to 3.0 MPa by pumping the slurry at a pressure equal to or higher than the pressure in the extraction tank 6.

  Here, as a state of the slurry suitable for transferring the slurry by the pump 17 which is a single screw pump, when the slurry is grasped by hand, not only the liquid component is removed from the gap but has fluidity. A state in which the slurry escapes from the gap without separation is preferable. The slurry mixes quickly with the heated solvent in the extraction tank 6 as the slurry is less likely to separate. In addition, coal that is familiar with the solvent dissolves rapidly in the heated solvent as the slurry is more difficult to separate. Therefore, the extraction rate improves as the slurry is more difficult to separate. The state of the slurry varies depending on the particle diameter of coal, coal concentration, stirring conditions, and the like. In this embodiment, coal having a particle size of less than 1 mm and a solvent are mixed at 20 to 70 ° C. and normal pressure, and the coal concentration in the slurry is 40 wt% or more and 70 wt% or less, and it is difficult to separate and is fluid. A slurry is being prepared.

  The pump 17 may be configured to perform slurry preparation and slurry supply, respectively. That is, coal and a solvent are supplied into the pump 17, and both are mixed in the pump 17 to prepare a slurry, and the prepared slurry is supplied into the extraction tank 6 by the pump 17. In this case, the mixer 15 becomes unnecessary.

  Further, the slurry supply device 14 may supply the slurry into the solvent supply pipe 11. In this case, the pump 17 is connected to the solvent supply pipe 11 and supplies the slurry into the solvent supply pipe 11 having a high pressure inside (for example, 1.0 to 5.0 MPa). In this case, as will be described later, the solvent and slurry heated in the extraction tank 6 are not mixed, but the solvent and slurry heated in the solvent supply pipe 11 are mixed. . Note that the slurry supply device 14 may supply the slurry into the extraction tank 6 and the solvent supply pipe 11, respectively.

(Extraction tank)
The extraction tank 6 extracts a coal component soluble in a solvent from a slurry obtained by mixing coal and a solvent (dissolves in a solvent). In this embodiment, the extraction tank 6 extracts a coal component soluble in the solvent from a slurry obtained by mixing the solvent heated by the preheater 5 and the slurry supplied from the slurry supply device 14. The high temperature (300 to 450 ° C., more preferably 350 to 420 ° C.) solvent supplied from the solvent supply pipe 11 to the extraction tank 6 and the slurry supplied to the extraction tank 6 from the slurry supply device 14 are the extraction tank 6. In the instant mixing. By mixing the heated solvent and the slurry, the temperature of the mixed slurry is rapidly increased. In the present embodiment, the heated solvent and the slurry are mixed so that the temperature of the slurry formed by mixing the solvent and the slurry becomes about 300 to 420 ° C. in several seconds to several tens of seconds.

(Method for producing ashless coal)
Next, the method for producing ashless coal according to the present invention will be described. The method for producing ashless coal according to an embodiment of the present invention includes a transport process, a heating process, a solvent supply process, a slurry supply process, an extraction process, a separation process, and an ashless coal acquisition process. It further has a raw charcoal acquisition process. Hereinafter, each step will be described.

(Conveying process)
The transporting process is a process of transporting the solvent stored in the solvent tank 2 to the subsequent process by the transfer pump 4. As described above, the solvent is conveyed to a subsequent process in, for example, a turbulent state (turbulent).

  Here, the solvent is not particularly limited as long as it dissolves coal, but a bicyclic aromatic compound derived from coal is preferably used. Since the basic structure of this bicyclic aromatic compound is similar to the structural molecule of coal, the affinity with coal is high and a relatively high extraction rate can be obtained. 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.

  Although the boiling point of a solvent is not specifically limited, For example, from a viewpoint of the extraction rate in an extraction process, and the solvent recovery rate in an ashless coal acquisition process or a by-product coal acquisition process, 180-300 degreeC, Especially 230-280 degreeC Are preferably used. On the other hand, when the boiling point of the solvent is lower than 180 ° C., the loss due to volatilization increases when the solvent is recovered in the ashless coal acquisition process or the by-product coal acquisition process, which may reduce the solvent recovery rate. . Moreover, when the boiling point of a solvent exceeds 300 degreeC, isolation | separation with coal and a solvent becomes difficult and there exists a possibility that the recovery rate of a solvent may fall.

(Heating process)
The heating process is a process of heating the solvent conveyed by the transfer pump 4. This heating step is performed by the preheater 5 in FIG. More specifically, heating is performed while the solvent transferred through the solvent transfer pipe 10 passes through the preheater 5. The temperature of the solvent heated by the preheater 5 is preferably 300 to 450 ° C, more preferably 350 to 420 ° C, from the viewpoint of improving the extraction rate in the extraction step. Furthermore, the temperature of the solvent heated by the preheater 5 is preferably equal to or higher than the temperature of the slurry in the extraction tank 6 (300 to 420 ° C.) described later. In addition, the temperature of the solvent before passing the preheater 5 is about 100 degreeC. The heating time in the preheater 5 is not particularly limited, but is approximately 10 to 30 minutes. Therefore, the solvent is heated at a heating rate of about 10 to 100 ° C. per minute. The heating step is performed under a high pressure, and the pressure is preferably in the range of 1.0 to 5.0 MPa, although it depends on the vapor pressure of the solvent. This is because if the pressure is not set higher than the vapor pressure of the solvent, the solvent volatilizes and it becomes difficult to extract coal in the extraction process.

  Here, the temperature of the solvent heated by the preheater 5 refers to the temperature of the solvent flowing in the solvent supply pipe 11. It can also be said to be the temperature of the solvent immediately before mixing with the slurry supplied to the extraction tank 6 from the slurry supply device 14.

  When the slurry is supplied into the solvent supply pipe 11 by the slurry supply device 14, the temperature of the solvent heated by the preheater 5 is higher than the solvent supply pipe 11 upstream of the connection portion with the pump 17. The temperature of the solvent flowing inside.

  In this embodiment, the heating process is performed after the conveying process, but the heating process is performed before the conveying process by changing the order of the transfer pump 4 and the preheater 5, for example. May be.

(Solvent supply process)
The solvent supply step is a step of supplying the solvent heated by the preheater 5 into the extraction tank 6 via the solvent supply pipe 11. The heated solvent is conveyed into the extraction tank 6 in, for example, a turbulent state (turbulent).

  In addition, when a heating process is performed before a conveyance process, a conveyance process is included in a solvent supply process.

(Slurry supply process)
The slurry supply step is a step of supplying the slurry into the heated solvent in the extraction tank 6. The slurry supply step is performed by the slurry supply device 14 in FIG. The slurry supply process has a coal mixing process and a slurry transfer process.

(Coal mixing process)
The coal mixing step is a step of preparing a slurry by mixing coal and a solvent. This coal mixing step is performed by a mixer 15 in FIG. Coal which is a raw material is charged into the mixer 15 from the coal hopper 12 and a solvent is charged into the mixer 15 from the solvent tank 2. The coal and solvent charged in the mixer 15 are mixed to form a slurry composed of coal and solvent.

  As the raw material for the coal, various quality coals can be used. For example, bituminous coal, subbituminous coal, and lignite are preferably used. Further, when coal is classified by particle size, finely pulverized coal is preferably used. “Finely pulverized coal” refers to, for example, coal in which the weight ratio of coal with a particle size of less than 1 mm is 80% or more with respect to the total coal. When verifying the particle size of coal, such as whether the particle size (particle size) of coal is less than 1 mm, for example, a screening test defined in JIS A 1102 can be used. For example, a sieve can be used for separating coal. Coal that has not been finely pulverized may be pulverized to prepare “finely pulverized coal”, or already finely pulverized coal may be procured.

  As a solvent mixed with coal, the same solvent as the solvent that is conveyed from the solvent tank 2 and heated can be used. That is, a bicyclic aromatic compound derived from coal having a boiling point of 180 to 300 ° C, particularly 230 to 280 ° C is preferably used.

  The coal supplied from the coal hopper 12 to the mixer 15 is mixed with a solvent at 20 to 70 ° C. and normal pressure. Here, the coal density | concentration in the slurry of the slurry after mixing is adjusted to 40 wt% or more and 70 wt% or less. The mixing time in the coal mixing step is not particularly limited, but the mixing is performed under such a condition that the slurry is in a state suitable for transfer by the pump 17. That is, they are mixed so as to form a slurry that is difficult to separate and has some fluidity.

  In the slurry supply step, the slurry prepared in the mixer 15 is not supplied into the heated solvent in the extraction tank 6, but the coal concentration in the slurry prepared separately is 40 wt% or more. A slurry of 70 wt% or less may be supplied into the heated solvent in the extraction tank 6. In this case, the coal mixing step is not necessary.

(Slurry transfer process)
The slurry transfer step is a step of supplying the slurry obtained in the coal mixing step into the extraction tank 6. This slurry transfer step is performed by a pump 17 in FIG.

  In the slurry supply process, the slurry obtained in the coal mixing process may be supplied into the heated solvent in the solvent supply pipe 11, or in the extraction tank 6 and the solvent supply pipe 11. You may supply each in the heated solvent.

(Extraction process)
The extraction step is a step of extracting (dissolving in a solvent) coal components soluble in the solvent from the slurry supplied in the slurry supply step. This extraction process is performed in the extraction tank 6 in FIG. More specifically, the slurry is supplied into the heated solvent in the extraction tank 6 and mixed instantaneously. After mixing, extraction is performed while being held at a predetermined temperature while being stirred by a stirrer 6a provided in the extraction tank 6. Here, the solvent-soluble component is a coal component that can be dissolved in a solvent, and is mainly derived from an organic component in coal having a relatively small molecular weight and no developed crosslinked structure. In addition, extraction is performed simultaneously with the heated solvent and slurry being mixed. Therefore, when the slurry is supplied into the heated solvent in the solvent supply pipe 11 in the slurry supply step, the extraction is performed in the solvent supply pipe 11.

  Here, the high-temperature (300 to 450 ° C., more preferably 350 to 420 ° C.) solvent supplied to the extraction tank 6 through the solvent supply pipe 11 and the slurry supplied to the extraction tank 6 by the pump 17 are mixed. Thus, the temperature of the mixed slurry is rapidly increased. “Rapid heating” means heating at a heating rate of 10 to 500 ° C. per second, for example, which is faster than the heating rate in the preheater 5. As a result, the temperature of the slurry formed by mixing the heated solvent and the slurry becomes about 300 to 420 ° C. in several seconds to several tens of seconds (note that the sensible heat of coal and the temperature of the slurry are Lower than the temperature of the heated solvent). When the temperature of the slurry is rapidly raised, the softening and melting characteristics (fluidity) of the coal in the slurry is improved, so that the coal becomes fluidized quickly and mixes well with the solvent. As a result, since the coal is suitably dissolved in the solvent, the proportion of the coal component extracted in the extraction tank 6, that is, the extraction rate is improved.

  Here, the slurry as a suspension and the heated solvent are mixed, so that both can be quickly mixed as compared with heating after mixing coal and the solvent. Moreover, since the surface of the coal in the slurry is wet with the solvent, the solvent quickly penetrates into the inside of the coal when the heated solvent comes into contact therewith, whereby the coal can be rapidly dissolved. That is, by supplying a slurry obtained by mixing coal and a solvent in advance into a heated solvent, it is possible to promote dissolution of a coal component that is soluble in the solvent in the slurry. Thereby, not only the coal component that is immediately dissolved by the temperature increase, but also the coal component that is dissolved by slowly aging in the extraction tank 6 after the temperature increase can be quickly dissolved. As a result, the extraction rate is improved. Thereby, the yield of ashless coal can be improved.

  Further, since the solvent is conveyed in a turbulent state from the transfer pump 4, the solvent violently collides with the slurry supplied into the extraction tank 6. As a result, the coal in the slurry is well dissolved and the extraction rate is improved. Moreover, after mixing, it becomes a slurry in which the solvent and coal are well mixed.

  Moreover, since the ratio of the extracted coal component increases by extracting a coal component from the slurry whose coal concentration is 40 wt% or more and 70 wt% or less, an extraction rate can be improved further.

  Moreover, since the surface area of a coal particle becomes large by using coal with a particle diameter of less than 1 mm as a raw material, the coal in a slurry becomes easy to melt | dissolve with a high temperature solvent in an extraction process. Thereby, an extraction rate can be improved further.

  The temperature of the slurry in the extraction step is 300 to 420 ° C., more preferably 350 to 400 ° C., from the viewpoint of improving the extraction rate. That is, the temperature of the solvent in the heating process is maintained in the extraction process. If the temperature is lower than 300 ° C., it is not sufficient to weaken the bonds between the molecules constituting the coal, and the extraction rate decreases. On the other hand, even when the temperature is higher than 420 ° C., the pyrolysis reaction of coal becomes active, and recombination of the generated pyrolysis radical occurs, so that the extraction rate decreases. At 300 to 420 ° C., the bonds between the molecules constituting the coal are loosened, mild thermal decomposition occurs, and the extraction rate becomes high. In particular, at 350 to 400 ° C., the extraction rate becomes the highest.

  The extraction process is performed in the presence of an inert gas. The inert gas used in the extraction step is not particularly limited, but it is preferable to use inexpensive nitrogen. Moreover, although the pressure in an extraction process is based also on the temperature in the case of extraction, and the vapor pressure of the solvent to be used, the range of 1.0-3.0 MPa is preferable. Although the heating time (extraction time) in an extraction process is not specifically limited, From the viewpoint of obtaining sufficient dissolution and a sufficient extraction rate, a range of 5 to 60 minutes is preferable, and a range of 20 to 40 minutes is more preferable. .

(Separation process)
In the separation step, the extracted slurry from which the coal component has been extracted in the extraction step is separated from the solution in which the coal component soluble in the solvent is dissolved, for example, by gravity precipitation, and the coal component insoluble in the solvent (solvent insoluble component, for example, ash ) Is a separated solid concentrate (solvent insoluble component concentrate). This separation step is performed in the gravity settling tank 7 in FIG. The gravitational sedimentation method is a separation method in which a solid content is settled and separated using gravity. While the extraction slurry is continuously fed into the tank, the solution containing solvent-soluble components can be discharged from the top and the solid concentrate containing solvent-insoluble components can be discharged from the bottom, allowing continuous separation processing. It becomes. Here, the solvent-insoluble component is a coal component such as ash remaining without being dissolved in the solvent or coal containing the ash even if the coal component is extracted with a solvent, and has a relatively large molecular weight and a crosslinked structure. It is derived from developed organic components.

  The solution containing the solvent-soluble component accumulates in the upper part of the gravity sedimentation tank 7, and is filtered by a filter unit (not shown) as necessary, and then discharged to the solvent separator 8. On the other hand, the solid concentrate containing the solvent-insoluble component is collected in the lower part of the gravity settling tank 7 and discharged to the solvent separator 9. The separation method is not limited to the gravity sedimentation method, and may be separated by, for example, a filtration method or a centrifugal separation method. In that case, a filter, a centrifuge, etc. are used as a separation device.

  The time for maintaining the extraction slurry in the gravity sedimentation tank 7 is not particularly limited, but the sedimentation can be performed in about 30 to 120 minutes.

  The gravity sedimentation tank 7 is preferably heated and pressurized in order to prevent reprecipitation of solvent-soluble components. The heating temperature is preferably in the range of 300 to 420 ° C., and the pressure is preferably in the range of 1.0 to 3.0 MPa, more preferably in the range of 1.7 to 2.3 MPa.

(Ashless coal acquisition process)
The ashless coal acquisition step is a step of obtaining ashless coal (HPC) by evaporating and separating the solvent from the solution (supernatant liquid) containing the solvent-soluble component separated in the separation step. This ashless coal acquisition step is performed by the solvent separator 8 in FIG. The evaporative separation is a separation method including a general distillation method, an evaporation method (spray drying method, etc.) and the like. The separated and recovered solvent can be circulated to the solvent transfer pipe 10 and used repeatedly. Moreover, it can return to the mixer 15 and can be used repeatedly. By separating and collecting the solvent, ashless coal (HPC) substantially free of ash can be obtained from the solution.

  Ashless coal contains almost no ash, has no moisture, and exhibits a higher calorific value than raw coal. Furthermore, softening meltability (fluidity), which is a particularly important quality as a raw material for coke for iron making, has been greatly improved, and the obtained ashless coal (HPC) is good even if the raw coal does not have softening meltability Soft meltability. Therefore, ashless coal can be used as a blended coal for coke raw materials. The ashless coal means ash content of 5% by weight or less, preferably 3% by weight or less.

(By-product coal acquisition process)
The by-product coal acquisition step is performed as necessary, and a step of obtaining a by-product coal (also referred to as RC or residual coal) by evaporating and separating the solvent from the solid content concentrate containing the solvent-insoluble component separated in the separation step. It is. This byproduct charcoal acquisition process is implemented by the solvent separator 9 in FIG.

  As a method for separating the solvent from the solid concentrate, a separation method including a general distillation method, an evaporation method (spray drying method, etc.) and the like can be used as in the above-described ashless coal acquisition step. The separated and recovered solvent can be circulated to the solvent transfer pipe 10 and used repeatedly. Moreover, it can return to the mixer 15 and can be used repeatedly. By separating and recovering 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 coal does not exhibit softening and melting properties, but the oxygen-containing functional groups are eliminated, so that when used as a blended coal, it inhibits the softening and melting properties of other coals contained in this blended coal. Not something. Therefore, this byproduct charcoal can also be used as a part of the coal blend of the coke raw material. The by-product coal may be discarded without being collected.

(Slurry preparation test)
Next, a slurry was prepared using coal having different particle diameters, and the conditions for achieving a slurry state suitable for transfer by the pump 17 were examined. Specifically, using coal having different particle diameters, stirring was performed at a stirring speed of 100 rpm under normal temperature and pressure to prepare a slurry having a coal concentration of 60 to 65 wt%. At that time, the stirring time was varied from 0 to 120 minutes, and the state of the slurry was confirmed. The results are shown in Table 1. In Table 1, “△” indicates that the transfer by the pump 17 is possible, but everything is not separated but tends to be separated slightly, “◯” is difficult to separate, “◎” is more It means something that was difficult to separate. Here, the more the slurry is more difficult to separate, the faster the heated solvent and the slurry are mixed together, so that sedimentation inside the pump and piping is suppressed, leading to prevention of clogging. In addition, coal that is familiar with the solvent dissolves rapidly in the heated solvent as the slurry is more difficult to separate. Therefore, the extraction rate improves as the slurry is harder to separate.

  From Table 1, it was found that the most suitable slurry for transfer by the pump 17 is that having a coal particle size of less than 150 μm, a coal concentration of 60 wt%, and a stirring time of 60 minutes or more. If such a slurry is used, an extraction rate will improve suitably.

(Slurry transfer test)
Next, the slurry was actually transferred using the slurry transfer test apparatus 200 shown in FIG. Specifically, the slurry charged into the hopper 16 was transferred to the tank 21 by the pump 17 to check the blockage of the pipe 22.

  Here, sample No. in the state of “「 ”in Table 1, that is, the state equivalent to the slurry having a coal particle diameter of less than 150 μm and the coal concentration of 60 wt%, or the state of“ ◯ ”. 1 and no. 2 was prepared and tested at room temperature and normal pressure. Samples are shown in Table 2. As the pump 17, a Heisin Mono pump, which is a uniaxial eccentric screw pump manufactured by Hyojin Equipment Co., Ltd., was used. Further, a mixer having a stirring speed of 750 rpm was used for stirring the slurry. Further, the inside of the tank 21 was set to a pressure condition of 0.10 MPaG.

  Sample No. The slurry No. 1 was obtained by stirring for 30 minutes using coal having a particle size of less than 250 μm, and the coal concentration was 60 wt%. Sample No. The slurry of No. 2 was obtained by stirring for 10 minutes using coal having a particle size of less than 500 μm, and the coal concentration was 60 wt%. These slurries were difficult to separate and had a high fluidity. When these slurries were transferred, clogging did not occur in the pipe 22, and the discharge pressure of the pump 17 was stable at 0.1 to 0.2 MPaG.

  Therefore, although the state of the slurry changes depending on the coal particle diameter, coal concentration, and stirring conditions, it was found that the slurry can be transferred by the pump 17 without clogging if the slurry has high fluidity and is difficult to separate. By continuously transferring such slurry by the pump 17, the extraction rate is preferably improved.

(effect)
As described above, in the present embodiment, the solvent heated by the preheater 5 is supplied into the extraction tank 6, and the slurry obtained by mixing coal and the solvent is supplied into the extraction tank 6. To do. Thereby, the solvent heated in the preheater 5 and the slurry are mixed in the extraction tank 6. By mixing the heated solvent and the slurry, the temperature of the mixed slurry is rapidly increased. When the temperature of the slurry is rapidly raised, the softening and melting characteristics (fluidity) of the coal in the slurry is improved, so that the coal becomes fluidized quickly and mixes well with the solvent. As a result, since the coal is suitably dissolved in the solvent, the ratio of the coal component extracted in the extraction tank, that is, the extraction rate is improved. In addition, the slurry, which is a suspension, and the heated solvent are mixed, so that both can be quickly mixed as compared with heating after mixing coal and solvent. Moreover, since the surface of the coal in the slurry is wet with the solvent, the solvent quickly penetrates into the inside of the coal when the heated solvent comes into contact therewith, whereby the coal can be rapidly dissolved. That is, by supplying a slurry obtained by previously mixing coal and a solvent into a heated solvent, it is possible to promote the dissolution of coal components that are soluble in the solvent in the slurry. The rate is improved. Thereby, the yield of ashless coal can be improved.

  Further, the slurry previously mixed and prepared by the mixer is supplied into the extraction tank 6 by the pump 17. By mixing and adjusting the coal and the solvent in advance, the slurry quickly mixes with the heated solvent in the extraction tank 6, and coal familiar with the solvent rapidly dissolves with the heated solvent. Thereby, an extraction rate can be improved.

  Further, by using a single screw pump or a twin screw pump, the slurry previously mixed and prepared by the mixer 15 can be stably supplied into the extraction tank 6.

  Further, the transfer pump 4 transports the solvent to the extraction tank 6 in a turbulent state. As a result, the turbulent solvent violently collides with the slurry supplied into the extraction tank 6. As a result, the extraction of coal components further proceeds. Further, since the solvent is conveyed in a turbulent state, the solvent and the slurry are well mixed, and the extraction of the coal component proceeds quickly. Therefore, extraction time can be shortened, and apparatus cost and operation cost can be suppressed.

  In addition, the preheater 5 heats the solvent to 300 ° C. or higher and 450 ° C. or lower. Thereby, the temperature of the solvent which flows through the solvent supply pipe | tube 11 will be 300-450 degreeC. Therefore, in the extraction tank 6, it is possible to rapidly raise the temperature of the slurry obtained by mixing the heated solvent and the slurry to about 300 to 420 ° C. that is a temperature at which a high extraction rate is obtained. As a result, the extraction rate can be further improved.

  Further, the solvent is heated by the preheater 5 to a temperature of the slurry in the extraction tank 6 (300 to 420 ° C.) or higher. Thereby, in the extraction tank 6, it becomes possible to instantaneously raise the temperature of a slurry obtained by mixing the heated solvent and the slurry to about 300 to 420 ° C., which is a temperature at which a high extraction rate is obtained. As a result, the extraction rate can be further improved.

  Further, the coal concentration in the slurry is adjusted to 40 wt% or more and 70 wt% or less. By extracting the coal component from the slurry having a high coal concentration, the ratio of the extracted coal component is increased, so that the extraction rate can be further improved.

  Moreover, since the surface area of a coal particle becomes large by using coal with a particle diameter of less than 1 mm as a raw material, the coal in a slurry becomes easy to melt | dissolve with a high temperature solvent in an extraction process. Thereby, an extraction rate can be improved further.

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

DESCRIPTION OF SYMBOLS 2 Solvent tank 4 Transfer pump 5 Preheater 6 Extraction tank 6a Stirrer 7 Gravity sedimentation tank 8,9 Solvent separator 10 Solvent transfer pipe 11 Solvent supply pipe 12 Coal hopper 14 Slurry supply apparatus 15 Mixer 16 Hopper 17 Pump 21 Tank 22 Piping 100 Ashless coal production equipment 200 Slurry transfer test equipment

Claims (6)

A preheater for heating the solvent;
An extraction tank for extracting a coal component soluble in the solvent from a slurry obtained by mixing coal and the solvent;
A separation device for separating the solution containing the coal component from the extraction slurry from which the coal component has been extracted;
A solvent separator for evaporating and separating the solvent from the solution separated by the separation device to obtain ashless coal;
In an ashless coal manufacturing apparatus equipped with
A solvent supply pipe for supplying the solvent heated by the preheater into the extraction tank;
A slurry supply device for supplying a slurry obtained by mixing the coal and the solvent to at least one of the solvent supply pipe and the extraction tank;
An apparatus for producing ashless coal, comprising: The slurry supply apparatus includes:
A mixer for preparing the slurry by mixing the coal and the solvent;
A pump for supplying the slurry from the mixer to at least one of the solvent supply pipe and the extraction tank;
The apparatus for producing ashless coal according to claim 1, comprising:   The ashless coal manufacturing apparatus according to claim 2, wherein the pump is a single screw pump or a twin screw pump. A heating step for heating the solvent;
A solvent supply step of supplying the solvent heated in the heating step into an extraction tank via a solvent supply pipe;
A slurry supply step of supplying a slurry obtained by mixing coal and the solvent to the heated solvent of at least one of the solvent supply pipe and the extraction tank;
An extraction step of extracting coal components soluble in the solvent from the slurry supplied in the slurry supply step;
A separation step of separating the solution containing the coal component from the extraction slurry from which the coal component has been extracted in the extraction step;
Ashless coal acquisition step of obtaining ashless coal by evaporating and separating the solvent from the solution separated in the separation step;
A method for producing ashless charcoal, comprising: The slurry supply step includes
A coal mixing step of preparing the slurry by mixing the coal and the solvent;
A slurry transfer step of supplying the slurry obtained in the coal mixing step into at least one of the solvent supply pipe and the extraction tank;
The method for producing ashless coal according to claim 4, comprising:   The method for producing ashless coal according to claim 4 or 5, wherein the coal having a particle diameter of less than 1 mm is used as a raw material.

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