Abstract:
To provide a pyrolyzed coal finisher capable of deactivating pyrolyzed coal within a short time without causing a cost increase. A pyrolyzed coal finisher includes: a mixer  86  that forms slurry by mixing particulate pyrolyzed coal that is pyrolyzed coal into a chemical solution having an oxygen blocking function after being solidified; and a belt filter device  88  that filters the slurry formed in the mixer  86  in a state in which each particle of the pyrolyzed coal is coated with the chemical solution. The pyrolyzed coal finisher further includes a chemical solution circulation path  94  that guides the chemical solution separated from the pyrolyzed coal by the belt filter device  88  to the mixer  86.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a pyrolyzed coal finisher which deactivates pyrolyzed coal so as to avoid spontaneous combustion, a coal upgrade plant, and a method for manufacturing deactivated pyrolyzed coal. 
         [0003]    2. Description of Related Art 
         [0004]    Since low ranking coal such as sub-bituminous coal and lignite has a lower carbonization degree and a higher water content than high ranking coal, a calorific value per unit weight is lower. However, since there are abundant deposits of low ranking coal, the low ranking coal is desired to be effectively used. Thus, various coal upgrading techniques have been studied in which the calorific value of the low ranking coal is increased by performing pyrolysis after drying the low ranking coal, and upgraded coal is deactivated so as to prevent spontaneous combustion during transportation or storage (e.g., Japanese Unexamined Patent Application, Publication No. 2014-31462 (hereinafter referred to as JPA 2014-31462) and PCT International Publication No. WO 2013/103097 (hereinafter referred to as WO 2013/103097)). 
         [0005]    JPA 2014-31462 and WO 2013/103097 disclose that pyrolyzed coal after pyrolysis is cooled, and oxygen is then brought into contact with the pyrolyzed coal to oxidize the pyrolyzed coal and thereby deactivate the surface of the pyrolyzed coal. 
         [0006]    However, it is necessary to gradually perform the oxidation by slowing down an oxidation rate in order to avoid the spontaneous combustion of the pyrolyzed coal caused by rapid oxidation. Thus, it takes an enormous amount of time to perform the deactivating process. 
         [0007]    Each of JPA 2014-31462 and WO 2013/103097 also discloses that particles of the pyrolyzed coal are gathered and molded (briquetted) into a predetermined shape so as to reduce the surface area, and the deactivating process is performed. 
         [0008]    However, a briquetter for briquetting the pyrolyzed coal is required, which is one of the causes for a cost increase. 
         [0009]    The present invention has been made in view of such circumstances, and an object thereof is to provide a pyrolyzed coal finisher, a coal upgrade plant, and a method for manufacturing deactivated pyrolyzed coal capable of deactivating pyrolyzed coal within a short time without causing a cost increase. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    To achieve the above object, a pyrolyzed coal finisher, a coal upgrade plant, and a method for manufacturing deactivated pyrolyzed coal of the present invention employ the following solutions. 
         [0011]    A pyrolyzed coal finisher according to one aspect of the present invention includes: a mixer that forms slurry by mixing particulate pyrolyzed coal that is pyrolyzed coal into a chemical solution having an oxygen blocking function after being solidified; and a filter that filters the slurry formed in the mixer in a state in which each particle of the pyrolyzed coal is coated with the chemical solution. 
         [0012]    By forming the slurry of the chemical solution having the oxygen blocking function after being solidified and the particulate pyrolyzed coal, and filtering the slurry by the filter to coat each particle of the pyrolyzed coal with the chemical solution, deactivated pyrolyzed coal, each particle of which is entirely coated with an oxygen blocking film, can be obtained. As described above, by filtering the slurry by the filter, the deactivated pyrolyzed coal evenly coated with the oxygen blocking film can be mass-manufactured. 
         [0013]    The deactivation of the pyrolyzed coal can be achieved by coating the pyrolyzed coal with the chemical solution having the oxygen blocking function. Thus, a deactivating equipment that oxidizes the pyrolyzed coal gradually from the surface over time by bringing the pyrolyzed coal into contact with oxygen or air as in conventional cases is not required, so that the length of time required for treatment and the costs can be reduced. 
         [0014]    Since each particle of the pyrolyzed coal can be deactivated, a briquetter that gathers the particulate pyrolyzed coal and molds (briquettes) the pyrolyzed coal so as to reduce the surface area is not required. Thus, the length of time required for treatment and the costs can be reduced. Since the entire surface of each particle is coated with the oxygen blocking film, the deactivation can be more surely achieved than using a deactivating method of briquetting the particulate pyrolyzed coal so as to reduce the surface area. 
         [0015]    A chemical solution obtained by dissolving a polymer such as polyethylene oxide and starch in a solvent such as water is used as the chemical solution having the oxygen blocking function after being solidified. It is preferable to use a chemical solution that is solidified at a normal temperature. 
         [0016]    For example, the particles of the pyrolyzed coal have a particle size of about 0.5 to 5.0 mm. 
         [0017]    The pyrolyzed coal finisher according to one aspect of the present invention further includes a chemical solution circulation path that guides the chemical solution separated from the pyrolyzed coal by the filter to the mixer. 
         [0018]    Since the chemical solution separated from the pyrolyzed coal by the filter is returned to the mixer to be reused, the used amount of the chemical solution can be reduced. 
         [0019]    In the pyrolyzed coal finisher according to one aspect of the present invention, the filter is a belt filter. 
         [0020]    Since the belt filter is used as the filter, continuous treatment is enabled, so that the deactivated pyrolyzed coal can be mass-manufactured. 
         [0021]    A coal upgrade plant according to one aspect of the present invention includes: a pyrolyzer that pyrolyzes coal; and the above pyrolyzed coal finisher that deactivates the pyrolyzed coal pyrolyzed by the pyrolyzer. 
         [0022]    Since the above pyrolyzed coal finisher is used, deactivated pyrolyzed coal evenly coated with an oxygen blocking film can be obtained. 
         [0023]    A method for manufacturing deactivated pyrolyzed coal according to one aspect of the present invention includes: a mixing step of forming slurry by mixing particles of pyrolyzed coal that is pyrolyzed coal into a chemical solution having an oxygen blocking function after being solidified; and a filtering step of filtering the slurry formed in the mixing step in a state in which each particle of the pyrolyzed coal is coated with the chemical solution. 
         [0024]    By forming the slurry of the chemical solution having the oxygen blocking function after being solidified and the particles of the pyrolyzed coal, and filtering the slurry by the filter to coat each particle of the pyrolyzed coal with the chemical solution, deactivated pyrolyzed coal, each particle of which is entirely coated with an oxygen blocking film, can be obtained. As described above, by filtering the slurry by the filter, the deactivated pyrolyzed coal evenly coated with the oxygen blocking film can be mass-manufactured. 
         [0025]    Since the pyrolyzed coal is deactivated by filtering the slurry of the pyrolyzed coal and the chemical solution having the oxygen blocking function by the filter, the pyrolyzed coal can be deactivated within a short time. 
         [0026]    Also, since the deactivation is enabled without using a finisher using oxidation, and a briquetter as in conventional cases, the costs can be reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0027]      FIG. 1  is a schematic configuration diagram illustrating the entire configuration of a coal upgrade plant according to one embodiment of the present invention. 
           [0028]      FIG. 2  is a schematic configuration diagram illustrating a finisher shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    In the following, one embodiment according to the present invention is described by reference to the drawings. 
         [0030]      FIG. 1  shows a coal upgrade plant including a pyrolyzed coal finisher according to one embodiment of the present invention. The coal upgrade plant includes a dryer  1  that heats and dries coal, a pyrolyzer  3  that heats and pyrolyzes the dried coal dried in the dryer  1 , a quencher  5  that cools the pyrolyzed coal pyrolyzed in the pyrolyzer  3 , and a pyrolyzed coal finisher (simply referred to as “finisher” below)  7  that deactivates the pyrolyzed coal cooled in the quencher  5 . 
         [0031]    A coal hopper  12  that receives raw coal  10  is provided on the upstream side of the dryer  1 . The raw coal is low ranking coal such as sub-bituminous coal and lignite, and has a water content of 25 wt % or more to 60 wt % or less. The coal guided from the coal hopper  12  is crushed to a particle size of, for example, about 20 mm or less in a crusher  14 . 
         [0032]    The coal crushed in the crusher  14  is guided to the dryer  1 . The dryer  1  is of indirect heating type using steam, and includes a cylindrical vessel  16  that rotates about a center axis, and a plurality of heating tubes  18  that are inserted into the cylindrical vessel  16 . The coal guided from the crusher  14  is fed into the cylindrical vessel  16 . The coal fed into the cylindrical vessel  16  is guided from one end side (the left side in  FIG. 1 ) to the other end side while being agitated according to the rotation of the cylindrical vessel  16 . Steam having a temperature of 150° C. or more to 200° C. or less (more specifically, 180° C.), which is produced in a steam system  20 , is fed into each of the heating tubes  18 , thereby indirectly heating the coal in contact with the outer periphery of each of the heating tubes  18 . The steam fed into each of the heating tubes  18  is condensed after applying condensation heat by heating the coal, discharged from the dryer  1 , and returned to the steam system  20 . 
         [0033]    A carrier gas is fed into the cylindrical vessel  16  through a carrier gas circulation path  22 . As the carrier gas, an inert gas is used. More specifically, a nitrogen gas is used. When in shortage, the nitrogen gas is additionally fed from a nitrogen feed path  24  that is connected to the carrier gas circulation path  22 . The carrier gas is discharged outside of the cylindrical vessel  16  through a carrier gas discharge path  26  that is connected to the cylindrical vessel  16  while catching a desorbed component (steam, pulverized coal, mercury, mercury-based substances, etc.) desorbed from the coal when passing through the cylindrical vessel  16 . 
         [0034]    A cyclone (dust collector)  28 , a carrier gas cooler  30 , and a scrubber  32  are provided in the carrier gas discharge path  26  sequentially from the upstream side of a carrier gas flow direction. 
         [0035]    The cyclone  28  mainly removes the pulverized coal (for example, having a particle size of 100 μm or less) that is a solid from the carrier gas by use of a centrifugal force. The pulverized coal removed in the cyclone  28  is guided to the upstream side of a bag filter  34  as indicated by reference character A. The pulverized coal separated in the cyclone  28  may be also mixed into the dried coal dried in the dryer  1 . 
         [0036]    The carrier gas cooler  30  cools the carrier gas, from which the pulverized coal has been removed, thereby condensing steam guided together with the carrier gas and removing the condensed steam as drain water. The carrier gas cooler  30  is an indirect heat exchanger. Industrial water having a normal temperature is used as a cooling medium. Recycled water separated in a waste water treatment equipment  40  may be also used as the cooling medium. The drain water produced in the carrier gas cooler  30  is guided to a liquid phase section in a lower portion of the scrubber  32 . 
         [0037]    The scrubber  32  removes the mercury and/or the mercury-based substances (simply referred to as “mercury etc.” below) from the carrier gas, from which the pulverized coal and the steam have been removed. Water is used as an absorber used in the scrubber  32 . More specifically, the recycled water separated in the waste water treatment equipment  40  is used. The mercury etc. in the carrier gas is adsorbed by the water sprayed from above the scrubber  32 , and guided to the liquid phase section in the lower portion of the scrubber  32 . In the scrubber  32 , the pulverized coal that could not be removed in the cyclone  28  is also removed. 
         [0038]    An upstream end of the carrier gas circulation path  22  is connected to an upper portion of the scrubber  32 . A blower  36  is provided at an intermediate position of the carrier gas circulation path  22 . The carrier gas treated in the scrubber  32  is returned to the dryer  1  by the blower  36 . Although not shown in the drawings, one portion of the carrier gas treated in the scrubber  32  is guided to a combustor  42 . 
         [0039]    The waste water treatment equipment  40  is connected to the lower portion of the scrubber  32  through a waste water path  38 . The waste water treatment equipment  40  separates sludge  39 , which is a solid content such as the pulverized coal and the mercury etc., and the recycled water by a sedimentation tank (not shown) after aggregating and enlarging the mercury etc. by injecting a chelating agent into waste water. The recycled water is reused in various portions of the plant. 
         [0040]    The coal (dried coal) dried in the dryer  1  passes through a dried coal feed path  44  to be guided to the pyrolyzer  3  by use of its weight. The pyrolyzer  3  is an external-heat rotary kiln, and includes a rotating inner cylinder  46 , and an outer cylinder  48  that covers the outer peripheral side of the rotating inner cylinder  46 . A nitrogen gas as a carrier gas is fed into the rotating inner cylinder  46 . 
         [0041]    A combustion gas produced in the combustor  42  is guided to a space between the rotating inner cylinder  46  and the outer cylinder  48  through a combustion gas introduction path  50 . Accordingly, the inside of the rotating inner cylinder  46  is maintained at 350° C. or more to 450° C. or less (for example, 400° C.) 
         [0042]    To the combustor  42 , an air feed path  54  that guides combustion air force-fed by a blower  52  into the combustor, a natural gas feed path  55  that guides a natural gas as fuel into the combustor, and a pyrolysis gas collection path  56  that collects a pyrolysis gas generated in the pyrolyzer  3  together with the carrier gas, and guides the gas into the combustor are connected. In the combustor  42 , a fire  51  is formed by the natural gas, the pyrolysis gas, and the air fed into the combustor. Since the pyrolysis gas contains a volatile content such as tar and has a predetermined calorific value, the pyrolysis gas is used as fuel in the combustor  42 . The natural gas fed from the natural gas feed path  55  is used for adjusting a calorific value of the fuel injected into the combustor  42 . A flow rate of the natural gas is adjusted such that the combustion gas produced in the combustor  42  has a desired temperature. 
         [0043]    A pyrolysis gas discharge path  58  that is used in emergency is connected to an intermediate position of the pyrolysis gas collection path  56 . A flare stack  60  is installed on the downstream side of the pyrolysis gas discharge path  58 . A combustible component such as tar in the pyrolysis gas is incinerated by the flare stack  60 , and a gas obtained after the incineration is released to the atmosphere. 
         [0044]    A combustion gas discharge path  62  through which the combustion gas produced in the combustor is discharged is connected to the combustor  42 . An upstream end of the combustion gas introduction path  50  that guides the combustion gas to the pyrolyzer  3  is connected to an intermediate position of the combustion gas discharge path  62 . A first medium-pressure boiler  64  is provided in the combustion gas discharge path  62  on the downstream side of a connection position with the combustion gas introduction path  50 . 
         [0045]    An after-heating gas discharge path  66  through which the combustion gas after heating the rotating inner cylinder  46  is discharged is connected to the outer cylinder  48  of the pyrolyzer  3 . A second medium-pressure boiler  68  is provided in the after-heating gas discharge path  66 . The after-heating gas discharge path  66  is connected to the combustion gas discharge path  62  on the downstream side. A blower  70  that force-feeds the combustion gas is provided in the combustion gas discharge path  62  on the downstream side of a connection position with the after-heating gas discharge path  66 . 
         [0046]    The downstream side of the combustion gas discharge path  62  is connected to the bag filter  34 . A flue gas, from which combustion ash or the like is removed in the bag filter  34 , is released to the atmosphere (ATM). 
         [0047]    The steam system  20  includes the first medium-pressure boiler  64  and the second medium-pressure boiler  68 . In the second medium-pressure boiler  68 , boiler feed water (BFW) fed thereto is heated by the combustion gas flowing through the after-heating gas discharge path  66 , thereby producing steam. In the first medium-pressure boiler  64 , the steam produced in the second medium-pressure boiler  68  is guided, and heated by the flue gas flowing through the combustion gas discharge path  62 , thereby producing steam having a higher pressure. Medium-pressure steam produced in the first medium-pressure boiler  64  and medium-pressure steam produced in the second medium-pressure boiler  68  are respectively stored in a steam drum (not shown), and fed to various portions of the plant such as the heating tubes  18  of the dryer  1 . 
         [0048]    The pyrolyzed coal pyrolyzed in the pyrolyzer  3  is guided to the quencher  5  through a pyrolyzed coal feed path  72  by use of gravity. The quencher  5  includes a first cooler  74  that receives the pyrolyzed coal from the pyrolyzer  3 , and a second cooler  76  that receives the pyrolyzed coal cooled by the first cooler  74 . 
         [0049]    The first cooler  74  is a shell-and-tube heat exchanger, and includes a first cylindrical vessel  78  that rotates about a center axis, a first water spray tube  79  that is inserted into the first cylindrical vessel  78 , and a plurality of first cooling tubes  80  that are inserted into the first cylindrical vessel  78 . The first water spray tube  79  is installed in a stationary state with respect to the rotating first cylindrical vessel  78 . The pyrolyzed coal having a temperature of 300° C. or more to 500° C. or less (for example, about 400° C.), which is guided from the pyrolyzer  3 , is fed into the first cylindrical vessel  78 . The pyrolyzed coal fed into the first cylindrical vessel  78  is guided from one end side (the left side in  FIG. 1 ) to the other end side while being agitated according to the rotation of the first cylindrical vessel  78 . 
         [0050]    Industrial water having a normal temperature is guided to the first water spray tube  79 . The water is sprayed on the pyrolyzed coal and thereby brought into direct contact with the pyrolyzed coal to cool down the pyrolyzed coal. The first water spray tube  79  is provided on the upstream side (the left side in  FIG. 1 ) of the pyrolyzed coal moving within the first cylindrical vessel  78 . The recycled water separated in the waste water treatment equipment  40  may be used as the water fed to the first water spray tube  79 . 
         [0051]    Boiler feed water having a temperature of 50° C. or more to 100° C. or less (for example, about 60° C.) is fed into each of the first cooling tubes  80 , thereby indirectly cooling the pyrolyzed coal in contact with the outer periphery of each of the first cooling tubes  80 . Each of the first cooling tubes  80  is provided on the downstream side (the right side in  FIG. 1 ) of the pyrolyzed coal moving within the first cylindrical vessel  78 . Each of the first cooling tubes  80  cools the pyrolyzed coal cooled by the first water spray tube  79  to about 150° C. that is equal to or higher than a condensation temperature of water. 
         [0052]    The second cooler  76  has substantially the same configuration as the first cooler  74 . The second cooler  76  is a shell-and-tube heat exchanger, and includes a second cylindrical vessel  81  that rotates about a center axis, a second water spray tube  82  that is inserted into the second cylindrical vessel  81 , and a plurality of second cooling tubes  83  that are inserted into the second cylindrical vessel  81 . The second water spray tube  82  is installed in a stationary state with respect to the rotating second cylindrical vessel  81 . The pyrolyzed coal cooled to about 150° C. in the first cooler  74  is fed into the second cylindrical vessel  81 . The pyrolyzed coal fed into the second cylindrical vessel  81  is guided from one end side (the left side in  FIG. 1 ) to the other end side while being agitated according to the rotation of the second cylindrical vessel  81 . 
         [0053]    Industrial water having a normal temperature is guided to the second water spray tube  82 . The water is sprayed on the pyrolyzed coal to adjust the water content of the pyrolyzed coal to a desired value (for example, 8 wt %). The second water spray tube  82  is provided over substantially the entire second cylindrical vessel  81  in an axial direction. The recycled water separated in the waste water treatment equipment  40  may be used as the water fed to the second water spray tube  82 . 
         [0054]    Industrial water having a normal temperature is guided into each of the second cooling tubes  83 , thereby indirectly cooling the pyrolyzed coal in contact with the outer periphery of each of the second cooling tubes  83 . Each of the second cooling tubes  83  cools the pyrolyzed coal to about 50° C. The recycled water separated in the waste water treatment equipment  40  may be used as the water fed to each of the second cooling tubes  83 . 
         [0055]    The pyrolyzed coal cooled in the quencher  5  is guided to the finisher  7  through a cooled pyrolyzed coal feed path  84 . 
         [0056]    As shown in  FIG. 2 , the finisher  7  includes a mixer  86  and a belt filter device  88 . 
         [0057]    The pyrolyzed coal guided from the quencher  5 , and a chemical solution for performing a deactivating process are guided to the mixer  86 . The mixer  86  mixes the pyrolyzed coal and the chemical solution by a kneader (not shown) to form slurry of the pyrolyzed coal and the chemical solution. 
         [0058]    The pyrolyzed coal guided to the mixer  86  has a particulate form, and has a particle size of about 0.5 to 5.0 mm. 
         [0059]    The chemical solution has an oxygen blocking function after being solidified. For example, a chemical solution obtained by dissolving a polymer such as polyethylene oxide and starch in a solvent such as water is used. It is preferable to use a chemical solution, such as polyethylene oxide and starch, which is solidified at a normal temperature. 
         [0060]    The belt filter device  88  includes an endless belt filter  90  where a mesh-like filter section is formed over substantially the entire belt surface, and a pair of rollers  92  where the belt filter  90  is wound. The belt filter  90  has a mesh small enough not to pass the particulate pyrolyzed coal having a particle size of, for example, about 1 mm. A drive device (not shown) is provided in the rollers  92 . The rollers  92  are rotated about axes as indicated by arrows in the drawing by the power of the drive device. 
         [0061]    Although not shown in the drawings, a press that presses the belt filter  90  from above or a suction device that sucks the belt filter  90  from below while the belt filter  90  is running substantially in a horizontal direction between upper ends of the rollers  92  is provided. The slurry fed from the mixer  86  to one upper end (the left side in the drawing) of the belt filter  90  through a slurry feed path  87  is filtered by the press or the suction device described above while being transferred to the other end side along with the belt filter  90  running substantially in the horizontal direction. Accordingly, the slurry is separated into the particulate pyrolyzed coal coated with the chemical solution over the entire surface, and the chemical solution after passing through the belt filter  90 . 
         [0062]    The coated particulate pyrolyzed coal separated by the belt filter  90  is removed from the belt filter  90  by a scraper or the like (not shown). The chemical solution is solidified at a normal temperature, so that an oxygen blocking film is formed over the entire surface of each particle. Deactivated pyrolyzed coal, i.e., final upgraded coal  104  is thereby obtained. 
         [0063]    The chemical solution separated by the belt filter  90  is collected from a lower portion, and transferred to the mixer  86  again through a chemical solution circulation path  94 . 
         [0064]    The following effects are produced by the present embodiment. 
         [0065]    By forming the slurry of the chemical solution having the oxygen blocking function after being solidified and the particulate pyrolyzed coal, and filtering the slurry by the belt filter  90  to coat each particle of the particulate pyrolyzed coal with the chemical solution, the deactivated pyrolyzed coal, each particle of which is entirely coated with the oxygen blocking film, can be obtained. As described above, by filtering the slurry by the belt filter  90 , the deactivated pyrolyzed coal evenly coated with the oxygen blocking film can be mass-manufactured. 
         [0066]    Also, the deactivation of the pyrolyzed coal can be achieved by coating the pyrolyzed coal with the chemical solution having the oxygen blocking function. Thus, a deactivating equipment that oxidizes the pyrolyzed coal gradually from the surface over time by bringing the pyrolyzed coal into contact with oxygen or air as in conventional cases is not required, so that the length of time required for treatment and the costs can be reduced. 
         [0067]    Since each particle of the particulate pyrolyzed coal can be deactivated, a briquetter that gathers the particulate pyrolyzed coal and molds (briquettes) the pyrolyzed coal so as to reduce the surface area is not required. Thus, the length of time required for treatment and the costs can be reduced. Since the entire surface of each particle is coated with the oxygen blocking film, the deactivation can be more surely achieved than using a deactivating method of briquetting the particulate pyrolyzed coal so as to reduce the surface area. 
         [0068]    Since the chemical solution separated from the pyrolyzed coal by the belt filter device  88  is returned to the mixer  86  through the chemical solution circulation path  94  to be reused, the used amount of the chemical solution can be reduced. 
         [0069]    Since the belt filter  90  is used, continuous treatment is enabled, so that the deactivated pyrolyzed coal can be mass-manufactured.
     1  Dryer     3  Pyrolyzer     5  Quencher     7  Finisher     9  Briquetter     10  Raw coal     12  Coal hopper     14  Crusher     16  Cylindrical vessel     18  Heating tube     20  Steam system     22  Carrier gas circulation path     28  Cyclone     30  Carrier gas cooler     32  Scrubber     34  Bag filter     40  Waste water treatment equipment     42  Combustor     46  Rotating inner cylinder     48  Outer cylinder     50  Combustion gas introduction path     74  First cooler     76  Second cooler     78  First cylindrical vessel     79  First water spray tube     80  First cooling tube     81  Second cylindrical vessel     82  Second water spray tube     83  Second cooling tube     86  Mixer     87  Slurry feed path     88  Belt filter device     90  Belt filter     92  Roller     94  Chemical solution circulation path     104  Upgraded coal