JP6105334B2 - Gravity sedimentation tank and method for producing ashless coal - Google Patents

Description

  The present invention relates to a gravity settling tank for separating a slurry obtained by mixing and heating coal and a solvent into a solid concentrate and a supernatant, and an ashless coal for obtaining ashless coal from which ash is removed from coal. It relates to a manufacturing method.

  As a manufacturing method of ashless coal, there exist some which were indicated in patent documents 1-3, for example. In these ashless coal production methods, coal and a solvent are mixed to prepare a slurry, and the resulting slurry is heated to extract a coal component that is soluble in the solvent (hereinafter referred to as a solvent-soluble component). The slurry from which the soluble component was extracted was separated into a solution part (supernatant liquid) containing the solvent soluble component and a solid concentrate containing a coal component insoluble in the solvent (hereinafter, solvent insoluble component). The solvent is separated from the solution part to obtain ashless coal. Gravity sedimentation tanks are used in the separation device for separating the slurry into the solution part (supernatant liquid) and the solid content concentrate from the viewpoint of efficient separation.

JP 2009-227718 A JP 2009-214000 A JP 2007-735 A

  By the way, in the extraction process of a solvent soluble component, the temperature of the heated slurry is 300-420 degreeC (refer paragraph 0026 of patent document 1), for example. Under such a high temperature, coal undergoes a pyrolysis reaction to generate gases such as methane, carbon dioxide, and water vapor, and these gases are contained in the slurry as bubbles. When these bubbles are supplied to the gravity settling tank together with the slurry, the bubbles rise while diffusing into the gravity settling tank. Therefore, there arises a problem that the solid content in which bubbles are settled in the lower part of the gravity sedimentation tank is stirred, or the sedimentation of the solid content is disturbed by disturbing the sedimentation of the solid content. As a result, problems such as deterioration of sedimentation efficiency and increase in the amount of ash contained in ashless coal may occur.

  The present invention has been made in view of the above circumstances, and its object is to provide a gravity settling tank capable of suppressing disturbance of sedimentation of solids caused by bubbles generated by a thermal decomposition reaction of coal, and ashless coal using the same. It is to provide a manufacturing method.

In order to solve the above problems, the gravity sedimentation tank of the present invention comprises a pressure vessel that settles solids contained in a slurry obtained by mixing and heating coal and a solvent and separates them into a solid concentrate and a supernatant. A supply pipe that supplies the slurry to the pressure vessel, and a nozzle portion that is formed at a distal end portion of the supply pipe and that discharges the slurry is disposed inside the pressure vessel, and between the nozzle portion so as to have a gap, the outer periphery of the nozzle portion and the outer tube is provided, wherein the nozzle unit, the tip is open, is disposed within a range of ± 45 ° with respect to lead straight direction, The lower end of the outer tube is located below the tip and above the boundary between the solid concentrate layer and the supernatant layer .

  ADVANTAGE OF THE INVENTION According to this invention, the gravity sedimentation tank which can suppress the disorder | damage | failure of sedimentation of solid content by the bubble produced by the thermal decomposition reaction of coal, and the manufacturing method of ashless coal using the same can be provided.

It is the schematic which shows the manufacturing apparatus of the ashless coal which concerns on embodiment of this invention. It is sectional drawing of the gravity settling tank used for the manufacturing apparatus of ashless coal shown in FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. (A) is the 1st modification of the gravity settling tank shown in FIG. 2, (b) is the 2nd modification of the gravity settling tank shown in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an ashless coal production apparatus 1 according to an embodiment of the present invention.

(Configuration of ashless coal production apparatus 1)
The ashless coal manufacturing apparatus 1 includes a slurry preparation tank 2 that prepares a slurry by mixing coal and a solvent, an extraction tank 3 that heats the prepared slurry and extracts a solvent-soluble component, and a solvent-soluble substance. Gravity sedimentation tank 4 that settles the solid content contained in the slurry from which the components have been extracted and separates it into a solid content concentrate and a supernatant (a solution part containing a solvent-soluble component), and a solvent from the separated supernatant. A solvent separator 5 for obtaining ashless coal (HPC) by evaporation and a solvent separator 6 for obtaining by-product coal (RC: Residue coal) by evaporating and separating the solvent from the separated solid concentrate. And have. In addition, the solvent separator 6 is installed as needed and does not need to be.

  Here, the solvent-insoluble component is a coal component (solid content) such as ash remaining without being dissolved in the solvent or coal containing the ash (that is, by-product coal) even when the coal component is extracted with the solvent. Yes, it is derived from an organic component having a relatively large molecular weight and a developed cross-linked structure. On the other hand, a solvent-soluble component is a coal component that can be dissolved in a solvent by extracting the coal with a solvent, and is derived from an organic component in coal that has a relatively low molecular weight and does not develop a crosslinked structure. Is.

(Gravity sedimentation tank 4)
Next, the gravity settling tank 4 will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the gravity sedimentation tank 4 used in the ashless coal production apparatus 1 shown in FIG. 1, and FIG. 3 is an enlarged view of a main part of FIG. As shown in FIG. 2, the gravity sedimentation tank 4 includes a pressure vessel 11, a supply pipe 12, an outer pipe 13, an exhaust pipe 14, a supernatant liquid discharge pipe 15, and a discharge port 16. A pressure regulating valve 17 is connected.

(Pressure vessel 11)
The pressure vessel 11 is a vessel that separates the slurry from which the solvent-soluble component has been extracted in the extraction tank 3 (see FIG. 1) into a solid concentrate and a supernatant, and has a cylindrical body 11a and a body. A bottom portion 11b connected to the lower end of 11a and having a diameter that decreases toward the bottom. Further, a lid portion 11c for sealing the upper end is provided at the upper end of the body portion 11a. Due to the separation of the slurry, the inside of the pressure vessel 11 is divided into three layers. The three layers are the gas layer 21, the supernatant liquid layer 22, and the solid content concentrated liquid layer 23 from the upper layer. In addition to air, the gas layer 21 contains gases such as methane, carbon dioxide, and water vapor generated by the thermal decomposition reaction of coal. In addition, the bottom part 11b of the pressure vessel 11 may be cylindrical like the trunk | drum 11a. Moreover, the pressure vessel 11 is not limited to a cylindrical shape, and may have another shape.

  In order to prevent reprecipitation of the solvent-soluble component, the pressure vessel 11 is preferably kept warm and pressurized by a heating means, a pressurizing means, etc. (not shown). The heat retention temperature is preferably in the range of 300 to 420 ° C. The pressure is preferably in the range of 1.0 to 3.0 MPa, and more preferably in the range of 1.7 to 2.3 MPa.

(Supernatant liquid discharge pipe 15, discharge port 16)
The supernatant liquid discharge pipe 15 is a pipe for discharging the supernatant liquid from the pressure vessel 11 and penetrates the lid portion 11c (or the body portion 11a). The supernatant liquid is discharged to the outside of the pressure vessel 11 through a supernatant liquid discharge port 15 a provided at the tip of the supernatant liquid discharge pipe 15. On the other hand, the discharge port 16 is a discharge port for discharging the solid concentration liquid settled in the lower part of the pressure vessel 11 from the gravity settling tank 4, and is provided at the lower end of the bottom portion 11b. The discharge port 16 may be a discharge pipe, and the discharge port of the present application includes a discharge pipe.

(Supply pipe 12)
The supply pipe 12 is a pipe for supplying the pressure vessel 11 with the slurry from which the solvent-soluble component has been extracted in the extraction tank 3 (see FIG. 1). The slurry is discharged from a nozzle portion 31 that is formed at the distal end portion of the supply pipe 12 and located inside the pressure vessel 11. Specifically, the tip 32 of the nozzle portion 31 (that is, the tip of the supply pipe 12) opens downward, and the slurry is discharged from the opening 32a. The location where the opening 32 a is provided is not limited to the tip 32, and may be anywhere as long as it is the nozzle portion 31. The supply pipe 12 penetrates the lid portion 11c (may be the trunk portion 11a or the bottom portion 11b), and the tip 32 is located near the middle portion (near the lower side of the trunk portion 11a) in the height direction of the pressure vessel 11. doing. Further, the opening 32 a of the tip 32 is located below the supernatant liquid outlet 15 a of the supernatant liquid outlet pipe 15 and above the outlet upper end 16 a of the outlet 16. The tip 32 may be located in the bottom 11b region, or may be located near the upper side of the body 11a (supernatant liquid layer 22 close to the boundary surface 24). Further, the cross section of the supply pipe 12 is circular, but it may be polygonal. Further, the tip 32 faces downward, but the tip 32 may face upward or may be sideways. Further, the opening 32a of the tip 32 may be located above the supernatant liquid discharge port 15a.

  Here, the nozzle portion 31 refers to a predetermined continuous range including the tip 32 in the supply pipe 12. The “predetermined continuous range” refers to, for example, the outer peripheral surface 12a (see FIG. 3) of the supply pipe 12 and the inner peripheral surface 13a (see FIG. 3) of the outer pipe 13 in the supply pipe 12. Say range. That is, in FIG. 3, the nozzle portion 31 is a range (shaded portion in FIG. 3) from the tip 32 to the upper end 13 b of the outer tube 13 in the supply tube 12. The “predetermined continuous range” varies depending on the positional relationship between the tip 32 and the outer tube 13. For example, when the tip 32 is located below the lower end 13 c of the outer tube 13, the “predetermined continuous range” refers to the outer peripheral surface 12 a of the supply tube 12 and the outer tube 13 of the supply tube 12. A range in which the inner peripheral surface 13a is opposed to each other and a range in which the range from one end of the range (the end on the side close to the tip 32, in this case, the lower end 13c) to the tip 32 are combined.

  The “predetermined continuous range” is not limited to the above-described range. For example, when there is a discharge port (opening) that discharges slurry into the pressure vessel 11 in addition to the tip 32 of the nozzle portion 31, the “predetermined continuous range” is the discharge port (the discharge port) from the tip 32. If there are a plurality of outlets, all of them may be included.

  Moreover, it is preferable that the nozzle part 31 is arrange | positioned at the up-down direction. Here, the “up and down direction” does not simply mean a vertical direction but means a direction inclined with respect to a horizontal plane. In other words, this means that the nozzle portion 31 is arranged along the horizontal plane (in the horizontal direction). When the nozzle portion 31 is arranged along the horizontal plane, the bubbles contained in the slurry are raised along the gap between the outer peripheral surface 31a of the nozzle portion 31 and the inner peripheral surface 13a of the outer tube 13, and the gas layer This is because it may be difficult to achieve the purpose of the present application (see below for details). The “vertical direction” is preferably, for example, ± 45 ° with respect to the vertical direction, and particularly preferably within a range of ± 15 °. This is because the smaller the angle with respect to the vertical direction, the easier the bubbles enter the gap.

(Outer tube 13)
As shown in FIG. 3, the outer tube 13 is formed on the outer periphery of the nozzle portion 31 so as to have a gap between the inner peripheral surface 13 a of the outer tube 13 and the outer peripheral surface 31 a (also simply referred to as a peripheral surface) of the nozzle portion 31. Is provided. The bubbles discharged together with the slurry from the nozzle portion 31 escape from the gap to the gas layer 21 side, thereby preventing the bubbles from diffusing into the pressure vessel 11. That is, by providing the outer tube 13 on the outer periphery of the nozzle portion 31, bubbles contained in the slurry can be extracted toward the gas layer 21 while supplying the slurry to the pressure vessel 11. The outer pipe 13 is supported by a supply pipe 12 (or the pressure vessel 11) by a metal fitting or the like, and is a pipe having a circular cross section with an upper end 13b and a lower end 13c opened. The outer tube 13 is arranged in the vertical direction. The “vertical direction” does not simply mean the vertical direction, like the nozzle portion 31, but means that it is inclined with respect to the horizontal plane. That is, this means that the outer tube 13 is disposed along the horizontal plane (in the horizontal direction). The “vertical direction” is preferably within a range of, for example, ± 45 ° with respect to the vertical direction, and particularly preferably within a range of ± 15 °. This is because the smaller the angle with respect to the vertical direction, the easier the bubbles enter the gap. Further, the outer tube 13 is disposed so as to cross the boundary surface 24 between the gas layer 21 and the supernatant liquid layer 22 (liquid layer), and continuously extends from the lower end 13c to the boundary surface 24 ( That is, from the lower end 13c to the boundary surface 24, there is no air escape port such as a hole on the peripheral surface of the outer tube 13. The upper end 13 b of the outer tube 13 is located in the gas layer 21, and the lower end 13 c of the outer tube 13 is located below the tip 32 of the nozzle part 31. Note that the size of the gap between the inner peripheral surface 13a of the outer tube 13 and the outer peripheral surface 31a of the nozzle portion 31 and the position of the lower end 13c of the outer tube 13 are such that bubbles are diffused into the pressure vessel 11. It is set to an appropriate size from the viewpoint of prevention.

  Here, the lower end 13 c of the outer tube 13 may be above the tip 32 of the nozzle portion 31. Moreover, although the cross section of the outer tube | pipe 13 is a circular tube, other shapes, such as a polygon, may be sufficient. It should be noted that the outer tube 13 has a shape in which the diameter of the outer tube 13 is increased from the intermediate portion toward the lower end 13c so that bubbles contained in the slurry discharged from the nozzle portion 31 can easily enter the gap (that is, the lower portion of the outer tube 13 is The shape of the hem spread).

  In the present embodiment, one supply pipe is provided, but a plurality of supply pipes may be provided. Further, the supply pipe may be branched, for example, in a pressure vessel, and a plurality of nozzle portions may be provided for one supply pipe. When there are a plurality of supply pipes (nozzle parts), it is preferable that the same number of outer pipes are prepared and provided on the outer periphery of each nozzle part.

(Exhaust pipe 14, pressure adjustment valve 17)
The exhaust pipe 14 is a pipe for exhausting the gas in the gas layer 21, is provided so as to penetrate the lid portion 11 c (or the trunk portion 11 a), and is disposed so that the exhaust port is located in the gas layer 21. . Connected to the exhaust pipe 14 is a pressure adjustment valve 17 that mechanically automatically adjusts the pressure in the gas layer 21. The pressure adjusting valve 17 automatically operates when the pressure in the pressure vessel 11 becomes equal to or higher than a specified value, and adjusts the pressure by discharging gas to the outside. And if a pressure falls below a regulation value, it has a function which a valve body closes again. Examples of such valves include spring type and lever type valves. The pressure regulating valve 17 can maintain the pressure in the pressure vessel 11 below a certain value. The adjustment of the pressure regulating valve 17 (open state, locking in the closed state, etc.) may be performed by the user.

(Bubble flow)
Next, the flow of bubbles (gas) such as methane, carbon dioxide, and water vapor generated by the thermal decomposition reaction of coal will be described with reference to FIG. Bubbles generated in the extraction tank 3 (see FIG. 1) and the like flow through the supply pipe 12 together with the slurry from which the solvent-soluble component is extracted, and the pressure vessel 11 (gravity sedimentation tank 4) from the opening 32a of the tip 32 of the nozzle portion 31. ) Is discharged inside. The bubbles rise to the gas layer 21 along the gap between the nozzle portion 31 and the outer tube 13 by buoyancy, and stay in the gas layer 21. Since the bubbles are discharged from the tip 32 of the nozzle part 31, most of the bubbles rise after reaching the lower side of the tip 32 once. Therefore, the outer tube 13 below the distal end 32 of the outer tube 13 serves as a wall, and bubbles that have reached the lower side are prevented from diffusing and flowing to the outside of the outer tube 13. The bubbles staying in the gas layer 21 are discharged from the exhaust pipe 14 to the outside of the pressure vessel 11 by operating the pressure regulating valve 17.

(Modification)
Next, a modification of the gravity settling tank according to the present invention will be described with reference to FIG. The gravity sedimentation tank 4a (first modified example) shown in FIG. 4A is such that the tip portion of the nozzle portion 31 is bent in the horizontal direction and the tip 32 is lateral to the gravity sedimentation tank 4 described above. It is different in point, and is the same in other points. Even if the tip 32 of the nozzle portion 31 is sideways, it is possible to suppress the bubbles from diffusing into the pressure vessel 11 as in the gravity sedimentation tank 4. Further, the gravity settling tank 4b (second modified example) shown in FIG. 4 (b) has a supply pipe 12 penetrating the body 11a of the pressure vessel 11 with respect to the gravity settling tank 4 described above. It differs in that the nozzle portion 31 is formed by being bent through the tube 13 and being bent after the outer tube 13 is being penetrated, and the same in other respects. Even in the case where the supply pipe 12 is provided through the body 11 a (or the bottom 11 b), it is possible to suppress the bubbles from diffusing into the pressure vessel 11 as in the gravity sedimentation tank 4. 4 (a) and 4 (b), the hatched portion in the figure indicates the range of the nozzle portion 31 in each modification. As another modification, for example, a plurality of holes may be formed in a portion of the peripheral surface 31 a of the nozzle portion 31 that faces the inner peripheral surface 13 a of the outer tube 13. Due to the plurality of holes, it is possible to allow air bubbles to escape from the plurality of holes to the gas layer 21.

(Method for producing ashless coal)
Next, a method for producing ashless coal will be described. The method for producing ashless coal according to the present invention includes a slurry preparation step, an extraction step, a separation step, and an ashless coal acquisition step, and further includes a by-product coal acquisition step as necessary.

(Slurry preparation process)
The slurry preparation step is a step of preparing a slurry by mixing coal and a solvent, and is performed in the slurry preparation tank 2.

(Extraction process)
The extraction step is a step of heating the slurry obtained in the slurry preparation step to extract solvent-soluble components, and is performed in the extraction tank 3. The slurry prepared in the slurry preparation tank 2 is supplied to the extraction tank 3 by a pump (not shown), and is heated and held at a predetermined temperature while being stirred by a stirrer 3 a provided in the extraction tank 3 for extraction. Note that the slurry may be supplied to the extraction tank 3 after being supplied to a preheater (not shown) and heated to a predetermined temperature.

  When extracting coal components that are soluble in the solvent by heating the slurry obtained by mixing coal and solvent, a solvent with a large dissolving power for coal, often an aromatic solvent (hydrogen donating property) Or a non-hydrogen-donating solvent) and coal are mixed and heated to extract organic components in the coal.

  There is no restriction | limiting in particular in the coal used as a raw material, Bituminous coal with a high extraction rate (ashless coal recovery rate) may be used, and cheaper inferior quality coal (subbituminous coal, lignite) may be used.

The non-hydrogen donating solvent is a coal derivative which is a solvent mainly composed of a bicyclic aromatic and purified mainly from a coal carbonization product. This non-hydrogen-donating solvent is stable even in a heated state and has excellent affinity with coal. Therefore, the proportion of soluble components (herein, coal components) extracted into the solvent (hereinafter also referred to as extraction rate) In addition, it is a solvent that can be easily recovered by a method such as distillation. Main components of the non-hydrogen donating solvent include bicyclic aromatic naphthalene, methyl naphthalene, dimethyl naphthalene, trimethyl naphthalene and the like, and other non-hydrogen donating solvent components have aliphatic side chains. Naphthalenes, anthracenes, fluorenes, and these include biphenyl and alkylbenzenes having long aliphatic side chains.
In the above description, the case where a non-hydrogen donating compound is used as a solvent has been described, but it is needless to say that a hydrogen donating compound (including coal liquefied oil) typified by tetralin may be used as a solvent. . When a hydrogen donating solvent is used, the yield of ashless coal is improved.

  Moreover, the boiling point of the solvent is not particularly limited, but for example, from the viewpoint of the extraction rate in the extraction step and the solvent recovery rate in the ashless coal acquisition step, a solvent having a boiling point of 180 to 300 ° C, particularly 230 to 280 ° C is preferably used. It is done. Moreover, the density | concentration of the coal raw material with respect to a solvent is although it does not specifically limit, The range of 10-50 weight% is preferable on a dry coal basis, and the range of 15-35 weight% is more preferable.

  The heating temperature of the slurry in the extraction step is not particularly limited as long as the solvent-soluble component can be dissolved. However, from the viewpoint of sufficient extraction of the solvent-soluble component, the heating temperature is, for example, in the range of 300 to 420 ° C. More preferably, it is the range of 350-400 degreeC. The heating time (extraction time) is also not particularly limited, but is preferably in the range of 5 to 60 minutes and more preferably in the range of 20 to 40 minutes from the viewpoint of sufficient dissolution and extraction rate. In addition, the heating time at the time of once heating with a preheater (not shown) is the sum of the heating time in the preheater (not shown) and the heating time in the extraction tank 3.

  The extraction step is preferably performed in the presence of an inert gas, and inexpensive nitrogen is preferably used. 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.

(Separation process)
The separation step is a step of separating the slurry obtained in the extraction step into a solid concentration liquid and a supernatant liquid using any of the gravity sedimentation tanks (4, 4a, 4b) described above. Since any of the gravity settling tanks (4, 4a, 4b) described above is used, turbulence of sedimentation of solids due to gas (bubbles) such as methane, carbon dioxide, and water vapor generated by the thermal decomposition reaction of coal is suppressed. Thus, a supernatant liquid from which the solid content has been sufficiently removed is obtained. The supernatant liquid discharged from the gravity settling tanks (4, 4a, 4b) is filtered by a filter (not shown) installed as necessary, and then discharged to the solvent separator 5. On the other hand, the solid content concentrate is discharged to the solvent separator 6.

(Ashless coal acquisition process)
The ashless coal acquisition step is a step of obtaining ashless coal by evaporating and separating the solvent from the supernatant liquid separated in the separation step, and is performed by the solvent separator 5.

  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 may be discarded, but it can be circulated to the slurry preparation tank 2 and used repeatedly. By separating and collecting the solvent, ashless coal substantially free of ash can be obtained from the solution portion. Ashless coal contains almost no ash, has no moisture, and exhibits a higher calorific value than, for example, raw coal. Furthermore, the softening and melting property, which is a particularly important quality as a raw material for coke for iron making, is greatly improved, and shows far superior performance (fluidity) compared to, for example, raw coal. 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 is a step of obtaining by-product coal by evaporating and separating the solvent from the solid concentrate separated in the separation step, and is performed in the solvent separator 6. . By-product coal is also called residual coal.

(effect)
Next, the effects of the gravity sedimentation tank according to the present invention and the method for producing ashless coal using the same will be described. In the gravity sedimentation tank of the present invention, the nozzle portion 31 formed at the tip end portion of the supply pipe 12 and discharging slurry is disposed inside the pressure vessel 11 so that there is a gap between the nozzle portion 31 and the nozzle portion 31. An outer tube 13 is provided on the outer periphery of the nozzle portion 31. Therefore, the bubbles discharged from the nozzle part 31 together with the slurry rise along the gap between the nozzle part 31 and the outer tube 13. For this reason, the bubbles are prevented from diffusing into the gravity settling tank. Therefore, the solid content in which bubbles have settled in the lower part of the gravity sedimentation tank is not stirred, and the sedimentation of the solid content is prevented from being disturbed without inhibiting the sedimentation of the solid content.

  In addition, the tip 31 of the nozzle portion 31 is open, and the lower end 13 c of the outer tube 13 is positioned below the tip 32. Therefore, the outer tube 13 positioned below the tip 32 serves as a wall, and bubbles contained in the slurry discharged from the tip 32 of the nozzle portion 31 are less likely to diffuse outward than the outer tube 13. As a result, most of the bubbles enter the gap between the nozzle portion 31 and the outer tube 13, and the bubbles can be more effectively suppressed from diffusing into the gravity settling tank.

  Further, the opening 32 a of the tip 32 discharges the supernatant concentrate below the supernatant liquid discharge port 15 a for discharging the supernatant liquid to the outside of the pressure vessel 11 and discharges the solid concentrate to the outside of the pressure vessel 11. It is located above the discharge port 16. Therefore, it is possible to suppress the bubbles contained in the slurry from diffusing into the gravity settling tank while efficiently solid-liquid separating the slurry supplied to the gravity settling tank.

  The outer tube 13 is disposed so as to cross the boundary surface 24 between the gas layer 21 and the supernatant liquid layer 22 (liquid layer), and extends from the lower end 13 c of the outer tube 13 to the boundary surface 24. Yes. Therefore, the bubbles rising along the gap between the nozzle part 31 and the outer tube 13 can be directly released into the gas layer 21. As a result, the bubbles do not diffuse in the supernatant liquid layer 22 or the solid content concentrated liquid layer 23 until the bubbles reach the gas layer 21 from the upper end 13 b of the outer tube 13.

  Further, an exhaust pipe 14 that exhausts gas from the gas layer 21 and a pressure adjustment valve 17 that adjusts the pressure inside the pressure vessel 11 are provided. Therefore, the pressure inside the pressure vessel 11 can be kept below a certain value. As a result, it is possible to prevent the pressure in the gravity sedimentation tank from increasing due to the bubbles discharged from the nozzle portion 31.

  Moreover, the manufacturing method of ashless coal of this invention is a manufacturing method of ashless coal using an above described gravity sedimentation tank. Therefore, the diffusion of bubbles into the tank is suppressed, and the sedimentation efficiency is excellent. Therefore, ashless coal with reduced ash content can be produced efficiently and inexpensively.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. is there.

  For example, the slurry preparation tank 2 may be eliminated, and the slurry preparation process may be performed in a pipe for supplying the slurry to the extraction tank 3. For example, the coal may be supplied into the pipe using a pressure supply means such as a lock hopper. It is also possible to prepare slurry in the extraction tank 3 by directly connecting a pressure supply means such as a lock hopper to the extraction tank 3.

  Further, the extraction tank 3 may be eliminated in addition to the slurry preparation tank 2, and the slurry preparation process and the extraction process may be performed in the supply pipe 12 or the gravity settling tank 4. For example, coal may be supplied into the supply pipe 12 using a pressure supply means such as a lock hopper.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of ashless coal 2 Slurry preparation tank 3 Extraction tank 4, 4a, 4b Gravity sedimentation tank 5, 6 Solvent separator 11 Pressure vessel 12 Supply pipe 13 Outer pipe 13a Inner peripheral surface 13b Upper end 13c Lower end 14 Exhaust pipe 15 Supernatant Liquid discharge pipe 15a Supernatant liquid outlet 16 Outlet 17 Pressure regulating valve 21 Gas layer 22 Supernatant liquid layer (liquid layer)
24 Boundary surface 31 Nozzle part 31a Outer peripheral surface (peripheral surface)
32 Tip 32a Opening

Claims (5)

A pressure vessel that settles solids contained in a slurry formed by mixing and heating coal and a solvent and separates them into a solid concentrate and a supernatant;
A supply pipe for supplying the slurry to the pressure vessel,
A nozzle part that is formed at a tip part of the supply pipe and discharges the slurry is disposed inside the pressure vessel,
An outer tube is provided on the outer periphery of the nozzle part so as to have a gap with the nozzle part,
The nozzle portion, the tip is open, is disposed within a range of ± 45 ° with respect to lead straight direction,
A gravity sedimentation tank, wherein a lower end of the outer tube is located below the tip and above a boundary between the solid concentrate layer and the supernatant layer . A supernatant discharge pipe for discharging the supernatant to the outside of the pressure vessel;
A discharge port for discharging the solid content concentrate to the outside of the pressure vessel;
The gravity settling tank according to claim 1, wherein the opening at the tip is located below the supernatant liquid outlet of the supernatant liquid discharge pipe and above the outlet.   The outer tube is disposed so as to cross a boundary surface between the upper gas layer in the pressure vessel and the liquid layer containing the supernatant liquid, and extends from the lower end of the outer tube to the boundary surface. The gravity sedimentation tank according to claim 1, wherein the gravity sedimentation tank is provided. An exhaust pipe attached to the pressure vessel and exhausting gas from an upper gas layer in the pressure vessel;
The gravity settling tank according to any one of claims 1 to 3, further comprising a pressure regulating valve connected to the exhaust pipe and regulating a pressure in the pressure vessel. A slurry preparation step of preparing a slurry by mixing coal and a solvent;
An extraction step of extracting the coal component soluble in the solvent by heating the slurry prepared in the slurry preparation step;
A separation step in which the slurry from which the coal component has been extracted in the extraction step is separated into a solid content concentrate and a supernatant by the gravity settling tank according to any one of claims 1 to 4.
A method for producing ashless coal, comprising: an ashless coal obtaining step of obtaining ashless coal by evaporating and separating a solvent from the supernatant liquid separated in the separation step.

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