RPB device and acid gas recovery system

Abstract

To improve recovery efficiency of an acid gas, such as carbon dioxide, from a gas.SOLUTION: A rotating packed bed (RPB) device includes: a casing in which a space is formed; a gas inflow port for supplying a gas; a gas discharge port for discharging the gas; a supply pipe which tubularly extends centered on an axis and supplies an absorbent; a liquid discharge port for discharging the absorbent; a loading part which is supported rotatably around the axis relative to the casing and has a contact space for placing the gas and the absorbent in contact with each other; and a gas discharge pipe which tubularly extends centered on the axis, covers the supply pipe from the radial outer side with respect to the axis, and communicates with the gas discharge port. The gas discharge pipe has: a plurality of gas inflow holes from which the gas flows in; and a discharge pipe body forming a gas discharge passage, which connects the gas inflow holes with the gas discharge port, between itself and an outer peripheral surface of the supply pipe.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to RPB devices and acid gas recovery systems. [Background technology]

[0002] In recent years, attention has been focused on the concentration of carbon dioxide (CO2) in the atmosphere from the perspective of carbon neutrality. From the perspective of reducing the concentration of carbon dioxide in the atmosphere, carbon dioxide capture systems that capture acidic gases such as carbon dioxide from flue gas are known. For example, in carbon dioxide capture systems using the chemical absorption method, an absorption liquid is circulated between a regenerator and an absorber to capture carbon dioxide from flue gas.

[0003] For example, Patent Document 1 describes a system in which an absorption tower is an RPB (Rotating Packed Bed) device. In the RPB device described in Patent Document 1, a packed section, which is made of packing, is rotated at high speed, and the supplied absorption liquid is turned into mist by centrifugal force and scattered in the radial direction. Then, the liquid mist scattered in the radial direction is brought into countercurrent contact with a gas containing carbon dioxide, thereby efficiently recovering carbon dioxide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 1,161,2854 Summary of the Invention [Problem to be solved by the invention]

[0005] In the RPB device described in Patent Document 1, only the absorbing liquid is supplied within a certain range in the vertical direction. As a result, the flow rate distribution of the mist-like absorbing liquid and the gas in the packed section becomes uneven in the vertical direction. Furthermore, when reacting gas with liquid, if the gas flow rate exceeds a certain value, the absorption rate of the gas relative to the liquid generally decreases. In an RPB device, if the gas flow rate becomes too high while the flow rate distribution of the absorbing liquid and the gas in the vertical direction is uneven, the recovery efficiency of acidic gases such as carbon dioxide from the RPB device also decreases. Therefore, it is desirable to improve the recovery efficiency of the target gas from the gas.

[0006] The present disclosure has been made to address the above-mentioned needs, and aims to provide an RPB device and a recovery system that can improve the recovery efficiency of target gas from gas. [Means for solving the problem]

[0007] In order to solve the above problems, the RPB device according to the present disclosure is an RPB device that brings gas containing acidic gas as a target gas for recovery into contact with an absorbing liquid, and includes a casing having an internal space formed about an axis, a gas inlet for supplying the gas into the interior of the casing, a gas outlet for discharging the gas from the interior of the casing, a supply pipe that extends in a tubular shape about the axis to the interior of the casing and supplies the absorbing liquid to the interior of the casing, a liquid outlet for discharging the absorbing liquid from the interior of the casing, and a liquid discharging device that is disposed inside the casing and that rotates about the axis relative to the casing. the casing is provided with a filling section that is movably supported and has a contact space therein that brings the gas and the absorption liquid into contact with each other, a rotary drive section that rotates the filling section, and a gas discharge pipe that extends in a tubular shape centered on the axis, covers the supply pipe from the outside in a radial direction based on the axis, and is in communication with the gas discharge port, the supply pipe having a plurality of liquid supply holes that supply the absorption liquid toward the filling section inside the casing, and the gas discharge pipe having a plurality of gas inlet holes through which the gas that has passed through the filling section flows in, and a discharge pipe body that forms a gas discharge flow path between the outer peripheral surface of the supply pipe and the plurality of gas inlet holes and the gas discharge port.

[0008] In addition, the acidic gas recovery system according to the present disclosure includes an absorber that contacts a gas containing an acidic gas as the target gas for recovery with an absorption liquid and discharges the absorption liquid that has absorbed the acidic gas and the gas from which the acidic gas has been removed, and a regenerator that strips the acidic gas from the absorption liquid discharged from the absorber and discharges the absorption liquid from which the acidic gas has been stripped and the gas containing the acidic gas, and the absorber has the above-mentioned RPB device. [Effects of the Invention]

[0009] According to the RPB device and acid gas recovery system of the present disclosure, it is possible to improve the recovery efficiency of the target gas from the gas. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic diagram showing a carbon dioxide capture system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram showing an RPB device according to a first embodiment. [Figure 3] 4 is an enlarged view of a main part illustrating the relationship between a supply pipe and a gas exhaust pipe according to the embodiment. FIG. [Figure 4] FIG. 2 is a schematic diagram illustrating the relationship between the RPB device and the external tank according to the present embodiment. [Figure 5] FIG. 10 is a schematic diagram showing an RPB device according to a second embodiment. [Figure 6] FIG. 10 is a schematic diagram showing an RPB device according to a third embodiment. [Figure 7] FIG. 10 is a schematic diagram showing an RPB device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, with reference to the accompanying drawings, embodiments for implementing the RPB devices 5, 5X, 5Y, 5Z, 5A, 5B, and 5C and the carbon dioxide capture system 1 according to the present disclosure will be described. However, the present disclosure is not limited to only these embodiments.

[0012] First Embodiment (Carbon dioxide capture system) The carbon dioxide capture system 1 is a facility for processing gas from a gas generation source (not shown). As shown in FIG. 1, the carbon dioxide capture system 1 of this embodiment is capable of separating and capturing carbon dioxide contained in gas using an absorption liquid, and supplying the captured carbon dioxide to another device. Examples of gas generation sources include waste incinerators, coal- or natural gas-fired power plants, gas turbines, gas engines, cement plants, steel plants, glass melting plants, and ethanol manufacturing plants. The gas from this gas generation source contains target gases to be captured, ash, heavy metals, and the like. Target gases to be captured include carbon dioxide (CO2), nitrogen oxides (NO), such as nitric oxide (NO), and the like. x ), sulfur dioxide (SO2) and other sulfur oxides (SO xAcidic gases include carbon dioxide (CO₂), hydrogen sulfide (HS), and other acidic gases (such as HCl, HCl, and HCl). (In this text, acidic gases including carbon dioxide are simply referred to as "carbon dioxide"). The gas source may be a facility external to the carbon dioxide capture system 1 that feeds atmospheric air into the carbon dioxide capture system 1. In other words, the carbon dioxide capture system 1 processes exhaust gases emitted from various facilities and atmospheric air as gases. The absorbent is preferably a highly viscous liquid to improve the gas absorption rate and reduce the regeneration energy required. For example, when absorbing carbon dioxide, an amine aqueous solution or a non-aqueous amine solution using a physical absorption solvent instead of water is preferred. Specific examples of amine absorbents that can be used include alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and diglycolamine (DGA). Hindered amines can also be used. Aqueous solutions of these compounds alone or a mixture of two or more of these compounds can also be used.

[0013] The carbon dioxide capture system 1 of this embodiment includes a supply cooler 11, an absorber 12, a regenerator 13, an exhaust gas cooler 14, an absorption liquid heat exchanger 15, a supply cooler gas supply line 16, a supply cooler exhaust gas line 17, a water circulation line 18, an absorber exhaust gas line 20, an absorber exhaust liquid line 19, an exhaust gas exhaust line 21, an exhaust gas cooling water circulation line 22, a steam supply line 23, a regenerator exhaust liquid line 24, and a regenerator gas exhaust line 25.

[0014] The supply cooler 11, the absorber 12, the regenerator 13, and the exhaust gas cooler 14 have RPB devices 5, 5X, 5Y, and 5Z, which will be described later. The supply cooler 11, the absorber 12, the regenerator 13, and the exhaust gas cooler 14 of this embodiment have RPB devices 5, 5X, 5Y, and 5Z, which have the same structure but are different in the types of gas and liquid supplied.

[0015] A portion of the gas containing carbon dioxide generated in the gas generation source is sent to the supply cooler 11 through the supply cooler gas supply line 16. The supply line is a pipe that connects the gas generation source and the supply cooler 11.

[0016] Gas containing carbon dioxide is introduced into the supply cooler 11 via a supply cooler gas supply line 16. Cooled water (e.g., drain water) is also introduced into the supply cooler 11 via a water circulation line 18. The supply cooler 11 cools the introduced gas by bringing the gas into contact with the water. The gas cooled by the supply cooler 11 is sent to a supply cooler exhaust gas line 17. In the supply cooler 11, gas at a temperature of 100 to 200°C is cooled to 40 to 50°C. The supply cooler 11 also sends the water heated by cooling the gas to the water circulation line 18.

[0017] The supply cooler exhaust gas line 17 sends the gas cooled in the supply cooler 11 to the absorber 12 via a blower 171. The supply cooler exhaust gas line 17 is a pipe that connects the supply cooler 11 and the absorber 12.

[0018] The blower 171 is disposed midway through the supply cooler exhaust gas line 17. The blower 171 increases the flow rate of the gas cooled by the supply cooler 11 and supplies the gas to the absorber 12. Specifically, the blower 171 is capable of increasing the pressure of the gas flowing through the supply cooler exhaust gas line 17. The blower 171 increases the pressure of the gas flowing through the supply cooler exhaust gas line 17, thereby increasing the flow rate of the gas introduced into the absorber 12. The blower 171 is capable of changing the gas pressure increase rate.

[0019] The water circulation line 18 circulates the water heated in the supply cooler 11 so that the water is cooled and sent back to the supply cooler 11. The water circulation line 18 has a water tank 181, a water pump 182, and a water cooler 183 along the way. The water tank 181 is an external tank that temporarily stores water discharged from the supply cooler 11. The water pump 182 pressurizes the water stored in the water tank 181 and sends it to the supply cooler 11 via the water cooler 183. The water cooler 183 cools the water by exchanging heat with the cooling liquid.

[0020] The gas cooled in the supply cooler 11 is introduced into the absorber 12 via a supply cooler discharge gas line 17. The absorbing liquid from which carbon dioxide has been stripped in the regenerator 13 is also introduced into the absorber 12 via a regenerator discharge liquid line 24. The absorber 12 brings the introduced gas into contact with the absorbing liquid to remove carbon dioxide from the gas. The absorber 12 separately discharges the absorbing liquid that has absorbed the carbon dioxide and the gas from which the carbon dioxide has been removed. The absorber 12 sends the gas from which the carbon dioxide has been removed to an absorber discharge gas line 20. The absorber 12 also sends the absorbing liquid from which carbon dioxide has been recovered to the regenerator 13 via an absorber discharge liquid line 19.

[0021] The absorber exhaust gas line 20 sends the gas from which carbon dioxide has been removed to the exhaust gas cooler 14. The absorber exhaust gas line 20 is a pipe that connects the absorber 12 and the exhaust gas cooler 14.

[0022] The absorber discharge liquid line 19 supplies the absorption liquid that has absorbed carbon dioxide from the absorber 12 to the regenerator 13. Here, the absorption liquid that is discharged from the absorber 12 and flows through the absorber discharge liquid line 19 is called a rich liquid. The rich liquid is an absorption liquid with a high concentration of carbon dioxide after carbon dioxide is absorbed in the absorber 12. The absorber discharge liquid line 19 has a rich tank 191 (tank) and a rich pump 192. The rich tank 191 is an external tank that temporarily stores the rich liquid discharged from the absorber 12. The rich pump 192 pressurizes the rich liquid stored in the rich tank 191 and sends it to the regenerator 13 via the absorption liquid heat exchanger 15.

[0023] The gas from which carbon dioxide has been removed in the absorber 12 is introduced into the exhaust gas cooler 14 via an absorber exhaust gas line 20. Cooled water is also introduced into the exhaust gas cooler 14 via an exhaust gas cooling water circulation line 22. The exhaust gas cooler 14 cools the introduced gas by bringing the gas into contact with water. The gas cooled in the exhaust gas cooler 14 is sent to an exhaust gas exhaust line 21. In the exhaust gas cooler 14, gas at a temperature of approximately 70 to 80°C is cooled to 40°C or less. The exhaust gas cooler 14 also sends the water heated by cooling the gas to the exhaust gas cooling water circulation line 22.

[0024] The exhaust gas exhaust line 21 is a pipe that discharges the gas discharged from the exhaust gas cooler 14 to the outside (outside the system). A tank equipped with a demister or the like for removing foreign matter may be disposed midway along the exhaust gas exhaust line 21.

[0025] The exhaust gas cooling water circulation line 22 cools the water heated in the exhaust gas cooler 14 and circulates it so that the water is sent to the exhaust gas cooler 14 again. The exhaust gas cooling water circulation line 22 has an exhaust gas cooling water tank 221, an exhaust gas cooling water pump 222, and an exhaust gas cooling water cooler 223 along the way. The exhaust gas cooling water tank 221 is an external tank that temporarily stores the water discharged from the exhaust gas cooler 14. The exhaust gas cooling water pump 222 pressurizes the water stored in the exhaust gas cooling water tank 221 and sends it to the exhaust gas cooler 14 via the exhaust gas cooling water cooler 223. The exhaust gas cooling water cooler 223 cools the water by heat exchange with a coolant and sends it to the exhaust gas cooler 14.

[0026] Steam heated in the reboiler 241 is introduced into the regenerator 13 via a steam supply line 23. The absorption liquid from which carbon dioxide has been recovered in the absorber 12 is also introduced into the regenerator 13 via an absorber discharge liquid line 19. The regenerator 13 heats the introduced steam by bringing it into contact with the absorption liquid, and strips carbon dioxide from the absorption liquid. The regenerator 13 separately discharges the absorption liquid from which carbon dioxide has been stripped and a gas mainly composed of carbon dioxide. The regenerator 13 sends the gas mainly composed of carbon dioxide to a regenerator gas exhaust line 25. The regenerator 13 also sends the absorption liquid from which carbon dioxide has been stripped to a regenerator discharge liquid line 24.

[0027] The regenerator gas exhaust line 25 is a pipe that discharges the gas primarily composed of carbon dioxide to another external (outside the system) facility. A tank equipped with a demister or the like to remove foreign matter or an additional cooler for cooling may be placed along the regenerator gas exhaust line 25. Depending on the intended use, the gas primarily composed of carbon dioxide discharged from the regenerator gas exhaust line 25 is compressed or liquefied, and then stored in a tank or transported via a pipeline to be stored inside an oil field or in an aquifer.

[0028] The regenerator discharge liquid line 24 supplies the absorption liquid from which carbon dioxide has been stripped, from the regenerator 13 to the absorber 12. Here, the absorption liquid discharged from the regenerator 13 and flowing through the regenerator discharge liquid line 24 is called lean liquid. The lean liquid is absorption liquid with a low concentration of carbon dioxide after carbon dioxide has been stripped in the regenerator 13. In other words, the lean liquid has a lower concentration of carbon dioxide than the rich liquid. The regenerator discharge liquid line 24 has a reboiler 241, a lean pump 242, and a lean cooler 243 along the way.

[0029] The reboiler 241 temporarily stores the lean liquid discharged from the regenerator 13. The reboiler 241 exchanges heat between steam supplied from the outside and the stored lean liquid, heating the lean liquid and converting the contained moisture into high-temperature steam. This steam is supplied to the regenerator 13 via the steam supply line 23. Here, the lean liquid is heated by steam in the reboiler, but an electric heater or the like may also be used. The lean pump 242 pressurizes the lean liquid stored in the reboiler 241 and sends it to the absorber 12 via the absorption liquid heat exchanger 15. The lean cooler 243 cools the lean liquid that has passed through the absorption liquid heat exchanger 15 by exchanging heat with a cooling liquid.

[0030] The absorbing liquid heat exchanger 15 exchanges heat between the rich liquid flowing through the absorber discharge liquid line 19 and the lean liquid flowing through the regenerator discharge liquid line 24. As a result, the absorbing liquid heat exchanger 15 heats the absorbing liquid flowing through the absorber discharge liquid line 19 in a state where the pressure has been increased by the rich pump 192 so as to travel from the absorber 12 to the regenerator 13. The absorbing liquid heat exchanger 15 also cools the absorbing liquid flowing through the regenerator discharge liquid line 24 in a state where the pressure has been increased by the lean pump 242 so as to travel from the regenerator 13 to the absorber 12.

[0031] (RPB device) The RPB devices 5, 5X, 5Y, and 5Z bring gas containing the target gas into contact with liquid. The RPB devices 5, 5X, 5Y, and 5Z are known as rotating packed beds. The RPB devices 5, 5X, 5Y, and 5Z apply centrifugal force approximately 100 times greater than normal gravity by rotating the packed section 54 disposed inside the casing 51 at high speed. As a result, the RPB devices 5, 5X, 5Y, and 5Z allow gas supplied from the radial outside and liquid supplied from the radial center and turned into mist by centrifugal force to flow parallel to the radial direction, resulting in countercurrent contact. Here, the radial direction refers to the radial direction of the RPB devices 5, 5X, 5Y, and 5Z, based on an axis O extending in the vertical direction Dv. In other words, the radial direction is the horizontal direction perpendicular to the vertical direction Dv. In the carbon dioxide capture system 1, at least the absorber 12 includes the RPB device 5. In this embodiment, the regenerator 13, the feed cooler 11, the absorber 12, and the exhaust gas cooler 14 include RPB devices 5X, 5Y, and 5Z.

[0032] In this embodiment, for the sake of explanation, the RPB device 5 of the absorber 12 will be described. The RPB device 5 of the absorber 12 is supplied with a gas containing carbon dioxide as the gas to be recovered and an absorption liquid as a liquid. The RPB devices 5X, 5Y, and 5Z of the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 are supplied with different gases and liquids. Specifically, the RPB device 5X of the regenerator 13 is supplied with steam discharged from the reboiler 241 and rich liquid discharged from the absorption liquid. The RPB device 5Y of the supply cooler 11 is supplied with gas from a gas generation source containing carbon dioxide and circulating water. The RPB device 5Z of the exhaust gas cooler 14 is supplied with the gas discharged from the absorber 12 and circulating water. The RPB devices 5, 5X, 5Y, and 5Z included in the absorber 12, regenerator 13, supply cooler 11, and exhaust gas cooler 14 have the same structure except for the gas and liquid that are supplied.

[0033] As shown in Figure 2, the RPB device 5 of this embodiment has a casing 51, a gas inlet 52, a gas outlet 53, a filling section 54, a rotary drive section 55, a sealing section 56, a supply pipe 57, a gas outlet pipe 58, a liquid outlet 59, and a cooling section 60.

[0034] The casing 51 is formed in a box shape centered on an axis O extending in the vertical direction Dv. A space is formed inside the casing 51. The casing 51 is fixed to an installation location by a support part 61 in an immovable state. The casing 51 of this embodiment has a casing main body 510 and a liquid receiving part 515.

[0035] The casing body 510 is formed in a cylindrical shape with a hollow interior centered on an axis O. The casing body 510 has a flat top plate 511 located at Dvu above the vertical direction Dv, a flat bottom plate 512 located at a distance Dvd below the top plate 511 in the vertical direction Dv, and cylindrical side plates 513 connecting the top plate 511 and the bottom plate 512 and extending in the vertical direction Dv. The top plate 511, the bottom plate 512, and the side plates 513 form a space inside the casing body 510 through which the gas and the absorbing liquid can flow.

[0036] The liquid receiving section 515 is disposed below the filling section 54 (described later) in the vertical direction Dv at a position Dvd. The liquid receiving section 515 is capable of storing the absorbing liquid. The liquid receiving portion 515 is connected to the liquid discharge port 59. The liquid receiving portion 515 forms a recess that is recessed downward Dvd in the vertical direction Dv from the bottom plate 512 of the casing body 510. In other words, the liquid receiving portion 515 is located at the lowest position Dvd in the vertical direction Dv in the casing 51. The liquid receiving portion 515 is formed away from the filling portion 54 in the vertical direction Dv.

[0037] The gas inlet 52 supplies gas into the inside of the casing 51 from the side surface of the casing 51. One or more gas inlet(s) 52 are arranged facing the side plate 513 of the casing main body 510. The gas inlet 52 is connected to the side plate 513 of the casing main body 510 in the vertical direction Dv. The gas inlet 52 is connected to the supply cooler exhaust gas line 17 outside the casing 51. The gas inlet 52 of this embodiment has a nozzle portion 521 and a connecting perforated plate 522.

[0038] Nozzle portion 521 is connected to the side surface of casing 51 so as to communicate with the interior of casing 51. Nozzle portion 521 is formed in a cylindrical shape that expands in diameter as it approaches side plate 513 of casing main body 510. Nozzle portion 521 is formed so that the flow path area is largest even at the connection position with side plate 513 of casing main body 510.

[0039] The connection porous plate 522 is arranged so as to block the connection position between the side surface of the casing 51 and the nozzle portion 521. The connection porous plate 522 has a plurality of holes or the like to add pressure loss so as to uniformly distribute the gas flow rate. Similar to the porous plate 541 described below, the connection porous plate 522 is a metal plate with a plurality of holes formed therein, such as a punch plate. The connection porous plate 522 is arranged at the connection position between the nozzle portion 521 and the side plate 513. In other words, the connection porous plate 522 is arranged so as to face the gas flow in the region of the nozzle portion 521 with the largest flow path area.

[0040] The gas outlet 53 is capable of discharging gas inside the casing 51. The gas outlet 53 discharges gas supplied from the gas inlet 52 into the inside of the casing main body 510 to the outside of the casing 51. The gas outlet 53 is disposed in the upper Dvu of the casing 51. The gas outlet 53 is connected to the top plate 511 of the casing main body 510. The gas outlet 53 is connected to the absorber exhaust gas line 20 outside the casing 51.

[0041] The packed section 54 has a contact space therein that brings the gas and the absorbing liquid into contact with each other. The packed section 54 is disposed inside the casing 51. The packed section 54 is supported rotatably about the axis O relative to the casing 51. The packed section 54 is cylindrical and disposed inside the casing main body 510. The packed section 54 is formed so that the thickness in the vertical direction Dv is smaller than the outer diameter in the radial direction. In other words, the cylindrical packed section 54 is formed so that the thickness dimension is smaller than the outer diameter. The packed section 54 is disposed inside the casing main body 510 so as to be rotatable without contacting the casing main body 510. The packed section 54 of this embodiment has a lower support plate 543, an upper support plate 544, a porous plate 541, and a space forming member 542.

[0042] The lower support plate 543 constitutes the bottom of the filling section 54. The lower support plate 543 is formed in a circular plate shape perpendicular to the axis O. The lower support plate 543 is disposed above Dvu in the vertical direction Dv with respect to the bottom plate 512 of the casing main body 510. The lower support plate 543 is rotatable without coming into contact with the casing main body 510. The lower support plate 543 supports the porous plate 541 and the space forming member 542 from below Dvd in the vertical direction Dv.

[0043] The upper support plate 544 constitutes the top of the filling section 54. The upper support plate 544 is formed in an annular shape perpendicular to the axis O. The upper support plate 544 is arranged at a distance Dvu above the lower support plate 543 in the vertical direction Dv. The upper support plate 544 is arranged at a distance Dvd below the top plate 511 of the casing main body 510 in the vertical direction Dv. The upper support plate 544 is rotatable without coming into contact with the casing main body 510. The upper support plate 544 supports the porous plate 541 and the space forming member 542 from above Dvu in the vertical direction Dv.

[0044] The perforated plates 541 are arranged at intervals in the radial direction. The perforated plates 541 have a plurality of holes. The perforated plate 541 is, for example, a metal plate with a plurality of holes formed therein, such as a punch plate. The perforated plate 541 is formed in a cylindrical shape centered on the axis O. A plurality of perforated plates 541 (three in this embodiment) are arranged at intervals in the radial direction. Specifically, the perforated plates 541 include a first perforated plate 541A, a second perforated plate 541B, and a third perforated plate 541C arranged in this order from the radially inner side (a position close to the axis O in the packed section 54). The perforated plates 541 are arranged to cover the space forming member 542 from the radially outer side (a position close to the side plate 513 in the packed section 54). The third perforated plate 541C, which is located at the outermost side in the radial direction, forms a side surface of the packed section 54. In other words, the third perforated plate 541C faces the gas inlet 52 in the radial direction. The multiple perforated plates 541 have the same structure. The multiple perforated plates 541 are fixed to the lower support plate 543 and the upper support plate 544, respectively. The perforated plates 541 are arranged so as to block the flow of gas between the lower support plate 543 and the upper support plate 544. Therefore, the perforated plates 541 are rotatable integrally with the lower support plate 543 and the upper support plate 544. The multiple holes are formed evenly spaced throughout the perforated plate 541. The gas and the absorbing liquid can move radially between the lower support plate 543 and the upper support plate 544 via the multiple holes.

[0045] The space forming member 542 forms a plurality of contact spaces therein. The space forming member 542 is arranged side by side with the perforated plate 541 in the radial direction. That is, the plurality of space forming members 542 are arranged alternately with the perforated plate 541 in the radial direction. The space forming member 542 is, for example, a metal or resin packing such as a wire mesh, a metal foam, or a structure packing. The space forming member 542 has a uniform thickness in the radial direction. The space forming member 542 is formed in a cylindrical shape centered on the axis O. A plurality of space forming members 542 (three in this embodiment) are arranged at intervals in the radial direction. Specifically, the space forming members 542 are arranged, in order from the inside in the radial direction, as a first space forming member 542A, a second space forming member 542B, and a third space forming member 542C. One perforated plate 541 is arranged adjacent to one space forming member 542 on the outside in the radial direction. That is, the first porous plate 541A is disposed radially outward from the first space forming member 542A. The second porous plate 541B is disposed radially outward from the second space forming member 542B. The third porous plate 541C is disposed radially outward from the third space forming member 542C. The multiple space forming members 542 have the same structure. The multiple space forming members 542 are fixed to the lower support plate 543 and the upper support plate 544, respectively.

[0046] The rotation drive unit 55 rotates the filling unit 54 around the axis O. The rotation drive unit 55 is connected to the filling unit 54. The rotation drive unit 55 of this embodiment has a drive unit main body 551 and a drive shaft 552.

[0047] The drive unit main body 551 is, for example, a motor. The drive unit main body 551 is arranged outside the casing 51. The drive unit main body 551 is arranged below the casing 51 at a position Dvd in the vertical direction Dv.

[0048] The drive shaft 552 rotates around the axis O. The drive unit body 551 is the output shaft of the motor. The drive shaft 552 passes through the liquid receiving section 515 from below Dvd in the vertical direction Dv and is connected to the lower support plate 543. The drive unit body 551 rotates the drive shaft 552 at a predetermined rotation speed, thereby rotating the filling section 54 at the same rotation speed as the drive shaft 552.

[0049] The seal portion 56 provides a seal between the stationary casing 51 and the rotating filling portion 54 and rotation drive portion 55. The seal portion 56 of this embodiment has a first seal portion 561 and a second seal portion 562.

[0050] The first seal portion 561 provides a seal between the casing 51 and the filling portion 54. The first seal portion 561 provides a seal between the top plate 511 and the upper support plate 544. The first seal portion 561 is formed in an annular shape with the axis O as its center.

[0051] The second seal portion 562 provides a seal between the casing 51 and the rotation drive portion 55. The second seal portion 562 provides a seal between the liquid receiving portion 515 and the drive shaft 552. The second seal portion 562 is formed in an annular shape centered on the axis O so as to cover the drive shaft 552 from the outside in the radial direction.

[0052] The supply pipe 57 is capable of supplying the absorbing liquid to the inside of the casing 51. The supply pipe 57 is capable of supplying the absorbing liquid radially outward. The supply pipe 57 supplies the absorbing liquid from the radially inner side of the packed section 54 toward the packed section 54. The supply pipe 57 extends in a tubular shape from the upper part Dvu of the casing 51 to the inside of the casing 51, with the axis O as its center. The supply pipe 57 is connected to the regenerator discharge liquid line 24 outside the casing 51.

[0053] The gas exhaust pipe 58 communicates with the gas exhaust port 53. The gas exhaust pipe 58 is capable of supplying gas inside the casing 51 to the gas exhaust port 53. The gas exhaust pipe 58 extends in a tubular shape from the upper portion Dvu of the casing 51 to the inside of the casing 51, with the axis O as its center. The gas exhaust pipe 58 covers the supply pipe 57 from the outside in the radial direction. In other words, the gas exhaust pipe 58 covers the supply pipe 57, thereby forming a double-pipe structure together with the supply pipe 57.

[0054] Here, we will explain the detailed structures of the supply pipe 57 and the gas exhaust pipe 58. As shown in Figures 2 and 3, the supply pipe 57 of this embodiment has a supply pipe main body 571, a plurality of protrusions 572, and a plurality of liquid supply holes 573.

[0055] Supply pipe main body 571 extends from the outside of casing main body 510 to the inside of casing main body 510. Supply pipe main body 571 is a cylindrical member fixed to top plate 511 while passing through top plate 511. The lower end of supply pipe main body 571 is disposed inside filling section 54. The lower end of supply pipe main body 571 is disposed at a distance Dv from lower support plate 543.

[0056] The protruding portion 572 protrudes radially outward from the outer circumferential surface of the gas discharge pipe 58 toward the filled portion 54. Specifically, the protruding portion 572 protrudes from the outer circumferential surface of the supply pipe main body 571. The protruding portion 572 protrudes radially toward the first space forming member 542A. The multiple protruding portions 572 are arranged at equal intervals on the outer circumferential surface of the supply pipe main body 571. The multiple protruding portions 572 are formed in a range equivalent to the height of the filled portion 54 in the vertical direction Dv. The multiple protruding portions 572 are formed over the entire circumferential range of the outer circumferential surface of the supply pipe main body 571 in the circumferential direction centered on the axis O. Each of the multiple protruding portions 572 is formed cylindrically. The multiple protruding portions 572 are fixed integrally to the outer circumferential surface of the supply pipe main body 571. The protruding portion 572 is formed, for example, by fixing a small-diameter short pipe with an orifice to the outer circumferential surface of the supply pipe main body 571 by welding.

[0057] The plurality of liquid supply holes 573 supply the absorbing liquid toward the packed section 54 inside the casing 51. The plurality of liquid supply holes 573 spray the absorbing liquid radially outward. The liquid supply holes 573 are openings on the outer side of the protruding section 572 in the radial direction. That is, the plurality of liquid supply holes 573 are formed in a range equivalent to the height of the packed section 54 in the vertical direction Dv. The plurality of liquid supply holes 573 are formed in a range over the entire circumference of the outer circumferential surface of the supply pipe main body 571 in the circumferential direction centered on the axis O. The liquid supply holes 573 are arranged at a position radially closer to the packed section 54 than a gas inlet hole 583 (described later). The liquid supply hole 573 is arranged radially outward from the outer circumferential surface of the gas exhaust pipe 58. That is, the liquid supply hole 573 is arranged radially closer to the first space forming member 542A than the gas inlet hole 583, and supplies the absorbing liquid toward the first space forming member 542A. Furthermore, among the multiple liquid supply holes 573, the hole diameter of the liquid supply holes 573 arranged above in the vertical direction Dv is smaller than the hole diameter of the liquid supply holes 573 arranged below in the vertical direction Dv. That is, in the supply pipe 57, the hole diameter of the liquid supply holes 573 varies depending on the position in the vertical direction Dv. The multiple liquid supply holes 573 are formed with different hole diameters so that the same flow rate of the absorption liquid can be supplied at any position in the vertical direction Dv, in relation to the pressure loss in the flow direction of the absorption liquid inside the supply pipe 57.

[0058] The gas exhaust pipe 58 of this embodiment has an exhaust pipe main body 581 and a plurality of gas inlet holes 583 .

[0059] The exhaust pipe main body 581 forms a gas exhaust flow path R between itself and the outer peripheral surface of the supply pipe 57. The gas exhaust flow path R is a gas flow path connecting the plurality of gas inlet holes 583 and the gas exhaust port 53. The exhaust pipe main body 581 extends from the top plate 511 to the inside of the casing main body 510. The exhaust pipe main body 581 is a cylindrical member fixed to the top plate 511. The lower end of the exhaust pipe main body 581 is disposed inside the filling section 54. The exhaust pipe main body 581 is disposed radially inward with respect to the first space forming member 542A. Similar to the supply pipe main body 571, the lower end of the exhaust pipe main body 581 is disposed at a distance in the vertical direction Dv from the lower support plate 543. In addition, a protrusion insertion hole 582 through which the protrusion 572 is inserted is formed in the outer peripheral surface of the exhaust pipe main body 581. Protrusion 572 is fixed in place in protrusion insertion hole 582 with protrusion 572 inserted therethrough. Specifically, protrusion 572 is welded to the outer circumferential surface of discharge pipe main body 581 in a state in which protrusion 572 is inserted through protrusion insertion hole 582 so as to protrude radially outward from the outer circumferential surface of discharge pipe main body 581. In this way, discharge pipe main body 581 fixes supply pipe 57.

[0060] Gas that has passed through the filling section 54 can flow into the gas inlet hole 583. A plurality of gas inlet holes 583 are formed on the outer peripheral surface of the supply pipe main body 571. Therefore, the plurality of gas inlet holes 583 guide the gas that has finally passed through the first space forming member 542A to the gas discharge flow path R inside the supply pipe main body 571. The plurality of gas inlet holes 583 are formed at positions shifted from the plurality of liquid supply holes 573. The plurality of gas inlet holes 583 are formed in a range equivalent to the height of the filling section 54 in the vertical direction Dv. The plurality of gas inlet holes 583 are formed in a range over the entire circumference of the outer peripheral surface of the discharge pipe main body 581 in the circumferential direction centered on the axis O.

[0061] 2, the liquid discharge port 59 discharges the absorption liquid inside the casing 51 to the outside. The liquid discharge port 59 is arranged on the lower Dvd of the casing 51. The liquid discharge port 59 is arranged on the lower Dvd in the vertical direction Dv with respect to the liquid receiving portion 515. The liquid discharge port 59 is connected to the absorber discharge liquid line 19 outside the casing 51.

[0062] 1 and 4, the liquid discharge port 59 is connected to a tank that stores the absorption liquid discharged from the liquid discharge port 59 by a U-shaped bend 7. Specifically, the liquid discharge port 59 of the RPB device 5 included in the absorber 12 is connected to the rich tank 191 by the U-shaped bend 7. The U-shaped bend 7 is a pipe that curves in the vertical direction Dv. In other words, the bend 7 curves so that it passes downward Dvd, upward Dvu, and downward Dvd in the vertical direction Dv in this order, and then connects to the rich tank 191.

[0063] 1, the liquid discharge port 59 of the RPB device 5Y included in the supply cooler 11 is connected to the water tank 181 by a U-shaped bend 7. Furthermore, the liquid discharge port 59 of the RPB device 5Z included in the exhaust gas cooler 14 is connected to the exhaust gas cooling water tank 221 by a U-shaped bend 7. Furthermore, in this embodiment, the liquid discharge port 59 of the RPB device 5X included in the regenerator 13 is not connected to the reboiler 241 by the U-shaped bend 7, but may be connected to the reboiler 241 by the U-shaped bend 7.

[0064] 2, the cooling unit 60 is capable of cooling the inside of the casing 51. The cooling unit 60 is arranged in contact with and wrapped around the side plate 513 of the casing main body 510. The cooling unit 60 is, for example, a heat exchanger through which cooling water flows.

[0065] (Gas flow in carbon dioxide capture system) In the carbon dioxide capture system 1 configured as described above, as shown in FIG. 1 , the gas flowing through the supply cooler gas supply line 16 is sent to the supply cooler 11. Cooled water is introduced into the supply cooler 11 via a water circulation line 18. Thereafter, in the supply cooler 11, the introduced gas and water are brought into countercurrent contact in the RPB device 5Y, thereby cooling the gas. The water heated by cooling the gas is sent from the supply cooler 11 via the water circulation line 18 to a water tank 181, a water pump 182, and a water cooler 183, in that order, and then sent to the supply cooler 11 again. The cooled gas is pressurized through a blower 171 via the supply cooler exhaust gas line 17 and sent to the absorber 12.

[0066] In the absorber 12, the gas whose pressure has been increased and whose flow rate has increased is brought into countercurrent contact with the absorbing liquid in the RPB device 5, thereby removing carbon dioxide. As a result, the gas from which carbon dioxide has been removed is sent to the exhaust gas cooler 14 via the absorber exhaust gas line 20.

[0067] Cooled water is introduced into the exhaust gas cooler 14 via the exhaust gas cooling water circulation line 22. Furthermore, in the exhaust gas cooler 14, the gas from which carbon dioxide has been removed is brought into countercurrent contact with water in the RPB device 5Z, thereby cooling the gas. The water heated by cooling the gas is sent from the exhaust gas cooler 14 via the exhaust gas cooling water circulation line 22 to an exhaust gas cooling water tank 221, an exhaust gas cooling water pump 222, and an exhaust gas cooling water cooler 223 in that order, and is then sent to the exhaust gas cooler 14 again. Furthermore, the cooled gas from which carbon dioxide has been removed is discharged to the outside (outside the system) via the exhaust gas exhaust line 21.

[0068] In the absorber 12, a rich liquid, which is an absorption liquid that has absorbed carbon dioxide, is produced. The rich liquid is sent in this order to a rich tank 191 and a rich pump 192 via an absorber discharge liquid line 19. The rich liquid is pressurized by the rich pump 192 and sent to the absorption liquid heat exchanger 15. The rich liquid is heated in the absorption liquid heat exchanger 15 and further flows through the absorber discharge liquid line 19 and sent to the regenerator 13. Steam heated in a reboiler 241 is introduced into the regenerator 13 via a steam supply line 23. Furthermore, in the regenerator 13, the pressurized rich liquid, whose flow rate has increased, comes into countercurrent contact with steam in the RPB device 5X, thereby stripping carbon dioxide from the rich liquid. As a result, a lean liquid, which is an absorption liquid from which carbon dioxide has been stripped, is produced in the regenerator 13. The lean liquid is sent to the reboiler 241 via the regenerator discharge liquid line 24. In the reboiler 241, the lean liquid is heated to generate steam from the lean liquid. Furthermore, the heated lean liquid is sent to the lean pump 242 via the regenerator discharge liquid line 24. The lean liquid is pressurized by the lean pump 242 and sent to the absorbing liquid heat exchanger 15. The lean liquid is cooled by heat exchange with the rich liquid in the absorbing liquid heat exchanger 15. The cooled lean liquid is further cooled in the lean cooler 243 and returned to the absorber 12. In this way, the absorbing liquid circulates between the absorber 12 and the regenerator 13. Furthermore, in the regenerator 13, an exhaust gas containing carbon dioxide is generated by stripping carbon dioxide from the rich liquid, and this exhaust gas is discharged to the outside (outside the system) through the regenerator gas exhaust line 25.

[0069] (Gas flow in RPB equipment) Next, the flow of gas and liquid in the RPB devices 5, 5X, 5Y, and 5Z will be described using the absorber 12 as an example. In the RPB device of the absorber 12, gas pressurized through the blower 171 is supplied to the gas inlet 52 via the supply cooler exhaust gas line 17. The gas supplied to the gas inlet 52 is guided by the nozzle section 521, passes through the connecting porous plate 522, and flows into the casing main body 510. Also, within the casing 51, the packed section 54 is rotated by the rotation drive section 55. The gas that flows into the casing main body 510 passes through the rotating packed section 54 and is supplied to the gas discharge pipe 58. Specifically, the gas that flows into the casing main body 510 passes through the packed section 54 in the following order: the third porous plate 541C, the third space forming member 542C, the second porous plate 541B, the second space forming member 542B, the first porous plate 541A, and the first space forming member 542A. The gas that has passed through the first space forming member 542A flows into the gas discharge flow path R from the plurality of gas inlet holes 583. The gas that has flowed into the gas discharge flow path R is sent from the gas discharge port 53 to the absorber discharge gas line 20.

[0070] The lean liquid, which is the absorbing liquid cooled in the absorbing liquid heat exchanger 15 and the lean cooler 243 and returned to the absorber 12 via the regenerator discharge liquid line 24, is supplied to the supply pipe 57. The lean liquid supplied to the supply pipe 57 passes through the inside of the supply pipe main body 571 and is sent to the plurality of protruding portions 572. The absorbing liquid is then supplied from the liquid supply holes 573 at the tips of the protruding portions 572 toward the rotating packed portion 54. Specifically, the absorbing liquid discharged from the plurality of liquid supply holes 573 is turned into mist by the centrifugal force of the rotating packed portion 54, and passes through the packed portion 54 in the order of the first space forming member 542A, the first porous plate 541A, the second space forming member 542B, the second porous plate 541B, the third space forming member 542C, and the third porous plate 541C. As the lean liquid mist passes through the first space forming member 542A, the second space forming member 542B, and the third space forming member 542C, it comes into countercurrent contact with the gas. As a result, a rich liquid is produced, which is an absorption liquid that has absorbed carbon dioxide from the gas. After passing through the third porous plate 541C, the lean liquid mist falls toward the bottom plate 512 inside the casing body 510. The lean liquid that falls on the bottom plate 512 accumulates in the liquid receiver 515 and is sent to the absorber discharge liquid line 19 through the liquid discharge port 59.

[0071] (Action and effect) In the RPB device 5 of this embodiment as described above, the gas discharge flow path R is formed between the discharge pipe main body 581 and the outer peripheral surface of the supply pipe main body 571, so that the supply pipe 57 and the gas discharge pipe 58 have a double-pipe structure. The absorbing liquid flows through a flow path inside the supply pipe main body 571 located at the radial center, and the gas flows through the gas discharge flow path R outside the supply pipe main body 571 and inside the discharge pipe main body 581. By allowing the gas and the absorbing liquid to flow separately through these two flow paths, it is possible to prevent the absorbing liquid from reacting with the gas inside the supply pipe 57 before the supply liquid is discharged toward the packing section 54. Therefore, unreacted absorbing liquid with high reaction efficiency can be stably supplied to the packing section 54. This improves the efficiency of recovering carbon dioxide, the target gas to be recovered from the gas.

[0072] The liquid supply hole 573 is formed as an outer opening of a cylindrical protruding portion 572 that protrudes radially outward beyond the outer circumferential surface of the gas discharge pipe 58. This makes it possible to easily form the liquid supply hole 573 at a position radially closer to the first space forming member 542A than the gas inlet hole 583. Furthermore, by arranging the liquid supply hole 573 at a position radially closer to the first space forming member 542A than the gas inlet hole 583, it is possible to prevent unreacted absorbing liquid that flows out from the liquid supply hole 573 from being caught in the gas flow and flowing into the gas discharge flow path R from the gas inlet hole 583. Therefore, it is possible to stably supply unreacted absorbing liquid to the filling section 54. This makes it possible to further improve the efficiency of recovering carbon dioxide, which is the target gas to be recovered from the gas.

[0073] The plurality of liquid supply holes 573 are formed so that the hole diameter of the liquid supply holes 573 arranged above in the vertical direction Dv is smaller than that of the liquid supply holes 573 arranged below in the vertical direction Dv. Therefore, the pressure loss in the flow direction of the absorption liquid inside the supply pipe 57 changes so as to increase as it approaches the lower end in the vertical direction Dv, but regardless of the change in pressure loss, the same flow rate of the absorption liquid can be supplied from the liquid supply holes 573 at any position in the vertical direction Dv. Therefore, the unreacted absorption liquid can be stably supplied to the packed section 54 with a uniform flow rate distribution in the vertical direction Dv. This can further improve the recovery efficiency of carbon dioxide, which is the target gas to be recovered from the gas.

[0074] In the packing section 54, a perforated plate 541 and a space-forming member 542 are arranged side by side in the radial direction. Therefore, the gas and absorption liquid flowing in the radial direction pass through the perforated plate 541, which has a plurality of holes formed therein, and the space-forming member 542, which has a contact space formed therein. By passing through the perforated plate 541, the flow rate distribution of the gas and absorption liquid flowing into the space-forming member 542 becomes uniform, thereby improving the reaction rate per unit volume of the space-forming member 542. Furthermore, by arranging the perforated plate 541 side by side with the space-forming member 542, even if centrifugal force acts on the space-forming member 542 due to the rotation of the packing section 54, the perforated plate 541 can support the space-forming member 542. This suppresses deformation, such as crushing, of the space-forming member 542, and suppresses a decrease in the reaction rate per unit volume of the space-forming member 542.

[0075] In this embodiment, the perforated plate 541 is disposed radially outward from the space forming member 542. That is, the perforated plate 541 can support the space forming member 542 from the radially outer side where centrifugal force is applied to the space forming member 542. Therefore, deformation of the space forming member 542 due to centrifugal force can be suppressed.

[0076] Furthermore, a plurality of perforated plates 541 and a plurality of space-forming members 542 are alternately fixed to the lower support plate 543 and the upper support plate 544. Therefore, the space between the lower support plate 543 and the upper support plate 544 can be firmly maintained by the perforated plates 541 and the space-forming members 542. In particular, the perforated plates 541 are metal plates, and the space-forming members 542 are metal packings. In this way, by alternately arranging the perforated plates 541 and the space-forming members 542 made of a metal material, deformation of the plurality of space-forming members 542 due to centrifugal force can be suppressed with higher precision. Therefore, it is possible to achieve both uniform gas flow distribution and the function of the perforated plates 541 and the space-forming members 542 as support bodies.

[0077] Gas inlet 52 has a nozzle portion 521 and a connecting porous plate 522. Therefore, at gas inlet 52, gas flows into casing main body 510 through nozzle portion 521, which increases in diameter as it approaches side plate 513 of casing main body 510. This makes it possible to reduce the inflow speed of gas when it flows into casing main body 510. Furthermore, because the gas passes through connecting porous plate 522, which is disposed at the connection position between nozzle portion 521 and side plate 513, it is possible to uniformly distribute the flow rate of gas flowing into casing main body 510. This makes it possible to suppress the influence of dynamic pressure of gas flowing into packed section 54 from the radial outside.

[0078] The inside of the casing body 510 is cooled by the cooling unit 60. Therefore, the gas and absorbing liquid that have flowed into the inside of the casing body 510 are cooled. In particular, the gas and absorbing liquid may come into contact and react, generating reaction heat. When reaction heat is generated in this way, the temperature inside the casing body 510 rises. On the other hand, the reaction rate of the gas and absorbing liquid increases as the temperature decreases. Therefore, cooling by the cooling unit 60 can suppress a decrease in the reaction rate of the gas and absorbing liquid. This can improve the reaction rate per unit volume of the gas and absorbing liquid that come into countercurrent contact within the space forming member 542.

[0079] The casing body 510 has a liquid receiving section 515 that forms a recess recessed from the bottom plate 512 toward Dvd in the vertical direction Dv. Therefore, the absorbing liquid that has passed through the filling section 54 falls and is stored in the liquid receiving section 515, and then discharged from the liquid discharge port 59. If the volume formed by the lower support plate 543 and the bottom plate 512 of the casing body is small, the absorbing liquid may accumulate in that section, causing the liquid height to be higher than that of the filling section 54, which may result in agitation loss in the filling section 54. By suppressing the loss that occurs when such accumulated absorbing liquid is agitated in the filling section 54, the agitation power can be reduced. This reduces the lining cost for rotating the filling section 54 in the rotation drive unit 55.

[0080] In the carbon dioxide capture system 1 of this embodiment, the absorber 12 has the RPB device 5 as described above, so that it is possible to improve the efficiency of capturing carbon dioxide, which is the target gas to be captured, from the gas.

[0081] The regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 each include other RPB units 5X, 5Y, and 5Z that bring other gases into contact with liquid. Specifically, the RPB unit 5X included in the regenerator 13 is supplied with steam discharged from the reboiler 241 and rich liquid discharged from the absorber 12. The RPB unit 5Y included in the supply cooler 11 is supplied with gas from a gas source containing carbon dioxide and circulating water. The RPB unit 5Z included in the exhaust gas cooler 14 is supplied with gas discharged from the absorber 12 and circulating water. Therefore, the entire carbon dioxide capture system 1 can improve the capture efficiency and cooling efficiency of not only carbon dioxide but also other target gases. This allows the carbon dioxide capture system 1 to be made more compact and the installation areas of the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 to be reduced.

[0082] The liquid discharge port 59 of the absorber 12 (RPB device 5) is connected to the rich tank 191 by a U-shaped bend 7. In the RPB device 5, liquids such as the absorption liquid cannot be continuously stored inside the casing 51. Therefore, by arranging a tank capable of storing liquid such as the rich tank 191 downstream of the RPB device 5, a buffer for liquid supply can be secured even if the rich pump 192 stops in an emergency such as a power outage. This allows for stable, continuous operation of the carbon dioxide capture system 1. In addition, because the U-shaped bend 7 is arranged upstream of the rich tank 191 and is liquid-sealed, short-passing of gas mixed with the absorption liquid discharged from the liquid discharge port 59 can be suppressed.

[0083] Second Embodiment Next, an RPB device 5A according to a second embodiment of the present disclosure will be described. In the second embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and their description will be omitted. The second embodiment differs from the first embodiment in that it includes an intermediate supply pipe 65 and in the configuration of the filling section 54A.

[0084] As shown in FIG. 5 , the RPB device 5A of the second embodiment further includes an intermediate supply pipe 65. The intermediate supply pipe 65 is capable of supplying the absorbing liquid to the inside of the packed section 54A. The intermediate supply pipe 65 has a plurality of holes that spray the absorbing liquid radially outward. The intermediate supply pipe 65 supplies the absorbing liquid to a range equivalent to the height of the packed section 54A in the vertical direction Dv. The intermediate supply pipe 65 is formed in a tubular shape. The intermediate supply pipe 65 is capable of supplying the absorbing liquid radially. The intermediate supply pipe 65 extends from an upper portion Dvu of the casing 51 to the inside of the packed section 54A. The intermediate supply pipe 65 is immovably fixed to the top plate 511. That is, the intermediate supply pipe 65 is stationary, similar to the casing 51. The intermediate supply pipe 65 extends parallel to the supply pipe 57. The intermediate supply pipe 65 supplies the absorbing liquid between two space forming members 542 that are aligned radially. Specifically, the filling section 54A of the RPB device 5A of the second embodiment does not have a second space forming member 542B. The intermediate supply pipe 65 supplies the absorbing liquid to the position where the second space forming member 542B was disposed. That is, the intermediate supply pipe 65 supplies the absorbing liquid between the first space forming member 542A and the third space forming member 542C in the radial direction. More specifically, the intermediate supply pipe 65 supplies the absorbing liquid between the first porous plate 541A and the second porous plate 541B in the radial direction. The lower end of the intermediate supply pipe 65 is disposed at a distance Dv from the lower support plate 543. The intermediate supply pipe 65 may have the same structure as the supply pipe 57.

[0085] (Action and effect) In this RPB device 5A, the absorbing liquid is supplied between the first space forming member 542A and the third space forming member 542C by the intermediate supply pipe 65. Therefore, the gas and absorbing liquid that have flowed into the packed section 54A are cooled by the absorbing liquid supplied from the intermediate supply pipe 65. By supplying and cooling the absorbing liquid from the intermediate supply pipe 65 in this manner, a decrease in the reaction rate of the gas and absorbing liquid can be suppressed. This makes it possible to improve the reaction rate per unit volume of the gas and absorbing liquid that are in countercurrent contact within the space forming member 542.

[0086] Furthermore, by supplying the absorbing liquid inside the filling section 54A through the intermediate supply pipe 65, the flow rate distribution of the absorbing liquid inside the filling section 54A becomes uniform. This also makes it possible to improve the reaction rate per unit volume of the space forming member 542.

[0087] The intermediate supply pipe 65 is not limited to a structure in which only one is provided in one RPB device 5A, as in this embodiment. A plurality of intermediate supply pipes 65 may be provided in one RPB device 5A. The intermediate supply pipe 65 may be a spray that is not inserted close to the lower support plate 543 inside the filling section 54 and is arranged to protrude vertically downward Dvd from the upper support plate 544, or may be a short intermediate supply pipe 65.

[0088] Third Embodiment Next, an RPB device 5B according to a third embodiment of the present disclosure will be described. In the third embodiment described below, components common to the first and second embodiments will be denoted by the same reference numerals in the drawings, and their description will be omitted. In the third embodiment, the configuration of a filling section 54B differs from that of the third embodiment.

[0089] As shown in FIG. 6, the filling section 54B of the third embodiment further includes a blocking plate 547. The blocking plate 547 covers the plurality of space forming members 542 from the radial outside. The blocking plate 547 is formed in a cylindrical shape without any holes. The blocking plate 547 connects the lower support plate 543B and the upper support plate 544. The blocking plate 547 separates the space between the lower support plate 543B and the upper support plate 544 from the space radially outside of the filling section 54B so that the gas flowing in from the gas inlet 52 does not flow toward the space forming member 542 from the radial outside. The blocking plate 547 is disposed in the same position as the third porous plate 541C in the first embodiment.

[0090] The lower support plate 543B also has a plurality of support through holes 549. The support through holes 549 penetrate the lower support plate 543B in the vertical direction Dv. The support through holes 549 are formed at positions overlapping with the space forming members 542 in the radial direction. In this embodiment, the support through holes 549 are respectively arranged below Dvd in the vertical direction Dv with respect to the first space forming member 542A, the second space forming member 542B, and the third space forming member 542C.

[0091] The rotation driver 55B of the third embodiment is capable of changing the rotation speed of the filling unit 54B in accordance with the flow rate of gas flowing into the gas inlet 52. Specifically, the driver main body 551B reduces the rotation speed of the drive shaft 552 when the flow rate of gas flowing into the gas inlet 52 decreases. Moreover, the driver main body 551B increases the rotation speed of the drive shaft 552 when the flow rate of gas flowing into the gas inlet 52 increases.

[0092] (Action and effect) In this RPB device 5B, the filling section 54B has a closure plate 547 and support through-holes 549. The closure plate 547 covers the radially outer side of the multiple space forming members 542, and the support through-holes 549 penetrate the lower support plate 543B at a position Dvd below the space forming members 542 in the vertical direction Dv. As a result, the gas flowing into the casing main body 510 from the gas inlet 52 flows into each space forming member 542 from a position Dvd below the vertical direction Dv, rather than from a radially outer side. Therefore, a crossflow is formed in the space forming member 542, in which the gas and the absorbing liquid flow perpendicularly to each other. Therefore, when the thickness in the vertical direction Dv is formed larger than the radial difference between the inner and outer radii, as in the filling section 54B of this embodiment, the gas and the absorbing liquid can be in contact with each other for a longer period of time within the space forming member 542.

[0093] Furthermore, the rotation speed of the filling unit 54B is changed by the rotation drive unit 55B in accordance with the flow rate of the gas flowing into the gas inlet 52. Therefore, an appropriate rotation speed can be maintained in accordance with the flow rate of the gas supplied to the filling unit 54B. This reduces lining costs when rotating the filling unit 54B with the rotation drive unit 55B. Note that the operation method of changing the rotation speed of the filling unit 54B in accordance with the gas flow rate or the flow rate of carbon dioxide contained in the gas is not limited to the third embodiment and may be applied to other embodiments.

[0094] <Fourth embodiment> Next, an RPB device 5C according to a fourth embodiment of the present disclosure will be described. In the fourth embodiment described below, components common to the first to third embodiments are denoted by the same reference numerals in the drawings, and their description will be omitted. In the fourth embodiment, the configuration of a filling section 54C differs from that of the first embodiment.

[0095] 7, the filling section 54C of the fourth embodiment has a flow path formed therein that meanders in the vertical direction Dv. Specifically, the filling section 54C of the fourth embodiment has a lower support plate 543B, an upper support plate 544, a third porous plate 541C (porous plate 541), a flow path forming plate 548, and a space forming member 545.

[0096] The flow path forming plates 548 are arranged at intervals in the radial direction. The flow path forming plates 548 are formed in a cylindrical shape without any holes. The flow path forming plates 548 cover the plurality of space forming members 545 from the radial outside. The flow path forming plates 548 are fixed only to the upper support plate 544. The flow path forming plates 548 extend downward Dvd from the upper support plate 544 in the vertical direction Dv. The flow path forming plates 548 are not connected to the lower support plate 543. In other words, the lower end of the flow path forming plate 548 in the vertical direction Dv is arranged with a gap above the lower support plate 543 in the vertical direction Dv. A plurality of flow path forming plates 548 (two in this embodiment) are arranged at intervals in the radial direction. Specifically, a first flow path forming plate 548A and a second flow path forming plate 548B are arranged in this order from the radial inside (a position close to the axis O in the filling section 54). The first flow path forming plate 548A and the second flow path forming plate 548B are arranged radially inward with a gap therebetween with respect to the third porous plate 541C. The first flow path forming plate 548A and the second flow path forming plate 548B are arranged radially inward with a gap therebetween.

[0097] The space forming member 545 of the fourth embodiment forms multiple contact spaces therein, similar to the space forming member 542 of the first embodiment. The space forming member 545 is, for example, a metal or resin packing such as a wire mesh, a metal foam, or a structure packing. The space forming member 545 is arranged radially alongside the flow path forming plate 548 and the third porous plate 541C. The space forming member 545 is fixed only to the lower support plate 543B. The space forming member 545 extends from the lower support plate 543 upward Dvu in the vertical direction Dv. The space forming member 545 is not connected to the upper support plate 544. In other words, the upper end of the space forming member 545 in the vertical direction Dv is arranged below the upper support plate 544 in the vertical direction Dv with a gap therebetween. Specifically, as the space forming member 545, a first space forming member 545A, a second space forming member 545B, and a third space forming member 545C are arranged in this order from the inside in the radial direction. A first flow path forming plate 548A is arranged radially outward from the first space forming member 545A. A second flow path forming plate 548B is arranged radially outward from the second space forming member 545B. A third porous plate 541C is arranged radially outward from the third space forming member 545C. The multiple space forming members 545 have the same structure.

[0098] (Action and effect) In such an RPB device 5C, a flow path that meanders vertically in the vertical direction Dv is formed inside the packed section 54C by the flow path forming plate 548 arranged at a distance in the vertical direction Dv from the lower support plate 543 and the space forming member 545 arranged at a distance in the vertical direction Dv from the upper support plate 544. Therefore, the passage time of the gas that has flowed into the packed section 54C from the third porous plate 541C can be made longer than when it passes linearly in the radial direction (horizontal direction), and as a result, the reaction rate per unit volume of the gas and the absorption liquid can be improved compared to when they are in face-to-face contact.

[0099] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0100] The RPB devices 5, 5A, 5B, and 5C are not limited to the structure of this embodiment. For example, the RPB devices 5, 5A, 5B, and 5C may not have a cooling unit 60. Furthermore, in the RPB devices 5, 5A, 5B, and 5C, the filling units 54, 54A, 54B, and 54C may be made of general packing (wire mesh, knit mesh, structure packing, metal foam, etc.) that does not have a perforated plate 541 and a space-forming member 542. Furthermore, in the RPB devices 5, 5A, 5B, and 5C, the gas inlet 52 may have a structure that does not have a nozzle unit 521 and a connecting perforated plate 522, such as a header structure that has a similar function of equalizing the gas flow rate. Furthermore, in the RPB devices 5, 5A, 5B, and 5C, the casing 51 may have a structure that does not have a liquid receiving unit 515. Furthermore, the RPB devices 5, 5A, 5B, and 5C may have a structure that combines the structure having the intermediate supply pipe 65 of the second embodiment with the structure having the closure plate 547 and multiple support through holes 549 of the third embodiment.

[0101] Furthermore, the gas to be recovered is not limited to carbon dioxide as in this embodiment. The gas to be recovered may be any acidic gas, such as hydrogen sulfide (H2S) or sulfur dioxide (SO2), or may be a combination of multiple acidic gases.

[0102] Furthermore, the filling sections 54, 54A, 54B, and 54C are not limited to the structures of the present embodiment. For example, the number of perforated plates 541 and space forming members 542 is not limited to three. Only one perforated plate 541 and one space forming member 542 may be disposed, or two or four or more perforated plates and space forming members 542 may be disposed.

[0103] Furthermore, when multiple perforated plates 541 are provided, the structures of the multiple perforated plates 541 are not limited to being the same. The multiple perforated plates 541 may have different numbers of holes and different arrangements depending on the positions where they are arranged. In this case, some of the multiple perforated plates 541 may have the same structure and other perforated plates 541 may have different structures, or all of the perforated plates 541 may have different structures.

[0104] Furthermore, when multiple space-forming members 542 are provided, the structures of the multiple space-forming members 542 are not limited to being identical. The multiple space-forming members 542 may have different types (wire mesh, knit mesh, metal foam, structure packing, etc.) and specifications (specific surface area, porosity), depending on their placement positions. In this case, some of the multiple space-forming members 542 may have the same structure while the other space-forming members 542 have different structures, or all of the space-forming members 542 may have different structures. The reaction rate of the gas and the absorbing liquid is high on the inner diameter side near the supply pipe 57 and low on the outer diameter side near the gas supply port. Accordingly, when changing the specifications of the space-forming members 542, a balance can be achieved between reducing the specific surface area of ​​the space-forming members 542 on the inner side in the radial direction and increasing the specific surface area of ​​the space-forming members 542 on the outer side. Similarly, when the space forming member 542 is made up of a plurality of layers of punch plates, the specifications (opening diameter, opening ratio, etc.) may be uniform or may vary, such as increasing the opening ratio in the radial direction.

[0105] Furthermore, the supply pipe 57 is not limited to the structure of this embodiment. For example, the supply pipe 57 does not need to have the protruding portion 572, as long as the outflow speed of the absorption liquid is sufficiently high. Therefore, the liquid supply hole 573 does not need to be formed in the protruding portion 572. This also simplifies the double-pipe structure of the supply pipe 57 and the gas discharge pipe 58. Furthermore, a heat insulating layer may be disposed on the inner or outer circumferential surface of the supply pipe 57 so that the absorption liquid is not heated by the gas flowing through the gas discharge flow path R. As the heat insulating layer, for example, a heat insulating coating formed by thermal spraying may be applied.

[0106] Furthermore, the plurality of liquid supply holes 573 are not limited to being formed so as to have different hole diameters in the vertical direction Dv as in this embodiment, and may be formed with the same hole diameter in the vertical direction Dv. In particular, when the pressure loss in the flow direction of the absorption liquid inside the supply pipe 57 is small, the plurality of liquid supply holes may be formed with the same hole diameter in the vertical direction Dv.

[0107] Furthermore, even when protruding portion 572 is formed, the structure is not limited to one in which protruding portion 572 is fixed by welding to supply pipe main body 571 or discharge pipe main body 581. Protruding portion 572 may have a structure in which the spray nozzle is fastened to a small-diameter short pipe with screws or the like, for example.

[0108] Furthermore, in the carbon dioxide capture system 1 of this embodiment, the absorber 12, the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 all have the RPB devices 5, 5X, 5Y, and 5Z, but the system is not limited to this structure. In the carbon dioxide capture system 1, it is sufficient that at least the absorber 12 has the RPB device 5. Therefore, in the carbon dioxide capture system 1, only some of the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 may have the RPB devices 5X, 5Y, and 5Z, and it is not necessary for all of the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 to have the RPB devices 5X, 5Y, and 5Z.

[0109] Furthermore, the absorber 12, regenerator 13, supply cooler 11, and exhaust gas cooler 14 are not limited to a structure having only one RPB unit 5, 5X, 5Y, 5Z. When the flow rate of the gas to be treated is high, multiple RPB units 5, 5X, 5Y, 5Z may be arranged in parallel. Furthermore, when a high gas recovery rate is required, multiple RPB units 5, 5X, 5Y, 5Z may be arranged in series. <Additional Notes> The RPB devices 5, 5A, 5B, and 5C and the acid gas recovery system described in each embodiment can be understood, for example, as follows.

[0110] (1) The RPB devices 5, 5A, 5B, and 5C according to the first aspect are RPB devices 5, 5A, 5B, and 5C that bring gas containing an acidic gas as a gas to be recovered into contact with an absorbing solution, and include a casing 51 having a space formed therein around an axis O, a gas inlet 52 that supplies the gas into the casing 51, a gas outlet 53 that discharges the gas from the casing 51, a supply pipe 57 that extends in a tubular shape around the axis O to the inside of the casing 51 and supplies the absorbing solution to the inside of the casing 51, a liquid outlet 59 that discharges the absorbing solution from the inside of the casing 51, and a contact tube that is disposed inside the casing 51 and is supported rotatably around the axis O relative to the casing 51 and brings the gas into contact with the absorbing solution. the supply pipe 57 has a plurality of liquid supply holes 573 that supply the absorption liquid toward the filling parts 54, 54A, 54B, 54C inside the casing 51, and the gas discharge pipe 58 has a plurality of gas inlet holes 583 through which the gas that has passed through the filling parts 54, 54A, 54B, 54C flows in, and a discharge pipe main body 581 that forms a gas discharge flow path R that connects the plurality of gas inlet holes 583 and the gas discharge port 53 between the outer circumferential surface of the supply pipe 57 and the supply pipe 57.

[0111] According to this configuration, the gas discharge flow path R is formed between the discharge pipe main body 581 and the outer peripheral surface of the supply pipe 57, so that the supply pipe 57 and the gas discharge pipe 58 have a double-pipe structure. The absorbing liquid flows through the flow path inside the supply pipe 57, and the gas flows through the gas discharge flow path R, which is outside the supply pipe 57 and inside the discharge pipe main body 581. By allowing the gas and the absorbing liquid to flow separately through these two flow paths, it is possible to prevent the absorbing liquid from reacting with the gas inside the supply pipe 57 before the supply liquid is discharged toward the packing sections 54, 54A, 54B, and 54C. Therefore, unreacted absorbing liquid with high reaction efficiency can be stably supplied to the packing sections 54, 54A, 54B, and 54C. This improves the efficiency of recovering the target gas from the gas.

[0112] (2) The RPB device 5, 5A, 5B, 5C according to the second aspect is the RPB device 5, 5A, 5B, 5C of (1), wherein the supply pipe 57 has a cylindrical protrusion 572 that protrudes radially outward beyond the outer surface of the gas discharge pipe 58 toward the filling sections 54, 54A, 54B, 54C, and the liquid supply hole 573 is an opening on the outer side of the protrusion 572 in the radial direction and is positioned closer to the filling sections 54, 54A, 54B, 54C in the radial direction than the gas inlet hole 583.

[0113] With this configuration, the liquid supply hole 573 can be easily formed at a position radially closer to the filling sections 54, 54A, 54B, and 54C than the gas inlet hole 583. Furthermore, by disposing the liquid supply hole 573 at a position radially closer to the filling sections 54, 54A, 54B, and 54C than the gas inlet hole 583, it is possible to prevent unreacted absorbing liquid flowing out from the liquid supply hole 573 from being caught in the gas flow and flowing into the gas discharge flow path R from the gas inlet hole 583. Therefore, the unreacted absorbing liquid can be stably supplied to the filling sections 54, 54A, 54B, and 54C. This further improves the efficiency of recovering the target gas from the gas.

[0114] (3) The RPB device 5, 5A, 5B, 5C according to the third aspect is the RPB device 5, 5A, 5B, 5C according to (1) or (2), wherein the hole diameter of the liquid supply holes 573 arranged above the vertical direction Dv is smaller than the hole diameter of the liquid supply holes arranged below the vertical direction Dv.

[0115] With this configuration, the pressure loss in the flow direction of the absorption liquid inside the supply pipe 57 changes so that it increases as it approaches the lower end in the vertical direction Dv, but regardless of the change in pressure loss, it is possible to supply absorption liquid at a similar flow rate from the liquid supply hole 573 at any position in the vertical direction Dv. Therefore, it is possible to stably supply unreacted absorption liquid to the packed section 54 in a nearly uniform state in the vertical direction Dv. This makes it possible to further improve the recovery efficiency of the target gas from the gas.

[0116] (4) The RPB device 5, 5A, 5B, 5C according to the fourth aspect is any one of the RPB devices 5, 5A, 5B, 5C according to (1) to (3), and the filling section 54, 54A, 54B, 54C has a porous plate 541 having a plurality of holes spaced apart in the radial direction, and a space forming member 542 arranged alongside the porous plate 541 in the radial direction and forming a plurality of the contact spaces therein.

[0117] With this configuration, the gas and absorption liquid flowing in the radial direction pass through the perforated plate 541 having a plurality of holes formed therein and the space-forming member 542 having a contact space formed therein. By passing through the perforated plate 541, the flow rate distribution of the gas and absorption liquid flowing into the space-forming member 542 becomes uniform, thereby improving the reaction rate per unit volume of the space-forming member 542. Furthermore, by arranging the perforated plate 541 next to the space-forming member 542, even if centrifugal force acts on the space-forming member due to the rotation of the filling sections 54, 54A, 54B, and 54C, the perforated plate 541 can support the space-forming member 542. This prevents the space-forming member 542 from collapsing and prevents a decrease in the reaction rate per unit volume of the space-forming member 542.

[0118] (5) The RPB device 5A according to the fifth aspect is the RPB device 5, 5A, 5B, 5C of (4), and further includes an intermediate supply pipe 65 that is tubular, extends from the upper Dvu of the casing 51 to the inside of the filling section 54A around the axis O, and supplies the absorption liquid to the inside of the filling section 54A, and the intermediate supply pipe 65 supplies the absorption liquid between the two space forming members 542 that are aligned in the radial direction.

[0119] According to this configuration, the gas and absorbing liquid that have flowed into the packed section 54A are cooled by the absorbing liquid supplied from the intermediate supply pipe 65. In this way, by supplying and cooling the absorbing liquid from the intermediate supply pipe 65, it is possible to suppress a decrease in the reaction rate of the gas and absorbing liquid. This makes it possible to improve the reaction rate per unit volume of the gas and absorbing liquid that are in countercurrent contact within the space forming member 542.

[0120] (6) The RPB device 5B according to the sixth aspect is the RPB device 5, 5A, 5B, 5C of (4), wherein the filling section 54B has a lower support plate 543B that supports the plurality of space forming members 542 from below Dvd in the vertical direction Dv, an upper support plate 544 that supports the plurality of space forming members 542 from above Dvu in the vertical direction Dv, and a flat blocking plate 547 that connects the lower support plate 543B and the upper support plate 544 and covers the plurality of space forming members 542 from the outside in the radial direction, and the lower support plate 543B has a support through hole 549 that penetrates in the vertical direction Dv at a position that overlaps with the space forming member 542 in the radial direction.

[0121] According to this configuration, the closure plate 547 covers the radially outer side of the space forming member 542, and the support through-holes 549 penetrate the lower support plate 543B at a position Dvd below the space forming member 542 in the vertical direction Dv. As a result, the gas that flows into the casing 51 from the gas inlet 52 flows into the space forming member 542 from a position Dvd below the space forming member 542 in the vertical direction Dv, rather than from a radially outer side. Therefore, a crossflow is formed in the space forming member 542, in which the gas and the absorption liquid flow perpendicularly to each other. Therefore, when the thickness in the vertical direction Dv is formed to be larger than the difference between the inner and outer radii in the radial direction, the gas and the absorption liquid can be in contact with each other for a longer period of time in the space forming member 542.

[0122] (7) The RPB device 5, 5A, 5B, 5C according to the seventh aspect is any one of the RPB devices 5, 5A, 5B, 5C according to (1) to (6), wherein the gas inlet 52 is connected to the side of the casing 51 so as to communicate with the interior of the casing 51, and has a cylindrical nozzle portion 521 whose diameter increases as it approaches the side, and a connecting porous plate 522 having a plurality of holes and arranged so as to block the connection position between the side and the nozzle portion 521.

[0123] According to this configuration, at gas inlet 52, gas flows into casing 51 through nozzle portion 521, which increases in diameter as it approaches the side surface of casing 51. This reduces the inflow speed of the gas as it flows into casing 51. Furthermore, because the gas passes through connecting perforated plate 522, which is disposed at the connection position between nozzle portion 521 and the side surface of casing 51, the flow rate distribution of the gas flowing into casing 51 can be made uniform. This reduces the effect of dynamic pressure of gas flowing into packed portions 54, 54A, 54B, and 54C from the outside in the radial direction.

[0124] (8) The RPB device 5, 5A, 5B, 5C according to the eighth aspect is any one of the RPB devices 5, 5A, 5B, 5C according to (1) to (7), and further includes a cooling unit 60 that cools the inside of the casing 51.

[0125] According to this configuration, the gas and absorbing liquid that have flowed into the inside of the casing 51 are cooled. Therefore, by cooling them using the cooling section 60, it is possible to suppress a decrease in the reaction rate of the gas and absorbing liquid. This makes it possible to improve the reaction rate per unit volume of the gas and absorbing liquid that come into countercurrent contact in the packed sections 54, 54A, 54B, and 54C.

[0126] (9) The RPB device 5, 5A, 5B, 5C according to the ninth aspect is any one of the RPB devices 5, 5A, 5B, 5C of (1) to (8), wherein the casing 51 is capable of storing the absorption liquid in a position Dvd below the filling section 54, 54A, 54B, 54C in the vertical direction Dv, and has a liquid receiving section 515 connected to the liquid discharge outlet 59.

[0127] With this configuration, the absorbing liquid that has passed through the filling sections 54, 54A, 54B, and 54C falls and accumulates in the liquid receiving section 515, and is then discharged from the liquid discharge port 59. This prevents the absorbing liquid that has accumulated at the bottom of the casing 51 from remaining inside the casing 51 and being agitated to the lower parts of the filling sections 54, 54A, 54B, and 54C due to the rotation of the filling sections 54, 54A, 54B, and 54C. This reduces losses that occur when the accumulated absorbing liquid is agitated in the filling sections 54, 54A, 54B, and 54C, and reduces the agitation power. This reduces the lining costs for rotating the filling sections 54, 54A, 54B, and 54C with the rotary drive sections 55 and 55B.

[0128] (10) The RPB device 5, 5A, 5B, 5C according to the tenth aspect is any one of the RPB devices 5, 5A, 5B, 5C of (1) to (9), wherein the rotation drive unit 55B changes the rotation speed of the filling unit 54, 54A, 54B, 54C according to the flow rate of the gas flowing into the gas inlet 52.

[0129] With this configuration, an appropriate rotation speed can be maintained in accordance with the flow rate of gas supplied to the filling units 54, 54A, 54B, and 54C. This makes it possible to reduce lining costs when rotating the filling units 54, 54A, 54B, and 54C with the rotary drive unit 55B.

[0130] (11) The RPB device 5, 5A, 5B, 5C according to the eleventh aspect is any one of the RPB devices 5, 5A, 5B, 5C according to (1) to (10), in which the filling section 54C forms a flow path that meanders vertically inside.

[0131] With this configuration, the gas that has flowed into the packed portion 54C flows through the packed portion 54C for a long period of time, which makes it possible to extend the reaction time between the gas and the absorbing liquid compared to when the gas passes in a straight line in the radial direction (horizontal direction).

[0132] (12) The acidic gas recovery system 1 according to the twelfth aspect includes an absorber 12 that brings an acidic gas as the gas to be recovered into contact with an absorption liquid and discharges the absorption liquid that has absorbed the acidic gas and the gas from which the acidic gas has been removed, and a regenerator 13 that strips the acidic gas from the absorption liquid discharged from the absorber 12 and discharges the absorption liquid from which the acidic gas has been stripped and the gas containing the acidic gas, and the absorber 12 has any one of RPB devices 5, 5A, 5B, 5C of (1) to (11).

[0133] With this configuration, the efficiency of recovering acid gases from the gas can be improved.

[0134] (13) The acidic gas recovery system according to the thirteenth aspect is the acidic gas recovery system of (12), further comprising a supply cooler 11 that cools the gas and supplies it to the absorber 12, and an exhaust gas cooler 14 that cools the gas from which the acidic gas has been removed and that is supplied from the absorber 12, and the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14 have other RPB devices 5X, 5Y, 5Z that bring other gases into contact with liquids.

[0135] This configuration improves the recovery efficiency of not only the acid gas but also other target gases throughout the entire acid gas recovery system, thereby making it possible to make the acid gas recovery system 1 more compact and reducing the installation area of ​​the regenerator 13, the supply cooler 11, and the exhaust gas cooler 14.

[0136] (14) The acidic gas recovery system according to the fourteenth aspect is the acidic gas recovery system 1 of (12) or (13), and includes a tank for storing the absorption liquid discharged from the liquid discharge outlet 59, and a U-shaped bend 7 that connects the tank to the liquid discharge outlet 59 and curves in the vertical direction Dv.

[0137] This configuration provides a liquid storage tank downstream of the RPB devices 5, 5A, 5B, and 5C, ensuring a buffer for liquid supply even if the pumps or other equipment stop during an emergency, such as a power outage. This allows for stable, continuous operation of the acid gas recovery system. Furthermore, the provision of a U-shaped bend 7 that is convex above the vertical direction Dv (Dvu) enables liquid sealing, preventing short-path gas flow in the absorbing liquid supplied from the liquid outlet 59. [Explanation of symbols]

[0138] 1...Carbon dioxide capture system (acid gas capture system) 11…Supply cooler 12...Absorber 13...Regenerator 14...Exhaust gas cooler 15...Absorption liquid heat exchanger 16...Supply cooler gas supply line 17...Supply cooler exhaust gas line 171...Blower 18...Water circulation line 181...Water tank 182...Water pump 183…Water cooler 19...Absorber discharge liquid line 191...Rich Tank 192…Rich Pump 20...Absorber exhaust gas line 21...Exhaust gas exhaust line 22...Exhaust gas cooling water circulation line 221...Exhaust gas cooling water tank 222...Exhaust gas cooling water pump 223...Exhaust gas cooling water cooler 23...Steam supply line 24...Regenerator discharge liquid line 241...Reboiler 242...Lean pump 243...Lean Cooler 25...Regenerator gas exhaust line 5,5A,5B,5C,5X,5Y,5Z...RPB device 51...Casing 510...Casing body 511...Tabletop 512…Bottom plate 513...Side panel 515...Liquid receiving part 52...Gas inlet 521...Nozzle part 522...Connection perforated plate 53...Gas outlet 54,54A,54B,54C…Filling section 541...Perforated plate 541A…First perforated plate 541B…Second perforated plate 541C…Third perforated plate 542, 545...Space forming members 542A, 545A...First space forming member 542B, 545B... Second space forming member 542C, 545C...Third space forming member 543,543B…Lower support plate 544...Upper support plate 548...flow path forming plate 548A...First flow path forming plate 548B…Second flow path forming plate 55, 55B...Rotation drive unit 551, 551B...Drive unit body 552...Drive shaft 56...Seal part 561...First seal part 562...Second seal part 57…Supply pipe 571…Supply pipe body 572...Protrusion 573…Liquid supply hole 58...Gas exhaust pipe 581…Discharge pipe body 582...Protrusion insertion hole 583...Gas inlet R...Gas exhaust flow path 59…Liquid outlet 60...Cooling section 61...Support Department O…Axis line 7...Bend 65…Intermediate supply pipe 547…occlusion plate 549...Support through hole Dv: vertical direction Dvu…upper DVD…Downward

Claims

1. An RPB apparatus that brings a gas containing an acidic gas as a gas to be recovered into contact with an absorption liquid, a casing having an internal space centered on an axis; a gas inlet for supplying the gas into the interior of the casing; a gas exhaust port for exhausting the gas inside the casing; a supply pipe extending in a tubular shape about the axis to the inside of the casing and supplying the absorption liquid to the inside of the casing; a liquid outlet for discharging the absorption liquid inside the casing; a packed section disposed inside the casing, supported rotatably about the axis relative to the casing, and having a contact space therein for bringing the gas into contact with the absorption liquid; a rotation drive unit that rotates the filling unit; a gas discharge pipe extending in a tubular shape centered on the axis, covering the supply pipe from the outside in a radial direction based on the axis, and communicating with the gas discharge port; the supply pipe has a plurality of liquid supply holes that supply the absorption liquid toward the packed section inside the casing, The gas exhaust pipe is an RPB apparatus having a plurality of gas inlet holes through which the gas that has passed through the filling section flows in, and an exhaust pipe main body that forms a gas exhaust flow path connecting the plurality of gas inlet holes and the gas exhaust port between the outer surface of the supply pipe.

2. the supply pipe has a cylindrical protruding portion that protrudes radially outward beyond an outer circumferential surface of the gas discharge pipe so as to face the filling portion, The RPB apparatus according to claim 1 , wherein the liquid supply hole is an opening on the outer side of the protrusion in the radial direction and is disposed at a position closer to the filling portion in the radial direction than the gas inlet hole.

3. The RPB device according to claim 1 or 2, wherein the hole diameter of the liquid supply holes arranged vertically upward is smaller than the hole diameter of the liquid supply holes arranged vertically downward.

4. The filling section is a perforated plate having a plurality of holes spaced apart in the radial direction; The RPB apparatus according to claim 1 or 2, further comprising a space forming member arranged alongside the perforated plate in the radial direction and forming a plurality of the contact spaces therein.

5. an intermediate supply pipe formed in a tubular shape, extending from above the casing to the inside of the packed section with the axis as its center, and supplying the absorption liquid to the inside of the packed section; The RPB apparatus according to claim 4 , wherein the intermediate supply pipe supplies the absorbing liquid between the two space forming members arranged in the radial direction.

6. The filling section is a lower support plate that supports the plurality of space forming members from below in the vertical direction; an upper support plate that supports the plurality of space forming members from above in the vertical direction; a flat closing plate that connects the lower support plate and the upper support plate and covers the plurality of space forming members from the outside in the radial direction, The RPB apparatus according to claim 4 , wherein the lower support plate has a support through-hole that penetrates in the vertical direction at a position that overlaps with the space forming member in the radial direction.

7. The gas inlet is a cylindrical nozzle portion connected to a side surface of the casing so as to communicate with the interior of the casing, the nozzle portion expanding in diameter as it approaches the side surface; The RPB apparatus according to claim 1 or 2, further comprising: a connecting perforated plate having a plurality of holes, the connecting perforated plate being arranged so as to block a connection position between the side surface and the nozzle portion.

8. The RPB apparatus according to claim 1 or 2, further comprising a cooling unit that cools the inside of the casing.

9. 3. The RPB apparatus according to claim 1, wherein the casing has a liquid receiving portion that is capable of storing the absorption liquid below the filling portion in the vertical direction and is connected to the liquid discharge port.

10. The RPB apparatus according to claim 1 or 2, wherein the rotation drive unit changes the rotation speed of the packed unit in accordance with the flow rate of the gas flowing into the gas inlet.

11. 3. The RPB apparatus according to claim 1, wherein the filling section has a meandering flow path formed therein in a vertical direction.

12. an absorber that brings a gas containing an acidic gas as a target gas for recovery into contact with an absorption liquid and discharges the absorption liquid that has absorbed the acidic gas and the gas from which the acidic gas has been removed; a regenerator that strips the acidic gas from the absorption liquid discharged from the absorber and discharges the absorption liquid from which the acidic gas has been stripped and the gas containing the acidic gas, The acid gas recovery system according to claim 1 or 2, wherein the absorber comprises the RPB device.

13. a supply cooler that cools the gas and supplies it to the absorber; The gas from which the acid gas has been removed is cooled by an exhaust gas cooler.

13. The acid gas recovery system of claim 12, wherein the regenerator, the feed cooler, and the exhaust gas cooler comprise other RPB units that contact other gases and liquids.

14. a tank that stores the absorption liquid discharged from the liquid discharge port; 13. The acid gas recovery system according to claim 12, further comprising a U-shaped bend that connects the tank and the liquid discharge outlet and curves convexly upward in the vertical direction.

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