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 technology]

[0002] Patent Document 1 describes an organic waste treatment device that uses hydrothermal reactions under subcritical water conditions to decompose waste. This organic waste treatment device has a heat-resistant and pressure-resistant container and a screw blade installed in the container. The waste contained 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] Patent No. 4751977 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when waste is stirred with a screw blade as described in Patent Document 1, the waste moves significantly to one side along the axis (center line) of the screw blade within the heat-resistant and pressure-resistant container and becomes unevenly distributed. Therefore, in such an organic waste treatment device, it is necessary to frequently repeat forward and reverse rotation of the screw blade in order to sufficiently decompose the waste.

[0005] In view of the above circumstances, the present invention provides a subcritical water treatment device and a subcritical water treatment unit that can perform subcritical water treatment while moving organic waste at an appropriate speed along the center line of a stirring mechanism, thereby improving the efficiency of treating organic waste. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a subcritical water treatment apparatus for treating organic waste with subcritical water to obtain a treated product. The subcritical water treatment apparatus includes a pressure vessel having a center line along a horizontal direction, an agitation mechanism for agitating the organic waste contained in the pressure vessel, and a heating mechanism for heating the organic waste. The pressure vessel includes a vessel body, an inlet for feeding the organic waste into the vessel body, and an outlet for discharging the treated product from within the vessel body. The agitation mechanism includes a rotating shaft arranged along the center line, and a plurality of agitation blades spaced apart from one another and protruding radially outward from the rotating shaft along an intersection line substantially perpendicular to the center line. Each agitation blade includes a flat surface that is substantially parallel to the intersection line and inclined with respect to the center line.

[0007] According to this aspect, the organic waste can be moved at an appropriate speed along the center line of the stirring mechanism while undergoing subcritical water treatment, thereby improving the efficiency of treating the organic waste. [Brief description of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram showing, in partial cross section, an embodiment of a subcritical water treatment apparatus. [Diagram 2] FIG. 4 is a plan view showing the configuration of a separator. [Diagram 3] FIG. 2 is a conceptual diagram partially illustrating a subcritical water treatment apparatus equipped with an external high-pressure boiler. [Figure 4] FIG. [Diagram 5] 2 is a diagram showing the relationship between a pressure vessel, a stirring mechanism, and a discharge port when viewed from the top side of the subcritical water treatment apparatus. FIG. [Figure 6] 1 is a flowchart showing a flow of a subcritical water treatment. [Figure 7] 1 is a flowchart showing a flow of a subcritical water treatment. [Figure 8] FIG. 1 is a conceptual diagram illustrating an embodiment of a subcritical water treatment unit. [Figure 9] 1 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to a first modified example. [Figure 10]FIG. 1 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to a first modified example, as viewed from the side. [Figure 11] 1 is a diagram showing the relationship between a pressure vessel, a stirring mechanism, and a discharge port when viewed from the top side of a subcritical water treatment apparatus 1 according to a first modified example. FIG. [Figure 12] 11 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to Modification 2. FIG. [Figure 13] FIG. 11 is a diagram showing the relationship between a pressure vessel, a stirring mechanism, and a discharge port when viewed from the top side of the subcritical water treatment apparatus according to Modification 2. [Figure 14] FIG. 11 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to Modification 3. [Figure 15] FIG. 11 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to a fourth modified example. [Figure 16] FIG. 13 is an enlarged view of a second agitating impeller according to Modification 4. [Figure 17] FIG. 13 is a diagram showing the relationship between a pressure vessel, a stirring mechanism, and a discharge port according to Modification 4. [Figure 18] 13 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to Modification 5. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic features shown in the following embodiments can be combined with each other. <Subcritical water treatment equipment> First, the subcritical water treatment apparatus of the present invention will be described.

[0010] Fig. 1 is a schematic diagram showing a partial cross section of an embodiment of a subcritical water treatment apparatus, and Fig. 2 is a plan view showing the configuration of a separator. The subcritical water treatment apparatus 1 of the present invention is a subcritical water treatment apparatus that performs subcritical water treatment on organic waste to obtain a treated product. Here, the subcritical water treatment is a method of contacting gaseous subcritical water with organic waste under high temperature and pressure, which is equal to or lower than the critical temperature of water and equal to or higher than the saturated water vapor pressure, to reduce the molecular weight of the organic waste. This reduction in molecular weight decomposes the organic waste to obtain a treated product.

[0011] Organic waste is waste that cannot be hydrolyzed by anaerobic or aerobic bacteria, and may include, for example, paper, cloth, clothing, plastics, rubber, leather, wood, bamboo, straw, kitchen waste, non-burnable materials, medical waste, and discarded packaged food, and may include one or more of these. 1 includes a pressure vessel 2 having a center line O21 along the horizontal direction, an agitation mechanism 3 that agitates the organic waste contained in the pressure vessel 2, and a heating mechanism 4 that heats the organic waste. In the following description, the circumferential direction means the direction around the center line O21, and the radial direction means the radial direction centered on the center line O21.

[0012] The pressure vessel 2 comprises a vessel body 21, an inlet 22 for introducing organic waste into the vessel body 21, an outlet 23 for discharging the treated material from within the vessel body 21, a liquid storage section 24, a separator 25, and a stand 29. The pressure vessel 2 of this embodiment is a horizontal pressure vessel supported by a stand 29 so that the center line O21 of the vessel body 21 is aligned horizontally.

[0013] The volume of container body 21 is preferably about 200 to 5000 L, more preferably about 250 to 4000 L, and further preferably about 300 to 3000 L. By using container body 21 with such a volume, it is possible to sufficiently miniaturize subcritical water treatment device 1 while sufficiently accommodating organic waste, and thus it is possible to meet the need for a large-capacity, space-saving subcritical water treatment device 1. As will be described later, the subcritical water treatment apparatus 1 can be housed in a container and transported in this state to a desired location.

[0014] The insertion port 22 has a cylindrical body 221, and is connected to the container body 21 so as to communicate with a through-hole 2113 formed in the upper part of the container body 21. The insertion port 22 also has a lid portion (clutch door) 223 that airtightly seals the opening 222 of the body 221. Furthermore, the input port 22 has pressure vessel valves 224 and 225. The pressure inside the pressure vessel 2 can be adjusted by opening and closing the pressure vessel valve 224 or 225. Note that the pressure vessel valve 224 or 225 does not need to be provided at the input port 22, and may be provided at another location in the pressure vessel 2.

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

[0016] In this pressure vessel 2, by opening the lid portion 223 while keeping the lid portion 233 closed, organic waste can be introduced into the vessel body 21 through the body portion 221 of the inlet 22. Thereafter, the lid portion 223 is closed and the organic waste is subjected to subcritical water treatment in the vessel body 21. The treated product produced by the subcritical water treatment of this organic waste can be removed from the vessel body 21 through the body portion 231 of the outlet 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, the work of discharging (removing) the material to be treated from inside the container body 21 can be easily performed.

[0017] The liquid storage section 24 is provided in the pressure vessel 2 and stores the liquid L used in 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 heating of the organic waste is started by the heating mechanism 4. As a result, gaseous subcritical water is produced from the liquid L stored in the liquid storage section 24, and by bringing this subcritical water into contact with the organic waste, the organic waste is broken down into smaller molecules. Here, the liquid L may contain water as a main component, and may also contain other components such as hydrogen peroxide and sodium hydroxide.

[0018] According to the subcritical water treatment device 1, since no high-pressure boiler is attached, the subcritical water treatment device 1 can be made compact. Therefore, the subcritical water treatment device 1 can be installed in a relatively small space. For this reason, if the subcritical water treatment device 1 is configured to be mobile as described below and placed adjacent to a convenience store in an urban area, it can easily perform subcritical water treatment on expired daily deliveries (mainly boxed lunches) that are to be discarded. In addition, since no high-pressure boiler is attached, the subcritical water treatment device 1 can be operated and controlled not only by a qualified boiler engineer but also by a cashier at a convenience store. Therefore, the subcritical water treatment device 1 is extremely easy to operate and convenient.

[0019] In this embodiment, a part of the inner space of the outlet 23 is configured to function as the liquid storage portion 24. This configuration makes it possible to prevent an increase in the number of parts of the pressure vessel 2 and to prevent the configuration of the pressure vessel 2 from becoming complicated. This contributes to the miniaturization of the subcritical water treatment apparatus 1. In addition, by changing the installation position of the outlet 23 or adjusting the inclination angle of the center line O23 of the outlet 23 relative to the center line O21 of the container body 21, the entire internal space of the outlet 23 can be made to function as the liquid storage section 24. Furthermore, the liquid storage section 24 may be configured independently of the outlet 23. Examples of such a configuration include a recess formed on the inner surface of the bottom side of the container body 21, a container fixed to the inner surface of the upper side of the container body 21 or a container suspended from the inner surface.

[0020] The separator 25 is provided at the boundary between the container body 21 and the discharge port 23. The separator 25 has a function of allowing the vapor of the liquid L to pass through but preventing the organic waste from passing through. This configuration makes it possible to prevent or suppress the organic waste from being mixed into the liquid L contained in the discharge port 23 (liquid storage section 24). That is, the subcritical water treatment device 1 can store the organic waste in the container body 21 in an isolated state isolated from the liquid L contained in the liquid storage section 24. The isolated state is ensured by the presence of the separator 25. On the other hand, the generated vapor of the liquid L (gaseous subcritical water) can be brought into sufficient contact with the organic waste, reliably promoting its decomposition into smaller molecules.

[0021] 2 is formed into a circular shape as a whole by fixing a plurality of fan-shaped plate materials 251 to each other at the center so that they can be expanded. A plurality of through holes 2511 are formed in each plate material 251, penetrating in the thickness direction. Liquid L is supplied to the inner space (liquid storage section 24) of outlet 23 via through holes 2511, and vapor of liquid L can move into container body 21 via through holes 2511. If the liquid storage section 24 is not provided inside the discharge port 23, the separator 25 does not need to be configured as shown in Fig. 2. In this case, it is sufficient for the separator 25 to be able to prevent the organic waste from passing through 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 a lower part of the container body 21. In this case, the container body 21 and the inner space of the outlet 23 can be heated efficiently with low power consumption. This allows the vapor (gaseous subcritical water) of the liquid L to be generated smoothly with low power consumption. The heating mechanism 4 can be configured, for example, by an alumina heater type, an oil heater type, a light heating (infrared) type, an IH heater type, or the like.

[0023] When there is a relatively large amount of space available, the subcritical water treatment device 1 may be configured to include an external or internal high-pressure boiler instead of the liquid storage unit 24. In this case, gaseous subcritical water or steam (hereinafter collectively referred to as high-temperature steam) is supplied to the container body 21 and the heating mechanism 4 from the high-pressure boiler. Fig. 3 is a conceptual diagram partially illustrating a subcritical water treatment apparatus equipped with an external high-pressure boiler. Components other than the heating mechanism 4, the vessel body 21, the outlet 23, and the steam supply pipes 41 and 42 are omitted in Fig. 3. The components omitted in Fig. 3 are the same as those in the case where the liquid storage section 24 is included.

[0024] When the subcritical water treatment apparatus 1 is equipped with a high-pressure boiler, the heating mechanism 4 has a hollow structure (a double structure consisting of the vessel body 21 and a jacket arranged at a distance from the vessel body 21). High-temperature steam is supplied into the vessel body 21 and the heating mechanism 4 through steam supply pipes 41 and 42 connected to the high-pressure boiler, respectively. When high-temperature steam is supplied into the heating mechanism 4 via 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 via 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, which will be described later, the inside of the container body 21 is filled with gaseous subcritical water. When the pressure vessel 2 is equipped with a high-pressure boiler instead of having the liquid storage portion 24, high-temperature steam is supplied from the high-pressure boiler into the vessel body 21, so that gaseous subcritical water can be generated in a short time after starting the subcritical water treatment apparatus 1. This makes it possible to shorten the time required for the entire subcritical water treatment.

[0025] The stirring mechanism 3 includes a rotating shaft 31, a plurality of stirring blades 32 (six in this embodiment), a motor 33, a belt , and a stand . The rotating shaft 31 is disposed along the center line O21 of the container body 21, with one end thereof penetrating the container body 21. A sealing structure (not shown) is provided at the portion where the rotating shaft 31 penetrates the container body 21, thereby maintaining the airtightness of the container body 21. The motor 33 is mounted on a stand 35. The rotating shaft of the motor 33 is connected to an end of the rotating shaft 31 protruding from the container body 21 via a belt 34. This allows the rotational force of the motor 33 to be transmitted to the rotating shaft 31. This rotating shaft 31 has six stirring blades 32 arranged at a distance from each other along the center line O21 (the longitudinal direction of the rotating shaft 31), and arranged at approximately equal intervals (approximately 180° intervals) around the circumferential direction of the rotating shaft 31.

[0026] Fig. 4 is an enlarged view of the stirring blade. Fig. 5 is a diagram showing the relationship between the pressure vessel 2 (vessel body 21), the stirring mechanism 3 (rotating shaft 31 and stirring blade 32), and the outlet 23 when viewed from the top side of the subcritical water treatment apparatus 1. Fig. 5 shows a cross section of a part of the subcritical water treatment apparatus 1. Also, Fig. 5 omits configuration other than the heating mechanism 4, vessel body 21, outlet 23, rotating shaft 31, and stirring blade 32. In Fig. 5, the stirring blade 32 located below the rotating shaft 31 is indicated by a dashed line. 1 and other figures, the multiple agitating blades 32 have the same shape. Each agitating blade 32 has a cylindrical blade shaft portion 321 and a blade portion 322 provided on the side of the blade shaft portion 321 opposite to the rotation shaft 31.

[0027] Each stirring blade 32 (blade shaft portion 321) protrudes radially outward from the rotation shaft 31 along an intersection line I that is substantially perpendicular to the center line O21 of the vessel body 21. In this embodiment, each wing portion 322 has two main surfaces (flat surfaces) 3221 and two side surfaces 3222 connecting the main surfaces 3221. The main surfaces 3221 are approximately parallel to the intersection line I and inclined at an inclination angle θ with respect to the center line O21 of the container body 21. That is, each stirring blade 32 has a main surface 3221 that is approximately parallel to the intersection line I and inclined with respect to the center line O21. The shape of the side surface 3222 is not particularly limited, but is flat in this embodiment and inclined at a predetermined inclination angle with respect to the center line O21 of the container body 21. In this embodiment, the angle between the main surface 3221 and the side surface 3222 is approximately 90°. The top surface of each wing portion 322 (the surface opposite to the blade shaft portion 321) is arc-shaped in accordance with 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] In the case of the subcritical water treatment apparatus 1 of the present embodiment, which has a horizontal pressure vessel 2 with a center line O21 aligned horizontally, it may be difficult to move the organic waste and treatment materials contained in the pressure vessel 2 in a direction along the center line O21. In this case, the organic waste cannot be sufficiently agitated, the opportunity for contact with gaseous subcritical water is reduced, and the treatment efficiency cannot be improved. Therefore, in the subcritical water treatment apparatus 1 of this embodiment, each agitator blade 32 is provided 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 rotates the rotating shaft 31, the main surface 3221 comes into contact with the organic waste in the container body 21, and the organic waste can be pushed and moved in a direction along the center line O21. As a result, the organic waste can be sufficiently agitated, and the treatment efficiency is improved.

[0029] Specifically, by rotating the rotating shaft 31 forward or backward by the motor 33, the organic waste can be moved and stirred not only vertically up and down but also in a direction along the center line O21 within the container body 21. Furthermore, after the organic waste is treated with subcritical water, the treated material that is generated can be moved to the vicinity of the discharge outlet 23, so that the treated material can be quickly discharged from the discharge outlet 23. Furthermore, since the agitating blades 32 are spaced apart from each other, the organic waste moving in the direction along the center line O21 can be thrown up vertically upward (scrambled up) and then dropped vertically downward between the agitating blades 32. This makes it possible to prevent the organic waste from moving more than necessary in the direction along the center line O21 when treating the organic waste with subcritical water. This makes it possible to prevent the rotating shaft 31 from frequently repeating forward and reverse rotation.

[0030] In this embodiment, all the agitating blades 32 have the same shape. In this case, it is expected that design costs, manufacturing costs, maintenance costs, etc. can be reduced compared to when the agitating blades 32 have different shapes. In addition, since all the agitating blades 32 have the same shape, two adjacent agitating blades 32 have main surfaces 3221 with substantially the same inclination angle θ with respect to the center line O21. This makes it easier to move the organic waste and materials to be treated in the container body 21 at a constant speed in the direction along the center line O21. This can improve the smoothness of moving the organic waste and materials to be treated.

[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°. With this configuration, when motor 33 rotates and drives rotary shaft 31, main surface 3221 can more easily push and move organic waste, further improving the efficiency of organic waste treatment. In addition, the treated material obtained by the subcritical water treatment can be more easily moved to the vicinity of discharge outlet 23, so that the treated material can be quickly discharged from discharge outlet 23.

[0032] Furthermore, for main surface 3221 with inclination angle θ of about 30 to 70°, the inclination angle θ with respect to center line O21 may be set to be larger for main surface 3221 closer to discharge outlet 23. In this case, the movement of the processing object in the direction along center line O21 can be suppressed closer to discharge outlet 23. Therefore, it can be expected that the processing object will be more likely to accumulate around discharge outlet 23 when discharged, and the processing object can be discharged from discharge outlet 23 more smoothly. Instead of gradually increasing the inclination angle θ toward the exhaust port 23, the inclination angle θ with respect to the center line O21 may be increased only for the main surface 3221 closer to the exhaust port 23.

[0033] Furthermore, for main surface 3221 with inclination angle θ of approximately 30 to 70°, the inclination angle θ with respect to center line O21 may be set to be smaller for main surface 3221 closer to inlet 22. In this case, the movement of the organic waste in the direction along center line O21 may be promoted closer to inlet 22. This is expected to prevent organic waste introduced through inlet 22 from remaining around inlet 22, enabling smooth subcritical water treatment. Instead of gradually decreasing the inclination angle θ toward the insertion opening 22, the inclination angle θ with respect to the center line O21 may be decreased only for the main surface 3221 close to the insertion opening 22.

[0034] Furthermore, in this embodiment, since steam is supplied from the separator 25, there is a possibility that a large amount of highly active gaseous subcritical water is present near the separator 25. Therefore, for the main surfaces 3221 having an inclination angle θ of about 30 to 70°, the inclination angle θ with respect to the center line O21 may be set to be smaller for the main surfaces 3221 closer to the separator 25. This suppresses movement of the organic waste in the direction along the center line O21 in areas where a large amount of highly active gaseous subcritical water is present, and therefore the efficiency of the subcritical water treatment can be improved.

[0035] Furthermore, when the maximum length of the main surface 3221 in the direction perpendicular to the intersection line I is X [mm] and the diameter of the container body 21 is Y [mm], it is preferable that X / Y is about 0.2 to 0.5, and more preferably about 0.25 to 0.45. By configuring in this way, it is possible to ensure a sufficient 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 stirred up by the agitating blades 32 vertically downward between the adjacent agitating 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 efficiency of treating the organic waste can be further improved. For example, in the case of a container body 21 with a volume of 3000 L, X / Y is preferably set to about 0.35, and in the case of a container body 21 with a volume of 400 L, X / Y is preferably set to about 0.34.

[0036] In addition, in the mixing impeller 32, the blade shaft portion 321 and the blade portion 322 may be formed integrally, or may be formed as separate bodies and connected to each other. In the latter case, the blade portion 322 can be replaced with a blade portion 322 having a different shape. The shapes of the stirring blades 32 do not need to be the same, and may be different from each other. For example, a plurality of sets of stirring blades having different shapes may be provided. The shape of the impeller 32 may be configured to have different functions depending on the installation position. For example, the impeller 32 in the center may be configured to have a shape that makes it easy to move organic waste in the direction along the center line O21, and the impeller 32 at the end may be configured to have a shape that makes it easy to scrape out 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 that the stirring blade 32 has is not limited to two, and may be one, or three or more. Furthermore, 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 semicircle, or the like. An example in which the number and shape of the main surfaces are different from those of this embodiment will be described in detail in Modification 4.

[0038] The shape of the blade shaft portion 321 is not limited to a cylindrical shape, and may be, for example, a truncated cone shape, a square prism shape, or the like. Furthermore, the number of stirring blades 32 to be installed is not limited to six, but may be two, three, four, seven or more. Furthermore, the installation intervals of the stirring blades 32 are not limited to 180° intervals along the circumferential direction of the rotating shaft 31, but may be, for example, 60° intervals, 90° intervals, 120° intervals, or 210° intervals along the circumferential direction.

[0039] Furthermore, the installation intervals of the stirring blades 32 along the circumferential direction of the rotating shaft 31 may be non-uniform along the center line O21. For example, the stirring blades 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 installed at 180° intervals along the circumferential direction of the rotating shaft 31 at the center. Furthermore, a plurality of agitating blades 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, a plurality of agitating blades 32 may be located on the same circumference of the rotating shaft 31. For example, a plurality of agitating blades 32 may be provided on the same circumference of the rotating shaft 31 in a location where the organic waste and the material to be treated are likely to accumulate (for example, an end of the container body 21). An example in which the intervals between the agitating blades 32 are not uniform and a plurality of the agitating blades 32 are provided on the same circumference of the rotating shaft 31 will be described in detail in the fifth modification.

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

[0041] In S101, with lid 233 of outlet 23 closed, lid 223 of inlet 22 is opened, and liquid L is introduced into liquid storage section 24 through opening 222 and through-hole 2113. From this liquid L, vapor of liquid L (gaseous subcritical water) required for subcritical water treatment is obtained. Next, in S102, organic waste is poured into the container body 21 through the opening 222 and the through-hole 2113. After the organic waste has been poured in, the lid 223 is closed. When the lid 223 is closed, the pressure vessel 2 is put into a sealed state.

[0042] In S103, the heating mechanism 4 is activated to heat the inside of the container body 21. When the heat of the container body 21 is transferred to the liquid storage portion 24, steam is generated from the liquid L in the liquid storage portion 24. When this steam is supplied into the container body 21 through the through-hole 2511 of the separator 25, the pressure inside the pressure vessel 2 in the sealed state increases. Furthermore, the motor 33 is started to rotate the rotary shaft 31. That is, the agitation mechanism 3 is started to start agitating the organic waste.

[0043] At this time, as described above, the main surface 3221 pushes in the organic waste by rotating the rotating shaft 31 in the normal or reverse direction by the motor 33, and the organic waste can be moved in a direction along the center line O21. During this movement, the organic waste is stirred up vertically upward by the agitating blades 32, and the organic waste is dropped vertically downward between the plurality of agitating blades 32 that are spaced apart from one another. This makes it possible to prevent unnecessary movement of the organic waste, and therefore to reduce the number of times that the rotating shaft 31 is rotated in the normal and reverse directions by the motor 33. Therefore, subcritical water treatment can be performed with reduced power consumption.

[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, and if both the pressure and the temperature have reached the specified values, the process proceeds to S105. The specified values ​​of pressure and temperature that are the basis of the judgment in S104 are the values ​​of temperature and pressure required for the subcritical water treatment, and will be described later.

[0045] In S105, it is confirmed whether a certain period of time has passed. If the certain period of time has not passed, the process remains in S105, and if the certain period of time has passed, the process proceeds to S106. The time used as the criterion for the judgment in S105 is the time required for the subcritical water treatment, which will be described later. As described above, the subcritical water treatment apparatus 1 of this embodiment has the main surface 3221 inclined with respect to the center line O21 and has a plurality of stirring blades 32 spaced apart from one another, so that the subcritical water treatment can be efficiently performed while moving the organic waste not only vertically but also in the direction along the center line O21 at an appropriate speed (i.e., while stirring sufficiently). This is expected to shorten the time required for the subcritical water treatment.

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

[0047] In S108, lid 233 of discharge outlet 23 is opened, and the treated material is removed from container body 21. When removing the treated material, rotating shaft 31 is rotated, causing stirring blades 32 to move the treated material to the vicinity of discharge outlet 23. After the discharge of the treated material is completed, stirring mechanism 3 is stopped, thereby ending this subcritical water treatment.

[0048] Fig. 7 is a flow chart showing the flow of subcritical water treatment in the case where the subcritical water treatment apparatus 1 has a high-pressure boiler instead of the liquid storage unit 24. 7 are similar to S102, S104 to S105, and S107 to S108 described with reference to FIG. 6, respectively, and therefore will not be described again. In S202, the high-pressure boiler is started up, and high-temperature steam is supplied from the high-pressure boiler to generate gaseous subcritical water required for the subcritical water treatment.

[0049] In S203, high-temperature steam from the high-pressure boiler is supplied into the heating mechanism 4 and the container body 21 via the steam supply pipes 41 and 42, respectively. At this time, high-temperature steam is supplied into the heating mechanism 4 via the steam supply pipe 41 first. 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 inside the container body 21. Also, in S203, the stirring mechanism 3 is started in the same way as in S103 of Fig. 6, to start stirring the organic waste.

[0050] In S206, when the necessary time has elapsed under the temperature and pressure required for the subcritical water treatment, the high-pressure boiler is stopped. Also, the pressure vessel valve 224 or 225 is slightly opened. That is, the pressure inside the pressure vessel 2 is reduced while the temperature is lowered. According to the flow described above, subcritical water treatment can be performed using the subcritical water treatment apparatus 1 of this embodiment. After S106 and S206, the heating of the treated material by the heating mechanism 4 may be continued (in the case of S206, the supply of high-temperature steam to the heating mechanism 4 is continued). This makes it possible to reduce (adjust) the moisture content of the treated material. Such a process is effective when the treated material is used for producing pellets for fuel use as described below.

[0051] 6, the amount of liquid L used in the subcritical water treatment is not particularly limited, but is preferably about 0.001 to 0.1 times, and more preferably about 0.005 to 0.05 times, the volume of the container body 21. If such an amount of liquid L is used, gaseous subcritical water sufficient to break down organic waste into smaller molecules can be generated. The temperature of the gaseous subcritical water (vapor of liquid L) is preferably about 150 to 230° C., and more preferably about 160 to 220° C. The pressure is preferably about 15 to 25 atm, and more preferably about 18 to 22 atm. The specific temperature and pressure of the gaseous subcritical water are preferably about 200° C. and about 20 atmospheres.

[0052] The rotational circumferential speed of the radially outer end of the agitator blade 32 is preferably 2 m / sec or more, and more preferably 3 m / sec or more. The upper limit of the rotational circumferential speed is usually about 7 m / sec. At such a rotational circumferential speed, the organic waste can be moved at an appropriate speed in the direction along the center line O21, and the use of a high-output, expensive motor 33 can be avoided. The time for the subcritical water treatment is appropriately set depending on the type of organic waste, and is not particularly limited, but is preferably about 0.1 to 10 hours, and more preferably about 0.5 to 5 hours.

[0053] This subcritical water has a dielectric constant of 15 to 45, which is equivalent to the dielectric constant of low-polarity solvents. Therefore, it can dissolve many organic substances. Furthermore, subcritical water has an ion product of 1×10 -12 ~1×10 -11 Mol 2 / kg 2 The proportion of hydrogen ions that separate into hydrogen ions and hydroxide ions is high, and therefore the hydrogen ions exhibit a strong hydrolysis effect. The dielectric constant of water at room temperature and atmospheric pressure is about 80, and the ionic product of water at a temperature of about 25°C and atmospheric pressure is 1 x 10 -14 Mol 2 / kg 2 It is.

[0054] The organic waste that has been reduced in molecular weight (ie, the treated material) preferably has a solubilization rate of 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 the total organic matter after the subcritical water treatment, and a higher value indicates that the organic matter has been broken down into smaller molecular weight substances. Specific examples of low molecular weight substances obtained by breaking down organic waste include carbohydrates, proteins, fats, etc., which are broken down into their corresponding sugars, amino acids, higher fatty acids, etc. Moreover, the subcritical water treatment in the subcritical water treatment apparatus 1 is a batch treatment by its nature, but 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 a subcritical water treatment unit. The subcritical water treatment unit 100 shown in FIG. 8 includes the subcritical water treatment apparatus 1 and a pelletizer / semi-carbonizer 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-carbonization device that semi-carbonizes the pellet raw material containing the material to be treated, and then pelletized by a pelletizing device, or vice versa. Here, the pelletizing device is a device that pelletizes the pellet raw material or the semi-carbonized pellet raw material to obtain pellets.

[0055] The pelletizer / semi-carbonizer 10 may include a mixer (not shown) for mixing the material to be treated with woody biomass and obtaining the mixture as pellet raw material, as necessary. The composition of organic waste varies depending on the region and time of collection, and the calorific value of the treated material obtained by subcritical water treatment also varies. In order to compensate for (adjust) this fluctuation in calorific value, woody biomass can be mixed with the treated material. This makes it possible to produce pellets (solid fuel) in an extremely short time with a stable calorific value equivalent to that of coal and with a quality equivalent to the quality classification for the total chlorine mass fraction specified by the RPF.

[0056] Examples of woody biomass that can be used in the present invention include the ends (so-called "offcuts") that are generated when logs cut from the mountains are processed into lumber (boards, posts, etc.), crushed log bark, and waste paper made from wood. The resulting pellets will generate CO2 when burned, but woody biomass is carbon neutral because it simply returns the CO2 absorbed by the trees in the forest back into the atmosphere. Therefore, for example, a "biomass energy fuel" such as the pellets obtained in this embodiment can be said to be an ecological fuel.

[0057] The size, shape, etc. of the resulting pellets are not particularly limited as long as they can be suitably used as fuel for the intended device. Furthermore, the pellets obtained by semi-carbonization are composed of highly pure carbonized material with a reduced moisture content and volatile organic component content, and therefore have an increased calorific value and excellent durability and storage stability in the natural environment.

[0058] The semi-carbonization process using the semi-carbonization apparatus is carried out by subjecting the pellet raw material to a heat treatment in an atmosphere with a low oxygen concentration. The heat treatment temperature is preferably about 200 to 700° C., and more preferably about 200 to 300° C. The heat treatment time is preferably about 1 to 24 hours, and more preferably about 1 to 3 hours. By carrying out the semi-carbonization treatment under such conditions, the pellet raw material can be reliably semi-carbonized. Here, the semi-carbonized state refers to a state in which about half of the pellet raw material is converted into carbide.

[0059] As the pelletizing device, for example, a strand type extruder, a hot cut type extruder, or the like can be used. As shown in FIG. 8, the subcritical water treatment unit 100 of this embodiment has a container 200 that can be transported while accommodating the subcritical water treatment device 1 and the pelletizing device / semi-carbonizing device 10 therein. The container 200, housing the subcritical water treatment device 1 and the pelletizing device / semi-carbonizing device 10, is loaded onto a large vehicle 300. This allows the subcritical water treatment unit 100 to be moved to a predetermined location depending on the purpose.

[0060] The volume of the container 200 is 10 to 70 m 3 It is preferable that the distance is about 15 to 65 m. 3 It is more preferable that the distance is about 20 to 50 m. 3 It is even more preferable that the container 200 is about this size. It is easy to secure a place to install the container 200 even in an urban area.

[0061] Furthermore, the subcritical water treatment unit 100 may have a water treatment device / deodorization treatment device in place of the pelletizing device / semi-carbonizing device 10 or in combination with the pelletizing device / semi-carbonizing device 10 depending on the purpose. 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 standards of the water treatment. This water treatment device can be configured, for example, as a device that performs a 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 configured, for example, as an adsorption filter device.

[0062] The gas discharged from the subcritical water treatment device 1 may be subjected to water treatment by a water treatment device and then deodorized by a deodorization treatment device, or vice versa. The subcritical water treatment unit 100 may include the subcritical water treatment device 1 and at least one of a pelletizing device, a semi-carbonizing device, a water treatment device, and a deodorizing device. In this case, the container 200 accommodates the subcritical water treatment device 1 and the at least one of the devices. Therefore, the multiple devices constituting the subcritical water treatment unit 100 may all be housed in one container 200, or may be housed separately in multiple containers 200, depending on the volume (size) of the container 200, the volume of the vessel body 21, whether a high-pressure boiler is attached, etc. In the latter case, the volumes of the multiple containers 200 may be the same or different.

[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 improve the treatment efficiency.

[0064] <Modification> Hereinafter, each modification of the subcritical water treatment apparatus 1 of this embodiment will be described. In each drawing, the same members as those in the above configuration example (see FIG. 1, etc.) are given the same reference numerals. Further, each modified example of the subcritical water treatment apparatus 1 will be described, but the differences from the above-described configuration example will be mainly described, and a description of the similar points will be omitted.

[0065] (Variation 1) Fig. 9 is a conceptual diagram showing a partial cross section of the subcritical water treatment apparatus according to Modification 1. In Fig. 9, outlet 23 is indicated by a dashed line. Fig. 10 is a conceptual diagram showing a partial cross section of the subcritical water treatment apparatus according to Modification 1 as viewed from the side (the right side in Fig. 9). In Fig. 10, components other than heating mechanism 4, container body 21, inlet 22, outlet 23, liquid storage unit 24, and stand 29 are omitted. Fig. 11 is a diagram showing the relationship between the pressure vessel, the stirring mechanism, and the outlet when viewed from the top side of the subcritical water treatment apparatus 1 according to Modification 1. Fig. 11 shows a cross section of a part of the subcritical water treatment apparatus 1. Also, Fig. 11 omits configuration other than the heating mechanism 4, the vessel body 21, the outlet 23, the rotating shaft 31, and the stirring blades 32. In Fig. 11, the stirring blades 32 located below the rotating shaft 31 are indicated by dashed lines.

[0066] In the first modification of the subcritical water treatment apparatus 1, the configuration of the vessel body 21 and the configuration of the stirring mechanism 3 are different, but the rest is the same as the above-described configuration example. That is, as shown in Fig. 9 and Fig. 10, in the subcritical water treatment apparatus 1 according to the first modification, the outlet 23 is located at the center of the vessel body 21 in the direction along the center line O21. Also, as shown in Fig. 9 and Fig. 11, the impeller 32 arranged on the right side of the outlet 23 (one side along the center line O21) has a shape that is symmetrical with respect to the impeller 32 arranged on the left side (the other side). Therefore, the inclination direction of the main surface (flat surface) 3221 arranged on the right side of the outlet 23 (one side along the center line O21) is opposite to the inclination direction of the main surface (flat surface) 3221 arranged on the left side (the other side).

[0067] When the rotating shaft 31 is rotated in one direction after the subcritical water treatment, the main surface 3221 arranged on the right side of the discharge outlet 23 and the main surface 3221 arranged on the left side push the treated material in the left-right opposite directions. Therefore, by rotating the rotating shaft 31 in one direction, the treated material located on the right side of the discharge outlet 23 can be moved to the left, and the treated material located on the left side of the discharge outlet 23 can be moved to the right. As a result, even if the discharge outlet 23 is located in the center of the subcritical water treatment device 1, the treated material can be moved to the vicinity of the discharge outlet 23 by rotating the motor 33 in one direction. Therefore, the treated material can be discharged from the discharge outlet 23 quickly and with low power consumption.

[0068] In this first modification, as long as the main surface 3221 is inclined in opposite directions on the left and right sides of the discharge port 23, the agitating blade 32 does not need to have an axisymmetric shape on the left and right sides of the discharge port 23. In addition, in this modified example 1, the discharge port 23 does not need to be located in the center along the center line O21 of the container body 21, and may be offset toward one end from the center. 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 body 21. In this case, it is also sufficient that the agitator 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] (Variation 2) Fig. 12 is a conceptual diagram showing a partial cross section of the subcritical water treatment apparatus according to Modification 2. Fig. 13 is a diagram showing the relationship between the pressure vessel, the stirring mechanism, and the outlet when viewed from the top side of the subcritical water treatment apparatus according to Modification 2. Fig. 13 shows a part of the subcritical water treatment apparatus 1 in cross section. Also, Fig. 13 omits configuration other than the heating mechanism 4, the vessel body 21, the outlet 23, the rotating shaft 31, and the stirring blades 32. In Fig. 13, the stirring blades 32 located below the rotating shaft 31 are indicated by dashed lines.

[0070] In the second modification of the subcritical water treatment apparatus 1, the configuration of the vessel body 21 and the configuration of the stirring mechanism 3 are different, but the rest is the same as the above-described configuration example. That is, as shown in Fig. 12, in the subcritical water treatment apparatus 1 according to the second modification, the outlets 23 are disposed at both ends in the direction along the center line O21 of the vessel body 21 of the pressure vessel 2. Also, as shown in Fig. 12 and Fig. 13, the impeller 32 disposed on the right side of the center line C in the direction along the center line O21 of the vessel body 21 has a shape that is symmetrical with respect to the impeller 32 disposed 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] In this way, since the inclination directions of the main surface 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 treated material in the opposite left and right directions. Therefore, by rotating the rotating shaft 31 in one direction, the treated material located on the right side of the center line C can be moved to the right, and the treated material located on the left side of the center line C can be moved to the left. Therefore, when the treated material is discharged from the discharge outlet 23, by rotating the rotating shaft 31 in one direction, the treated material can be moved to the vicinity of the discharge outlet 23 that is closer to the treated material. As a result, even if the discharge outlet 23 is located at both ends of the subcritical water treatment device 1, the treated material can be discharged from the discharge outlet 23 quickly and with less power consumption.

[0072] In addition, since the discharge outlets 23 are provided at both ends, the movement of the treated material in the direction along the center line O21 can be shortened, and the amount of the treated material discharged from each discharge outlet 23 can be reduced. Therefore, the treated material can be discharged from the discharge outlets 23 in a short time. As a result, the subcritical water treatment of the next batch can be started smoothly. In addition, not only a plurality of discharge ports 23 but also a plurality of input ports 22 may be provided. In addition, in this modified example 2, as long as the main surface 3221 is inclined in opposite directions on the right and left sides of the center line C, the stirring blade 32 does not need to have a shape that is line-symmetrical on the left and right sides of the center line C.

[0073] (Variation 3) FIG. 14 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to the third modification. In the third modification of the subcritical water treatment apparatus 1, the configuration of the vessel body 21 is different, but the rest is the same as the above-described configuration example. That is, in the subcritical water treatment apparatus 1 according to the third modification, the inlet 22 is disposed at the left end of the vessel body 21, that is, at the end opposite to the outlet .

[0074] When the rotating shaft 31 is rotated so that the main surface 3221 moves the organic waste to the right, the organic waste inserted through the inlet 22 moves from the left end of the container body 21 to near the outlet 23 located at the right end. In this way, by performing subcritical water treatment while moving the organic waste by making maximum use of the length of the container body 21 in the direction along the center line O21, sufficient subcritical water treatment can be performed from the time the organic waste is charged into the charge port 22 until it reaches the discharge port 23. In this case, subcritical water treatment can be performed by rotating the rotating shaft 31 in one direction from the time the stirring mechanism 3 is started in S103 of Fig. 6 (or S203 of Fig. 7) until the stirring mechanism 3 is stopped in S108 of Fig. 6 (or S208 of Fig. 7).

[0075] In other words, subcritical water treatment can be carried out by simply rotating the rotating shaft 31 in the same direction from the time when the organic waste is fed through the feed inlet 22 until the treated waste is discharged from the discharge outlet 23. Therefore, in the subcritical water treatment apparatus 1 according to the third modification, power consumption caused by switching between forward and reverse rotation of the rotating shaft 31 can be suppressed. Of course, the organic waste may be agitated by rotating the rotating shaft 31 in both forward and reverse directions, depending on the length of the container body 21 in the direction along the center line O21, the type and amount of organic waste, temperature and pressure conditions, etc.

[0076] (Variation 4) FIG. 15 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to the fourth modification. In the fourth modification of the subcritical water treatment apparatus 1, the configuration of the stirring mechanism 3 is different, but the rest is the same as the above-described configuration example. That is, the stirring mechanism 3 of the modified example 4 has stirring blades of two different shapes. Here, the stirring blade having a shape different from the stirring blade 32 described above is called the second stirring blade 36. In the modified example 4, the two second stirring blades 36 are arranged on both sides of the multiple stirring blades 32 (four in this modified example) in the direction along the center line O21.

[0077] Fig. 16 is an enlarged view of the second agitating impeller according to Modification 4. Fig. 17 is a view showing the relationship between the pressure vessel, the agitating mechanism, and the outlet according to Modification 4. Fig. 17 shows the relationship when viewed from the top side of the subcritical water treatment device, and shows a cross section of a part of the subcritical water treatment device. In Fig. 17, configurations other than the heating mechanism 4, the vessel body 21, the outlet 23, the rotating shaft 31, the agitating impeller 32, and the second agitating impeller 36 are omitted. In Fig. 17, the agitating impeller 32 and the second agitating impeller 36 located below the rotating shaft 31 are shown by dashed lines.

[0078] The second agitating blade 36 does not have a boundary between the blade portion and the blade shaft portion. The second agitating blade 36 protrudes radially outward from the rotating shaft 31 along the intersection line I2 that is approximately perpendicular to the center line O21 of the container body 21. Each second agitating blade 36 has one main surface (flat surface) 361 as a surface facing inward in the direction along the center line O21. The main surface 361 is configured to be approximately parallel to the intersection line I2 and to form an inclination angle θ2 with the center line O21 of the container body 21. That is, the second agitating blade 36 has a main surface 361 that is approximately parallel to 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 agitating 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. Therefore, the second agitating blades 36 located at both ends of the multiple agitating blades 32 in the direction along the center line O21 can be arranged closer to the inner surface of the container body 21. Therefore, the main surface 361 can push and move the organic waste and treated materials that have moved to the end of the container body 21 in the direction along the center line O21, so that the organic waste and treated materials can be prevented from accumulating at the end of the container body 21. (Variation 5) FIG. 18 is a conceptual diagram showing a partial cross section of a subcritical water treatment apparatus according to the fifth modification. In the fifth modification of the subcritical water treatment apparatus 1, the configuration of the stirring mechanism 3 is different, but the rest is the same as the above-described configuration example. That is, in the stirring mechanism 3 of the modified example 5, the installation intervals of the stirring blades 32 are not uniform.

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

[0081] Meanwhile, one stirring blade 32 is provided on the same circumference of the rotation shaft at each of the second, fourth, fifth, sixth, and seventh farthest positions (positions 2, 4, 5, 6, and 7) from the discharge port 23. The stirring blades 32 arranged at adjacent positions are provided at intervals of approximately 90°.

[0082] At the first and third positions near the end of the container body 21 opposite the discharge outlet 23, a plurality of stirring blades 32 are provided on the same circumference of the rotating shaft 31, so that the organic waste or the treated material is easily pushed in the direction along the center line O21 by the main surface 3221. As a result, the organic waste or the treated material is sufficiently stirred in the direction along the center line O21 without being retained even at the end, improving the efficiency of the subcritical water treatment.

[0083] At the second position, which is between the first and third positions, only one agitator blade 32 is provided on the same circumference of the rotating shaft 31, so that the organic waste stirred up vertically upward by the main surface 3221 of the agitator blade 32 at the first and third positions tends to fall vertically downward at the second position. This makes it possible to prevent the organic waste from being moved too far in the direction along the center line O21, thereby suppressing power consumption caused by repeated forward and reverse rotation of the rotating shaft 31.

[0084] At each of the fourth and fifth positions located in the center along the center line O21 of the container body 21, only one agitator blade 32 is provided on the same circumference of the rotating shaft 31, so that the organic waste stirred up vertically upward by the main surface 3221 of the agitator blade 32 tends to fall vertically downward. This makes it possible to prevent the organic waste from moving too far in the direction along the center line O21 in the center of the container body 21 where the organic waste is unlikely to accumulate, thereby suppressing power consumption caused by repeated forward and reverse rotation of the rotating shaft 31.

[0085] At each of the sixth and seventh positions close to the discharge port 23, only one agitator blade 32 is provided on the same circumference of the rotating shaft 31, so that the treated material stirred up vertically upward by the main surface 3221 of the agitator blade 32 is likely to fall vertically downward. This makes it easier for the treated material to remain near the discharge port 23 when it is discharged from the discharge port 23, so that it is expected that the treated material can be discharged in a short time. As a result, the subcritical water treatment of the next batch can be started smoothly, improving the efficiency of the subcritical water treatment.

[0086] According to the above-mentioned configuration, the organic waste can be subjected to subcritical water treatment while being moved at an appropriate speed, and the efficiency of treating the organic waste can be improved. Furthermore, it may be provided in the following aspects:

[0087] (1) A subcritical water treatment apparatus for treating organic waste with subcritical water to obtain a treated product, the subcritical water treatment apparatus comprising: a pressure vessel having a center line along a horizontal direction; an agitation mechanism for agitating the organic waste contained in the pressure vessel; and a heating mechanism for heating the organic waste, the pressure vessel comprising a vessel body, an inlet for feeding the organic waste into the vessel body, and an outlet for discharging the treated product from within the vessel body, the agitation mechanism comprising a rotating shaft disposed along the center line, and a plurality of agitation blades spaced apart from one another and protruding radially outward from the rotating shaft along an intersection line substantially perpendicular to the center line, each of the agitation blades having a flat surface substantially parallel to the intersection line and inclined with respect to the center line.

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

[0089] (3) The subcritical water treatment apparatus according to (2) above, wherein the flat surface closer to the outlet has a larger inclination angle with respect to the center line.

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

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

[0092] (6) The subcritical water treatment device according to any one of (1) to (5) above, wherein the outlet is located at a center of the container body in a direction along the center line, and the inclination direction of the flat surface located on one side of the outlet along the center line is opposite to the inclination direction of the flat surface located on the other side.

[0093] (7) The subcritical water treatment apparatus according to any one of the above (1) to (6), wherein two adjacent stirring blades have flat surfaces that are inclined at approximately the same angle with respect to the center line.

[0094] (8) The subcritical water treatment apparatus according to any one of (1) to (7) above, wherein the rotation shaft is rotated in only one direction from the time the organic waste is fed through the inlet until the treated material is discharged through the outlet.

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

[0096] (10) A subcritical water treatment unit comprising: a subcritical water treatment device according to any one of (1) to (9) above; a semi-carbonization device for semi-carbonizing a pellet raw material containing the treatment product; a pelletizing device for pelletizing the pellet raw material or the semi-carbonized pellet raw material to obtain pellets; at least one of a water treatment device for water treating a gas discharged from the subcritical water treatment device and a deodorization treatment device for deodorizing the gas discharged from the subcritical water treatment device; and a container capable of transporting the subcritical water treatment device and the at least one device housed therein.

[0097] (11) In the subcritical water treatment unit described in (10) above, the volume of the container is 10 to 70 m 3 This is a subcritical water treatment unit. Of course, this is not the case.

[0098] Finally, although various embodiments of 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, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications are included within the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0099] 1: Subcritical water treatment equipment 2: Pressure vessel 21: Container body 2113:Through hole 2123:Through hole 22: Inlet 221: Torso 222 :Aperture 223: Lid 224: Pressure vessel valves 225: Pressure vessel valves 23: Outlet 231: Torso 232 :Aperture 233: Lid 24: Liquid storage section 25: Separation plate 251: Plate material 2511:Through hole 29: Stand 3: Mixing mechanism 31: Rotation axis 32: Mixing blade 321: Wing shaft section 322: Wing part 3221: Principal surface (flat surface) 3222: Side 33: Motor 34: Belt 35: Stand 36: Second mixing blade 361: Principal surface (flat surface) 362 :Outer part 4:Heating mechanism 41: Steam supply pipe 42: Steam supply pipe 10: Pelletizing equipment / semi-carbonizing equipment 100: Subcritical water treatment unit 200: Container 300: Large vehicles C: Chuo line I: Intersection line I2: Intersection 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, The present invention relates to a pressure vessel having a centerline along a horizontal direction, a stirring mechanism for stirring the organic waste contained 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 material from the vessel body, The stirring mechanism includes a rotating shaft arranged along the center line, and a plurality of stirring blades that protrude radially outward from the rotating shaft along an intersection line that is substantially perpendicular to the center line and are spaced apart from each other. Each of the agitating blades has a flat surface that is approximately parallel to the intersection line and inclined with respect to the center line.

2. The subcritical water treatment apparatus according to claim 1, The inclination angle of the flat surface with respect to the center line is 30 to 70 degrees.

3. The subcritical water treatment apparatus according to claim 2, The subcritical water treatment device, wherein the flat surface closer to the discharge port has a larger inclination angle with respect to the center line.

4. The subcritical water treatment apparatus according to claim 2, The subcritical water treatment device, wherein the flat surface closer to the inlet has a smaller inclination angle with respect to the center line.

5. The subcritical water treatment apparatus according to claim 1, the maximum length of the flat surface in a direction perpendicular to the line of intersection is X [mm], and the diameter of the container body is Y [mm], where X / Y is 0.2 to 0.

5.

6. The subcritical water treatment apparatus according to claim 1, The outlet is located at a center portion of the container body in a direction along the center line, a direction of inclination of the flat surface located on one side of the outlet along the center line is opposite to a direction of inclination of the flat surface located on the other side of the outlet.

7. The subcritical water treatment apparatus according to claim 1, The subcritical water treatment device, wherein two adjacent mixing blades have flat surfaces that are inclined at approximately the same angle with respect to the center line.

8. The subcritical water treatment apparatus according to claim 1, The subcritical water treatment apparatus rotates the rotation shaft only in the same direction from the time when the organic waste is fed through the feed port until the treated material is discharged through the discharge port.

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

10. 1. A subcritical water treatment unit comprising: The subcritical water treatment apparatus according to any one of claims 1 to 9, At least one of a semi-carbonization device that semi-carbonizes the pellet raw material including the treated material, a pelletization device that pelletizes the pellet raw material or the semi-carbonized pellet raw material to obtain pellets, a water treatment device that water treats the gas discharged from the subcritical water treatment device, and a deodorization treatment device that deodorizes the gas discharged from the subcritical water treatment device; A subcritical water treatment unit comprising the subcritical water treatment apparatus and a container capable of being transported while accommodating the at least one apparatus.

11. 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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