Carbon dioxide recovery device

Abstract

To provide a carbon dioxide absorption device where the absorption efficiency of carbon dioxide can be enhanced.SOLUTION: A carbon dioxide recovery device 10 comprises: a carbon dioxide absorption tower 11 constituted so that carbon dioxide contained in a gas supplied from a gas source is absorbed in a carbon dioxide absorption solution; each stage gas-liquid contact part 53, 56 constituted so as to be positioned in a carbon dioxide absorption chamber installed at the inside of the carbon dioxide absorption tower 11 and rotated around an axis line approximately parallel to a vertical direction by the driving force of a driving force source 40; and an inner shaft part 512 constituted so as to supply the carbon dioxide absorption solution to the rotation center of the top surface of each stage gas-liquid contact part 53, 56. In the top surface of each stage gas-liquid contact part 53, 56, height becomes low as it goes apart from the rotation center.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001] The present invention relates to a carbon dioxide recovery device.

Background Art

[0002] Conventionally, as described in Patent Document 1 and Patent Document 2, there is provided a rotating cylindrical gas-liquid contact part (described as a hollow cylinder in Patent Document 1 and as a rotating cylinder in Patent Document 2), and a carbon dioxide absorption solution is permeated and passed from the inner peripheral side to the outer peripheral side of the gas-liquid contact part, and a gas containing carbon dioxide is passed from the outer peripheral side to the inner peripheral side of the gas-liquid contact part. A carbon dioxide recovery device configured as such is known.

[0003] According to these carbon dioxide recovery devices, the gas and the carbon dioxide absorption solution are brought into gas-liquid contact inside the gas-liquid contact part, so that the carbon dioxide contained in the gas is absorbed by the carbon dioxide absorption solution. In such carbon dioxide recovery devices, in order to increase the carbon dioxide absorption efficiency (the ratio indicating the amount of carbon dioxide absorbed by the carbon dioxide absorption solution with respect to the amount of carbon dioxide contained in the gas), it is required to permeate the carbon dioxide absorption liquid over a wide range (preferably throughout) inside the cylindrical gas-liquid contact part.

[0004] Patent Document 1 discloses a configuration in which a nozzle head is disposed in the internal space of a cylindrical gas-liquid contact part, and a carbon dioxide absorption solution is injected from the nozzle head toward the inner peripheral surface of the gas-liquid contact part. Patent Document 2 discloses a configuration in which a liquid distributor injects a carbon dioxide absorption solution over substantially the entire inner peripheral surface of the gas-liquid contact part (that is, over substantially the entire axial length of the gas-liquid contact part). However, Patent Document 1 does not disclose a configuration for permeating the carbon dioxide absorption solution over a wide range of the gas-liquid contact part. Further, in the configurations disclosed in Patent Document 1 and Patent Document 2, a structure (nozzle head and liquid distributor) for injecting the carbon dioxide absorption solution toward the inner peripheral surface of the gas-liquid separation part is required, and it is necessary to pump the carbon dioxide absorption solution for injection of the carbon dioxide absorption solution. Therefore, it causes an increase in device cost and an increase in energy consumption.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] (Problems to be Solved by the Invention) In view of the above circumstances, one of the objects of the present invention is to provide a carbon dioxide recovery device that can increase the absorption efficiency of carbon dioxide without causing an increase in equipment cost and an increase in energy consumption.

[0007] (Means for Solving the Problems) The carbon dioxide recovery device according to the present invention includes a carbon dioxide absorption tower configured to absorb carbon dioxide contained in the gas fed from a gas source into a carbon dioxide absorption solution, a gas-liquid contact part disposed in a carbon dioxide absorption chamber provided inside the carbon dioxide absorption tower, through which the carbon dioxide absorption solution can penetrate and the gas can pass, and configured to rotate about an axis substantially parallel to the vertical direction by the driving force of a driving force source, a carbon dioxide absorption solution supply part configured to supply the carbon dioxide absorption solution to the rotation center part on the upper surface of the gas-liquid contact part, and the upper surface of the gas-liquid contact part has a portion where the height decreases as it moves away from the rotation center part.

[0008] The carbon dioxide absorption solution supplied to the rotation center part on the upper surface of the gas-liquid contact part penetrates and diffuses toward the outer peripheral side and the lower side of the gas-liquid contact part due to the centrifugal force and gravity caused by the rotation of the gas-liquid contact part. For this reason, when the gas-liquid contact part has a simple cylindrical shape, it is difficult for the carbon dioxide absorption solution to diffuse and penetrate into the upper part and the outer peripheral part of the gas-liquid contact part. That is, in the upper part and the outer peripheral part of the gas-liquid contact part, a region where the amount of the carbon dioxide absorption solution that has penetrated is small is formed. And since the gas passing through this region has little chance of contacting the carbon dioxide absorption solution, the amount of carbon dioxide absorbed becomes small. Therefore, with such a configuration, the absorption efficiency of carbon dioxide decreases.

[0009] According to the carbon dioxide recovery device according to the present invention, since the height of the upper surface of the gas-liquid contact part decreases as it moves away from the rotation center part, it is possible to prevent the formation of a region where the carbon dioxide absorption solution does not spread (or reduce such a region) in the upper part and the outer peripheral part of the gas-liquid contact part. And according to such a configuration, the configuration of the carbon dioxide recovery device does not become complicated, and the energy consumption does not increase in order to spread carbon dioxide over a wide range of the gas-liquid contact part. Therefore, it is possible to increase the absorption efficiency of carbon dioxide while preventing or suppressing an increase in the device cost and an increase in the energy consumption.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3A

Figure 3B

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described. In the following description, the carbon dioxide recovery device will be abbreviated as the "recovery device", the carbon dioxide absorption tower will be abbreviated as the "absorption tower", the carbon dioxide stripping tower (sometimes referred to as the "carbon dioxide regeneration tower") will be abbreviated as the "stripping tower", and the carbon dioxide absorption solution may be abbreviated as the "solution". Further, the gas to be recovered of carbon dioxide by the recovery device (that is, the gas containing carbon dioxide) may be referred to as the "target gas".

[0012] A device or equipment that generates a gas containing carbon dioxide is applied to the target gas source 90. For example, as the target gas source 90, a metal melting furnace and a carburizing furnace that utilize the combustion heat of fossil fuels (that is, use fossil fuels as fuel) can be applied. In this case, the combustion exhaust gas of fossil fuels is the target gas. Further, an aqueous amine solution is applied to the solution.

[0013] <First Embodiment> <Configuration of the Recovery Device> FIG. 1 is a schematic diagram showing the configuration of the recovery device 10. The recovery device 10 includes an absorption tower 11, a stripping tower 12, a target gas introduction path 13, a target gas pump 14, a target gas discharge path 15, a first solution path 16, a second solution path 17, a first solution pump 18, a second solution pump 19, a solution heat exchanger 20, a reboiler 21, a carbon dioxide recovery path 22, a solution cooler 23, and a control device 24.

[0014] The absorption tower 11 is configured such that the solution absorbs carbon dioxide by bringing the solution into gas-liquid contact with the target gas (in other words, carbon dioxide is removed from the target gas). Inside the absorption tower 11, an upper target gas chamber 31, an upper absorption chamber 32, an intermediate solution chamber 33, an intermediate target gas chamber 34, and a lower absorption chamber 35 are provided in order from the upper side. Each stage of the absorption chambers 32, 35 is an example of the carbon dioxide absorption chamber of the present invention. Inside the absorption tower 11, a rotating body 36 that rotates by a driving power source 40 is arranged. The configuration of the absorption tower 11 will be described later.

[0015] The stripping tower 12 is configured such that carbon dioxide is stripped from the solution (such that a reaction occurs in which carbon dioxide is stripped from the solution) by heating the solution. Inside the stripping tower 12, an upper packing material 121 and a lower packing material 122 are arranged. Both the upper packing material 121 and the lower packing material 122 are members through which the solution can penetrate and gas (vapor and carbon dioxide) can pass. For example, porous metals or mesh-like members with a large specific surface area are applicable. The lower packing material 122 is a member for promoting gas-liquid contact between the solution and the vapor generated by heating the solution. The upper packing material 121 is arranged near the top of the stripping tower 12, and the lower packing material 122 is arranged below it. At the upper part of the stripping tower 12 and between the upper packing material 121 and the lower packing material 122, the other end of the first solution path 16 is connected, and at the bottom (or in the vicinity thereof) of the stripping tower 12 and below the lower packing material 122, the other end of the second solution path 17 is connected. Note that the configuration of the stripping tower 12 is not particularly limited, and a conventionally known configuration can be applied.

[0016] The target gas introduction path 13 is a path for feeding the target gas generated at the target gas source 90 to the absorption tower 11. One end of the target gas introduction path 13 is connected to the absorption tower 11, and the other end is connected to the target gas source 90. The target gas pump 14 is provided on the target gas introduction path 13. The target gas pump 14 is configured such that, when operating, it feeds (pressurizes) the target gas on the other end side of the target gas introduction path 13 (the target gas generated at the target gas source 90) to the one end side (absorption tower 11) of the target gas introduction path 13. A known electric air supply pump can be applied to the target gas pump 14.

[0017] The first solution path 16 is a path for feeding the solution from the absorption tower 11 to the stripping tower 12. One end of the first solution path 16 is connected to the absorption tower 11, and the other end is connected to the stripping tower 12. The first solution pump 18 is arranged on the first solution path 16. The first solution pump 18 is configured to feed the solution from the absorption tower 11 towards the stripping tower 12 when operating. The configuration of the first solution pump 18 is not particularly limited, and various conventionally known electric liquid delivery pumps can be applied. The solution heat exchanger 20 is provided on the first solution path 16 and the second solution path 17. The solution heat exchanger 20 is configured to perform heat exchange between the solution flowing through the first solution path 16 and the solution flowing through the second solution path 17. By performing heat exchange between the solution flowing through the first solution path 16 and the solution flowing through the second solution path 17 in the solution heat exchanger 20, the solution flowing through the first solution path 16 is heated, and the solution flowing through the second solution path 17 is cooled. Note that the configuration of the solution heat exchanger 20 is not limited, and various conventionally known heat exchangers can be applied.

[0018] The second solution path 17 is a path for feeding the solution from the stripping tower 12 to the absorption tower 11. One end of the second solution path 17 is connected to the absorption tower 11, and the other end of the second solution path 17 is connected to the bottom of the stripping tower 12. The second solution pump 19, the above-mentioned solution heat exchanger 20, and the solution cooler 23 are provided on the second solution path 17. The second solution pump 19 is configured to feed the solution accumulated inside (specifically, at the bottom) of the stripping tower 12 to the absorption tower 11 through the second solution path 17 when operating. A known electric liquid delivery pump can be applied to the second solution pump 19. The solution cooler 23 is configured to adjust the temperature (cool) of the solution fed to the absorption tower 11 to a temperature suitable for carbon dioxide absorption. Various known coolers can be applied to the solution cooler 23.

[0019] The target gas discharge path 15 is a path for discharging the target gas (sometimes referred to as off-gas) after carbon dioxide is absorbed in the absorption tower 11 to the outside of the absorption tower 11. One end of the target gas discharge path 15 is connected to the upper end of the absorption tower 11, and the other end is, for example, open to the atmosphere.

[0020] The reboiler 21 is configured to generate steam at a predetermined temperature (specifically, a temperature capable of heating the solution fed to the stripping tower 12 to a temperature at which a reaction for releasing carbon dioxide occurs) by heating the solution accumulated inside (bottom) of the stripping tower 12. The reboiler 21 is connected to the bottom of the stripping tower 12 via a first reboiler path 211 and a second reboiler path 212. Then, the reboiler 21 heats the solution flowing in through the first reboiler path 211 to generate steam. The steam generated in the reboiler 21 flows into the inside of the stripping tower 12 via the second reboiler path 212.

[0021] One end of the carbon dioxide recovery path 22 is connected above the upper packing 121 at or near the top of the stripping tower 12. On the carbon dioxide recovery path 22, a demister 221, a mixed gas cooler 222, and a gas-liquid separator 223 are arranged in order from the side closer to the stripping tower 12. The demister 221 is configured to remove the mist of the solution vapor from the mixed gas of the solution vapor and carbon dioxide and return the condensed water generated by the removed mist to the stripping tower 12. The mixed gas cooler 222 is configured to liquefy the solution vapor by cooling the mixed gas of the solution vapor and carbon dioxide. The gas-liquid separator 223 is configured to separate the solution and carbon dioxide generated by the liquefaction of the vapor. According to such a configuration, gaseous carbon dioxide can be separated from the mixed gas of the solution vapor and carbon dioxide flowing into the carbon dioxide recovery path 22. The separated carbon dioxide is discharged to the outside of the recovery device 10. The gas-liquid separator 223 and the stripping tower 12 are connected by a solution reflux path 224. This solution reflux path 224 is configured such that the solution separated from carbon dioxide in the gas-liquid separator 223 returns to the stripping tower 12.

[0022] The control device 24 is connected to the target gas pump 14, the first solution pump 18, the second solution pump 19, the reboiler 21, an intermediate solution pump 39 (described later), and a drive power source 40 of the rotating body 36, and can control these. The control device 24 is a device including a computer having a CPU, a RAM, a ROM, a storage device (memory device), and an I / F (interface). A computer program for controlling each part of the recovery device 10 is stored in advance in the ROM. Then, the CPU reads out the computer program stored in the ROM, expands it in the RAM (using the RAM as a work area), and executes it. Thereby, each part of the recovery device 10 is controlled.

[0023] <Basic operation of the recovery device> Next, the basic operation of the recovery device 10 will be described. The target gas generated in the target gas source 90 is fed to the absorption tower 11 by the operation of the target gas pump 14. Further, the solution temperature-controlled (cooled) to a temperature suitable for carbon dioxide absorption in the solution heat exchanger 20 and the solution cooler 23 flows into the inside of the absorption tower 11 through the second solution path 17 by the operation of the second solution pump 19. Then, in the absorption tower 11, the target gas and the solution come into gas-liquid contact, and the solution absorbs carbon dioxide contained in the target gas.

[0024] Then, the target gas from which carbon dioxide has been absorbed is discharged to the outside of the absorption tower 11 through the target gas discharge path 15. Further, the solution that has absorbed carbon dioxide is fed from the absorption tower 11 toward the stripping tower 12 by the operation of the first solution pump 18. Note that the solution flowing through the first solution path 16 is heated by heat exchange with the solution flowing through the second solution path 17 in the solution heat exchanger 20, and then flows into the inside of the stripping tower 12.

[0025] The solution flowing into the interior of the stripping tower 12 passes through the lower packing material 122 and accumulates at the bottom of the stripping tower 12. A part of the solution accumulated at the bottom of the stripping tower 12 flows into the reboiler 21 through the first reboiler path 211 and is heated in the reboiler 21. The vapor generated in the reboiler 21 flows into the interior of the stripping tower 12 through the second reboiler path 212, and then passes through the lower packing material 122 while rising from the bottom of the stripping tower 12. At this time, the vapor makes gas-liquid contact (countercurrent contact) with the solution flowing down from the top in the lower packing material 122. As a result, the solution flowing down through the lower packing material 122 is heated, and carbon dioxide is dissipated from the solution.

[0026] The mixture of carbon dioxide dissipated from the solution and the vapor remaining without liquefaction passes through the upper packing material 121 and flows into the carbon dioxide recovery path 22 from the top of the stripping tower 12. The upper packing material 121 is a porous or mesh-like member. Therefore, when the mixture passes through the upper packing material 121, the mist contained in the mixture is removed to some extent.

[0027] In the demister 221 provided in the carbon dioxide recovery path 22, the vapor mist is removed from the mixture flowing into the carbon dioxide recovery path 22. Further, the mixture is cooled in the mixture cooler 222, so that the vapor condenses (liquefies). Then, in the gas-liquid separator 223, it is separated into carbon dioxide as a gas and a solution as a liquid. The carbon dioxide separated in the gas-liquid separator 223 is discharged to the outside through the carbon dioxide recovery path 22. That is, carbon dioxide is recovered through the carbon dioxide recovery path 22. On the other hand, the solution separated in the gas-liquid separator 223 returns to the stripping tower 12 through the solution reflux path 224 and flows down through the upper packing material 121. Since the upper packing material 121 is cooled thereby, the condensation of the vapor contained in the mixture passing through the upper packing material 121 is promoted.

[0028] The solution accumulated at the bottom of the stripping tower 12 is fed from the stripping tower 12 to the absorption tower 11 through the second solution path 17 by the operation of the second solution pump 19. Then, the solution flowing through the second solution path 17 is cooled by exchanging heat with the solution flowing through the first solution path 16 in the solution heat exchanger 20, and is further cooled by releasing heat in the solution cooler 23. As a result, the solution reaches a temperature suitable for the absorption of carbon dioxide. Then, the solution flows into the upper absorption chamber 32 of the absorption tower 11.

[0029] In this way, the solution circulates in the order of the absorption tower 11, the first solution path 16, the stripping tower 12, and the second solution path 17 by the operations of the first solution pump 18 and the second solution pump 19. And while circulating, the solution repeatedly undergoes the reaction of absorbing carbon dioxide contained in the target gas in the absorption tower 11 and releasing the absorbed carbon dioxide in the stripping tower 12. The carbon dioxide released from the solution in the stripping tower 12 is discharged from the recovery device 10 through the carbon dioxide recovery path 22.

[0030] <Configuration of Absorption Tower> Next, the configuration of the absorption tower 11 will be described. FIG. 2 is a cross-sectional view showing the configuration of the absorption tower 11. In FIG. 2, above the absorption tower 11 and the rotating body 36 is indicated by the arrow Up, and below is indicated by the arrow Dw. As shown in FIG. 2, inside the absorption tower 11, an upper target gas chamber 31, an upper absorption chamber 32, an intermediate solution chamber 33, an intermediate target gas chamber 34, and a lower absorption chamber 35 are provided in order from the upper side. Also, a rotating body 36 is rotatably arranged inside the absorption tower 11. The rotating body 36 rotates about an axis (rotation center line) substantially parallel to the vertical direction by the driving force of a driving power source 40 arranged outside the absorption tower 11 (the lower side in FIG. 2). The driving power source 40 is controlled by the control device 24. Note that the driving power source 40 only needs to be able to output rotational power, and the configuration of the driving power source 40 is not particularly limited. Various known motors can be applied to the driving power source 40.

[0031] The upper target gas chamber 31 is provided so as to be adjacent to the upper side of the upper absorption chamber 32. One end of the target gas discharge path 15 is connected to the upper target gas chamber 31.

[0032] The upper absorption chamber 32 is a space through which the target gas and the solution can pass. Inside the upper absorption chamber 32, the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52 of the rotating body 36 are accommodated. The upper absorption chamber 32 is configured to be able to store the solution at the bottom. And the upper absorption chamber 32 communicates with the upper target gas chamber 31 so that the target gas can flow through the upper shaft part 51 provided on the rotating body 36. Also, the upper absorption chamber 32 communicates with the second solution path 17 through the inner shaft part 512 of the upper shaft part 51 of the rotating body 36 described later.

[0033] The intermediate solution chamber 33 is a space provided adjacent to the lower side of the upper absorption chamber 32. The intermediate solution chamber 33 is configured to be able to store the solution. The upper absorption chamber 32 and the intermediate solution chamber 33 are connected by an intermediate solution path 38. An intermediate solution pump 39 is provided on the intermediate solution path 38 (omitted in FIG. 2. Refer to FIG. 1). By operating, the intermediate solution pump 39 can feed the solution accumulated at the bottom of the upper absorption chamber 32 to the intermediate solution chamber 33 through the intermediate solution path 38. The intermediate solution pump 39 is controlled by the control device 24. Note that the configuration of the intermediate solution pump 39 is not particularly limited, and various known electric liquid feed pumps are applicable.

[0034] The intermediate target gas chamber 34 is provided so as to be adjacent to the lower side of the intermediate solution chamber 33 (in other words, between the lower absorption chamber 35 and the intermediate solution chamber 33). The intermediate target gas chamber 34 and the upper absorption chamber 32 communicate with each other so that the target gas can flow through an intermediate target gas path 37.

[0035] The lower absorption chamber 35 is a space through which the target gas and the solution can pass. Inside the lower absorption chamber 35, the lower gas-liquid contact part 56 and the lower gas-liquid separation part 55 of the rotating body 36 are accommodated. The lower absorption chamber 35 is configured to be able to store the solution at the bottom. One end of the target gas introduction path 13 is connected to the lower absorption chamber 35. Further, the lower absorption chamber 35 and the intermediate solution chamber 33 communicate with each other such that the solution can flow through the intermediate shaft part 54 of the rotating body 36, which will be described later. Furthermore, the lower absorption chamber 35 and the intermediate target gas chamber 34 communicate with each other such that the target gas can flow through the intermediate shaft part 54 of the rotating body 36.

[0036] In this way, the upper absorption chamber 32 and the lower absorption chamber 35 are connected in series via the intermediate target gas chamber 34 and the intermediate target gas path 37 so that the target gas fed from the outside passes in a predetermined one direction (specifically, the direction from the lower absorption chamber 35 to the upper absorption chamber 32). Also, the upper absorption chamber 32 and the lower absorption chamber 35 are connected in series via the intermediate solution chamber 33 and the intermediate solution path 38 so that the solution fed from the outside passes in a direction opposite to the predetermined one direction (specifically, the direction from the upper absorption chamber 32 to the lower absorption chamber 35).

[0037] <Configuration of gas-liquid contact part and gas-liquid separation part> Next, the configurations of the gas-liquid contact parts 53 and 56 and the gas-liquid separation parts 52 and 55 of each stage provided on the rotating body 36 will be described. The rotating body 36 includes an upper gas-liquid contact part 53 and an upper gas-liquid separation part 52 disposed in the upper absorption chamber 32, and a lower gas-liquid contact part 56 and a lower gas-liquid separation part 55 disposed in the lower absorption chamber 35. In addition, the rotating body 36 includes an upper shaft part 51 provided above the upper gas-liquid contact part 53, an intermediate shaft part 54 provided between the upper gas-liquid contact part 53 and the lower gas-liquid contact part 56, and a lower shaft part 57 provided below the lower gas-liquid contact part 56. The upper shaft part 51, the intermediate shaft part 54, and the lower shaft part 57 are rotatably supported by bearings or the like with respect to the absorption tower 11. The upper shaft part 51 forms a solution path for supplying a solution to the upper gas-liquid contact part 53 (upper absorption chamber 32), and forms a target gas path for discharging the target gas that has passed through the upper gas-liquid contact part 53 from the upper absorption chamber 32. The intermediate shaft part 54 forms a solution path for supplying a solution to the lower gas-liquid contact part 56, and forms a target gas path for discharging the target gas that has passed through the lower gas-liquid contact part 56 (lower absorption chamber 35) from the lower absorption chamber 35.

[0038] The gas-liquid contact parts 53 and 56 of each stage are parts for promoting gas-liquid contact between the solution and the target gas. It can also be said that the gas-liquid contact parts 53 and 56 of each stage are parts for increasing the contact area between the solution and the target gas. The gas-liquid separation parts 52 and 55 of each stage are parts configured to remove the solution mist contained in the target gas that has passed through the gas-liquid separation parts 52 and 55 of each stage. FIG. 3A is a cross-sectional view showing the configuration of the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52. In FIG. 3A, the upper side of the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52 is indicated by an arrow Up, and the lower side is indicated by an arrow Dw (the same applies to FIG. 3B). Note that the configurations of the lower gas-liquid contact part 56 and the lower gas-liquid separation part 55 are substantially the same as those of the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52, so the illustration is omitted.

[0039] The gas-liquid contact parts 53 and 56 of each stage are configured such that the solution can penetrate and diffuse inside, and the target gas can pass through the inside. Specifically, the gas-liquid contact parts 53 and 56 of each stage include a plurality (in other words, a large number) of packing materials 60 and a container 61 that houses the plurality of packing materials 60. As the packing material 60, a member with a large specific surface area is applied. For example, as the packing material 60, a formed body obtained by forming a metal mesh into a predetermined shape (for example, a round bar shape or a spherical shape) is applied. The container 61 has a substantially cylindrical shape with a hollow inside as a whole. However, the upper surface of the container 61 (in other words, the upper end of the internal space of the container 61) has a shape that becomes lower as it goes radially outward from the rotation center.

[0040] The container 61 of the gas-liquid contact parts 53 and 56 of each stage includes a side plate part 62, a bottom plate part 63, and a lid part 64. The side plate part 62 is a substantially cylindrical member with openings at both ends in the axial direction (vertical direction). The side plate part 62 is configured such that the target gas and the solution can pass through both the inner peripheral side and the outer peripheral side. For example, the side plate part 62 is formed of punched metal provided with a large number of openings (through holes).

[0041] The bottom plate part 63 is a substantially disc-shaped member attached to the lower side of the side plate part 62 so as to close the lower opening of the side plate part 62. The bottom plate part 63 is configured such that gas and liquid can pass through in the vertical direction (thickness direction). For example, the bottom plate part 63 is also formed of punched metal or the like, similar to the side plate part 62. The side plate part 62 and the bottom plate part 63 are examples of the container body of the present invention. That is, by attaching the bottom plate part 63 to the lower side of the side plate part 62, a substantially cylindrical container body with an upper opening is formed.

[0042] The lid portion 64 is a member attached to the upper side of the side plate portion 62 so as to close the upper opening of the side plate portion 62. It can also be said that the lid portion 64 is a member that closes the upper opening of the container body formed by the side plate portion 62 and the bottom plate portion 63. The lid portion 64 is provided with an inner shaft portion exposure hole 641 provided at the rotation center portion, a ventilation portion 642 provided so as to surround the inner shaft portion exposure hole 641 on the outer periphery of the inner shaft portion exposure hole 641, and a non-ventilation portion 643 provided so as to surround the ventilation portion 642 on the outer peripheral side of the ventilation portion 642. The inner shaft portion exposure hole 641 is an opening for exposing the lower ends of the inner shaft portions 512 and 542, which will be described later, to the inside of the container 61. The ventilation portion 642 is a portion configured to allow the target gas to pass in the vertical direction. For example, the ventilation portion 642 is provided with a plurality of openings penetrating in the vertical direction.

[0043] The non-ventilation portion 643 is a portion having no air permeability. It can also be said that the non-ventilation portion 643 is a portion that does not allow the passage of the target gas in the vertical direction. The non-ventilation portion 643 has a shape in which the height decreases from the side closer to the rotation center portion toward the side farther away. In FIG. 3A, the non-ventilation portion 643 is shown having a configuration including a substantially cylindrical tubular portion and a substantially frustum-shaped inclined portion extending radially outward and downward from the lower end of the tubular portion. And the substantially frustum-shaped inclined portion is located below the lower ends of the inner shaft portions 512 and 542. Note that the non-ventilation portion 643 may have a shape in which the height decreases toward the outside from the center in the radial direction of the surface forming the inner peripheral surface of the container 61 (that is, the inner peripheral surface of the tubular portion and the lower surface of the inclined portion), and the shape of the surface forming the outer peripheral surface of the container 61 is not particularly limited.

[0044] Then, the internal space of the container 61 is filled with a plurality of fillers 60. Note that it is preferable that the plurality of fillers 60 are filled in the entire internal space of the container 61 (in other words, so that no gap is formed between the inner peripheral surface of the container 61 and the aggregate of the fillers 60 to be filled). In particular, it is preferable that no gap exists between the aggregate of the fillers 60 and the inner peripheral surface of the non-ventilation portion 643. For this reason, the upper surface of the aggregate of the fillers 60 filled in the internal space of the container 61 has a shape that becomes lower as it goes from the rotation center toward the outer side in the radial direction, similar to the shape of the lid portion 64 of the container 61 (it can also be said that it has a portion that becomes lower as it goes from the rotation center toward the outer side in the radial direction).

[0045] On the upper side of each stage of gas-liquid contact portions 53, 56, each stage of gas-liquid separation portions 52, 55 are attached. Each stage of gas-liquid separation portions 52, 55 has a dome-shaped configuration with an opening at the lower side and is attached so as to cover the ventilation portion 642 of the lid portion 64. For this reason, a cavity (hereinafter, may be referred to as the internal space of each stage of gas-liquid separation portions 52, 55) is formed above the ventilation portion 642 of the lid portion 64 of each stage of gas-liquid contact portions 53, 56 by each stage of gas-liquid separation portions 52, 55.

[0046] A through-hole penetrating in the vertical direction is provided at the rotation center portion of each stage of gas-liquid separation portions 52, 55. And the lower end portion of the upper shaft portion 51 of the rotating body 36 is inserted into the through-hole of the upper stage of gas-liquid separation portion 52 and is located in the internal space of the upper stage of gas-liquid separation portion 52. As shown in FIGS. 2 and 3A, both the upper shaft portion 51 and the intermediate shaft portion 54 of the rotating body 36 have a double-tube structure. Specifically, the upper shaft portion 51 and the intermediate shaft portion 54 of the rotating body 36 include outer shaft portions 511, 541 and inner shaft portions 512, 542 coaxially arranged inside these outer shaft portions 511, 541. The inner shaft portions 512, 542 are examples of the carbon dioxide absorption solution supply portion of the present invention. The inner shaft portions 512, 542 of the upper shaft portion 51 and the intermediate shaft portion 54 form a path for the solution and are configured such that the solution flows out from the lower end.

[0047] And the lower end of the inner shaft portion 512 of the upper shaft portion 51 is exposed to the internal space of the container 61 through the inner shaft portion exposure hole 641 provided in the lid portion 64 of the upper gas-liquid contact portion 53. For this reason, the solution that has passed through the inner shaft portion 512 of the upper shaft portion 51 is supplied (flows in) to the aggregate of the packing material 60 filled inside the container 61 of the upper gas-liquid contact portion 53. Similarly, the lower end of the inner shaft portion 542 of the intermediate shaft portion 54 is exposed to the internal space of the container 61 through the inner shaft portion exposure hole 641 provided in the lid portion 64 of the lower gas-liquid contact portion 56. For this reason, the solution that has passed through the inner shaft portion 542 of the intermediate shaft portion 54 is supplied (flows in) to the aggregate of the packing material 60 filled inside the container 61 of the lower gas-liquid contact portion 56.

[0048] Note that the lower ends of the inner shaft portions 512 and 542 have a simple cylindrical configuration. For this reason, when there is no aggregate of the packing material 60 below the lower ends of the inner shaft portions 512 and 542, the solution flowing out from the lower ends of the inner shaft portions 512 and 542 flows downward due to gravity. And since the upper shaft portion 51 and the intermediate shaft portion 54 are arranged coaxially with the gas-liquid contact portions 53 and 56 of each stage, the solution that has passed through the inner shaft portions 512 and 542 flows down to the rotation center portion of the upper surface of the aggregate of the packing material 60 filled inside the container 61. Also, the height of the lower ends of the inner shaft portions 512 and 542 is higher than the lower end height of the non-venting portion 643. And it is preferable that the height of the lower ends of the inner shaft portions 512 and 542 is as high as possible. For example, the height of the lower surface of the venting portion 642, or the same height as the portion located at the highest position among the non-venting portions 643 can be applied.

[0049] Further, the outer shaft portion 511 and the inner shaft portion 512 of the upper shaft portion 51 form a path for discharging the target gas from the upper absorption chamber 32. Specifically, the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512 is the path for discharging the target gas from the upper absorption chamber 32. And, at the lower end portion of the outer shaft portion 511 of the upper shaft portion 51, which is located in the internal space of the upper gas-liquid separation portion 52, a target gas path hole 513 is provided, which is a through hole communicating the outside and the inside of the outer shaft portion 511 (specifically, the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512). For this reason, the target gas that has flowed into the internal space of the upper gas-liquid separation portion 52 through the vent portion 642 of the lid portion 64 of the upper gas-liquid contact portion 53 passes through the internal space of the upper gas-liquid separation portion 52, flows into the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512 from the target gas path hole 513, and is discharged from the upper absorption chamber 32 by passing through the said space.

[0050] Similarly, the outer shaft portion 541 and the inner shaft portion 542 of the intermediate shaft portion 54 form a path for discharging the target gas from the lower absorption chamber 35. At the lower end portion of the outer shaft portion 541 of the intermediate shaft portion 54, which is located in the internal space of the lower gas-liquid separation portion 55, an upstream target gas path hole 544 is provided, which is a through hole communicating the outside and the inside of the outer shaft portion 541. Also, in the portion of the outer shaft portion 541 of the intermediate shaft portion 54 that is located inside the intermediate target gas chamber 34, a downstream target gas path hole 545 is provided, which is a through hole communicating the outside and the inside of the outer shaft portion 541. For this reason, the target gas that has flowed into the internal space of the lower gas-liquid separation portion 55 through the vent portion 642 of the lid portion 64 of the lower gas-liquid contact portion 56 passes through the internal space of the lower gas-liquid separation portion 55, flows into the space between the inner peripheral surface of the outer shaft portion 541 and the outer peripheral surface of the inner shaft portion 542 from the upstream target gas path hole 544, and is discharged from the lower absorption chamber 35 by passing through the said space.

[0051] According to such a configuration, since the solution can be diffused and permeated throughout the aggregate of the filler 60, the absorption efficiency of carbon dioxide can be enhanced. That is, the solution flowing into the inside of the aggregate of the filler 60 at each stage of the gas-liquid contact portions 53, 56 from the lower end portions of the inner shaft portions 512, 542 diffuses and permeates from the rotation center portion on the upper surface of the aggregate of the filler 60 toward the outer side and the lower side in the radial direction of rotation due to the centrifugal force and the gravitational force caused by the rotation of the rotating body 36. For this reason, when the container 61 has a simple cylindrical shape, it is difficult for the solution to permeate into the region near the upper surface and near the outer peripheral portion in the radial direction (hereinafter referred to as the upper corner region) of the aggregate of the filler 60, and the amount of the solution contained in the aggregate of the filler 60 is small. Then, since the target gas flowing in from the outer peripheral surface (side surface) of the container 61 and passing through the upper corner region has little opportunity to contact the solution, the carbon dioxide contained in the target gas flows out upward from the lid portion 64 of the container 61 at each stage without being sufficiently absorbed by the solution and flows into the gas-liquid separation portions 52, 55 at each stage. In particular, since the upper corner region has less diffused and permeated solution compared to other regions, the target gas is more likely to pass through the upper corner region compared to other regions. For this reason, the passage of the target gas tends to concentrate in the upper corner region, and as a result, the absorption efficiency of carbon dioxide decreases.

[0052] On the other hand, according to the gas-liquid contact portions 53, 56 at each stage of the recovery device 10 according to the present embodiment, the lid portion 64 of the container 61 includes a portion that becomes lower as it goes from the rotation center portion toward the outer side in the radial direction. For this reason, an upper corner region with little permeating solution as described above is not formed in the upper part of the aggregate of the filler 60 filled inside the container 61. For this reason, it is possible to prevent or suppress the target gas flowing into the inside of the container 61 from flowing out to the outside of the container 61 without sufficiently contacting the solution, and thus it is possible to prevent or suppress a decrease in the absorption efficiency of carbon dioxide (or to improve the absorption efficiency of carbon dioxide).

[0053] Furthermore, according to the present embodiment, compared with the configuration in which the container 61 has a simple cylindrical shape, the internal space of the container 61 can be reduced, so that the volume (mass) of the filler 60 filled in the container 61 can be reduced. Therefore, since the mass of the rotating body 36 can be reduced, it is possible to reduce the energy consumption of the driving force source 40 for rotating the rotating body 36. In addition, since it is possible to reduce the load applied to the driving force source 40 and the reduction applied to the absorption tower 11 due to the rotation of the rotating body 36, it is possible to extend the maintenance cycle of the recovery device 10 and improve the reliability of the recovery device 10.

[0054] Also, the reaction in which the amine aqueous solution, which is a solution, absorbs carbon dioxide is an exothermic reaction, and the higher the absorption efficiency of carbon dioxide, the greater the amount of heat generated by the solution. Therefore, according to the present embodiment, by increasing the absorption efficiency of carbon dioxide, the temperature of the solution discharged from the absorption tower 11 (fed to the stripping tower 12) can be increased. Therefore, since the amount of heat added to the solution in the stripping tower 12 can be reduced (the output of the reboiler 21 can be lowered), it is possible to reduce the energy consumption of the recovery device 10.

[0055] Also, according to the present embodiment, compared with the configuration in which the container 61 has a simple cylindrical shape, the volume of the "region through which the target gas passes" of the gas-liquid contact portions 53 and 56 of each stage is reduced. Therefore, compared with the configuration having a simple cylindrical shape, the pressure loss when passing through the gas-liquid contact portions 53 and 56 of each stage can be reduced, so that the load on the target gas pump 14 can be reduced.

[0056] In the above embodiment, the lower surface of the non-ventilation portion 643 is shown as an inclined surface whose height smoothly decreases as it goes toward the outer peripheral side. However, the present invention is not limited to such a configuration. For example, the lower surface of the non-ventilation portion 643 may be a stepped surface whose height decreases stepwise as it goes toward the outer peripheral side. Further, in the above embodiment, the lower surface of the ventilation portion 642 is shown as a substantially horizontal plane. However, the lower surface of the ventilation portion 642 may also be configured such that its height decreases as it goes toward the outer peripheral side. In short, the inner peripheral surface of the lid portion 64 has a portion whose height decreases as it goes away from the rotation center portion. In other words, it is sufficient that the upper surface of the aggregate of the filler 60 filled in the container 61 has a portion whose height decreases as it goes away from the rotation center portion.

[0057] <Operation of Absorption Tower> Here, the operation of the absorption tower 11 will be described. As shown in FIG. 2, the rotating body 36 includes, in order from the upper side, an upper shaft portion 51, an upper gas-liquid separation portion 52, an upper gas-liquid contact portion 53, an intermediate shaft portion 54, a lower gas-liquid separation portion 55, a lower gas-liquid contact portion 56, and a lower shaft portion 57. Further, the upper shaft portion 51, the intermediate shaft portion 54, and the lower shaft portion 57 are rotatably supported by the absorption tower 11 via bearings. A driving power source 40 is connected to the lower shaft portion 57. And the respective parts of the rotating body 36 are arranged coaxially and rotate integrally.

[0058] The upper shaft portion 51 is a portion located at the upper end of the rotating body 36. As described above, the upper shaft portion 51 has a double-tube structure. The inner shaft portion 512 of the upper shaft portion 51 is a portion configured in a cylindrical shape with both the upper end and the lower end open, and forms a path for the solution. The upper end portion of the inner shaft portion 512 of the upper shaft portion 51 protrudes upward from the upper end of the outer shaft portion 511 of the upper shaft portion 51 and is located outside the upper target gas chamber 31. And one end of the second solution path 17 is connected to the upper end portion of the inner shaft portion 512 of the upper shaft portion 51. For this reason, the solution flows into the inner shaft portion 512 of the upper shaft portion 51 by the operation of the second solution pump 19, and the solution that has passed through the inner shaft portion 512 of the upper shaft portion 51 is supplied to the upper gas-liquid contact portion 53.

[0059] The solution that has passed through the inside of the upper gas-liquid contact part 53 flows down (drops) from the outer peripheral surface and the lower surface of the upper gas-liquid contact part 53. Then, the solution that has flowed down from the upper gas-liquid contact part 53 accumulates at the bottom of the upper absorption chamber 32. The solution that has accumulated at the bottom of the upper absorption chamber 32 is fed to the intermediate solution chamber 33 through the intermediate solution path 38 by the operation of the intermediate solution pump 39.

[0060] The intermediate shaft part 54 is a hollow shaft-shaped part provided between the upper gas-liquid contact part 53 and the lower gas-liquid contact part 56. The upper part of the intermediate shaft part 54 is located inside the upper absorption chamber 32. And the upper end part of the intermediate shaft part 54 is joined to the lower part of the upper gas-liquid contact part 53. The lower end part of the intermediate shaft part 54 and its vicinity are located inside the lower absorption chamber 35. And, the lower gas-liquid contact part 56 is arranged below the intermediate shaft part 54. Also, the lower end part of the intermediate shaft part 54 and its vicinity are located in the internal space of the lower gas-liquid separation part 55. The vertical intermediate part of the intermediate shaft part 54 is located inside the intermediate solution chamber 33 and the intermediate target gas chamber 34.

[0061] The lower part of the intermediate shaft portion 54 (the portion located inside the intermediate target gas chamber 34 and inside the lower absorption chamber 35) has a double-tube structure. Specifically, the intermediate shaft portion 54 includes a substantially cylindrical outer shaft portion 541 and an inner shaft portion 542, and the inner shaft portion 542 is disposed in the lower part of the internal space of the outer shaft portion 541. Note that the upper and lower ends of the inner shaft portion 542 are open, and the internal space of the outer shaft portion 541 in the upper part of the intermediate shaft portion 54 communicates with the internal space of the inner shaft portion 542 in the lower part. A solution passage hole 543 is provided in the intermediate solution chamber 33 and at a position above the upper end of the inner shaft portion 542 in the outer shaft portion 541 of the intermediate shaft portion 54. The solution passage hole 543 is a through hole that allows the solution to pass through and communicate the outside and the internal space of the outer shaft portion 541 of the intermediate shaft portion 54. Therefore, the solution accumulated in the intermediate solution chamber 33 flows into the internal space of the outer shaft portion 541 of the intermediate shaft portion 54 through the solution passage hole 543 provided in the intermediate shaft portion 54, further flows down through the internal space of the inner shaft portion 542, and flows out from the lower end of the inner shaft portion 542. Thus, in the portion of the intermediate shaft portion 54 located inside the intermediate solution chamber 33, the outer shaft portion 541 forms a path for the solution, and in the middle and lower portions in the vertical direction of the intermediate shaft portion 54, the inner shaft portion 542 (specifically, the internal space of the inner shaft portion 542) forms a path for the solution.

[0062] Below the intermediate shaft portion 54, a lower gas-liquid contact portion 56 is disposed. Further, the vicinity of the lower end portion of the intermediate shaft portion 54 is located in the internal space of the lower gas-liquid separation portion 55. Therefore, the solution flowing out from the lower end of the inner shaft portion 542 of the intermediate shaft portion 54 is supplied to the lower gas-liquid contact portion 56 from the rotation center portion of the upper surface of the lower gas-liquid contact portion 56. The solution supplied to the lower gas-liquid contact portion 56 diffuses and penetrates radially outward and downward from the approximate rotation center of the upper surface by the centrifugal force and gravity of the rotation of the lower gas-liquid contact portion 56. For this reason, similar to the upper gas-liquid contact portion 53, the solution diffuses over substantially the entire lower gas-liquid contact portion 56. Then, a film (liquid film) of the solution is formed on the surface of the lower gas-liquid contact portion 56 (specifically, the surface of the aggregate of the packing materials 60 accommodated in the container 61). The solution that has diffused and penetrated into the lower gas-liquid contact portion 56 flows down (falls) from the outer peripheral surface and the lower surface of the lower gas-liquid contact portion 56. The solution that has flowed down from the outer peripheral surface and the lower surface of the lower gas-liquid contact portion 56 accumulates at the bottom of the lower absorption chamber 35. The solution accumulated at the bottom of the lower absorption chamber 35 is discharged from the lower absorption chamber 35 by the operation of the first solution pump 18 and fed toward the stripping tower 12.

[0063] One end of the target gas introduction path 13 is connected to the lower absorption chamber 35. Therefore, the target gas fed from the target gas source 90 by the operation of the target gas pump 14 flows into the lower absorption chamber 35. The target gas that has flowed into the lower absorption chamber 35 flows into the lower gas-liquid contact portion 56 from the lower surface and the outer peripheral surface thereof, and flows into the internal space of the lower gas-liquid separation portion 55 from the upper surface (vent portion 642 of the lid portion 64) of the lower gas-liquid contact portion 56.

[0064] In a portion of the intermediate shaft portion 54 that is located inside the lower absorption chamber 35, an upstream target gas path hole 544 is provided, and in a portion that is located inside the intermediate target gas chamber 34, a downstream target gas path hole 545 is provided. Both the upstream target gas path hole 544 and the downstream target gas path hole 545 are through holes that allow the target gas to communicate between the outside of the outer shaft portion 541 and the internal space of the outer shaft portion 541 (the space between the outer shaft portion 541 and the inner shaft portion 542) so that the target gas can pass through. For this reason, the target gas that has passed through the internal space of the lower gas-liquid separation portion 55 flows into the internal space of the outer shaft portion 541 of the intermediate shaft portion 54 (more specifically, the space between the inner peripheral surface of the outer shaft portion 541 and the outer peripheral surface of the inner shaft portion 542) through the upstream target gas path hole 544, passes through this internal space, and flows into the inside of the intermediate target gas chamber 34 through the downstream target gas path hole 545. Note that the upper and lower ends of the space between the outer shaft portion 541 and the inner shaft portion 542 are closed. In the lower portion of the intermediate shaft portion 54 (the portion located inside the intermediate target gas chamber 34 and the lower absorption chamber 35), the outer shaft portion 541 (specifically, the space between the inner peripheral surface of the outer shaft portion 541 and the outer peripheral surface of the inner shaft portion 542) forms a path for the target gas.

[0065] The target gas that has flowed into the intermediate target gas chamber 34 flows into the upper absorption chamber 32 through the intermediate target gas path 37. Then, the target gas that has flowed into the inside of the upper absorption chamber 32 flows into the inside of the upper gas-liquid contact portion 53 from the outer peripheral surface and the lower surface of the upper gas-liquid contact portion 53, passes through the inside of the upper gas-liquid contact portion 53, and flows into the internal space of the upper gas-liquid separation portion 52 from the upper surface (vent portion 642 of the lid portion 64) of the upper gas-liquid contact portion 53.

[0066] The vicinity of the lower end of the upper shaft portion 51 is located in the internal space of the upper gas-liquid separation portion 52. And, a target gas passage hole 513 is provided in a portion of the outer shaft portion 511 of the upper shaft portion 51 that is located in the internal space of the upper gas-liquid separation portion 52. The target gas passage hole 513 is a through hole (opening) that allows gas to pass through between the internal space of the outer shaft portion 511 (that is, the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512) and the outside (that is, the inside of the upper gas-liquid separation portion 52). The upper end of the outer shaft portion 511 of the upper shaft portion 51 is located inside the upper target gas chamber 31, and the inside of the outer shaft portion 511 (the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512) communicates with the inside of the upper target gas chamber 31.

[0067] Therefore, the target gas that has flowed into the internal space of the upper gas-liquid separation portion 52 flows into the internal space of the outer shaft portion 511 (the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512) through the target gas passage hole 513, passes through the internal space of the outer shaft portion 511, and flows into the inside of the upper target gas chamber 31 from the upper end of the outer shaft portion 511. In this way, the outer shaft portion 511 of the upper shaft portion 51 (more specifically, the space between the inner peripheral surface of the outer shaft portion 511 and the outer peripheral surface of the inner shaft portion 512) forms a path for the target gas (off-gas). And, the target gas flows out (is discharged) to the outside of the absorption tower 11 through the target gas discharge path 15.

[0068] The lower shaft portion 57 is a substantially cylindrical or substantially round bar-shaped portion. The lower end portion of the lower shaft portion 57 protrudes outside the absorption tower 11 and is connected to the driving power source 40 so that rotational power is transmitted from the driving power source 40.

[0069] In this way, in the gas-liquid contact parts 53 and 56 of each stage disposed in the absorption chambers 32 and 35 of each stage, the solution and the target gas are in gas-liquid contact, whereby the carbon dioxide contained in the target gas is absorbed by the solution. For this reason, the concentration of carbon dioxide contained in the target gas gradually decreases each time it passes through the lower absorption chamber 35 and the upper absorption chamber 32. On the other hand, while the solution flows through the upper absorption chamber 32 and the lower absorption chamber 35, the absorption ratio of carbon dioxide in the solution gradually increases (the loading value of carbon dioxide increases). That is, the solution changes from a carbon dioxide-lean state to a carbon dioxide-rich state.

[0070] As described above, in the absorption tower 11, the solution fed from the stripping tower 12 via the second solution path 17 passes through the upper absorption chamber 32, the intermediate target gas chamber 34, and the lower absorption chamber 35 in this order in one direction, and is discharged from the lower absorption chamber 35 to the outside of the absorption tower 11 (specifically, fed to the stripping tower 12). Further, in the absorption tower 11, the target gas fed from the target gas source 90 through the target gas introduction path 13 passes through the lower absorption chamber 35, the intermediate target gas chamber 34, the upper absorption chamber 32, and the upper target gas chamber 31 in the direction opposite to the one direction in this order, and is discharged from the upper target gas chamber 31 to the outside of the absorption tower 11.

[0071] <Second Embodiment> Next, the second embodiment will be described. FIG. 3B is a cross-sectional view showing the configuration of the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52 of the recovery device 10 according to the second embodiment. Note that the configurations of the lower gas-liquid contact part 56 and the lower gas-liquid separation part 55 are substantially the same as those of the upper gas-liquid contact part 53 and the upper gas-liquid separation part 52, and thus the illustration thereof is omitted. Further, the same configuration as that of the first embodiment can be applied to the configuration of the recovery device 10 according to the second embodiment other than the gas-liquid contact parts 53 and 56 of each stage.

[0072] The bottom plate portions 63 of the gas-liquid contact portions 53 and 56 of each stage are configured such that the height increases from the outer peripheral side toward the rotation center portion. In other words, the height of the region of the bottom plate portion 63 at the rotation center portion is higher than the height of the region at the outer peripheral side. For this reason, the volume (mass) of the packing material 60 filled inside the container 61 is smaller compared to the gas-liquid contact portions 53 and 56 of the first embodiment. Otherwise, the same configuration as that of the first embodiment is applied. According to such a configuration, the same effects as those of the first embodiment can be achieved. Furthermore, according to such a configuration, the weight of the gas-liquid contact portions 53 and 56 of each stage can be reduced compared to the first embodiment.

[0073] That is, the solution flowing down from the inner shaft portions 512 and 542 diffuses and penetrates from the rotation center portion of the upper surface of the aggregate of the packing material 60 toward the outer side and downward in the radial direction of rotation due to the centrifugal force and gravity caused by the rotation of the rotating body 36. For this reason, the region (substantially conical region) at the lower part and near the rotation center portion of the aggregate of the packing material 60 contributes less to the improvement of the carbon dioxide absorption efficiency by the solution compared to other regions.

[0074] Therefore, as shown in FIG. 3B, by configuring the bottom plate portions 63 of the gas-liquid contact portions 53 and 56 of each stage such that the height increases from the outer peripheral side toward the rotation center portion (in other words, by configuring the bottom plate portion 63 such that the height of the region at the rotation center portion is higher than the height of the region at the outer peripheral side), the volume (mass) of the aggregate of the packing material 60 can be reduced without reducing the carbon dioxide absorption efficiency. And according to such a configuration, since the mass of the rotating body 36 can be further reduced compared to the first embodiment, the load applied to each part of the absorption tower 11 can be made even smaller. Therefore, it is possible to improve the reliability of the recovery device 10 and to extend the maintenance cycle of the recovery device 10.

[0075] Note that the specific shape of the bottom plate portion 63 is not particularly limited. For example, the upper surface of the bottom plate portion 63 may be configured such that the height increases stepwise in a stepped manner from the outer peripheral side toward the rotation center portion.

[0076] <Summary of Embodiments> The carbon dioxide recovery device 10 according to each embodiment includes: a carbon dioxide absorption tower 11 configured to absorb carbon dioxide contained in a gas (target gas) fed from a gas source (target gas source 90) into a carbon dioxide absorption solution; a gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage) disposed in a carbon dioxide absorption chamber (absorption chambers 32, 35 at each stage) provided inside the carbon dioxide absorption tower 11, through which the carbon dioxide absorption solution can penetrate and the gas (target gas) can pass, and configured to rotate about an axis substantially parallel to the vertical direction by the driving force of a driving force source 40; a carbon dioxide absorption solution supply part (inner shaft parts 512, 542) configured to supply the carbon dioxide absorption solution to the rotation center part on the upper surface of the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage); and the upper surface of the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage) has a portion where the height decreases as it moves away from the rotation center part.

[0077] According to such a configuration, the carbon dioxide absorption solution supplied to the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage) penetrates radially outward and downward from the rotation center part at the upper part of the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage) by the centrifugal force and gravity of the rotation of the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage). And since the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage) has a portion where the height of the upper surface decreases as it moves away from the rotation center part, it is possible to reduce the portion where the carbon dioxide absorption solution does not spread by gravity and centrifugal force in the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage).

[0078] The carbon dioxide absorption solution supply part (inner shaft parts 512, 542) includes a hollow shaft-shaped member (inner shaft parts 512, 542) having an open lower end and disposed coaxially with the gas-liquid contact part (gas-liquid contact parts 53, 56 at each stage). The lower ends of the hollow shaft-shaped members (inner shaft portions 512 and 542) are disposed above the upper surfaces of the gas-liquid contact portions (the gas-liquid contact portions 53 and 56 of each stage), and the carbon dioxide absorption solution is configured to flow down from the lower ends of the hollow shaft-shaped members (inner shaft portions 512 and 542) to the upper surfaces of the gas-liquid contact portions (the gas-liquid contact portions 53 and 56 of each stage).

[0079] According to such a configuration, since the structure of the carbon dioxide absorption solution supply portion (inner shaft portions 512 and 542) can be simplified, it is possible to reduce the component cost of the carbon dioxide recovery apparatus 10 and improve the reliability.

[0080] The gas-liquid contact portion (the gas-liquid contact portions 53 and 56 of each stage) includes a container body (side plate portions 62 and bottom plate portion 63) having a bottomed cylindrical shape with an upper opening and a lower closure, and a lid portion 64 attached to the upper side of the container body (side plate portions 62 and bottom plate portion 63) so as to close the opening. a filler 60 configured to allow the carbon dioxide absorption solution to penetrate therein and filled inside the container 61; and the container body (side plate portions 62 and bottom plate portion 63) is configured to allow the gas (target gas) to flow into the container 61 from the outside to the inside and the carbon dioxide absorption solution to flow out from the inside to the outside, the lid portion 64 includes a ventilation portion 642 provided at the rotation center portion and allowing the gas (target gas) to pass therethrough in the vertical direction, and a non-ventilation portion 643 provided on the outer peripheral side of the ventilation portion 642 in a vertical view and not allowing the gas (target gas) to pass therethrough. The lower surface of the non-ventilation portion 643 is located below the lower end of the hollow shaft-shaped member (inner shaft portions 512 and 542) and includes a portion where the height decreases from the side closer to the rotation center portion to the side farther away.

[0081] According to such a configuration, the upper surface of the aggregate of the filler 60 accommodated inside the container 61 becomes lower as it goes from the side of the rotation center portion toward the outside. Therefore, it is possible to reduce the "portion where the carbon dioxide absorption solution does not spread" in the aggregate of the filler 60.

[0082] A through hole (inner shaft portion exposure hole 641) penetrating in the vertical direction is provided in the rotation center portion of the lid portion 64. The lower end of the hollow shaft-shaped member (inner shaft portions 512, 542) is exposed inside the container 61 through the through hole (inner shaft portion exposure hole 641).

[0083] According to such a configuration, the carbon dioxide absorption solution flowing down from the lower end of the hollow shaft-shaped member (inner shaft portions 512, 542) is directly supplied to the rotation center portion of the upper surface of the gas-liquid contact portion (gas-liquid contact portions 53, 56 at each stage). Then, the supplied carbon dioxide absorption solution diffuses and penetrates into the inside (aggregate of the filler 60) of the gas-liquid contact portion (gas-liquid contact portions 53, 56 at each stage) due to the centrifugal force and gravity of the rotation of the rotating body 36. Therefore, since a special mechanism for supplying the carbon dioxide absorption solution to the gas-liquid contact portion (gas-liquid contact portions 53, 56 at each stage) is not required, an increase in the cost of the recovery device 10 is not caused.

[0084] The bottom surface of the gas-liquid contact portion (gas-liquid contact portions 53, 56 at each stage) is such that the height of the region of the rotation center portion is higher than the height of the region on the outer peripheral side.

[0085] The region at the lower part and close to the rotation center portion of each stage of the gas-liquid contact portions 53, 56 contributes less to the improvement of the carbon dioxide absorption efficiency compared to other regions. Therefore, by making the region on the rotation center portion side of the bottom surface of the gas-liquid contact portion (gas-liquid contact portions 53, 56 at each stage) higher than the region on the outer peripheral side, it is possible to eliminate (or reduce such regions) the region that contributes less to the improvement of the carbon dioxide absorption efficiency. Therefore, the volume (mass) of the filler 60 can be reduced without causing a decrease in the carbon dioxide absorption efficiency.

[0086] The carbon dioxide absorption tower 11 includes a plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage), and the gas fed from the gas source (target gas source 90) passes through the plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage) in one direction, and the carbon dioxide absorption solution passes through the plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage) in a direction opposite to the one direction and contacts the gas (target gas) in each of the plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage) to absorb carbon dioxide contained in the gas (target gas). The plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage) are connected in series with each other in a multi-stage manner, The gas-liquid contact portions (gas-liquid contact portions 53, 56 at each stage) are rotatably arranged inside each of the plurality of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage). The carbon dioxide absorption solution supply portions (inner shaft portions 512, 542) are configured to be able to supply the carbon dioxide absorption solution to the upper surface of the rotation center of each of the gas-liquid contact portions (gas-liquid contact portions 53, 56 at each stage).

[0087] When the carbon dioxide absorption tower 11 includes a plurality of carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage) connected in series with each other and gas-liquid contact portions (gas-liquid contact portions 53, 56 at each stage) are arranged in each of the carbon dioxide absorption chambers (absorption chambers 32, 35 at each stage), compared with the configuration in which the carbon dioxide absorption tower 11 includes one carbon dioxide absorption chamber, an improvement in the carbon dioxide absorption efficiency (the ratio represented by the amount of absorbed carbon dioxide to the amount of carbon dioxide contained in the target gas) can be achieved.

[0088] As described above, the embodiments of the present invention have been described, but the technical scope of the present invention is not limited to the above embodiments. The present invention can be variously modified without departing from its gist, and these are also included in the technical scope of the present invention.

[0089] For example, in the above embodiment, an example in which the absorption tower 11 is a two-stage type is shown, but the number of stages (the number of absorption chambers) of the absorption tower 11 is not limited to two stages. For example, the absorption tower 11 may be a one-stage type, or may be a three-stage type or more.

Description of Symbols

[0090] 10… Carbon dioxide recovery device, 11… Carbon dioxide absorption tower, 32… Upper absorption chamber, 35… Lower absorption chamber, 36… Rotating body, 40… Driving force source, 51… Upper shaft portion, 52… Upper gas-liquid separation portion, 53… Upper gas-liquid contact portion, 54… Intermediate shaft portion, 60… Packing material (polymer of heavy components), 61… Container, 90… Target gas source, 511… Outer shaft portion of the upper shaft portion, 512… Inner shaft portion of the upper shaft portion, 541… Outer shaft portion of the intermediate shaft portion, 542… Inner shaft portion of the intermediate shaft portion

Claims

1. A carbon dioxide absorption tower configured to absorb carbon dioxide contained in the gas supplied from a gas source into a carbon dioxide absorption solution, which is disposed in a carbon dioxide absorption chamber provided inside the carbon dioxide absorption tower, and in which the carbon dioxide absorption solution can penetrate and the gas can pass through, and is configured to rotate about an axis substantially parallel to the vertical direction by the driving force of a driving force source. A gas-liquid contact part, A carbon dioxide absorption solution supply part configured to supply the carbon dioxide absorption solution to a rotation center part on the upper surface of the gas-liquid contact part, Comprising, A carbon dioxide recovery device, wherein the upper surface of the gas-liquid contact part has a portion whose height decreases as it moves away from the rotation center part.

2. The carbon dioxide recovery device according to claim 1, The carbon dioxide absorption solution supply part includes a hollow shaft-shaped member having an open lower end and arranged coaxially with the gas-liquid contact part, The lower end of the hollow shaft-shaped member is disposed above the upper surface of the gas-liquid contact part, and the carbon dioxide absorption solution is configured to flow down from the lower end of the hollow shaft-shaped member to the upper surface of the gas-liquid contact part. Carbon dioxide recovery device.

3. The carbon dioxide recovery device according to claim 2, The gas-liquid contact part is, A container having a bottomed cylindrical shape with an open upper side and a closed lower side, and a lid attached to the upper side of the container body so as to close the opening, A filler configured to allow the carbon dioxide absorption solution to penetrate therein and filled inside the container, Comprising, The container body is configured such that the gas can flow into the container from the outside of the container and the carbon dioxide absorption solution can flow out from the inside to the outside, The lid includes a ventilation part provided at the rotation center part and allowing the gas to pass through in the vertical direction, and a non-ventilation part provided on the outer peripheral side of the ventilation part in a vertical view and not allowing the gas to pass through, A carbon dioxide recovery device, wherein the lower surface of the non-ventilation part is located below the lower end of the hollow shaft-shaped member and includes a portion configured to have a decreasing height from the side closer to the rotation center part to the side farther away.

4. The carbon dioxide recovery device according to claim 3, A through hole penetrating in the vertical direction is provided at the rotation center part of the lid, The lower end of the hollow shaft-shaped member is exposed inside the container through the through hole. Carbon dioxide recovery device.

5. The carbon dioxide recovery device according to claim 1, A carbon dioxide recovery device, wherein the bottom surface of the gas-liquid contact part has a height in the region of the rotation center part higher than the height in the outer peripheral side region. **Claim 6** A carbon dioxide recovery device according to any one of Claims 1 to 5, wherein the carbon dioxide absorption tower includes a plurality of the carbon dioxide absorption chambers, the gas supplied from the gas source passes through the plurality of the carbon dioxide absorption chambers in one direction, and the carbon dioxide absorption solution passes through the plurality of the carbon dioxide absorption chambers in a direction opposite to the one direction while contacting the gas in each of the plurality of the carbon dioxide absorption chambers to absorb carbon dioxide contained in the gas, and the plurality of the carbon dioxide absorption chambers are connected in series with each other in a multi-stage manner; the gas-liquid contact part is rotatably disposed inside each of the plurality of the carbon dioxide absorption chambers; and the carbon dioxide absorption solution supply part is configured to be able to supply the carbon dioxide absorption solution to the upper surface of the rotation center of each of the gas-liquid contact parts.

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