Subcritical water treatment apparatus and subcritical water treatment unit

Abstract

To provide a subcritical water treatment apparatus and a subcritical water treatment unit that are capable of performing subcritical water treatment while moving organic wastes at an appropriate speed along a centerline of a stirring mechanism, thereby improving the treatment efficiency of the organic wastes.SOLUTION: One aspect of the present invention provides a subcritical water treatment apparatus for subjecting organic wastes to subcritical water treatment to obtain a treated product. The subcritical water treatment apparatus has a pressure vessel having a centerline along a horizontal direction, a stirring mechanism to stir the organic wastes contained in the pressure vessel, and a heating mechanism to heat the organic wastes. The pressure vessel comprises a vessel body, an inlet for introducing the organic wastes into the vessel body, and an outlet for discharging the treated product from the vessel body. The stirring mechanism comprises a rotating shaft arranged along the centerline, and a plurality of spaced stirring blades protruding radially outward from the rotating shaft along an intersection line that is substantially orthogonal to the centerline. Each stirring blade comprises a flat surface that is substantially parallel to the intersection line and inclined relative to the centerline.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a subcritical water treatment apparatus and a subcritical water treatment unit.

Background Art

[0002] Patent Document 1 describes an organic waste treatment apparatus that performs treatment such as decomposition of waste using a hydrothermal reaction under subcritical water conditions. This organic waste treatment apparatus has a heat-resistant and pressure-resistant container and a screw blade provided inside the heat-resistant and pressure-resistant container. Then, the waste accommodated in the heat-resistant and pressure-resistant container is treated while being stirred by the screw blade.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when stirring waste with a screw blade as described in Patent Document 1, the waste moves largely to one side along the axis (center line) of the screw blade and becomes unevenly distributed inside the heat-resistant and pressure-resistant container. Therefore, in such an organic waste treatment apparatus, it is necessary to frequently repeat the forward and reverse rotations of the screw blade in order to sufficiently perform treatment such as decomposition on the waste.

[0005] In view of the above circumstances, the present invention provides a subcritical water treatment apparatus and a subcritical water treatment unit capable of performing subcritical water treatment while moving organic waste along the center line of the stirring mechanism at an appropriate speed, and improving the treatment efficiency of organic waste.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a subcritical water treatment apparatus is provided that subjects organic waste to subcritical water treatment to obtain a treated product. This subcritical water treatment apparatus includes a pressure vessel having a center line along the horizontal direction, a stirring mechanism for stirring the organic waste housed in the pressure vessel, and a heating mechanism for heating the organic waste. The pressure vessel includes a vessel body, an inlet for introducing the organic waste into the vessel body, and an outlet for discharging the treated product from the vessel body. The stirring mechanism includes a rotating shaft disposed along the center line, and a plurality of stirring blades that project radially outward from the rotating shaft along an intersection line that is substantially orthogonal to the center line and are provided spaced apart from each other. Each stirring blade includes a flat surface that is substantially parallel along the intersection line and inclined with respect to the center line.

[0007] According to such an aspect, subcritical water treatment can be performed while moving the organic waste along the center line of the stirring mechanism at an appropriate speed, and as a result, the treatment efficiency of the organic waste can be improved.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic matters shown in the embodiments described below can be combined with each other. <Subcritical Water Treatment Apparatus> First, the subcritical water treatment apparatus of the present invention will be described.

[0010] FIG. 1 is a conceptual diagram showing an embodiment of a subcritical water treatment apparatus in a partial cross section. FIG. 2 is a plan view showing the configuration of a partition plate. The subcritical water treatment apparatus 1 of the present invention is a subcritical water treatment apparatus that subjects organic waste to subcritical water treatment to obtain a treated product. Here, subcritical water treatment is a method in which gaseous subcritical water is brought into contact with organic waste under high temperature and high pressure, where the temperature is below the critical temperature of water and the pressure is above the saturated vapor pressure, to reduce the molecular weight. Through this reduction in molecular weight, the organic waste is decomposed to obtain treated products.

[0011] Organic waste is usually waste that cannot be hydrolyzed by anaerobic bacteria or aerobic bacteria. Examples of such organic waste include papers, cloths, clothes, plastics, rubbers, leathers, woods and bamboos, straws, kitchen waste, non-combustibles, medical waste, packaged waste foods, etc., and may include one or more of these. The subcritical water treatment apparatus 1 shown in Fig. 1 includes a pressure vessel 2 having a center line O21 along the horizontal direction, a stirring mechanism 3 for stirring the organic waste accommodated in the pressure vessel 2, and a heating mechanism 4 for heating the organic waste. In the following description, the circumferential direction means the direction around the center line O21, and the radial direction means the direction of the radius centered on the center line O21.

[0012] The pressure vessel 2 includes a vessel body 21, an inlet 22 for introducing organic waste into the vessel body 21, an outlet 23 for discharging the treated product from the vessel body 21, a liquid storage part 24, a partition plate 25, and a pedestal 29. The pressure vessel 2 of the present embodiment is a horizontally placed pressure vessel supported by a pedestal 29 such that the center line O21 of the vessel body 21 is along the horizontal direction.

[0013] The volume of the vessel body 21 is preferably about 200 to 5000 L, more preferably about 250 to 4000 L, and even more preferably about 300 to 3000 L. By using the vessel body 21 with such a volume, while sufficiently accommodating the organic waste, the subcritical water treatment apparatus 1 can be sufficiently miniaturized, meeting the needs for a large-capacity and space-saving subcritical water treatment apparatus 1. Also, as will be described later, the subcritical water treatment apparatus 1 can be accommodated in a container, and in this state, it can be transported to the desired location.

[0014] The inlet 22 has a cylindrical body portion 221 and is connected to the container body 21 so as to communicate with a through hole 2113 formed in the upper portion of the container body 21. Further, the inlet 22 has a lid portion (clutch door) 223 that airtightly seals the opening 222 of the body portion 221. Furthermore, the inlet 22 has pressure vessel valves 224 and 225. By opening and closing the pressure vessel valve 224 or 225, the pressure inside the pressure vessel 2 can be adjusted. Note that the pressure vessel valve 224 or 225 does not necessarily have to be provided at the inlet 22 and may be provided at other locations of the pressure vessel 2.

[0015] The discharge port 23 has a cylindrical body portion 231 and is connected to the container body 21 so as to communicate with a through hole 2123 formed at the end of the container body 21. Therefore, the center line O23 of the discharge port 23 (body portion 231) is inclined with respect to the center line O21 of the container body 21, and the opening 232 on the side opposite to the container body 21 faces obliquely downward in the vertical direction. Further, the discharge port 23 has a lid portion (clutch door) 233 that airtightly seals the opening 232 of the body portion 231.

[0016] In such a pressure vessel 2, by opening the lid portion 223 with the lid portion 233 closed, organic waste can be introduced into the container body 21 through the body portion 221 of the inlet 22. Thereafter, with the lid portion 223 closed, subcritical water treatment is performed on the organic waste in the container body 21. The treated product generated by the subcritical water treatment of the organic waste can be taken out from the container body 21 through the body portion 231 of the discharge port 23 by opening the lid portion 233. In particular, since the center line O23 of the discharge port 23 is inclined with respect to the center line O21 of the container body 21, it is easy to perform the discharge (removal) operation of the treated product from the container body 21.

[0017] The liquid storage section 24 is provided in the pressure vessel 2 and stores the liquid L used for the subcritical water treatment of organic waste. With the liquid L stored in the liquid storage section 24, the pressure vessel 2 is sealed, and the heating mechanism 4 starts heating the organic waste. As a result, gaseous subcritical water is generated from the liquid L stored in the liquid storage section 24, and by bringing this subcritical water into contact with the organic waste, the low-molecularization of the organic waste proceeds. Here, the above liquid L may mainly contain water and may contain other components. Examples of other components include hydrogen peroxide, sodium hydroxide, and the like.

[0018] According to such a subcritical water treatment apparatus 1, since it does not have an attached high-pressure boiler, the subcritical water treatment apparatus 1 can be downsized. Therefore, the subcritical water treatment apparatus 1 can be installed in a relatively narrow space. For this reason, as will be described later, if the subcritical water treatment apparatus 1 is configured to be movable and arranged adjacent to a convenience store in an urban area, it is possible to easily perform subcritical water treatment on perishable daily items (mainly bento boxes, etc.) that are discarded. Also, since it does not have an attached high-pressure boiler, the operation and operation of the subcritical water treatment apparatus 1 can be performed not only by a qualified boiler technician but also by the cashier at the convenience store. Therefore, the operability and convenience of the subcritical water treatment apparatus 1 are extremely high.

[0019] In the present embodiment, a part of the inner space of the discharge port 23 is configured to function as the liquid storage section 24. According to such a configuration, it is possible to prevent an increase in the number of parts of the pressure vessel 2 and a complication of the configuration of the pressure vessel 2. Therefore, it contributes to the downsizing of the subcritical water treatment apparatus 1. In addition, by changing the installation position of the discharge port 23, adjusting the inclination angle of the center line O23 of the discharge port 23 with respect to the center line O21 of the container body 21, etc., the entire internal space of the discharge port 23 can also be made to function as the liquid storage section 24. Further, the liquid storage portion 24 may be configured independently of the discharge port 23. Examples of such a configuration include a recess formed by being recessed in the inner surface on the bottom surface side of the container body 21, a container fixed to the inner surface on the upper surface side of the container body 21 or suspended from the inner surface, and the like.

[0020] The partition plate 25 is provided at the boundary between the container body 21 and the discharge port 23. This partition plate 25 has a function of allowing the vapor of the liquid L to pass through but blocking the passage of the organic waste. According to such a configuration, it is possible to prevent or suppress the organic waste from mixing into the liquid L stored in the discharge port 23 (liquid storage portion 24). That is, the subcritical water treatment apparatus 1 can store the organic waste in the container body 21 in an isolated state separated from the liquid L stored in the liquid storage portion 24. And the isolated state is ensured by the presence of the partition plate 25. On the other hand, the generated vapor of the liquid L (gaseous subcritical water) can be sufficiently brought into contact with the organic waste, and its low molecular weight can be surely promoted.

[0021] The partition plate 25 shown in FIG. 2 forms a circular shape as a whole by fixing a plurality of fan-shaped plate members 251 so as to be deployable with respect to each other at the center. A plurality of through holes 2511 penetrating in the thickness direction are formed in each plate member 251. The liquid L can be supplied to the inner space (liquid storage portion 24) of the discharge port 23 through the through holes 2511, and the vapor of the liquid L can move into the container body 21 through the through holes 2511. When the liquid storage portion 24 is not provided inside the discharge port 23, the partition plate 25 does not need to be configured as shown in FIG. 2. In this case, the partition plate 25 only needs to be able to block the passage of the organic waste to the discharge port 23.

[0022] In this embodiment, the heating mechanism 4 is provided so as to cover the entire container body 21. However, the heating mechanism 4 may be provided so as to cover a part of the container body 21. For example, the heating mechanism 4 may be provided so as to cover the lower portion of the container body 21. In this case, the container body 21 and the inner space of the discharge port 23 can be efficiently heated with less power consumption. As a result, the vapor of the liquid L (gaseous subcritical water) can be smoothly generated with less power consumption. The heating mechanism 4 can be configured by a heating mechanism such as an alumina heater type, an oil heater type, a light heating (infrared) type, an IH heater type, or the like.

[0023] In addition, when there is a relatively large margin in the arrangement space, the subcritical water treatment apparatus 1 may be configured to have an external or internal high-pressure boiler instead of having the liquid storage portion 24. In this case, gaseous subcritical water or steam (hereinafter also collectively referred to as high-temperature steam) is supplied from the high-pressure boiler into the container body 21 and the heating mechanism 4. FIG. 3 is a conceptual diagram partially showing the subcritical water treatment apparatus when an external high-pressure boiler is attached. In FIG. 3, the configurations other than the heating mechanism 4, the container body 21, the discharge port 23, and the steam supply pipes 41 and 42 are omitted. The configurations omitted in FIG. 3 are the same as those in the case of having the liquid storage portion 24.

[0024] When the subcritical water treatment apparatus 1 has an attached high-pressure boiler, the heating mechanism 4 has a hollow structure (a double structure of the container body 21 and a jacket arranged at an interval from the container body 21). High-temperature steam is supplied into the container body 21 and the heating mechanism 4 respectively through the steam supply pipes 41 and 42 connected to the high-pressure boiler. When high-temperature steam is supplied into the heating mechanism 4 through the steam supply pipe 41, the inside of the container body 21 is heated. When the inside of the container body 21 is heated, the high-temperature steam supplied into the container body 21 through the steam supply pipe 42 continues to be heated. Then, when the temperature and pressure inside the container body 21 reach a predetermined temperature and pressure described later, the inside of the container body 21 is filled with gaseous subcritical water. When the pressure vessel 2 is accompanied by a high-pressure boiler instead of having the liquid storage section 24, since high-temperature steam is supplied into the vessel main body 21 from the high-pressure boiler, gaseous subcritical water can be generated in a short time after starting the subcritical water treatment apparatus 1. Therefore, the time required for the entire subcritical water treatment can be shortened.

[0025] The stirring mechanism 3 includes a rotating shaft 31, a plurality (six in this embodiment) of stirring blades 32, a motor 33, a belt 34, and a pedestal 35. The rotating shaft 31 is arranged along the center line O21 of the vessel main body 21, and one end portion thereof penetrates the vessel main body 21. A sealing structure (not shown) is provided at the portion where the rotating shaft 31 penetrates the vessel main body 21, and the airtightness of the vessel main body 21 is maintained. The motor 33 is installed on the pedestal 35. The rotating shaft of the motor 33 is connected to the end portion of the rotating shaft 31 protruding from the vessel main body 21 via the belt 34. Thereby, the rotational force of the motor 33 can be transmitted to the rotating shaft 31. Six stirring blades 32 are provided on this rotating shaft 31 so as to be spaced apart from each other along the direction along the center line O21 (the longitudinal direction of the rotating shaft 31), and are arranged at substantially equal intervals (substantially 180° intervals) along the circumferential direction of the rotating shaft 31.

[0026] FIG. 4 is a diagram showing an enlarged view of the stirring blade. FIG. 5 is a diagram showing the relationship among the pressure vessel 2 (vessel main body 21), the stirring mechanism 3 (rotating shaft 31 and stirring blades 32), and the discharge port 23 when viewed from the upper surface side of the subcritical water treatment apparatus 1. In FIG. 5, a part of the subcritical water treatment apparatus 1 is shown in cross section. Also, in FIG. 5, the configurations other than the heating mechanism 4, the vessel main body 21, the discharge port 23, the rotating shaft 31, and the stirring blades 32 are omitted. In FIG. 5, the stirring blade 32 located below the rotating shaft 31 is shown by a broken line. As shown in FIG. 1 and the like, the plurality of stirring blades 32 have the same shape as each other. And each stirring blade 32 has a columnar blade shaft portion 321 and a blade portion 322 provided on the side opposite to the rotating shaft 31 of the blade shaft portion 321.

[0027] Each stirring blade 32 (blade shaft portion 321) protrudes radially outward from the rotary shaft 31 along the intersection line I that is substantially orthogonal to the center line O21 of the container body 21. In the present embodiment, each blade portion 322 includes two main surfaces (flat surfaces) 3221 and two side surfaces 3222 that connect the main surfaces 3221. The main surface 3221 is substantially parallel to the intersection line I and is inclined at an inclination angle θ with respect to the center line O21 of the container body 21. That is, each stirring blade 32 includes a main surface 3221 that is substantially parallel along the intersection line I and inclined with respect to the center line O21. Note that the shape of the side surface 3222 is not particularly limited, but in the present embodiment, it is flat and inclined at a predetermined inclination angle with respect to the center line O21 of the container body 21. Further, in the present embodiment, the angle formed by the main surface 3221 and the side surface 3222 is approximately 90°. Also, the top surface (the surface opposite to the blade shaft portion 321) of each blade portion 322 has an arc shape corresponding to the shape of the inner surface of the container body 21. The inclination angle θ is the smaller of the two angles formed by the main surface 3221 and the center line O21.

[0028] When having a horizontal pressure vessel 2 with the center line O21 along the horizontal direction like the subcritical water treatment apparatus 1 of the present embodiment, it may be difficult to move the organic waste and the treatment material accommodated in the pressure vessel 2 in the direction along the center line O21. In this case, the organic waste cannot be sufficiently stirred, the opportunity of contact with the gaseous subcritical water is reduced, and the treatment efficiency cannot be improved. Therefore, in the subcritical water treatment apparatus 1 of the present embodiment, it was decided to provide each stirring blade 32 with a main surface (flat surface) 3221 that is inclined with respect to the center line O21. By providing such a main surface 3221, when the motor 33 rotationally drives the rotary shaft 31, the main surface 3221 is brought into contact with the organic waste in the container body 21, and the organic waste can be moved by being pushed in the direction along the center line O21. Therefore, the organic waste can be sufficiently stirred, and the treatment efficiency is improved.

[0029] Specifically, by rotating the rotary shaft 31 forward or backward by the motor 33, the organic waste in the container body 21 can be moved and stirred not only in the vertical up-and-down direction but also in the direction along the center line O21. Further, after subjecting the organic waste to subcritical water treatment, the resulting treated material can be moved near the discharge port 23, so that the treated material can be quickly discharged from the discharge port 23. Furthermore, since the stirring blades 32 are provided so as to be separated from each other, the organic waste moving in the direction along the center line O21 can be bounced upward (scooped up) in the vertical direction and then dropped downward between the stirring blades 32. Thereby, when subjecting the organic waste to subcritical water treatment, it is possible to suppress the organic waste from moving more than necessary in the direction along the center line O21. For this reason, it is possible to prevent the forward and reverse rotations of the rotary shaft 31 from being frequently repeated.

[0030] In the present embodiment, all the stirring blades 32 have the same shape as each other. In this case, it can be expected that the design cost, manufacturing cost, maintenance cost, etc. can be reduced as compared with the case where the stirring blades 32 have different shapes from each other. Also, since all the stirring blades 32 have the same shape as each other, two adjacent stirring blades 32 are provided with a main surface 3221 having a substantially equal inclination angle θ with respect to the center line O21. Thereby, it becomes easier to move the organic waste and the treated material in the container body 21 in the direction along the center line O21 at a constant speed. Therefore, the smoothness when moving the organic waste and the treated material can be improved.

[0031] The inclination angle θ of the main surface 3221 with respect to the center line O21 is preferably about 30 to 70°, and more preferably about 35 to 65°. By configuring in this way, when the motor 33 rotationally drives the rotary shaft 31, the main surface 3221 becomes more likely to push and move the organic waste, so that the treatment efficiency of the organic waste is further improved. Also, since the treated material obtained by performing subcritical water treatment can be easily moved near the discharge port 23, the treated material can be quickly discharged from the discharge port 23.

[0032] Also, for the main surface 3221 with an inclination angle θ of about 30 to 70°, it may be set such that the inclination angle θ with respect to the center line O21 becomes larger as the main surface 3221 closer to the discharge port 23. In this case, as it approaches the discharge port 23, the movement in the direction along the center line O21 of the processed material can be suppressed. Therefore, when discharging the processed material, it can be expected that it will be easier to accumulate around the discharge port 23, and the processed material can be discharged more smoothly from the discharge port 23. Instead of gradually increasing the inclination angle θ as it approaches the discharge port 23, only the main surface 3221 closer to the discharge port 23 may have a larger inclination angle θ with respect to the center line O21.

[0033] Also, for the main surface 3221 with an inclination angle θ of about 30 to 70°, it may be set such that the inclination angle θ with respect to the center line O21 becomes smaller as the main surface 3221 closer to the inlet 22. In this case, as it gets closer to the inlet 22, the movement in the direction along the center line O21 of the organic waste can be promoted. Therefore, it can be expected to prevent the organic waste introduced from the inlet 22 from staying around the inlet 22, and the subcritical water treatment can be performed smoothly. Instead of gradually decreasing the inclination angle θ as it approaches the inlet 22, only the main surface 3221 closer to the inlet 22 may have a smaller inclination angle θ with respect to the center line O21.

[0034] Also, in this embodiment, since steam is supplied from the partition plate 25, there may be a large amount of highly active gaseous subcritical water near the partition plate 25. Therefore, for the main surface 3221 with an inclination angle θ of about 30 to 70°, it may be set such that the inclination angle θ with respect to the center line O21 becomes smaller as the main surface 3221 closer to the partition plate 25. Thereby, in the location where there is a large amount of highly active gaseous subcritical water, the movement in the direction along the center line O21 of the organic waste is suppressed, so the efficiency of the subcritical water treatment can be improved.

[0035] Also, when the maximum length in the direction perpendicular to the intersection line I of the main surface 3221 is X [mm] and the diameter of the container body 21 is Y [mm], it is preferably about 0.2 to 0.5, and more preferably about 0.25 to 0.45 for X / Y. By configuring in this way, it is possible to sufficiently secure the contact area between the organic waste and the main surface 3221, and it becomes easier to move the organic waste in the direction along the center line O21. Furthermore, it becomes easier to drop the organic waste scraped up by the stirring blade 32 vertically downward between adjacent stirring blades 32. Therefore, since the main surface 3221 can move the organic waste in the direction along the center line O21 at an appropriate speed, the treatment efficiency of the organic waste can be further improved. For example, in the case of the container body 21 with a volume of 3000 L, X / Y is preferably set to about 0.35, and in the case of the container body 21 with a volume of 400 L, X / Y is preferably set to about 0.34.

[0036] In addition, in the stirring blade 32, the blade shaft portion 321 and the blade portion 322 may be integrally formed, or may be formed as separate bodies and connected to each other. In the latter case, it can be used by replacing with blade portions 322 having different shapes. The shapes of the stirring blades 32 do not have to be the same as each other, and may be different from each other. For example, a plurality of sets of stirring blades with different shapes may be provided. Also, the shape of the stirring blade 32 may be configured so that the function varies depending on the installation position. For example, the stirring blade 32 at the central portion may be configured in a shape that makes it easy to move the organic waste in the direction along the center line O21, and the stirring blade 32 at the end portion may be configured in a shape that makes it easy to scrape out the organic waste. An example in which the shapes of the stirring blades are different from each other will be described in detail in Modification 4.

[0037] The number of main surfaces 3221 provided on the stirring blade 32 is not limited to two, and may be one or three or more. Also, the shape of the main surface 3221 is not limited to the shape shown in the figure, and may be, for example, a trapezoid, a triangle, a pentagon, a semi-circle, etc. Examples in which the number and shape of the main surfaces are different from those of the present embodiment will be described in detail in Modification 4.

[0038] The shape of the wing shaft portion 321 is not limited to a cylindrical shape, and may be, for example, a frustum of a cone shape, a quadrangular column shape, or the like. Also, the number of stirring wings 32 installed is not limited to six, and may be two, three, four, or seven or more. Also, the installation interval of the stirring wings 32 is not limited to 180° intervals along the circumferential direction of the rotating shaft 31, and may be, for example, 60° intervals, 90° intervals, 120° intervals, or 210° intervals along the circumferential direction.

[0039] Furthermore, the installation interval of the stirring wings 32 along the circumferential direction of the rotating shaft 31 may be non-uniform along the center line O21. For example, the stirring wings 32 may be installed at 90° intervals along the circumferential direction of the rotating shaft 31 at the end of the container body 21, and may be installed at 180° intervals along the circumferential direction of the rotating shaft 31 at the center. Also, a plurality of stirring wings 32 may be provided along the circumferential direction of the rotating shaft 31 at the same position in the direction along the center line O21. That is, the plurality of stirring wings 32 may be located on the same circumference of the rotating shaft 31. For example, at a location where organic waste and the material to be treated are likely to stay (for example, the end of the container body 21), a plurality of stirring wings 32 may be provided on the same circumference of the rotating shaft 31. An example in which the installation interval of the stirring wings 32 is non-uniform and a plurality of stirring wings 32 are provided on the same circumference of the rotating shaft 31 will be described in detail in Modification 5.

[0040] <Subcritical water treatment> Next, the subcritical water treatment in the subcritical water treatment apparatus 1 of the present embodiment will be described. FIG. 6 is a flowchart showing the flow of subcritical water treatment.

[0041] In S101, with the lid portion 233 of the discharge port 23 closed, the lid portion 223 of the inlet port 22 is opened, and the liquid L is introduced into the liquid storage portion 24 through the opening 222 and the through hole 2113. From this liquid L, the vapor of the liquid L (gaseous subcritical water) necessary for subcritical water treatment can be obtained. Subsequently, in S102, organic waste is introduced into the container body 21 through the opening 222 and the through-hole 2113. After the organic waste is introduced, the lid portion 223 is closed. When the lid portion 223 is closed, the pressure vessel 2 is in a sealed state.

[0042] In S103, the inside of the container body 21 is heated by activating the heating mechanism 4. When the heat of the container body 21 is transmitted to the liquid storage portion 24, vapor is generated from the liquid L in the liquid storage portion 24. When this vapor is supplied into the container body 21 through the through-hole 2511 of the partition plate 25, the pressure inside the sealed pressure vessel 2 rises. Also, the rotary shaft 31 is rotated by activating the motor 33. That is, the stirring mechanism 3 is activated to start stirring the organic waste.

[0043] At this time, as described above, by the forward or reverse rotation of the rotary shaft 31 by the motor 33, the main surface 3221 can push the organic waste and move the organic waste in the direction along the center line O21. During this movement, the organic waste is scraped upward vertically by the stirring blades 32, and the organic waste is dropped vertically between the plurality of stirring blades 32 spaced apart from each other. Thereby, unnecessary movement of the organic waste can be prevented, so that the number of repeated forward and reverse rotations of the rotary shaft 31 by the motor 33 can be suppressed. Therefore, subcritical water treatment can be performed with power saving.

[0044] Next, in S104, it is confirmed whether the pressure and temperature inside the pressure vessel 2 have reached the specified values. If the pressure or temperature has not reached the specified value, the process remains in S104. If both the pressure and temperature have reached the specified value, the process proceeds to S105. The specified values of the pressure and temperature serving as the criteria for the determination in S104 are the values of the temperature and pressure required for subcritical water treatment, which will be described later.

[0045] In S105, it is confirmed whether a certain period of time has elapsed. If the certain period of time has not elapsed, the process remains in S105. If the certain period of time has elapsed, the process proceeds to S106. The time serving as the criterion for the determination in S105 is the time required for subcritical water treatment, which will be described later. As described above, the subcritical water treatment apparatus 1 of the present embodiment includes a main surface 3221 inclined with respect to the center line O21 and has a plurality of stirring blades 32 spaced apart from each other. Therefore, the organic waste can be efficiently subjected to subcritical water treatment while being moved at an appropriate speed not only in the vertical up-and-down direction but also in the direction along the center line O21 (that is, while being sufficiently stirred). As a result, it can be expected to shorten the time required for subcritical water treatment.

[0046] In S106, when the necessary time has elapsed under the temperature and pressure required for subcritical water treatment, the heating mechanism 4 is stopped. Also, the pressure vessel valves 224 or 225 are slightly opened. That is, the pressure in the pressure vessel 2 is reduced while the temperature is decreased. Subsequently, in S107, it is confirmed whether the pressure and temperature in the pressure vessel 2 have sufficiently decreased. If the pressure or temperature has not sufficiently decreased, the process remains in S107, and if the pressure and temperature have sufficiently decreased, the process proceeds to S108. In S107, it is confirmed whether the pressure and temperature in the pressure vessel 2 have decreased to a pressure and temperature at which the processed material can be safely taken out.

[0047] In S108, the lid portion 233 of the discharge port 23 is opened, and the processed material in the container body 21 is taken out. When taking out the processed material, by rotating the rotating shaft 31, the stirring blade 32 moves the processed material near the discharge port 23. When the discharge of the processed material is completed and the stirring mechanism 3 is stopped, this subcritical water treatment is terminated.

[0048] FIG. 7 is a flowchart showing the flow of subcritical water treatment. In FIG. 7, the flow of subcritical water treatment is shown when the subcritical water treatment apparatus 1 has a high-pressure boiler instead of the liquid storage portion 24. S201, S204 to S205, and S207 to S208 in FIG. 7 are the same as S102, S104 to S105, and S107 to S108 described with reference to FIG. 6, respectively, and thus the description thereof is omitted. In S202, start the high-pressure boiler. The high-pressure boiler supplies high-temperature steam for generating gaseous subcritical water required for subcritical water treatment.

[0049] In S203, supply the high-temperature steam from the high-pressure boiler into the heating mechanism 4 and the container body 21 via the steam supply pipes 41 and 42, respectively. At this time, first supply the high-temperature steam into the heating mechanism 4 via the steam supply pipe 41. By preheating the inside of the container body 21 via the heating mechanism 4, it is possible to prevent the high-temperature steam supplied into the container body 21 from cooling and condensing in the container body 21. Also, in S203, start the stirring mechanism 3 to start stirring the organic waste, similar to S103 in FIG. 6.

[0050] In S206, when the required time has elapsed under the temperature and pressure required for subcritical water treatment, stop the high-pressure boiler. Also, slightly open the pressure vessel valve 224 or 225. That is, lower the temperature while reducing the pressure inside the pressure vessel 2. According to the flow described above, subcritical water treatment can be performed using the subcritical water treatment apparatus 1 of the present embodiment. Note that after S106 and S206, the heating of the processed material by the heating mechanism 4 may be continued (in the case of S206, continue supplying high-temperature steam to the heating mechanism 4). Thereby, the water content of the processed material can be reduced (adjusted). Such treatment is effective when using the processed material in the production of pellets for fuel use as described later.

[0051] In the case of subcritical water treatment shown in FIG. 6, the amount of the liquid L used for subcritical water treatment is not particularly limited, but is preferably about 0.001 to 0.1 times the volume of the container body 21, and more preferably about 0.005 to 0.05 times. By using such an amount of the liquid L, it is possible to generate sufficient gaseous subcritical water to reduce the molecular weight of the organic waste. The temperature of the gaseous subcritical water (vapor of liquid L) is preferably about 150 to 230 °C, more preferably about 160 to 220 °C. Also, the pressure is preferably about 15 to 25 atm, more preferably about 18 to 22 atm. Specifically, the temperature and pressure of the gaseous subcritical water are preferably about 200 °C and about 20 atm.

[0052] The circumferential speed of the outer end in the radial direction of the stirring blade 32 is preferably 2 m / s or more, more preferably 3 m / s or more. Note that the upper limit value of the circumferential speed is usually about 7 m / s. With such a circumferential speed, it is possible to move the organic waste in the direction along the center line O21 at an appropriate speed and avoid using a high-power and expensive motor 33. The time in the subcritical water treatment is appropriately set according to the type of organic waste and the like and is not particularly limited, but is preferably about 0.1 to 10 hours, more preferably about 0.5 to 5 hours.

[0053] This subcritical water has a dielectric constant of 15 to 45, which is equivalent to that of a low-polarity solvent. Therefore, it can dissolve many organic substances. Furthermore, the subcritical water has an ion product of 1×10 -12 ~1×10 -11 mol 2 / kg 2 and shows a large ratio of separation into hydrogen ions and hydroxide ions, thus exhibiting a strong hydrolysis effect. Note that the dielectric constant of water at room temperature and atmospheric pressure is about 80, and the ion product of water at a temperature of about 25 °C and atmospheric pressure is 1×10 -14 mol 2 / kg 2 is.

[0054] The solubilization rate of the low-molecular-weight organic waste (i.e., the treated product) is preferably 50% or more, more preferably 70% or more, and even more preferably 85% or more. Here, the solubilization rate is the ratio of soluble organic matter to total organic matter after subcritical water treatment, and a higher numerical value means that the organic matter is more advanced in the process of being broken down into smaller molecules. Specific examples of the low-molecular-weight products of organic waste include, for example, carbohydrates, proteins, fats, etc. being decomposed, and the corresponding saccharides, amino acids, higher fatty acids, etc. Also, although the subcritical water treatment in the subcritical water treatment apparatus 1 is a batch treatment by its nature, in the present invention, it can be carried out at a rate of several batches per day. <Subcritical water treatment unit> Next, the subcritical water treatment unit of the present invention will be described. FIG. 8 is a conceptual diagram showing an embodiment of the subcritical water treatment unit. The subcritical water treatment unit 100 shown in FIG. 8 includes the above-described subcritical water treatment apparatus 1 and a pelletizing / semi-carbonizing apparatus 10 connected to the subcritical water treatment apparatus 1. The mixture (pellet raw material) containing the material to be treated may be semi-carbonized by a semi-carbonizing apparatus that semi-carbonizes the pellet raw material containing the material to be treated, and then pelletized by a pelletizing apparatus, or vice versa. Here, the pelletizing apparatus is an apparatus that pelletizes the pellet raw material or the pellet raw material after semi-carbonization to obtain pellets.

[0055] Note that the pelletizing / semi-carbonizing apparatus 10 may be provided with a mixing apparatus (not shown) that mixes the material to be treated and the woody biomass as needed to obtain a mixture of these as a pellet raw material. Organic waste has different compositions depending on the collection area and time, and the calorific value of the treated material obtained by subcritical water treatment also varies. For the purpose of complementing (adjusting) such fluctuations in the calorific value, woody biomass can be mixed with the material to be treated. Thereby, pellets (solid fuel) having a stable calorific value equivalent to that of coal and a quality equivalent to the quality classification in terms of the mass fraction of total chlorine content defined by RPF can be produced well in an extremely short time.

[0056] Examples of the woody biomass that can be used in the present invention include the end portions (so-called "hazardous materials") generated when logs (round timbers) cut from mountains are processed into lumber (boards, columns, etc.), crushed materials such as the bark of round timbers, and waste paper made from lumber as raw materials. The obtained pellets generate CO2 when burned, but if they are woody biomass, they only return the CO2 absorbed by the forest trees to the atmosphere, so they are carbon neutral. Therefore, for example, "biomass energy fuel" such as the pellets obtained in the present embodiment can also be said to be an ecological fuel.

[0057] In addition, as long as the obtained pellets can be suitably used as fuel for the target device, their size, shape, etc. are not particularly limited. In addition, the pellets obtained by semi-carbonization are composed of carbides with high purity while the moisture content and the content of volatile organic components are suppressed. Therefore, the pellets have an increased calorific value and are excellent in durability and storage stability in the natural environment.

[0058] The semi-carbonization treatment by the semi-carbonization device is performed by heat-treating the pellet raw material in an atmosphere with a low oxygen concentration. The temperature of the heat treatment is preferably about 200 to 700 °C, more preferably about 200 to 300 °C. Also, the time of the heat treatment is preferably about 1 to 24 hours, more preferably about 1 to 3 hours. By performing the semi-carbonization treatment under such conditions, the pellet raw material can be surely brought into a semi-carbonized state. Here, the semi-carbonized state means a state in which about half of the pellet raw material is converted into carbide.

[0059] For the pelletizing device, for example, a strand type extruder, a hot cut type extruder, etc. can be used. In addition, as shown in FIG. 8, the subcritical water treatment unit 100 of the present embodiment has a container 200 that can be transported while accommodating the subcritical water treatment device 1 and the pelletizing device / semi-carbonization device 10. The container 200 is loaded on a large vehicle 300 in a state where the subcritical water treatment device 1 and the pelletizing device / semi-carbonization device 10 are accommodated. Thereby, the subcritical water treatment unit 100 can be moved to a predetermined location according to the purpose.

[0060] The volume of the container 200 is preferably about 10 to 70 m 3 and more preferably about 15 to 65 m 3 and even more preferably about 20 to 50 m 3 For a container 200 of such a size, it is easy to secure an installation location even in an urban area.

[0061] Furthermore, the subcritical water treatment unit 100 may have a water treatment device / deodorization treatment device according to the purpose, instead of the pelletizing device / semi-carbonization device 10 or in combination with the pelletizing device / semi-carbonization device 10. Here, the water treatment device is a device that treats the gas discharged from the subcritical water treatment device 1, and the treatment method is selected according to the purpose and standard of water treatment. This water treatment device can be composed of, for example, a device that performs pressurized flotation treatment. The deodorization treatment device is a device that deodorizes the gas discharged from the subcritical water treatment device 1 and can be composed of, for example, an adsorption filter device.

[0062] The gas discharged from the subcritical water treatment device 1 may be treated by the water treatment device and then deodorized by the deodorization treatment device, or vice versa. Note that the subcritical water treatment unit 100 only needs to have the subcritical water treatment device 1 and at least one of the pelletizing device, semi-carbonization device, water treatment device, and deodorization treatment device. In this case, the container 200 accommodates the subcritical water treatment device 1 and the at least one device. Therefore, the plurality of devices constituting the subcritical water treatment unit 100 may be housed in a single container 200 or separately housed in a plurality of containers 200 according to the volume (size) of the container 200, the volume of the container body 21, the presence or absence of accessories for the high-pressure boiler, etc. In the latter case, the volumes of the plurality of containers 200 may be the same or different from each other.

[0063] As described above, according to the present embodiment, it is possible to provide the subcritical water treatment apparatus 1 and the subcritical water treatment unit 100 that can perform subcritical water treatment while moving organic waste at an appropriate speed and can improve the treatment efficiency.

[0064] <Modification Example> Hereinafter, each modification example of the subcritical water treatment apparatus 1 of the present embodiment will be described. In each figure, the same reference numerals are given to the members similar to the above-described configuration example (see FIG. 1 etc.). In addition, each modification example of the subcritical water treatment apparatus 1 will be described, but the description will focus on the differences from the above-described configuration example, and the description of the same matters will be omitted.

[0065] (Modification Example 1) FIG. 9 is a conceptual diagram showing a subcritical water treatment apparatus according to Modification Example 1 in a partial cross section. In FIG. 9, the discharge port 23 is shown by a broken line. FIG. 10 is a conceptual diagram showing a subcritical water treatment apparatus according to Modification Example 1 in a partial cross section when viewed from the side (right side in FIG. 9). In FIG. 10, the configurations other than the heating mechanism 4, the container body 21, the inlet 22, the discharge port 23, the liquid storage portion 24, and the gantry 29 are omitted. FIG. 11 is a diagram showing the relationship between the pressure vessel, the stirring mechanism, and the discharge port when the subcritical water treatment apparatus 1 according to Modification Example 1 is viewed from the upper surface side. In FIG. 11, a part of the subcritical water treatment apparatus 1 is shown in a cross section. In FIG. 11, the configurations other than the heating mechanism 4, the container body 21, the discharge port 23, the rotating shaft 31, and the stirring blade 32 are omitted. In FIG. 11, the stirring blade 32 located below the rotating shaft 31 is shown by a broken line.

[0066] In Modification Example 1 of the subcritical water treatment apparatus 1, the configuration of the container main body 21 and the configuration of the stirring mechanism 3 are different, but other than that, it is the same as the above-described configuration example. That is, as shown in FIGS. 9 and 10, in the subcritical water treatment apparatus 1 according to Modification Example 1, the discharge port 23 is located at the central portion in the direction along the center line O21 of the container main body 21. Further, as shown in FIGS. 9 and 11, the stirring blade 32 disposed on the right side (one side along the center line O21) with respect to the discharge port 23 has a line-symmetrical shape with respect to the stirring blade 32 disposed on the left side (the other side). Therefore, the inclination direction of the main surface (flat surface) 3221 located on the right side (one side along the center line O21) with respect to the discharge port 23 is opposite to the inclination direction of the main surface (flat surface) 3221 located on the left side (the other side).

[0067] After the subcritical water treatment, when the rotary shaft 31 is rotated in one direction, the main surface 3221 disposed on the right side with respect to the discharge port 23 and the main surface 3221 disposed on the left side push out the processed material in opposite left and right directions. Therefore, by the rotation of the rotary shaft 31 in one direction, the processed material located on the right side with respect to the discharge port 23 can be moved to the left side, and the processed material located on the left side with respect to the discharge port 23 can be moved to the right side. Thereby, even when the discharge port 23 is located at the central portion of the subcritical water treatment apparatus 1, the processed material can be moved to the vicinity of the discharge port 23 by the rotation of the motor 33 in one direction. Therefore, the processed material can be discharged from the discharge port 23 quickly and with power saving.

[0068] In this Modification Example 1, if the main surface 3221 is inclined in opposite directions on the left and right sides of the discharge port 23, the stirring blade 32 does not necessarily have a line-symmetrical shape on the left and right sides of the discharge port 23. Further, in this Modification Example 1, the discharge port 23 does not have to be located at the central portion along the center line O21 of the container main body 21, and may be offset toward one end side from this central portion. For example, the discharge port 23 may be provided at a position about 1 / 3 of the length from the right end in the direction along the center line O21 of the container main body 21. Also in this case, it is sufficient that the stirring blade 32 has a main surface 3221 that is inclined in opposite directions on the left and right sides of the discharge port 23.

[0069] (Modification Example 2) FIG. 12 is a conceptual diagram showing a subcritical water treatment apparatus according to Modification Example 2, partially in cross section. FIG. 13 is a diagram showing the relationship among the pressure vessel, the stirring mechanism, and the discharge port when viewed from the upper surface side of the subcritical water treatment apparatus according to Modification Example 2. In FIG. 13, a part of the subcritical water treatment apparatus 1 is shown in cross section. Also, in FIG. 13, the configurations other than the heating mechanism 4, the container main body 21, the discharge port 23, the rotating shaft 31, and the stirring blades 32 are omitted. In FIG. 13, the stirring blades 32 located below the rotating shaft 31 are shown by broken lines.

[0070] In Modification Example 2 of the subcritical water treatment apparatus 1, the configuration of the container main body 21 and the configuration of the stirring mechanism 3 are different, and other than that, it is the same as the above configuration example. That is, as shown in FIG. 12, in the subcritical water treatment apparatus 1 according to Modification Example 2, the discharge ports 23 are arranged at both ends in the direction along the center line O21 of the container main body 21 of the pressure vessel 2. Also, as shown in FIGS. 12 and 13, the stirring blades 32 arranged on the right side of the center line C in the direction along the center line O21 of the container main body 21 have a line-symmetrical shape with respect to the stirring blades 32 arranged on the left side. Therefore, the inclination direction of the main surface 3221 located on the right side of the center line C is opposite to the inclination direction of the main surface 3221 located on the other side.

[0071] Thus, since the inclination directions of the main surfaces 3221 are opposite on the left and right of the center line C, when the rotating shaft 31 rotates in one direction, the main surface 3221 arranged on the right side of the center line C and the main surface 3221 arranged on the left side push the processed material in opposite left and right directions. Therefore, by the rotation of the rotating shaft 31 in one direction, the processed material located on the right side of the center line C can be moved to the right, and the processed material located on the left side of the center line C can be moved to the left. Accordingly, when discharging the processed material from the discharge port 23, by the rotation of the rotating shaft 31 in one direction, the processed material can be moved to the vicinity of the discharge port 23 closer to the processed material. Thereby, even when the discharge ports 23 are located at both ends of the subcritical water treatment apparatus 1, the processed material can be discharged from the discharge port 23 quickly and with power saving.

[0072] In addition, since the discharge ports 23 are provided at both ends respectively, the movement of the processed material in the direction along the center line O21 of the processed material can be shortened, and the amount of the processed material discharged from each discharge port 23 can be reduced. Therefore, the processed material can be discharged from the discharge port 23 in a short time. Therefore, the subcritical water treatment of the next batch can be started smoothly. Note that not only the discharge ports 23 but also a plurality of inlet ports 22 may be provided. Note that in this Modification 2, if the main surface 3221 is inclined in opposite directions on the right side and the left side of the center line C, the stirring blade 32 does not have to have a line-symmetric shape on the left and right of the center line C.

[0073] (Modification 3) FIG. 14 is a conceptual diagram showing a subcritical water treatment apparatus according to Modification 3, partially in cross section. In Modification 3 of the subcritical water treatment apparatus 1, the configuration of the container main body 21 is different, and other than that, it is the same as the above-described configuration example. That is, in the subcritical water treatment apparatus 1 according to Modification 3, the inlet port 22 is disposed at the left end of the container main body 21, that is, at the end opposite to the discharge port 23.

[0074] When the rotary shaft 31 is rotated so that the main surface 3221 moves the organic waste to the right, the organic waste introduced from the inlet port 22 moves from the left end of the container main body 21 to the vicinity of the discharge port 23 located at the right end. If the subcritical water treatment is performed while moving the organic waste by making the most of the length in the direction along the center line O21 of the container main body 21 in this way, sufficient subcritical water treatment can be performed between the time when the organic waste is introduced from the inlet port 22 and the time when it reaches the discharge port 23. In that case, between the time when the stirring mechanism 3 is started in S103 of FIG. 6 (or S203 of FIG. 7) and the time when the stirring mechanism 3 is stopped in S108 of FIG. 6 (or S208 of FIG. 7), the subcritical water treatment can be performed by rotating the rotary shaft 31 in one direction.

[0075] In other words, the subcritical water treatment can be performed only by rotating the rotary shaft 31 in the same direction between the time when the organic waste is introduced from the inlet port 22 and the time when the processed material is discharged from the discharge port 23. Therefore, in the subcritical water treatment apparatus 1 according to the third modification, it is possible to suppress the power consumption by switching the forward and reverse rotations of the rotary shaft 31. Of course, depending on the length in the direction along the center line O21 of the container body 21, the type and amount of the organic waste, the conditions of temperature and pressure, etc., the organic waste may be stirred by both the forward and reverse rotations of the rotary shaft 31.

[0076] (Third Modification) FIG. 15 is a conceptual diagram showing a subcritical water treatment apparatus according to the third modification, partially in cross section. In the third modification of the subcritical water treatment apparatus 1, the configuration of the stirring mechanism 3 is different, and other than that, it is the same as the above-described configuration example. That is, the stirring mechanism 3 of the third modification has stirring blades of two types of shapes. Here, a stirring blade having a shape different from the above-described stirring blade 32 is referred to as a second stirring blade 36. In the third modification, two second stirring blades 36 are arranged on both sides of a plurality (four in this modification) of stirring blades 32 in the direction along the center line O21.

[0077] FIG. 16 is a diagram showing an enlarged view of the second stirring blade according to the third modification. FIG. 17 is a diagram showing the relationship between the pressure vessel, the stirring mechanism, and the discharge port according to the third modification. FIG. 17 shows the relationship when viewed from the upper surface side of the subcritical water treatment apparatus, and a part of the subcritical water treatment apparatus is shown in cross section. In FIG. 17, the configurations other than the heating mechanism 4, the container body 21, the discharge port 23, the rotary shaft 31, the stirring blade 32, and the second stirring blade 36 are omitted. Further, in FIG. 17, the stirring blade 32 and the second stirring blade 36 located below the rotary shaft 31 are shown by broken lines.

[0078] The second stirring blade 36 does not have a boundary between the blade portion and the blade shaft portion. The second stirring blade 36 projects radially outward from the rotary shaft 31 along the intersection line I2 that is substantially orthogonal to the center line O21 of the container body 21. Each second stirring blade 36 has one main surface (flat surface) 361 as the surface facing the inside in the direction along the center line O21. The main surface 361 is substantially parallel to the intersection line I2 and is configured to form an inclination angle θ2 with the center line O21 of the container body 21. That is, the second stirring blade 36 has a main surface 361 that is substantially parallel along the intersection line I2 and inclined with respect to the center line O21. The inclination angle θ2 is the smaller of the two angles formed by the main surface 361 and the center line O21.

[0079] The outer portion 362 of the second stirring blade 36 has a rounded shape. This shape is designed to follow the roundness of the left and right ends of the inner surface of the container body 21. For this reason, the second stirring blades 36 located at both ends in the direction along the center line O21 of the plurality of stirring blades 32 can be arranged closer to the inner surface of the container body 21. Therefore, since the main surface 361 can push and move the organic waste and the treated material that have moved to the end of the container body 21 in the direction along the center line O21, it is possible to prevent the organic waste and the treated material from staying at the end of the container body 21. (Modification 5) FIG. 18 is a conceptual diagram showing a subcritical water treatment apparatus according to Modification 5 in a partial cross section. In Modification 5 of the subcritical water treatment apparatus 1, the configuration of the stirring mechanism 3 is different, and the rest is the same as in the above configuration example. That is, in the stirring mechanism 3 of Modification 5, the installation intervals of the stirring blades 32 are non-uniform. Also, a plurality of stirring blades 32 are provided on the same circumference of the rotating shaft 31.

[0080] Specifically, it is as follows. At each of the position (first position) farthest from the discharge port 23 along the center line O21 and the third farthest position (third position), two stirring blades 32 are provided on the same circumference of the rotating shaft 31. And at these positions, the two stirring blades 32 are provided at substantially 180° intervals.

[0081] On one hand, at each of the positions (the second, fourth, fifth, sixth, and seventh positions) that are the second, fourth, fifth, sixth, and seventh farthest from the discharge port 23, one stirring blade 32 is provided on the same circumference of the rotation axis. And the stirring blades 32 arranged at adjacent positions are provided at intervals of approximately 90°.

[0082] At each of the first and third positions close to the end of the container body 21 on the side opposite to the discharge port 23, since a plurality of stirring blades 32 are provided on the same circumference of the rotation axis 31, the organic waste or the material to be treated is easily pushed in the direction along the center line O21 by the main surface 3221. As a result, the organic waste or the material to be treated is sufficiently stirred in the direction along the center line O21 without staying at the end, so the subcritical water treatment efficiency is improved.

[0083] At the second position located between the first position and the third position, by providing only one stirring blade 32 on the same circumference of the rotation axis 31, the organic waste scraped vertically upward by the main surfaces 3221 of the stirring blades 32 at the first and third positions easily falls vertically downward at the second position. Therefore, it is possible to prevent the organic waste from moving too far in the direction along the center line O21, so that the power consumption due to repeatedly rotating the rotation axis 31 forward and backward can be suppressed.

[0084] At each of the fourth and fifth positions located at the central part along the center line O21 of the container body 21, by providing only one stirring blade 32 on the same circumference of the rotation axis 31, the organic waste scraped vertically upward by the main surface 3221 of the stirring blade 32 easily falls vertically downward. Thereby, in the central part of the container body 21 where the organic waste is difficult to stay, it is possible to prevent the organic waste from moving too far in the direction along the center line O21, so that the power consumption due to repeatedly rotating the rotation axis 31 forward and backward can be suppressed.

[0085] At each of the sixth and seventh positions near the discharge port 23, only one stirring blade 32 is provided on the same circumference of the rotation shaft 31. Thus, the processed material scraped upward vertically by the main surface 3221 of the stirring blade 32 is likely to fall vertically downward. As a result, when discharging the processed material from the discharge port 23, it becomes easier to retain the processed material near the discharge port 23, so it can be expected to discharge the processed material in a short time. Consequently, the subcritical water treatment of the next batch can be started smoothly, improving the subcritical water treatment efficiency.

[0086] According to the above configuration, subcritical water treatment can be performed while moving the organic waste at an appropriate speed, and the treatment efficiency of the organic waste can be improved. Furthermore, it may be provided in each of the aspects described below.

[0087] (1) A subcritical water treatment apparatus for subjecting organic waste to subcritical water treatment to obtain a processed material, comprising a pressure vessel having a center line along the horizontal direction, a stirring mechanism for stirring the organic waste accommodated in the pressure vessel, and a heating mechanism for heating the organic waste. The pressure vessel includes a container body, an inlet for introducing the organic waste into the container body, and a discharge port for discharging the processed material from the container body. The stirring mechanism includes a rotation shaft disposed along the center line, and a plurality of stirring blades protruding radially outward from the rotation shaft along an intersection line substantially orthogonal to the center line and provided at intervals from each other. Each of the stirring blades includes a flat surface that is substantially parallel along the intersection line and inclined with respect to the center line. Subcritical water treatment apparatus.

[0088] (2) In the subcritical water treatment apparatus according to (1) above, the inclination angle of the flat surface with respect to the center line is 30 to 70°. Subcritical water treatment apparatus.

[0089] (3) In the subcritical water treatment apparatus according to (2) above, the closer the flat surface is to the discharge port, the larger the inclination angle with respect to the center line. Subcritical water treatment apparatus.

[0090] (4) In the subcritical water treatment apparatus according to (2) above, in the flat surface closer to the inlet, the inclination angle with respect to the center line is smaller, the subcritical water treatment apparatus.

[0091] (5) In the subcritical water treatment apparatus according to any one of (1) to (4) above, when the maximum length in the direction orthogonal to the intersection line of the flat surface is X [mm] and the diameter of the container body is Y [mm], X / Y is 0.2 to 0.5, the subcritical water treatment apparatus.

[0092] (6) In the subcritical water treatment apparatus according to any one of (1) to (5) above, the discharge port is located at the center in the direction along the center line of the container body, and the inclination direction of the flat surface located on one side along the center line from the discharge port and the inclination direction of the flat surface located on the other side are opposite, the subcritical water treatment apparatus.

[0093] (7) In the subcritical water treatment apparatus according to any one of (1) to (6) above, two adjacent stirring blades are provided with flat surfaces having substantially equal inclination angles with respect to the center line, the subcritical water treatment apparatus.

[0094] (8) In the subcritical water treatment apparatus according to any one of (1) to (7) above, after the organic waste is introduced from the inlet, until the treated product is discharged from the discharge port, the rotating shaft is rotated only in the same direction, the subcritical water treatment apparatus.

[0095] (9) In the subcritical water treatment apparatus according to any one of (1) to (8) above, the volume of the container body is 200 to 5000 L, the subcritical water treatment apparatus.

[0096] (10) A subcritical water treatment unit, comprising the subcritical water treatment apparatus according to any one of (1) to (9) above, a semi-carbonization apparatus for semi-carbonizing pellet raw materials containing the object to be treated, a pelletizing apparatus for pelletizing the pellet raw materials or the pellet raw materials after semi-carbonization to obtain pellets, at least one apparatus among a water treatment apparatus for treating the gas discharged from the subcritical water treatment apparatus and a deodorization treatment apparatus for deodorizing the gas discharged from the subcritical water treatment apparatus, and a container capable of transporting the subcritical water treatment apparatus and the at least one apparatus in a contained state.

[0097] (11) In the subcritical water treatment unit according to (10) above, the volume of the container is 10 to 70 m 3 . A subcritical water treatment unit. Of course, this is not the limit.

[0098] Finally, although various embodiments according to the present invention have been described, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of reference numerals

[0099] 1: Subcritical water treatment apparatus 2: Pressure vessel 21: Container body 2113: Through hole 2123: Through hole 22: Inlet 221: Barrel part 222: Opening 223: Lid part 224: Pressure vessel valve 225: Pressure vessel valve 23: Outlet 231: Barrel part 232: Opening 233: Cover part 24: Liquid storage part 25: Partition board 251: Plate material 2511: Through hole 29: Stand 3: Stirring mechanism 31: Rotating shaft 32: Stirring blade 321: Blade shaft part 322: Blade part 3221: Main surface (flat surface) 3222: Side surface 33: Motor 34: Belt 35: Stand 36: Second stirring blade 361: Main surface (flat surface) 362: Outer part 4: Heating mechanism 41: Steam supply pipe 42: Steam supply pipe 10: Pelletizing device·Semicarbonization device 100: Subcritical water treatment unit 200: Container 300: Large vehicle C: Central line I: Intersecting line I2: Intersecting line L: Liquid O21: Center line O22: Center line O23: Center line θ: Inclination angle θ2: Inclination angle

Claims

1. A subcritical water treatment apparatus for treating organic waste with subcritical water to obtain a treated product, comprising: a pressure vessel having a center line along the horizontal direction, a stirring mechanism for stirring the organic waste accommodated in the pressure vessel, and a heating mechanism for heating the organic waste; the pressure vessel includes a vessel body, an inlet for introducing the organic waste into the vessel body, and an outlet for discharging the treated product from the vessel body; the stirring mechanism includes a rotating shaft arranged along the center line, and a plurality of stirring blades protruding radially outward from the rotating shaft along an intersection line substantially perpendicular to the center line and provided at intervals from each other; each of the stirring blades has a blade shaft portion and a blade portion provided on the side opposite to the rotating shaft of the blade shaft portion and having a flat surface substantially parallel to the intersection line and inclined with respect to the center line; among the two angles formed by the flat surface and the center line, the smaller inclination angle is 35 to 70°; a subcritical water treatment apparatus, wherein when the maximum length in the direction perpendicular to the intersection line of the flat surface is X [mm] and the diameter of the vessel body is Y [mm], X / Y is 0.2 to 0.

45.

2. The subcritical water treatment apparatus according to Claim 1, wherein the closer the flat surface is to the outlet, the larger the inclination angle with respect to the center line.

3. The subcritical water treatment apparatus according to Claim 1, wherein the closer the flat surface is to the inlet, the smaller the inclination angle with respect to the center line.

4. The subcritical water treatment apparatus according to Claim 1, wherein the outlet is located at the central portion in the direction along the center line of the vessel body, and the inclination directions of the flat surfaces located on one side and the other side along the center line from the outlet are opposite to each other.

5. The subcritical water treatment apparatus according to Claim 1, wherein two adjacent stirring blades are provided with flat surfaces having substantially equal inclination angles with respect to the center line.

6. The subcritical water treatment apparatus according to Claim 1, wherein the outlet is located at one end in the direction along the center line of the vessel body, and at the central portion in the direction along the center line of the vessel body, only one stirring blade is provided on the same circumference of the rotating shaft. In the subcritical water treatment apparatus, among the positions of the stirring blades in the direction along the center line of the container body, at the position farthest from the discharge port, a plurality of the stirring blades are provided on the same circumference of the rotating shaft.

7. In the subcritical water treatment apparatus according to claim 6, In the subcritical water treatment apparatus, among the positions of the stirring blades in the direction along the center line of the container body, at the position third farthest from the discharge port, a plurality of the stirring blades are provided on the same circumference of the rotating shaft.

8. In the subcritical water treatment apparatus according to claim 1, The discharge port is located at one end in the direction along the center line of the container body, In the subcritical water treatment apparatus, among the positions of the stirring blades in the direction along the center line of the container body, at the position farthest from the discharge port and the position third farthest from the discharge port, a plurality of the stirring blades are provided on the same circumference of the rotating shaft, In the subcritical water treatment apparatus, among the positions of the stirring blades in the direction along the center line of the container body, at the position second farthest from the discharge port, only one stirring blade is provided on the same circumference of the rotating shaft.

9. In the subcritical water treatment apparatus according to claim 1, The volume of the container body is 200 to 5000 L, in the subcritical water treatment apparatus.

10. A subcritical water treatment unit, The subcritical water treatment apparatus according to any one of claims 1 to 9, At least one device among a semi-carbonization device for semi-carbonizing the pellet raw material containing the object to be treated, a pelletizing device for pelletizing the pellet raw material or the pellet raw material after semi-carbonization to obtain pellets, a water treatment device for treating the gas discharged from the subcritical water treatment apparatus, and a deodorization treatment device for deodorizing the gas discharged from the subcritical water treatment apparatus, And a container capable of being transported in a state of accommodating the subcritical water treatment apparatus and the at least one device, a subcritical water treatment unit.

11. In the subcritical water treatment unit according to claim 10, The volume of the container is 10 to 70 m ３ This is a subcritical water treatment unit.

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