Fluidized medium recovery method and fluidized bed furnace equipment

Abstract

To provide: a fluid medium recovery method capable of efficiently recovering valuable metal from a fluid medium stored in the furnace body while continuing the operation of a fluidized bed furnace; and a fluidized bed furnace facility.SOLUTION: There is provided a fluid medium recovery method of recovering a fluid medium 13 from a fluidized bed furnace facility 1. The fluidized bed facility 1 comprises: a fluidized bed furnace 10 that comprises a furnace body 12 storing the fluid medium 13 and a discharge port 16a capable of discharging the fluid medium 13 from the furnace body 12, and incinerates or gasifies a processing object including valuable metal; a circulation passage 40 circulating the fluid medium 13 discharged from the discharge port 16a to the furnace body 12; and a storage container 50 disposed on the circulation passage 40 to store the fluid medium 13. The fluid medium recovery method includes: a circulation step of circulating the fluid medium 13 to the circulation passage 40; and a recovery step of recovering the fluid medium 13 from the storage container 50.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for recovering a fluid medium in a fluidized bed furnace facility and a fluidized bed furnace facility.

Background Art

[0002] In a fluidized bed furnace facility equipped with a fluidized bed furnace, a method of separating valuable metals from a fluid medium withdrawn from the fluidized bed furnace is known. For example, Patent Document 1 discloses a fluidized bed furnace facility (referred to as "waste treatment facility" in the document) including a fluidized bed furnace (referred to as "fluidized bed type gasification furnace" in the document), a circulation path (referred to as "return flow path" in the document), a classification unit, and a specific gravity separation unit. The classification unit and the specific gravity separation unit are arranged in order in the middle of the circulation path. The fluidized bed furnace has a discharge port capable of discharging a fluid medium containing incombustibles such as metal on the furnace bottom plate. The classification unit separates incombustibles from the fluid medium discharged from the discharge port. The specific gravity separation unit separates valuable metals from the fluid medium from which incombustibles have been separated by the classification unit. The fluid medium separated from the valuable metals by the specific gravity separation unit is returned to the fluidized bed furnace by the circulation path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, in the fluidized bed furnace facility described in Patent Document 1, the fluid medium withdrawn from the furnace bottom of the fluidized bed furnace is returned to the fluidized bed furnace after being separated from valuable metals by the specific gravity separation unit arranged in the middle of the circulation path. Here, it takes time to separate a large amount of valuable metals from the fluid medium in the specific gravity separation unit. Therefore, there is room for improvement in separating and recovering valuable metals from the fluid medium while continuing the operation of the fluidized bed furnace that circulates the fluid medium discharged from the fluidized bed furnace separated from valuable metals back to the fluidized bed furnace.

[0005] The present invention has been made in view of the above problems, and its objective is to provide a fluidized medium recovery method and fluidized bed furnace equipment that can efficiently recover valuable metals from a fluidized medium even while continuing to operate the fluidized bed furnace. [Means for solving the problem]

[0006] The characteristic of the fluidized medium recovery method according to the present invention is that it is a fluidized medium recovery method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container. fruit, The recovery process includes a measurement process for measuring the amount of the valuable metal contained in the fluid medium. It's at a single point.

[0007] According to this method, in the circulation process, the fluidized medium discharged from the outlet of the fluidized bed furnace is circulated through a circulation path, and a portion of the fluidized medium circulating through the circulation path is stored in a storage container provided in the circulation path. As a result, the fluidized medium discharged from the outlet is circulated through the circulation path and returned to the fluidized bed furnace, while valuable metals can be recovered from the fluidized medium stored in the storage container. In other words, valuable metals can be recovered by taking the fluidized medium from the storage container while continuing to operate the fluidized bed furnace. As a result, the operating efficiency of the fluidized bed furnace can be increased, and valuable metals can be recovered efficiently from the fluidized medium. To increase the content of valuable metals in the fluid medium stored in the storage containers installed in the circulation path, it is necessary to circulate the fluid medium through the circulation path multiple times. Therefore, the recovery process in this method includes a measurement process for measuring the amount of valuable metals contained in the fluid medium. By measuring the amount of valuable metals contained in the fluid medium during the measurement process, it becomes possible to determine the content of valuable metals in the fluid medium. This allows the number of times the fluid medium is circulated through the circulation path in the circulation process to be adjusted in a way that increases the content of valuable metals in the fluid medium stored in the storage containers. .

[0008] Another feature is that the circulation process changes the circulation speed of the fluid medium based on the amount of the valuable metal measured in the measurement process.

[0009] According to this method, in the circulation process, the circulation rate of the fluid medium is changed according to the amount of valuable metal measured in the measurement process. For example, when the amount of valuable metal measured in the measurement process is small, the circulation rate of the fluid medium can be increased in order to increase the content of valuable metal in the fluid medium. As a result, the amount of valuable metal recovered from the fluid medium can be increased while continuing to operate the fluidized bed furnace.

[0010] The characteristic of the fluidized medium recovery method according to the present invention is that it is a fluidized medium recovery method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container, The recovery process involves removing the storage container and recovering the fluidized medium while the fluidized bed furnace is stopped.

[0011] According to this method, in the circulation process, the fluidized medium discharged from the outlet of the fluidized bed furnace is circulated through a circulation path, and a portion of the fluidized medium circulating through the circulation path is stored in a storage container provided in the circulation path. As a result, the fluidized medium discharged from the outlet is circulated through the circulation path and returned to the fluidized bed furnace, while valuable metals can be recovered from the fluidized medium stored in the storage container. In other words, valuable metals can be recovered by taking the fluidized medium from the storage container while continuing to operate the fluidized bed furnace. As a result, the operating efficiency of the fluidized bed furnace can be increased, and valuable metals can be recovered efficiently from the fluidized medium. . If long objects such as wires are mixed in with the storage container, it is difficult to extract only the fluidized medium from the storage container while continuing to operate the fluidized bed furnace. Therefore, in this method, during the recovery process, the storage container is removed and the fluidized medium is recovered while the fluidized bed furnace is stopped. This makes it easier to perform various treatments such as wind separation, vibration separation, and magnetic separation on the fluidized medium stored in the removed storage container to recover valuable metals after separating long objects such as wires. As a result, valuable metals can be easily recovered from the fluidized medium stored in the storage container. Note that the storage container may be removed as a whole, or only a part of the storage container, such as the bottom.

[0012] Another feature is that the circulation process maintains the storage container under negative pressure.

[0013] As in this method, in the circulation process, since the storage container is maintained at a negative pressure, the storage container has a lower pressure than the continuous circulation path from the furnace body, so the fluid medium in the circulation path easily flows into the storage container. As a result, the fluid medium circulating in the circulation path can return to the furnace body without flowing backward through the storage container.

[0014] The characteristic of the fluidized medium recovery method according to the present invention is that it is a fluidized medium recovery method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container, The aforementioned circulation process is characterized by maintaining the storage container under negative pressure. 。

[0015] According to this method, in the circulation process, the fluidized medium discharged from the outlet of the fluidized bed furnace is circulated through a circulation path, and a portion of the fluidized medium circulating through the circulation path is stored in a storage container provided in the circulation path. As a result, the fluidized medium discharged from the outlet is circulated through the circulation path and returned to the fluidized bed furnace, while valuable metals can be recovered from the fluidized medium stored in the storage container. In other words, valuable metals can be recovered by taking the fluidized medium from the storage container while continuing to operate the fluidized bed furnace. As a result, the operating efficiency of the fluidized bed furnace can be increased, and valuable metals can be recovered efficiently from the fluidized medium. As described in this method, maintaining a negative pressure in the storage container during the circulation process results in a lower pressure in the storage container than in the circulation path continuous with the furnace body, making it easier for the fluid medium in the circulation path to flow into the storage container. As a result, the fluid medium circulating in the circulation path can be returned to the furnace body without backflowing through the storage container.

[0016] The characteristic configuration of the fluidized bed furnace equipment according to the present invention includes a furnace body for accommodating a fluid medium and a discharge port capable of discharging the fluid medium from the furnace body, and is a fluidized bed furnace for incinerating or gasifying a treatment target containing valuable metals, and a circulation path for circulating the fluid medium discharged from the discharge port back to the furnace body. In the circulation path, a storage container for storing the fluid medium is provided to recover the valuable metals from the fluid medium. Occasionally, The storage container is provided at a bend in the circulation path and has an inlet and an outlet for the fluid medium, and is configured such that the direction in which the fluid medium flows in through the inlet and the direction in which the fluid medium flows out through the outlet intersect at an obtuse angle. 。

[0017] In this configuration, the fluidized bed furnace system circulates the fluidized medium discharged from the furnace outlet through a circulation path, and stores a portion of the circulating fluidized medium in a storage container located in the circulation path. This allows the fluidized medium discharged from the outlet to be circulated back into the fluidized bed furnace via the circulation path, while valuable metals can be recovered from the fluidized medium stored in the storage container. In other words, valuable metals can be recovered by taking the fluidized medium from the storage container while continuing to operate the fluidized bed furnace. As a result, the operating efficiency of the fluidized bed furnace can be increased, and valuable metals can be recovered efficiently from the fluidized medium. Storage containers installed in circulation paths are designed to be placed at bends in the path to facilitate the storage of a portion of the fluid circulating through the path. However, the fluid circulating through the path may contain non-combustible materials, such as long objects like wire. Therefore, in storage containers installed at bends, long objects that flow in with the fluid may accumulate and clog both the inlet and outlet sections, obstructing the flow of the fluid in the storage container. In this configuration, the storage container installed at a bend in the circulation path is designed so that the direction in which the fluid flows in through the inlet and the direction in which it flows out through the outlet intersect at an obtuse angle. This prevents long objects from getting stuck between the inlet and outlet sections of the storage container, even if they flow into it. As a result, clogging of the storage container with long objects can be easily prevented, allowing the fluid to circulate smoothly through the circulation path. . [Brief explanation of the drawing]

[0018] [Figure 1] This diagram schematically shows the configuration of the fluidized bed furnace equipment in the first embodiment. [Figure 2] This is a partial cross-sectional view showing the structure of the furnace bottom plate in a fluidized bed furnace. [Figure 3] This is a plan view showing the configuration of the diffuser pipes in a fluidized bed furnace. [Figure 4] This is a longitudinal cross-sectional view showing the configuration of the storage container in the first embodiment. [Figure 5] This is a cross-sectional view of a fluidized bed furnace with fluidized medium remaining on the furnace bottom plate. [Figure 6] This diagram schematically shows the configuration of the fluidized bed furnace equipment in the second embodiment. [Figure 7] This is a longitudinal cross-sectional view showing the configuration of the storage container in the second embodiment. [Figure 8] This is a longitudinal cross-sectional view showing the configuration of the storage container in Modification Example 1. [Figure 9] This is a side longitudinal cross-sectional view showing the configuration of the storage container in Modification Example 1. [Figure 10] This is a longitudinal cross-sectional view showing the configuration of the storage container in modified example 2. [Modes for carrying out the invention]

[0019] Hereinafter, a fluidized medium recovery method and fluidized bed furnace equipment according to embodiments of the present invention will be described in detail based on the drawings. The embodiments described below are illustrative examples for illustrating the present invention and do not limit the present invention to these embodiments only. Therefore, the present invention can be implemented in various forms without departing from its essence.

[0020] [First Embodiment] (Configuration of fluidized bed furnace equipment) The configuration of the fluidized bed furnace equipment 1 will be explained with reference to Figures 1 to 3. As shown in Figure 1, the fluidized bed furnace equipment 1 mainly consists of a fluidized bed gasifier 10 (an example of a fluidized bed furnace, hereinafter abbreviated as "fluidized bed furnace 10"), a swirling flow melting furnace 20, and a duct 30. These components will be explained below.

[0021] The fluidized bed furnace 10 is a facility for thermally decomposing various types of waste, such as municipal solid waste, sewage sludge, or automobile shredder residue (ASR), or various types of waste such as discarded home appliances, or combustible materials such as home appliances containing valuable metals, into combustible gas (carbon monoxide, hydrogen, hydrocarbons, etc.), unburned material (char), and ash. The waste to be processed includes valuable metals, and the fluidized bed furnace 10 incinerates or gasifies the waste to be processed. As shown in Figure 1, the fluidized bed furnace 10 is equipped with a furnace body 12 that houses a fluidized medium 13. The furnace body 12 (fluidized bed furnace 10) has a furnace bottom plate 16 that supports the fluidized medium 13, and an outlet 16a provided adjacent to the furnace bottom plate 16 that can discharge the fluidized medium 13. In this embodiment, a circular opening is formed in the central part of the furnace bottom plate 16, and the outlet 16a is formed by this opening. Furthermore, a discharge pipe 15 extending downward from the furnace bottom plate 16 is connected to the discharge port 16a. In addition, the fluidized bed furnace 10 is equipped with a diffuser mechanism A that blows fluidizing gas toward the fluidized medium 13. In this embodiment, the diffuser mechanism A is configured to blow the fluidizing gas from below the furnace bottom plate 16. Although not shown, the diffuser mechanism A may also be configured to blow the fluidizing gas from above the furnace bottom plate 16 and from the side of the furnace body 12.

[0022] The furnace body 12 has a cylindrical shape, for example, extending vertically. The furnace body 12 is provided with a supply port 14, an outlet port 11, and an inlet port 17. The material to be processed is supplied into the furnace body 12 from the supply port 14. The combustible gas generated inside the furnace body 12 is discharged outside the furnace from the outlet port 11. As a diffusion mechanism A, a wind box 18 is provided in the space below the furnace bottom plate 16 inside the furnace body 12, and a fluidizing gas (for example, air) for fluidizing the fluidizing medium 13 is introduced into the wind box 18 from the inlet port 17. As shown in Figure 1, the supply port 14 is provided on the side of the furnace body 12 in a part above the furnace bottom plate 16. The outlet port 11 is provided at the top of the furnace body 12. The inlet port 17 is provided on the side of the furnace body 12 in a part below the furnace bottom plate 16.

[0023] The furnace bottom plate 16 is located at the bottom of the furnace body 12. The discharge port 16a for the fluidizing medium 13 is formed on the inner circumference of the furnace bottom plate 16. Numerous diffuser pipes 19 penetrate the furnace bottom plate 16. As shown in Figure 1, the furnace bottom plate 16 is inclined downward toward the inner circumferential outlet 16a, and its inclination angle is smaller than the angle of repose of the fluid medium 13. Specifically, while the angle of repose of the fluid medium 13 is preferably 30 to 40 degrees, the inclination angle of the furnace bottom plate 16 is 10 to 30 degrees. In Figure 5, the inclination angle (angle θ) of the furnace bottom plate 16 is shown as the angle between the horizontal direction (dotted line Y in Figure 5) and the surface 16c of the furnace bottom plate 16. In this embodiment, the entire furnace bottom plate 16 is inclined at an angle smaller than the angle of repose of the fluid medium 13, but the furnace bottom plate 16 may also be configured such that only a part of it is inclined at an angle smaller than the angle of repose of the fluid medium 13.

[0024] The fluidized medium 13 is, for example, fluidized sand such as silica sand or olivine sand, and is filled on the furnace bottom plate 16. As a result, a fluidized bed (sand layer) of a predetermined thickness is formed on the furnace bottom plate 16, as shown in Figure 1. The fluidized bed furnace 10 processes materials containing valuable metals (for example, gold, silver, copper, lead, or zinc) while the fluidized medium 13 is in a fluid state.

[0025] The discharge pipe 15 is for draining the fluid medium 13 along with non-combustible material to the outside of the furnace body 12. As shown in Figure 1, the discharge pipe 15 has an upper end connected to the discharge port 16a and a lower end located outside the furnace body 12, and extends vertically from the upper end to the lower end, penetrating the bottom wall of the furnace body 12.

[0026] Aeration mechanism A consists of an inlet 17, a wind box 18, and a plurality of diffusers 19. As shown in Figures 2 and 3, each diffuser 19 has a straight pipe section 19a that penetrates the furnace bottom plate 16 in the thickness direction, and a U-shaped pipe section 19b connected to the upper end of the straight pipe section 19a. As shown in Figure 1, in order to make the fluidizing medium 13 fluid, aeration mechanism A circulates the fluidizing gas introduced from the inlet 17 to the wind box 18 through the diffusers 19, blowing the fluidizing gas from below the furnace bottom plate 16 of the furnace body 12 toward the fluidizing medium 13. As shown in Figure 3, a plurality of diffusers 19 are arranged radially on the furnace bottom plate 16. The fluidizing gas introduced from the inlet 17 to the wind box 18 rises inside the straight pipe section 19a and is then sent toward the fluidizing medium 13 from the opening of the U-shaped pipe section 19b (arrow in Figure 3).

[0027] As shown in Figure 1, the swirling flow melting furnace 20 is a furnace that completely combusts the combustible gas and unburned material while forming a swirling flow 100 of the combustible gas generated in the fluidized bed furnace 10, and also melts the ash entrained in the combustible gas. The swirling flow melting furnace 20 has a melting furnace body 23. The melting furnace body 23 is provided with a combustible gas inlet 21 and a slag outlet 22 for discharging molten slag to the outside of the furnace. Molten slag is formed when the ash of the combustible gas that flows into the melting furnace body 23 from the inlet 21 melts.

[0028] The inlet 21 is located on the side of the melting furnace body 23, near the top. The inlet 21 is connected to the outlet 11 of the fluidized bed gasifier 10 by a duct 30. The slag outlet 22 is located at the bottom of the melting furnace body 23. The exhaust gas generated by the combustion of combustible gas in the swirling flow melting furnace 20 passes through various equipment (boiler, cooling tower, bag filter, catalytic reaction tower, etc.) located downstream of the swirling flow melting furnace 20, and is then released into the atmosphere through a chimney (not shown).

[0029] The fluidized bed furnace 10 has a circulation path 40. The circulation path 40 returns the fluidized medium 13, which has been extracted to the outside of the furnace body 12, to the furnace body 12 after being separated from non-combustible materials. The circulation path 40 includes an extraction screw 41, a classifier 42, a circulation elevator 43, a storage container 50, a storage tank 45, a first transport path 46, a second transport path 47, and a third transport path 48.

[0030] The extraction screw 41 is used to extract the fluid medium 13 together with non-combustible material from the bottom of the furnace body 12 by rotational drive, and is located at the lower end of the discharge pipe 15. The classifier 42 is located at the downstream end of the extraction screw 41 and separates the fluid medium 13 from the non-combustible material by sieving. The non-combustible material separated from the fluid medium 13 is crushed and then slag-formed in the swirling flow melting furnace 20, or transported out of the system.

[0031] The circulating elevator 43 transports the fluid medium 13, from which non-combustible materials have been removed by the classification device 42, to a predetermined height. As shown in Figure 1, an inlet 43A for the fluid medium 13 is provided at the bottom of the circulating elevator 43, and this inlet 43A is connected to the outlet 42A of the classification device 42 (the outlet for the fluid medium 13) by the first transport path 46. An outlet 43B for the fluid medium 13 is also provided at the top of the circulating elevator 43.

[0032] The second transport path 47 is provided from the outlet 43B of the circulating elevator 43 toward the supply port 14 of the furnace body 12, with a magnetic separator 44 and a storage container 50 positioned along the way. The magnetic separator 44 is connected to the non-combustible material recovery path 49. The third transport path 48 branches off from the second transport path 47 and is connected to the inlet of the storage tank 45. This allows the fluid medium 13 that exits the outlet 43B of the circulating elevator 43 to be returned to the furnace body 12 via the second transport path 47 and temporarily stored in the storage tank 45 via the third transport path 48. Although not shown in the diagram, the circulation path 40 may further include a switching unit (valve, etc.) to switch whether the fluid medium 13 that exits the outlet 43B of the circulating elevator 43 is guided to the storage tank 45 or to the furnace body 12.

[0033] As shown in Figures 1 and 4, the storage container 50 stores the fluidized medium 13 in order to recover valuable metals from the fluidized medium 13. The storage container 50 is located downstream of the circulation path 40 and upstream of the fluidized bed furnace 10. Specifically, the storage container 50 is located downstream of the outlet 43B of the circulation elevator 43, which is the outlet for the fluidized medium 13 from which non-combustible materials have been removed by magnetic separation by the magnetic separator 44. As shown in Figure 4, the storage container 50 has an upper part 51, a side part 52, and a lower part 53. An inlet 54 is provided in the upper part 51, an outlet 55 that slopes downward is provided in the side part 52, and a discharge part 56 is provided in the lower part 53. As a result, in the storage container 50, the fluidized medium 13 accumulates with its upper surface sloped along the angle of repose θ2, while the outlet 55 flows out. The inlet 54 and the outlet 55 are connected to the second transport path 47. The discharge section 56 is provided with an on-off valve V, and the fluid medium 13 can be removed by opening the on-off valve V.

[0034] As shown in Figure 1, the fluidized bed furnace equipment 1 includes a dust collector 57 and a fan 58 that operates the dust collector 57, and is connected to the circulation path 40. The dust collector 57 is connected to the top of the circulation elevator 43 and sucks up dust contained in the fluidized medium 13 flowing through the circulation path 40. The dust collector 57 also sucks up dust contained in the fluidized medium 13 flowing through the storage container 50 via a suction channel 59 connected to the top of the storage container 50. At this time, the top of the circulation elevator 43 and the inside of the storage container 50, which is located downstream of the circulation elevator 43, are made negatively pressurized. The dust collector 57 is also connected to the second transport path 47, downstream of the magnetic separator 44 and upstream of the storage container 50. As a result, the fluidized medium 13 collected by the dust collector 57 is returned to the circulation path 40.

[0035] A measuring instrument 61 is connected to the storage container 50 to measure the amount of valuable metals contained in the fluidized medium 13 by extracting a portion of the fluidized medium 13 stored in the storage container 50 from the discharge section 56. The fluidized bed furnace equipment 1 is equipped with a control unit 60 that controls operation. This control unit 60 consists of a processor such as a CPU and memory, and functions through the cooperation of software and hardware. The control unit 60 is configured to change the circulation speed of the fluidized medium 13 based on the amount of valuable metals obtained by the measuring instrument 61. In this embodiment, the control unit 60 is configured to change the drive speed of each component, such as the extraction screw 41 and the circulation elevator 43.

[0036] The storage container 50 is located at a bend C in the second transport path 47 of the circulation path 40. By placing the storage container 50 at a bend C in the circulation path 40, it becomes easier to store a portion of the fluid medium 13 circulating in the circulation path 40. However, the fluid medium 13 circulating in the circulation path 40 contains non-combustible materials, which may include long objects L (see Figure 4), such as wire. Therefore, in the storage container 50 located at a bend C, long objects L that flow in with the fluid medium 13 may get caught between the inlet 54 and outlet 55, and in that case, the long objects L will obstruct the flow of the fluid medium 13 in the storage container 50.

[0037] Therefore, the storage container 50 in this embodiment is configured such that the direction in which the fluid medium 13 flows in through the inlet 54 and the direction in which the fluid medium 13 flows out through the outlet 55 intersect at an obtuse angle, thus preventing clogging by long objects L contained in the noncombustible material. Specifically, in the storage container 50, the inlet 54 extends vertically from the upper part 51, and the outlet 55 extends downward from the side part 52, with the inflow direction D1 from the inlet 54 and the outflow direction D2 from the outlet 55 intersecting at an obtuse angle θ3. The angle θ3 should be 100 degrees or more, preferably 120 degrees or more, and even more preferably 150 degrees or more. As a result, as shown in Figure 4, even if long objects L flow into the storage container 50 provided at the bend C of the circulation path 40, the long objects L are less likely to accumulate across the inlet 54 and outlet 55 of the storage container 50 and are less likely to clogging. As a result, clogging of the storage container 50 by long objects L can be easily prevented, and the fluid medium 13 can be smoothly circulated in the circulation path 40.

[0038] The storage tank 45 is located downstream of the magnetic separator 44 in the second transport path 47 and stores the fluid medium 13 that has been transported upward by the circulating elevator 43. As a result, the fluid medium 13 that has been transported upward by the circulating elevator 43 can be dropped into the storage tank 45 via the third transport path 48 after the magnetic separator 44 has removed any long, magnetic objects such as wires, and then stored in the storage tank 45.

[0039] <Method for recovering fluidized medium in a fluidized bed furnace> (First recovery method) The first method for recovering the fluidized medium 13 in the fluidized bed furnace 10 will be described. This recovery method involves continuing the operation of the fluidized bed furnace 10 and recovering the fluidized medium 13 from inside the furnace body 12.

[0040] As shown in Figure 1, before maintenance of the fluidized bed furnace 10, i.e., during steady-state operation of the fluidized bed furnace 10, the fluidized medium 13 is in a fluidized state due to the fluidizing gas (e.g., air) supplied through the diffuser pipe 19, and the material to be processed is supplied into the furnace body 12 from the supply port 14. The material to be processed is heated by the fluidized medium 13 in the furnace body 12 and thermally decomposed into combustible gas, unburned material, and ash. Here, the material to be processed contains a considerable amount of valuable metals such as precious metals (gold, silver, copper, etc.) and heavy metals (lead, zinc, etc.).

[0041] The combustible gas generated in the fluidized bed furnace 10 flows into the swirling flow melting furnace 20 through the duct 30 along with unburned material and ash. In the swirling flow melting furnace 20, the combustible gas and unburned material are completely combusted and the ash melts. During this steady-state operation, the circulation path 40 is activated to remove the fluidized medium 13 filled in the furnace body 12 along with the non-combustible material from the furnace, and to return the fluidized medium 13 from which the non-combustible material has been removed back into the furnace body 12.

[0042] The fluid medium 13 filled inside the furnace body 12 is drawn out of the furnace body 12 by gravity through the discharge port 16a. Specifically, by rotating the extraction screw 41, the fluid medium 13 filled inside the furnace body 12 is drawn out of the furnace body 12 through the discharge pipe 15 which is connected to the discharge port 16a.

[0043] The fluidized medium 13 extracted from the furnace is separated from non-combustible materials by a classifier 42, transported upward by a circulation elevator 43, and then returned to the furnace body 12, with a portion of it being stored in a storage container 50. In other words, in the first recovery method, a circulation process is first performed in which the fluidized medium 13 extracted from the discharge port 16a is circulated through the circulation path 40. When the fluidized bed furnace 10 is stopped, the fluidized medium 13 extracted from the furnace is stored in a storage tank 45.

[0044] Furthermore, in the circulation process, a dust collector 57 and a fan 58 connected to the top of the circulation elevator 43 of the circulation path 40 maintain the storage container 50 at a negative pressure relative to the internal pressure of the furnace body 12 of the fluidized bed furnace 10. As a result, the storage container 50 is at a lower pressure than the circulation path 40 which is continuous with the furnace body 12, making it easier for the fluidized medium 13 circulating in the circulation path 40 to flow into the storage container 50.

[0045] Next, in the recovery process, the fluid medium 13 is recovered from the storage container 50. Then, valuable metals are recovered from the fluid medium 13 recovered in the recovery process by a predetermined method. The predetermined method involves separating the valuable metals contained in the fluid medium 13 from the fluid medium 13 by methods such as heat treatment, chemical treatment, or physical separation. Examples of heat treatment include melting (smelting), calcination, or chlorination. Examples of chemical treatment include solvent extraction such as acid. Examples of physical separation include wind separation, magnetic separation, vibration separation, eddy current separation, electrostatic separation, or specific gravity separation.

[0046] The recovery process includes a measurement process for measuring the amount of valuable metals contained in the fluid medium 13 stored in the storage container 50. Specifically, the measurement process is performed by a measuring instrument 61 connected to the storage container 50. In the fluidized bed furnace equipment 1, a portion of the fluid medium 13 in the storage container 50 is extracted and supplied to the measuring instrument 61. The measurement process may be performed in parallel with the circulation process, or when the circulation process is periodically stopped. In the measurement process, the amount of valuable metals contained in the fluid medium 13 is measured by the measuring instrument 61, thereby determining the content of valuable metals in the fluid medium 13. This allows the number of times the fluid medium 13 is circulated through the circulation path 40 in the circulation process to be adjusted so as to increase the content of valuable metals in the fluid medium 13 stored in the storage container 50.

[0047] In the circulation process, the circulation speed of the fluid medium 13 may be changed based on the amount of valuable metal measured in the measurement process. Specifically, the control unit 60 changes the drive speed of the extraction screw 41, the circulation elevator 43, etc., based on the amount of valuable metal measured by the measuring instrument 61, thereby changing the circulation speed of the fluid medium 13 in the circulation path 40. This allows, for example, when the amount of valuable metal measured in the measurement process is small, the circulation speed of the fluid medium 13 to be increased in order to increase the valuable metal content in the fluid medium 13.

[0048] (Second recovery method) A second method for recovering the fluidized medium 13 in the fluidized bed furnace 10 will be described. This recovery method is used to recover the fluidized medium 13 from inside the furnace body 12 when the fluidized bed furnace 10 is stopped, for example, during maintenance of the fluidized bed furnace 10.

[0049] When it is time for maintenance of the fluidized bed furnace 10, first, the supply of the material to be processed to the furnace body 12 is stopped. Next, the supply of fluidizing gas to the wind box 18 is stopped. In other words, the aeration mechanism A is stopped. After that, an extraction process is performed in which the fluidized medium 13 filled in the furnace body 12 is extracted to the outside of the furnace body 12.

[0050] In the extraction process, the fluid medium 13 filled inside the furnace body 12 is extracted to the outside of the furnace body 12 by gravity through the discharge port 16a. Specifically, by rotating the extraction screw 41, the fluid medium 13 filled inside the furnace body 12 is extracted to the outside of the furnace body 12 through the discharge pipe 15 which is connected to the discharge port 16a.

[0051] The fluid medium 13 extracted from the furnace is separated from non-combustible materials by a classifier 42, transported upward by a circulating elevator 43, and then stored in a storage tank 45. In other words, during the extraction process, the fluid medium 13 extracted from the furnace body 12 is not returned to the furnace body 12, but is all stored in the storage tank 45.

[0052] Figure 5 schematically shows the state inside the furnace body 12 (the vicinity of the furnace bottom plate 16) after the extraction process described above. As mentioned above, the furnace bottom plate 16 is inclined downward toward the outlet 16a at an angle θ smaller than the angle of repose of the fluidizing medium 13. For this reason, as shown in Figure 5, not all of the fluidizing medium 13 inside the furnace body 12 is extracted out of the furnace during the extraction process, and some of the fluidizing medium 13 remains on the furnace bottom plate 16 as a deposit layer 13a after the extraction process. More specifically, there is a region (immobile layer) that is less affected by the fluidizing gas between the upper surface of the furnace bottom plate 16 and the U-shaped pipe section 19b of the diffuser pipe 19, and a certain amount of fluidizing medium 13 remains in this immobile layer.

[0053] Of the fluidized medium 13 filled into the furnace body 12 before the extraction process, the majority (for example, 99%) is sent to the storage tank 45 during the extraction process, and the remainder remains on the furnace bottom plate 16 as a deposit layer 13a. Here, it is known that in the fluidized bed furnace 10, the furnace bottom medium after the extraction process contains high concentrations of valuable metals (gold, silver, copper, lead, zinc, etc.) derived from the material being processed.

[0054] Therefore, in the second recovery method, in the recovery process following the extraction process, the fluid medium 13 in the deposited layer 13a is recovered separately from the fluid medium 13 extracted from inside the furnace body 12 in the extraction process (the fluid medium 13 stored in the storage tank 45). Specifically, after the extraction process is completed, an operator enters the furnace body 12 and collects the deposited layer 13a, thereby directly recovering the fluid medium 13 in the deposited layer 13a from inside the furnace body 12.

[0055] Subsequently, the worker performs maintenance work such as cleaning and inspecting the inside of the furnace body 12. Note that cleaning and inspection of the furnace may be performed before recovering the remaining fluid medium 13, or the recovery of the fluid medium 13 remaining on the furnace bottom plate 16 and the maintenance work inside the furnace body 12 may be performed concurrently. In other words, the recovery process should be carried out after stopping the aeration mechanism A.

[0056] Thus, in the second recovery method, the fluidized bed gasifier 10 is maintained, and the fluidized medium 13 containing a high concentration of valuable metals derived from the material being processed is recovered. In this embodiment, the circulation rate of the fluidized medium 13 is changed based on the amount of valuable metals measured in the measurement process, so the fluidized medium 13 in the deposited layer 13a contains a high concentration of valuable metals.

[0057] Finally, the valuable metals are separated from the fluid medium 13 recovered in the recovery process. Specifically, the valuable metals contained in the furnace bottom medium are separated from the fluid medium 13 by methods such as heat treatment, chemical treatment, or physical separation. Examples of heat treatments include melting (smelting), calcination, or chlorination. Examples of chemical treatments include solvent extraction with acids, etc. Examples of physical separations include wind separation, magnetic separation, vibration separation, eddy current separation, electrostatic separation, or specific gravity separation.

[0058] In this embodiment, by recovering the fluidized medium 13 contained in the fluidized bed furnace 10 using the first recovery method described above, valuable metals can be efficiently recovered from the fluidized medium 13 while the fluidized bed furnace 10 continues to operate. Furthermore, by recovering the fluidized medium 13 contained in the fluidized bed furnace 10 using the second recovery method described above, valuable metals can be efficiently recovered from the fluidized medium 13 remaining on the furnace bottom plate 16 when the fluidized bed furnace 10 is stopped.

[0059] [Second Embodiment] The fluidized bed furnace equipment 1 of the second embodiment will be described with reference to Figures 6 and 7. Hereinafter, only the differences from the first embodiment will be described. The second embodiment differs from the first embodiment in that the storage container 50 is provided in the first transport path 46. Also, unlike the first embodiment, the fluidized bed furnace equipment 1 of the second embodiment shown in Figure 6 is not equipped with a dust collector 57 and a fan 58. The method for recovering the fluidized medium 13 in the fluidized bed furnace 10 according to the second embodiment is basically the same as the method for recovering the fluidized medium 13 in the fluidized bed furnace 10 according to the first embodiment.

[0060] In the second embodiment, the storage container 50 is provided at a bend C in the first transport path 46 of the circulation path 40. The storage container 50 has an upper part 51, a side part 52, and a lower part 53. An inlet 54 is provided in the upper part 51, and an outlet 55 is provided in the side part 52. The inlet 54 and the outlet 55 are connected to the first transport path 46.

[0061] In this embodiment as well, the storage container 50 is configured such that the direction in which the fluid medium 13 flows in through the inlet 54 and the direction in which the fluid medium 13 flows out through the outlet 55 intersect at an obtuse angle, thereby preventing clogging by long pieces L contained in the noncombustible material. Specifically, in the storage container 50, the inlet 54 extends vertically from the upper part 51, and the outlet 55 extends downward from the side part 52, with the inflow direction D1 through the inlet 54 and the outflow direction D2 through the outlet 55 intersecting at an obtuse angle θ3.

[0062] Furthermore, a measuring instrument 61 is connected to the storage container 50 to measure the amount of valuable metals contained in the fluid medium 13 by taking out a portion of the fluid medium 13 stored in the storage container 50. The control unit 60 is configured to change the circulation speed of the fluid medium 13 based on the amount of valuable metals obtained by the measuring instrument 61. Specifically, the fluidized bed furnace 10 is configured so that the drive speed of the extraction screw 41, the circulation elevator 43, etc. can be changed by the control unit 60. In the example shown in Figure 7, a discharge section and an on-off valve are not provided at the bottom 53 of the storage container 50, but as in the first embodiment, a discharge section 56 and an on-off valve V may be provided at the bottom of the storage container 50.

[0063] [Modification example of a storage container 1] As shown in Figures 8 and 9, the storage container 50 may have multiple tubular diffusers 71 arranged in parallel inside, extending horizontally. Fluidized gas is supplied from the outside to the diffusers 71 and flows out towards the fluidized medium 13 through outlet holes formed at the bottom of the diffusers 71. As a result, the fluidized medium 13 flows inside the storage container 50, and the valuable metals contained in the fluidized medium 13 are concentrated.

[0064] In the storage container 50 of this modified example 1, the outlet section 55 extends diagonally downward from the side section 52 of the storage container 50, and is configured to allow the fluid medium 13 that overflows from the storage container 50 to flow out. The lower part 53 of the storage container 50 is inclined downward toward the central part, and a discharge section 56 is provided in the central part. The discharge section 56 is configured to have a slide gate at its lower part. The slide gate has at least a bottom surface 56a that is inclined downward and side surfaces 56b provided on both sides of the bottom surface 56a. In the example shown in Figure 8, the upper part of the slide gate is open in the discharge section 56. Although not shown, the slide gate in the discharge section 56 may be formed in a tubular shape. By having a slide gate, the discharge section 56 can smoothly discharge the fluid medium 13 from the storage container 50 to the outside.

[0065] As shown in Figure 9, adjacent diffusers 71A and 71B are arranged at a pitch P. The pitch P is set wide to prevent long objects such as wires from accumulating across the two diffusers 71A and 71B. In the example shown in Figure 9, two diffusers 71 are arranged in the storage container 50, but three or more diffusers 71 may be arranged in the storage container 50.

[0066] [Modification of storage container 2] As shown in Figure 10, the storage container 50 may have a lower section 53 that slopes downward toward the discharge section 56 and multiple diffusers 72 that protrude toward the fluid medium 13 from the lower section 53. The diffusers 72 shown in Figure 10 have the same configuration as the diffusers 19 provided on the furnace bottom plate 16 of the furnace body 12 (see Figure 2). The inclination angle (angle θ4) of the lower section 53 is shown as the angle between the horizontal direction (dotted line Y in Figure 10) and the surface 53a of the lower section 53. The angle θ4 is set to be smaller than the angle of repose of the fluid medium 13, just like the angle θ (see Figure 5), which is the inclination angle of the furnace bottom plate 16 of the furnace body 12. As a result, inside the storage container 50, the valuable metals contained in the fluid medium 13 are concentrated in the fluid medium 13 that accumulates near the diffusers 72, forming a static layer 13b. As a result, when the fluid medium 13 is discharged from the discharge section 56, it becomes easier to leave the fluid medium 13 in the immobile layer 13b in the storage container 50, and thus valuable metals can be efficiently recovered from the fluid medium 13 remaining in the storage container 50.

[0067] Although not shown in the diagram, the inclination angle (angle θ4) of the lower part 53 may be set to an angle greater than the angle of repose of the fluid medium 13. In this case, the fluid medium 13 in the storage container 50 may be completely recovered via the discharge section 56.

[0068] [Another embodiment] (1) In the above embodiment, the storage container 50 is fixed to the circulation path 40. In this case, if long objects such as wires are mixed in with the storage container 50, it is difficult to remove only the fluid medium 13 from the storage container 50 while continuing to operate the fluid bed furnace 10. Therefore, the storage container 50 provided in the circulation path 40 may be configured to be removable from the circulation path 40. In this case, the recovery process can be carried out by removing the storage container 50 while the fluid bed furnace 10 is stopped, separating the long objects such as wires from the fluid medium 13, and then recovering it. In this way, it becomes easier to perform various treatments such as wind separation, vibration separation, and magnetic separation to separate valuable metals from the fluid medium 13 stored in the storage container 50 that has been removed from the circulation path 40. As a result, valuable metals can be easily recovered from the fluid medium 13 stored in the storage container 50. Furthermore, the storage container 50 may be removed as a whole, or it may be removed as a part of the storage container 50, such as the lower part 53 (bottom).

[0069] (2) In the above embodiment, an example was shown in which a measuring instrument 61 for measuring the amount of valuable metal contained in the fluid medium 13 is connected to the storage container 50. Alternatively, a measuring instrument for measuring the amount of valuable metal contained in the fluid medium 13 by taking out a portion of the fluid medium 13 may be connected to any of the first transport path 46 to the third transport path 48, where the storage container 50 is not located, and the circulation speed of the fluid medium 13 may be changed based on the amount of valuable metal measured by the measuring instrument.

[0070] (3) The storage container 50 may have only an inlet 54 and an outlet 55 connected to the first transport path 46 or the second transport path 47. In this case, it is preferable to provide an inspection port so that the amount of fluid medium 13 stored in the storage container 50 can be checked in order to periodically remove the fluid medium 13 from the storage container 50.

[0071] (4) In the above embodiment, the inclination angle of the furnace bottom plate 16 was set to an angle θ smaller than the angle of repose of the fluid medium 13, and an example was shown in which the fluid medium 13 remained on the furnace bottom plate 16 when the fluid medium 13 was extracted from the discharge port 16a. However, the inclination angle of the furnace bottom plate 16 may be set to an angle larger than the angle of repose of the fluid medium 13. In this case, only the first recovery method may be implemented for the fluid medium recovery method in the fluidized bed furnace 10.

[0072] (5) In the second embodiment described above, an example was shown in which the fluidized bed furnace equipment 1 does not include a magnetic separator 44, a dust collector 57, and a fan 58. However, in the second embodiment as well, the fluidized bed furnace equipment 1 may be configured to include a magnetic separator 44, a dust collector 57, and a fan 58, just as in the first embodiment.

[0073] (6) In the above embodiment, an example was shown in which a fluidized bed gasifier 10 that gasifies the material to be processed is used as the fluidized bed furnace 10, but a fluidized bed incinerator that incinerates the material to be processed can also be used as the fluidized bed furnace 10.

[0074] (7) In the above embodiment, an example was shown in which the furnace body 12 of the fluidized bed furnace 10 is formed in a cylindrical shape, but the furnace body 12 of the fluidized bed furnace 10 may also be in a rectangular tubular shape.

[0075] (8) In the above embodiment, an example was shown in which the discharge port 16a is located on the central side in a plan view of the furnace body 12, that is, on the inner circumference side of the furnace bottom plate 16. However, the discharge port 16a may be located between the inner surface 12a of the furnace body 12, which is on the outer circumference side of the furnace bottom plate 16 in a plan view of the furnace body 12, and the furnace bottom plate 16.

[0076] (9) In the above embodiment, an example was shown in which the diffuser pipe 19 protrudes upward from the furnace bottom plate 16. However, the fluidized bed furnace 10 may also be configured such that the diffuser pipe 19 does not protrude upward from the furnace bottom plate 16. In other words, the diffuser pipe 19 ejects the fluidizing gas from the surface 16c of the furnace bottom plate 16. [Industrial applicability]

[0077] The present invention is widely applicable to fluidized bed furnaces that incinerate or gasify materials containing valuable metals, and to methods for recovering fluidized media in fluidized bed furnaces. [Explanation of Symbols]

[0078] 1:Fluidized bed furnace equipment 10: Fluidized bed gasifier (fluidized bed furnace) 11: Outlet 12: Furnace body 13: Fluid medium 15: Discharge pipe 16: Furnace bottom plate 16a: Outlet 19: Diffuser pipe 20: Swirling flow melting furnace 40: Circulation path 43: Circulating elevator 44:Magnetic separator 45: Storage tank 46: First transport route 47: Second transport route 48: Third transport route 49: Recovery Route 50: Storage container 51: Top 52: Side 53: Lower part 54:Inflow part 55: Outlet 56: Discharge section 57: Dust collector 58: Fan 60: Control Unit 61: Measuring Instruments A: Aeration mechanism C: Bend area D1:Inflow direction D2:Outflow direction L: Long items θ: angle θ2 :Angle θ3: Angle

Claims

1. A method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container, A fluid medium recovery method comprising a measurement step for measuring the amount of the valuable metal contained in the fluid medium.

2. The fluid medium recovery method according to claim 1, wherein the circulation step changes the circulation speed of the fluid medium based on the amount of the valuable metal measured in the measurement step.

3. A method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container, The recovery step is a fluidized medium recovery method in which the storage container is removed and the fluidized medium is recovered while the fluidized bed furnace is stopped.

4. The fluid medium recovery method according to any one of claims 1 to 3, wherein the circulation step maintains the storage container under negative pressure.

5. A method for recovering a fluidized medium from a fluidized bed furnace facility, The aforementioned fluidized bed furnace equipment is A fluidized bed furnace having a furnace body for containing the fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, for incinerating or gasifying a material to be processed that contains valuable metals, A circulation path for circulating the fluid medium discharged from the outlet back to the furnace body, The circulation path is provided with a storage container for storing the fluid medium, and comprises A circulation step of circulating the fluid medium through the circulation path, The process includes a recovery step of recovering the fluid medium from the storage container, The circulation process is a method for recovering a fluid medium while maintaining a negative pressure in the storage container.

6. A fluidized bed furnace having a furnace body for containing a fluidized medium and a discharge port from which the fluidized medium can be discharged from the furnace body, which incinerates or gasifies a material to be processed that contains valuable metals, The system includes a circulation path for circulating the fluid medium discharged from the outlet back into the furnace body, The circulation path is provided with a storage container for storing the fluid medium in order to recover the valuable metal from the fluid medium. The fluidized bed furnace equipment is configured such that the storage container is provided at a bend in the circulation path, has an inlet and an outlet for the fluidized medium, and the direction in which the fluidized medium flows in through the inlet and the direction in which the fluidized medium flows out through the outlet intersect at an obtuse angle.

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